Pulmonary Transit Time Derived from Pulmonary Angiography for the Diagnosis of Hepatopulmonary Syndrome

Background & Aims: Pulmonary transit time (PTT) is the transit time of blood from the right side of the heart to the left side of the heart. The aim of the present study was to evaluate the role of the PTT derived from pulmonary angiography in the diagnosis of hepatopulmonary syndrome (HPS).

Methods: From December 2014 to September 2015, all patients with chronic liver disease and/or portal hypertension undergoing a venous interventional radiologic procedure at our institution were eligible for inclusion in this prospective study. Pulmonary angiography was performed in all patients, and the PTT, which was defined as the time between opacification of the pulmonary trunk and the right border of the left atrium, was determined.

Results: A total of 53 patients were included, 20 of whom had a positive contrast-enhanced echocardiography result and an elevated alveolar-arterial oxygen gradient were considered to have HPS. PTT was significantly shorter in patients with HPS than in those without [median, 3.34 (interquartile range, 3.01-3.67) seconds vs 4.0 (interquartile range, 3.67-4.17) seconds; P < .001]. The area under the receiver operating characteristic curve of PTT for diagnosing HPS was 0.83 (95% confidence interval, 0.70-0.92). The optimal cut-off value of PTT for diagnosing HPS, based on Youden's index, was 3.55 seconds. The sensitivity, specificity and accuracy of PTT < 3.55 seconds for diagnosing HPS were 70%, 85% and 79% respectively.

Conclusions: Pulmonary transit time derived from pulmonary angiography is useful for diagnosing HPS, especially for patients with intracardiac shunts and inadequate echocardiographic windows.