Category: techniques

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acute mesenteric ischemia chronic mesenteric ischemia complications CTA hybrid technique imaging techniques Technology visceral malperfusion

Abdominal Stroke Alert!

It is a rare day that passes without the announcement of a stroke alert at CCAD. A reflex arc of activity is initiated, as time becomes the critical metric of success. Patients with strokes have a limited window of time to reverse the effects of the arterial occlusion, and the whole hospital is organized around getting the patient into the angiographic suite to open up blood vessels. If you watch it happen, it is the pinnacle of modern medicine, to achieve what only a decade ago was deemed unachievable. It was built around a foundation laid by cardiologists for heart attacks -the STEMI alert. The teams practice like racing pit crews with a stopwatch to get a patient from the emergency room, to CT scan, to angio suite. A long time ago, as a young surgeon, I had to work hard to get institutional support of ruptured AAA and cold legs. Vascular surgery has traditionally struggled to get recognition for its patients, their diseases, and its work, which is nothing less than the most important safety net for any large general multi-specialty hospital, critical infrastructure like oxygen plumbing and backup generators. As I transition to that weird designation of mid-career surgeon (please don’t call me a senior surgeon), I have also appreciated that Steve Jobs aphorism about good artists copying, great artists stealing. It’s only stealing if you don’t give credit. Here is what I borrowed from the neurologists.

Acute mesenteric ischemia is an abdominal stroke. Use it in your conversations with other people as you speed your patients way into the angio suite. The reflex arc is in there. For the emergency department, the operating room, and all the physicians, acute mesenteric ischemia sounds like tummy trouble, but abdominal stroke brings sudden clarity to conversations like:

“Well, you’re in line behind a gallbladder and a cystoscopy. Is the patient NPO?”

Me: “It’s an abdominal stroke. We literally only have a few hours before the patient dies…”

“I’ll bring the backup team in!”

The patient is a middle aged man with risk factors of NIDDM and prior history of DVT who developed severe mid-abdominal pain at 5pm. He came to the ED at around 11pm and had a general surgery consultation who ordered a CT Angiogram showing SMA occlusion (pictured below).

Acute Mesenteric Ischemia case presentation

Acute Mesenteric Ischemia case presentation (1)
Heparin was started, and at 11:30, vascular surgery was consulted. The patient had a soft, doughy texture to his abdomen, but great pain with palpation -classic pain out of proportion to the exam. Determining the patient to have acute mesenteric ischemia from a thromboembolism, I took the patient to our hybrid angiographic OR suite with the plan for arteriography, possible open thrombectomy, and exploratory laparotomy.
Arteriography from femoral access showed an occlusion of the SMA beyond the middle colic artery, a typical pattern for an embolism that occurs when embolism lodges distally and propogates proximally (image below).

Acute Mesenteric Ischemia case presentation (2)
I got Glidewire access into the ileocolic terminus of the SMA, exchanged for a Rosen wire, over which I placed an 8F sheath into the proximal SMA. This was a rather large sheath meant to catch thrombus as I suctioned it out with a 6F Penumbra catheter. This is another technique I borrowed from the neurointerventionalists. Whenever a stroke alert is going on, curiosity drives me to peak in and see what marvelous gadget or gewgaw they are using, and I was impressed by how efficiently the neurointerventionalists were able to get to the smallest thrombus in the furthest branch vessels. I was prepped for open thrombectomy, consented for bypass if necessary, but having experience in suctioning clot through single catheters and sheaths, I thought the simple design of the Penumbra and its efficacy in the cerebral system could easily translate into the mesenteric.The problem with open thrombectomy is the inability to see if you have cleared thrombus from all the branches unless you do an arteriogram after you’ve completed your procedure. This may be a significant contributor to the 20-30% bowel resection rate that occurs on second look laparotomy in my old paper and in the literature since its publication.

The Penumbra was effective in removing much of the fresh thrombus, but I was also cognizant of the fact that pulling out the catheter will draw clot into the 8F sheath that did not make it into the catheter. I placed a wire, and removed the sheath to expel much of the bulky thrombus (picture below).

Acute Mesenteric Ischemia case presentation (3)

The completion angiogram (below) doesn’t show the intermediate angiograms showing thrombus that embolized to other arteries as I manipulated the catheters and thrombectomized -I was able to successfully retrieve these with selective catheterization, another neurointerventional series of maneuvers that I have successfully borrowed.

Acute Mesenteric Ischemia case presentation (4)
After being satisfied with the completion, I removed the sheaths and explored the abdomen finding this segment of infarcted small bowel (next image).

Acute Mesenteric Ischemia case presentation (6)
There was no question in my mind that there would be some dead bowel based on the time course described by the patient. Despite my excitement about calling for GIA staplers -I am general surgery boarded- I called in the general surgeons for their help in resecting and anastomosing this segment of bowel. They would be the ones taking the patient back for any second look laparotomy, although in this patient, I determined that there would likely be no need. After the anastomosis was completed, I did a Wood’s Lamp examination (pictured), which is accomplished with a black light after giving the patient an ampule or two of Fluorescein.

Acute Mesenteric Ischemia case presentation (7)
The bowel had a splotchy fluorescence pattern which is typical of ischemia-reperfusion. This is where you have to ask the anesthesiologist and any critical care specialist who follows -no pressors please! Edema won’t kill an anastomosis as badly as ischemia will, and the gut is as sensitive to norepinephrine as are the toes. Workup in the hospital including echocardiography and CTA of the entire aorta failed to reveal a proximal source or cardiac shunts or thrombus. The patient recovered and has recently followed up, eating well, and tolerating his anticoagulation which he will be on for life.
I sent out the pictures to my neurointerventional friends with some glee, but also with the purpose of informing them that in the case that the vascular surgeons become incapacitated or quarantined due to the COVID-19 pandemic, their skills would be recruited in the care of an abdominal stroke -a blood vessel is a blood vessel.
Acute mesenteric ischemia should be the first thing on everyone’s differential of sudden onset abdominal pain because of its time dependence, yet it does not have the same resonance to the unfamiliar as abdominal stroke. Survival is dismal when too much time and intestinal death has occurred. When associated with the stroke alert concept, it translates into processes already in place throughout the hospital and it becomes natural for everyone to appreciate the urgency of treating abdominal stroke. This is the system adopted by Roussel et al. in France, where they have regionalized care of intestinal stroke. They report mortality rate of 6.9%, which is in a selected population, but significantly lower than the traditionally reported 30-60% mortality.

I am still an advocate of an open approach, especially when angiographic resources are unavailable, and every trainee needs to be able to describe the exposure of the SMA, and management of acute mesenteric ischemia. Hopefully, everyone will appreciate the urgency of all the various ischemic conditions manifest in the peripheral circulation, but rebranding them as a stroke (leg stroke, hand stroke, intestinal stroke…) is helpful. Finally, there is no survival with dead bowel -it must be found through exploration and resected.

Reference:

Roussel A, Castel Y, et al. Revascularization of acute mesenteric ischemia after creation of a dedicated multidisciplinary center. 2015 Nov;62(5):1251-6. doi: 10.1016/j.jvs.2015.06.204.

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acute limb ischemia humor limb salvage techniques training

Of Clot, Tofu, and Cheese

The process of clotting is something vascular surgeons take for granted, but patients may have a hard time understanding what a clot is because in most people’s experience, it is rare for someone to see enough blood to form clot. How many patients or even health care providers have seen a tube or a basin of blood clot? So how do we describe clot to patients? I think the solution lies in food.

Most people who know me will say that I propose food as the answer for most things but hear me out. In describing clot, food is particularly salient. Clot is protein made insoluble, and there are many foods that have similar properties. Tofu, jello, and cheese and their making can give context where the word “clot” cannot.

