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acute limb ischemia bypass chronic limb threatening ischemia cli clti cost innovation hybrid technique limb salvage Practice techniques vascular lab

MacGyvering as tactical innovation -set your mind free.

The patient is a 70 year old man with risk factors of cigarette smoking, type II diabetes mellitus, hypertension, and hypercholesterolemia who presents with rest pain and gangrene of the tip of his left great toe. Several weeks prior to this, he went to his pharmacy and received a flu vaccination and picked up over the counter topical medication for an ingrown toenail. who developed pain from an ingrown toenail. Several weeks later, the tip of his toe blackened and the pain became unbearable and he came to the hospital.

No pulses, dry gangrene of tip of toe

Physical examination was notable for the dry gangrene affecting the distal phalanx of the left hallux. There was a left femoral pulse, but nothing was palpable below. His forefoot was cool and painful and this pain was relieved with dependency.

Pulse volume recording showed a drop in flow across the left knee and flate waveforms at the ankle, foot, and digits. The ABI was zero. WIfI 2 3 2, Stage 4, potential benefit of revascularization high (reference 1). CTA was performed and revealed patent aortoiliac segment, patent common femoral and profunda femoral arteries, with occlusion of the mid to distal SFA, reconstitution of the above knee popliteal artery with 2 vessel runoff via a patent posterior tibial and peroneal arteries.

CTA VR Reconstruction Shows Reconstitution of AK POP and 2V Runoff via PT and Peroneal Arteries

The centerline reconstructions, adapted from aortic planning, lets me determine the character of the arteries for size, calcification, stiffness, collateralization, and length of occlusion. This was had low density and given the timecourse of the events -from claudication to gangrene, and the lack of collaterization implying an acute process possibly on a chronic lesion, I felt there was likely to be some thrombus burden over a chronic plaque across Hunter’s Canal with occlusion of the geniculate arteries. Usually, when the occlusion is chronic, femoropopliteal occlusions of this type come with an ABI of 0.5-0.7, not 0.

GLASS FP:3, IP: 0 Stage II: Intermediate complexity disease

Global Limb Anatomical Staging System (GLASS) Classification of CLTI (reference 2) through the easy to use SVS calculator came out Stage II: Intermediate Complexity. I had the good fortune of being in the audience when GLASS was presented to a rapt audience in Lyons, France, by Dr. John White in 2017, at the ESVS meeting. I include it because Dr. Devin Zarkowsky on a tweet that generated this post wanted WIfI and GLASS. WIfI I find helpful. GLASS I am still figuring out, because it tends to tell me what I already know: this is a lesion of intermediate complexity that could go either way to open or endovascular.

Treatment options include:

  1. Endovascular -starting with POBA and escalating to various additional therapies such as stents, covered stents, DCB, drug coated stents, atherectomy, thrombectomy, thrombolysis (then any of the previously mentioned).
  2. Bypass with PTFE
  3. Bypass with vein
White Arrows Show the Excellent GSV

The data tells us so far that open or endovascular is broadly equivalent, but experience guides me. For rest pain, any incremental increase of flow will do, and it does not necessarily have to be in-line. For healing major tissue loss, there really can’t be enough flow. Bypasses with good runoff deliver a lot of flow. Bypasses with vein have great longevity and the shorter they are, the longer they last.

So is long patency important? Numerous studies have shown that patency does not impact limb salvage or amputation free survival, going to BASIL Trial (reference 3), but even stretching back to Dr. Frank Veith’s advocacy of PTFE bypass to infrageniculate targets (reference 4), patency does not add to limb salvage beyond the initial wound healing. The patency of a PTFE bypass to a tibial target is less than 20% at 5 years, but the limb salvage rate is a laudable 80% plus, and this is repeated in numerous evaluations of POBA, stents, and every new technology that has accrued in the nearly 4 decades since that paper.

