Doppler evaluation of arterial complications of adult orthotopic liver transplantation

PURPOSE: The aim of this study was to analyze the role of the resistance index (RI), systolic acceleration time (SAT), and spectral waveform's morphologic characteristics in the sonographic evaluation of the hepatic artery for early detection of stenosis or thrombosis after orthotopic liver transplantation. METHODS: Arterial Doppler sonograms of 174 transplanted livers in 150 patients were analyzed for presence or absence of blood flow, RI, SAT, and peak systolic velocity. A qualitative evaluation of the spectral waveform morphologic characteristics was also made. In patients who had had abnormal findings on sonography, we compared those results with results obtained on multislice helical CT or angiography. RESULTS: At least 1 of the Doppler criteria for hepatic artery stenosis or thrombosis was identified in 25 of the transplants. The findings on multislice helical CT, angiography, or both confirmed the diagnosis of stenosis or thrombosis in 20 of the 25 cases: in 9 of 10 cases of absent hepatic arterial blood flow, 5 of 9 with an RI lower than 0.5, 6 of 7 cases with an SAT longer than 0.08 second, 10 of 11 cases of changes to a tardus-parvus-like spectral waveform, and in the 1 case of a peak systolic velocity greater than 2 m/second. CONCLUSIONS: The most accurate indicator of hepatic arterial stenosis or thrombosis was a change in the spectral waveform to a tardus-parvus pattern, with 91% sensitivity and 99.1% specificity. Among the other parameters, an increase of the SAT value (> 0.08 second), when associated with the morphologic modification of the systolic peak, is a more reliable parameter than the RI for early detection of artery stenosis, especially when the type of anastomosis is unknown.