Results
Myocardial infarction (MI) was defined based on Universal Definition of Myocardial Infarction.13 Coronary revascularization was defined as angioplasty with or without stent placement or coronary artery bypass surgery.14 Percutaneous coronary intervention (PCI) was defined as any therapeutic catheter intervention in the coronary arteries. Coronary artery bypass graft (CABG) surgery was defined as any cardiac surgery in which coronary arteries were operated on.
The primary outcomes in this study were the (1) risk stratification of chest pain patients into low-risk, intermediate-risk, and high-risk categories; (2) incidence of a MACE within 6 weeks of initial presentation. MACE consists of acute myocardial infarction (AMI), PCI, CABG, coronary angiography revealing procedurally correctable stenosis managed conservatively, and death due to any cause.
Our secondary outcomes were discharge or death due to any cause within 6 weeks after presentation.
Follow-up
Within 6 weeks after presentation to the ED, a follow-up phone call was placed to assess the patient’s progress. The follow-up focused on the endpoint of MACE, comprising all-cause death, MI, and revascularization. No patient was lost to follow-up.
Statistical analysis
We aimed to find a difference in the 6-week MACE between low-, intermediate-, and high-risk categories of the HEART score. The prevalence of CHD in India is 10%,4 and assuming an α of 0.05, we needed a sample of 141 patients from the ED patient population. Continuous variables were presented by mean (SD), and categorical variables as percentages. We used t test and the Mann-Whitney U test for comparison of means for continuous variables, χ2 for categorical variables, and Fisher’s exact test for comparison of the categorical variables. Results with P < .05 were considered statistically significant.