Transthoracic echocardiographic and cardiopulmonary exercise testing parameters in Eisenmenger's syndrome Association with six-minute walk test distance

The six-minute walk test (6MWT) evaluates the functional exercise capacity in patients with cardiopulmonary disease. We aimed to investigate the association between 6MWT distance and transthoracic echocardiographic (TTE) findings as well as cardiopulmonary exercise testing (CPET) parameters in Eisenmenger's syndrome (ES) patients waiting for heart-lung transplantation on their initial admission to our center. A total of 23 patients with ES (12 women, 11 men; mean age, 28.2 +/- 8.1 years) were included in the study. The correlation between 6MWT distance and CPET and TTE findings was retrospectively analyzed. The most frequent underlying heart diseases were ventricular septal defect (VSD) with complex congenital heart disease (n = 10, 43 %) and isolated VSD (n = 7, 30 %). The 6MWT distance was 349.7 +/- 77.4 m in the study group. An inverse correlation was found between 6MWT distance and systolic pulmonary arterial pressure (SPAP) measured with TTE (r = -aEuro parts per thousand 0.445; p = 0.03). All patients underwent CPET at the first visit. Mean VO2 max was 14.9 +/- 3.3 ml/kg/min and the VE/VCO2 rate was 50.4 +/- 9.2 %. No significant correlation was observed between 6MWT and CPET findings. SPAP, which did not display any correlation with CPET findings, was the only independent predictor of 6MWT distance. We suggest that 6MWT distance may be more suitable than CPET in the follow-up of ES patients. Further prospective, randomized, controlled trials are necessary to make more robust interpretations of this issue.