A basic recipe for treating complicated aortic dissection
A basic recipe for treating complicated aortic dissection
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.
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.
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.
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.
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.
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:
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.
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.
This case illustrates several points I have been making on this blog.
Innovating Our Way Out of Not Having Enough Vascular Surgeons
This year’s SVS meeting featured a sobering assessment about the vascular manpower deficit affecting North America at the E. Stanley Crawford Critical Issues Forum, moderated by Dr. Michel Makaroun, MD, president-elect of the SVS. 35-45% of practicing vascular surgeons plan on retiring in the next decade by conservative estimates. We are not attracting enough candidates for the training programs. The solutions, including decreasing the length of training, public relations campaigns, and incentivizing retention have had mixed results, but we have yet to see a sustainable rise in vascular surgeon numbers.
Burnout driven by lack of work-life balance, the advent of electronic medical records optimized for billing, the passing of the private practice era, and the constant need to adapt to new techniques, create a persistent downdraft on staffing. So as some hospital face the reality of having to contract services, little attention is given to delivering best care with the staffing that we have. Changing how we practice is the only viable solution.
There are an estimated 3000 active vascular surgeons in the US. Imagine if all the cheese needs of this country could only be met by 3000 artisanal cheesemakers who make cheeses one at a time and want to live in places with international airports, BMW dealerships, and major league sports teams, and must have 3-4 partners to share cheese call. If you are a rural hospital in dire need of vascular surgery services and your one vascular surgeon is retiring, you are probably SOL.
When I was training, vascular surgery was oft touted as a primary care specialty. And that is how many of us still practice, managing risk factors, monitoring mild disease, as well as planning and performing interventions and operations. As much as I enjoy that kind of interaction, the half hour to an hour visit for a head to toe cardiovascular survey and discussion, educating patients and families about pipes and pumps, is incredibly inefficient. A healthcare system, a hospital, facing a staffing shortfall, has to do everything possible keep that vascular surgeon in the OR during work hours.
What is the core function of a vascular surgeon? Making good decisions and executing plans well. Decisions require data. What is this data? We laud the history and physical examination, but this is a throwback to another era. If you look at the diagnosis of myocardial infarction, it is not standard practice for a cardiologist to come and get a history, examine the patient, and declare that the patient is having a heart attack based solely on history and physical examination. It is a triage nurse in the ED who draws labs and orders an EKG which is read by a machine. These data points will tell you if heart muscle is being damaged. A process is started which triggers a team to come and take care of this patient. The hospitals focused on this actually drill their cath lab teams like pit crews. A stopwatch starts with the goal of revascularization under an hour.
Not so with peripheral vascular disease. The ischemic foot might have only a few hours depending on its presentation before it is irretrievably lost, but no matter -they sit in the ED until a vascular surgeon comes to speak to the patient and family, examine them, and then order tests, admission, consults, and operating room -typically all by themselves. Getting these patients into the operating room is in many places hampered by the lack of dedicated OR staffing, radiology techs, anesthesiologists, space, equipment, and critical care capacity. During work hours, there are scheduled cases that have to be delayed or canceled for another time, which takes time to do. After hours, the patient may have too many comorbidities to handle safely with the available staff. The vascular surgeon may have to bargain and cajole, to align several factions whose attention is demanded by many equally important concerns. If you decide to hold a lavish dinner party of twenty important guests -reserving space, calling caterers, inviting guests, arranging transportation – on short notice, you might pull it off once, but if you do this regularly, you are a masochist of the first order.
In the heart attack model, the history and physical examination is relegated to a series of yes/no or how long questions, and positive responses trigger a series of coordinated actions of a system -a reflex. In the leg attack model, there is no such system. I have to blame the vascular surgeons for preserving the current model. Vascular surgeons are organized as a guild. Guilds are protective of their monopolies on skills and markets and fiercely resist change. Most vascular surgeons are terrified by loss of control, and cling to the notion of being misunderstood and unappreciated saviors. We can do better.
