A flattening systolic blood pressure response at the end of ramp exercise testing is not associated with all-cause mortality

Abstract

Abstract Purpose Systolic blood pressure (SBP) is expected to rise linearly during ramp exercise, but sometimes plateaus before the end of exercise. We aimed to examine the predictive value of a plateauing SBP response at the end of a cycle exercise test. Methods We analyzed 9,001 consecutive patients aged ≥18 years with maximal cycle ergometer ramp tests, after excluding subjects with valvulopathy, pacemaker, arrhythmia during the test, or body mass index (BMI) >40kg/m², as well as tests with resting SBP <80mmHg or >200mmHg, exercise SBP <100 mmHg, <2 SBP measurements during the second half of the test or a test duration <4 minutes. The data were cross-linked with nationwide registries for mortality and in- and outpatient hospital diagnoses. The difference in SBP between the two last SBP measurements was standardized to the difference in Watts between the same time points, categorized as i) an SBP decrease (drop), ii) an SBP increase of <2.5 mmHg per 10 Watts increase (flat), iii) an SBP increase of 2.5-15 mmHg/10 Watts (intermediate), and iv) an SBP increase >15 mmHg/10 Watts representing the 97.5th percentile (steep). Hazards ratios (HR, [95% confidence interval, CI]) for all-cause mortality were calculated, stratified for exercise capacity (peak Watt % of predicted) with the intermediate SBP response as reference. Adjustments were made for age, sex, BMI, resting SBP, baseline diagnosis of ischemic heart disease, heart failure, chronic obstructive pulmonary disease, and the use of beta-blockers or anti-hypertensive medication. Results Decreasing, flat, intermediate, and steep SBP responses at the end of exercise were present in 1.1%, 25.6%, 70.8% and 2.5% of patients respectively (Table 1). During median follow-up 8.6 years (interquartile range 5.9–11.6 years) there were 844 deaths. When compared to an intermediate SBP response, a flat SBP response was not associated with all-cause mortality in any of the exercise capacity strata: lowest tertile of Wmax%pred unadjusted HR 0.88 (95% CI 0.69–1.11), middle tertile HR 0.91 (95% CI 0.66–1.24), and highest tertile HR 0.95 (95% CI 0.64–1.41), with HRs remaining non-significant after adjustment for covariates (Table 2). Conclusion In patients referred for exercise testing, a flattening SBP response at the end of exercise was not associated with increased all-cause mortality risk compared to an intermediate SBP response, consistent across the different exercise capacity strata.