EXTRAHEPATIC PORTAL-VEIN STENOSIS IN RECIPIENTS OF LIVING-DONOR ALLOGRAFTS - DOPPLER SONOGRAPHY

OBJECTIVE. The aim of this study was to describe the appearances obtai ned and the pitfalls involved with the use of Doppler sonography for d etecting portal vein stenoses after surgery in 198 recipients of pedia tric reduced-size liver transplants. SUBJECTS AND METHODS. We analyzed sonographic and Doppler Studies after surgery for 167 children (avera ge, 2.5 years old) who were recipients of 198 left lobe or left latera l segment liver segments (79 living-donor allografts and 119 cadaveric grafts). Sonographic and Doppler studies were performed either on the basis of clinical evidence of por tal hypertension or as part of a sc reening protocol. Demographic and surgical data were compared with the incidence of portal Vein stricture. We calculated pressure gradients from Doppler jet velocities and compared them with gradients measured manometrically from direct portography in 12 patients. Imaging criteri a that indicated portal vein stenoses were (1) a visualized portal vei n diameter of 2.5 mm or less, (2) an acceleration of flow at the struc ture or a poststenotic jet of portal vein flow revealed by Doppler ima ging, or (3) both. Stenoses meeting these criteria were verified by su rgical or angiographic identification. RESULTS. Seventeen (22%) portal vein stenoses were detected in recipients of the 79 living-donor live r transplants, whereas three (3%) were detected in recipients of the 1 19 cadaveric grafts (p < .005). The use of cryopreserved venous extens ion grafts was the most significant parameter of correlation (p < .025 ). Doppler sonography predicted the stenoses in all cases, although it overestimated the pressure gradients in all but one of the verified c ases. Intrahepatic portal vein flow was frequently normal in the prese nce of significant extrahepatic portal vein stenosis. CONCLUSION. Diag nosis of portal vein stenosis in recipients of living-donor allografts requires real-time visualization of the entire length of the portal v ein, combined with spectral and color Doppler investigations of the po rtal and splenic veins and a search for collateral vessels. Visualizat ion of each component alone may be insufficient. In our study, when ca rt. was taken to follow this procedure, sonography accurately showed a ll angiographically verified portal vein stenoses, although pressure g radients frequently were inaccurate. A protocol for periodic follow-up with real-time and Doppler sonography is crucial for pediatric patien ts to permit early identification of portal vein stenoses.