The area that needs streamlining is at the point of referral. The majority of time of a vascular surgeon is spent working up normal blood vessels, varicose and spider veins, leg edema and pain, and mild and moderate arterial atherosclerosis. This work initially does not require a vascular surgeon but rather a focused set of policies and initial diagnostic studies that can be administered or ordered by any caregiver. Reducing the need for vascular surgeons at this point in vascular care will go a long way in extending the vascular work force at hand.
Point of Care Blood Flow Evaluation
Finding and declaring blood vessels to be normal is challenging and too often time consuming. Streamlining this will go a long way in freeing vascular surgeons to take care of disease.
The average caregiver is an inconsistent pulse taker. The palpable pulses are not always easy to find. Asking over the phone or as policy for someone to examine pedal pulses -the posterior tibial artery and dorsalis pedis artery pulses, is challenging. A positive is just as likely to be true or false as a negative. No cardiologist would ask a similarly detailed and technical question about an MI. In fact, they can’t ask, “Is there a pulse in the LAD?” Cardiologists make do with tests easy to obtain and interpret with certainty -the plasma troponin level and the EKG. The EKG is read by an algorithm so established and so tested, that it should stand as an example of early machine intelligence taking over a human job -but I digress.
What is our EKG? It is not the ABI -the ankle brachial index, because it is terrible at identifying disease, and is difficult to obtain reliably without practice. The closest thing to an EKG we have in terms of simplicity and accuracy is the pulse volume recording, the PVR (figure below). A FloLab machine, the machine used to obtain PVRs, will basically run itself once the cuffs are correctly applied on the leg, and the tracings are very easy to interpret. Unlike an EKG, there are no electrodes whose locations you must memorize. If the closest vascular surgeon is an hour away by ambulance, the transfer of a patient with flat waveforms and ischemic foot does not require a consultation on site. The patient would go to the vascular surgeon with no time wasted and no kidneys injured by CTA’s that too often fail to travel with the patient. Unlike an EKG which can be performed by many caregivers, a PVR requires both the equipment and a vascular technologist. A vascular technologist is not available 24-7 in most hospitals, and FloLab machines purchased for vascular labs are not meant to be dragged around the hospital.
So let’s think out of the box about another box in every triage nurse’s cell, every ER and ICU bed, and on every hospital nursing floor. These are pulse oximeters with a digital tracing, and bonus points, some come with strip printers! Placing a pulse oximeter probe on the second toe and comparing to an erstwhile normal wave signal such as on an index finger can provide qualitative information about normality and disease. Normal waveforms and abnormal ones can be easily discerned. A flat line is another obvious finding when in comparison, a finger or an ear on the same patient has normal signals.
How much better would a vascular surgeon feel about a transfer call that has this information, “digital waveforms are flat in this patient with rest pain and a bruised toe.” How much better would a vascular surgeon feel about a call about a patient with “digital wave forms are normal in this patient with toe pain and a bruised toe. We got an x-ray and there was a fracture.” The communication can be quite detailed and refined. For example: “The patient had no pulses, we think. Digital wave forms were dampened but pulsatile in a patient with a bruised toe, we’ll send to vascular clinic in the morning.”
These data suggests pulse oximetry signal is equal to and somewhat better than ABI. Why is this important? Cost. This information is better than asking unsure people, “Is there a pulse?” A vascular technologist need not be on call 24/7. Extra FloLabs for ED, ICU, and floors need not be purchased. The pulse oximeter with waveform tracing is nearly ubiquitous wherever patient’s oxygenation needs to be assessed in most hospitals. While not perfect, it has great potential for serving as vascular surgery’s EKG machine for critical limb ischemia. Policies and algorithms can be built out in collaboration with Emergency Departments and nursing departments that can effectively determine if blood flow is normal or abnormal at point of care. Effective emergency responses to critical limb ischemia can be authored triggered by abnormal findings. Acute limb ischemia protocols based on time sensitive responses can be initiated. All of these can flow from referring entities being able to determine objectively normal or abnormal blood flow.