All are made by taking a solution of protein and allowing them to form clumps that cause them to fall out of solution. It may require an acid, as in the case of tofu and cheese, but mere time and cooling may be sufficient as in the case of jello. And like these, clot may take on a soft crumbly quality when it is fresh clot, to a tenacious formed clump when given enough time. The difference is like silken or soft tofu and firm tofu. Or fresh ricotta cheese before it has time to set in its mold and the firmer cheese you get after weeks of curing.
With enough time, you get a hard substance that you can slice with a knife, like a dry cheddar or Parmesan. That is how I think of clot. It can be soft and formless like early jello before it is ready to eat. Or it can be hard and formed like mature dry cheese. The softer it is, the easier it is to dissolve or suck out via gadget or catheter, but there is a time factor to this softness -thing of your jello setting and hardening in your fridge. The harder the thrombus is, the less likely it is you can remove it with catheters and more likely you will have success with an operation as in the first picture. The harder stuff in fact crumbles well like a parmesan cheese and is harder to remove.

Burrata, handmade in Calabria is similar to the kind of semi-mature clot that deforms well but is tenacious and difficult to break up and remove except in one piece.

There are several things to draw from this with regard to devices designed to retrieve clot. Clot can occlude catheters as much as they can occlude arteries. Clot retrieval depends on net output of fresh clot that deforms well and flows well but fails in the hardened brittle clot that is well organized and adherent. Retrieving these crusty dried clot matter may be impossible for a device that depends on clot deformability or a maximum particle size, and these clots are the ones that are more partial to crumbling and embolizing. All devices must accept the fact that the unclogging is done in a flowing circulatory system where items swept downstream have the consequence of killing tissues whose arteries are blocked by emboli. There is always embolism with minimally invasive approaches. These devices make sense for hard to access circuits like the brain, but make far less sense in circuits like the extremities where surgical control is relatively low risk and results in reversal of blood flow -like in TCAR. Each of these devices can cost several thousand dollars. The fact is, operations can be faster and safer because embolism can be controlled and a wider range of clots, and larger amounts of it, can be removed at a lower cost. The first picture shows the results of a popliteal cut down and tibial thrombectomy where inflow was first restored in the below knee popliteal artery, and clot retrieved from each of the three tibial vessels (misleadingly, the tibial thrombus is all lined up), and a simultaneous 4 compartment fasciotomy performed, all under 90 minutes with no use of contrast. Unfortunately, open thrombectomy is a bit of a lost art in that many of the maneuvers and steps required to revascularize a limb successfully with no preoperative imaging requires experience. A younger patient with an arrthymia related embolism and normal soft arteries is approached far differently from an older person with atherosclerosis and diabetes, where open thrombectomy is better suited for the first, and catheter based approaches better for the latter.

Diagnostic and Therapeutic

The open surgical exploration of the extremity arteries is fast becoming a lost art along with the physical examination. In the setting of acute limb ischemia, the first decision in my mind is: was this an embolism? The presence of arrrhythmias, cardiac shunts, and aneurysms may suggest this, the next question is did this patient have a prodrome of limb ischemia related symptoms and history of atherosclerosis. The fact is, you have about 4-6 hours to return blood flow before irreversible neuromuscular damage sets in, maybe less if important collaterals are lost. Choice of procedure then devolves to choices about the most expedient methods for returning blood flow to the extremity, and between endovascular procedures and open surgery, it is rarely possible to manage significant clot burden with endovascular methods without adding the burden of procedural time. These considerations are balanced by patient risk. If the patient cannot tolerate general anesthesia, it is still possible to operate under local anesthesia. Otherwise, one is faced with choices like stenting across clot or common femoral artery. The algorithm is simple -ensure inflow, thrombectomize outflow, check for backbleeding, restore flow, check flow, repeat as necessary downstream. Fasciotomy as needed and close the skin if you can.

Endovascular options deal with the basic physics of trying to pull clot of varying consistency through a small lumen over a long length while not pushing emboli. The needs are simple -a low profile, cheap, over the wire solution for evacuating clot without embolizing nor injuring the patient on a 100cm and 150cm length catheter. Cost wise, open surgery always beats any endovascular option if wound complications of open surgical exposure are avoided. Both methods can’t cover themselves if open fasciotomy wounds keep the patient in the hospital for weeks. The fact is, we already have this magic system in the catheters that we already have on the wall, albeit, they don’t work particularly well if you are dealing with Parmesan, but none of the systems do. I recently declotted a graft fistula with just 6F sheaths, a regular #3 Fogarty ballon, 6mg of tissue plasminogen activator, and was able to salvage the blood and return to the patient.

Conclusion

Vascular surgeons should have as many words for clot as Eskimos purportedly do for snow. There is no one solution to a problem, but all the tools must be available to the vascular surgeon. Ironically, only the simplest are needed most of the time.

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skunk works techniques Technology Uncategorized

Distraction free writing used to be the norm with technology

IMG_0645

Distraction Free Writing: Portable, Disconnected, AA Battery Powered

Distraction free writing has been a buzzword. It used to be the norm with computers by their limitations and design to focus you on writing. Today, technology is increasingly put in front of you to entertain and distract. The problem for students and writers is that your computer and phone are gateways to music, video, and communication in ways that were only dreams twenty years ago. The key elements of distraction free writing are a decent keyboard, extended battery life, simple interfaces, lack of connectivity, and   absence of party line operators. Each of these elements formed the core of our computers back in the 1980’s, when computers were rarely networked, they were all monochrome, and your words were all that you saw. This desire is driving the market for distraction free writing software and hardware, but you can find ways to create your own portable distraction free writing tools without dropping a fortune. And distraction-free writing is also intrusion-free -something to consider in today’s shifting privacy boundaries. At the end, the best distraction free options may be in reconsidering decades old devices that may be picked up cheaply used or at greatly reduced prices for new. Most current devices are made to last about a thousand recharges, and struggle with purposeful obsolescence. You may find that there are many fine older options that will suit your writing needs while greatly increasing your productivity while avoiding costs.

Consider the keyboards we had back in 1985. They were all mechanical spring keyboards which made a nice click sound. Writing was a tactile pleasure. This was in contrast to the membrane based keys seen on games and toys, and mistakes like the PCjr. You see them today as controls for microwave ovens. The moving keys send a message of accomplishment to your brain. Despite this, flat keyboards with no physical component  are still being thrown up to see if they would stick. The smartphone keyboard on the first iPhone killed the physical ones on Blackberry and the Treo’s after all. Manufacturers are still experimenting with flat keyboards such as on the latest Yoga Book’s e-ink keyboard, and the upcoming Microsoft Surface Duo devices.

IMG_0649
flat screen based keys like on the latest Yoga Book takes some getting used to

These software and touch display based keyboards rely on spelling correction and ultimately constant connectivity to minimize error. The push for ultra-portability means dispensing with the original mechanical keyboard which was descended from electric typewriters like the IBM Selectric. This resulted in the terribly mushy, mass produced keyboards introduced in the 1990’s, getting ever worse. The high point of this design viewpoint was introduced in the 2015 MacBook and recently retired in the 2019 Macbook Pro when Apple realized everyone hated typing on superflat keys meant to accommodate flatness over functionality. There is a welcome movement back to reasonable keyboards. I would even claim that the persistent life and value of the Thinkpad line is the focus on the keyboard that remains preserved after IBM sold it to Lenovo. The new-old keyboard on the 2019 MacBook Pro 16’s are a concession to the realization that typing is a core function of these machines.

There is a push back as writers, office workers, and gamers have created a market for mechanical keyboards. These are usually Bluetooth connected devices, and typically paired to tablets for writing. Unfortunately, separate keyboards connected to tablets are not as portable as a laptop.

QWERKYwriter is a retro mechanical keyboard for tablets but try taking that onto an airplane

I would argue that laptops are not as portable as they could be. The Freewrite (link) was designed with writers in mind as an update to electric typewriters with cloudbased file management and an e-ink display with days of battery life on a single charge. I almost bought one but the small display and the relatively bulky size kept me from springing. I have ordered a Freewrite Traveler (link) which is their mini-laptop version, but since I ordered one last spring, it has remained vaporware with its delivery date pushed back from summer 2019 to spring 2020.

