The shunt as temporary bypass -a modest proposal

The rise of cardiopulmonary bypass life support has also given a rise to the need to keep large, obstructive cannulas in femoral arteries. ECMO cannulas are often kept in for days, and it is not uncommon to discover limb ischemia and infarction relatively late. This can be avoided by placing a distal perfusion cannula to shunt blood to the leg early in the ECMO process. The ECMO cannulas have a convenient side port to send a little flow to a 6F sheath placed in the femoral or popliteal artery. This is an established technique (reference 1, sketch below), and it works despite the modest flows achieved because it does not take much to keep the leg alive. These patients are not walking, nor are they need to heal leg wounds, so just enough blood flow means something just a little more than what they get when the common femoral artery is completely occluded by the life support cannulas. What is fascinating to me is that these shunts can pptentially help to save limbs when used as temporary extracorporeal bypasses when definitive vascular surgical care is not immediately available.

brachial to femoral shunt sketch

 

When I was a medical student, I took on a research project after my first year where I had a Langendorff preparation of a rat heart (below).

langendorff prep in MRI
an isolated, perfused, beating rat heart placed in a superconducting magnet for NMR spectra acquisition 

My project was to take a rat heart and keep it alive, beating, and even working, through a perfusion apparatus and place this inside a superconductive magnet to obtain Phosphorus nuclear magnetic resonance spectra -intracellular metabolism data including concentration of ATP, intracellular pH, and ATP/ADP ratio. While the project was successful -I am quite proud to have been the only person at Columbia to have successfully acquired NMR-S data with living beating heart, I moved on to other interests and took away this concept: with oxygenated, glucose enriched, isoosmolar fluid perfused at arterial pressure, any organ can be kept alive, possibly indefinitely, including a brain which only recently others have found possible (reference 2) in reputable scientific circles, but the the Nature publishing Yalies were scooped by the Simpsons decades ago (below), and maybe Mary Shelley centuries before,

simpsons head

This is the simple idea. Revascularization is keeping the target vascular bed alive by delivering oxygenated blood. With a shunt, it could be little, it could be a lot, but it certainly is better than zero, and even a little can buy you time.

The breakthrough that I had was several years ago, a patient arrived from another hospital with an Impella pump which did not have a side port like an ECMO cannula. It is a large catheter that augments cardiac output and in the patient that I was asked to see this patient as their leg was cold and pulseless. Their cardiac output was very poor, and they were sustaining an augmented systolic pressure in the 90’s. There was no way to get this patient to the operating room for a revascularization of any sort. It did strike me that the patient had the misfortune of having catastrophic heart failure in the absence of significant athersclerosis and had normal brachial arteries. After discussing the ramifications with the ICU and family, I placed a brachial artery 5F cannula, and connected it to a 5F sheath I placed in the superficial femoral artery below the occlusive common femoral sheath (figure below). A doppler on the tubing connecting the two cannulas confirmed flow and the patient’s left hand maintained a pulsatile oximetry waveform. The leg pinked up and eventually there was a signal in the foot. This managed to perfuse the leg which did better than the patient who succumbed to multiorgan failure from heart failure. The leg did great.

Which leads me to these thoughts. Most hospitals are good at diagnosing large vessel occlusion via CTA. Most hospitals have doctors who can place arterial lines with ultrasound guidance. In the instance of aortoiliac occlusion or femoral occlusion from thromboemboliem, time is a critical limiting factor to limb salvage. Many hospitals do not have vascular surgeons. Many hospitals transfer these patients with a heparin drip but in the ischemic condition. Transfer arrangements may take hours. Why not ameliorate this situation by having an appropriate physician -an anesthesiologist, an intensivist, an EM physician, place an ultrasound guided radial or brachial arterial line, connect to arterial line tubing to a dorsalis pedis arterial line. Tape it all down on the patient after confirming flow (crude sketch below). This would be better than the three extra hours of ischemia the patient gets hit with on transfer. No one would transport a donor kidney without adequate perfusion and protection, but dying legs get transferred all the time with established warm ischemia. If done well, it might turn an emergency procedure into an urgent, semi-elective one. Have the vascular surgeon video conference in to confirm the absence of blood flow and appropriateness of temporary shunting.

radial to dp shunt
radial artery to dorsalis pedis artery shunt

If we are to live in  a world with less vascular surgeons, then the radius of survival has to be extended with use of technology and simple ideas such as this. Comments are welcome.

