Chronic mesenteric ischemia is best treated in an open operation.
Chronic mesenteric ischemia is a rare disorder accounting for about 1 out of 100,000 admissions.1 Because of the rarity of this disease, diagnosis is often delayed. Patients are often evaluated for other gastrointestinal diseases and/or malignancies, which in turn contributes to significant delays in diagnosis. Additionally, there are no prospective, randomized trials on which to base decisions regarding treatment; and it is unlikely that such studies will ever be undertaken.
Chronic mesenteric ischemia develops when two or more of the mesenteric vessels (celiac, superior mesenteric [SMA], or inferior mesenteric [IMA]) become occluded or develop severe stenosis. In my experience, patients most often develop occlusion (as opposed to stenosis) of their mesenteric vessels. The atherosclerotic plaque responsible for the disease originates within the aorta and the stenosis/occlusion develops at the vessel origin.
Patients typically are older and have other manifestations of atherosclerotic disease including cardiac disease and peripheral vascular disease. Most patients have a history of smoking and thus may have poor pulmonary function and reserve. The presenting complaint is most often postprandial abdominal pain and patients learn that with food avoidance, the abdominal pain is averted which in turn leads to weight loss. The weight loss can be severe, mimicking the cachexia and malnutrition associated with advanced malignancies.
As a whole, these comorbidities would suggest that a more minimally invasive approach would be preferred. Yet, an open operation for chronic mesenteric ischemia should not be discarded as an initial operation.
Endovascular treatment of mesenteric ischemia is not without risk. As in all endovascular procedures there are complications associated with the access vessels. The orientation of the mesenteric vessels as they arise from the aorta often favors an approach from the left arm. The brachial artery is smaller than the femoral artery, and it is more difficult to apply pressure to the brachial artery to control the puncture site. This leads to a higher rate of access site complications including hemorrhage, pseudoaneurysm and thrombosis of the vessel. Bleeding or hematoma formation within the brachial neurovascular sheath can result in significant neurologic dysfunction of the arm and hand. There is risk of stroke, especially when the access vessel is the brachial artery. There are also complications directly related to the endovascular procedure.
Atheroembolism of plaque can result in occlusion of small mesenteric vessels and focal areas of bowel necrosis. Dissection of the mesenteric vessel can occur. Oderich has advocated for the use of a covered stent.2 A covered stent could cover proximal branches, and thus, in theory, the treatment itself could cause bowel ischemia or infarction. Many series that have compared open and endovascular surgery show no difference in early outcomes, but demonstrate early restenosis, decreased primary patency, and decreased assisted primary patency with endovascular treatment as compared with open operations.3-5
Another concern regarding the treatment of mesenteric ischemia is the status of the end organ, the bowel. Successful treatment of mesenteric ischemia cannot only assess the atherosclerotic lesion, but requires the surgeon to be cognizant of the condition of the bowel.
This concern is especially true for acute mesenteric ischemia,6 but the status of the bowel must also be kept in mind for chronic mesenteric ischemia. Unlike the lower extremity where the results of treatment are easily observed by inspection (color, evidence of atheroembolization), palpation (temperature, pulse), and physiologic testing (ABI), the bowel is not accessible. There are no highly accurate tests to determine if the patient has on-going bowel ischemia or has developed infarction. Should a complication occur, physical examination findings and laboratory changes often become apparent late in the course of the disease. As previously noted, these patients are often physiologically compromised and have little reserve and may not survive such complications. An open operation allows visualization of the bowel, before and after revascularization.
Traditional teaching for the surgical treatment of chronic mesenteric ischemia has emphasized that two mesenteric vessels, usually the celiac and SMA, should be revascularized.7,8 Various approaches to revascularization have been suggested including transaortic endarterectomy and an antegrade bifurcated bypass originating from the supraceliac aorta. These operations are effective in restoring flow to the mesenteric circulation, but both of these approaches involve aortic cross-clamping and are physiologically challenging for patients.
There are alternatives for open revascularization of the mesenteric vessels. The infrarenal aorta, iliac vessels, and even renal arteries can be, and have been used as the inflow source. It has been my experience that a bypass graft using an iliac artery (common or external) as the inflow source is well tolerated by patients. I have preferentially used either great saphenous vein or femoral-popliteal vein as the conduit. In many cases, the distal anastomosis is simply the SMA. However, both the celiac and SMA can be revascularized by creating a side-side anastomosis to the SMA and an end-side anastomosis to the common or proper hepatic artery. Such procedures have been durable, providing relief of symptoms and allowing patients to regain weight.9
In reality, I believe that an endovascular approach for the treatment of chronic mesenteric ischemia has a role. Vascular surgeons are uniquely positioned to carefully evaluate each patient and recommend what they feel is most appropriate. I tend to feel that an endovascular approach is less likely to be successful for patients with occluded vessels, especially those with a flush occlusion, and so will preferentially recommend an open operation for these patients. On the other hand, in my practice, I have used an endovascular approach for patients with severe stenosis, and as Dr. Harris states, know that a bypass is always an option should this be unsuccessful or ultimately fail.
