Predicting cardiac outcomes

Despite substantial advances in the diagnosis of suspected acute coronary syndromes, significant challenges persist.1 Andrew Worster and colleagues recently reported in CMAJ that ischemia-modified albumin (IMA) was a poor predictor of cardiac outcomes in patients with potential cardiac ischemia symptoms.2 The authors tested 2 thresholds for IMA: 85 μ/mL, as suggested by the manufacturer, and 80 μ/mL. It is important to point out, however, that IMA levels vary considerably, even among healthy individuals. Taking these variations into account may improve the predictive characteristics of IMA.

We examined 35 healthy men (age range 25–54 years) recruited from the general public who had not had a myocardial infarction. Using standard laboratory techniques we found that the average resting IMA concentration was 94 μ/mL (97.5% confidence interval 84–104 μ/mL). IMA concentration was significantly and inversely correlated with serum albumin but not with creatinine concentration. Serum IMA concentration was also significantly associated with serum lactate concentration.3 Taking these and other known factors into account may improve the utility of IMA in predicting serious cardiac outcomes.