Shock Index in Patients Presenting With Acute Heart Failure: A Multicenter Multinational Observational Study

Shock index (SI) has a prognostic role in coronary heart disease; however, data on acute heart failure (AHF) are lacking. We evaluated the predictive values of SI in patients with AHF. Data were retrospectively analyzed from the Gulf Acute Heart Failure Registry. Patients were categorized into low SI versus high SI based on the receiver operating characteristic curves. Primary outcomes included cardiogenic shock (CS) and mortality. Among 4818 patients with AHF, 1143 had an SI ≥0.9. Compared with SI <0.9, patients with high SI were more likely males, younger, and having advanced New York Heart Association class, fewer cardiovascular risk factors and less prehospital β-blockers and angiotensin-converting enzyme inhibitor use. Shock index had significant negative correlations with age, pulse pressure, mean arterial pressure, and left ventricle ejection fraction and had positive correlation with hospital length of stay. Shock index ≥0.9 was significantly associated with higher composite end points, in-hospital, and 3-month mortality. Shock index ≥0.9 had 96% negative predictive value (NPV) and 3.5 relative risk for mortality. Multivariate regression analysis showed that SI was independent predictor of mortality and CS. With a high NPV, SI is a simple reliable bedside tool for risk stratification of patients with AHF. However, this conclusion needs further support.