Serial exercise testing and prognosis in selected patients considered for cardiac transplantation

This study sought to examine the predictive value of variables obtained from serial maximal exercise testing, echocardiography, and ejection fraction in patients referred as potential heart transplant candidates.

Variables such as peak VO2, left ventricular dimensions, ejection fraction, and hemodynamic measurements are known to predict prognosis in heart failure, but there are few data on the impact of serial measurements of these variables on subsequent mortality.

Two hundred sixty-three ambulatory patients with severe heart failure referred as potential candidates for heart transplantation who underwent two exercise tests (mean 7.8 months apart) after optimal medical treatment were identified. At the same two time points, echocardiography was performed in 106 (37%) and ejection fraction was measured in 84 (30%). During a mean follow-up period of 3.9+/-0.1 years, 70 (25%) died and 45 (19%) underwent heart transplantation. Exercise capacity, peak exercise heart rate, and peak exercise systolic blood pressure achieved were all significantly higher among survivors compared with nonsurvivors. Among the survivors a slight increase in peak VO2 and ejection fraction were observed, but there were no significant differences in the changes of any of the measured variables between survivors and nonsurvivors. There were no significant differences in survival between patients with increased versus those with decreased peak VO2, left ventricular dimensions, or ejection fraction.

Although peak VO2, left ventricular dimensions, and ejection fraction predict survival, changes in these parameters do not add any prognostic information in patients with severe heart failure who have been stabilized with optimal medical treatment. Routine use of these procedures therefore does not seem to be warranted and should be performed only in the context of a specific clinical situation. Serial measurements of these parameters do not appear to be useful in the risk stratification of patients referred for heart transplantation.