BACKGROUND AND OBJECTIVES: The intrapulmonary shunt, after a liver transplantation, is expected to improve, but the frequency, and predictors, of improvement are not well known. We studied the frequency of the improvement in the intrapulmonary shunt, and the relation between this improvement and the clinical parameters, using contrast echocardiography in liver transplant candidates. SUBJECTS AND METHODS: Preoperative and postoperative contrast echocardiography, with intravenous agitated saline, was performed in 25 liver transplant candidates(M:F=9:6, mean age=6+/-10). The extent of the intrapulmonary shunt was semi-quantitatively assessed on a grade scale from 0 to 4+, according to the degree of appearance of the contrast in the left heart chambers. The etiology of the underlying chronic liver disease, Child-Pugh classification scores, pulmonary function tests and arterial blood gas analyses were all evaluated. The change in the shunt grade after the liver transplantation, and the association of these changes, with clinical parameters, were also evaluated. RESULTS: Twenty-four(6%) f the 25 patients showed positive results for the intrapulmonary shunt on preoperative contrast echocardiography. At follow up, the shunt was visible in only 5(1%) atients. All 24 patients whose preoperative echocardiography revealed a positive intrapulmonary shunt showed an improvement in the intrapulmonary shunt after the liver transplantation. There was a significant correlation between the improvements in the shunt and the Child-Pugh classification scores(r=0.59, p=0.02). CONCLUSION: Contrast echocardiography is a feasible, noninvasive, method for the detection of changes in the intrapulmonary shunt before and after a liver transplantation, and the intrapulmonary shunt is improved after a liver transplantation in most patients.