Doppler ultrasonographic findings on hepatic arterial vasospasm early after liver transplantation

Objective. Hepatic arterial vasospasm has not been well recognized clinically as a post-liver transplant vascular complication because of the lack of sufficient data and diagnostic standards. The goal of this study was to provide new evidence and a diagnostic model for the clinical appreciation of hepatic arterial vasospasm and evaluate the role of ultrasonography in the diagnostic process. Methods. Nine post-orthotopic liver transplant cases were retrospectively reviewed. Multiple clinical measurements were analyzed. Routine Doppler ultrasonography was performed within 24 hours, and additional ultrasonographic examinations were conducted as indicated. Each of the 9 patients was given a single 10 mg dose of nifedipine sublingually and monitored by ultrasonography when vasospasm was suspected on the basis of the Doppler ultrasonographic results. Results. Doppler ultrasonography showed high-resistance hepatic arterial flow with absence of antegrade flow and even reversal of flow during diastole both extra hepatically and intrahepatically in all cases. Ten to 45 minutes after administration of the vasodilator, antegrade diastolic flow was observed along the course of the main hepatic artery and its intrahepatic branches with the resistive indices decreasing on average from 1.0 to 0.76. In addition, the peak systolic velocities increased from 57 cm/s before nifedipine administration to 77 cm/s after administration. Conclusions. High-resistance hepatic arterial flow (resistive index = 1) early after liver transplantation is indicative of hepatic arterial vasospasm if it responds to vasodilators. Doppler ultrasonography is a useful tool for the diagnosis of this vascular complication.