Prognostic value of cardiopulmonary exercise testing using percent achieved of predicted peak oxygen uptake for patients with ischemic and dilated cardiomyopathy

Objectives. We tested the hypothesis that percent achieved of predicted peak oxygen uptake (predicted V̇O₂(max)) improves the prognostic accuracy of identifying high risk ambulatory patients with congestive heart failure considered for heart transplantation compared with absolute peak oxygen uptake (V̇O₂(max)) in 181 patients with ischemic or dilated cardiomyopathy. Background. Peak oxygen uptake during exercise has been shown to be a useful prognostic measurement to risk stratify patients with heart failure. The prognostic value of percent predicted V̇O₂(max) has not been assessed in these patients. Methods. We retrospectively studied 181 ambulatory patients referred to the Saint Louis University Heart Failure Unit. Clinical, hemodynamic (137 patients) and coronary angiographic (145 patients) data were recorded, and all patients underwent symptom-limited cardiopulmonary exercise. Results. During a mean follow-up period of 12 ± 6 months, 26 patients died, and 18 were listed as Status 1 priority for heart transplantation. The actuarial 1- and 2-year survival of the 89 patients who achieved ≤50% predicted V̇O₂(max) was 74% and 43%, respectively, compared with 98% and 90% in the 92 who achieved >50% predicted V̇O₂(max) (p = 0.001). Multivariable analysis selected ≤50% predicted V̇O₂(max) as the most significant predictor of cardiac death (p = 0.007) and cardiac death or Status 1 priority (P = 0.0005). Conclusions. Percent achieved of predicted V̇O₂(max) provides important information that can be used to risk stratify ambulatory patients with heart failure with ischemic or dilated etiology that exceeds that provided by measurement of V̇O₂(max) alone. Patients who achieve >50% predicted V̇O₂(max) have an excellent short-term prognosis when treated medically, and heart transplantation can be safely deferred.