Impact of splenic circulation: non-invasive microbubble-based assessment of portal hemodynamics.

Abstract

The objective was to examine the effect of splenic circulation using a microbubble agent to assess the severity of portal hypertension. This prospective study consisted of 91 subjects (63.0 ± 12.6 years, 30-86; 60 males, 31 females), 62 cirrhosis and 29 controls, who underwent both Doppler ultrasound and contrast-enhanced ultrasound with a perflubutane microbubble agent. Two microbubble-based parameters for splenic circulation, the minimum circulation time (MCT, s) and the peak enhancement time (PET, s), were assessed with respect to the hepatic venous pressure gradient (HVPG) and other clinical findings. The MCT and PET showed significant differences between cirrhosis (5.7 ± 1.8; 14.6 ± 3.0) and controls (4.0 ± 1.9, p < 0.0001; 8.9 ± 2.3, p < 0.0001), respectively. However, only PET offered positive correlations with wedged hepatic venous pressure (r = 0.4648, p = 0.0001) and HVPG (r = 0.4573, p = 0.0001). The area under the receiver operating characteristics curve to identify HVPG ≥ 10 mmHg, and 12 mmHg was 0.76 and 0.76, respectively. The microbubble-based non-invasive assessment of the splenic circulation is effective to identify the severity of portal hypertension presumably by reflecting congestion of splenic venous flow due to increased portal venous pressure.