Current Understandings of Spontaneous Isolated Superior Mesenteric Artery Dissection

Abstract

Spontaneous isolated superior mesenteric artery dissection (SISMAD) has been known as a rare vascular disease. However it is increasingly reported in these days with the development of advanced imaging technology. Underlying etiology, natural course or an optimal management strategy of SISMAD is not exactly known at the moment. During the past 10 years, we have had an interest in this rare vascular disease and collected clinical and image data in 100 or more patients with SISMAD. In this review article, I would like to describe my current understanding of SISMAD on the base of our recent publications in the major vascular surgery journals.

Keywords: Dissection; Natural course; Superior mesenteric artery.

Fig. 1.

Measurement of distance from the lowest margin of the pancreas to an entry site of dissection on computed tomography scan. Cross-sectional view at the level of (A) the most proximal entry site and (B) lowest margin of pancreas. (C) Three-dimensional reconstructed lateral view showing the relative position of an entry site of spontaneous isolated superior mesenteric artery dissection and pancreas body (P).

Fig. 2.

Limiting streamline patterns (left panels; A1, B1, and C1) and wall shear stress (WSS) distributions (right panels; A2, B2, and C2) according to three branching angles (60°, 90°, and 120°) of the superior mesenteric artery from the aorta.

Fig. 3.

Diagnosis of superior mesenteric artery (SMA) dissection with the characteristic finding of a “double lumen sign” of the SMA on axial views of computed tomography (CT) images (A) and/or dissected segment of SMA on selective mesenteric angiography or CT angiography (B).

Fig. 4.

Angiographic classification of spontaneous isolated superior mesenteric artery dissection.

Fig. 5.

Complete remodeling of superior mesenteric artery (SMA) dissection on follow-up computed tomography (CT) angiogram. (A) Initial CT scan showing double-lumen sign on an axial view (top) and a wind-sock-shaped dissection lesion on the anterior wall of the SMA (type IIa spontaneous isolated superior mesenteric artery dissection) (bottom), (B) follow-up CT angiogram at 7 months after conservative treatment shows disappearance of the double-lumen sign on axial view (top) and complete remodeling of the SMA on a reconstructed view of the SMA (bottom).