Outcomes in liver transplant candidates with intracardiac shunting

Abstract

Background and Aims: Contrast enhanced echocardiography (CEE) is done during liver transplantation (LT) evaluation to assess for hepatopulmonary syndrome (intrapulmonary shunting) and portopulmonary hypertension. A subset of these patients are reported to have intracardiac shunting (ICS). However, there is little data on the prevalence of ICS and whether it influences outcomes in LT candidates. We characterized patients with ICS in a cohort of LT candidates. Methods: We perfomed a prospective multi-center cohort study of patients undergoing LT evaluation in seven academic centers in the US, from 2003 to 2006. ICS was defined as the appearance of an "early" right-to-left shunt on CEE. ICS patients were compared to controls that did not have any shunting on CEE. Patients with significant obstructive or restrictive ventilatory defects on pulmonary function tests (PFTs) were excluded. Demographic, clinical and survival data were analyzed. Results: 281 patients with complete CEE, PFT and arterial blood gas data were evaluated. 15 of the 281 patients had ICS (5.3%). The 15 ICS patients were compared to 79 controls. There were no differences in age, gender, race, ethnicity, severity of liver disease, echocardiographic findings or PFTs between ICS patients and controls. HCV was more common in ICS patients compared to controls (73% vs. 37%, p=0.02) and there was a higher prevalence of current smokers in the ICS patients (38% vs. 11%, p=0.02). Of the 15 ICS patients evaluated for LT, 8(53%) were listed, 6(40%) underwent LT and 1(7%) died. On survival analysis, there was no difference in mortality between ICS patients and controls despite adjustment for age, gender, race, MELD, HCV and LT (adjusted hazard ratio =0.21, 95% CI, 0.02-1.81, p=0.15). Conclusions: ICS is present in a small percentage of LT candidates. Its presence does not appear to influence mortality. These findings support that ICS, in the absence of other echocardiographic or pulmonary abnormalities, does not merit further evaluation in LT candidates.