Coronary Artery Disease Without Standard Cardiovascular Risk Factors

Recently, one observational study showed that patients with ST-segment elevation myocardial infarction (STEMI) without standard cardiovascular risk factors were associated with increased mortality compared with patients with risk factors. This unexpected result should be evaluated in other populations including those with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and chronic coronary syndrome (CCS). Among 30,098 consecutive patients undergoing first coronary revascularization in the CREDO-Kyoto PCI/CABG (Coronary Revascularization Demonstrating Outcome Study in Kyoto Percutaneous Coronary Intervention/Coronary Artery Bypass Grafting) registry cohort-2 and 3, we compared clinical characteristics and outcomes between patients with and without risk factors stratified by their presentation (STEMI n = 8,312, NSTE-ACS n = 3,386, and CCS n = 18,400). Patients with risk factors were defined as having at least one of the following risk factors: hypertension, dyslipidemia, diabetes, and current smoking. The proportion of patients without risk factors was low (STEMI: 369 patients [4.4%], NSTE-ACS: 110 patients [3.2%], and CCS: 462 patients [2.5%]). Patients without risk factors compared with those with risk factors more often had advanced age, low body weight, and malignancy and less often had history of atherosclerotic disease and prescription of optimal medical therapy. In patients with STEMI, patients without risk factors compared with those with risk factors were more often women and more often had atrial fibrillation, long door-to-balloon time, and severe hemodynamic compromise. During a median of 5.6 years follow-up, patients without risk factors compared with those with risk factors had higher crude incidence of all-cause death. After adjusting confounders, the mortality risk was significant in patients with CCS (hazard ratio [HR] 1.22, 95% confidence interval [CI] 1.01 to 1.49, p = 0.04) but not in patients with STEMI (HR 1.06, 95% CI 0.89 to 1.27, p = 0.52) and NSTE-ACS (HR 1.07, 95% CI, 0.74 to 1.54, p = 0.73). In conclusion, among patients undergoing coronary revascularization, patients without standard cardiovascular risk factors had higher crude incidence of all-cause death compared with those with at least one risk factor. After adjusting confounders, the mortality risk was significant in patients with CCS but not in patients with STEMI and NSTE-ACS.