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

Arterial Restoration -Something New, Something Old

Something that I recently promised Dr. James S.T. Yao, I will be working to publish on my stent removal and extended remote endarterectomy cases and techniques. Meanwhile, here is a talk.

Saving a patient from hip disarticulation with advanced hybrid inflow procedure and vein bypasses

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The patient is an elderly man who had bilateral above knee amputations after failure of aortobifemoral bypass grafts at an outside institution. Unfortunately, he had no femoral pulses and his amputation on the right broke down (image above). His left stump had erosion of his femur to the skin with rest pain as well, but was at least covered by skin for now. He was declared too sick for hip disarticulations and was sent to a hospice where he failed to pass away. After a year there, he was sent to us for an evaluation.

He was suffering from rest pain and had complete breakdown of the skin over his amputation stump. More worrisome was the development of gangrenous scrotal and decubitus ulcers which were small but persistent and also foci of pain. CTA showed the following:

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The aorta was occluded below his renal arteries. An AV fistula near his common femoral vein lit up his right iliac vein on the CT above. He had had a prior aortobifemoral bypass but this was occluded. Gratifyingly, it was anastomosed proximally end to side, giving us options. As with any revascularization, we had an inflow source -his aorta, and several potential outflow sources (CTA below, contrast filling iliac vein from AVF’s).

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In particular, his distal profunda femoral artery showed promise. Vein mapping revealed a short segment of basilic vein in his arm to use as bypass, but we needed inflow from the aorta.

I have come to appreciate two things about aortoiliac recanalization. First is that passing the wire antegrade is far likelier to stay in the true lumen at least in the aortic inflow segment -retrograde wire passage inevitably dissects the occlusive aortic plaque and reentry into the true lumen of the diseased aorta is just as challenging as in the leg. The second is vein bypasses have excellent patency in challenging conditions -you just need excellent inflow and an arterial bed to perfuse.

My plan was to cross the aortoiliac occlusion with a wire from the left arm. Once the right iliac system was entered, it didn’t matter if I was in a subintimal plane. The wire could be seated in the common femoral artery to access with a surgical exposure. Once this was done, my intention was to perform remote endarterectomy of the external iliac artery and stent from the aorta to the common iliac artery. The endarterectomized external iliac artery would be the inflow source of a later staged ilio-cross femoral bypass to revascularize his left AKA stump. The common femoral artery at its origin would provide inflow to a short vein bypass to his profound femoral artery.

The wire passed readily into the right iliofemoral system and a groin exposure and common femoral arteriotomy allowed me to retrieve the wire which had been passed from the left arm. A remote endarterectomy was performed over the wire which I do to ensure access in case the artery ruptures (specimen below).

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This allowed me to place a sheath into the right iliac system in the now reopened external iliac artery. Balloon angioplasty of the aortoiliac segment created working space for placement of balloon expandable stents from the infrarenal aorta to the common iliac artery, restoring an excellent pulse in the right groin.

The profunda femoral artery was encased in scar tissue, but following the occluded PFA from the CFA, I was able to expose an open segment and cut it open in the scar tissue. There was back bleeding, and I controlled the artery by placing a small Argyll shunt into the artery and reperfusing it from the recanalized right iliac system.

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The Doppler flow in the shunt was excellent, suggesting great outflow potential. The bypass was performed over the shunt with reversed basilic vein. Completion arteriography showed excellent flow.

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The amputation stump was debrided of dead bone and muscle and the graft was covered with a sartorius muscle flap.

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Before and after images are shown. The remaining open wound granulated well, and ultimately accepted a split thickness skin graft. His scrotal and decubitus ulcers healed as well (below at 6 months post op).

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His left AK stump subsequently degraded while he recovered so three months after this operation, he underwent a right external iliac to left profunda femoral artery bypass with cadaveric vein.

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I don’t like using cadaveric vein, but we really had no options. The right external iliac artery was approached through a right lower quadrant (transplant) incision and a punch biopsy of the artery revealed only normal adventitia on pathology. The EIA was soft and sewed well -essentially a normal artery brought back from the dead. The left profound femoral artery was large after endarterctomizing its origin and accepted the bypass flow well.

The mortality from hip disarticulation in the setting of gangrene and infection is very high, and I feel that standard approaches to this problem -prosthetic axillo femoral bypasses, thoracobi-femoral bypasses, in the setting of advanced infection and gangrene were unlikely to succeed. In over 1.5 years of followup, everything has remained patent, and the patient lives independently.

Extremity lymphatic leaks -a rare complication

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This patient had had an endoscopic saphenectomy for coronary bypass at another institution and had developed a wound infection that eventually healed, but developed a pore at the scope site that continued to drain clear fluid soaking an ABD pad hourly. This had been cauterized and sutured without improvement.

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The patient was taken to the operating room for dye lymphangiography and resection of the leak. The dye used was isosulfan blue which is lipophilic and is taken up by the lymphatics from the extra cellular space and pumped centrally within minutes of injection. The lymphatics are easily visible and the leak can be resected and the source vessels can be oversewn.

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The suction cannula is on top of a lymphatic that was feeding the pore and was oversewn. I have had this occur in the forearm as well after a braciocephalic fistula creation.

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The would was closed primarily. The lymphatics are evolutionarily the most primitive of our vasculature. They are gossamer threads often of single cell layer that have openings into the extracellular space and draw in fluid past bicuspid valves that bracket smooth muscle cells that periodically contract -a very primitive heart. The heart evolved from this mechanism.

It’s believed that multicellular organisms gained an advantage by maintaining an inner sea that was more organized and concentrated with nutrients than the surrounding sea, and to benefit all of the cells, it was necessary to circulate this inner ocean. The extracellular space is as porous as a sponge because that is what the ECM evolved from. Holding a wet sponge up in the air and watching the water go down with gravity is what happens when you stand up -edema. It is also why you can patiently and gently massage the extravasated saline from a displaced IV out of a hand and forearm. When the lymphatics stop pumping, the protein in the fluid eventually comes out of solution forming an insoluble solid -same thing that happens in cheese making when you add acid to milk -the hardened tissues of chronic lymphedema.

The pumping action is so efficient that injecting an amp of isosulfan blue into the web space between the toes subcutaneously will travel up the leg in about 5-10 minutes. There is a list of contraindications and precautions for its use, and hypersensitivity and anaphylaxis is reported to occur in up to 2 percent of patients.

This patient had primary closure and stopped leaking, after suffering from nearly a year of leakage.