Prognostic Significance of the Double Pressure Reserve in Patients with Chronic Heart Failure

ABSTRACT

The double pressure reserve (DPR) has recently been shown to have greater prognostic power than metabolic equivalents, heart rate indices, and systolic blood pressure in healthy subjects. It is unclear whether DPR offers any prognostic value in a heart failure population where variables derived from metabolic gas exchange data pro- vide important prognostic information.

Patients underwent a symptom-limited, treadmill-based exercise test with metabolic gas exchange measure- ments using the modified Bruce protocol. DPR was calculated as the product of peak systolic blood pressure and peak heart rate subtracted from the product of resting systolic blood pressure and resting heart rate values.

363 patients (mean ± SD; age 74±11 years; 81% males; left ventricular ejection fraction 34±6%; peak VO₂ 19.0 ±5.1 mL·kg^-1·min^-1; VE/VCO₂ slope 37 ± 9; double pressure reserve 10,510 ± 6,046 mmHg·beat^-1) were included in thestudy. Peak VO₂ (hazard ratio (HR) = 0.87;P<0.0001, 95% confidence intervals (CI) = 0.75-0.99), VE/VCO2slope(HR1.03;P=0.04; 95% CI =1.00-1.06), and age (HR=1.02;P=0.09; 95% CI =0.98-1.05) were the strongest independentpredictors of mortality. DPR was not a univariate predictor of mortality (P=0.7; HR=1.0; 95% CI = 0.99-1.0).

DPR does not predict mortality in patients with CHF. Traditional prognostic markers derived from metabolic gas exchange including peak VO₂ and the VE/VCO₂ slope are more important.

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