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.

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.

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.

 

Complicated Aortic Dissection Talk

A basic recipe for treating complicated aortic dissection

#aorticsurgery #tevar

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.

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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.

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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:

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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.

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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.

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.

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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.

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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.