The vascular clinic is a sorting process where patients are determined to be normal or have mild, moderate, or severe disease. The vast majority of the time spent in clinic can be spent in triage by trained nurses and testing by technologists. Clear pathways and guidelines can dictate the ordering of vascular laboratory tests obviating the need for vascular consultation at this stage. Patients with normal blood vessels and vascular function are sent back to their physicians with the normal report. Patients with mild disease and moderate disease are sent to a physician with specialization in cardiovascular medicine for management of risk factors and periodic surveillance. At any point in the process, a vascular surgeon can be called to provide guidance and direct patients to different tests and consultations. The patients needing operations, based on correct indications and imaging are sent to a focused clinic where the surgeon and interventional team can review films, determine the urgency of indications balanced against risk, and plan and schedule procedures. Currently, vascular surgeons do all of this by themselves, as well as make hospital rounds, perform procedures, and interpret vascular laboratory studies, seeing one patient at a time.
In introductory computer sciences courses, search algorithms are taught to be brute force if you look at one item at a time for the thing you want, and to be efficient if you have presorted those items because every time you look, you can exclude part of the data set, ever shrinking the pool in which you search, making the search shorter and faster
The shortfalls in vascular surgeon numbers have as much to do with this dependence on the star chef cooking up one meal at a time, rather than a team working off recipes, with the chef directing the flow and occasionally jumping by the fire to make the most difficult of dishes. The first restaurant can seat three parties. The latter, easily ten times the number. Everyone gets fed.
Only asking how many vascular surgeons you need misses the big picture because there are many equally important questions. How many vascular technologists do you need? An accredited laboratory provides the critical diagnostics upon which decisions are made, and the surgeon should oversee but not be directly involved in the initial screening. Nurses trained to triage and order vascular laboratory tests and even perform the simpler ones is the second need. Third, is the cardiovascular medicine physician who manages those patients discovered to have mild to moderate disease, and depending on symptoms, refers severely symptomatic moderate disease and severe disease to a scheduling clinic. The scheduling clinic is composed of both interventionalists and vascular surgeons who plan interventions and operations.
Surgeons must be in the operating room to be effective. A well thought out and organized system, with interlocking teams, and well disseminated basic knowledge and awareness of vascular diseases reduces the need for a vascular surgeon to be present all the time in many places and ultimately increases the effectiveness of the vascular surgeons that are available by keeping them in the operating room. The system needs to be set up by the surgeon to allow clinic to be a setting mostly for consenting the patient for an operation or a discussion of treatment options.
Finally, vascular surgeons must be aligned with all the resources of the hospital including the considerable numbers of interventional cardiologists and radiologists, neurologists, and nephrologists. There is no reason someone should wait a month to get on the OR list for an iliac angioplasty and stent if an equally skilled and privileged cardiologist or radiologist has an opening the next day. The surgeon’s special talent should be open surgery and hybrid surgery -that which mixes open surgery and intervention in optimal measures which is not possible from a purely percutaneous approach. The key is frequent and easy communication between specialities and trust built by being in one shared cardiovascular institute.
There is a critical need of good operators. The acuity of disease and their solutions demand the continued presence and availability of open surgery. The fact is, many solutions are optimal in a hybrid fashion and for peripheral vascular disease, these options can only be offered via a vascular surgeon trained in both open surgery and peripheral interventions, or in a combined effort of open surgeon and interventionalist. And many disease categories can only be managed by open surgery.
The reality is that silos, economics, and practice patterns prevent this kind of combined effort. Market forces have pushed the training of vascular surgeons forcefully into the interventional realm at the cost of open surgical training. Some of the geographic maldisdribution of vascular surgeons has to do with younger vascular surgeons flocking to established practices where there are senior surgeons more comfortable in opening a belly or chest (or both). The trap they and hospital systems fall into is then allowing these new recruits to become the interventional specialist of that group, relegating the aging open surgeon to a narrow role, and then finding that the hospital has a problem when that surgeon announces retirement at 60. Every year, millennia of surgical experience retires to beaches and golf courses. The hospital systems should recognize this brain drain as a crisis and create work arounds that keep these skills going. The other opportunity lost is close coordination with interventional cardiologists, radiologists, and nephrologists who in many cases compete with vascular surgeons for the same patients but treat the patients based on their training and skill sets to the exclusion of potentially better operations offered by surgeons. This disjointed care creates both suboptimal outcomes for patients and high costs for hospital systems.
