Workload-indexed hypertensive response to exercise across the heart failure spectrum

Objective: Limited evidence is available regarding the impact of workload-indexed hypertensive response to exercise (HRE) in patients at different stages of the heart failure (HF) spectrum. We evaluated the prevalence, pathophysiologic and prognostic correlates of HRE, evaluated by the systolic blood pressure (SBP)/Workload slope, across the HF spectrum as defined by the American College of Cardiology/American Heart Association. Design and method: We prospectively enrolled 58 healthy controls, 201 subjects at risk of developing HF (HF Stages A-B), and 369 patients with a definite diagnosis of HF (Stage C) and either preserved (HFpEF) or reduced (HFrEF) left ventricular ejection fraction. All patients underwent a combined cardiopulmonary-exercise stress echocardiography test. We recorded two SBP measurements for each patient: the first within the first minute of exercise and the last at peak effort. The SBP/Workload slope was calculated as the difference in SBP over the corresponding increment in watts (W): (SBPpeak – SBPfirst)/(Wpeak – Wfirst). In each subgroup, we divided patients according to SBP/Workload slope tertiles, using sex-specific cut-off values; HRE was defined as the highest SBP/Workload slope tertile in each HF stage. A composite of all-cause mortality and hospitalization for cardiovascular reasons was chosen as the primary outcome. Results: The median SBP/Workload slope was 0.53 (interquartile range 0.36 - 0.72) mmHg/W and was steeper in women than men in all subgroups. After adjusting for age and sex, SBP/Workload slope in controls was similar to HFrEF but significantly lower than Stages A-B and HFpEF. In all HF stages, patients with HRE showed significantly lower peak oxygen consumption and peripheral oxygen extraction. After a median follow-up of 16 months, HRE was independently associated with adverse outcomes (Hazard Ratio 2.05, 95% confidence interval 1.81 - 5.18). Kaplan-Meier analysis confirmed a worse survival probability in Stages A-B and HFpEF, but not HFrEF. After adjusting for clinical and echocardiographic variables, patients in the highest SBP/Workload tertile had a 47% higher risk of the primary outcome than subjects in the lowest tertile. Conclusions: HRE is associated with peculiar pathophysiological features and possibly worse prognosis in patients in the earliest stages of cardiovascular disease and in those with HFpEF.