Battery life is a sore point for me. Laptops are now expected to be wonderful if they exceed 8 hours of battery life, but I remember that the original portable computers like the Radio Shack 100 series could go days on AA batteries. Writing appliances were introduced in the 80’s including electric typewriters with single line LCD displays and single file memory which would allow you to compose and edit. I had such a device from Japan in high school that had a four line LCD display, built in thermoelectric (fax paper) printer, and battery life that went several days on 4 AA batteries.

By using computers and smartphones, which function as portable televisions and multi-function, shopping kiosks which use Watts of power, the trade off is battery life and constantly worrying about plugging in for a recharge. We forgot the days of battery life and are happy with 8 hours. The battery power bar is terribly distracting for me and I tend to stop working to find an outlet to recharge when it inevitably drops and when my productivity is nearly always highest. If I’m traveling, this means carrying the power brick, another injury to this one who remembers AA battery powered writing tools.

In 2017, the Samsung Galaxy Note 7 was famously recalled after spontaneously combusting and were banned from airplanes. All Lithium batteries must now be hand carried. Just recently, I was told while checking in that Apple Macbooks could not be turned on during flight because of heating issues. This is a consequence of the greatly increased energy densities of Lithium cells and their chemical volatility. AA batteries and their nickel metal hydride (NiMH) rechargeable variants suffer from no such problem.

Even with great battery life, you have to remember most of that power, and therefore bulk and weight of the Lithium batteries is devoted to painting vivid colors on the screen, communicating via radio signal to the world, and keeping dozens of apps updated on your activities, and not to writing.

The Lithium battery which can power a car because of its energy density is overkill if all you want is to write. The modern computer operating systems, Windows, MacOS, iOS, and Android, are all over-powered for the simple act of preserving words. Consider the lowly text file to a modern Word file. The text file for a novel might take kilobytes of memory, but the same Office Word file is measured in megabytes -thousands of times bigger. Try emailing a fully formatted Word file through your corporate firewalls if it exceeds your company’s limits on attachment file sizes. The size and complexity of information that is exchanged burns power. Compare that to the notes you might write onto paper. The few microcalories used to power your neurons and move pencil on paper, the motor and optics circuitry processing the information at a speed suitable for your ape brain.

My friend and early mentor, Professor David Tilson, refused to relinquish his DOS based word processor even well into the Windows era. And I understood. The monochrome and monotype letters forced you to look at the words and not the style of the words. While I admire Steve Jobs, and his introduction of fonts to our everyday lives, the ability to shape the look of your writing intrudes on its composition. Monochrome does not mean monotonous, and modern distraction-free software efforts like IA Writer embrace simplicity. The emergence of dark mode is another effort at rolling back the clock. When you enable it for your iPhone, it reaffirms the utility and critical need for focus and simplicity. Do you need millions of colors or just letters on a simple background? While you can change the color setting of your laptop screen or your writing software, the ultimate in monochrome experience is an e-ink display.

The e-ink display is what you see on Amazon Kindles. Originally meant for low power usage, high contrast functions like in store signs, e-Ink is currently used for e-Readers, although there is a niche market for e-ink based displays and tablets which do offer the low power hi contrast display perfect for a focused writing work station – you can find them on Amazon and eBay. Unfortunately, because these e-Ink tablets are run typically on Android, there is no escaping the internet on these, and because they do so, their battery lives are not that much different from standard tablets. What the we need is for Amazon to gift the writers of the world with Bluetooth or wired keyboard functionality to their Kindles and offer a text writer that can be synced to their cloud..

What the we need is for Amazon to gift the writers of the world with bluetooth or wired keyboard functionality to their Kindles and offer a text writer that can be synced to their cloud.

The constant need for connectivity drives software and hardware inefficiency. Writing requires intimacy and privacy. Just as you cannot write while engaged in a shouting match with someone, you cannot write with notifications of arriving messages, pictures, and videos. I cannot write while watching a movie or listening to certain music, but all of these distractions are baked into the function of modern computers and smartphones. This uses up battery life. The devices are in a race to maximize the battery and screen size at the cost of purpose and meaning aside from commerce.

Party line operators were a feature of the early telephone systems. Your locality was serviced by an operator that routed your calls and inevitably your conversations were open to intrusion both intentional and unintentional. When all your work is kept on a cloud server, it really is no different. And it isn’t that hackers that may take all your work. My generation grew up with the Cold War, and its dark tales of thought crimes and writers imprisoned for samizdat -ideas forbidden by a state entity. In a time when your social media is a subject for governmental and not just consumer interest, returning to off line options is something to consider seriously. The meaning of party line operators is in this context wholly changed.

The one feature of cloud based options is the convenience of accessing it across all of your devices. But are you really going to be writing on your iPhone, then on your desktop, then on your laptop, then from an airport kiosk? Your file can be lost during the sync process or changed to a competing version from another computer you were working on. And goodbye work if you get hacked or if your cloud service shuts you down or out. While you write, you have to keep a local version and back up to a nonvolatile storage option.

Not connecting to the internet saves you battery life. It also frees you from taking deep YouTube dives into funny cat videos or answering emails or Facebook posts. The stillness you need to just write is difficult to achieve with a modern laptop, tablet or smartphone. It can be attained with these older devices which people in the know still value decades after they left their boxes. I suggest these options if you are thinking of trying a focused writing appliance (a typewriter!).

Option 1: King Jim Pomera DM100  (link) is best described as a writing appliance designed in Japan adapted for the English speaking market. It is a sleek thin portable that allows one to type words unencumbered by internet. The files on it can be transferred to another computer by Bluetooth, and to smart phones by QR code which is cool. It runs for days on AA batteries, and has a backlit monochrome LCD screen. It is priced on th high end at 392.61, but receives the best rating on Amazon which to me is a 4.5. I never come across 5 star reviews that aren’t fake. One reviewers comment that the keyboard is cramped and takes getting used to. It can be used as a Bluetooth keyboard and stand for iOS devices.

Option 2: Neo 2 Alphasmart Word Processor with Full Size Keyboard,, Calculator

The Alphasmart Neo2 (link) was the last of a line of writing appliances put out by a pair of former Apple engineers who wanted to provide affordable word processing options on a full mechanical keyboard. The Neo2 is the most available and apparently the most usable, allowing one to type out hundreds of pages and transfer to a computer via USB connection. The screen is an LCD screen like on a calculator. The killer feature on this device is nearly forever battery life on AA cells. It has a rabid following of professional writers who appreciate the pared down experience for productive writing. It achieves that perfect 4.5 star rating. This is for a device discontinued in 2007 and sells for about 40-50USD in used condition. Reviewers rave about turning it on and instantly being able to type without bootup, and avoiding distraction by email, notifications, social media etc.

Option 3: Psion Series 5MX

The Psion Series 5MX represented the apex of portable computer design in the late 1990s. It was a computer made from the ground up from circuits, hardware, operating system, and apps by British engineers and it was a thing of beauty. Made in the late 1990’s, this device’s killer features, long battery life via AA cells, ultraportabiity, and lack of easy internet access puts it in a separate class. Not everyone like the keyboard, but I have long been able to type on it without difficulty with average to large sized hands. I had one during residency in the 1990’s and it followed me into fellowship. Before EHR, I composed full consultation notes and H&Ps on it and filed them on my password protected CF drive for later retrieval and update for frequent flyer patients. I picked up a pair of these for about 90USD from the Netherlands, but the going priced varies from about 70 to 200USD for a used one in good condition. New ones pop up but they go for nearly their original price -they are that good. I suspect I got a deal because they were Ericsson MC218, a Swedish licensed clone.

It has a compact flash drive, and with the save as text file function in the built-in word processor which works fast and reliably, it is possible to back up to a nonvolatile memory (the CF drive) and transfer to a regular computer. The one caveat is that the maximum size of CF drive it will see seems to be 128mB -that is megabytes which is hard to find. In certain older industrial machinery, instructions are uploaded via CF cards of these size, and so these cards are available on Amazon. Or look in a drawer for an old unused CF card.

I wrote this post on the Psion, and never once looked at emails, social media, or Youtube.

