When compared with fibrinolysis, primary percutaneous coronary intervention (PCI) has been associated with significant reductions in morbidity and mortality and decreases risks for mechanical and arrhythmic complications in patients presenting with ST elevation myocardial infarctions (STEMI). “As outcomes have improved with primary PCI, there has been increasing interest in further stratifying risk for patients presenting with STEMI,” says Ryan S. Wilson, MD. There is also interest in identifying patients at highest risk for complications and death.

Further Validating the CADILLAC Risk Score

One of several scoring systems developed to further stratify risk in patients with STEMI is the CADILLAC risk score. CADILLAC evaluates a number of prognostic variables, including left ventricular ejection fraction, creatinine clearance, Killip class, final TIMI flow, age, anemia, and the presence of three-vessel disease. Using the CADILLAC risk score, patients are classified into low-, intermediate-, and high-risk groups. CADILLAC scores of 0 to 2 are low risk and scores of 3 to 5 are intermediate risk, whereas scores of 6 or higher indicate high risk (Table).

Previous research has shown that low CADILLAC risk scores correlate with fewer adverse events and lower mortality rates in patients presenting with STEMI, but not in those with cardiac arrest or in need of mechanical support. For a new study published in BMC Cardiovascular Disorders, Dr. Wilson and colleagues aimed to further validate the CADILLAC risk score in patients presenting with STEMI, but who did not have cardiac arrest or cardiogenic shock and did not require mechanical support on admission. They also sought to determine the ability of CADILLAC to risk stratify patients with STEMI during their index hospitalization and for up to 1 year following their initial presentation.

CADILLAC Scores Provide Prognostic Utility

For the study, researchers reviewed data on 341 STEMI hospitalizations among patients treated with primary PCI from 2014-2018. Patients were stratified using the CADILLAC risk score. Results showed that adverse clinical event rates were similar for patients with intermediate risk during hospitalization (OR, 1.23) and at 30 days (OR, 2.27). Adverse clinical event rates were significantly higher in patients classified as high risk by CADILLAC during their hospitalization (OR, 4.75) and at 30 days (OR, 8.73). At the 1-year follow-up, cumulative adverse event rates were significantly higher for patients classified as high risk (58.6%) or intermediate risk (22.9%) than for low-risk patients (9.4%).

The authors noted that CADILLAC was originally developed to identify patients at low risk for adverse cardiovascular events following STEMI that was treated with primary PCI. In the new study, patients with a low CADILLAC risk score had fewer cardiovascular risk factors, no incidence of chronic kidney disease, and predominantly presented with Killip class I symptoms. These patients also had a normal ejection fraction after revascularization, were less likely to have left anterior descending artery vessel as the culprit lesion and were less likely to have multi-vessel coronary artery disease. The mortality rate was 0% for patients defined as low risk by CADILLAC during hospitalization and for up to 1 year follow up.

Can CADILLAC Improve Care for Uncomplicated Patients?

Scoring systems like the CADILLAC risk score may have an important clinical impact on patients presenting with STEMI, according to Dr. Wilson. “Our study further validates the CADILLAC risk score and its prognostic utility in identifying patients at low risk for adverse clinical events following STEMI,” he says. The study group noted that CADILLAC may help clinicians determine if all patients require the same level and duration of hospital care after they are revascularized. They reported that it may be possible for patients with an uncomplicated low-risk STEMI to be safely discharged early from the hospital or to not require ICU monitoring. However, they caution that more research is needed to address this clinically critical question.