Tag Archives: bypass

Comment on “Incidence of Myocardial Infarction After High-Risk Vascular Operations in Adults” by Yen-Yi Juo et al. JAMA Surg. 2017

Question raised by the paper – MI incidence in high risk vascular surgery didn’t decrease despite advanced cardiac care pre-op (2.7% 30 day MI in 2009; 3.1% in 2014).
My comment on this paper – This study only analyzed high risk procedure includes open AAA and infrainguinal bypass. Endovascular intervention was not included so SHOULD NOT BE MENTIONED ANYWHERE IN THE ARTICLE.
This study has poor generalizability. It is retrospective study on a very unspecific database. NSQIP database lacks specifics on location of cross-clamping in aortic cases and detailed perioperative medical management. Study population is predominantly white, and criteria for MI was not specified and only included up to 30 days.
With the advancement of endovascular intervention, more AAA and TAAA are treated with simple or complex EVAR (branched or fenestrated). The more emergency procedure in open AAA cohort reflects the makeup of open procedure for AAAs, as more and more elective cases of AAA are done endovascular. Open aortic procedure are also becoming increasingly complex, as the simple AAAs with adequate infrarenal aneurysm neck size, length, morphology are treated predominantly by EVAR. The leftover ones with aneurysm neck angulation and large diameter, juxtarenal/pararenal AAA, etc comprise the open AAA intervention. Thus, one can extrapolate that the open AAA procedures are becoming higher risk with expected poorer outcomes. It is no surprise that there is significantly higher actual incidence of post-op MI in open AAA repair [3.0%] vs [1.9%] in infrainguinal bypass, which is more of an elective procedure with subacute patient presentation. Therefore, pre-op cardiac workup and optimization are paramount. However, one cannot associate endovascular intervention with poorer outcome. EVAR, if anything, has made repair of AAA and TAAA into a low risk procedure, without the need for general anesthesia or cross clamp, and made even the rupture of AAA a controllable incident. It has made the cases of AAA/TAAA that require open approach more morbid procedure, but broad perspective that include all AAA/TAAA treated open and endovascularly would likely reflect an improvement in long term outcome of these patients.

Axillo-hepatic-profunda bypass?

Say what?

That was my response when Dr. Linda Harris told me about her plan. She is the program director of vascular surgery here at University at Buffalo, and more importantly she is my mentor. However, I can’t help but second guess the words that were coming out of her mouth.

“Yap, I’ve done it before. It’s the only viable option we have left.”

Alright. Don’t have to tell me twice. I’m going to see this thing through.

The patient is a Caucasian female in her late 50s. She has extensive aorto-iliac occlusive disease, and status post past aorto-bifem bypasses that failed and salvaged with stents and fem-fem. The fem-fem then failed and more stents were placed. She is now presenting with postprandial abdominal pain, weight loss and food fear, a classic triad of chronic mesenteric ischemia, as well as right sided lower extremity rest pain. Her aorta had extensive calcification throughout, including the supraceliac region, and there was no inflow site adequate for an aorto-mesenteric bypass. Fortunately, extra-anatomical bypass was never done for her in the past. Duplex revealed retrograde flow at common hepatic artery and CT revealed a patent hepatic artery despite severe stenosis at other splanchnic vessels. CT with runoff showed a patent right profunda artery with distal collateralization.

So the outline of bypass was something like this:

In the end, the patient gained palpable right lower extremity pulses and audible doppler signal throughout the branches of her SMA.

Some takeaways and pointers from this procedures are listed below:

  • Tunneling via midaxillary line if axillo-fem bypass only; tunneled deep to the pectoralis major and into the abdominal cavity under the costal margin if axillo-mesenteric bypass. In this case, the tunneling was via right midaxillary line but one of the bifurcated limb of graft was swung over the costal margin into the peritoneal cavity.
  • Third part of axillary artery after emerging from pec minor was used for inflow. This part of axillary artery gives simpler exposure (need to split pec minor/major if more proximal part is used).
  • Ringed PTFE graft for simple procedure (no need for vein harvest) and it is protected from kinking compared to GSV.  However, if bowel were infarcted then GSV preferred due to less likelihood of graft infection.
  • Greater omentum was first sutured around the entry point of the graft into the abdomen and then invaginated over the main body of the graft using interrupted Vicryl suture to exclude it from peritoneal cavity.
  • Interposing vein collar/cuff was not used, but it might have been a good idea…
  • The smaller size of graft is preferred (8mm). A larger diameter will result in slower velocity, increasing the buildup of pseudointima.
  • Endarterectomy of visceral arterial ostium not possible due to no clamping site at supraceliac aorta due to calcification. However, this might be an option if clamp site as present (or do a thoraco-hepatic-profunda bypass)
  • Endovascular intervention was out in this case due to prior aorto-bifem (thrombosed proximal CFA) and supraceliac calcification (rendering brachial approach difficult).
  • Axillary inflow might just serve as a bridging procedure to allow temporary clinical stabilization and definitive reconstruction at a later date. However, in this patient it will likely serve as definitive repair.
  • Renal arteries were patent in this patient, so even though aortic plaque usually originates at the infrarenal aorta, this patient just had ostial lesions at the visceral branches and atherosclerosis of supra celiac region, which represent a rarer progression of aortic atherosclerosis.

If one knows what she is doing, one can achieve great things in what seems to first timers as really funky ways.

Infra-popliteal bypass – longest case by far

Below is a short and sweet version of the longest surgical case thus far in my short and sweet medical career:

Patient is a 47 years old Caucasian male with IDDM, past stroke, past DVT, PVD, and HTN. He has a dry gangrenous ulcer in the plantar aspect of his right first metatarsal, and occlusion of anterior tibial artery. He is scheduled to undergo femoral to peroneal artery bypass with great saphenous vein.

Image result for popliteal to peroneal bypass

Common femoral artery cut down was performed first for pre-op angiogram; this was partially due to the uncertainty of where exactly the occlusion is and patient’s vascular anatomy. We saw completely occlusion of the anterior tibial artery and distal portion of the posterior tibial artery after the takeoff of peroneal artery. The popliteal artery and peroneal artery were patent. Next, the deep compartment of the mid calf was dissected from the medial leg to skeletonize the peroneal artery. We also skeletonized the popliteal artery because we decided convert the procedure to popliteal to peroneal bypass. Afterwards, we proceeded to looko for the GSV in the medial malleolus, but the vein was too small (lower threshold is 3mm in diameter, but ours was much less). Therefore, we retrieved the GSV from up to, following the sephaneous-femoral-junction. Finally, we heparinized, dilated and anastomosed the venous conduit. Due to the difficult, delicate dissection of the deep compartment of the leg, difficulty exposing the GSV, the changing of procedural planning intra-op, and not having the imaging study pre-op made the whole case around 10 hours. Luckily, the goal of re-perfusing the foot as accomplished, with biphasic pulse on doppler post-op.

The take away from this case is for me is the importance of being prepared before diving in. The fascinating part about vascular surgery for me is the options of choosing your strategies for the battle – like a tactician – may it be open, endovascular, medical, or expectant management. The choices branch out further with each category of treatment. However, in this case since we didn’t have a strong plan going in, we were not able to change our plan smoothly on the fly. The result? 10 hours of anesthesia for patient instead of 6. On a good note, there were lots of dissections and anatomy structures that I learned, rather serendipitously I would say though…

Finally, I learned the luxury of having a stool in a marathon case.