BENEFICIAL HEMODYNAMIC-EFFECTS OF DIPYRIDAMOLE ON PORTAL CIRCULATION IN CIRRHOSIS

Objective: Dipyridamole is a vasodilator that inhibits the cellular up take of adenosine, which physiologically reduces the resistance to hep atic arterial flow inside the liver. This study aims at assessing the acute effect of dipyridamole on functional liver plasma flow (measured as the extrarenal sorbitol clearance) and on the Doppler US Congestio n Index of the portal vein (the ratio between the cross-sectional area of this vein and the mean velocity of portal flow), which correlates with the severity of portal hypertension. Methods: We have determined the extrarenal sorbitol clearance (14 cases) and the Congestion Index (seven cases) before and at 30, 60, and 90 min after the oral administ ration of 25 mg dipyridamole in patients with liver cirrhosis. We also measured the effect of dipyridamole on functional liver plasma flow i n six healthy subjects. Results: Dipyridamole increased the extrarenal sorbitol clearance in controls (+17%, p < 0.01) and in cirrhotic pati ents (+15%, p < 0.01). The drug decreased the portal Congestion Index in all patients, averaging -24% (p < 0.05) 90 min after its oral admin istration. Conclusions: This result was due both to a mean decrease of the portal sectional area and to a mean increase in portal flow veloc ity. In conclusion, these data suggest that dipyridamole should decrea se the vascular resistance to portal flow in cirrhosis; this effect ma y be mediated by an adenosine-dependent vasodilation in the intrahepat ic site or along the portosystemic collaterals. (C) 1998 by Am. Cell. of Gastroenterology.