How are ischemia modified albumin (IMA) cardiac markers characterized and what do they indicate?

Updated: Nov 20, 2018
  • Author: Donald Schreiber, MD, CM; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Answer

Ischemia modified albumin (IMA) is a novel marker of ischemia that is produced when circulating serum albumin contacts ischemic heart tissues. IMA can be measured by the albumin cobalt binding assay that is based on IMA’s inability to bind to cobalt. [61] A rapid assay with a 30-minute laboratory turnaround time has been developed and marketed as the first commercially available US Food and Drug Administration (FDA)–approved marker of myocardial ischemia.

Based on investigations of myocardial ischemia induced by balloon inflation during percutaneous coronary intervention, IMA levels rise within minutes of transient ischemia, peak within 6 hours, and can remain elevated for as long as 12 hours.

Studies on the use of IMA in patients with chest pain in the ED found sensitivities that ranged from 71-98% and specificities of 45-65%, with a negative predictive value of 90-97% for ACS. [62]

A multimarker approach in one study, using a combination of ECG findings, TnT levels, and IMA levels, achieved a sensitivity of 95% for ACS, [63] while a second study calculated that the combination of IMA, myoglobin, CK-MB, and TnI increased the sensitivity to 97% for detecting myocardial ischemia. [64]

However, IMA levels are also elevated in patients with cirrhosis, certain infections, and advanced cancer, which reduces the specificity of the assay. Further validation and outcome studies are required to evaluate IMA’s use in the ED diagnosis of ACS when the ECG and cardiac troponins levels are nondiagnostic.


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