Introduction: Recent studies showed that patients without standard modifiable cardiovascular risk factors (CVRFs) suffering an acute myocardial infarction (AMI) might have worse outcomes and prognoses than patients with established CVRFs (1). The goal of the present study was to determine the proportion and relevant characteristics of patients with no apparent CVRFs who present with AMI at a tertiary-level clinical center.

Patients and Methods: We grouped and analyzed a cohort of consecutive patients admitted for AMI to our center during the 2019-2020 period. We examined the presence or absence of apparent CVRFs including smoking, arterial hypertension, diabetes mellitus, history of myocardial infarction or revascularization, and atrial fibrillation.

Results: The proportion of patients with AMI and without apparent CVRFs in our sample was 14.4% (29/202 patients). The rate of composite outcome consisting of in-hospital death and emergent referral to coronary artery bypass graft surgery was lower in patients without than with CVRFs (3.4% vs. 8.7%). Both groups had a similar prevalence of multivessel coronary disease (17.2% vs. 23.1%). Furthermore, they were less likely to present with dyspnea or nausea and vomiting, compared to patients with CVRFs (13.8 vs. 27.7% and 17.2 vs. 33.5%, respectively). Notably, both groups did not significantly differ in terms of age (median 67 vs. 65 years), male sex (62.1 vs. 68.8%), AMI type (ST-elevation myocardial infarction in 66 vs. 58% of cases), hemoglobin (median 139 vs. 141 g/L), renal function (median creatinine of 74 vs. 79 μmol/L), and C-reactive protein (median 6.1 vs. 5.0 mg/L). However, patients without apparent CVRFs exhibited a significantly greater degree of myocardial injury as evidenced by higher median high-sensitivity cardiac troponin I levels, compared to patients with at least one CVRF [1073 (IQR 156-7000) vs. 300 (IQR 65-3551) ng/L, p<0.05] as shown in Figure 1.

Conclusion: About 14 in 100 patients with AMI in our cohort did not have apparent CVRFs. These patients seem to be less likely to present with dyspnea or nausea and vomiting and do not differ significantly in most of the clinical and laboratory variables to patients with CVRFs. However, these patients had more than a 3-fold greater myocardial injury as measured by circulating troponin levels. Therefore, clinical scrutiny should be applied to patients without overt symptoms and a history of CVRFs that present to emergency department with chest pain.