Approach Considerations
After the diagnosis of chronic mesenteric ischemia (CMI) is made or confirmed with arteriography, patients should undergo open or endovascular revascularization because of the risk of continued weight loss, acute infarction, perforation, sepsis, and death. Because of the high rate of thrombosis, medical management as the sole therapy is warranted only when the risks of revascularization outweigh the benefits. Nitrate therapy may provide short-term relief but is not curative. Anticoagulation therapy with warfarin is indicated.
Because of the high rate of coronary artery disease (CAD) in these patients, consultation with a cardiologist is warranted to evaluate the potential risks associated with surgery. All CMI patients should be evaluated for cardiopulmonary and renal disease before surgery is considered.
Body mass index (BMI) needs to be included in the evaluation for revascularization in patients with CMI. BMI >25 is associated with poorer long-term survival after open revascularization. [11]
The prothrombin time (PT) and international normalized ratio (INR) should be monitored. Routine visceral duplex ultrasonography is recommended every 4-6 months. Obtaining a pretreatment base line is important.
In 2000, the American Gastroenterological Association released recommended algorithms for the diagnosis and management of mesenteric ischemia (see the image below). [27] However, these recommendations were formulated before the availability of improved data from multidetector computed tomography (CT) scanning, as a result of which CT now plays a larger role in the diagnosis of mesenteric ischemia.
Management of chronic mesenteric ischemia. Solid lines indicate accepted management plan; dashed lines indicate alternative management plan. MRA=magnetic resonance angiography; CT=computed tomography. Adapted from Gastroenterology. 2000 May; 118(5): 954-68.
Surgical Intervention
Indications for surgical management of chronic mesenteric ischemia (CMI) include the following [28] :
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Peritonitis
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Massive hemorrhage
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Recurrent fever or sepsis
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Continuation of symptoms beyond 2-3 weeks
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Chronic protein-losing colopathy
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Chronic segmental colitis with ulceration
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Symptomatic ischemic stricture
Management options for CMI are as follows:
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Angioplasty, with or without stent placement [29]
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Surgical revascularization
The choice between endovascular and open approaches to the treatment of CMI depends on multiple factors and should be tailored to the individual case. The two approaches have similar technical success and survival rates. [30, 31] Compared with open revascularization, stenting is associated with lower perioperative morbidity and mortality and shorter hospital stays. However, it is also associated with lower patency rates and higher recurrence rates, with increased need for repeat intervention.
A retrospective (2007-2014) analysis of National Inpatient Sample Database data from 4,150 patients with CMI who underwent endovascular or surgical (mesenteric bypass or endarterectomy) revascularization revealed endovascular therapy remained the primary revascularization modality. [32] Endovascular therapy was also associated with lower rates of in-hospital major adverse cardiac and cerebrovascular events (MACCE), composite in-hospital complications, lower costs, and shorter length of stay.
In recent meta-analysis of 100 observational studies revealed that open revascularization was associated with a significant increase in postoperative complications but nonsignificant increase in mortality rate at 30 days. At the same time, open surgery had better long-term results, lower risk of recurrence at 3-year cut-off. This observational meta-analysis concluded that the endovascular revascularization may offer early better outcomes but poor long-term results. [33]
Currently, it is common practice is to proceed with open revascularization if the patient has good life expectancy and fair nutritional status. Endovascular therapy is a good alternative in cases of poor nutritional status as a bridge to surgery or in cases with short life expectancy. Patient preference, age, comorbidities, and center expertise all play major roles in the decision. [5, 34, 35, 36, 37, 38]
The anatomy and the vessels affected also contribute to the treatment decision. In a study in which patients were treated with endovascular revascularization, clinical primary patency and primary patency were significantly higher for the superior mesenteric artery (SMA) group than for the celiac trunk group. [39]
Several studies have found a high rate of success with percutaneous stent revascularization for CMI, although repeated interventions may be necessary. [40, 41, 42] A nonrandomized study showed that covered stents were associated with less restenosis, recurrences, and repeat interventions than bare metal stents in patients undergoing primary interventions or repeat interventions for CMI. [39]
Surgical correction is accomplished by means of the following techniques:
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Transaortic endarterectomy of the celiac trunk or the superior mesenteric artery (SMA)
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Retrograde bypass from the external iliac artery
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Anterograde bypass, which provides the best orientation of the graft to the aorta
Mesenteric artery reimplantation has been performed but, because of its technical difficulty, is not widely recommended.