Commerce should never dictate the fate of a patient. A particular point is where competencies and privileging overlap, and guidelines recommend intervention over surgery as in the case of a TASC A or B iliac artery lesion. A patient should not be kept waiting weeks for a spot on a busy surgeon’s OR schedule when an open interventional cardiologist or radiologist slot is available for a iliac stent the next day. It should be a matter of practice that these cases are discussed and distributed, optimally in a shared indication clinic or rounds. Patients bumped off of a surgeon’s elective schedules for emergencies who could be cared for by an interventional partner without an added delay should be given that option. This kind of change requires a commitment to continual reorganization and optimization into a vascular institute.
The perfect vascular surgeon is a unicorn -well skilled, and experienced in open vascular surgery, but also versatile, innovative, and skillful in wielding a wire. I can name just a handful of unicorns. An apt analogy from the book Moneyball is the signing of superstars in baseball on the free agent market. The upshot of that book is that you can arbitrage for the valued metrics through signing several utility players with an aptitude for one thing or another which in sum equals or exceeds that superstar and get the final result -wins, in the same proportions as overspending on a superstar. Rather than searching for that unicorn, it is more important to set up the right system. Screening, testing, and management of mild vascular disease by a nurses and cardiovascular medicine physicians, while directing operations and interventions to vascular surgeons, cardiologists, and interventional radiologists should be the next step in the evolution of vascular care systems. There will never be enough vascular surgeons in the current system. The critical and rare competency is open vascular surgical skill. A surgeon who performs only interventions is not an “advanced minimally invasive practitioner” but rather someone equally privileged as an interventional cardiologist or radiologist, and therefore easily replaceable by an interventional cardiologist or radiologist specializing in peripheral vascular disease. A surgeon skilled in open vascular surgery is becoming rarer every year, but they are still out there, looking at brochures of real estate in sunny places. A team consisting of a cardiovascular medicine physician, many vascular technologists, nurses specializing in vascular diseases, several interventionalists, and a vascular surgeon skilled in open vascular surgery working as a single unit, is far more easy to assemble than finding and recruiting a herd of unicorns.
I recently had to remove a stent graft for infection and got to thinking about how the number of people who could comfortably and confidently manage that has thinned out in the world through the unintended consequence of the medical device market place. In every surgical specialty over the past twenty years, many open procedures were replaced with a minimally invasive option which generally involved adoption of new technology and large costs to the hospital. These newer procedures were touted as easier on the patient while being easier to perform for the average physician than the open procedure that they were replacing. That was the other selling point -that one could do several of these operations in the time it took one open procedure. In most cases, they were at best almost as good as the open procedure but at higher cost.
In the marketplace, minimally invasive always wins. In many specialties it became untenable to practice without marketing these “advanced minimally invasive” skills. Hence, the wide adoption of robotics in urology outside major academic centers -during those years of rapid adoption the surgeons would get flown to a course, work on an animal model, then for their first case a proctor would be flown out and voila -a minimally invasive specialist is born. The problem comes when learning these skills displaces the learning of traditional open surgical skills. In general surgery, it is not uncommon to hear of residents graduating without having ever having done an open cholecystectomy. It is also the case that many vascular trainees graduate with but a few if any open aortic cases. What happens when minimally invasive options run out? Who will do my carotid endarterectomy or open AAA repair?
The first case is an elderly man with an enlarging AAA sac despite having had EVAR about seven years prior. No endoleak was demonstrated but the proximal seal was short on CT. Also, it was a first generation graft which is prone to “peek a boo” endoleaks from graft junctions and stent anchoring sutures. On that last point, I use the analogy of a patio umbrella -after seven seasons, they can leak where cloth is sewn to the metal struts. It is very hard to demonstrate leak of this kind on CTA or duplex ultrasound because they are small. The patient had his EVAR because he was considered high risk for open repair at the time of his operation -moderate COPD, mild cardiac dysfunction. His sac had enlarged to over 6cm in a short time, and therefore open conversion was undertaken. No clinical signs of infection were present. A retroperitoneal approach was undertaken. After clamps were positioned, the sac was opened.
