Admission Shock Index Is an Independent Predictor of In‐Hospital All‐Cause Mortality in Patients With Acute Aortic Dissection and Intramural Hematoma

BACKGROUND: Acute aortic dissection (AD) and intramural hematoma (IMH) are associated with high mortality, necessitating reliable early risk prediction. The shock index (SI) is a potential prognostic marker in critical care, but its value in AD/IMH remains unclear. This study evaluated the association between admission SI and in-hospital all-cause mortality. METHODS: This single-center retrospective cohort study included 1250 patients with acute AD/IMH, stratified by an optimal SI cut-off of 0.6 determined by ROC analysis. Kaplan-Meier curves and Cox proportional hazards models were used to assess the relationship. Subgroup analyses were also conducted to confirm the consistency of the main findings. RESULTS: The 30-day cumulative in-hospital all-cause mortality was significantly higher in the SI ≥ 0.6 group than in the SI < 0.6 group (Total: 25.7% vs. 14.4%, p < 0.001; Stanford A: 35.5% vs. 25.2%, p < 0.001; Stanford B: 13.4% vs. 4.8%, p < 0.001). An SI ≥ 0.6 was independently associated with increased in-hospital mortality (adjusted hazard ratio (aHR) 1.67, p = 0.004), consistent across Stanford A (aHR 1.52, p = 0.038) and Stanford B (aHR 2.57, p = 0.014) subgroups. Furthermore, the association was stronger among patients managed without surgery or thoracic endovascular aortic repair (TEVAR) (Total: aHR 2.02, p < 0.001; Stanford A: aHR 1.77, p = 0.009; Stanford B: aHR 3.30, p = 0.004). CONCLUSION: An admission SI ≥ 0.6 is independently associated with increased in-hospital all-cause mortality in acute AD/IMH, particularly among those managed without surgery/TEVAR. Admission SI may serve as a simple, rapid, and valuable tool for early clinical risk stratification.