Abstract 3106: Are we Considering the Best Hemodynamic Predictor of Cardiovascular Death?
Introduction: While prognostic importance of exercise capacity (in [METs]) is well established, there is controversy regarding the relative prognostic potential of other hemodynamic responses. The high correlation of these variables conflicts with the assumptions of survival analysis models.
Objective: To assess the prognostic power of double product (DP) because it combines heart rate (HR) and systolic blood pressure (SBP).
Methods: From a total of 1959 consecutive patients referred for exercise testing at the Palo Alto Veterans Affairs Medical Center from 1997 to 2004, we studied 1759 male veterans (mean ± SD age, 57 ± 12 years) free of heart failure. DP was calculated by multiplying SBP and HR; variables and their products were subtracted to obtain the differences between rest and maximal exercise (reserve) and recovery (HRR). The hemodynamic variables were analyzed using multiple linear regressions and Cox hazard models with cardiovascular death as the outcome.
Results: There were 157 all-cause deaths, with 53 of the deaths being due to cardiovascular causes (34%) during a median follow up of 5.2 years. Though most of the hemodynamic variables were individually significant in Cox analysis, when age, DP reserve, METs and HRR were entered together, only age and DP reserve were chosen. Of all hemodynamic measurements considered, DP reserve was the strongest predictor of cardiovascular prognosis after adjustment for β-blocker use (Wald Z-score, −5.12; P<0.001).
Conclusions: In patients referred for exercise testing, DP reserve had greater prognostic power than METs, maximal HR or SBP, or HR recovery.