Limitations of risk score models in patients with acute chest pain

Abstract

Objectives: Cardiac multidetector computed tomography (CMCT) has potential to be used as a screening test for patients with acute chest pain, but several tools are already used to risk-stratify this population. Risk models exist that stratify need for intensive care (Goldman), short-term prognosis (Thrombolysis in Myocardial Infarction, TIMI), and 1-year events (Sanchis). We applied these cardiovascular risk models to candidates for CMCT and assessed sensitivity for prediction of in-hospital acute coronary syndrome (ACS). We hypothesized that none of the models would achieve a sensitivity of 90% or greater, thereby justifying use of CMCT in patients with acute chest pain.

Methods: We analyzed TIMI, Goldman, and Sanchis in 148 consecutive patients with chest pain, nondiagnostic electrocardiogram, and negative initial cardiac biomarkers who previously met inclusion and exclusion criteria for the Rule-Out Myocardial Infarction Using Coronary Artery Tomography Study. ACS was adjudicated, and risk scores were categorized based on established criteria. Risk score agreement was assessed with weighted kappa statistics.

Results: Overall, 17 (11%) of 148 patients had ACS. For all risk models, sensitivity was poor (range, 35%-53%), and 95% confidence intervals did not cross above 77%. Agreement to risk-classify patients was poor to moderate (weighted kappa range, 0.18-0.43). Patients categorized as "low risk" had nonzero rates of ACS using all 3 scoring models (range, 8%-9%).

Conclusions: Available risk scores had poor sensitivity to detect ACS in patients with acute chest pain. Because of the small number of patients in this data set, these findings require confirmation in larger studies.

Figures

Figure 1. Goldman Risk Score Algorithm

The Goldman Risk Score categorizes patients into discrete risk groups based on risk of major adverse cardiac events (dysrhythmia, pump failure, or ischemia) within 72 hours of initial presentation. Goldman risk factors included systolic blood pressure below 110 mm Hg, bilateral rales heard above the bases on physical examination, and known unstable ischemic heart disease (defined as a worsening of previously stable angina, a new onset of angina, or pain that was the same as previous myocardial infarction). The derivation and validation of the above protocol are from Goldman et al.,– and adapted with permission. Because patients enrolled in ROMICAT had nondiagnostic ECGs, there were no patients classified as “High Risk” in this study, leaving 3 Goldman risk categories (Very Low, Low, and Intermediate) for analysis. For consistency with TIMI and Sanchis, we use the nomenclature of Low (“Very Low” in figure), Intermediate (“Low” in figure), and High (“Intermediate” in figure) to refer to these three Goldman categories in the text. Abbreviations: AMI = acute myocardial infarction, ECG = electrocardiogram, RF = Goldman risk factor.