What does patency buy you? Less reinterventions. There is nothing worse to me than having to reintervene within a year or two of an intervention. When a bypass works well, the patients just come for a hello-how-do-you-do for years. The BASIL trial concluded that bypass operations were more expensive, and I dispute this. In 2021, operations were far less expensive than the latest energy weapon, their box you have to purchase, and the catheters you use once and throw away. The argument given by interventionalists is that bypass operations are disfiguring and ridden with complications and that argument holds water as there are many points where vascular surgeons fail or have largely stopped work on investigating and optimizing open surgery. What if bypass surgery could be brought to the level of dialysis access surgery in terms of invasiveness? What if groin complications could be minimized? What if long filleting-type incisions of the thigh and leg could be eliminated entirely? What if edema could be prevented or minimized postoperatively to prevent serous drainage and infections? If you focus on the art of bypass surgery and choose patients well, you can get a quick, minimally invasive bypass with the overall physiologic impact of a Brescia-Cimino AV fistula. After considering endovascular, I chose bypass.

This patient had on mapping excellent saphenous vein between 3-5mm in diameter. He had excellent skin and was not obese. A vertical groin incision could be avoided by making a skin line incision over the saphenofemoral junction and transposing it to the adjacent SFA which was patent. Skin line oblique incisions in the groin heal much better than the standard vertical incisions, and it is possible to mobilize and expose the saphenous vein using an appendiceal retractor and clipping the generous proximal thigh tributary. In this patient, the most proximal incision was well away from the inguinal crease, the generator of wound infections in the groin. Essentially, if there is no groin incision there can be no groin complication.

The distal vein is mobilized first before dropping on the above knee popliteal artery which is exposed through a separate incision. This is because the AK POP space is best exposed over the sartorius, and the vein in this patient was well below (posterior) to the sartorius. The vein was tunneled under the sartorius to the AK POP. With the in-situ technique, the proximal anastomosis is completed, then the valves lysed with a retrograde LeMaitre valvulotome. Doing, after two or three passes, the pulse was strong, and the flow strong enough to fling the blood beyond the foot -a key step. If there is no such flow, if there is a weak pulse, or poor blood flight, I do one more pass of the valvulotome then duplex for any large diverting tributaries and tie them off one by one until good flow is achieved.

I do not mobilize the entire vein (and tie off every collateral) unless I cannot do an in-situ technique. It defeats the purpose of this beautiful minimally invasive procedure.

Femoral artery to above knee popliteal bypass with in-situ vein

He recovered rapidly and was discharged home after a partial hallux amputation by podiatry. In followup, he was feeling better. All of his surgical wounds had healed. Duplex and ABI did find this:

Retained valve, very hard to see but present on B-mode, causing a hemodynamically significant stenosis, with ABI of 0.57

I took him to the angiosuite for repair of this retained valve. Rarely, retained valves occur after in-situ bypasses, but require generally unsatisfactory solutions involving either open valvulectomy and patch venoplasty or stenting of a virgin vein. Valvulotomy is possible, but generally described as an open procedure as well, but I had other plans.

Downstream of this retained valve were tributaries which could be seen on duplex, and therefore accessible with a micropuncture needle. This would then allow for placement of a 4F sheath, through which the LeMaitre valvulotome would pass unhindered, allowing for valvulotomy. I would use this session in the angiosuite to deliver embolization coils to the diverting tributaries as well.

Arteriography reveals a retained valve and diverting AVF’s
Retained valve catches the catheter sent up and over from the other side

LeMaitre is a unique company in that it focuses on vascular surgical operations and arises from the original product and reason for the company the eponymous valvulotome. Because it comes sheathed in a low profile catheter, it is immediately familiar to modern surgeons even though it was made in another century.

Cutting of retained valve with LeMaitre valvulotome​ using ultrasound guidance​

Cutting the valves involved passing the valvulotome several under fluoroscopy through a 4F sheath placed through the tributary seen above. After the valvulotomy, the diverting tributaries, only one of which drained quickly into a deep vein, were coiled. At the end of the procedure, a manual cuff was found and an ABI checked. It was now 1.05.

Diverting tributaries coiled

In 2015, the Oxford English Dictionary added McGyver as a verb -“Make or repair (an object) in an improvised or inventive way, making use of whatever items are at hand.” A television show from the 80’s and early 90’s, the main character, McGyver, was able to make useful tools out of what was available, allowing him to come out victorious, but usually just survive. It is a useful concept that is a must have in managing complex and dynamic situations. Just because it hasn’t been done before to your knowledge doesn’t mean that it isn’t a simple solution. I have only one ask that LeMaitre flip their blades around and design an ante grade valvulotome. Those who know what I’m getting at know what I am getting at.

