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.
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.
Last Slides Should Pack a Punch
When I lecture to interventionalists (cough, cardiologists), I often end with some variation on the following:
1. The common femoral artery is the left main of the leg, so why would you ever leave a stent across the LCX?
2. Claudication is like stable angina, so is it okay to intervene on a long LAD CTO for stable angina?
3. Gangrene and ulceration are like STEMI and Non-STEMI, only you can’t take the dressing down on an infarcted heart three times a day and wash away the debris.
4. If a LIMA to LAD isn’t a failure and lasts many years beyond the best stents, how is a femoral to tibial bypass a failure?
5. Why is that [insert technology] is a failure in the coronary circulation but the latest and greatest thing in the peripheral circulation?
6. Reversible ischemia is well demonstrated in the foot by lifting it off the bed and watching the color change. It’s too bad for vascular surgeons we can’t build a giant white box around this test and have have the hospital build a center around it.
7. The ABI is a great test of cardiac risk, not so much for peripheral vascular disease.
8. Hybrid revascularization works for the legs in the same way it works for the heart -you maximize the hand that you are dealt.
9. The nitinol throne is not won without some cost.
10. One day, in the far future, someone will dig up an ancient human that is more nitinol, stainless, steel, and chromium, than bone, from the mitral valve out to the fingers and toes.
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.
Hello Abu Dhabi
In Medicine, We Can All Be Real-World Innovators
Innovation has become a virtue in the current culture. There is an evangelical fervor around it. What are TED Talks but tent revivals for nerds? What is the new Apple campus but a cathedral born out of the values of our time? Yet in elevating the more famous innovators and inventions to lofty heights, we lose sight of its very practical and useful daily application. Rather than treat it like inspiration from the heavens, we should approach it as a trait that we all share in.
To make it work for you, you have to think of it as a muscle, and put your reps in. Here are a few “training” tips:
- If someone (maybe you) complains about something that feels like drudgery, fix it.
- Fix it like a life depended on it, because it just may.
- Accept that not everyone will get it.
- Do this every chance you get.
Many of us have stories about how we’ve taken opportunities to innovate. Here’s mine. When I was a second-year resident in the ICU back in 1994, we had a patient with HIV infection and necrotizing pancreatitis, requiring an open abdomen with three times a day sterile dressing change. These operations were performed in the ICU where the patient was left with an open abdomen with the pancreas which had exploded with inflammation was packed. The setup was quite hazardous because all the fluid splashing around was infected with HIV, occasionally bloody. But, it wasn’t just a hazard, it was a drudgery. Frustrated with the process, I came on the idea of inserting chest tubes over the packing and under the sticky adhesive drape, and then placing these on suction. I achieved a seal, and the ICU nursing staff was pleased with the invention. Thinking that I could escape the day without another hazardous dressing change, I took the time to pat myself on the back. Of course, I was called stat to the ICU and was dressed down by the head of the ICU for being both lazy and cavalier with the risk to the patient. Interestingly, though, a company came out several years later with a strikingly similar idea, and now negative pressure wound therapy is the standard of care in such situations. In fact, it’s a multi-billion dollar industry.
Of course, money shouldn’t be the sole motivation for innovation. I was motivated by doing less work, reducing the contamination threat for the ICU nurses, and improving care. Many of the best innovations in medicine help the physician care for the patient more efficiently, with better results, and with less suffering. Similarly, the Cleveland Clinic was conceived when American physicians and surgeons, while camped in the vasty fields of northern France during World War I, came to the realization that working collaboratively in a big tent across specialties and disciplines created great efficiencies and rewards, particularly in patient outcome. This innovation, encapsulated in the words “to act as a unit,” brought to the world the first multi-specialty clinics.
Here’s one last, more-recent example. I am frequently called emergently to an operating room to help control bleeding. Typically, these requests are from surgeons here at the Clinic working on severely scarred, radiated, or previously operated tissues. The typical routine is to dig out the vessel and clamp it, which is challenging because dissecting out the vessel can cause further injury to the vessel with more bleeding. I realized that a circular compressor would control bleeding and provide space for placing a repair suture (figure). When it works, it’s surprisingly easy. You can try it yourself; if you get bleeding from a vein on the skin, compress it with the ring handle of a clamp. This idea has gone to our Innovations office, is now patent pending, and is on track to be manufactured.
