Selection of study population. In 53 out of 820 patients, CAG was not followed by PCI. Of these patients, 34 were treated with emergency or elective CABG or with conservative therapy, leaving 19 patients with a final diagnosis other than STEMI. CAG=coronary angiography, STEMI=ST-segment elevation myocardial infarction, PCI=percutaneous coronary intervention, CABG=coronary artery bypass grafting, CAD=coronary artery disease.