6MWT Predicts Survival Better Than CPET in Patients with Stable Cardiomyopathy

Aims: The prognostic value of different clinical, echocardiographic and functional parameters was evaluated in clinically stable outpatients with heart failure due to idiopathic dilated cardiomyopathy (DCM).
Study Design: Observational prospective study.
Methodology: 56 patients suffering from idiopathic dilated cardiomyopathy in waiting list for heart transplantation (33 men and 23 women, mean age 56.4 years) and in clinical stable conditions for a minimum of 3 months underwent baseline clinical evaluation, echocardiogram, 6 minute walk test (6 MWT) and cardiopulmonary exercise test (CPET). They were followed for an average period of 26.5 months to assess event-free survival (death, heart transplantation).
Results: During follow-up period 23 patients died, 21 for cardiovascular causes. 4 patients underwent heart transplantation. Age and sex were not related to survival. We found a significant predictive value for 6MWTD (at 1 year event-free survival was 53% for a distance <300 m), but not for VO2 peak or respectively anaerobic threshold (AT). At multivariate analysis using Cox-stepwise regression model NYHA class, 6MWTD, left ventricular ejection fraction and left ventricular end diastolic diameter were independent prognostic markers of survival.
Conclusion: An advanced NYHA class, a higher LVEDD and a distance of < 300m at 6MWT are useful prognostic markers of event free survival in outpatients with stable DCM while CPET was not.