Eric Endean, MD, is the director of the aortic center, Gordon L. Hyde Endowed Professor and Chair, and vascular surgery section head, vascular and endovascular surgery at UK HealthCare, University of Kentucky, Lexington. He had no relevant disclosures.
Presenting the case for endovascular intervention
Chronic mesenteric ischemia (CMI) is an uncommon, but lethal, problem when left untreated. Before the endovascular era, the only option was open revascularization, which is challenging in this chronically ill, malnourished population with diffuse, systemic, atherosclerotic disease. Morbidity and mortality was relatively high because of the comorbid conditions and chronically ill status of the patients. The first mesenteric bypass was performed in 1958 by Maynard and Shaw.1
Options for open repair include transaortic endarterectomy, antegrade bypass from the supraceliac aorta or distal thoracic aorta, or retrograde bypass from the iliac artery, all of which are major abdominal procedures. Endovascular interventions are now the most commonly performed procedures for CMI in the United States based on national studies.2
Endovascular intervention in the mesenteric circulation was first reported in 1980, with angioplasty alone.3 Stent use became more prevalent in the mid 1990’s. Endovascular revascularization can be performed with lower morbidity and mortality,4 and with local anesthesia alone or in combination with moderate sedation.
Technical success with endovascular interventions can be achieved in well over 90% of patients, and multiple vessels can be treated simultaneously from either a femoral or brachial approach. The primary concern with endovascular interventions has been long-term patency, with restenosis from intimal hyperplasia or thrombosis causing recurrent symptoms in up to 30%-50% at 3-5 years.5-7 However, these rates are based on use of bare metal stents, rather than covered stents. Recent studies8 suggest that stent grafts have markedly improved outcomes over bare metal stents for ostial lesions, decreasing recurrence. Oderich found that freedom from recurrence was 92% with stent grafts as compared with 53% for bare metal stents, with primary patency rates of 92%, at 3 years8, comparable to even the best open bypass results. Schoch first reported the use of covered stents in the mesenteric circulation, and found that no patients developed recurrent stenosis at 2 years.9 Other concerns with endovascular intervention include embolization and dissection, which have not been frequently reported.
Mortality from open surgery ranges from 5% to 15%, with morbidity of 30%-40%.4 Mortality from endovascular intervention is markedly lower, in the range of 3.56% vs. 7.23%.5 Long-term survival is not different between endovascular vs. open repair (69% vs. 65%),4 with the majority of deaths related to cardiac, pulmonary, or malignancy issues. Moghadamyeghaneh, in a review of the Nationwide Inpatient Sample database, found that open surgery was one of the major predictors for higher morbidity (odds ratio, 5.07) and mortality (OR, 5.13), despite the fact that endovascular patients were older (another risk factor for adverse outcomes) and had more comorbidities in this nonrandomized, real-world study.2
Further, if one considers cost as a metric for decision making, a Markov clinical decision model by Hogendoorn et al suggests an endovascular first approach is preferred, despite the presumed higher rate of recurrence expected with use of bare metal stents, rather than covered stents, utilized for this analysis.10 Clearly, the financial advantage would be even greater for endovascular with the lower rates of recurrence with covered stents more recently reported.
If a patient develops recurrent stenosis after endovascular intervention, open bypass may be considered as an alternate to repeat endovascular intervention, dependent on the nutritional status, life expectancy, and initial intervention undertaken. Alternately, patients who undergo open repair are not immune to restenosis, with a recurrence rate of 10%-20%.11,12 Oderich found that there was a 22% mortality in those treated with repeat open interventions, with a 47% complication rate. Endovascular interventions, however, had a significantly lower rate of complications, 16%, and mortality. For patients with recurrent disease after open revascularization for CMI, the endovascular approach should also be the preferred approach.
Any lesion which is anatomically suitable for endovascular repair should first have an attempt made via this approach, utilizing covered stents. While there is a role for open revascularization, endovascular interventions can be safely performed, with minimal morbidity and mortality, and good long-term patency, even in the sickest patients. Endovascular intervention should be the procedure of choice for chronic mesenteric ischemia and recurrent chronic mesenteric ischemia.
Linda Harris, MD, is professor of surgery; chief, division of vascular surgery; program director, vascular surgery residency & fellowship at the State University of New York at Buffalo; and an associate medical editor for Vascular Specialist. She had no relevant disclosures.