Reference
1. Foltan M, Philipp A, Göbölös L, Holzamer A,
Schneckenpointner R, Lehle K, Kornilov I, Schmid C, Lunz D. Quantitative assessment of peripheral limb perfusion using a modified distal arterial cannula in venoarterial ECMO settings. Perfusion. 2019 Mar 13:267659118816934. doi: 10.1177/0267659118816934.

2. Vrselja, Z., Daniele, S. G., Silbereis, J., Talpo, F., Morozov, Y. M., Sousa, A. M. Mario, S., Mihovil, P., Navjot, K., Zhuan, Z. W., Liu, Z., Alkawadri, R., Sinusas, A. J., Latham, S.R., Waxman, S. G., & Sestan, N. (2019). Restoration of brain circulation and cellular functions hours post-mortem. Nature, 568(7752), 336–343.

Arterial Restoration in CLTI with Remote Endarterectomy (EndoRE).

preop PVR

The patient is a man over 70 years of age who came to the hospital with severe pain of his right foot and leg with walking short distances and at night while recumbent. He had a history of hypertension, diabetes, and coronary artery disease, and several years ago had his left common iliac artery stented. On examination, he had no lesions of his foot, and his pulses were only palpable (barely) in the femoral arteries only. He did have strong monophasic signals in the anterior tibial arteries bilaterally.

Initial vascular lab testing showed only mildly depressed ankle brachial (above), with dampened waveforms consistent with inflow and femoropopliteal disease on the right. He underwent arteriography by our vascular medicine specialist and cardiologist Dr. Faisal Hasan, and it showed bilateral common iliac stenoses, a severely calcified and nearly occlusive plaque in the right common femoral artery, and a long segment occlusion in the superficial femoral artery with diffuse calcified plaque extending into the popliteal artery. There was diseased but patent 3 vessel tibial runoff.

aortogram

R SFA arteriogram

To Act As A Unit are the Cleveland Clinic’s words and it shows the Clinic’s roots as an US Army field hospital on the vasty fields of World War I France a little over a century ago, and we take it seriously. It may come as a surprise to some that a cardiologist referred me this patient after mutually deciding that the common femoral disease and the TASC D SFA occlusive disease, but we both decided that a surgical approach was the best one. The question then is how much more flow?

I ordered a CTA (CT angiogram) particularly for endarterectomies as I find it imperative to know the actual end point of plaque. Arteriography only hints at it, and while a 5mm lumen may look large and patent, it may be a channel in a 10mm wide plaque that when a stent terminates within it, breaks and becomes biologically active as intimal hyperplasia at best or embolizes at worst. CTA shown below revealed the plaque where contrast angio showed only the lumena of the vessels.

The 3D reconstruction function also allowed me to see and plan the operative approach and predict the lack of saphenous vein confirmed on duplex ultrasound.

For the students reading this, ischemic rest pain is often simpler to treat because it requires only a little more blood flow. There is a neurologic ischemia component that is not well studied, particularly in diabetics, as ischemia may result in anesthesia in someone who has underlying diabetic neuropathy, but that is not an indication for revascularization while rest pain is, and someone should investigate this. This little more blood flow in the form of treating inflow disease only may be sufficient in relieving rest pain while avoiding interventions on the superficial femoral, popliteal and tibial arteries which have limited longevity.

The common femoral artery on the other hand is the throttle of inflow and as a principle, inflow can be considered as the infrarenal aorta to profunda femoral artery, and repairing the common femoral necessitates an operation. There is no durable or laudable endovascular procedure for occlusive disease of the common femoral artery, a feature shared with the subclavian artery at the thoracic outlet and the celiac axis at the median arcuate ligament. All three are externally compressed by hard structures and revascularization must be ever mindful of the inguinal ligament, the thoracic outlet, and median arcuate ligament. The only exception to the “you must operate” rule of the CFA is calcified atherosclerotic disease in high risk individuals, and I make careful exception here with rotational atherectomy devices.

