[show abstract][hide abstract] ABSTRACT: BACKGROUND: To assess the relationship between serial serum leptin levels in patients with acute myocardial infarction (AMI) who received thrombolysis and the degree of coronary atherosclerosis, coronary reperfusion, echocardiographic findings, and clinical outcome. 51 consecutive patients presenting with AMI were studied. Clinical characteristics including age, sex, body mass index (BMI) and cardiovascular risk factors were recorded. Serial serum leptin levels at the time of admission and subsequently at 0, 6, 12, 24, 36, 60 hours afterwards were obtained. Coronary angiography was performed in 34 patients; the relation between serum leptin levels and evidence of coronary reperfusion as well as the extent of coronary atherosclerosis according to the coronary artery surgery study classification (CASS) were evaluated. Echocardiographic evaluation was performed in all patients. 36 matched patients were enrolled as control group who had serum leptin level 9.4 +/- 6.5 ng/ml. RESULTS: The patients mean age was 50.5 +/- 10.6 years. There were 47 males and 3 females. 37.1% were diabetics, 23.5% were hypertensive, 21.6% were dyslipidemic and 22.7% were obese (BMI [greater than or equal to] 30). Leptin concentrations (ng/ml) increased and peaked at the 4th sample (36 hrs) after admission (mean +/- SD) sample (1) =9.55 +/- 7.4, sample (2) =12.9 +/- 8.4, sample (3) =13.8 +/- 10.4, sample (4) =18.9 +/- 18.1, sample (5) =11.4 +/- 6.5, sample (6) =10.8 +/- 8.9 ng/ml. There was a significant correlation between serum leptin and BMI (r = 0.342; p =0.03). Leptin levels correlated significantly to creatine kinase level on the second day (r = 0.43, p [less than or equal to] 0.01). Significant correlation of mean serum leptin with the ejection fraction (P < 0.05) was found. No difference in timing of peak serum leptin between patients who achieved coronary reperfusion vs. those who did not (p= 0.8). There was a trend for an increase in the mean serum leptin levels with increasing number of diseased vessels. There was no correlation between serum leptin levels and outcome neither during the hospitalization nor at 9 months follow up. CONCLUSION: Serum leptin levels increase after myocardial infarction. Serum leptin level may be a predictor of the left ventricular ejection fraction and the degree of atherosclerosis but not of coronary reperfusion.