Cardiac-specific troponin-I (cTnI) in a post-mortem setting

Abstract

Cardiac-specific troponin (cTn) is widely used in clinical medicine to support a diagnosis of acute myocardial infarction. Several studies have explored the value of cTn testing in deceased individuals. These studies suggest that -although there are important limitations associated with its use- post-mortem cTn can be useful in selected cases. A decision for post-mortem cTn testing should however be influenced by factors that have not been explored in much detail. This includes the success rate of post-mortem cTn testing, and whether cTn levels are stable after death.Therefore, this study addresses the post-mortem availability and stability of cardiac-specific Troponin I (cTnI). Post-mortem availability was determined by analysing the success rate in 250 high-sensitivity (hs-)cTnI tests on post-mortem blood samples, and its relationship with variables such as sample location, sample type, post-mortem interval, and decomposition. Post-mortem stability was explored by comparing post-mortem cTnI levels between two samples from the same individual, taken at different times.Post-mortem hs-cTnI tests were successful in 86.4% of cases (216/250), with little effect of sex, age, or cardiopulmonary resuscitation. Visible decomposition precluded a successful test. Other variables associated with decomposition (such as increased post-mortem interval) also affected test success negatively. Our results furthermore suggest that cTnI is very unstable post-mortem, with marked differences in hs-cTnI test results between samples from the same individual. The differences were large (on average 18734 ng/L) and not unidirectional. Instability appeared to increase with larger time intervals, but the results were overall erratic and difficult to interpret.We conclude that hs-cTnI testing results are generally available in a post-mortem setting, but that testing should be performed on the earliest available blood sample. Samples from decomposed individuals should not be tested. Furthermore, the severe instability of cTnI indicates that any post-mortem hs-cTnI result must be interpreted with caution.

Keywords: Autopsy; Biochemistry; Blood analysis; Decomposition; Forensic medicine; Pathology; Sudden cardiac death; Troponin; cTnI.

Fig. 1

Differences in cardiac troponin I (cTnI, in ng/L) concentration between blood samples collected at admission and autopsy. The cases are ordered on the X-axis based on time interval between admission and autopsy (see Table 1for time intervals). Only a minority of cases show a difference of 0. Differences appear to increase with increased time interval, particularly from case 21 onwards. However, large differences are already observed with shorter intervals whilst later cases returned differences of (close to) 0