Aneurysms of the Superior Mesenteric Artery in Infective Endocarditis: A Case Series

Our primary endpoint was to determine the prevalence of superior mesenteric artery aneurysms (SMAAs) in infectious endocarditis (IE) patients.

Retrospective study of 474 IE-patients (2005-2020) with abdominal computed tomography-angiography (CTA): the data of 10 SMAA-IE-patients (2.1%) are analyzed.

The median age of the 10 patients was 50.4 years (6 men). Microorganisms were Streptococcus spp. (n=6), Gemella spp. (n=2), Staphylococcus aureus (n=1), Enterococcus faecalis (n=1). Aneurysms were saccular (n=9), fusiform (n=1). Five SMAAs were partially thrombosed. Three patients presented acute abdominal pain, associated with partial thrombosis. Three became symptomatic: SMAA growth (n=2) and delayed aneurysm, enlargement, rupture, and bowel ischemia (n=1). Four were small (<25 mm), 6 were large (25-70 mm), mostly distally located (6/10). Five (3 small, 2 large) regressed under antibiotic therapy alone, 2 (25 and 40 mm) underwent coil embolization. Three underwent surgery (30, 50, and 60 mm), because of large aneurysm at SMA origin, rapid enlargement and rupture, and bowel ischemia. The outcome was favorable (mean follow-up: 43.5 months; range: 9-72).

Abdominal pain, vomiting, diarrhea, occurring in a patient with a current or recent history of IE should be carefully evaluated by CTA. Symptomatic, growing aneurysms and fusiform aneurysms mainly underwent an operative repair. Five silent aneurysms (<20 mm, n=2; >20 mm, n=3) were safely monitored under antibiotic therapy, enhancing the need to further have cross-sectional imaging of the visceral circulation in all cases of left-sided IE to detect asymptomatic aneurysms. SMAAs can regress, thus conservative management of small asymptomatic ones is possible.Clinical ImpactIn our series of superior mesenteric artery infectious aneurysms (SMAA) in infective endocarditis (IE) patients (incidence: 2.1%), symptomatic, growing aneurysms and fusiform aneurysms mainly underwent an operative repair. Five silent aneurysms (<20mm, n=2; >20mm, n=3) were safely monitored under antibiotic therapy. Our study showed first, the need to have cross-sectional imaging of the visceral circulation in all cases of left sided infective endocarditis. Obviously, abdominal CT-angiography monitoring is also a cornerstone of the efficacy of the antibiotic regimen. Second, SMAAs in IE patients can regress: thus conservative management of small asymptomatic ones is possible.