Prevalence and Clinical Impact of a Subclinical Intrapulmonary Right to Left Shunt Diagnosed by Contrast Echocardiography in Patients with End Stage Hepatic Disease

Lee, Seung Whan; Yang, Yong Mo; Kim, Young Hak; Kim, Jun; Yoo, Hee Seung; Park, Jae Hyeong; Kang, Soo Jin; Song, Jong Min; Kang, Duk Hyun; Song, Jae Kwan

Abstract

BACKGROUND AND OBJECTIVES
The clinical impact of an intrapulmonary right to left shunt, without hypoxia (subclinical IPS), has not been sufficiently evaluated. We investigated the prevalence and clinical impact of a subclinical IPS in patients with end stage hepatic disease.
SUBJECTS AND METHODS
Contrast echocardiography, with hand-agitated saline, was performed in 72 consecutive candidates for a liver transplantation between April 2001 and November 2001. A positive contrast echocardiography indicated an intrapulmonary right to left shunt, and was defined as the delayed appearance of microbubbles in the left side of the heart (3 to 6 beats after the initial appearance in the contrast in the right side of the heart). We compared the clinical events of the patients both with and without a shunt, i.e. death, spontaneous bacterial peritonitis, sepsis, hepatic encephalopathy or variceal bleeding.
RESULTS
A subclinical IPS was detected in 19 of the 72 candidates for a liver transplantation (26.3%). All these candidates were Child class C liver cirrhosis. There were no differences in the baseline characteristics between the patients and those without a shunt in the Child class C (n=57). The mean PaO2 value of the patients with at least a 3+ left ventricular opacification (3 to 4+, n=6) was significantly lower than those with a 1+ to 2+ left ventricular opacification (n=13) (76+/-10 mmHg vs. 103+/-13 mmHg, p< 0.05). The mortality was not significantly difference between the patients with (5%, 1/19) or without (21%, 8/38, p=0.24) a shunt. Also, there were no significant differences in the clinical events during the mean follow-up period of 7+/-3 months (68.4% vs. 83.5% p=0.12).
CONCLUSION
Subclinical IPS's are not uncommon in patients with end stage hepatic disease. The extent of shunting correlates with the level of arterial oxygenation. However, a subclinical IPS is not associated with the mortality or clinical events of the patient selected.