Accuracy of Physicians in Differentiating Type 1 and Type 2 Myocardial Infarction Based on Clinical Information

Background: Physicians commonly judge whether a myocardial infarction (MI) is type 1 (thrombotic) vs type 2 (supply/demand mismatch) based on clinical information. Little is known about the accuracy of physicians’ clinical judgement in this regard. We aimed to determine the accuracy of physicians’ judgement in the classification of type 1 vs type 2 MI in perioperative and nonoperative settings. Methods: We performed an online survey using cases from the Optical Coherence Tomographic Imaging of Thrombus (OPTIMUS) Study, which investigated the prevalence of a culprit lesion thrombus based on intracoronary optical coherence tomography (OCT) in patients experiencing MI. Four MI cases, 2 perioperative and 2 nonoperative, were selected randomly, stratified by etiology. Physicians were provided with the patient's medical history, laboratory parameters, and electrocardiograms. Physicians did not have access to intracoronary OCT results. The primary outcome was the accuracy of physicians' judgement of MI etiology, measured as raw agreement between physicians and intracoronary OCT findings. Fleiss’ kappa and Gwet's AC1 were calculated to correct for chance. Results: The response rate was 57% (308 of 536). Respondents were 62% male; median age was 45 years (standard deviation ± 11); 45% had been in practice for > 15 years. Respondents’ overall accuracy for MI etiology was 60% (95% confidence interval [CI] 57%-63%), including 63% (95% CI 60%-68%) for nonoperative cases, and 56% (95% CI 52%-60%) for perioperative cases. Overall chance-corrected agreement was poor (kappa = 0.05), consistent across specialties and clinical scenarios. Conclusions: Physician accuracy in determining MI etiology based on clinical information is poor. Physicians should consider results from other testing, such as invasive coronary angiography, when determining MI etiology.