Association between mean systolic and diastolic blood pressure throughout the follow-up and cardiovascular events in acute myocardial infarction patients with systolic dysfunction and/or heart failure: an analysis from the High-Risk Myocardial Infarction Database Initiative.

Abstract

Observational data have described the association of blood pressure (BP) with mortality as 'J-shaped', meaning that mortality rates increase below a certain BP threshold. We aimed to analyse the associations between BP and prognosis in a population of acute myocardial infarction (MI) patients with heart failure (HF) and/or systolic dysfunction. The datasets included in this pooling initiative are derived from four trials: CAPRICORN, EPHESUS, OPTIMAAL, and VALIANT. A total of 28 771 patients were included in this analysis. Arithmetic means of all office BP values measured throughout follow-up were used. The primary outcome was cardiovascular death. The mean age was 65 ± 11.5 years and 30% were female. Patients in the lower systolic BP (SBP) quintiles had higher rates of cardiovascular death (reference: SBP 121-128 mmHg) [adjusted hazard ratio (HR) 2.49, 95% confidence interval (CI) 2.26-2.74 for SBP ≤112 mmHg, and HR 1.29, 95% CI 1.16-1.43 for SBP 113-120 mmHg]. The findings for HF hospitalization and MI were similar. However, stroke rates were higher in patients within the highest SBP quintile (reference: SBP 121-128 mmHg) (HR 1.38, 95% CI 1.11-1.72). Patients who died had a much shorter follow-up (0.7 vs. 2.1 years), less BP measurements (4.6 vs. 9.8) and lower mean BP (-8 mmHg in the last SBP measurement compared with patients who remained alive during the follow-up), suggesting that the associations of low BP and increased cardiovascular death represent a reverse causality phenomenon. Systolic BP values <125 mmHg were associated with increased cardiovascular death, but these findings likely represent a reverse causality phenomenon.