Claudication is another thing entirely. Claudication limits lifestyle and can be corrected by changing lifestyle -either with more exercise or limiting exercise. The thing is, when a patient has reached a certain age, that lifestyle may be walking slowly from chair to commode, and if that activity is limited, no amount of haranguing may be able to induce that person to embark on an ambitious exercise program. Sometimes, you have to be realistic about telling a frail old man to go for a 60 minute walk. But if that person has difficulty getting to the bathroom because of leg cramps, then either they have to get assistance or more bloodflow, and ironically, a little more blood flow represented by improving inflow, may not be enough.

That was what I was thinking when I was planning this operation. Improve the inflow with stents to the common iliacs and a right CFA endarterectomy, but use the opportunity of surgical exposure to extend the endarterectomy to the distal external iliac and through the entire SFA.

My fondness of remote endarterectomy is well known from my many blog posts on it (link). It is a modern update on a very old procedure -the ring endarterectomy, done since the middle of the last century when bypass grafts were unavailable. The occlusive plaque is removed, and an end-point reached and cut with a scissor like device (available from LeMaitre). It is the ultimate hybrid operation (below) requiring open and endovascular skills. I tell prospective trainees to judge training programs by how facile are the surgeons and how many are the procedures with and involving a hybrid approach, because any program can have few (getting fewer) old surgeons doing only open surgery and a lot of young surgeons doing only endovascular procedures, but a rare few will do a lot of hybrid procedures. endore-graphic.jpg

I chose to add femoral EndoRE. This would bring the extra blood flow needed to kickstart any walking program, barring cardiopulmonary limitations.

The patient was brought to our hybrid operating theatre and prepped from nipples to toes. The right common femoral artery was exposed for endarterectomy, and accessed then with a sheath along with a left femoral sheath for kissing balloon angioplasty and stenting of the common iliac artery stenoses (below).

preinterventionpost kissing stents

Afterword, the CFA was opened and endarterectomized, and the SFA was remote endarterectomized (below).

EndoRE setupEndoRE

The endpoint was chosen in the above knee popliteal artery to avoid having to stent the dissected end point plaque well into the popliteal artery. If I wanted to go all the way to the below knee popliteal artery, I would have to open it to manage the plaque and artery at the so-called trifurcation, typically with a patch angioplasty. The plaque came out in one piece (below):

EndoRE plaqueplaque in toto

The terminus of the plaque in the POP where it was cut has to be managed with a stent, unless you open and complete the endarterectomy and patch the artery. I was able to cross the dissection (no small feat) and plaque a stent. The artery was widely patent and even the small branches off the previously occluded SFA were now reopened.

Endpoint managementbefore and after endoRE

His pulse volume recording done after intervention reflects the improved flows (below).

PVR before and after

His rest pain resolved, but more gratifyingly, he has regained the confidence to walk and exercise, which he now does without limitation up to 45 minutes a day. In two month followup, we performed a duplex which showed his right SFA to be basically normal (below), including an intimal stripe and media. This is not an anomaly. When I took a punch out of restored artery to perform an anastomosis (from this case link), I sent it. Previously it had been an artery that was obstructed for nearly a decade, but after EndoRE, had become an elastic, compliant vessel. The pathology returned as “normal artery.”

postop duplex at 2 months

When these fail, they typically do so a random points on the endarterectomized vessel and on the stent. While stent grafting may have better outcomes with regard to restenosis, doing so covers collateral vessels and PTFE grafts behave poorly by embolizing while clotting off, and PTFE stent grafts are no different. Data from over a decade ago suggests that EndoRE of the SFA while inferior in patency to vein grafts, are equivalent to PTFE [reference 1] and superior to endovascular revascularization [reference 2] in terms of primary patency. When they occlude, they achieve a “soft landing” without the furious acute ischemia and embolization seen with PTFE bypasses.

