The unexpected silent manifestation of myocardial infarctions in ischemic heart failure patients: Insights from a case-control study.

Background: Recent studies show Silent Myocardial Infarction (SMI) as a quite frequent event. However, regarding severe tertiary care patients that frequently present consequences of Coronary Artery Disease (CAD) and Left Ventricular Dysfunction (LVD), the occurrence of this manifestation is unexpected and its associated factors aren't clear in the literature.

Aim: To compare clinical, laboratorial, ventricular and angiographic factors between silent and classical presentation of MI in patients with CAD and LVD.

Methods: Patients with multivessel CAD with over 70 % obstructive lesions and LVD with EF less than 35 % were evaluated for MASS VI trial and later included in the present study. The ventricular function and coronary assessment were measured by echocardiography and SYNTAX score, respectively. The population was stratified in a SMI group and Clinically Manifested Myocardial Infarction (CMMI) group based on MI presentation for a comparison of medical parameters.

Results: From 132 patients, 47 (35.6 %) were classified as SMI and 85 (64.4 %) as CMMI. No differences were observed between groups regarding age, sex, diabetes mellitus, SYNTAX score, or collateral circulation. Higher proportion of NYHA II classification, inferior wall MI and lower creatinine clearance were found in SMI group. After multivariate analysis, peripheral diabetic neuropathy (OR = 4.6 [1.1‒12.7] p = 0.032) and inferior wall MI (OR = 4.1 [1.5‒11.4] p = 0.007) were significantly associated with SMI.

Conclusion: Peripheral diabetic neuropathy and inferior wall MI were associated with SMI presentation. Overall, associated factors tend to be similar comparing SMI and CMMI, but in the specific population of diabetic patients with chronic neuropathy a special care should be taken.