Risk factors for 24-hour progression to cardiogenic shock in acute coronary syndrome presenting with pre-shock state

Background Among patients with acute coronary syndrome (ACS) presenting in a pre-shock state, a subset deteriorates to cardiogenic shock within 24 hours (“delayed shock”). Purpose To identify predictors of delayed shock progression and to derive a clinically applicable risk score. Methods We conducted a single-center retrospective study of consecutive ACS patients who underwent percutaneous coronary intervention (PCI) between 2021 and 2025 (n=336). Patients presenting with SCAI stage A or B at hospital arrival were included. We excluded patients who underwent PCI more than 24 hours after arrival and those with procedure-related complications. Patients who progressed to SCAI stage C–E within 24 hours were classified as the Worsened group, while those who remained at SCAI stage A–B were classified as the Stable group (Figure 1). A final age- and sex-adjusted model was constructed using Firth penalized logistic regression. A point-based risk score was derived from the regression coefficients. Model discrimination was assessed using the area under the receiver operating characteristic curve (AUC). Internal validation was performed with 500 bootstrap resamples to estimate the optimism-corrected AUC. Results Among 336 patients, 240 presented with SCAI stage A or B at hospital arrival. Of these, 32 patients progressed to SCAI stage C–E within 24 hours (Worsened group, n = 32; Stable group, n = 208). The median age was 76 years in the Worsened group versus 71 years in the Stable group, and 65.6% (21/32) were male in the Worsened group versus 70.2% (146/208) in the Stable group. ST-segment elevation myocardial infarction (STEMI) was present in 78.1% (25/32) of the Worsened group and 62.0% (129/208) of the Stable group (p = 0.116), Killip class II or III was observed in 25.0% (8/32) versus 4.8% (10/208), respectively. In-hospital mortality was significantly higher in the Worsened group compared with the Stable group (28.1% [9/32] vs. 0.5% [1/208], log-rank p < 0.001), and was comparable to that of patients presenting with cardiogenic shock at hospital arrival (33.3% [10/30]). Based on the Firth penalized logistic regression model, the derived risk score assigned 1 point for STEMI, 2 points for Killip class II or III, and 3 points each for multivessel disease and heart rate ≥100 bpm (Figure 3). The apparent AUC was 0.764; the optimism-corrected AUC after 500 bootstrap resamples was 0.763 (optimism = 0.001). Higher scores were significantly associated with delayed shock progression (Figure 4). Conclusion In ACS patients presenting with SCAI stage A–B, progression to SCAI stage C–E within 24 hours was associated with markedly worse in-hospital survival, comparable to patients presenting with overt cardiogenic shock. A simple four-variable risk score demonstrated good discriminative ability and may facilitate early risk stratification for delayed shock.