I think these handful of cases I performed here in the UAE represent the first in the region. The main difference here is that the arteries tend to be smaller by about 20%, and in one instance, the smallest Vollmer ring was too large for the vessel in a case where I abandoned the SFA revascularization -the profunda and inflow revascularization proved sufficient in reversing rest pain. The intriguing property of endarterectomy is something that we all try to do with surgery but rarely achieve -a restoration to an earlier time. I believe this patient’s right femoral artery is now back to a youthful state.

References:

  1. Eur J Vasc Endovasc Surg 2009;37: 68-76

  2. J Vasc Surg 2012;56:1598-605.

Nutcracker Syndrome: The Renal Vein Transposition

sketch1496836916917.png

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.

00084038664_20170420_1.jpg

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.

venous duplex14.jpg

PREOP DUPLEX DOPPLER.png

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.

VENOGRAM.png
Arrow points to left ascending lumbar vein which is taking most of the reflux. It drains the left kidney across the midline via retroartic channels to the IVC
The films showed left renal vein compression by the superior mesenteric artery with outflow via the ascending lumbar vein, both supra and infrarenal tributaries. A midline exposure was performed and the retroperitoneum opened as in an transabdominal aortic exposure. The vena cava was exposed, and the left renal vein was mobilized by ligating and dividing its tributaries. A point 5cm below the tributary point was marked on the IVC, and this was the target for transposition.

IMG_0926.jpg

After heparinizing and clamping, the renal tributary was taken with a 5mm cuff –this would ensure proper length without narrowing the IVC.

sketch1496837342715.png

The vein was anastomosed and flow was excellent by pulse Doppler.

IMG_0927.jpg

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.

pre and post ctv comparison.png

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).

  1. Mesenteric ischemia
  2. Median arcuate ligament syndrome
  3. Nutcracker syndrome
  4. Neuromuscular
  5. Urolithiasis
  6. Inflammatory aortitis/arteritis
  7. Hypersplenism
  8. Portal hypertension
  9. Arterial aneurysm
  10. Infections
  11. Pelvic Congestion Syndrome
  12. Endometriosis
  13. 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:

  1. Varicose veins develop as an end stage process
  2. Reversal of flow or reflux is demonstrated, particularly into small tributary veins
  3. 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:

  1. Steep reverse Trendelenberg
  2. Hand injection 10mL half diluted contrast, gently as to not create false reflux
  3. Runs with catheter in left EIV, right EIV, left renal vein, right renal vein
    1. 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:

IMG_0925.jpg
Left renal vein at widest is 22mm, with expansion, possibly up to 28mm, but is relatively short. Do you see the SMA?
The variability in diameter and length of the Wallstent in the 22-24mm diameter range makes this a challenging deployment. Given that I would not be able to closely follow this young patient, I felt compelled to recommend a durable solution (ref 4).

References:

  1. 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.
  2. 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
  3. Markovic JShortell 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.
  4. 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.

When Hybrid Seems Better: Carotid Trauma As a Model For All Trauma

CXR.jpeg
Tracheal deviation due to iatrogenic carotid pseudoaneurysm

History

The patient is an 80 year old woman with lung cancer who was getting a port placed at her home institution. It was to be a left subclavian venous port, but when access was not gained, a left internal jugular venous port was attempted, but after the intitial stick and sheath placement, pulsatile bleeding was recognized and the sheath removed. Hemostasis was achieved with clips and the wound closed and a right internal jugular venous port was placed. The postprocedural CXR shown above showed tracheal deviation and numerous clips from the initial port placement attempt, and a CT scan with contrast (unavailable) showed a carotid pseudoaneurysm of 3cm projecting posteriorly behind the pharynx/esophagus. She was kept intubated and sedated, and transferred for management.
On examination, her vital signs were stable. She had 2cm of tracheal deviation and swelling was apparent at the base of the neck. While my trainees may be better versed at this than I at the particulars of this, my old general surgery trauma training kicked in, as she had a Zone I neck carotid injury, neck zones.pngwhich in my experience is highly morbid despite how stable the patient was. Point again to trainees, this is no different from someone having stabbed this patient with a knife at the base of the neck. My options were:

  1. Open repair
  2. Endovascular repair from femoral access
  3. Hybrid repair

Open Repair

Open repair is the approach of choice for zone 2 injuries because aerodigestive tract injuries can also be addressed and the exposure is straightforward. For Zone 1 injury, the exposure is potentially possible from a neck exposure, but in my experience, jumping into these without prepping for a sternotomy puts you into a situation without a plan B. The exposure of the carotid artery at this level becomes challenging with hemorrage from the artery once the compression from the hematoma or pseudoaneurysm is released. A sternotomy in this elderly woman, while not optimal, may be necessary if open control is required, but the best plan is to avoid this.

