Safe angioplasty of a portacaval shunt requires particular knowledge of the tissue characteristics of an anastomosis and the behavior of a balloon during inflation. The nature and true diameter of a portacaval shunt anastomosis are more difficult to evaluate than those of a peripheral arterial lesion, and complications are potentially more hazardous than those related to peripheral arterial angioplasty. We suggest that in some instances low pressure and incomplete balloon inflation are all that is necessary to yield safe and satisfactory results.