Exovascularist’s Dilemma: Where Is Our LIMA to LAD

Posted on by docpark

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

The best last conduit is your own artery

Posted on by docpark

  

 

The patient is a 60 year old with severe peripheral vascular disease. Risk factors included smoking, hypertension, and type I diabetes. The patient had developed gangrenous eschar over toes 1, 2, and 3. He had had prior bilateral femoropopliteal bypasses with saphenous vein, which was occluded on his symptomatic side, and stent grafts had been placed on his distal femoral to popliteal artery, but these were occluded. He also had chronic edema with some early lipodermatosclerosis and pitting edema. He was emaciated and had a low prealbumin. 

CTA showed diffuse aortoiliac atherosclerosis with a severe stenosis in the proximal common femoral artery.

 

The femoropopliteal stent grafts were occluded but the popliteal artery reconstituted into a diseased set of tibial vessels -only the posterior tibial artery remained patent into the foot and remained as a target.

  

Preoperative angiography corroborated the CT findings.

  

  

 

The preoperative vein mapping suggested there was an acceptable anterior thigh tributary vein and marginal segments of vein below the knee. Arm vein was available as well. 

My plan was to explore the veins on his legs and expose his CFA and BKPOP along with the posterior tibial artery. If the veins were inadequate, I would proceed with open endarterectomy of the common femoral artery and remote endarterectomy of the external iliac artery and stenting of the diffusely diseased common iliac artery and remote endarterectomy of the femoropopliteal segment above the stent to use as inflow for a shorter bypass with the vein we had. 

Exploration showed that the anterior thigh vein was thin walled and became diminutive in the mid thigh. The infrageniculate veins were numerous and too small. I thought I might have enough for a short bypass from a recanalized mid SFA. 

The remote endarterectomy of the external iliac and stenting of the common iliac went without complications. I do this over a wire to ensure access in case of rupture. A postop CTA shows the results in the aortoiliac segment.

  

Remote endarterectomy of the SFA went smoothly but was held up by calcified plaque above the occluded stents. 

SFA plaque

I cut down on the SFA and found that the vein from the thigh would be short. I mobilized the plaque and re engaged the Vollmer ring and was able to dissect the stents. By starting another dissection from the below knee popliteal artery, the stent was mobilized and removed.

Viabahn stent grafts, occluded, removed

The figure below shows the procedure angiographically. I used a tonsil clamp to remove the mobilized stents.

Left, prior to remote endarterectomy, Mid -stent removal, Right -completion

The common femoral and mid SFA arteriotomies were repaired with patch angioplasties. The infrageniculate popliteal arteriotomy was used as inflow to a very short reversed vein bypass with the best segment of thigh vein to a soft posterior tibial artery.

Before and after of thigh segment

 

Before and after, the CTA on right is late in phase and has venous contrast.

Before and after, centerline.

The patient had a palpable posterior tibial artery pulse at the ankle. CTA predicted the plaque found in the tibioperoneal trunk which compelled me to do the short bypass. In my experience, remote endarterectomy, sometimes with short single segment bypass, successfully restores native vessel circulation without need for lengthy multisegment arm vein bypass. Remote endarterectomy of the external iliac artery avoids the difficult CFA plaque proximal end point that often requires stenting across the ligament down to the patch. Only a single common iliac stent is required. I generally anticoagulate these patients with warfarin, especially if they are likely to resume smoking or have poor runoff. I hope to show this is the equal of multisegment vein bypass, and superior to it by virtue of avoiding long harvest incisions which are the source of much morbidity and now readmissions which are penalized.

     

Popliteal Endarterectomy and Short Bypass in Lieu of Multisegment Vein Bypass

Posted on by docpark

The patient is a very pleasant elderly lady who had a prior EVAR complicated by graft limb thrombosis treated with thrombectomy. She recovered from that but subsequently developed ulceration of her left ankle. She had been sleeping in a chair because it hurt her to sleep flat –her leg and foot would burn with pain. A wound care center had tried an Unna’s boot, but it caused her worse pain, and the ulcer increased in size. At admission, she had an exquisitely tender, edematous leg and ankle with a large ulcer weeping edema fluid. There were no palpable pedal level pulses.

I admitted her for workup and treatment of a mixed etiology arterial and venous ulcer.