The picture does not show it, but a leak from the posterior proximal seal zone was seen with clamp off. The clamp was reapplied and the graft transected flush to the aortic neck. A bifurcated graft was sewn to this neck incorporating the main body stent graft and aortic neck in a generous running suture. The left iliac limb came out well and the new graft limb sewn to the iliac orifice, the right iliac limb was harder to clamp and therefore I clamped the stent graft and sewed the open graft to the stent graft.
The patient recovered well and went home within the week. He was relieved at no longer needing annual CT scans.
Who needs annual CT scans? Patients with metastatic cancer in remission.
The second patient was an older man referred for enlarging AAA sac without visible endoleak. The aneurysm had grown over 7cm and was causing discomfort with bending forward. He too had been deemed high risk for open repair prior to his EVAR. If he had had an early generation Excluder graft, the possibility of ultrafiltration would be more likely and relining the graft would be reasonable (link). This was again a cloth and metal stent graft which can develop intermittent bleeding from graft to stent sutures, and I don’t think relining will help.
The patient was taken for open repair (above), and on opening the AAA sac, bleeding could be seen coming from the flow divider. It stopped with pressure, but I replaced the graft in a limited fashion from the neck to the iliac limbs as in the first case. This patient did very well and was discharged home under a week.
The third patient was another fellow referred from outside who had an EVAR for a very short and angulated neck, and a secondary procedure with an aortic extension in an attempt to seal the leak had been done. This failed to seal the type Ia leak. This patient too was deemed too high risk for open surgery of what was basically a juxtarenal AAA with very tortuous anatomy.
The patient was taken for open repair, and the stent grafts slid out easily (below).
A tube graft was sewn to the short aortic neck and distally anastomosed to the main body of the stent graft -with pledgets because of the thin PTFE graft material in this particular graft. This patient did well and went home within a week.
All three cases are patients who were deemed originally too high risk for open repair, who underwent EVAR, then underwent explantation of their failing stent graft. Only one involved a patient whose graft was placed off the IFU (short angled neck), but the rationale was that he was too high risk.
What is high risk? In non-ruptured, non-infected explantation of failing stent graft, the mortality is 3% (ref 2) from an earlier series from Cleveland Clinic. With stent graft infection, the 30-day mortality of surgical management from a multi-institutional series was 11% (ref 3) when there was no rupture. From a Mayo Clinic series, stent graft resection for infection came with a 4% 30-day mortality (ref 4). These were nominally all high risk patients at the time of the original EVAR.
Real world risk is a range at the intersection of patient risk and the expertise of the operating room, critical care, and hospital floor teams. The constant factor is the surgeon.
Endografts for AAA disease (EVAR, endovascular aortic aneurysm repair), makes simple work of a traditionally complex operation, the open aortic aneurysm repair. The issue has been the cost and risks of long term followup as well as endograft failure and aneurysm rupture. The Instructions For Use on these devices recommend a preop, a followup 1 month, 6 month, and 12 month CTA (with contrast) and annual followup with CTA for life. These devices were meant to treat high risk patients but high risk patients with limited life spans do not benefit from EVAR (ref 1, EVAR-2 Trial). These have lead the NHS in the UK to propose that EVAR has no role in the elective repair of abdominal aortic aneurysms in their draft proposal for the NICE guidelines for management of AAA (link). While this is a critical discussion, it is a discussion that is coming at least ten years too late. A generation of surgeons have been brought up with endovascular repair, and to suddenly announce that they must become DeBakey’s, Wiley’s, Imperato’s, and Rutherford’s is wishful thinking at best or wilful rationing of services at worst.
In 2006, Guidant pacemakers were recalled because of a 1000 cases of possible capacitor failure out of 28,000 implants for a failure rate of 3.7% -there were 2 deaths for a fatality rate of 0.00007%. EVAR-1 Trial’s 8 year result (ref 5) reported 16 aneurysm related deaths out of 339 patients (1.3%) in the EVAR group compared to 3 aneurysm related deaths out of 333 patients (0.2%) in the OPEN group.
