Although mortality and morbidity rates from acute coronary syndromes have been declining considerably, a high risk for death remains after discharge from the intensive care unit (ICU). In this study the authors studied long-term mortality in relation to supine blood pressure in patients admitted to the medical intensive care unit for acute chest pain.
The RIKS-HIA (Registry of Information and Knowledge About Swedish Heart Intensive Care Admissions) registry was used to investigate the relationship between supine admission systolic BP and subsequent mortality in 119151 patients who were treated in the medical ICU over a ten year period. Patients were split into four quartiles for analysis: Q1 ( Systolic BP <128mmHg), Q2 (128-144mmHg), Q3 (145-162mmHg) and Q4 (>162 mmHg). The main outcome measure was total mortality.
The mean follow-up time was 2.47 years. One-year mortality rate by Cox proportional hazard model (adjusting for other risk factors including diastolic BP) found that participants in Q4 (i.e. with the highest systolic blood pressure) had the best prognosis (hazard ratio 0.76 compared to Q2). Patients in Q4 had a 21.7% lower absolute risk compared with Q2, patients in Q3 had a 15.2% lower risk than in Q2, and patients in Q1 had a 40.3% higher risk for mortality than in Q2. Of note, the worse prognosis of Q2 compared to Q4 was similar when restricted to patients with a final diagnosis of angina or myocardial infarction.
In patients admitted to the ICU for chest pain, an inverse relationship exists between admission supine systolic BP and 1-year mortality rate. The study suggests that high blood-pressure in patients with acute coronary syndromes may represent an appropriate reaction to physiological stress.