We became the dominant species on this planet through the trait of innovation. We could not migrate and survive on all the continents by waiting to grow fur, wings, or gills. Rather, we sallied forth, and we invented our way through deserts, mountains, ice fields, oceans, and jungles. Yet, inventiveness is not common, and it’s too often viewed poorly as a close cousin to cunning, or even sorcery. Innovation also threatens the status quo, because it brings change, and with that obsolescence. Innovation is risky, and the stakes are even higher in medical innovation. But, it’s also the only way we will solve what ails us.
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- Michael Park, MD is a vascular surgeon at the Cleveland Clinic and a 2017-2018 Doximity Fellow. He will be moving abroad to be chief of vascular surgery at Cleveland Clinic Abu Dhabi.
- Published Op-(m)ed on Medium link
Nutcracker Syndrome: The Renal Vein Transposition
Case Report
Patient is a 43 year old woman who had been having bouts of severe left sided abdominal pain for several years with worsening episodes of nausea and vomiting resulting in several visits to the emergency room. She has also had microscopic hematuria. Gastrointestinal workup including gastric emptying study, esophagogastroduodenoscopy and colonoscopy were negative, as was a workup for kidney stones. Eventually she was referred to my clinic for management of nutcracker syndrome. She denied lower abdominal pain nor excessive menstrual bleeding.
On examination, she was tender over the left kidney and flank. Laboratory examination was positive for microscopic hematuria. CT venography (below) showed an obstruction of her left renal vein by the superior mesenteric artery. Drainage via gonadal vein was not demonstrated, and no pelvic varices or complex of retroperitoneal veins was apparent.
Duplex showed the narrowing in the left renal vein and spectral Doppler showed elevated velocities across the compression caused by the superior mesenteric artery (below). The collecting system was not obstructed.
Treatment options included endovascularization with a large stent in the left renal vein, left renal vein transposition to a lower position on the inferior vena cava, left renal autotransplantation, and left nephrectomy. Stent placement comes with a degree of risk for cardiopulmonary embolism which may require a sternotomy to fish out an errant stent. The risk for this in the US is because the largest nitinol stents available are 14mm in diameter which might result in undersizing in a vein that could easily dilate to well over 20mm. Larger nitinol stents for venous applications are available in Europe but currently are not approved in the US (yet). Wall stents, while certainly wide enough, have the problem of being long and stiff when not fully deployed. A 22×35 Wall stent may be 50mm long if deployed inadvertently into a tributary vein or contrained at the narrowing. Because it slides easily, passing balloons in or out can cause it to slip out of position. Because this stent elongates when compressed and packed, deployment is challenging and it is prone to “watermelon seeding,” a set up for embolism. It does have the virtue of easy reconstraining.
My friend and recent host for Midwest Vascular Surgery Society Travelling Fellowship, Dr. John V. White, in Chicago, seems to have solved this problem by a multistep process of predeploying a temporary suprarenal IVC filter, deploying a stent (whatever fits), leaving the filter as a protection against stent migration for 4 weeks until the stent permanently seats itself through scarring/intimal ingrowth, then removing the filter.
I chose to perform venography and renal vein transposition. The patient was placed in a supine position on a hybrid angiographic operating room table and her right femoral vein was accessed. She was placed in 15 degrees reverse Trendelenberg which is about the upper limit possible. Venography below.
After heparinizing and clamping, the renal tributary was taken with a 5mm cuff –this would ensure proper length without narrowing the IVC.
The vein was anastomosed and flow was excellent by pulse Doppler.
She recovered well but had a longer stay because of an ileus, being discharged on day 5. Because she lived at a distance, and came back for followup the following week prior to boarding a plane for home. She no longer had the left sided abdominal pain and there was no hematuria. CT showed excellent drainage through the transposed vein.
Followup will be periodic (6 monthly) renal venous duplex from home. Given that there was minimal tension on the repair, I expect this to do well.
