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.

When Better is Better Than Good

original bypass

The dictum that better is the enemy of good is one of the old chestnuts carried around surgery training forever. It is an admonition against an unhealthy perfectionism that arises from either vanity or self doubt, and in the worse cases, both. The typical scenario is a surgeon trying to make a textbook picture perfect result and finding the patient’s tissues lacking, will take down their work to make it better, and repeat this process while the patient and everyone else in the room lingers.

Trying to avoid this, many surgeons will try to avoid any difficulties -the bad patch of scar tissue, irradiated body parts, areas of prior infection. But the mental contortions involved in avoiding “perfect” can result in actual physical contortions that in the end don’t pay off in good enough. I have not been immune to this, and I don’t think any physician or surgeon can honestly say they haven’t experienced some variation on this.

This patient is a younger middle aged man who in his youth experienced a posterior dislocation of his left knee, resulting in an arterial transection. This was repaired with an in-situ graft. Subsequently, he had complications of osteomyelitis and had his knee fused after resection of his joint. He did well with this bypass for several decades, but it finally failed several years ago, and a new one was created (image above).

Rather than directing the graft in line as in the previous one, this was was taken from a medial exposure of the femoral artery and tunneled superficially around the fused knee to coil lateral, ending in the anterior tibial artery.

This graft in turn thrombosed and was lysed by the outside surgeons and underwent serial interventions of proximal and distal stenoses at the anastomoses. The patient, when I met him, was contemplating an above knee amputation as a path to returning to work as a nurse in a rural hospital.

While there should be no reason long bypasses should do any less better than short bypasses, I do have to say these things about this patient’s bypass:

  1. No vein is perfect and the longer your bypass, the more chances you will have that a segment of bad vein will end up in your bypass
  2. Turning flow sharply can cause harsh turbulence. Turbulence can cause transition of potential energy into kinetic energy which acts to damage intimal, resulting in intimal hyperplasia.
  3. Thrombosis is a sure sign that your graft is disadvantaged, and the longer the period of thrombosis, the longer the intima “cooks” in the inflammatory response that accompanies thrombosis, making the vein graft even more vulnerable to subsequent intimal hyperplasia, thrombosis, or stricture.
  4. A high flow, small diameter vein graft entering a larger, disease free bed results in more turbulence but also Bernoulli effects that cause the graft to close intermittently, vibrating like one of those party favors that make a Bronx Cheer (a Heimlich valve). This is the cause I think of the distal long segment narrowing on this graft.

This patient was decided on amputation when our service was consulted, and after reviewing his CTA, I offered balloon angioplasty as his symptoms were primarily of paresthesia and neuropathic pain. I used cutting balloons and got angiographically satisfactory results.

intervention

The patient, although he admitted to feeling much better, was sad. He relayed that he had felt this way several times before, only to have his life interrupted by pain and weakness signaling a restenosis.

 

A direct graft would require about 10 centimeters of vein
 
It was only a month later when I heard the patient had returned with the same symptoms. He wasn’t angry nor full of any “I told you so” that frankly I was muttering to myself. Reviewing his CTA, he had restenosed to a pinhole. The vein, to use a scientific term, was “no good.”

The other interesting finding was that he had an abundance of very good vein. Following surgical dictum, his original and subsequent surgeons had used his vein from his contralateral saphenous vein. His right leg, fused at the knee, lacked a good calf muscle pump action. While there were no varicose veins, the greater and lesser saphenous veins were large and generous conduits, at least by 3DVR imagery, confirmed on duplex (image below, white arrows).

veins
3DVR showing presence of potential conduit

The extant arteries were smooth and plaque-free. I decided to harvest his lesser saphenous vein and through the same incision expose his distal superficial femoral artery and tibioperoneal trunk. While I anticipated some scarring, I was confident that the sections of artery I wanted to expose were easy to access because of some distance from the fused knee.

IMG_6478
On left short saphenous vein was harvested then same exposure used to expose TP Trunk

The picture shows the exposure and reversed vein graft in-situ, using the segment of lesser saphenous vein. As in prior experience in redo surgery, you can never know if a dissection will be easy or hard simply based on fear or concern for breaking something. It’s not until you start bushwacking –carving through scar and dealing with extraneous bleeding will you learn whether it was easy or hard. You can only be certain it was necessary. The only hitch was the femoral artery while well exposed, was buried in scar, and I chose not to get circumferential control as I was fairly deep, and had avid backbleeding from a posteriorly oriented collateral that required a mass clamp of the deep tissues.

Will this work better? Don’t know but it has a good chance, and I think a better chance. It is a large vein oriented in a straight path over a short distance going from good artery to good artery. This is better theoretically than a long meandering bypass with smaller vein. 

The best last conduit is your own artery

  

 

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.