Cumulative blood pressure exposure and global and regional cardiac structure and function: the MESA study

Abstract

Aims This study examined the associations between decade-long cumulative blood pressure (BP) exposure and global/regional myocardial structure and function independent of current BP levels. Methods and results We analysed 3015 adults (aged 69.0 ± 9.2 years) from the Multi-Ethnic Study of Atherosclerosis (MESA) who underwent cardiac magnetic resonance (CMR) imaging at Year 10 (Exam 5, 2010-12). Measures included left ventricular (LV) parameters, global/regional myocardial function via tagged CMR, interstitial myocardial fibrosis via T1-mapping measures (native T1 and extracellular volume fraction), and myocardial scar via late gadolinium enhancement. We used cumulative exposure to BP through baseline and up to Exam 5 (millimetres of mercury × year) to represent long-term exposure to BP levels. Linear regression, logistic regression, and generalized additive models were used to quantify the association of cumulative BP parameters with measures of cardiac structure and function. Higher cumulative systolic BP (SBP), independent of current SBP, correlated with increased LV mass index [1.93 g/m2 per standard deviation (SD)], worse global/regional circumferential strain (0.24-0.38% lower absolute values per SD), and greater myocardial scar risk [odds ratio (OR): 1.36, 95% confidence interval (CI): 1.02-1.82 per SD]. Cumulative diastolic BP (DBP) was associated with circumferential strain, showing nearly J-shaped relationships after adjusting for current DBP (all P < 0.05). In non-hypertensive individuals with BP consistently below the hypertension threshold, cumulative SBP remained significantly associated with LV mass index and strain but not myocardial scar (OR: 1.53, 95% CI: 0.82-2.87, P = 0.19). Conclusion Higher cumulative BP was associated with worse global and regional cardiac structure/function and myocardial scar, independent of a single BP at the time of imaging, and was still observed to some extent in non-hypertensive individuals who consistently maintained BP levels below the hypertension threshold.