The LeMaitre valvulotome allows for in-situ saphenous vein bypass, a prototypical hybrid vascular procedure from the 80’s that portended the endovascular revolution that followed. It is meant to be used intraoperatively, but because of its low profile, it can be applied.

I will allow that this second procedure likely makes any argument to cost moot, but numerous incisions and extra time in the OR is avoided. The patient now has a vein bypass that could last many years which diminishes the need for follow up procedures to maintain assisted patency.

We will be arguing this point for years even after BEST-CLI is presented. BASIL-2 just closed enrollment. Hopefully we will get some clarity.

Reference

  1. Mills JL Sr, Conte MS, Armstrong DG, Pomposelli FB, Schanzer A, Sidawy AN, Andros G; Society for Vascular Surgery Lower Extremity Guidelines Committee. The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System: risk stratification based on wound, ischemia, and foot infection (WIfI). J Vasc Surg. 2014 Jan;59(1):220-34.e1-2. doi: 10.1016/j.jvs.2013.08.003. Epub 2013 Oct 12. PMID: 24126108.
  2. Conte MS, Bradbury AW, Kolh P, White JV, Dick F, Fitridge R, Mills JL, Ricco JB, Suresh KR, Murad MH; GVG Writing Group. Global vascular guidelines on the management of chronic limb-threatening ischemia. J Vasc Surg. 2019 Jun;69(6S):3S-125S.e40. doi: 10.1016/j.jvs.2019.02.016. Epub 2019 May 28. Erratum in: J Vasc Surg. 2019 Aug;70(2):662. PMID: 31159978; PMCID: PMC8365864.
  3. Adam DJ, Beard JD, Cleveland T, Bell J, Bradbury AW, Forbes JF, Fowkes FG, Gillepsie I, Ruckley CV, Raab G, Storkey H; BASIL trial participants. Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicentre, randomised controlled trial. Lancet. 2005 Dec 3;366(9501):1925-34. doi: 10.1016/S0140-6736(05)67704-5. PMID: 16325694.
  4. Veith FJ, Gupta SK, Ascer E, White-Flores S, Samson RH, Scher LA, Towne JB, Bernhard VM, Bonier P, Flinn WR, et al. Six-year prospective multicenter randomized comparison of autologous saphenous vein and expanded polytetrafluoroethylene grafts in infrainguinal arterial reconstructions. J Vasc Surg. 1986 Jan;3(1):104-14. doi: 10.1067/mva.1986.avs0030104. PMID: 3510323.

Categories
acute limb ischemia humor limb salvage techniques training

Of Clot, Tofu, and Cheese

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

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

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

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

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

Diagnostic and Therapeutic

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

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

Conclusion

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

Categories
acute limb ischemia aortoiliac occlusive disease (AIOD) innovation limb salvage PAD skunk works techniques ultrasound

The shunt as temporary bypass -a modest proposal

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

brachial to femoral shunt sketch

 

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

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

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

simpsons head

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

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

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

radial to dp shunt
radial artery to dorsalis pedis artery shunt

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

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

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

Categories
PAD aortoiliac occlusive disease (AIOD) amputation BKA tibial revascularization limb salvage graft infection

Never say never

fem-at-bypass.jpgIf you work long enough, you will not only see everything, but you may end up doing something that you say you would never do. You will be confronted with a scenario that would test not just your skills but also your boundaries. The adage, never say never is a warning that all of us may face a choice -to remain rigidly consistent with some earlier proclamation or to excuse a little hypocrisy for the sake of the patient.

At one point in recent years, I saw a patient who had an axillary artery to anterior tibial artery bypass with PTFE (figure above). That was a kind of marvel to me, but my initial response was a bit of a sneer.

“Who does this?” I thought.

Giving it some thought, the rationale could have been to spare the patient from a hip disarticulation as the patient had had failed revascularizations and was occluded from the infrarenal aorta to the anterior tibial artery on that side. If you see such a thing, it sparks wonder as it feels both wrong and splendid at the same time because some surgeon had the audacity to pull it off. By the time I saw it, the patient had avulsed the proximal anastomosis, infarcted their leg to their thigh, and was headed for a hip disarticulation, four years after the creation of the bypass. Four years of patency!

