<![CDATA[Background: Cardiovascular disease is a leading cause of global mortality, with Indonesia ranking third in the highest cardiovascular deaths. Acute myocardial infarction, divided into STEMI and NSTEMI, is part of the acute coronary syndrome due to total occlusion of coronary arteries requiring immediate revascularization. Diabetes Mellitus reduces endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) production, leading to endothelial dysfunction and an increased risk of vascular disease. DM-related endothelial dysfunction affects vascular relaxation and the formation of atherosclerotic plaques as well as thrombi in ST-elevation myocardial infarction (STEMI). Methods: This research was an analytical observational study with a cross-sectional approach, using normality tests and the Mann-Whitney U Test. The research sample was collected using consecutive sampling techniques and obtained from the medical records of 72 confirmed STEMI patients, with and without comorbid Diabetes Mellitus. Results: The research results indicated that the majority of patients were in the age range of 60-69 years (52.7%), male (86.1%), with a Body Mass Index (BMI) of 23-24.9 (45.8%), comorbid hypertension (52.7%), and a history of smoking (72.3%). The mean eNOS level in the control group was Median eNOS 38,839 U/mL with maximum level 584,762 U/ml and minimum 17,024 U/ml. Median eNOS level in the test group was 36,077 U/mL with the maximum level 679,754 U/ml and minimum 1,836 U/ml. Conclusions: There was no significant difference in eNOS levels between the two groups (Sig (2-Tailed) > 0.05).]]>