Academic medical centers, behemoths though they are, serve a critical function in that they are critical repositories of human capital. The elders of vascular surgery, that first and second generation of surgeons who trained and received board certification, are still there and serving a vital role in preserving open aortic surgery. My generation -the ones who trained in both open and endovascular, are still here, but market forces have pushed many of my colleagues into becoming pure endovascularists. The younger generation recognizes this and last year, I sat in on an open surgical technique course at the ESVS meeting in Lyons organized by Dr. Fernando Gallardo and colleagues. It was fully attended and wonderfully proctored by master surgeons. This is of critical importance and not a trivial matter. As in the 2000’s when endovascular training was offered as a postgraduate fellowship in centers of excellence, there is no doubt in my mind that today, exovascular fellowships need to be considered and planned and that current training must reinvigorate and reincorporate their open surgical components.
During our daily morning huddles, peopled by cardiologists and cardiac surgeons, one thing impresses me more than anything else. The assembled interventional cardiologists, world class and renown, they who can place a stent in any part of the body, will defer to the unassailable superiority of the LIMA to LAD bypass over any existing intervention. I am always a little sad that the analog for this, the vein bypass in the leg does not get the same love. The open surgical bypass of the leg is the great straw man at international symposia. It is fast becoming a diminishing and curious habit of a fading generation.
The acknowledged superior hemodynamics and patency of the bypass is diminished in the literature by pooling patency loss with other factors such as amputation, heart attacks, and death. Some vascular surgeons dogmatically cling to habits learned in training that favor complications, making themselves their own worst enemies both in the literature and in the marketplace. These bad habits involve long incision length, closure techniques that do not anticipate edema, and wound orientation that makes failure more likely.
Operations require far more support and resources to succeed than do interventions that soon go home. Brilliant operations alone will not heal the patient. It is pathways and postoperative care infrastructure and staff that prevent these secondary complications -the very complications that keep the leg vein bypass from being as respected, if not loved, as the LIMA to LAD.
The postoperative care of these patients devolves to management of leg edema. No medical or nursing school adequately teaches the basic science nor management of edema, which is the most common vascular condition
The incisions are too long in the classic vein bypass. When you create and then close an incision, the inflammation drives the accumulation of fluid in the extracellular space – creating edema. This postoperative edema, poorly managed, results in complications that leave the patient hobbled with time lost to healing wound complications, pain, and excess limb weight. Additionally, vein bypasses usually involve groin exposure and the delicate lymphatics that coalesce there are perturbed or destroyed during exposure. Postop, this damage and the inflammation rapidly overcomes the capacity of a lymphatic system. The traditional vein harvest also involves cutting through deep layers of fat. The fat is typically closed by broad sutures that create areas of fat necrosis -potential fodder for bacteria. The best ways the complications of long and deep incisions is to avoid them altogether. The calculus of the operative moment – “I must see the vein,” must include the vision of a patient losing months to wound therapies to heal a gaping, necrotic, infected wound. I recommend skip incisions or adopting in-situ bypass technique with endovascular management of fistulae. Or corral your cardiac PA to harvest the vein segment in the thigh after mobilizing the vein in the leg with the endoscope.
The incisions are often closed with Nylon sutures and skin clips which can become potential foci of infection. With edema, they create zones of ischemia around them, killing skin and creating entry points for skin flora as the skin expands under an unyielding clip or suture. Placed under a pannus, these sutures or clips fester in an anaerobic environment. Closure should adhere to anatomy. The body relies on connective tissue planes to keep itself together. In the groin, these are Scarpa’s layer and the dermis. They should be closed with absorbable monofilament in a buried interrupted fashion at the dermis with a final running subcuticular layer of 4-0 absorbable monofilament. Steristrips or glue at the skin finishes the job. If you use sutures, particularly at the distal anastomotic site, take care to realize that you have about 12 hours before the skin dies in the best of circumstances, and less with microangiopathy of diabetes and ESRD. Squeezing out the edema before closure with a sterile Esmarch or short counterincisions or even a large one to allow for tension free closure over an anastomosis will prevent wound complications over your graft.
The classic longitudinal groin incisions that cut across the inguinal crease divides a tension point -that crease is like a cord that supports the pannus that is slung over it and when divided and then closed with a stitch, that stitch then bears the weight of that pannus every time the patient sits up or stands. If you are observant, wound necrosis typically starts at the groin crease under a surgical clip or suture. Incisions in the groin should be obqlique and parallel to this crease, or if you can, even inside this crease. When these wounds are closed, the natural lines of tension are in line with the incision rather than orthogonal to it. The natural forces keep the wound shut.