These are patients for whom rest pain is relieved by avoiding recumbency, but with prolonged sitting, as in this lady, edema accumulates and starts to leak, creating an ulcer of the venous type, in the medial ankle (gaiter) region. These don’t resolve without addressing the underlying cause which is the arterial insufficiency. Fixing the arterial insufficiency then allows for leg elevation and compression. For the trainees, venous ulcers almost uniformly heal with Unna’s boot therapy. Elevation should relieve discomfort in venous ulcers. Neither of these occurred and raises the suspicion of arterial insufficiency.

At admission, her PVR’s showed severe popliteal/tibial level occlusive disease. CTA was performed and it showed the common femoral and superficial femoral arteries to be patent but plaque occluded the popliteal artery and origins of the tibial vessels.

The only patent runoff was via her peroneal artery. Centerline evaluation of the CT scan was performed, with manual centerline created through the occluded segment of popliteal artery. I find this useful for planning endarterectomy and bypasses, and with attention to detail, images that are the equivalent to tibial angiograms come to life. This is a centerline through the femoropopliteal to peroneal system.

Vein mapping revealed a paucity of good vein –only a short segment in the proximal thigh on the left and for a short segment on the right. Stress testing revealed that she was good to moderate risk. Isolated popliteal occlusive disease with poor tibial runoff, while feasible for intervention, is not likely to be durable. Multisegment vein bypass on the other hand, using at least three segments, meant a long operation for this frail old lady and a prolonged recovery. I felt that popliteal endarterectomy and distal SFA remote endarterectomy offered a good option for revascularization, with either a patch repair or a short bypass to the peroneal artery. The backup plan was composite vein, but it was unlikely to be needed because the plaque was not the calcium pipe type plaque that does not endarterectomize well.

The patient was positioned on the table supine. The short segment of proximal greater saphenous vein was harvested –it was of suitable caliber, but below its first major tributary point, the veins was thick walled and small. The total length was about 10 cm. The below knee popliteal space was opened and the popliteal through tibioperoneal trunk bifurcation was exposed. Antegrade puncture of the common femoral artery allowed for arteriography and it showed the occlusion at the knee with reconstitution of the peroneal artery.

The popliteal artery was opened and endarterectomy of the occlusive plaque was performed. Retrograde remote endarterectomy (EndoRE) with Vollmer rings was performed to the mid superficial femoral artery where on the CTA the calcified plaque ended. The technical point about retrograde EndoRE is that the ring catches as the plaque gets larger more proximally, and has to be swapped out for a larger ring. Ultimately a 7mm Moll Ring Cutter was used to cut the plaque (picture below, arrow to more proximal SFA plaque).

The plaque, because it is larger the more proximal you go, came out with some difficulty via the below knee popliteal artery. This is not a great concern if it won’t come out –you merely have to cut down on the SFA in the thigh to fish out the plaque. In this case, it was not necessary, and it came out in several pieces, facilitated by the cutter which was used to graft the plaque in segments to retrieve it. Unfortunately, I don’t have a picture from this case of the plaque, but I have inserted a popliteal endarterectomy plaque image below from an prior case of popliteal endarterectomy.

This restored pulsatile flow to the below knee popliteal artery. Opening the artery down to the tibioperoneal artery revealed the artery to occluded and I took the endarterectomy to the peroneal artery origin and everted a short segment of posterior tibial plaque. The peroneal artery was large and would accept flow readily, so I chose to bypass to it using the short segment of saphenous vein that I had harvested for a possible patch or short bypass. The vein was reversed and anastomosed in the usual manner. Arteriograms are below.

The flows were multiphasic. I attempted to cross the posterior tibial occlusion but ended up with contrast extravasation, therefore stopped with this repair. The patient’s wounds were closed and ulcer cleansed and compressed. In the week postop, she healed her ulcer and her two short incisions, and felt good enough to go home with homecare. Her noninvasive studies and duplex confirmed the patency of her revascularization, and there was a multiphasic signal in her posterior tibial artery as well as peroneal.

In the handful of patients I have managed this way, either with popliteal endarterectomy and patch or short (micro) bypass, they have stayed patent past a year, but do require surveillance. Because of her frailty and unsteadiness of gait, I chose not to anticoagulate with Coumadin which is my usual practice, but have her on Plavix and aspirin.