Abstract 3101: Assessment of a Proposed Exercise Ventilatory Classification System in Patients with Heart Failure
Background: Ventilatory efficiency predicts mortality in heart failure patients and is a superior mortality predictor compared to peak oxygen consumption (VO2). Recently, a classification scheme has been developed with the intent to incorporate ventilatory efficiency measurement into the routine clinical assessment of heart failure patients. Therefore, the purpose of this study was to evaluate the proposed classification scheme in a separate cohort of heart failure patients.
Methods and Results: Heart failure patients (n =355, 72% males, age 51 ±10 years) had follow-up for at least 5 years from an exercise test. There were 145 events (133 deaths and 12 emergent cardiac transplants). Ventilatory efficiency was determined as VE/VCO2 slope (37.0 ± 9.0) to peak exercise during ramped treadmill exercise. Kaplan-Meier survival analysis was performed using the previously defined VE/VCO2 slope classification scheme [class I ≤29 (n =59,20% events), class II 30 –35.9 (n =124, 32% events), class III 36 – 44.9 (n =114, 46% events), and class IV ≥45 (n =58, 69% events)] and a higher classification was associated with a significantly worse prognosis (p<0.001). VE/VCO2 slope was the most significant predictor of mortality in a multivariable Cox model including peak VO2, ejection fraction, systolic blood pressure, sex, etiology, and heart rate.
Conclusion: The risk of death increases significantly with increasing VE/VCO2 slopes. These results are consistent with the development of the classification scheme and these findings suggest that such classification of patients is a reasonable means of assessing mortality risk in patients with heart failure