Discussion:
Nutcracker syndrome is one of the many unfortunate consequences of our bipedal lifestyle. The small intestines hang like baggy sausages off the branched stems of the superior mesenteric artery (SMA), and in some individuals, the SMA compresses the left renal vein against the aorta. The left renal vein receives up to 12-15% of cardiac output via the left kidney, and with outflow obstruction, drains the blood through small collaterals. The renal venous hypertension results in swelling of the left kidney with subsequent left renal colic -with flank and abdominal pain, nausea, and vomiting. There is hematuria which can be gross or microscopic. With drainage via an incompetent gonadal vein, varicoceles can occur with discomfort in men and pelvic varices with pelvic congestion syndrome can occur in women.
Diagnosis is challenging because it is one of the relatively rare non-gastrointestinal causes of abdominal pain (table).
- Mesenteric ischemia
- Median arcuate ligament syndrome
- Nutcracker syndrome
- Neuromuscular
- Urolithiasis
- Inflammatory aortitis/arteritis
- Hypersplenism
- Portal hypertension
- Arterial aneurysm
- Infections
- Pelvic Congestion Syndrome
- Endometriosis
- Hernias
A history of left sided abdominal pain, flank pain, nausea, vomiting, associated pelvic pain, and episodes of hematuria are diagnostic. Examination is typically positive for left renal tenderness and flank tenderness. Laboratory examination include urinalysis for hematuria. Duplex, while technically challenging, will show renal venous compression with velocity elevation or loss of respirophasicity, CTA will typically show obstruction of the left renal vein with filling of collaterals, as will MRV.
Venography should be done in a stepwise manner (White protocol) to fully demonstrate the maldistribution of blood. That is the key word, maldistribution. I learned from my fellowship with Dr. White that performing venography in as upright a position as possible recreated the pathophysiology, the physics, particularly for pelvic congestion and nutcracker. Remember, this is a disease of bipedalism, of upright posture. Many negative studies done supine become positive, as the contrast will fall to where it prefers to go. As I have stated in the past, on the venous side, demonstrating drainage has different imaging needs than demonstrating flow. Pathologic venous drainage has three characteristics:
- Varicose veins develop as an end stage process
- Reversal of flow or reflux is demonstrated, particularly into small tributary veins
- The midline is crossed in these usually small, now larger, collateral veins
While pressure gradients are nice if they are large, they are difficult to assess when they narrow to 1-2mmHg, particularly if they vary with cardiac cycle and respiration. Because we are assessing drainage, the distribution of contrast and the direction it goes is particularly important, and far more sensitive than pressure measurements.
Venography was done per a modification of Dr. White’s protocol for pelvic congestion:
- Steep reverse Trendelenberg
- Hand injection 10mL half diluted contrast, gently as to not create false reflux
- Runs with catheter in left EIV, right EIV, left renal vein, right renal vein
- With pelvic congestion workup, add selective bilateral gonadal and internal iliac veins.
I have started transposing gonadal veins when they have enlarged from chronic reflux (link, ref 2). Renal vein transposition was chosen because her ovarian vein was competent and too small to transpose (ref 1-3). While the patency rate of stents in veins seems to be acceptable, long term data is unavailable. Also, venographic appearances are deceiving -see the in-vivo measurement of the left renal vein after dissection:
References:
- White, J. et al, Left ovarian to left external iliac vein transposition for the treatment of nutcracker syndrome. J Vasc Surg Venous Lymphat Disord. 2016;4:114–118.
- Miler R, Shang E, Park W. Gonadal Vein Transposition for the Treatment of Nutcracker Syndrome. Annals of Vascular Surgery 2017, July 6. in press. http://dx.doi.org/10.1016/j.avsg.2017.06.153
- Markovic J, Shortell C. Right gonadal vein transposition for the treatment of anterior nutcracker syndrome in a patient with left-sided inferior vena cava. J Vasc Surg Venous Lymphat Disord.2016 Jul;4(3):340-2. doi: 10.1016/j.jvsv.2015.09.002.
- Erben Y, Gloviczki P, Kalra M, Bjarnason H, Reed NR, Duncan AA, Oderich GS, Bower TC. Treatment of nutcracker syndrome with open and endovascular interventions. J Vasc Surg Venous Lymphat Disord. 2015 Oct;3(4):389-96. doi: 10.1016/j.jvsv.2015.04.003.
