Abstract
Background:
Blood pressure (BP) control in hypertensive patients is crucial to reducing the risk of future cardiovascular events and heart failure. Left ventricular (LV) global longitudinal strain (GLS) can detect early subclinical cardiac dysfunction, even when LV ejection fraction (EF) is normal, and is an important prognostic indicator. It is not known whether poor BP control is associated with subclinical dysfunction by GLS, and whether ambulatory BP (ABP) is superior to office BP measurements in this regard.
Methods:
Two-dimensional speckle tracking echocardiography and 24-hour ABP monitoring were performed in 394 treated hypertensive subjects (mean age 72 ± 9 years; 63% women) with LVEF ≥50% from the Cardiovascular Abnormalities and Brain Lesions (CABL) study. Uncontrolled office BP was defined as systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg; uncontrolled ABP as mean 24-hour systolic BP ≥130 mmHg and/or diastolic BP ≥80 mmHg. Abnormal GLS was defined as a value above the 95% percentile of healthy normotensive subjects from the CABL cohort.
Results:
Office BP was uncontrolled in 188 subjects (47.7%), and ABP in 162 (41.1%). Agreement between these two categorization was low [kappa = 0.16, 95% confidence interval (CI), 0.06-0.26; concordant classification in only 58.4% of subjects]. Subjects with uncontrolled ABP showed significantly worse GLS compared to those with controlled ABP (-16.3 ± 3.0% vs -17.7 ± 2.9%, p<0.0001), whereas GLS was not significantly different between those with uncontrolled vs controlled office BP (-16.8 ± 3.1% vs -17.4 ± 3.0%, p=0.07). After adjustment for pertinent covariates (age, sex, race-ethnicity, body mass index, diabetes mellitus, coronary artery disease and LV mass index), uncontrolled ABP was associated with a higher risk of abnormal GLS (odds ratio = 2.32; 95% CI, 1.33-4.03; p=0.003), while uncontrolled office BP was not (odds ratio = 1.30; 95% CI, 0.76-2.22; p=0.35).
Conclusions:
Uncontrolled 24-hour ABP is strongly associated with LV subclinical dysfunction in hypertensive subjects with normal LVEF. Assessing BP control with ABP monitoring may refine the risk stratification of treated hypertensive patients for early LV dysfunction.