Systolic blood pressure at Emergency Department presentation and 1-year mortality in acute chest pain patients

Abstract

Background: High blood pressure at rest has been an established risk factor for cardiovascular disease. However the relationship between Systolic Blood Pressure (SBP) and 1-year-mortality among acute chest pain patients presenting to Emergency Department (ED); and effects of preexisting renal insufficiency, hemodynamic stress - as quantified by Brain Natriuretic Peptide (BNP) and chest pain duration, on this relationship is unknown.

Methods: Data was used from APACE (Advantageous Predictors of Acute Coronary Syndrome Evaluation), a prospective observational multicenter study of 1240 ED chest pain patients. SBP at presentation was categorized into quartiles: Q1≤127mmHg; Q2 128-142mmHg; Q3 143-160mmHg; Q4≥161mmHg.

Results: 60 deaths occurred during 1-year. One-year-mortality-rate showed lower Hazard Ratios for Q2, Q3 and Q4 vs Q1 (HR [95% CI]; 0.39 (0.19-0.78), 0.34 (0.17-0.70), 0.35 (0.17-0.72); p<0.01 respectively). Cox model adjusted for various demographic and treatment variables showed that participants in Q3 and Q4 had better prognoses than Q1. Patients showed progressively better prognosis from Q2 through Q4 vs Q1 only in patients who presented to ED with for more than 12h of chest pain duration. Patients with renal insufficiency had lower SBP at presentation than others (p=0.001). There was no association between the outcome and interaction variable of SBP quartiles and BNP (p=0.27).

Conclusion: Acute chest pain patients presenting to ED exhibit an inverse association between SBP at presentation and 1-year-mortality; a relationship which appears stronger in those who present with chest pain of greater than 12h duration.