Background Accurately establishing prognosis in severe heart failure has be
come increasingly important in assessing the efficacy of treatment modaliti
es and in appropriately allocating scarce resources for transplantation. Pe
ak exercise oxygen uptake appears to have on important role in risk stratif
ication of patients with heart failure, but the optimal cutpoint value to s
eparate survivors from nonsurvivors is not clear.
Methods Six hundred forty-four patients referred for heart failure evaluati
on over a 10-year period participated in the study. After pharmacologic sta
bilization at entrance into the study, all participants underwent cardiopul
monary exercise testing. Survival analysis was performed with death as the
end point. Transplantation was considered a censored event. Four-year survi
val was determined for patients who achieved peak oxygen uptake values grea
ter than and less than 10, 11, 12, 13, 14, 15, 16, and 17 mL/kg/min.
Results Follow-vp information was complete for 98.3% of the cohort. During
a mean follow-up period of 4 years, 187 patients (29%) died and 101 underwe
nt transplantation. Actuarial 1- and 5-year survival rates were 90.5% and 7
3.4%, respectively. Peak ventilatory oxygen uptake (VO2) was an independent
predictor of survival and was a stronger predictor than work rate achieved
and other exercise and clinical variables. A difference in survival of app
roximately 20% was achieved by dichotomizing patients above versus below ea
ch peak VO2 value ranging between 10 and 17 mL/kg/min, Survival rate was si
gnificantly higher among patients achieving a peak VO2 above than among tho
se achieving a peak VO2 below each of these values (P < .01), but each cutp
oint was similar in its ability to separate survivors from nonsurvivors.
Conclusion Peak VO2 is an important measurement in predicting survival from
heart failure, but whether on optimal cutpoint exists is not clear. Peak V
O2 may be more appropriately used as a continuous variable in multivariate
models to predict prognosis in severe chronic heart failure.