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I wrote this post on the Psion, and never once looked at emails, social media, or Youtube.
Categories
acute limb ischemia aortoiliac occlusive disease (AIOD) innovation limb salvage PAD skunk works techniques ultrasound

The shunt as temporary bypass -a modest proposal

The rise of cardiopulmonary bypass life support has also given a rise to the need to keep large, obstructive cannulas in femoral arteries. ECMO cannulas are often kept in for days, and it is not uncommon to discover limb ischemia and infarction relatively late. This can be avoided by placing a distal perfusion cannula to shunt blood to the leg early in the ECMO process. The ECMO cannulas have a convenient side port to send a little flow to a 6F sheath placed in the femoral or popliteal artery. This is an established technique (reference 1, sketch below), and it works despite the modest flows achieved because it does not take much to keep the leg alive. These patients are not walking, nor are they need to heal leg wounds, so just enough blood flow means something just a little more than what they get when the common femoral artery is completely occluded by the life support cannulas. What is fascinating to me is that these shunts can pptentially help to save limbs when used as temporary extracorporeal bypasses when definitive vascular surgical care is not immediately available.

brachial to femoral shunt sketch

 

When I was a medical student, I took on a research project after my first year where I had a Langendorff preparation of a rat heart (below).

langendorff prep in MRI
an isolated, perfused, beating rat heart placed in a superconducting magnet for NMR spectra acquisition 

My project was to take a rat heart and keep it alive, beating, and even working, through a perfusion apparatus and place this inside a superconductive magnet to obtain Phosphorus nuclear magnetic resonance spectra -intracellular metabolism data including concentration of ATP, intracellular pH, and ATP/ADP ratio. While the project was successful -I am quite proud to have been the only person at Columbia to have successfully acquired NMR-S data with living beating heart, I moved on to other interests and took away this concept: with oxygenated, glucose enriched, isoosmolar fluid perfused at arterial pressure, any organ can be kept alive, possibly indefinitely, including a brain which only recently others have found possible (reference 2) in reputable scientific circles, but the the Nature publishing Yalies were scooped by the Simpsons decades ago (below), and maybe Mary Shelley centuries before,

simpsons head

This is the simple idea. Revascularization is keeping the target vascular bed alive by delivering oxygenated blood. With a shunt, it could be little, it could be a lot, but it certainly is better than zero, and even a little can buy you time.

The breakthrough that I had was several years ago, a patient arrived from another hospital with an Impella pump which did not have a side port like an ECMO cannula. It is a large catheter that augments cardiac output and in the patient that I was asked to see this patient as their leg was cold and pulseless. Their cardiac output was very poor, and they were sustaining an augmented systolic pressure in the 90’s. There was no way to get this patient to the operating room for a revascularization of any sort. It did strike me that the patient had the misfortune of having catastrophic heart failure in the absence of significant athersclerosis and had normal brachial arteries. After discussing the ramifications with the ICU and family, I placed a brachial artery 5F cannula, and connected it to a 5F sheath I placed in the superficial femoral artery below the occlusive common femoral sheath (figure below). A doppler on the tubing connecting the two cannulas confirmed flow and the patient’s left hand maintained a pulsatile oximetry waveform. The leg pinked up and eventually there was a signal in the foot. This managed to perfuse the leg which did better than the patient who succumbed to multiorgan failure from heart failure. The leg did great.

Which leads me to these thoughts. Most hospitals are good at diagnosing large vessel occlusion via CTA. Most hospitals have doctors who can place arterial lines with ultrasound guidance. In the instance of aortoiliac occlusion or femoral occlusion from thromboemboliem, time is a critical limiting factor to limb salvage. Many hospitals do not have vascular surgeons. Many hospitals transfer these patients with a heparin drip but in the ischemic condition. Transfer arrangements may take hours. Why not ameliorate this situation by having an appropriate physician -an anesthesiologist, an intensivist, an EM physician, place an ultrasound guided radial or brachial arterial line, connect to arterial line tubing to a dorsalis pedis arterial line. Tape it all down on the patient after confirming flow (crude sketch below). This would be better than the three extra hours of ischemia the patient gets hit with on transfer. No one would transport a donor kidney without adequate perfusion and protection, but dying legs get transferred all the time with established warm ischemia. If done well, it might turn an emergency procedure into an urgent, semi-elective one. Have the vascular surgeon video conference in to confirm the absence of blood flow and appropriateness of temporary shunting.

radial to dp shunt
radial artery to dorsalis pedis artery shunt

If we are to live in  a world with less vascular surgeons, then the radius of survival has to be extended with use of technology and simple ideas such as this. Comments are welcome.

Reference
1. Foltan M, Philipp A, Göbölös L, Holzamer A,
Schneckenpointner R, Lehle K, Kornilov I, Schmid C, Lunz D. Quantitative assessment of peripheral limb perfusion using a modified distal arterial cannula in venoarterial ECMO settings. Perfusion. 2019 Mar 13:267659118816934. doi: 10.1177/0267659118816934.

2. Vrselja, Z., Daniele, S. G., Silbereis, J., Talpo, F., Morozov, Y. M., Sousa, A. M. Mario, S., Mihovil, P., Navjot, K., Zhuan, Z. W., Liu, Z., Alkawadri, R., Sinusas, A. J., Latham, S.R., Waxman, S. G., & Sestan, N. (2019). Restoration of brain circulation and cellular functions hours post-mortem. Nature, 568(7752), 336–343.

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AAA EVAR hybrid technique mycotic aneurysm ruptured AAA skunk works techniques training

The Hands of a Surgeon

My partner, Lee Kirksey, Vice-Chair of Vascular Surgery, just got a paper on-line (link) about the curiously increasing volume of open surgical repairs we were experiencing from 2010-2014 at the Cleveland campus of the Cleveland Clinic. When I joined in 2012, my impressions at that time were mostly the paucity of straightforward EVAR cases that I had seen in private practice, and the high prevalence of stent graft explantation, infected aortic grafts, and open aortic aneurysm repairs (OAR) for juxtarenal and thoracoabdominal aortic aneurysms for nominally high risk patients. My TAAA muscles had atrophied during my years out of fellowship and I eagerly took the opportunity to recruit the help of my partners and scrub in on these cases with Pat O’Hara, Jean Kang, Dan Clair, Ezequiel Parodi, and Lee Kirksey. It is without any shame that I sought out not just extra expert hands, but interrogated these experts for different ideas and approaches, and absorbed feedback. At the time, I was ten years removed from graduation, a full-fledged vascular surgeon who thought he could do any operation put before him. I cannot imagine the thoughts churning through the head of a recent graduate faced with the choice of taking on an open aortic operation with only 5 cases under their belt, referring the case on to the regional tertiary center, or trying to McGyver an endovascular solution. I contributed probably about 35-50 cases to this paper, but the outcomes were a collective effort. Even today, I will run cases by Sean Lyden, Christopher Smolock, or Lee, if only for the company and gossip.

“We explain this distribution of cases as a function of several factors: a unique, broad regional quaternary referral practice whereby patients with complex aneurysmal disease are referred to our institution; an institutional practice evolution resulting from a critical analysis and understanding of EVAR failure modes that lead to explantation, thus generating a different perspective in the EVAR vs open decision-making process; a parallel high-risk IDE fenestrated graft study; a historical willingness to accept all physician and self-directed patient referrals (ie, a willingness to manage more complex cases); and a published expertise in the area of EVAR device explantation with an annually growing volume of commercial device removals” -from El-Arousy et al.

Reading through that paper, I have come to the conclusion that the increasing open aortic volumes at the Cleveland campus has as much to do with the ongoing retirement of experienced surgeons regionally as it does with the ability to attract these cases. Loss of these surgeons has a cascade effect like losing a species in an ecosystem. The operating rooms forget where the OMNI retractor is because nobody asks for it anymore. The ICU’s are no longer familiar with the ebb and flow of the postoperative open aortic operation. The floors lose institutional memory of the care of these vascular patients as the stent grafts and interventions go home within 48 hours, sometimes the same day.

