The diastolic blood pressure U-curve

Abstract

Abstract Introduction It is known that low diastolic blood pressure (DBP) at admission is associated with short-term cardiovascular events after acute coronary syndrome (ACS). However, there is a lack of further investigation into the nonlinear relationship between admission diastolic blood pressure (DBP) and adverse outcomes of ACS patients. Objective To investigate the relationship between admission diastolic blood pressure and subsequent cardiovascular mortality in patients with acute coronary syndrome. Methods Retrospective study of patients with ACS periodically included in our center registry between October/2012 and September/2018. Patients with class killip 4 at admission or that needed ionotropic support during hospitalization were excluded. The association between admission DBP and cardiovascular mortality during the follow-up period among this population was analyzed using multivariate COX regression model. Results were presented according to DBP quartiles: Q1, less than 70 mm Hg; Q2, from 71 to 80 mm Hg; Q3, from 81 to 90 mm Hg; Q4, above 90 mmHg. Results A total of 548 patients were included in this cohort study. Mean patient age was 65.9±13.1 years and 75.2% were men. A nonlinear relation was observed between DBP at admission and cardiovascular mortality over the follow-up. During a median follow-up of 42 months (IQR: 27–59), 47 patients (8.6%) died from cardiovascular causes. After adjusting for potential confounders (age and diabetes mellitus), patients in Q3 had the lowest risk for cardiovascular death by Cox proportional hazard model (HR 0.44; 95% CI: 0.16–1.00). Meanwhile, compared with Q1, Q3 patients had significantly lower risk for cardiovascular death (HR 0.35, 95% CI: 0.13–0.92). Conclusion Among patients admitted for ACS, there is a U curve relationship between admission DBP and risk for cardiovascular death. These results could be explained by a reduction in diastolic coronary blood flow which influences myocardial oxygen supply relative to the necessary demand in an ACS. Funding Acknowledgement Type of funding sources: None.