Necropsy study of association between sudden death and cardiac enzymes

Diagnostic role of postmortem CK-MB in cardiac death: a systematic review and meta-analysis

Biochemical analysis of creatine kinase MB (CK-MB), which is a biomarker of myocardial damage, is used as a potential adjunct test in clinical and forensic medicine. However, there is no previous meta-analysis that summarizes the diagnostic value of postmortem biochemical analysis of CK-MB in cardiac death. The purpose of this study was to perform a systematic literature review and meta-analysis of postmortem CK-MB in cardiac death for forensic work. Six online databases, including PubMed, Embase, Cochrane Library, the China National Knowledge Infrastructure (CNKI), the China Biomedical Literature Database (CBM), and Wanfang Data, were used to search for related studies. The quality of the included literature was assessed according to the Newcastle-Ottawa Quality Assessment Scale (NOS). The meta-analysis was performed by Review Manager version 5.3 software to investigate the diagnostic role of postmortem CK-MB in cardiac death, especially in myocardial infarction. Sixteen pieces of related literature were identified, all of which were considered high quality. The results of the meta-analysis revealed that the postmortem CK-MB level in the pericardial fluid was significantly higher in the cardiac death group with a standard mean difference (SMD) = 0.63, 95% confidence interval (CI) = 0.09~1.17, p = 0.02. This was also the result in the myocardial infarction group (SMD = 0.83, 95% CI = 0.10~1.56, p = 0.03). No significant difference in CK-MB was found in serum for cardiac death (SMD = -0.31, 95% CI = -0.85~0.24, p = 0.27) or myocardial infarction (SMD = -0.10, 95% CI = -0.69~0.49, p = 0.74). The postmortem biochemical analysis of CK-MB in the pericardial fluid can be used as an auxiliary method in the postmortem diagnosis of cardiac death, along with autopsy and histological investigation.

Cardiac troponins and NT-proBNP in the forensic setting: Overview of sampling site, postmortem interval, cardiopulmonary resuscitation, and review of the literature

The possible use of biochemical markers in the postmortem diagnosis of myocardial ischemia is well known in the forensic setting, though several issues have limited its widespread adoption. The study presented herein focuses of N-terminal pro-B-type natriuretic peptide, troponin T, and troponin I, and the possible influence due to sampling site chosen, postmortem interval elapsed, and cardiopulmonary resuscitation attempts. Comparisons were performed between antemortem serum levels of these markers and postmortem levels measured in pericardial fluid and postmortem serum samples obtained from different sampling sites (n=16). Levels of these markers were also compared in cases characterized by various postmortem intervals (n=48, consisting of 24 ischemic heart disease cases and 24 controls) as well as in cases with and without cardiopulmonary resuscitation (n=22, consisting of 14 cases of hanging and 8 cases of drug intoxication). Our results indicate that N-terminal pro-B-type natriuretic peptide, troponin T, and troponin I values determined in postmortem serum from femoral blood (collected up to 24h after death) do not differ significantly from those measured in venous blood antemortem serum samples (collected at the upper limbs). In addition, our results reveal that the time elapsed after death should always be taken into consideration when cardiac troponins are measured in postmortem samples. Lastly, our findings reveal the absence of statistically significant differences between levels of the tested biomarkers (in postmortem serum from femoral blood) in cases without cardiopulmonary resuscitation compared to cases with cardiopulmonary resuscitation (at least for postmortem intervals up to 24h).

Postmortem cardiac troponin-I levels predict intramyocardial damage at autopsy

Serum cardiac troponin levels are now widely used in the diagnosis of myocardial infarct (MI) and injury in living patients, but their utility in postmortem diagnosis has not been established. We evaluated postmortem cardiac troponin-I (cTnI) levels in serum from 53 hospital patients undergoing autopsy and correlated the levels with anatomic findings at postmortem examination. Among patients with nonischemic cardiac disease, those with intramyocardial disease (e.g., cardiac transplant rejection, intramyocardial tumor) had significantly higher cTnI levels than those with disease confined to the pericardium (e.g., epicardial tumor implants, pericarditis) (p = 0.004). No correlation was found between recent MI and cTnI level. There was also no correlation between cTnI level and the presence of chronic ischemic features, a history of cardiopulmonary resuscitation, or postmortem interval. We conclude that cTnI is detectable in postmortem serum samples and, although its levels did not correlate specifically with ischemia or infarction in our series, its levels appear to correlate significantly with intramyocardial injury. Use of cardiac troponin in the postmortem diagnosis of cardiac disease may be warranted.

Sudden death: correlation histopathological and biochemical

The causes of sudden cardiac death are diverse and are function of age. In young people, coronary anomalies, hypertrophic cardiomyopathy are the most common findings at autopsies; in adults, coronary atherosclerosis and acquired forms of cardiomyopathy are frequent findings. In many of non-ischemia related cases autopsies are unrevealing. One of the most frustrating challenges is the inability to determine the cause of death in a person previously healthy. The majority of such sudden deaths are caused by acute ventricular tachyarrhythmias, but unfortunately unassociated with structural injury to the heart. The present work evaluates incidence, clinical data, and laboratory tests. Biochemical studies on serum, pericardial fluid, vitreous humour and pathological characteristics of 38 cases of sudden cardiac death from 2003 were investigated by us. Also, non-cardiac natural causes of death must be excluded.