If you were a vascular surgeon born before 1970, your approach to the scenario of the ruptured abdominal aortic aneurysm may differ substantially from that of surgeons born after the Carter administration. Most of my cohort, Gen-X and older, feel comfortable applying some betadine, opening the belly and placing a clamp. Those younger than us have told me they feel more comfortable putting up a large balloon and deploying a stent graft. In this generation, it is normal to call a general surgeon to decompress the abdominal compartment syndrome and manage the abdominal vacuum dressing. For our generation, the giant industrial robot arms and 80 inch monitors creates a barrier to the problem at hand, and gathering all the extra staff after hours and on weekends requires the logistical skills of a wedding planner.

We prefer an operating table, a willing anesthesiologist, a cooler full of O-neg blood, Prolene and a graft, strong suction, and an extra set of hands. The data suggests either method is equivalent in outcome, but I would argue that depending on the circumstance, there is an optimal method for that patient and you have to have the ability to do either open or endovascular or some hybrid combination. Unfortunately, it is clear that open vascular surgery is year over year diminishing, and and it might not be so great when we start rupturing our aneurysms.

The open approach is preferred because we got good at it by doing a lot of these cases. Your hands -it becomes natural to change the course of the disease and the fate of the patient with your hands. One of the things you lose with a wire based approach is the tactile feedback from the organ that you are treating. Yes, there is a subtle feedback from the flexible tip of a Glidewire, but that’s missing the point. The thing that is rarely considered with open surgery is the tactile aspects of operating.

Your fingers are your point of care ultrasound. As an intern, one of my earliest tasks was reaching in through a 2cm incision with my index finger, feeling for what I would describe as a rotten shrimp, and delivering it out by hooking my distal phalanx around its base. Adhesions were rubbed like money between finger and thumb to judge if you could bovie through it. If you felt a sliding sensation, it was mucosa to mucosa and you looked for another spot to cut. Into my fellowship which could be called the triple-redo, no-one else wants to do-, difficult vascular operations fellowship, the pulse or the plaque felt under the finger would guide me to carve away scar tissue from blood vessel, visualizing the feedback from the fingers. In a rupture, with the belly under a dark mire of blood, there is no seeing, only feeling. Your hands reach into the lesser sac or transverse mesocolon and strangle the aorta -your fingers while clamping, feel and avoid the caudate lobe, the NG tube in the esophagus, and split the crura of the diaphragm like a pick pocket. Once the pulse returns as anesthesia refills the tank, you scratch free the aorta with your thumb and forefinger, then slide the jaws of the aortic cross clamp over your fingers and against the spine and clamp. This takes about 60 to 90 seconds (link).

When a patient is bleeding out, this is the way to control the bleeding. In practice, no amount of rehearsing for getting a patient into a endovascular suite, getting airway and access, swinging in the industrial robot arm, and getting everyone into lead aprons, sending up wire, placing a 12F sheath and an aortic occlusion balloon, will be satisfactorily smoothly and efficiently as a STEMI or STROKE alert. The rAAA is for most hospitals, unless you are in Seattle, a once in a while occurence. Many more people can find a scalpel and an aortic clamp than they can find a 32 inch aortic balloon, a stiff exchange length wire, and a 12F sheath.

When a patient presents with a slowly bleeding, contained rupture, there is time to assemble the teams required for an endovascular repair, and for opening and decompressing the abdomen, for anesthesia to get IV’s, central lines, arterial lines, and order crossmatched blood. One has the time to get and review CT scans and choose grafts. One can even do things backwards, debranching after securing the leak (link) with a stent graft. The luxury of time should signal to you that the endovascular option is the preferable route, as all the advantages of minimally invasive repair are possible. Rural hospitals sending patients two hours by ambulance or arranging for a helicopter -this is the great filter through which those likely to survive make it into the endovascular suite. These patients do great with EVAR, because everything moves more or less like a routine elective EVAR.

The setting up the operating room for tackling rAAA is quite simple. Keep everything nearby. Nothing should ever be stored out of sight, retrievable only by arcane codes whispered in the ears of people down in the basement or across the street. Amazon gives itself a day to get that gadget to you, but the rupturing patient does not have the time to have a 28mm stent graft ordered by looking up a Lawson number, finding the materials person in the faraway room to find it, running it over a city block. The stuff has to be next to the OR. Every scenario is unique, and the best planning is assuming no one person knows where everything is but everything is close at hand -major vascular sets, retractors, C-arm, cell saver, stent grafts, open grafts, balloons, cardiopulmonary bypass -every gewgaw is few steps away. The inventory is what you see, because if you can’t grab it, it does not help the hemorrhaging patient.

If you are a vascular surgeon born after 1980, it is likely that you may have trained in a 0-5 residency and all the old people harumphing about the old ways seem biased. Rather than being rational about their awful upbringing, the old people seem to suffer from Stockholm Syndrome, turning from victims of a harsh and brutal system inherited from the original, Halsted, a cocaine addict, to willing collaborators now mooning about the good old days of every other day call and 120 hour work weeks.

There might be a growing suspicion about advocating for open surgery when fewer people can perform it. One of the truisms of surgery is if only one surgeon claims to be able to do a rare operation with great results when everyone else abandons it, like venous valve surgery or robot assisted mastectomies, it can mean that surgeon might be uniquely talented or shamelessly selling something. It is a shame that open vascular surgery is devolving into that category of arcana, like the Jedi. I have no doubt that the last open vascular surgeon will be a reclusive, bitter, wild eyed hermit like Luke Skywalker was in episode VIII, if we let it get that far.

Bald eagles were saved from extinction. The methods of species reclamation may be what is needed to save open vascular surgery. Financial metabolism drives behavior, and there must be recognition of the time and dedication required to perform good open vascular surgery in the form of increased RVUs and reimbursement. The surgeons retiring in their mid 60’s with straight backs and steady hands need to be incentivized to stay around and coach the next generation in the ways of the Jedi. Call it the master surgeon designation. Every 0-5 graduate needs to focus on getting 100 leg bypasses, 50 carotid emdarterectomy, and 25 open aortas within the first five years of practice with a master surgeon if they did not get this experience during training. Like dead Jedi, it would help even if they were just virtually present, shimmering on Facetime in their (bath)robes to go over planning and approaches, but being physically present and reimbursed for it would make the most sense.

There is always self service in any human activity. One mildly prominent vascular surgeon that I have come across is famous for saying he did not have a vascular fellowship because he did not want to train his competition. It is easy for the fifty somethings to sit and proffer their open skills and profit from its scarcity but it goes against decency to not pass on this collective body of hard won knowledge and skills. There must be stewardship of this great thing we do, this honorable and treasured endowment.

Of the concrete ways we are trying is creating a network of advanced open surgery capable surgeons regionally organized by Martin Maresch, capitalizing on social media and electronic communications. Here at CCAD we are in the organizing phase of a vascular residency, and I very fortunate to have Houssam Younes join us as he shares my interest in surgical education and open vascular surgery. We are contemplating a non-accredited fellowship. We have general surgery residents coming through our service as well as medical students.

One of my mentors told me, “I can train a monkey to do cardiac surgery,” as he was training me to do cardiac surgery. And he was right. The final comment I have is you have to demystify surgery, take away the Instagram perfection, the romance, and list in practical terms the toolkit of maneuvers that form the component parts of all operations and propagate it. Let us not kid ourselves. The technical skills of surgery can be taught to anyone. The Mayo brothers were performing surgery as teenagers before medical school. The knowledge and experience and judgement -that varies as much as people vary and we have a curriculum for that, but the physical acts of surgery need to be taught starting at the medical school level. Standardized drills and exercises need to be created so that proficiency can be metered.

