Superior mesenteric artery aneurysms: Is presence an indication for intervention?

Introduction: Although rare, superior mesenteric artery (SMA) aneurysms have a definite rupture risk. Past reports have suggested that this risk is low, yet most investigators recommend repair in selected patients. We reviewed our experience with 21 patients to try to determine when intervention was indicated. Methods: A retrospective review of the medical records of all patients with SMA aneurysms at our institutions from January 1980 through December 1998 was undertaken. Only patients with true aneurysms of the SMA were included. Results: Twenty-one patients with true SMA aneurysms were identified and included 14 males (67%) and seven females (33%). This represents a 6.9% incidence rate of all visceral aneurysms seen at our institutions. Eight patients (38%) had rupture at presentation, including seven of the 14 males (50%). In contrast to previous reports, only one patient (4.7%) had an infectious etiology. Five patients were on β-blocker therapy, but none were seen with rupture. However, eight of the remaining 16 patients (50%) without β-blockade had rupture. Thirteen patients (62%) had calcified aneurysms, but all ruptures were seen in noncalcified aneurysms. Operative intervention occurred in 11 of the 21 patients (52%). All eight patients with rupture underwent operation, including six ligations and one successful embolization, and one patient died before completion of repair. The operative mortality rate was 37.5% for ruptured aneurysms. Elective repair included one prosthetic graft, one excision and patch angioplasty, and one embolization, with no mortality. Ten of the 21 patients (48%) with SMA aneurysms were observed, and all were alive and well at a mean of 67 months' follow-up (range, 2 to 148 months). Conclusion: SMA aneurysms are rare but appear to have a higher risk of rupture than previously reported. Male patients and patients with noncalcified aneurysms appear to have a greater risk of rupture. β-Blockade may have some protective effect against aneurysm rupture. Intervention is reasonable in all patients at good operative risk with SMA aneurysms, considering the high rupture rate in our series.