Serial Follow-Up Evaluation With Computed Tomography After Conservative Medical Treatment in Patients With Symptomatic Spontaneous Isolated Superior Mesenteric Artery Dissection.

Objective: There is no detailed information available about trend in the morphological change after conservative medical treatment in patients with symptomatic spontaneous isolated superior mesenteric artery dissection (SISMAD).

Methods: We enrolled 27 consecutive patients with symptomatic SISMAD who underwent conservative medical treatment between 2006 and 2015. The long-term prognosis, natural history, and serial follow-up computed tomography (CT) findings of risk factors of rupture such as arterial diameter and false lumen enhancement were retrospectively assessed.

Results: Spontaneous isolated superior mesenteric artery dissection usually developed in middle-aged men around 50 years old who had a history of smoking. Follow-up CT was performed at 1 to 6 months, 7 to 12 months, and after 12 months. Superior mesenteric artery (SMA) maximum diameter was 10.3 mm (quartile 9.5-11.3) on initial CT and expanded in 47.1% patients during 1- to 6-month follow-up, which decreased over time ( P < .001 at 7- to 12-month follow-up, P = .001 after 12-month follow-up). On the other hand, false lumen enhancements were revealed in 9 (33.3%) patients on initial CT. The size of false lumen enhancement was expanded in the longest diameter in 35.3% patients and in shortest diameter in 29.4% during 1- to 6-month follow-up. However, the size of false lumen decreased in all patients after 12-month follow-up. All patients were alive without arterial aneurysm rupture and hospital readmission during the median of 523 days (170-799) study period.

Conclusion: We demonstrated that both SMA maximum diameter and false lumen enhancement were transiently expanded in some patients during 6-month follow-up, but no longer expanded after 12-month follow-up. Patients with symptomatic SISMAD could be treated medically with scheduled careful follow-up CT evaluations.