“The individual per trainee OAR volume did not decrease during this period. In the training program, the use of “component separation” (separation of each
operation into discrete, instructionable steps that facilitates trainee mastery) is integral to instruction of open aortic aneurysm repair techniques and permits the
trainee to master all of the technical exposure and repair skills necessary to address and to manage both straightforward and complex aneurysm anatomy. Component
separation is essential to maximize trainee experience across all levels” –from reference 1

Here is my list of things a trainee must accomplish by the time they graduate from a vascular residency or fellowship.
1. Tying knots with gloves on with 6-0 Prolene inside a pickle jar without lifting or moving a 12 ounce lead fishing weight to which the suture is being tied, fast, one handed, two handed, left and right handed.
2. Holding forceps, needle holders, and clamps
3. Correct operation of the OMNI retractor, Weitlander retractor, Balfour retractor, Thompson retractor
4. Incise skin through dermis through correct depth and length with both #15 and #10 blade
5. Open the abdomen through midline and flank incisions and close these incisions
6. Harvest saphenous vein
7. Vascular anastomosis on a table, inside a pickle jar, inside a short Pringle’s can
8. Dissection of adhesions and scar tissue around blood vessels and organs
9. Dissect and expose the common femoral artery via vertical and oblique incisions and close these incisions
10. Dissect and expose the carotid bifurcation, left and right side, and close these incisions
11. Dissect and expose the tibial vessels in various parts of the leg and foot
12. Dissect out the brachial artery at the elbow
13. Dissect out the axillary artery and vein below the clavicle
14. Dissect out the axillary artery and vein from the axilla
15. Dissect out the subclavian artery, vein, and brachial plexus above the clavicle
16. Dissect out the arm veins
17. Dissect out the iliac artery via a lower quadrant pelvic retroperitoneal exposure
18. Dissect out the abdominal aorta via midline laparotomy
19. Dissect out the abdominal aorta via retroperitoneal approach
20. Dissect out the thoracoabdominal aorta via a thoracoabdominal exposure
21. Dissect out the popliteal artery via suprageniculate, infrageniculate incisions and prone position
22. Dissect out the inferior vena cava
23. Dissect out the iliac veins
24. Harvest deep femoral vein
25. Temporal artery biopsy
26. Endarterectomy of carotid, femoral artery, any artery with patch angioplasty
27. Exposure and control of supraceliac aorta, suprarenal aorta for clamping
28. Exposure and control of thoracic aorta
29. Exposure and control of the great vessels via sternotomy and supraclavicular incisions
30. Exposure and control of the vertebral artery
31. Safe removal of vascularized tumors
32. Amputations of digits, legs and arms up to pelvis and shoulder
33. Exposure and control of radial and ulnar arteries
34. Hand surgical techniques of exposing arteries, tendons, and nerves in forearm and hand
35. Plastic surgical techniques of skin grafting and basic rotational flaps
36. Fasciotomy of arms and legs, hands and feet.
37. Exposure and control of celiac axis
38. Exposure and control of superior mesenteric artery
39. Exposure and control of left renal vein
40. Exposure and control of hepatic veins, portal vein
41. Exposure and control of renal arteries
42. Exposure and control of profunda femoral arteries
43. Safe removal of spleen
44. Transabdominal retroperitoneal exposures of the abdominal aorta and inferior vena cava
45. All of the above in a reoperative field
46. All of the above with limited visualization and by sense of feel only
47. Laparoscopic and thoracoscopic techniques
48. Orthopaedic surgical techniques of myodesis, bone grafting, precision osteotomies, infection control, external fixation, spinal exposure
49. Safe resection and anastomosis of bowel
50. Drainage of infection
51. Intensive care of SIRS, MOFS, CHF, Septic shock, postoperative fluid shifts
52. Nonsurgical and surgical management of lymphedema, seromas, and edema
53. First rib resection
54. Spinal exposure
55. Organ harvest and transplantation
56. Planning of complex open, hybrid, and endovascular procedures

Every year, it is apparent that endovascular options suffer from some flaw when outcomes are studied beyond 2 years, but progress will march on in that sphere. It has to. The loss of open capable surgeons to early retirement is accompanied by overapplication of endovascular techniques at least partly due to the lack of knowledge of these open surgical options and achievable good results and partly due to financial incentives. The solution lies in redistribution of reimbursement to open procedures and creation of open surgical fellowships and identifying and empowering mentors who still walk among us.

Categories
Commentary complications imaging limb salvage PAD popliteal artery entrapment syndrome techniques

Zebras, not horses: popliteal artery entrapment syndrome

mega mushroom
Adding a vascular surgeon to a hospital is like eating one of these. It turns Mario into Mega Mario. Vascular surgeons turn community hospitals into tertiary care centers.

Recalling the medical school adage, “when you hear hoofbeats, it’s probably horses, not zebras,” it is critical to think about rarities down on the differential list whenever you come across a patient. Vascular diseases suffer from inadvertent obscurantism arising from its absence from medical school curricula such that common disorders like mesenteric ischemia and critical limb threatening ischemia are frequently missed by even experienced medical practitioners. Vascular zebras are even harder to pin down because many experienced vascular specialists practice for years before they encounter, for example, adventitial cystic disease or dysphagia lusoria with a Kommerell’s diverticulum. Even so, real patients have these disorders, and we are all subject to inexperience bias -the feeling that something does not exist until you see it. You may completely miss something staring at you in the face or worse, deny its existence.

The patient is a middle aged man in his 50’s who aside from mild hypertension had no real risk factors. One day, at work, his right leg stopped working. He developed a severe calf cramp and the forefoot was numb and cool. He went to his local hospital and the doctors there appreciated the lack of pulses in the right leg and got a CTA, of which I only had the report which found a right popliteal artery occlusion.

The next morning, as he had signals and was not having rest pain, his doctors discharged the patient on clopidogrel and scheduled for angiography and stenting, per patient. As his debilitating claudication did not go away over the weekend, he came to our emergency room. While he had no rest pain, he did have minimal walking distance before his calf muscles seized up. On exam, his right foot was cool and cyanotic, with intact motor function and sensation. There was a weak monophasic posterior tibial artery signal. Bedside point of care photoplethysmography showed dampened waveforms (below).

dppg.png
Look at the blue line. The waveforms are dampened in the ischemic foot.

Because he did not bring his CT, I repeated the study. I have written extensively on the need to be able to share CTA studies without barriers. After his study, I brought it up on 3D reconstruction software.

paes.png

It clearly showed a Type II Popliteal Artery Entrapment affecting both legs (CTA images in series above). Stenting it would have failed.  I spoke with the patient about operating the next day. The plan was popliteal artery exploration and thromboendartectomy with myotomy of the congenitally errant medial head of the gastrocnemius muscle. The patient was agreeable and I took him to the operating room for a myotomy and popliteal thrombendarterectomy in the prone position. The medial head of the gastrocnemius muscle went over the  popliteal artery and inserted laterally onto the femur.

pop opened.png
Endofibrosis, cut medial head of gastrocnemius muscle to right of distal clsmp

The artery was opened and while there was fresh clot, the artery showed signs of chronic injury as evidence by endofibrosis which pealed off. Pathology showed to be fibrotic in nature.

04-SP-19-4119 Trichorme stain showing fibrous tissue as green
Trichrome stain showing chronic endofibrosis

The artery was repaired with a pericardial patch and flow restored to the tibials, not all of which were completely patent.

pop patched.png

The patient was discharged after about a week and will be scheduling repair of his contralateral popliteal artery entrapment.

The vascular surgeon has a vital role in a hospital’s medical ecosystem. One time, I heard hospital administrator say that with the advance of endovascular technologies, the vascular surgeon would become an expensive, redundant luxury easily replaced by the overlapping skillset of radiologists, cardiologists, general surgeons, trauma surgeons, cardiac surgeons, nephrologists, neurosurgeons, neurologists, podiatrists, infectious disease, and wound care specialists. When I identify these zebras, these rare diagnoses, I am neither replacing all those aforementioned specialties, nor having special insight unavailable to the uninitiated. I am keeping my eyes open. In a non-smoking, active, otherwise healthy and employed middle aged man with no cardiac history, it is very strange to have isolated popliteal occlusion with otherwise pristine arteries throughout the rest of the CT scan. That is a statistical outlier. People who occlude blood vessels in this fashion usually have more comorbidities, usually are older, and usually have more atherosclerotic disease burden. While not quite like the teenager who presented last year with the same diagnosis (after a month of misdiagnosis and delayed treatment), the cleanliness of the arteries elsewhere in the body was disturbing to me. This puts me on a zebra hunt and not the usual horse roundup.

