Microalbuminuria is an early response following acute myocardial infarction.

Ninety-six patients admitted to two coronary care units with suspected acute myocardial infarction were studied. The diagnosis was confirmed in 44, the remaining 52 were used as a control group. The first urine passed after admission, together with early morning urines on the following 3 days, were saved in all patients. Urinary albumin and IgG were measured by automated immunoturbidimetry and expressed as the protein creatinine ratio in mg.mmol-1. The log mean (SD) albumin creatinine ratios for the first urine passed in the myocardial infarction and non-myocardial infarction patient groups were 6.2(4.2) and 1.3(3.4) respectively. The difference in log mean albumin creatinine ratio was 4.9 mg.mmol-1, 95% CI 3.4 to 6.2 mg.mmol-1; t = 6.127 df = 94, P less than 0.0001. The median IgG creatinine ratio for the first urine passed after admission in myocardial infarction patients was 1.0 mg.mmol-1 (95% CI 0.5 to 1.2) and for non-myocardial infarction patients 0.3 (95% CI 0.2 to 0.4). Increased urinary protein excretion appears to be an early and proportional response to acute myocardial infarction.