Hepatic artery hemodynamic responsiveness to altered portal blood flow in normal and cirrhotic livers

PURPOSE: To compare hepatic artery hemodynamic response to altered portal blood flow in normal and cirrhotic livers. MATERIALS AND METHODS: The portal blood flow and hepatic artery pulsatility index were measured by means of duplex ultrasound before and after subjects (eight control subjects and 10 cirrhotic patients) ingested a 500-kcal mixed-liquid meal and during intravenous infusion of vasopressin at a rate of 0.3 U/min (nine control and nine cirrhotic subjects). The hepatic artery buffer index (ratio of maximum change from baseline in hepatic artery pulsatility index to maximum change from baseline in portal blood flow) was also calculated. RESULTS: Meal consumption increased the portal blood flow and hepatic artery pulsatility index in all subjects. The hepatic artery buffer index, however, was significantly lower in cirrhotic than in control subjects (0.67 min/L +/- 0.06 [standard error of the mean] vs 1.54 min/L +/- 0.20, respectively; P < .01). Vasopressin infusion decreased the portal blood flow and hepatic artery pulsatility index in all subjects. Again, the hepatic artery buffer index was significantly lower in cirrhotic than in control subjects (0.28 min/L +/- 0.07 vs 0.50 min/L +/- 0.04, respectively; P < .05). CONCLUSION: Hepatic artery vascular responsiveness to altered portal blood flow is blunted in cirrhotic livers.