A hospital needs vascular surgeons in the way that America need the US Marine Corps. Every decade, there is some congressional movement to see how the USMC, which has fighter jets, tanks, planes, aircraft carriers, helicopters, and riflemen, can be phased out because it seems to duplicate the services of the Navy, Air Force, and Army, and every generation a conflict proves these arguments wrong. Individuals who know things broadly and deeply, who can do many things across specialty lines, work from head to toe, and whose specialty is to customize solutions to complex problems is the special quality that is the difference between tertiary hospitals and quaternary hospitals. While these qualities are goals within Vascular Surgery, it is a generalizable goal for anyone working in healthcare. My favorite professor in medical school was Dr. Harold Neu, chair of infectious diseases at P&S. He knew everything and was interested in everything and took every moment in the hospital to increase his knowledge a little more. That’s how and why I diagnosed a case of schistosomiasis earlier this year -the upper abdominal pain was not from a coincidental aortic aneurysm, but the fellow did swim in the Nile.

I texted Dr. Sean Lyden, my former boss and partner at the Cleveland Clinic main campus, if there was any situation where an asymptomatic popliteal entrapment who had gone over 50 years of life without complications could just be watched -it was a question from the patient actually. Dr. Lyden treats popliteal entrapment weekly and maintains a clinic specializing in popliteal artery entrapment (link). One of advantages of working in vascular is that the community is small and highly accessible, and I have a group of living textbooks on speed dial (that term pegs me as antique). There is an active social network of vascular specialists and the SVS maintains SVS Connect (link) for posting and discussing difficult questions. Despite the horrible hour that he received the text (“What’s the matter? Are you in trouble?” he asked) because of the time differences between Abu Dhabi and Cleveland, he answered, “no.” Sorry, Sean, for texting you at 4 in the morning.

When you look for four leaf clovers, and you have never seen one in your life, the moment you find one must be transformative. I have never found one, but I keep my eyes open, lest I trod on one.

 

Categories
aortic dissection CTA EVAR taaa tbad techniques TEVAR thoracabdominal aortic aneurysm training type b aortic dissection visceral malperfusion

Complicated Aortic Dissection Talk

A basic recipe for treating complicated aortic dissection

#aorticsurgery #tevar

Categories
acute mesenteric ischemia aortic dissection bypass chronic mesenteric ischemia complications ruptured AAA taaa tbad techniques TEVAR thoracabdominal aortic aneurysm training type b aortic dissection visceral malperfusion

Life imitates social media: a ruptured type V thoracoabdominal aortic aneurysm or IT saves a life

ARTERIAL (2) (2)
Type V TAAA Rupturing into Right Pleural Cavity

It was only last month when I came across a post of an aortic aneurysm in a difficult spot (link) and I couldn’t help chiming in some comments. Reading it now, I sound insufferable, because I wrote,

“Depends on etiology and patient risk stratification. Also assuming aneurysm goes to level of SMA and right renal artery origins and involves side opposite celiac. Options depending on resources of your institute: 1.Open repair with cannulation for left heart bypass and/or circulatory arrest 2.Open debranching of common hepatic, SMA, R. Renal from infrarenal inflow and then TEVAR 3.FEVAR from custom graft from manufacturer on protocol 4.Parallel grafting to CA, SMA, R. RA with TEVAR 5.Surgeon modified FEVAR 6.Open Repair We would have a multidisciplinary huddle around this patient -Vascular, Cardiac Surgery, Cardiology, Anesthesia, and ID (if needed) to help choose. Be ready to refer to a center with more resources -including prepping patient for transfer and imaging -including uploading images to the cloud for transfer with patient’s permission. More info please”

More Info Please, Indeed

The post I commented on was of a saccular aneurysm in the transdiagphragmatic segment of aorta. Ironically, only a few weeks later, I got called from hospital transfer center about a patient with a leaking aortic aneurysm, a type V thoracoabdominal aortic aneurysm as it turned out, from an outside hospital, needing urgent attention, and we accepted in transfer based on the conversation I had with the tranferring physician. And that was the problem -usually in taking these inter-hospital transfers, you have to pray that the precious CT scans come along with the patient burned correctly onto a CD-ROM. You can buy and watch a movie in 4K resolution over the internet -about 4 gigabytes, but a patient’s CT scan which is about 200 megabytes -because of various self imposed limits, overly restrictive interpretations of laws, and lack of computer skills, these life saving images get transferred on CD in 2019. That last time I purchased a CD for anything was over 15 years ago.

An Interested Party

The technical solution –to use the internet to transfer critical life saving information between hospitals – came about when our IT folks took an interest in my quarterly complaint email about using the newfangled internet for sharing files. After mulling various solutions ranging from setting up a server to using commercial cloud solutoins, we came upon the compromise of using our internal cloud with an invitation sent to the outside hospital. I would send this invitation to upload the DICOM folder of the CD-ROM to an outisde email address. It was simple and as yet untried until this night. “Would the patient agree to have his CT scan information transmitted to us electronically?” I asked the other physician. He assured me that the patient was in agreement.

It Takes Two to Tango

Of course, being able to transfer these pictures requires a willing partner on the other side, and the referring physician made it clear he did not have the technical expertise to do so. It took a bit of social engineering to think about who would have that ability. Basically, aside from myself, who spend all their time in dark rooms in the hospital in front of giant computer monitors? The radiologists! I got through to the radiologist who had interpreted the report and explained the simple thing I needed. Gratefully, he agreed, and I sent him a link to our cloud server. I explained to him, “When you receive this, clicking the link opens a browser window and then you open the CD-ROM and find the DICOM folder and drag and drop it on the browser window.” The 200-500 megabytes of data then get sent in electronic form, as it was meant to in 2019.

The Internet Saves a Life

The brutal truth is that in locking down a computer system, many hospitals make it impossible to even load an outside CD-ROM, creating many self imposed barriers to care. Thankfully, at CCAD, we were able to work together to find a secure solution. With the CTA on our servers, I was able to review the study within 15 minutes of accepting the patient, and arrange for the right team to be assembled, and confirm that we had the right material (stent grafts) for treating the patient. When the patient arrived, OR was ready to go, saving hours of time that normally would have been required if the CT scan had to be reviewed from the CD-ROM that came with the patient. Sometimes, the CD-ROM does not come, and in a critical situation, the CTA has to be repeated with some risk to the patient for complications of the contrast and radiation.

What to Do

The patient had a 8cm sphere shaped aneurysm arising in the transdiagphragmatic aorta, leaking into the right pleural cavity.

Screen Shot 2019-06-19 at 9.29.15 PM

The patient was otherwise a healthy middle aged man with risk factors of smoking and hypertension. The centerline reconstructions showed the thoracic aorta above the aneurysm to be around 20mm in diameter and same below, with the celiac axis and superior mesenteric artery in the potential seal zone of a stent graft. The only plaque seen was around the level of the renal arteries and was focal and calcified. Looking at the list I had made as a comment to the Linked-In post, I realized that I really only had one viable option.

ARTERIAL (10).jpeg

Open repair, usually the most expeditious option, was made challenging by the right hemothorax, making a left thoracotomy hazardous if the lung had to be deflated. Cardiopulmonary bypass would have to be arranged for, and that adds a metabolic hit that greatly raises the stakes. Of the endovascular solutions, the only viable option was TEVAR to exclude the rupture and debranching of the celiac axis and superior mesenteric artery. To those who would advocate for parallel grafts, there was no room in the normal 20mm diameter aorta. And branch systems for rupture are some time in the future. Also, the patient was becoming hypotensive. So the planned operation was first TEVAR to stop the bleeding, and then open surgical debranching. A hybrid repair.

plan sketch.PNG

The smallest stent graft we have is a 21mm graft, but it would not be suitable for this aorta. In practice, the normal aorta is quite elastic and will dilate much more than what is captured on a CTA. The next size we have is 28mm graft and I chose this to exclude the rupture, which was done percutaneously.

