A basic recipe for treating complicated aortic dissection
A basic recipe for treating complicated aortic dissection
It was only last month when I came across a post of an aortic aneurysm in a difficult spot (link) and I couldn’t help chiming in some comments. Reading it now, I sound insufferable, because I wrote,
“Depends on etiology and patient risk stratification. Also assuming aneurysm goes to level of SMA and right renal artery origins and involves side opposite celiac. Options depending on resources of your institute: 1.Open repair with cannulation for left heart bypass and/or circulatory arrest 2.Open debranching of common hepatic, SMA, R. Renal from infrarenal inflow and then TEVAR 3.FEVAR from custom graft from manufacturer on protocol 4.Parallel grafting to CA, SMA, R. RA with TEVAR 5.Surgeon modified FEVAR 6.Open Repair We would have a multidisciplinary huddle around this patient -Vascular, Cardiac Surgery, Cardiology, Anesthesia, and ID (if needed) to help choose. Be ready to refer to a center with more resources -including prepping patient for transfer and imaging -including uploading images to the cloud for transfer with patient’s permission. More info please”
More Info Please, Indeed
The post I commented on was of a saccular aneurysm in the transdiagphragmatic segment of aorta. Ironically, only a few weeks later, I got called from hospital transfer center about a patient with a leaking aortic aneurysm, a type V thoracoabdominal aortic aneurysm as it turned out, from an outside hospital, needing urgent attention, and we accepted in transfer based on the conversation I had with the tranferring physician. And that was the problem -usually in taking these inter-hospital transfers, you have to pray that the precious CT scans come along with the patient burned correctly onto a CD-ROM. You can buy and watch a movie in 4K resolution over the internet -about 4 gigabytes, but a patient’s CT scan which is about 200 megabytes -because of various self imposed limits, overly restrictive interpretations of laws, and lack of computer skills, these life saving images get transferred on CD in 2019. That last time I purchased a CD for anything was over 15 years ago.
An Interested Party
The technical solution –to use the internet to transfer critical life saving information between hospitals – came about when our IT folks took an interest in my quarterly complaint email about using the newfangled internet for sharing files. After mulling various solutions ranging from setting up a server to using commercial cloud solutoins, we came upon the compromise of using our internal cloud with an invitation sent to the outside hospital. I would send this invitation to upload the DICOM folder of the CD-ROM to an outisde email address. It was simple and as yet untried until this night. “Would the patient agree to have his CT scan information transmitted to us electronically?” I asked the other physician. He assured me that the patient was in agreement.
It Takes Two to Tango
Of course, being able to transfer these pictures requires a willing partner on the other side, and the referring physician made it clear he did not have the technical expertise to do so. It took a bit of social engineering to think about who would have that ability. Basically, aside from myself, who spend all their time in dark rooms in the hospital in front of giant computer monitors? The radiologists! I got through to the radiologist who had interpreted the report and explained the simple thing I needed. Gratefully, he agreed, and I sent him a link to our cloud server. I explained to him, “When you receive this, clicking the link opens a browser window and then you open the CD-ROM and find the DICOM folder and drag and drop it on the browser window.” The 200-500 megabytes of data then get sent in electronic form, as it was meant to in 2019.
The Internet Saves a Life
The brutal truth is that in locking down a computer system, many hospitals make it impossible to even load an outside CD-ROM, creating many self imposed barriers to care. Thankfully, at CCAD, we were able to work together to find a secure solution. With the CTA on our servers, I was able to review the study within 15 minutes of accepting the patient, and arrange for the right team to be assembled, and confirm that we had the right material (stent grafts) for treating the patient. When the patient arrived, OR was ready to go, saving hours of time that normally would have been required if the CT scan had to be reviewed from the CD-ROM that came with the patient. Sometimes, the CD-ROM does not come, and in a critical situation, the CTA has to be repeated with some risk to the patient for complications of the contrast and radiation.
What to Do
The patient had a 8cm sphere shaped aneurysm arising in the transdiagphragmatic aorta, leaking into the right pleural cavity.
The patient was otherwise a healthy middle aged man with risk factors of smoking and hypertension. The centerline reconstructions showed the thoracic aorta above the aneurysm to be around 20mm in diameter and same below, with the celiac axis and superior mesenteric artery in the potential seal zone of a stent graft. The only plaque seen was around the level of the renal arteries and was focal and calcified. Looking at the list I had made as a comment to the Linked-In post, I realized that I really only had one viable option.
