Peak exercise SBP and future risk of cardiovascular disease and mortality

Patterns of systolic blood pressure response at the end of exercise and mortality and morbidity in patients referred for exercise testing

OBJECTIVES

Peak exercise systolic blood pressure (SBP) is associated with future cardiovascular disease (CVD) and mortality. We aimed to evaluate the predictive value of different SBP patterns at the end of exercise with these outcomes.

METHODS

We studied 6329 adults (45% women) referred for exercise testing, with test duration of 6-14 min, maximal effort and valid SBP measurements at the end of exercise. The two last SBPs were indexed to work rate (mmHg/Watt), defining responses as: drop (negative change), plateau (no change), slow (lower tertile of increase), intermediate (middle tertile) and steep (upper tertile). Data were cross-linked with nationwide disease and mortality registries. Associations with all-cause mortality and incident CVD were analysed using Cox proportional hazards regression (hazard ratio (HR), 95% confidence interval), using slow SBP increase as reference, adjusted for sex, age, body mass index, baseline CVD (mortality analysis only), beta-blockers and exercise capacity (peak Watt).

RESULTS

The prevalence of SBP responses at the end of exercise were drop (1.1%), plateau (15.0%), slow (30.4%), intermediate (25.2%) and steep increase (28.3%). Follow-up was 8.8±3.4 years. Compared with a slow increase, the adjusted all-cause mortality risks were not statistically different for a drop (HR 1.16 (0.50-2.65)), plateau (HR 1.19 (0.85-1.66)), intermediate (HR 1.24 (0.93-1.66)) or steep SBP increase (HR 1.16 (0.89-1.52)). CVD risk was increased in those with a SBP drop (HR 3.10 (1.85-5.19), but not significantly for plateau (HR 1.17 (0.92-1.48)), intermediate or steep SBP increases (HRs 0.99-1.00).

CONCLUSION

Subjects with a slow SBP increase at the end of exercise tended to have the lowest mortality risk, although no SBP response pattern predicted all-cause mortality independently. CVD risk was strongly increased in patients with a drop in SBP and tended to be increased (non-significantly) also in patients with a plateau in SBP at the end of exercise, in comparison with increasing SBP.

Exercise systolic blood pressure response during cycle ergometry is associated with future hypertension in normotensive individuals

AIMS

We aimed to investigate the association between the exercise systolic blood pressure (SBP) response and future hypertension (HTN) in normotensive individuals referred for cycle ergometry, with special regard to reference exercise SBP values and exercise capacity.

METHODS AND RESULTS

In this longitudinal cohort study, data from 14 428 exercise tests were cross-linked with Swedish national registries on diagnoses and medications. We excluded individuals with a baseline diagnosis of cardiovascular disease or HTN. The peak exercise SBP (SBPpeak) was recorded and compared with the upper limit of normal (ULN) derived from SBPpeak reference equations incorporating age, sex, resting SBP, and exercise capacity. To evaluate the impact of exercise capacity, three SBP to work rate slopes (SBP/W-slopes) were calculated, relative to either supine or seated SBP at rest or to the first exercise SBP. Adjusted hazard ratios [HRadjusted (95% confidence interval, CI)] for incident HTN during follow-up, in relation to SBP response metrics, were calculated. We included 3895 normotensive individuals (49 ± 14 years, 45% females) with maximal cycle ergometer tests. During follow-up (median 7.5 years), 22% developed HTN. Higher SBPpeak and SBPpeak > ULN were associated with incident HTN [HRadjusted 1.19 (1.14-1.23) per 10 mmHg, and 1.95 (1.54-2.47), respectively]. All three SBP/W-slopes were positively associated with incident HTN, particularly the SBP/W-slope calculated as supine-to-peak SBP [HRadjusted 1.25 (1.19-1.31) per 1 mmHg/10 W].

CONCLUSION

Both SBPpeak > ULN based on reference values and high SBP/W-slopes were associated with incident HTN in normotensive individuals and should be considered in the evaluation of the cycle ergometry SBP response.

Integrative Interpretation of Cardiopulmonary Exercise Tests for Cardiovascular Outcome Prediction: A Machine Learning Approach

Integrative interpretation of cardiopulmonary exercise tests (CPETs) may improve assessment of cardiovascular (CV) risk. Here, we identified patient phenogroups based on CPET summary metrics and evaluated their predictive value for CV events. We included 2280 patients with diverse CV risk who underwent maximal CPET by cycle ergometry. Key CPET indices and information on incident CV events (median follow-up time: 5.3 years) were derived. Next, we applied unsupervised clustering by Gaussian Mixture modeling to subdivide the cohort into four male and four female phenogroups solely based on differences in CPET metrics. Ten of 18 CPET metrics were used for clustering as eight were removed due to high collinearity. In males and females, the phenogroups differed significantly in age, BMI, blood pressure, disease prevalence, medication intake and spirometry. In males, phenogroups 3 and 4 presented a significantly higher risk for incident CV events than phenogroup 1 (multivariable-adjusted hazard ratio: 1.51 and 2.19; p ≤ 0.048). In females, differences in the risk for future CV events between the phenogroups were not significant after adjustment for clinical covariables. Integrative CPET-based phenogrouping, thus, adequately stratified male patients according to CV risk. CPET phenomapping may facilitate comprehensive evaluation of CPET results and steer CV risk stratification and management.

Clinical and Prognostic Value of Exaggerated Blood Pressure Response to Exercise

The hypertensive response to exercise testing, defined as exaggerated blood pressure response (EBPR), has been documented to be independently associated with unhealthy conditions, carrying an increased risk of future hypertension, cardiovascular (CV) morbidity and mortality. In treated hypertensives, EBPR is a marker of uncontrolled hypertension, a condition previously undetected by office blood pressure (BP) measurements at rest; EBPR may also detect masked hypertension, a phenotype characterized by normal BP values in the medical environment but elevated home or ambulatory BP monitoring (ABPM). The aim of the present review is to provide a comprehensive and up-dated information on the clinical importance of EBPR targeting the following issues: (I) definition and prevalence; (II) underlying mechanisms; (III) clinical correlates and association with subclinical organ damage; (IV) predictive value; (V) clinical decision making.

Prognostic implications of structural heart disease and premature ventricular contractions in recovery of exercise

Premature ventricular contractions (PVCs) during recovery of exercise stress testing are associated with increased cardiovascular mortality, but the cause remains unknown. We aimed to evaluate the association of PVCs during recovery with echocardiographic abnormalities, and their combined prognostic performance. Echocardiographic abnormalities [reduced left ventricular (LV) ejection fraction, valvular heart disease, LV dilatation, LV hypertrophy, or increased filling pressures] and PVCs during recovery were identified among patients having undergone both echocardiography and exercise stress test. Among included patients (n = 3106, age 59 ± 16 years, 55% males), PVCs during recovery were found in 1327 (43%) patients, among which the prevalence of echocardiographic abnormalities was increased (58% vs. 43%, p < 0.001). Overall, PVCs during recovery were associated with increased cardiovascular mortality (219 total events, 7.9 [5.4–11.1] years follow-up; adjusted hazard ratio (HR [95% confidence interval]) 1.6 [1.2–2.1], p < 0.001). When analyzed in combination with either presence or absence of echocardiographic abnormalities, PVCs during recovery were associated with increased risk when such were present (HR 3.3 [1.9–5.5], p < 0.001) but not when absent (HR 1.5 [0.8–2.8], p = 0.22), in reference to those with neither. Our findings provide mechanistic insights to the increased CV risk reported in patients with PVCs during recovery.