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Re: Is “Ischemia Modified Albumin” an early diagnostic indicator of myocardial infarction?

Dear Editor,

I would like to thank Dr Collinson (1) for his article about the utility of ischemia modified albumin (IMA) in chest pain patients. However the results may be overstated regarding IMA in patients with chest pain, particularly in patients with acute myocardial infarction (AMI).

First of all excluding ST segment elevation MI patients could create a selection bias. Because some of these patients have normal cardiac troponin (cTn) levels initially although they have a diagnostic ECG for ST segment elevation myocardial infarction.

The second point to emphasize is the negative predictive value of both a negative cardiac troponin and IMA was stated as %100. However the contribution of IMA to this rate is minimal because IMA was positive in only two acute myocardial infarction patients with a negative cTn (2/37). So it seems that cTn was able to exclude the great majority of AMI patients. And also a negative test might not be able to allow exclude AMI because 19 patients had a positive cTn without a positive IMA (19/37). And also the suggestion in the discussion section that a positive IMA alone will need a follow up to confirm AMI may be controversial. Because of the 342 study participants with a positive IMA, only two of them were AMI as well as a negative cTn (2/342). It seems IMA contributes little to cTn in diagnosing AMI.

As it is known, cardiac troponins have a high sensitivity and specificity in diagnosing AMI, however these high sensitivity and specificity decline in the early hours of the symptoms onset. The critical question here is “How much IMA adds in diagnosing AMI in the early hours of symptoms onset to cTn, ECG, likelihood or risk stratifications made by different societies and the coagulation and inflammation markers studied so far like d-dimer, C-reactive protein and IL-6?”. As it was mentioned in the manuscript, the median time of symptoms onset was 6 hours in the study population. These findings do not inform us about the utility of IMA in the early hours of AMI which was the most critical challenge. Furthermore 37 AMI patients as a pathologic group may be too small to make suggestions for the diagnosing power of IMA in AMI.

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