Open repair, usually the most expeditious option, was made challenging by the right hemothorax, making a left thoracotomy hazardous if the lung had to be deflated. Cardiopulmonary bypass would have to be arranged for, and that adds a metabolic hit that greatly raises the stakes. Of the endovascular solutions, the only viable option was TEVAR to exclude the rupture and debranching of the celiac axis and superior mesenteric artery. To those who would advocate for parallel grafts, there was no room in the normal 20mm diameter aorta. And branch systems for rupture are some time in the future. Also, the patient was becoming hypotensive. So the planned operation was first TEVAR to stop the bleeding, and then open surgical debranching. A hybrid repair.
The smallest stent graft we have is a 21mm graft, but it would not be suitable for this aorta. In practice, the normal aorta is quite elastic and will dilate much more than what is captured on a CTA. The next size we have is 28mm graft and I chose this to exclude the rupture, which was done percutaneously.
As seen below, the graft excluded the celiac and SMA. Late in the phase of the final aortogram (second panel) there was an endoleak that persisteed despite multiple ballooning. The timing suggested the intercostals and phrenic vessels contributed to a type II endoleak, but it was concerning.
The bypasses were sent from the infrarenal aorta to the common hepatic artery and the SMA close to its origin, and the origins of the celiac axis and SMA were clipped. The bypasses were then done with a 10x8mm bifurcate Dacron graft originally for axillofemoral bypassing. It had spiral rings which I removed at the anastomosis and this resulted in a kink at the closer bypass. Usually, I loop this for iliomesenteric bypass but there was not enough distance from the infrarenal aorta. I have to add a little trick I modified from my pediatric surgery experience as a resident -a Heinecke-Mikulwicz graftoplasty:
This worked to relieve the kink as evidenced on the aortogram above. After closing the laparotomy, I placed a chest tube in the right chest. The patient had a course prolonged by a classic systemic inflammatory response syndrome, with fevers, chills, and leukocytosis. He bled for a while but stopped with correction of his coagulopathy. All blood cultures were negative, but a CT scan was performed out of concern for the endoleak, and the possibility of continued bleeding.
No endoleak was detected as the sac was fully thrombosed. There was a consolidation of the blood in the right chest, but it resolved with fibrinolytic therapy.
This case illustrates several points I have been making on this blog.
I was invited by Dr. Martin Maresch to speak on complicated type B aortic dissections. Should be an exciting day.
From Dr. Dmitirios Virvilis, formerly my trainee, now my colleague, who had this interesting case of end-stage iatrogenic pseudoaneurysm.
85-year-old gentleman with history of atrial fibrillation on anticoagulation, mechanical valve on Coumadin presented to our emergency department with significant hemorrhaging from the right groin (figure above). The patient had a coronary angiogram 2 months earlier done elsewhere complicated by a pseudoaneurysm which was managed with ultrasound guided thrombin injection that was not successful. Patient was sent to a vascular surgeon at another facility and the decision was made to intervene with the placement of a covered stent on the common femoral artery (possibly due to high patient risk?) compromising the junction of the SFA and profunda artery. The patient developed a large hematoma following placement of the covered stent and was managed solely with antibiotics for over a month prior to presentation.
On physical examination, the patient was septic, lethargic with grossly infected groin (image above). A CT scan with contrast was performed which showed active extravasation with stranding around the femoral vessels (below).
The patient was taken emergently into the operating room. Due to the extent of the infection under the inguinal ligament I obtained proximal control by performing a retroperitoneal flank incision. The iliac vessels were controlled and then I proceed with exploration of the hematoma. The junction of the superficial femoral artery and the profunda artery was separated and the common femoral artery was liquefied. There was only a very thin posterior layer of the common femoral artery and the cover stent was floating in the hematoma. The wound was thoroughly debrided. The distal external iliac artery was transected and the stent was removed. The junction of the superficial femoral artery and profunda artery were separated. A Rifampin soaked graft was used (picture below), which was an 8mm gelatin impregnated Dacron graft soaked in Rifampin (600mg in 200mL of saline) for 20 minutes.
The graft was anastomosed to the common iliac artery to fully exclude the external iliac artery which was debrided and ligated. The profunda artery was reimplanted on the side of the graft in an end-to-side fashion. After the wound was thoroughly irrigated and the graft was covered . The muscle flap was created in the usual fashion with lateral mobilization preserving the medial vascular pedicle. The wound was partially approximated and the top of the wound was left open for an application of wound VAC (below). The fact that I am practicing in a remote area has made me to be more efficient and incorporate in my practice many procedures picked up through training that fall under general surgery, plastic surgery, and advanced vascular surgery.
