Mesenteric blood flow is related to disease activity and risk of relapse in ulcerative colitis: a prospective follow up study.

Background: The diagnostic significance of increased splanchnic blood flow in ulcerative colitis is unclear. This prospective study was therefore undertaken to define the role of Doppler sonography in the assessment of disease activity and in the prediction of early relapse.

Subjects/methods: Splanchnic flowmetry was performed in 76 patients with ulcerative colitis (47 with active disease and 29 in remission), six with infectious colitis, and 13 healthy controls during fasting and 30 minutes after ingestion of a standardised meal. Twenty seven of the patients with ulcerative colitis and all patients with infectious colitis were investigated during the active state as well as in clinical remission and followed up for six months. Flow velocity and pulsatility index (PI) of the superior (SMA) and inferior (IMA) mesenteric arteries and the portal vein were related to clinical (Truelove index), laboratory (C-reactive protein), and endoscopic (Sutherland index) parameters of disease activity.

Results: The mean flow velocity of the IMA correlated closest with clinical activity (Truelove, r = 0.41, p<0.005), the PI with C-reactive protein (r = 0.30, p<0.05), and endoscopic activity (r = 0.45, p<0.001). All patients in remission after six months (14/14) or with infectious colitis (6/6) showed an increase in PI of the IMA compared with the initial measurement during active disease (mean increase for ulcerative colitis +36% and for infectious colitis +77%). In contrast, most patients with later relapse or surgery (11/13) had decreased PI during initial remission (mean decrease -12%). The positive predictive value of this index for maintenance of remission was 0.77. Flow variables of the SMA and portal vein displayed weaker correlations.

Conclusions: Flow measurements in the IMA are closely related to clinical and endoscopic disease activity in patients with ulcerative colitis. Repeated measurement of the PI allows estimation of the risk of recurrence.