A severity scoring system for risk assessment of patients with cardiogenic shock: a report from the SHOCK Trial and Registry

Abstract

Background: Early revascularization (ERV) is beneficial in the management of cardiogenic shock (CS) complicating myocardial infarction. The severity of CS varies widely, and identification of independent risk factors for outcome is needed. The effect of ERV on mortality in different risk strata is also unknown. We created a severity scoring system for CS and used it to examine the potential benefit of ERV in different risk strata using data from the SHOCK Trial and Registry.

Methods: Data from 1,217 patients (294 from the randomized trial and 923 from the registry) with CS due to pump failure were included in a Stage 1 severity scoring system using clinical variables. A Stage 2 scoring system was developed using data from 872 patients who had invasive hemodynamic measurements. The outcome was in-hospital mortality at 30 days.

Results: In-hospital mortality at 30 days was 57%. Multivariable modeling identified 8 risk factors (Stage 1): age, shock on admission, clinical evidence of end-organ hypoperfusion, anoxic brain damage, systolic blood pressure, prior coronary artery bypass grafting, noninferior myocardial infarction, and creatinine > or = 1.9 mg/dL (c-statistic = 0.74). Mortality ranged from 22% to 88% by score category. The ERV benefit was greatest in moderate- to high-risk patients (P = .02). The Stage 2 model based on patients with pulmonary artery catheterization included age, end-organ hypoperfusion, anoxic brain damage, stroke work, and left ventricular ejection fraction <28% (c-statistic = 0.76). In this cohort, the effect of ERV did not vary by risk stratum.

Conclusions: Simple clinical predictors provide good discrimination of mortality risk in CS complicating myocardial infarction. Early revascularization is associated with improved survival across a broad range of risk strata.

Trial registration: ClinicalTrials.gov NCT00000552.

Figure 1

Risk Factor Profile by Stage I Clinical Severity Score Category. Y-axis represents percentage of total sample.

Figure 2

Thirty-day mortality by Stage I clinical severity score quantile and revascularization status. Early revascularization is defined as ≤18 hours of shock diagnosis. Estimates based on one imputation dataset.