Patient remained hemodynamically stable and recovered in the ICU for 48 hours. After hospital course of approximately 5 days was finally discharged to rehabilitation center. Patient was seen 1 month and 2 months after the first operation and has had completely healed incision (below). There is a strong femoral pulse on the right groin with multiphasic pedal signals. Patient has completed 8 weeks of IV antibiotics. I am planning to perform a CT angio with runoff in the next few months in order to evaluate my distal anastomosis because I am concerned about the Pseudomonas that grew from the OR cultures.
From technical standpoint there is 2 things that I would like to address:
#1: The textbook answer would be to perform a bypass with a native conduit with deep femoral vein or great saphenous vein, but this is difficult to perform efficiently solo. I do not have CryoVein on the shelf and the cost of such a conduit is prohibitive in my institution. And extra-anatomic bypass also on the lateral approach, an obturator bypass, adds time and complexity especially with the separation of profunda and superficialis.
#2 Next time I will have to perform a bypass like that I will probably perform the bypass first to the profunda artery and then reimplant the SFA which is more mobile.
Discussion by W. Michael Park, MD
I have to congratulate Dr. Virvilis on this nice outcome. I agree on remaining vigilant for late re-emergence of infection, but it is very unlikely to occur as time passes without signs and symptoms. I have three things to add. First is that Rifampin soaked graft is effective in revascularizing within a decontaminated field while sewing to uninfected artery. Taking the graft to the common iliac bifurcation which was exposed to gain proximal control was wise as anastomoses to the external iliac under the inguinal ligament are challenging and there was an unknown degree of infection here. Second is the sartorius muscle flap must be in the armamentarium of every vascular surgeon and is an easy jumpoff point to learning gracilis and rectus femoris flaps as well. The lateral mobilization and medial rotation is done preserving the medial arteries that feed the graft -dividing too many of these to mobilize the flap kills the flap. The flap delivers the immune cells and vascularity to clear the remnants of infection and forms a better granulation source bed than debrided, infected wound.
Finally, Dr. Virvilis did reach out to me from around the planet (I work in Abu Dhabi, he in Mississippi) for a run through of his plan. I cannot tell you how valuable this is to be able to bounce ideas off of someone you trust. When I graduated from my fellowship, Tom Bower put his hand on my shoulder and said, “Do not hesitate to call me if you have a difficult situation.” I have since grown a long short-list of mentors, friends, and partners on speed dial. It taps me into cumulative millennia of surgeon-years of experience. With social media and increasing acceptance of its use to share ideas, there is absolutely no reason to work in isolation.
This was presented at Dia De La Patología Aortíca Marbella organized by Dr. Fernando Gallardo.
Here is the link.
I recently had to remove a stent graft for infection and got to thinking about how the number of people who could comfortably and confidently manage that has thinned out in the world through the unintended consequence of the medical device market place. In every surgical specialty over the past twenty years, many open procedures were replaced with a minimally invasive option which generally involved adoption of new technology and large costs to the hospital. These newer procedures were touted as easier on the patient while being easier to perform for the average physician than the open procedure that they were replacing. That was the other selling point -that one could do several of these operations in the time it took one open procedure. In most cases, they were at best almost as good as the open procedure but at higher cost.
In the marketplace, minimally invasive always wins. In many specialties it became untenable to practice without marketing these “advanced minimally invasive” skills. Hence, the wide adoption of robotics in urology outside major academic centers -during those years of rapid adoption the surgeons would get flown to a course, work on an animal model, then for their first case a proctor would be flown out and voila -a minimally invasive specialist is born. The problem comes when learning these skills displaces the learning of traditional open surgical skills. In general surgery, it is not uncommon to hear of residents graduating without having ever having done an open cholecystectomy. It is also the case that many vascular trainees graduate with but a few if any open aortic cases. What happens when minimally invasive options run out? Who will do my carotid endarterectomy or open AAA repair?
The first case is an elderly man with an enlarging AAA sac despite having had EVAR about seven years prior. No endoleak was demonstrated but the proximal seal was short on CT. Also, it was a first generation graft which is prone to “peek a boo” endoleaks from graft junctions and stent anchoring sutures. On that last point, I use the analogy of a patio umbrella -after seven seasons, they can leak where cloth is sewn to the metal struts. It is very hard to demonstrate leak of this kind on CTA or duplex ultrasound because they are small. The patient had his EVAR because he was considered high risk for open repair at the time of his operation -moderate COPD, mild cardiac dysfunction. His sac had enlarged to over 6cm in a short time, and therefore open conversion was undertaken. No clinical signs of infection were present. A retroperitoneal approach was undertaken. After clamps were positioned, the sac was opened.