It was no wonder I remembered this case when this middle aged man presented to our clinic with a gangrenous right third toe. He had diabetes, hypertension, CAD with prior PTCA, prior acute mesenteric ischemia with bowel resection with an SMA stent, CHF with moderately reduced EF, CKD, and aortoiliac occlusive disease treated in past with aorto-bi-iliac bypass, left to right fem-fem bypass complicated by graft infection requiring resection of the fem-fem bypass, with subsequent development of rest pain on left leg and gangrene on right leg. He had been told at his home institution that he required eventual bilateral hip disarticulations. At the time of consultation, he was minimally ambulatory, limited by severe pain. He had been this way for over a year.

On examination, he had heavy scarring in both groins from prior open incisions healed by secondary intention, a midline laparotomy incision. He had weak bilateral axillary and brachial artery pulses. He had no pulses in either leg. The right foot had gangrene of the distal phalanx of the third toe. The both feet were anemic and painful -the left foot had more dependent rubor. Pulse volume recordings were flat in both legs. TCPO2 was in the 20-40mmHg range at the thighs bilaterally suggesting reduced potential for healing an above knee amputation. Vein mapping showed no suitable saphenous vein in either leg. CTA (figure below) showed both external iliac arteries to be occluded or absent and the common femoral arteries to be occluded or missing bilaterally.

AngioRunOff 1.0 B20f

The left femoral bifurcation was preserved and the left SFA was patent into small underfilled tibial vessels. On the right, there was an isolated segment of profunda femoral artery that reconstituted from pelvic collaterals. The right below knee popliteal artery reconstituted and had underfilled but patent three vessel runoff (figure below).

AngioRunOff 1.0 B20f (4)
posterior view of right popliteal reconstitution

The patient was admitted for workup and treatment. Heparin drip was started. In the setting of rest pain, I find that heparin drip improves circulation and symptoms even though it shouldn’t. I don’t have a great explanation for this, but it does, and I would welcome comments. To better assess how much operation the patient could tolerate, a cardiac risk assessment was performed. He was deemed a moderate to severely elevated risk due to his EF of 35% but had a normal nuclear stress test.

The options I presented to the patient were
1. Hip disarticulations
2. Bilateral above knee amputations with a wait and see approach to hip disrticulation
3. Sympathectomy
4. Axillo-profunda or popliteal bypass on right and Axillo femoral bypass on left
5. Ilio-right popliteal and left femoral bypass.
6. Thoracic or supraceliac aorta to right profunda and left femoral bypass

Hip disarticulation is the bogeyman of leg amputations done for peripheral vascular disease. When done for trauma or cancer in young people, the ability to rehab and walk again is excellent. When done for tissue loss in elderly, non-ambulatory patients, the reported mortality of the operation rises to above 50%. It is usually posed as a lead in to comfort measures. The above knee amputations were not likely to heal despite the neither here nor there findings of the TCPO2 which is only good when the results or normal or dismally low. Sympathectomy is an option for those without options, but this patient still had options, I felt.

Any revascularization relies on the choice of inflow, outlow, and conduit. In endovascular revascularizations, the conduit is the previously occluded vessels, but in this instance, because of the infected grafts, there was neither continuity, nor a good option even if there was as the common femoral artery is a terrible recipient of endovascular therapy. The options then devolve to choosing an inflow. The axillary arteries are technically easiest to access and manage and form the basis of treatment of high risk patients requiring limb salvage who have no endovascular options. The axillofemoral bypass is given a bad reputation of having a poor patency, but the key is the quality of the vessels and the number of potential tension, compression, and kink points. I think the reason why the axillary to anterior tibial bypass lasted for four years in the first patient had to do with his immobility, and the pristine nature of the anterior tibial artery -the only patent vessel below his umbilicus. Here to, the inflow disease appears to have spared his right popliteal artery and his left superficial femoral artery.

The only compromise with an axillary artery inflow is the amount of potential flow. In a patient with a 6-7mm axillary artery, the amount of flow going to both an arm and a leg, and a lower torso, would greatly exceed the flow capacity of that vessel. The infrarenal aorta on this man is graft and is relatively inaccessible due to the prior laparotomy for acute mesenteric ischemia, signalling the high likelihood of adhesions. The supraceliac aorta is an excellent inflow source and I have had good results dissecting it out laparoscopically as it is often deep and narrow an exposure to try to dissect open -While the retroperitoneal tunneling can be tricky, it is not insurmountable and good bypasses can result (link).

