Clinical and radiologic course of symptomatic spontaneous isolated dissection of the superior mesenteric artery treated with conservative management

Objective: To determine the clinical and radiological outcomes of patients with symptomatic spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) who were treated with conservative management. Methods: This retrospective study included 27 consecutive patients who were diagnosed with symptomatic SIDSMA and managed conservatively from April 2007 to April 2013. Twenty-six patients were treated using anticoagulation therapy, and one patient with chronic liver disease underwent observation only. For evaluation, patients were divided into two groups, those with a patent false lumen with both entry and re-entry (group I), and those with partial or complete thrombosis of the false lumen (group II). In general, the patients underwent follow-up computed tomography angiography (CTA) 1 week, 1 month, and 6 months after admission. Thereafter, they underwent annual CTAs. Results: There were five group I and 22 group II patients. During hospitalization, none of the patients needed additional endovascular or surgical intervention, and after conservative management, every patient was asymptomatic upon discharge. The mean duration of clinical follow-up was 27.3 months. There was no recurrent abdominal pain associated with SIDSMA, and no invasive procedures due to SIDSMA were needed. During a mean of 17.1 months of CTA followup in group I patients, serial CTAs found sustained patent false lumen and no angiographic changes in all patients. Among 22 group II patients, despite anticoagulation and symptomatic relief, CTA 1 week after admission revealed increased stenosis of the true lumen in 84.2% (16/19) of patients including six cases of progressive SMA occlusion. Five patients, including the three patients initially presenting with SMA occlusion, had no interval changes, and only one patient had improved compression of the true lumen. During a mean of 18.0 months of CTA follow-up in group II patients, serial CTAs revealed improvement in the occlusion or stenosis of the true lumen in 89% (16/18) of patients and progressive resolution of false lumen thrombosis in all patients. Aneurysmal dilatation greater than 2 cm was not detected in either group of patients during follow-up. Conclusions: During the acute stage of SIDSMA, we found a discrepancy between the clinical and angiographic findings. The therapeutic regimen should be based on clinical symptoms, and conservative management is feasible in most cases. SMA stenosis could not be an indication for invasive treatment, because stenosis of the true lumen has been seen to improve after the acute stage of dissection.