This is only the first step. The next is keeping the wound clean and dry for at least 5 days. At the Mayo Clinic, where I trained, the nurses up on 5 Mary Brigh were trained to blow dry the groin wounds every few hours on cool setting and redressing the wound with dry gauze. You can get something close to it by ensuring the wounds painted with betadine, allowed to air dry, and dressed with dry gauze. If there is a constant leak of fluid, you have a serious problem as there is too much edema in the leg, or the wound isn’t closed, or there is a lymph leak. It needs to be actively dried out or you get a wet, macerated, infected wound like a grenade went off in the groin.
They don’t teach compression wrap techniques in medical or nursing school
The simplest thing to avoid lymph leaks is to not make them. Cutting near lymph nodes is hazardous, and once below Scarpa’s you have to orient your dissection directly over the femoral artery. Stray horizontally and you will undoubtedly cut one of the 4 to 10 invisible lymph channels.
They are invisible but detectable -after you break them, you will see a constant wetness in the wound. Think about injecting a cc or two of Lymphazurin (Isosulfan Blue, for those not allergic to Sulfa) into the intertriginous space on the same foot and you will see the lymph channel in bright blue, or stare carefully at the likely spots for a lymph leak and clip it, burn it, Ligasure or Harmonic scalpel it.
So how did we get to a rather dry discussion about edema? Wound complications are tremendously debilitating and offset any benefit from vein bypass operations. These long incisions become terrible big wounds if not prevented. It takes the concerted effort of a team and particularly nursing in actively managing edema. And at the end, the patient too must be included in this discussion. For the vein bypass of the leg to get the same respect and love as the LIMA to LAD bypass, surgical wound complications must become never events.
The patient is an 80 year old woman with lung cancer who was getting a port placed at her home institution. It was to be a left subclavian venous port, but when access was not gained, a left internal jugular venous port was attempted, but after the intitial stick and sheath placement, pulsatile bleeding was recognized and the sheath removed. Hemostasis was achieved with clips and the wound closed and a right internal jugular venous port was placed. The postprocedural CXR shown above showed tracheal deviation and numerous clips from the initial port placement attempt, and a CT scan with contrast (unavailable) showed a carotid pseudoaneurysm of 3cm projecting posteriorly behind the pharynx/esophagus. She was kept intubated and sedated, and transferred for management.
On examination, her vital signs were stable. She had 2cm of tracheal deviation and swelling was apparent at the base of the neck. While my trainees may be better versed at this than I at the particulars of this, my old general surgery trauma training kicked in, as she had a Zone I neck carotid injury, which in my experience is highly morbid despite how stable the patient was. Point again to trainees, this is no different from someone having stabbed this patient with a knife at the base of the neck. My options were:
Open repair is the approach of choice for zone 2 injuries because aerodigestive tract injuries can also be addressed and the exposure is straightforward. For Zone 1 injury, the exposure is potentially possible from a neck exposure, but in my experience, jumping into these without prepping for a sternotomy puts you into a situation without a plan B. The exposure of the carotid artery at this level becomes challenging with hemorrage from the artery once the compression from the hematoma or pseudoaneurysm is released. A sternotomy in this elderly woman, while not optimal, may be necessary if open control is required, but the best plan is to avoid this.
This should be a straightforward repair from an endovascular approach, even with the larger sheath required for the covered stents. A purely endovascular approach is problematic for two reasons. One, cerebral protection devices are built for bare carotid stents and not peripheral stent grafts, but this is not prohibitive -it should be fine. Without a planned drainage, the hematoma would be left behind which could cause prolonged intubation and problems with swallowing -both an issue for an elderly patient battling lung cancer. Endovascular access could provide proximal control for an open attempt from above, but instrumenting from the arch in an 80 year old has a known 0.5-1% stroke rate.
A hybrid open approach with exposure at the carotid bifurcation offers several advantages. With control of the internal carotid artery, cerebral protection is assured while the carotid artery is manipulated. At the end of the procedure, the internal carotid can be backbled through the access site with the common carotid artery clamped. The hematoma could be avoided until the stent graft is deployed. An unprotected maniplation in the arch can be avoided. Once the stent graft is deployed, drainage of the hematoma can be performed.
