Does shock index provide prognostic information in acute heart failure?

Decoding cardiogenic shock: assessing shock index and its variants as prognostic indicators for in-hospital mortality

BACKGROUND

Cardiogenic shock (CS) is associated with high in-hospital mortality. Objective assessment of its severity and prognosis is paramount for timely therapeutic interventions. This study aimed to evaluate the efficacy of the shock index (SI) and its variants as prognostic indicators for in-hospital mortality.

METHODS

A retrospective study involving 1282 CS patients were evaluated. Baseline patient characteristics, clinical trajectory, hospital outcomes, and shock indices were collected and analysed. Receiver operating characteristic (ROC) curves were employed to determine the predictive accuracy of shock indices in predicting in-hospital mortality.

RESULTS

Of those evaluated, 866 (67.6%) survived until discharge. Non-survivors were older (66.0 ± 13.7 vs. 57.4 ± 16.2, P < 0.001), had a higher incidence of cardiac risk factors, and were more likely to present with acute coronary syndrome (33.4% vs. 16.1%, P < 0.001) and out-of-hospital cardiac arrest (11.3% vs. 5.3%, P < 0.001). All mean shock indices were significantly higher in non-survivors compared with survivors. ROC curves demonstrated that adjusted shock index (ASI), age-modified shock index (AMSI), and shock index-C (SIC) had the highest predictive accuracy for in-hospital mortality, with AUC values of 0.654, 0.667, and 0.659, respectively. Subgroup analysis revealed that SIC had good predictive ability in patients with STEMI (AUC: 0.714) and ACS (AUC: 0.696) while AMSI and ASI were notably predictive in the OHCA group (AUC: 0.707 and 0.701, respectively).

CONCLUSIONS

Shock index and its variants, especially ASI, AMSI, and SIC, may be helpful in predicting in-hospital mortality in CS patients. Their application could guide clinicians in upfront risk stratification. SIC, ASI, and AMSI show potential in predicting in-hospital mortality in specific CS subsets (STEMI and OHCA). This is the first study to evaluate SI and its variants in CS patients.

Prognostic utility of shock index and modified shock index on long-term mortality in acute decompensated heart failure; Persian Registry of cardioVascular diseasE/Heart Failure (PROVE/HF) study

BACKGROUND

Shock index (SI) and modified SI (MSI) are used for prognosis in patients with cardiovascular diseases (CVDs), especially myocardial infarction. However, the utility of these indices in heart failure(HF) is less frequently investigated. We aimed to evaluate the long-term prognostic capability of SI and MSI among Iranian HF patients.

METHODS

This retrospective cohort study was implemented in the context of the Persian Registry Of cardioVascular diseasE/HF (PROVE/HF). A total of 3896 acute decompensated HF (ADHF) patients were enrolled from March 2016 to March 2020. SI and MSI were assessed at admission. Receiver operating characteristic (ROC) and Kaplan-Meier curves were used to define optimum SI and MSI cut-off points and depict mortality during follow-up, respectively. The association of CVD death according to different SI and MSI cut-off points and quartiles was assessed through univariate and multivariate regression hazard models.

RESULTS

Mean age of participants was 70.22 ± 12.65 years (males: 62.1%). We found 0.66 (sensitivity:62%, specificity: 51%) and 0.87 (sensitivity: 61%, specificity: 51%) as optimised cut-off points for SI and MSI, respectively. Mean follow-up was 10.26 ± 7.5 months and 1110 (28.5%) deaths occurred during this time. Multivariate adjusted models revealed patients had SI ≥ 0.66 or within the third and fourth quartiles had higher likelihood of mortality compared to reference group (hazard ratio(HR): 1.58, 95%CI: 1.39-1.80, p < 0.001, HR: 1.38,95%CI:1.14-1.66, p = 0.001 and HR:2.00,95%CI:1.68-2.38, p < 0.001, respectively). MSI outcomes were similar (MSI ≥ 0.87: HR: 1.52,95%CI: 1.34-1.72, p < 0.001, third quartile (0.89 ≤ MSI < 1.00):HR:1.23,95%CI:1.009-1.50, p = 0.041, fourth quartile (MSI ≥ 1.00): HR: 1.80,95%CI: 1.53-2.13, p < 0.001). Kaplan-Meier curves showed patients with higher SI and MSI cut-off values and quartiles had lower survival rates.

CONCLUSION

Higher SI and MSI values were associated with increased mortality risk, and these two bedside indices could be appropriately considered for long-term prognosis in ADHF patients.

In-hospital mortality of acute pulmonary embolism: Predictive value of shock index, modified shock index, and age shock index scores

OBJECTIVE

The shock index (SI), modified shock index (MSI), and age shock index (ASI) have been reported to predict adverse outcomes in patients with different acute cardiovascular conditions. This study aimed to investigate the association between these indexes and in-hospital mortality in patients with acute pulmonary embolism.

METHODS

The medical records of all adult patients who were hospitalized with acute pulmonary embolism between June 2014 and June 2019, were examined. Collected data included vital signs, demographic characteristics, comorbidities, and laboratory values on presentation. The predictive value of SI, MSI, ASI, and pulmonary embolism severity index (PESI) for predicting in-hospital mortality were compared by C-statistics.

RESULTS

A total of 602 consecutive patients (mean age 66.7±13.2 years, 55% female) were included, and 62 (10.3%) of the patients died during their in-hospital course. The admission SI, MSI, ASI, and PESI were significantly higher in the deceased patients. After adjusting for other factors, the SI, MSI, PESI, and ASI were independent predictors of in-hospital mortality. The prognostic performance of ASI (C-statistics 0.74) was better than MSI (C-statistics 0.71), SI (C-statistics 0.68), and PESI (C-statistics 0.65).

CONCLUSION

The ASI may be used to identify patients at risk for in-hospital mortality following acute pulmonary embolism.

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.