TEVAR angio.png

As seen below, the graft excluded the celiac and SMA. Late in the phase of the final aortogram (second panel) there was an endoleak that persisteed despite multiple ballooning. The timing suggested the intercostals and phrenic vessels contributed to a type II endoleak, but it was concerning.

postangio.png
Find the Endoleak

The bypasses were sent from the infrarenal aorta to the common hepatic artery and the SMA close to its origin, and the origins of the celiac axis and SMA were clipped. The bypasses were then done with a 10x8mm bifurcate Dacron graft originally for axillofemoral bypassing. It had spiral rings which I removed at the anastomosis and this resulted in a kink at the closer bypass. Usually, I loop this for iliomesenteric bypass but there was not enough distance from the infrarenal aorta. I have to add a little trick I modified from my pediatric surgery experience as a resident -a Heinecke-Mikulwicz graftoplasty:

IMG_2646.JPG

This worked to relieve the kink as evidenced on the aortogram above. After closing the laparotomy, I placed a chest tube in the right chest. The patient had a course prolonged by a classic systemic inflammatory response syndrome, with fevers, chills, and leukocytosis. He bled for a while but stopped with correction of his coagulopathy. All blood cultures were negative, but a CT scan was performed out of concern for the endoleak, and the possibility of continued bleeding.

postCTA.jpg

No endoleak was detected as the sac was fully thrombosed. There was a consolidation of the blood in the right chest, but it resolved with fibrinolytic therapy.

Discussion

This case illustrates several points I have been making on this blog.

  1. Hybrid repairs are not some kind of compromise but the full realization of a complete skill set. When students ask me how to judge a training program, one of the best metrics is how frequently are hybrid operations performed. It means either the endovascularist and open surgical operator are in complete synchrony or there are individual surgeons competent in both open and endovascular surgery. Hybrid operations, rather than being a compromise, are an optimization.
  2. Time -Laying the stent graft across the celiac and SMA origins starts a warm ischemia clock. The liver and intestines, in my reckoning, should be able to tolerate the 2 hours of work to get the bypasses working. Cardiopulmonary bypass may give you less ichemia but at the metabolic cost of the pump time. These negative factors add up, but were surmounted by the fact that early control of hemorrhage was achieved. Stopping the bleeding and restoring flow are the core functions of vascular surgery.
  3. Planning and preparation. The ability to see the CT images and prepare the teams and materiel before the patient transferred was lifesaving. This is where our IT gets credit for responding to a critical need and formulating a solution that meets internal policies, external regulations, and saves a life. It illustrates so many opportunities particularly with electronic medical records and their processes which focus more on documentation for billing. A discharge summary should be multimedia like this blog post and it should be normal and easy to generate. And finally, as clinicians, we should mind technology with as much attention as we give to the latest medical devices and techniques.
Categories
aortic dissection taaa tbad techniques TEVAR thoracabdominal aortic aneurysm type b aortic dissection

Endovascular Aortic Symposium in Bahrain

I was invited by Dr. Martin Maresch to speak on complicated type B aortic dissections. Should be an exciting day.

Categories
pseudoaneurysm stent graft infection techniques Wounds

End Stage Iatrogenic Pseudoaneurysm: Who You Gonna Call?

It’s about to blow

From Dr. Dmitirios Virvilis, formerly my trainee, now my colleague, who had this interesting case of end-stage iatrogenic pseudoaneurysm.

History

85-year-old gentleman with history of atrial fibrillation on anticoagulation, mechanical valve on Coumadin presented to our emergency department with significant hemorrhaging from the right groin (figure above).  The patient had a coronary angiogram 2 months earlier done elsewhere complicated by a pseudoaneurysm which was managed with ultrasound guided thrombin injection that was not successful.  Patient was sent to a vascular surgeon at another facility and the decision was made to intervene with the placement of a covered stent on the common femoral artery (possibly due to high patient risk?) compromising the junction of the SFA and profunda artery.  The patient developed a large hematoma following placement of the covered stent and was managed solely with antibiotics for over a month prior to presentation.

On physical examination, the patient was septic, lethargic with grossly infected groin (image above).  A CT scan with contrast was performed which showed active extravasation with stranding around the femoral vessels (below).

CT scan pseudoaneurysm virvilis

The patient was taken emergently into the operating room.  Due to the extent of the infection under the inguinal ligament I obtained proximal control by performing a retroperitoneal flank incision.  The iliac vessels were controlled and then I proceed with exploration of the hematoma.  The junction of the superficial femoral artery and the profunda artery was separated and the common femoral artery was liquefied. There was only a very thin posterior layer of the common femoral artery and the cover stent was floating in the  hematoma.  The wound was thoroughly debrided. The distal external iliac artery was transected and the stent was removed. The junction of the superficial femoral artery and profunda artery were separated. A Rifampin soaked graft was used (picture below), which was an 8mm gelatin impregnated Dacron graft soaked in Rifampin (600mg in 200mL of saline) for 20 minutes.

insitu graft virvilis

The graft was anastomosed to the common iliac artery to fully exclude the external iliac artery which was debrided and ligated. The profunda artery was reimplanted on the side of the graft in an end-to-side fashion.  After the wound was thoroughly irrigated and the graft was covered . The muscle flap was created in the usual fashion with lateral mobilization preserving the medial vascular pedicle.  The wound was partially approximated and the top of the wound was left open for an application of wound VAC (below). The fact that I am practicing in a  remote area has made me to be more efficient and incorporate in my practice many procedures picked up through training that fall under general surgery, plastic surgery, and advanced vascular surgery.

wound virvilis flap.png

Patient remained hemodynamically stable and recovered in the ICU for 48 hours. After hospital course of approximately 5 days was finally discharged to rehabilitation center.  Patient was seen 1 month and 2 months after the first operation and has had completely healed incision (below).  There is a strong femoral pulse on the right groin with multiphasic pedal signals.  Patient has completed 8 weeks of IV antibiotics.  I am planning to perform a CT angio with runoff in the next few months in order to evaluate my distal anastomosis because I am concerned about the Pseudomonas that grew from the OR cultures.

healed groin virvilis.png

From technical standpoint there is 2 things that I would like to address:

#1: The textbook answer would  be to perform a bypass with a native conduit with deep femoral vein or great saphenous vein, but this is difficult to perform efficiently solo.  I do not have CryoVein on the shelf and the cost of such a conduit is prohibitive in my institution.  And extra-anatomic bypass also on the lateral approach, an obturator bypass, adds time and complexity especially with the separation of profunda and superficialis.

#2 Next time I will have to perform a bypass like that I will probably perform the bypass first to the profunda artery and then reimplant the SFA which is more mobile.

Discussion by W. Michael Park, MD

I have to congratulate Dr. Virvilis on this nice outcome. I agree on remaining vigilant for late re-emergence of infection, but it is very unlikely to occur as time passes without signs and symptoms. I have three things to add. First is that Rifampin soaked graft is effective in revascularizing within a decontaminated field while sewing to uninfected artery. Taking the graft to the common iliac bifurcation which was exposed to gain proximal control was wise as anastomoses to the external iliac under the inguinal ligament are challenging and there was an unknown degree of infection here. Second is the sartorius muscle flap must be in the armamentarium of every vascular surgeon and is an easy jumpoff point to learning gracilis and rectus femoris flaps as well. The lateral mobilization and medial rotation is done preserving the medial arteries that feed the graft -dividing too many of these to mobilize the flap kills the flap. The flap delivers the immune cells and vascularity to clear the remnants of infection and forms a better granulation source bed than debrided, infected wound.

Finally, Dr. Virvilis did reach out to me from around the planet (I work in Abu Dhabi, he in Mississippi) for a run through of his plan. I cannot tell you how valuable this is to be able to bounce ideas off of someone you trust. When I graduated from my fellowship, Tom Bower put his hand on my shoulder and said, “Do not hesitate to call me if you have a difficult situation.” I have since grown a long short-list of mentors, friends, and partners on speed dial. It taps me into cumulative millennia of surgeon-years of experience. With social media and increasing acceptance of its use to share ideas, there is absolutely no reason to work in isolation.