Endovascular Options

This should be a straightforward repair from an endovascular approach, even with the larger sheath required for the covered stents. A purely endovascular approach is problematic for two reasons. One, cerebral protection devices are built for bare carotid stents and not peripheral stent grafts, but this is not prohibitive -it should be fine. Without a planned drainage, the hematoma would be left behind which could cause prolonged intubation and problems with swallowing -both an issue for an elderly patient battling lung cancer. Endovascular access could provide proximal control for an open attempt from above, but instrumenting from the arch in an 80 year old has a known 0.5-1% stroke rate.

Hybrid Repair

A hybrid open approach with exposure at the carotid bifurcation offers several advantages. With control of the internal carotid artery, cerebral protection is assured while the carotid artery is manipulated. At the end of the procedure, the internal carotid can be backbled through the access site with the common carotid artery clamped. The hematoma could be avoided until the stent graft is deployed. An unprotected maniplation in the arch can be avoided. Once the stent graft is deployed, drainage of the hematoma can be performed.

carotid control

This required setting up a table off the patient’s left that allowed the wire to lie flat to be manipulated by my right hand. The carotid bifurcation was accessed through a small oblique skin line incision and the common, internal, and external carotid arteries, which were relatively atherosclerosis free, were controlled with vessel loops. The patient was heparinized. The internal carotid was occluded with the loop, and the common carotid below the bifurcation was accessed and an 8F sheath with a marker tip inserted over wire. Arteriography showed the injury and pseudoaneurysm.

prestent angiography.png

The location of the injury based on CT and on this angio would have baited a younger me into directly exposing it, but experience has taught me that which occasionally you can get away with it, the downsides -massive hemorrhage, stroke, need for sternotomy, just aren’t worth it. The sheath was brought across the injury and a Viabahn stent graft was deployed across the injury.

post deployment angiography.png

The hemorrhage was controlled and the hematoma was then exposed and drained -the cavity was relatively small and accepted the tip of a Yankauer suction easily. A Jackson-Pratt drain was placed. The access site was repaired after flushing and retrograde venting as described.

She recovered rapidly after extubation postop. She was able to breath and swallow without difficulty and had suffered neither stroke nor cranial nerve injury. The drain was removed on postop day 2.

The patient recently returned for a 6 month followup. Duplex showed wide patency of her stent.

7 months post op.png

More gratifyingly, her port was removed as her cancer was controlled with an oral regimen.

Discussion

Let me start with my bias that all penetrating trauma should be approached in a hybrid endovascular OR. It is a natural setting for trauma and this case illustrates that. In a hybrid operating room, central aortic and venous injuries can be controlled endovascularly while open repair, including salvage packing, can be done. Excess morbidity of central vascular exposures can be avoided. Temporary IVC filters can be placed if indicated (becoming rarer and rarer). Cardiopulmonary bypass can be started.

In this patient, hybrid therapy brought the best of both techniques and avoided many of the pitfalls of the purely open or endovascular approach. For stable zone I penetrating injuries of the neck, it is clear that this is a reasonable approach.

Chronic IVC occlusion causing venous claudication and ulcers requires treatment

intervention79
The patient is a gentleman from out of state who had called about problems he was having with walking and with leg ulcers that wouldn’t heal. He is in his seventies and has a pacemaker for an arrhythmia for which he was on Xarelto. He also had type II diabetes. He had bilateral lower extremity deep venous thromboses 6 years prior requiring IVC filter placement. The filter occluded, and it resulted in sudden sharp and debilitating pain in both legs with walking short distances -some days only 50 paces.He described it as an unbearable pain in calves and thighs that felt like his legs were going to burst. He also had ulcers on his legs that would heal with ministration but soon recur. This was all despite being quite active, with regular workouts, and being fit. He was compliant with compression. He sent a CT scan done last year (below).

