Introduction: Pulse pressure (PP) is directly influenced by cardiac output and, hence, changes with physical activity. To our knowledge, no study has evaluated the prognostic significance of PP response to exercise. We studied the relationship between a novel parameter, the pulse pressure stress index (PPSI), and adverse outcomes in a large clinical registry of adults who were referred for exercise treadmill stress testing.
Hypothesis: Poor PP response to exercise is inversely associated with risk of incident MI or death.
Methods: The PPSI was calculated as PP at peak exercise divided by resting PP and was analyzed categorically (by quartile) and continuously (per 1 unit increase). Multivariable-adjusted Cox proportional hazards models examined the association between baseline PPSI and risk of future myocardial infarction (MI), or mortality.
Results: Among 58,660 FIT participants referred for stress testing without prior MI, mean (SD) age was 53 (13) years, 51% were men, and 29% black. A total of 1,734 incident MI and 6,829 mortality events occurred after a mean (SD) follow-up of 6.1 (4.3) and 11.0 (4.6) years, respectively. There was a graded and monotonic lower risk of events with higher PPSI achieved. For example, compared to quartile 1, the 4th quartile of PPSI was associated with a 12% (95% CI 1%, 39%) lower risk of MI and 31% (95% CI 12%, 40%) lower risk of mortality (TABLE).
Conclusions: An inverse association exists between PP response to exercise and risk of adverse events. Low PP response to exercise may be considered a novel, independent, and readily quantifiable high-risk feature derived from exercise stress testing.