Post-mortem Gross Detection of Early Myocardial Infarction using Triphenyl Tetrazolium Chloride Test

Abstract

Background: Ischemic heart disease is the leading cause of mortality in the world. More than 17 million
people die each year as a result of myocardial infarctions. Post-mortem histochemical detection of early
myocardial infarction using 2,3,5-Triphenyl Tetrazolium Chloride (TTC) technique is based on the fact
that ischemic myocardial cells lose their membrane integrity and release dehydrogenase enzyme into the
blood stream, resulting in decrease or total depletion of these enzymes within the necrotic areas of the
myocardium, and so, after immersion in TTC solution, enzyme depleted necrotic myocardium will not
retain TTC dye and therefore appears as pale/yellow areas. Materials and Methods: This prospective
postmortem study was conducted at Medicolegal Directorate in Baghdad city during the period from
March 2020 to December 2020. Myocardial specimens were isolated from 75 cases of sudden natural death
and were subjected to 1% TTC solution staining for gross assessment, and subsequently, tissue samples were
taken from suspected areas, processed and stained with H&E for histopathological evaluation and detection
of a possible acute myocardial infarction. Results: The mean age of studied cases was 50.3 ±12.57 years,
ranging from 18 to 78 years, median age was 53 years. Males constituted the majority of cases (80%). Cases
were predominantly within 40-59 years age group (58%). The postmortem interval was ranging from 2 to
17 hours (mean= 8.6 ±3.6 hours). After immersion in 1% TTC solution, 45 myocardial specimens showed
macroscopic pale/yellow areas which were indicative of acute myocardial infarcts within the ventricular
wall, while histopathological examination of specimens revealed features of acute myocardial infarction
(AMI) in 62 specimens. TTC stain was found to have a diagnostic sensitivity of 69.4% and specificity of
76.9% in postmortem detection of AMI. Conclusion: The TTC technique allows identification of early
myocardial necrosis. It’s practical, reliable and valid method that promises to be of considerable value. It
can be used together with histopathology for postmortem detection of visually unapparent acute myocardial
infarcts.