Annotated R iliocaval Centerline Preop CT.jpg
Right iliocaval centerline projection

It showed an Optease retrievable vena cava filter that was occluded and the iliac systems bilaterally (right above and left below) were chronically occluded with patent vena cava above and femoral confluences bilaterally below.

Annotated L iliocaval Centerline Preop CT.jpg
Left iliocaval system showing chronic occlusion on centerline projection

He had no hypercoagulability nor ongoing recent DVT’s. I thought there was a good chance that we would be able to recanalize the occluded iliocaval segment and he flew in for a consultation, and he was pencilled into the schedule ahead of his visit.

Examination revealed a fit and trim man in his 70’s in no apparent distress. He had bilateral leg edema that was moderate with small superficial and tender ulcers of the right posterior distal calf. Pulses were normal. He was taken to our hybrid suite and venography from femoral vein access in the proximal thigh in the supine position revealed his right and left iliac venous systems to be occluded (below figures).

right initial venogram
Right injection from femoral sheath showing occluded iliac vein with collaterals
left initial venogram.png
Left injection

Wire access into the iliac systems was performed with Glidewire and Glidecatheter periodic venography to confirm that I had not exited the vein. Unlike the arterial system, extravasation from being extravenous does not have the consequence of bleeding, hematoma development, and pseudoaneurysm formation because of the low pressure, but it can be a long procedure and uncomfortable as well so these are done under general anesthesia.

intervention fig 1.png
Advancing wire and sheath into iliac vein, crossing filter resulted in extravasation of contrast

Once position confirmed to be in the iliac vein, the vein was dilated to allow for greater ease of movement. In the case of the uncrossable filter, I switched to access from above via a right internal jugular vein access.

intervention fig 2.png
Dilating vein (left) for greater mobility, and crossing from above (R. IJV access)

Once the wire crossed into the iliac vein from above, it was captured and brought out. While ballooning by itself is inadequate for revascularization, it greatly eases wire capture and on the right, it was done simply by driving the wire from above into the sheath. Wire capture wins access across the iliocaval and IVC filter occlusion from below.

intervention fig 3.png
Wire passage across IVC filter into right and left systems

Once wire access is done, ballooning across the filter is done from both sides. A large sheath is them delivered across the IVC filter. Finally, a Palmaz stent mounted on a large balloon is delivered and deployed. I chose to do this from the right access, and retracted the wire on the left -something done with some trepidation because of the great difficulty gaining this access, but with with prior balloon dilatation, reaccess is made easier. Also, plan B would be reaccess from above.

intervention fig 4.png
After balloon dilatation of occlusion typically to 8mm from both sides, a sheath placed and Palmaz stent deployed across filter on a large 24mm balloon

When this is accomplished, the left sided wire is reaccessed across this stent. This is the venous side analogue to gate access in EVAR (below).

intervention fig 5.png
Reaccess of the left iliac venous wire across Palmaz stent

Once this is done, the iliac veins are dilated to 14mm from the IVC to the common femoral arteries. large 18mm Wall stents are deployed in a kissing fashion from the caval stent into both iliac systems and dilated to 18mm.

intervention fig 6.png
Predilatation of iliac venous systems with ever larger balloons, deployement of bilateral 18mm Wall Stents

After deployment, the Wall Stents are ballooned to 18mm. These stents were extended into the common femoral artery with 14mm nitinol stents.

intervention fig 7.png
Ballooning 18 mm Wall Stents with 18mm Atlas balloons, then extending to CFA with nitinol stents of 14mm

Completion venography suggested successful iliocaval recanalization and revascularization but these procedures are not done without a final intravascular ultrasound (IVUS).

Looks done, but needed final intervention after IVUS.

Intravascular ultrasound revealed incomplete expansion of the right common femoral stent. This was treated with another stent and ballooning with the result on the right.