The picture does not show it, but a leak from the posterior proximal seal zone was seen with clamp off. The clamp was reapplied and the graft transected flush to the aortic neck. A bifurcated graft was sewn to this neck incorporating the main body stent graft and aortic neck in a generous running suture. The left iliac limb came out well and the new graft limb sewn to the iliac orifice, the right iliac limb was harder to clamp and therefore I clamped the stent graft and sewed the open graft to the stent graft.
The patient recovered well and went home within the week. He was relieved at no longer needing annual CT scans.
Who needs annual CT scans? Patients with metastatic cancer in remission.
The second patient was an older man referred for enlarging AAA sac without visible endoleak. The aneurysm had grown over 7cm and was causing discomfort with bending forward. He too had been deemed high risk for open repair prior to his EVAR. If he had had an early generation Excluder graft, the possibility of ultrafiltration would be more likely and relining the graft would be reasonable (link). This was again a cloth and metal stent graft which can develop intermittent bleeding from graft to stent sutures, and I don’t think relining will help.
The patient was taken for open repair (above), and on opening the AAA sac, bleeding could be seen coming from the flow divider. It stopped with pressure, but I replaced the graft in a limited fashion from the neck to the iliac limbs as in the first case. This patient did very well and was discharged home under a week.
The third patient was another fellow referred from outside who had an EVAR for a very short and angulated neck, and a secondary procedure with an aortic extension in an attempt to seal the leak had been done. This failed to seal the type Ia leak. This patient too was deemed too high risk for open surgery of what was basically a juxtarenal AAA with very tortuous anatomy.
The patient was taken for open repair, and the stent grafts slid out easily (below).
A tube graft was sewn to the short aortic neck and distally anastomosed to the main body of the stent graft -with pledgets because of the thin PTFE graft material in this particular graft. This patient did well and went home within a week.
All three cases are patients who were deemed originally too high risk for open repair, who underwent EVAR, then underwent explantation of their failing stent graft. Only one involved a patient whose graft was placed off the IFU (short angled neck), but the rationale was that he was too high risk.
What is high risk? In non-ruptured, non-infected explantation of failing stent graft, the mortality is 3% (ref 2) from an earlier series from Cleveland Clinic. With stent graft infection, the 30-day mortality of surgical management from a multi-institutional series was 11% (ref 3) when there was no rupture. From a Mayo Clinic series, stent graft resection for infection came with a 4% 30-day mortality (ref 4). These were nominally all high risk patients at the time of the original EVAR.
Real world risk is a range at the intersection of patient risk and the expertise of the operating room, critical care, and hospital floor teams. The constant factor is the surgeon.
Endografts for AAA disease (EVAR, endovascular aortic aneurysm repair), makes simple work of a traditionally complex operation, the open aortic aneurysm repair. The issue has been the cost and risks of long term followup as well as endograft failure and aneurysm rupture. The Instructions For Use on these devices recommend a preop, a followup 1 month, 6 month, and 12 month CTA (with contrast) and annual followup with CTA for life. These devices were meant to treat high risk patients but high risk patients with limited life spans do not benefit from EVAR (ref 1, EVAR-2 Trial). These have lead the NHS in the UK to propose that EVAR has no role in the elective repair of abdominal aortic aneurysms in their draft proposal for the NICE guidelines for management of AAA (link). While this is a critical discussion, it is a discussion that is coming at least ten years too late. A generation of surgeons have been brought up with endovascular repair, and to suddenly announce that they must become DeBakey’s, Wiley’s, Imperato’s, and Rutherford’s is wishful thinking at best or wilful rationing of services at worst.
In 2006, Guidant pacemakers were recalled because of a 1000 cases of possible capacitor failure out of 28,000 implants for a failure rate of 3.7% -there were 2 deaths for a fatality rate of 0.00007%. EVAR-1 Trial’s 8 year result (ref 5) reported 16 aneurysm related deaths out of 339 patients (1.3%) in the EVAR group compared to 3 aneurysm related deaths out of 333 patients (0.2%) in the OPEN group.
Academic medical centers, behemoths though they are, serve a critical function in that they are critical repositories of human capital. The elders of vascular surgery, that first and second generation of surgeons who trained and received board certification, are still there and serving a vital role in preserving open aortic surgery. My generation -the ones who trained in both open and endovascular, are still here, but market forces have pushed many of my colleagues into becoming pure endovascularists. The younger generation recognizes this and last year, I sat in on an open surgical technique course at the ESVS meeting in Lyons organized by Dr. Fernando Gallardo and colleagues. It was fully attended and wonderfully proctored by master surgeons. This is of critical importance and not a trivial matter. As in the 2000’s when endovascular training was offered as a postgraduate fellowship in centers of excellence, there is no doubt in my mind that today, exovascular fellowships need to be considered and planned and that current training must reinvigorate and reincorporate their open surgical components.
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.