This required setting up a table off the patient’s left that allowed the wire to lie flat to be manipulated by my right hand. The carotid bifurcation was accessed through a small oblique skin line incision and the common, internal, and external carotid arteries, which were relatively atherosclerosis free, were controlled with vessel loops. The patient was heparinized. The internal carotid was occluded with the loop, and the common carotid below the bifurcation was accessed and an 8F sheath with a marker tip inserted over wire. Arteriography showed the injury and pseudoaneurysm.
The location of the injury based on CT and on this angio would have baited a younger me into directly exposing it, but experience has taught me that which occasionally you can get away with it, the downsides -massive hemorrhage, stroke, need for sternotomy, just aren’t worth it. The sheath was brought across the injury and a Viabahn stent graft was deployed across the injury.
The hemorrhage was controlled and the hematoma was then exposed and drained -the cavity was relatively small and accepted the tip of a Yankauer suction easily. A Jackson-Pratt drain was placed. The access site was repaired after flushing and retrograde venting as described.
She recovered rapidly after extubation postop. She was able to breath and swallow without difficulty and had suffered neither stroke nor cranial nerve injury. The drain was removed on postop day 2.
The patient recently returned for a 6 month followup. Duplex showed wide patency of her stent.
More gratifyingly, her port was removed as her cancer was controlled with an oral regimen.
Let me start with my bias that all penetrating trauma should be approached in a hybrid endovascular OR. It is a natural setting for trauma and this case illustrates that. In a hybrid operating room, central aortic and venous injuries can be controlled endovascularly while open repair, including salvage packing, can be done. Excess morbidity of central vascular exposures can be avoided. Temporary IVC filters can be placed if indicated (becoming rarer and rarer). Cardiopulmonary bypass can be started.
In this patient, hybrid therapy brought the best of both techniques and avoided many of the pitfalls of the purely open or endovascular approach. For stable zone I penetrating injuries of the neck, it is clear that this is a reasonable approach.
Max Wohlauer, a recent graduate, is now Assistant Professor of Surgery at the Medical College of Wisconsin in the Division of Vascular Surgery. He sent along a case which is published with his patient’s and department’s permission.
The patient is an 80 year old man with diabetes mellitus, CHF, and pulmonary fibrosis, who presents with right foot toe ulcers. He had an inflow procedure earlier in the year, but it failed to heal the ulcers. An attempt at crossing a CTO of the SFA/POP failed. Angiogram (above), showed a distal anterior tibial artery target.
Preop ABI, TBI’s, toe waveforms, and pulse Dopplers are shown. are as shown.
All point to likely limb loss. The TBI is 0 and the ABI is incompressible. Max planned for bypass. The saphenous vein was mapped and shown to be adequate.
The operation went well. Completion angiography was performed showing a patent bypass and distal anastomosis with good runoff.
A followup duplex showed patency of the graft.
Postop ABI’s showed excellent results:
Commentary from Park
Bypasses work and are possible even in high risk individuals with good anesthesia and postoperative care. Because open vascular surgical skills are not well distributed while endovascular skills are more widely distributed, there is bias both in the popular mind and even among some catheter based specialists that bypass surgery is a terrible, no good thing. The fact is that a well planned bypass is usually both effective and durable even in high risk patients, but clearly it is not the only option.
Ongoing developments in endovascular technology bring greater possibilities for revasularizing patients. As someone who does both interventions and operations, I have seen spectacular success (and occasional failure) with both approaches, and I admit to having biases. It is human nature to be biased, but it is because of my biases, I support further ongoing study, as the mistake would be to establish monumental truths without supporting evidence. There is an ongoing randomized prospective trial (BEST-CLI) that aims to answer important questions about what approach brings about the best results in critical limb ischemia. It will bring evidence and hopefully, clarity, to this important disease.*
Finally, I am very proud to have participated in Dr. Wohlauer’s training, and look forward to seeing his evidence, experience, and even biases, presented at future meetings.
*CCF is a BEST-CLI study site.