Abstract Background Hypotension is a recognized predictor of mortality in the cardiac intensive care unit (CICU) (1-3). Although prior studies link lower mean/averaged mean arterial pressure (MAP) to adverse outcomes, they highlight the need for dedicated research on the minimum MAP (mMAP), as mean data may fail to capture the clinical significance of brief, severe hypotensive episodes. Purpose This study aims to investigate the mortality outcomes associated with the mMAP within the first 24 hours of CICU admission and further stratified according to admission diagnoses. Methods This retrospective cohort study included adult CICU patients with available mMAP data (2007-2018). Patient data were extracted including admission diagnoses, critical care therapies (hemodynamic/ventilatory support, continuous renal replacement therapy), comorbidities, vital signs, lab values, and mortality outcomes. MAP was measured either invasively (arterial catheter) or non-invasively (blood pressure cuff). Primary exposure was mMAP, defined as the lowest recorded MAP in first 24 hours of CICU admission. Primary outcome was in-hospital mortality analyzed using logistic regression, before and after multivariable adjustment. Mortality outcomes were analyzed according to mMAP and stratified by admission diagnoses (not mutually exclusive). Results 11,930 patients were included. Median age was 69.4 (58.1, 79.2) years and 37.7% were female. Admission diagnoses included heart failure (48.7%), acute coronary syndrome (42.7%), shock (14.9%), and cardiac arrest (11.8%). Critical care therapies were used in 58.5%. Median mMAP was 54 (47, 62) mmHg. 1080 (9.1%) patients died during hospitalization, including 672 (5.6%) in the CICU. Median mMAP was lower in patients who died in the CICU (46 vs. 55 mmHg, p0.001) and during the hospitalization (47 vs. 55 mmHg, p0.001). In the overall cohort, the lowest mortality was at mMAP of 71-75 mmHg. Patients with lower mMAP had higher mortality across admission diagnosis subgroups (Fig1). The mMAP associated with the nadir mortality was slightly higher for acute coronary syndrome or cardiac arrest patients (66-70 mmHg) than for heart failure or cardiogenic shock patients (61-65 mmHg) (Fig2). Each 5 mmHg increase in mMAP was associated with lower in-hospital mortality in patients with (unadj OR 0.81 0.79-0.84, AUC 0.64) and without (unadj OR 0.76 0.71-0.82, AUC 0.67) critical care therapies. Conclusion Our findings re-affirm that hypotension is a significant predictor of mortality, consistent across all admission diagnoses. Notably, the mMAP range associated with the lowest in-hospital mortality was slightly lower for patients with circulatory failure (heart failure or cardiogenic shock) compared to those with acute coronary syndromes or cardiac arrest. This difference may represent an optimal balance between maintaining perfusion and preventing excessive afterload in the setting of circulatory failure, but further investigation is required.1) Mortality Per mMAP & Admission Diag 2) Nadir Mortality Point
Patel et al. (Fri,) studied this question.