Background: Treadmill exercise testing provides prognostic and clinical information that is not available for patients with lower extremity disabilities who undergo pharmacologic stress tests. We sought to determine whether arm ergometer (AXT) exercise capacity in resting metabolic equivalents (METs) and hemodynamic and electrocardiographic responses to AXT are predictors of survival, myocardial infarction (MI), or coronary revascularization, individually or as a composite.
Methods: A prospective cohort of 359 veterans aged 63 +/- 11 (SD) years, who were unable or unwilling to perform treadmill exercise, underwent AXT stress testing for clinical reasons between 1997 and 2002 and were followed for 63 +/- 24 months to an end point of death or December 31, 2006. Average annual mortality, MI, revascularization, and combined event rates were 5.2%, 1.7%, 2.2%, and 7.1%, respectively.
Results: By univariate analysis, AXT METs were highly predictive of survival (P < .01; hazard ratio 0.58, 95% confidence interval 0.46-0.70). A greater delta (peak-rest) heart rate, peak exercise systolic blood pressure, and rate pressure product were associated with survival and event-free outcome (all P < .02). A positive exercise electrocardiogram was predictive of death, revascularization, and combined events (all P < .01), and borderline predictive of MI (P = .058). By Wald chi(2) analysis, age, clinical variables, exercise capacity in METs, a positive exercise electrocardiogram, and delta heart rate all had statistically significant incremental prognostic value (P < .05) for survival.
Conclusion: In older veterans with lower extremity disabilities and more comorbidities than most study populations, arm exercise capacity, delta heart rate, and a positive electrocardiogram were independently predictive of survival and/or adverse cardiovascular outcomes.