Prognostic implications of fluid balance in ST elevation myocardial infarction complicated by cardiogenic shock

Background: Positive fluid balance has been associated with adverse outcomes in patients admitted to general intensive care units. We analysed the relationship between a positive fluid balance and its persistence over time in terms of in-hospital outcomes among ST elevation myocardial infarction (STEMI) patients complicated by cardiogenic shock. Methods: We retrospectively studied fluid intake and output for 96 hours following hospital admission in 48 consecutive adult patients with STEMI complicated by cardiogenic shock, all undergoing primary angioplasty. Daily and accumulated fluid balance was registered at up to 96 hours following admission. The cohort was stratified into two groups based on the presence or absence of positive fluid balance on day 4. Patients' records were assessed for in-hospital adverse outcomes, as well as 30-day all-cause mortality. Results: A positive fluid balance was present in 19/48 patients (40%). Patients with positive fluid balance were older and more likely to be treated by intra-aortic balloon counter-pulsation and antibiotics. These patients were more likely to develop acute kidney injury and to need new intubation and were less likely to have renal function recovery as well as successful weaning from mechanical ventilation (p < 0.05 for all). Patients with positive fluid balance had higher 30-day mortality (68% vs. 10%; p < 0.001). In a multivariate Cox regression model, for every 1-L increase in positive fluid balance, the adjusted risk for 30-day mortality increased by 24% (hazard ratio: 1.24, 95% confidence interval: 1.07-1.42; p=0.003). Conclusions: A positive fluid balance was strongly associated with higher 30-day mortality in STEMI complicated by cardiogenic shock.