A lot of people can put in a stent graft, unfortunately only a few can take them out.

 

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Drs. Roy Miler and Xiao Yi Teng performing anastomosis on open coversion of an aortic stent graft, now graduated and in practice. A significant part of their open aortic experience is in addressing failing stent grafts.

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.

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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.

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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.

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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).

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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.

References

  1. Lancet 2005;365:2187–92.
  2. J Vasc Surg. 2009 Mar;49(3):589-95.
  3. J Vasc Surg. 2016 Feb;63(2):332-40.
  4. J Vasc Surg. 2013 Aug;58(2):371-9.
  5. Lancet 2005;365:2179–86.

Last Slides Should Pack a Punch

When I lecture to interventionalists (cough, cardiologists), I often end with some variation on the following:

1. The common femoral artery is the left main of the leg, so why would you ever leave a stent across the LCX?

2. Claudication is like stable angina, so is it okay to intervene on a long LAD CTO for stable angina?

3. Gangrene and ulceration are like STEMI and Non-STEMI, only you can’t take the dressing down on an infarcted heart three times a day and wash away the debris.

4. If a LIMA to LAD isn’t a failure and lasts many years beyond the best stents, how is a femoral to tibial bypass a failure?

5. Why is that [insert technology] is a failure in the coronary circulation but the latest and greatest thing in the peripheral circulation?

6. Reversible ischemia is well demonstrated in the foot by lifting it off the bed and watching the color change. It’s too bad for vascular surgeons we can’t build a giant white box around this test and have have the hospital build a center around it.

7. The ABI is a great test of cardiac risk, not so much for peripheral vascular disease.

8. Hybrid revascularization works for the legs in the same way it works for the heart -you maximize the hand that you are dealt.

9. The nitinol throne is not won without some cost.

10. One day, in the far future, someone will dig up an ancient human that is more nitinol, stainless, steel, and chromium, than bone, from the mitral valve out to the fingers and toes.

In Medicine, We Can All Be Real-World Innovators

By W. Michael Park, MD

 

Innovation has become a virtue in the current culture. There is an  evangelical fervor around it. What are TED Talks but tent revivals for nerds? What is the new Apple campus but a cathedral born out of the values of our time? Yet in elevating the more famous innovators and inventions to lofty heights, we lose sight of its very practical and useful daily application. Rather than treat it like inspiration from the heavens, we should approach it as a trait that we all share in.

 

To make it work for you, you have to think of it as a muscle, and put your reps in. Here are a few “training” tips:

 

  1. If someone (maybe you) complains about something that feels like drudgery, fix it.
  2. Fix it like a life depended on it, because it just may.
  3. Accept that not everyone will get it.
  4. Do this every chance you get.

 

Many of us have stories about how we’ve taken opportunities to innovate. Here’s mine. When I was a second-year resident in the ICU back in 1994, we had a patient with HIV infection and necrotizing pancreatitis, requiring an open abdomen with three times a day sterile dressing change. These operations were performed in the ICU where the patient was left with an open abdomen with the pancreas which had exploded with inflammation was packed. The setup was quite hazardous because all the fluid splashing around was infected with HIV, occasionally bloody. But, it wasn’t just a hazard, it was a drudgery. Frustrated with the process, I came on the idea of inserting chest tubes over the packing and under the sticky adhesive drape, and then placing these on suction. I achieved a seal, and the ICU nursing staff was pleased with the invention. Thinking that I could escape the day without another hazardous dressing change, I took the time to pat myself on the back. Of course, I was called stat to the ICU and was dressed down by the head of the ICU for being both lazy and cavalier with the risk to the patient. Interestingly, though, a company came out several years later with a strikingly similar idea, and now negative pressure wound therapy is the standard of care in such situations. In fact, it’s a multi-billion dollar industry.

 

Of course, money shouldn’t be the sole motivation for innovation. I was motivated by doing less work, reducing the contamination threat for the ICU nurses, and improving care. Many of the best innovations in medicine help the physician care for the patient more efficiently, with better results, and with less suffering. Similarly, the Cleveland Clinic was conceived when American physicians and surgeons, while camped in the vasty fields of northern France during World War I, came to the realization that working collaboratively in a big tent across specialties and disciplines created great efficiencies and rewards, particularly in patient outcome. This innovation, encapsulated in the words “to act as a unit,” brought to the world the first multi-specialty clinics.

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Here’s one last, more-recent example. I am frequently called emergently to an operating room to help control bleeding. Typically, these requests are from surgeons here at the Clinic working on severely scarred, radiated, or previously operated tissues. The typical routine is to dig out the vessel and clamp it, which is challenging because dissecting out the vessel can cause further injury to the vessel with more bleeding. I realized that a circular compressor would control bleeding and provide space for placing a repair suture (figure). When it works, it’s surprisingly easy. You can try it yourself; if you get bleeding from a vein on the skin, compress it with the ring handle of a clamp. This idea has gone to our Innovations office, is now patent pending, and is on track to be manufactured.

 

We became the dominant species on this planet through the trait of innovation. We could not migrate and survive on all the continents by waiting to grow fur, wings, or gills. Rather, we sallied forth, and we invented our way through deserts, mountains, ice fields, oceans, and jungles. Yet, inventiveness is not common, and it’s too often viewed poorly as a close cousin to cunning, or even sorcery. Innovation also threatens the status quo, because it brings change, and with that obsolescence. Innovation is risky, and the stakes are even higher in medical innovation. But, it’s also the only way we will solve what ails us.

 

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  1. Michael Park, MD is a vascular surgeon at the Cleveland Clinic and a 2017-2018 Doximity Fellow. He will be moving abroad to be chief of vascular surgery at Cleveland Clinic Abu Dhabi.
  2. Published Op-(m)ed on Medium link