More recently, a retrospective study (1999-2016) of 24 patients who underwent a prosthetic bypass to the SMA reported success with using the infrarenal aorta as the donor site and infrarenal aortic grafts for revascularization of the SMA. [43] The investigators indicated that results from isolated bypasses to the SMA or those associated with an adjunctive bypass to the inferior mesenteric artery (IMA) are similar to those obtained with complete digestive artery revascularization using other donor sources.
Once a diagnostic arteriogram is obtained and surgery is deemed appropriate, intra-arterial papaverine is started to reduce the risk of arterial spasm. Any nutritional deficiencies (from the long period of malnutrition) or electrolyte imbalances should be corrected. In addition to arteriography, preoperative chest radiography and dipyridamole-thallium scanning may be considered. Bowel preparation is carried out the night before surgery, and the patient is on nil per os (NPO) status from midnight on.
After the procedure, because of the high rate of postoperative ileus, the patient is encouraged to ambulate as early as possible. Blood pressure is monitored to prevent hypotension, which can induce ischemia.
Complications
Because of the high prevalence of atherosclerosis, myocardial infarction (MI) is a common postoperative complication. The risk of MI can be reduced with the following steps:
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Identify patients at risk (eg, from correctable coronary artery disease) preoperatively
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Place a Swan-Ganz catheter perioperatively to monitor fluid status and cardiac function
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Inform the anesthesiologist when cross-clamping the celiac aorta, so that he or she can employ myocardial protective maneuvers and afterload reduction to maximize cardiac output
Another common complication is acute renal failure in the immediate postoperative period. This can be prevented with the following steps:
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Adequately hydrate the patient before and during the procedure
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Administer mannitol before cross-clamping the aorta
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Monitor blood urea nitrogen (BUN) and creatinine levels in the preoperative and postoperative periods
Other possible complications include bleeding, infection, bowel infarction, prolonged ileus, and graft infection.
Outcomes for open vs endovascular revascularization
Kougias et al compared the effectiveness of balloon angioplasty or endovascular stenting (48 patients, 58 vessels) with that of open revascularization (96 patients, 157 vessels) in the treatment of chronic mesenteric ischemia (CMI). [44] The investigators found that members of the endovascular group had a shorter hospital stay than patients in the open revascularization group did (3 vs 12 days; P< .03) and that the 30-day mortality, frequency of in-hospital complications, and 3-year cumulative survival rate were the same for the 2 groups.
At 3 years after the procedures, however, the rate of cumulative freedom from recurrent symptoms was higher in the open-revascularization group than in the endovascular group (66% vs 27%; P< .02). [44] The authors suggested that this was because the percentage of patients who underwent a 2-vessel procedure rather than a 1-vessel intervention was higher in the open group than in the endovascular group.
Another study compared the outcomes of patients with CMI who were treated with open mesenteric revascularization before (pre-endo) and after (post-endo) the preferential use of endovascular revascularization. [45] The results showed that patients in the post-endo group presented with higher rates of hypertension, hyperlipidemia, cardiac interventions, and dysrhythmias; higher comorbidity scores; and more extensive mesenteric arterial disease.
However, the pre-endo and post-endo groups had similar outcomes for operative mortality, morbidity, length of stay, and immediate symptom improvement. [45] At 5 years, primary patency rates, secondary patency rates, and recurrence-free survival rates were 82%, 86%, and 84% in the pre-endo group, respectively, and 81%, 82%, and 76% in the post-endo group, respectively.
Oderich et al studied 156 patients treated for mesenteric artery complications during angioplasty and stent replacement for CMI. [46] The investigators concluded that complications occurred in 7% of patients, who experienced higher mortality, higher morbidity, and longer hospital stays.
Diet and Activity
Because chronic mesenteric ischemia is a complication of diffuse atherosclerosis of the arterial tree, patients with this condition should maintain a low-fat diet, similar to that of patients with cardiac disease. Some patients report increased postprandial pain after eating large or fatty meals. Therefore, the diet should be appropriately altered to include small, multiple meals or low-fat meals.
As in patients with cardiac disease, regular exercise should be encouraged.
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Angiogram of patient with chronic mesenteric ischemia. Note diffuse occlusive disease.
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Radiograph showing tortuous, dilated, meandering artery.
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Narrowing of superior mesenteric artery.
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Chronic aortic occlusion (Leriche syndrome) with acute embolic occlusion of superior mesenteric artery.
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Gas in colon wall, typical of advanced ischemia.
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Meandering artery, sign of chronic mesenteric arterial ischemia.
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Management of chronic mesenteric ischemia. Solid lines indicate accepted management plan; dashed lines indicate alternative management plan. MRA=magnetic resonance angiography; CT=computed tomography. Adapted from Gastroenterology. 2000 May; 118(5): 954-68.
