U shaped relationship between mean arterial pressure and 28 day mortality in ICU patients with acute myocardial infarction

The current study aims to investigate the correlation between mean arterial pressure (MAP) and the risk of 28-day mortality in patients with acute myocardial infarction. This is a retrospective cohort study utilizing data from the eICU database, focusing on patients with acute myocardial infarction. We employed a multivariable logistic regression model to estimate the relationship between MAP and the 28-day mortality rate. Among 8161 patients with a median age of 67 years, 602 (7.38%) died within 28 days of ICU admission. Smooth curve fitting and generalized additive model analysis identified a threshold effect at MAP of 84 mmHg. We found that when MAP is less than 84 mmHg, a 10 mmHg increase in MAP reduces the mortality rate by approximately 40.13%. Specifically, for every 1 mmHg increase in MAP within this range, the mortality rate decreases significantly by 5% (OR = 0.95, 95% CI (0.93, 0.96), p < 0.0001). Conversely, above the threshold (MAP ≥ 84 mmHg), for every 10 mmHg increase, the mortality rate increases by 34.39% (OR = 1.3439, calculated based on the fact that a 1 mmHg MAP increase causes a 3% mortality rise (OR = 1.03, 95% CI (1.02, 1.03), p < 0.0001), showing a U-shaped association between MAP and 28-day mortality. We found that the baseline MAP at ICU admission, when in the range of 57-110 mmHg, was associated with the lowest 28-day all-cause mortality risk. The relationship between MAP and the risk of 28-day mortality forms a U-shaped curve, indicating that both higher and lower MAP levels are associated with an increased risk of 28-day mortality in ICU-admitted patients.