The hypotensive effect of oral nitroglycerin on portal venous pressure in patients with cirrhotic portal hypertension

Abstract Nitroglycerin was administered orally to seven patients with cirrhosis and portal hypertension, to determine whether portal venous pressure (PVP) may be lowered without the systemic effects associated with its intravenous or sublingual use. PVP was measured via direct cannulation of the portal vein transhepatically using a Chiba needle. PVP decreased from 29 (s.d. = 4) to 22.7 (s.d. = 3.7) mmHg (22% mean fall) following 1.2 mg nitroglycerin with onset 7–15 min following ingestion, and the response persisted for up to 150 min. This was not associated with headache in any patient. Although a decrease in blood pressure was seen in most patients, this temporally followed the fall in PVP suggesting that it was a secondary response. Sublingual nitroglycerin was given to two patients without change in PVP yet both experienced severe headache. These findings support the hypothesis that oral nitroglycerin is delivered differentially to the portal venous bed with differential effects on PVP. Further studies are needed to evaluate this agent and this strategy for their potential role in long-term control of portal pressure.