Stent compression on IVUS treated with second stent

Venography alone is insufficient in determining patency. As illustrated, IVUS ensures a durable outcome.

The leg ulcer was treated with an Unna’s boot. A word about the venerable Unna’s boot –it works. The dressing dries and compresses while the Zinc Oxide prevents bacterial growth. It is interesting that the dressing is so infrequently used nowadays but not so when you consider that it isn’t reimbursed. And patients generally hate it.

This revascularization has an excellent chance at working as the patient has no hypercoagulability and had a patent common femoral confluence bilaterally. As I had mentioned in a prior post, the idea in venous revascularization is connecting confluences that serve as inflow and outflow.

Confluences

This will require followup, consisting of duplex, and it is advantageous that he is anticoagulated for his arrhythmia. It is becoming more apparent that those languishing with chronic venous insufficiency and its complications need the IVC and iliac veins interrogated with a duplex. When an obstruction is found, they should be treated with these techniques as a first line therapy.

 

Complex femoral pseudoaneurysm with arteriovenous fistula and large hematoma treated with novel hybrid therapy

wide avf and pseudo

The patient is a middle aged man who after an interventional procedure was referred to my clinic with an expanding hematoma due to a pseudoaneurysm complicated by an arteriovenous fistula. He was a week out from his procedure and had grown a hematoma roughly the size of a hard boiled egg in his left groin which caused him pain. A duplex scan showed a pseudoaneurysm (below) with fistula flow.

preduplex12

On examination, he had this well circumscribed indurated hematoma of hard boiled egg size with tenderness. There was a bruit on auscultation. Duplex showed a small chamber of flow adjacent to the proximal superficial femoral artery emptying into the femoral vein. Doppler in the common femoral vein showed relatively high fistula flow, and this is reported to be associated with failure of thrombin injection. CTA (top) demonstrated flow of contrast from femoral artery to vein through a pseudoaneurysm chamber that laid between. Angulation to an axial orientation showed this better (below).

axial AVF
Contrast flows from femoral artery (right) to the fistula chamber, then into the femoral vein.

axial CTA avf pseudo
Axial MPR
Operation was planned, but in the days leading up to the operation, I had a thought -the primary reason why ultrasound guided thrombin injection would fail is the AVF. It would be simple to fluoroscopically guide an angioplasty balloon on the arterial side to occlude the fistula inflow. The next step would be to get access to the pseudoaneurysm with a needle under ultrasound guidance, confirm location with a contrast injection. Once confirmed, the balloon is inflated and a small volume of thrombin would be injected. I discussed this with the patient in detail and he was enthusiastic about trying this before proceeding with an open repair.

 

pseudoaneurysm avf procedure sketch
Schematic of procedure
The procedure went as planned. Ultrasound guided access is aided with dual live display of B-mode and color flow (below)

Arteriography showed much of the contrast from injection of the pseudoaneurysm to preferentially go to the artery which made me worry less about creating a DVT/PE. With balloon inflated (below), thrombin was injected and balloon inflation held for about 30 seconds.

angio procedure31

There was resolution of flow in the pseudoaneurysm and in the fistula. Before and after duplexes are composited below.

prepost pseudo chamber

Repeat duplex on the following day showed resolution of the pseudoaneurysm and arteriovenous fistula.

In the days before ultrasound guided thrombin injection of pseudoaneurysms, open surgical repair of these was fraught with complications. First, these patients typically had cardiac disease. Second, they were usually anticoagulated often with multiple agents. And finally, they were  many times obese, making not only the operation fraught with complexity, but the ultimate wound healing a delicate and rare phenomena. Even now, we get emergency repairs when access hemostasis fails, and these patients are typically high risk. With hematoma evacuation, inflammation, lymph leaks, and infections may follow; the patient was correct in his enthusiasm for agreeing to proceed with a minimally invasive effort.

As to the techniques, they are all well established in the vascular surgeon’s toolbox. Ultrasound guided access of the pseudoaneursm should be obtained before arterial occlusion. This was  facilitated by general anesthesia which kept the patient from moving. Having access to excellent ultrasound and angiographic imaging made this possible. The patient felt much better and was discharged home the next day after his confirmatory duplex.