IMG_3242

My eye focused on the left iliac graft which perfused the internal iliac artery on that side. The graft was generous, and likely a dilated 8mm graft, and could be exposed via a left lower quadrant retroperitoneal exposure (the transplant exposure). This would allow me to to then tunnel to avoid the terribly scarred groins. On the right side, the obdurator canal could be traversed into the postioer compartment of the thigh -a graft could be sent to the below knee popliteal artery with a side graft to the tiny profunda femoral artery. On the left, the graft could be tunneled laterally near the insertion of the sartorius muscle and onto the superficial femoral artery. All of the incisions would be made in virgin skin, the only redo dissection being digging out the left iliac graft while avoiding injury to the ureter.

So I proposed a ilio-popliteal bypass. Not quite an axillo-tibial bypass, but almost there. There was some karmic balance being restored by my taking decision. It would be with PTFE all around. I quoted a 5-15% risk of major morbidity and mortality, lifelong anticoagulation, and right third toe amputation. The patient agreed.

Sketch001
sketch of iliopopliteal and iliofemoral bypassrs

The operation was done in a hybrid suite, as should all limb salvage cases. The retroperitoneal dissection was challenging because of the heavy scar tissue around the well incorporated iliac bypass, but with patience, a clampable 3cm segment was achieved. I am a big fan of Wylie hypogastric clamps because they stay out of the way when placed in a tight narrow spot, and for that same reason, I prefer the Cherry supraceliac aortic clamp. They were designed by my mentor, Ken Cherry, and his mentor, Jack Wylie for this kind of operation. A few venous bleeders were easily handled with my ring compressors (below), and I hope to continue this chain of innovation, but I digress.

park clamp.jpg
a Park clamp

The bladder was dissected off the pubis to allow the graft to be tunneled to the right pelvis. A counter incision in the right lower quadrant abdomen and a mid thigh incision mobilizins the anterior compartment muscles to the posterior compartment allowed me to tunnel across the obturator foramen. The obdurator vessels need to be avoided or there will be bleeding. this mid thigh incision allowed exposure of the profunda femoral artery more proximally and allowe the graft to be tunneled anatomically to the below knee popliteal artery for anastomosis. A jump graft was taken off this graft on the thigh to the profunda femoral artery which was small and diseased -no more than 2mm in size. An axillary bypass to this profunda would be doomed to the compromised patency rate published for ax-fem bypasses giving them a bad name. The left superficial femoral artery was exposed and provided outflow to the left iliofemoral bypass which was tunneled far laterally under the inguinal ligament to avoid the scar tissue where the common femoral artery was.

There was immediately multiphasic signal in both feet on release of clamps. After closure of all the incisions and dressings, the right middle toe was amputated.

The patient recently came back for an 8 month followup. His grafts remained patent and he was walking without limitations. Given the high quality of the inflow (large iliac graft), and the amount of decent outflow -the right popliteal and profunda, the left superficial femoral and retrograde to the profunda, gives the patients some surety of longevity for his grafts. These grafts will need lifelong surveillance.

I have since opened my mind a bit about that axillary artery to anterior tibial artery bypass. When given the choice between comfort measures for an otherwise nonambulatory but alert patient and hip disarticulation with its attendant high risk, a bypass from a large axillary artery to a large, relatively disease free anterior tibial artery is not the worst thing that could happen. For that patient, it gave them 4 more years with their family, which in any measure, is priceless. To that patient’s family, that surgeon was a savior.

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

Zebras, not horses: popliteal artery entrapment syndrome

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

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

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

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

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

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

paes.png

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

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

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

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

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

pop patched.png

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

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

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

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

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

 

Categories
amputation aortoiliac occlusive disease (AIOD) BKA bypass Commentary complications limb salvage Lymphatic techniques tibial revascularization training Uncategorized Wounds

Exovascularist’s Dilemma: Where Is Our LIMA to LAD

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.

Lymph leak identified from saphenectomy incision (for CABG)

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.

Water goes downhill

Categories
AIOD aortoiliac occlusive disease (AIOD) complications EndoRE graft infection limb salvage remote endarterectromy techniques Uncategorized

Salvage: A different approach to graft infections in the groin

The principles of salvage are in rescuing valuable undamaged goods in the setting of catastrophe. This guided me when a patient was flown in from an outside institution to our ICU with a saline soaked OR towel in his right groin -he had had an aorto-bifemoral bypass for aorto-iliac occlusive disease a year prior, but had never properly healed his right groin wound which continued to drain despite VAC therapy and wound care. On revealing his groin, this is what I saw:

EndoRE in graft infection.002

A CT scan was sent with the patient but has been lost to time, and it showed a patent aorto-bifemoral bypass send flow around an occluded distal aorta and iliac arteries. The graft did not have a telltale haze around it nor a dark halo of fluid which signaled to me that it was likely well incorporated and only sick in the exposed part. The patient was not septic, but had grown MRSA from the wound which was granulating from the extensive wound care that had been delivered.

EndoRE in graft infection.009

I felt that it would be possible to move his anastomosis point more proximally on the external iliac in a sterile field (figure above), and then close, then endarterectomize the occluded external iliac artery after removing the distal graft, then after vein patching, cover the repair with a sartorius muscle flap. It would salvage the remaining graft and avoid a much larger, more intense operation which was plan B. To prepare for that, I had his deep femoral veins mapped.

The patient was prepped and draped, the groin was excluded by placing a lap pad soaked in peroxide/betadine/saline solution (recipe for “brown bubbly” liter saline, a bottle of peroxide, a bottle of betadine), and covering with an adesive drape. The rest of the abdomen was then draped with a second large adhesive drape. A retroperitoneal (transplant-type) right lower quadrant incision was made (below) and the external iliac artery and graft were exposed. As predicted on CT, the graft was well incorporated.

EndoRE in graft infection.003

The external iliac artery was opened and focally endarterectomized of occlusive plaque (image below). The adventitia had good quality despite the longstanding occlusion.

EndoRE in graft infection.004

The graft was mobilized and transected and anastomosed end to side to this segment of artery (below). Dissecting was made difficult by how well incorporated it was.

EndoRE in graft infection.005.jpeg

The wound was irrigated (with brown bubbly) and closed, dressed, and sealed over with the adhesive drape. The groin wound was then revealed and the graft pulled out (below).

EndoRE in graft infection.006

Remote endarterectomy using a Vollmer ring was used -in this case I didn’t use fluoroscopy given the short distance to the terminus of the plaque which i had mobilized in the pelvis.

EndoRE in graft infection.007

The plaque came out easily and was not infected appearing. It is shown below ex vivo.

EndoRE in graft infection.008

A segment of saphenous vein was harvested from the patient medially and the arteriotomy was patched. The sartorius muscle was mobilized and applied as a flap over this. The wound was irrigated with brown bubbly and packed open with the intention of VAC application.

The patient healed very rapidly and remains infection free. I had used this approach on several occasions in the past and twice more recently. It truly is salvage as it preserves the uninfected graft while never exposing it to the infection in the process of operating. It avoids having to remove the whole graft which then damages the left side -I have seen other surgeons take this approach elsewhere taking a all-or-nothing approach to graft infection to considerable morbidity to the patient. It avoids having to harvest deep femoral vein -another large operation to which the body responds truculently. The patient recently came by for his 4 year followup, still smoking, but legs preserved.

Followup At 4 Years

IMG_0657

The patient came back in followup -it has been 4 years since his infection was repaired. He was complaining of short distance claudication. His wound healed well and remains closed. CTA shows along with his short segment SFA occlusion which we will treat, a widely patent R. EIA (below).

CTA 4 year followup

The remote endarterectomy of the external iliac artery remains patent. Compare this to the preop CTA which I found and wasn’t available when I posted this case originally:

 

preop CTA_4

The chronically occluded EIA can be readily seen. The artery shown in the current CTA is that recanalized artery.

 

Categories
limb salvage PAD training vascular lab

Bypasses still work -a guest post from Dr. Max Wohlauer

pre-angio

angio text.png

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.

 

preop TBI.pngpreop-abi

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.

preop saph vein mapping.png

Max comments:

  • Compromised runoff on angio. Cutdown on AT and determined it was adequate target at start of case
  • Right fem-AT bypass
  • Re-do groin exposure
  • Translocated non-reversed GSV
  • Subcutaneous tunnel

 

The operation went well. Completion angiography was performed showing a patent bypass and distal anastomosis with good runoff.

completion angiography.png

A followup duplex showed patency of the graft.

postop duplex.png

Postop ABI’s showed excellent results:

Postop TBI.png

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.