A study of various morphologic variables and troponin I in pericardial fluid as possible discriminators of sudden cardiac death

Pathologists frequently examine victims of sudden cardiac death. In some cases, a firm diagnosis of cardiac-related death can be made based on conclusive gross and histologic findings. In many other cases, we find evidence supportive of, but not diagnostic of, cardiac death (e.g., atherosclerotic coronary artery disease, cardiomegaly, myocardial scarring). A final cohort consists of cases of sudden death with minimal to mild cardiac disease, no other significant pathology, and negative toxicologic studies. This prospective study compared 38 cardiac-related deaths with 52 control cases with respect to concentrations of pericardial cardiac troponin I (cTnI), heart weight, evidence of old and/or recent myocardial injury, and presence of significant coronary artery disease. The influence of documented chest trauma and/or perimortem cardiopulmonary resuscitation (CPR) on levels of cTnI was also analyzed. Even though median cTnI levels were significantly higher in cardiac deaths than in controls (p = .003), cTnI was not found to be a significant predictor of cardiac deaths, as determined by discriminant analysis (p = .52). Heart weight >500 g, evidence of old and recent myocardial injury, and significant coronary artery disease were seen statistically more often in cardiac deaths than in controls (p < or = .005 in each case), and median age was significantly higher in cardiac deaths than in controls (p = .001). Based on a stepwise logistic regression model, significant coronary artery disease, old and recent myocardial injury, and heart weight >500 g were found to contribute significantly to the prediction of cardiac death. Finally, neither chest injury nor CPR significantly affected concentrations of cTnI in pericardial fluid. These data confirm that the presence of acute and remote myocardial injury, significant coronary artery disease, and cardiomegaly (heart weight >500 g) strongly supports the diagnosis of a cardiac-related death. In contrast to a recently published report, we do not find that elevated concentrations of cTnI in pericardial fluid are strong indicators of cardiac-related deaths using our methodology.

Serum concentrations of cardiac troponin I in sudden death: a pilot study

Sudden cardiac death due to lethal arrhythmia may be the initial presenting symptom of ischemic heart disease. In many cases, in the absence of trauma, a majority of these deaths will be visually inspected by a medical examiner and released with death being ascribed to atherosclerotic cardiovascular disease, coronary artery disease, arrhythmia, myocardial infarction, or a similar diagnosis. When an autopsy is performed, there may be significant cardiovascular disease but no gross or histologic evidence of an acute myocardial infarct unless the patient survived for several hours following the event. Biochemical assays of creatine kinase MB fraction (CKMB) performed on serum have been used to document myocardial injury in the absence of morphologic changes. Newly developed assays for cardiac troponin I (cTnI) may detect myocardial injury with a greater sensitivity than CKMB. A prospective study was performed on 28 autopsied patients at the Office of the Chief Medical Examiner of the state of Maryland. Subclavian blood was sampled for subsequent analysis of serum CKMB and cTnI. In 3 cases of cardiac-related death, there was insufficient plasma for analysis of both CKMB and cTnI, and only CKMB was quantitated. In 12 cases, hemolysis rendered interpretation questionable. Of the remaining 16 cases, the mean serum CKMB level was 857.9 ng/ml (n = 7) and the cTnI level was 93.4 ng/ml (n = 4) for cardiac-related deaths, compared with mean CKMB levels of 116.4 ng/ml (n = 9) and mean cTnI levels of 16.6 ng/ml (n = 9) for non-cardiac-related deaths. The differences in serum elevation of both CKMB and cTnI noted between the cardiac- and non-cardiac-related deaths were statistically significant. Serum cTnI concentrations >40 ng/ml were only noted in cardiac-related deaths. These data suggest that an elevated postmortem serum concentration of cTnI reflects ischemic heart disease and supports its use in determining cause of death. Quantitation of this analyte may prove useful when death may be due to an arrhythmia following a morphologically undetectable microinfarct.

Nuclear morphometry of the myocardial cells as a diagnostic tool in cases of sudden death due to coronary thrombosis

Sudden cardiac death due to underlying coronary artery thrombosis is one of the leading causes of death. However, in a significant percentage of individuals who died suddenly, no indication of myocardial infarction is found during post-mortem examination, especially when the time interval between appearance of symptoms and death is short. In the present study, we have evaluated certain nuclear morphometric parameters, such as, minimum, maximum, mean and standard deviation of perimeter and area in 20 individuals who died of coronary artery thrombosis, within 1 h from symptoms onset. Furthermore, the above parameters were compared with those of a control population of 20 individuals whose sudden death was caused by traffic accidents. Statistical elaboration of the results by means of t-test, Mann-Whitney (U-test) and analysis of covariance (adjusting for age), showed a statistically significant difference for all variables except for the minimum area. With stepwise discriminant analysis method, the mean perimeter was selected as the best predictor of cardiac death. Mean perimeter achieved a correct reclassification percentage (based on Fisher's linear discriminant function) of 92.5% (85% and 100% for cases and controls, respectively). Moreover, by applying the cut-off of 172 microns, we could identify the individuals who died suddenly because of coronary artery thrombosis with a specificity of 100% (sensitivity 85%, P < 0.001). Our results show that nuclear morphometry of the myocardial cells is a reliable diagnostic tool for the diagnosis of coronary thrombosis based lesion in cases of sudden death, even when methods trying to verify the presence of infarction fail to do so.

Pericardial fluid postmortem: Comparative study of natural and violent deaths

Thanatochemistry is an increasingly important ancillary procedure in forensic practice. Alterations are known to take place in biochemical components during the postmortem period, particularly in the blood, and both research results and their interpretation have been the object of some controversy. For that reason, emphasis has been placed on the examination of fluids that are neither altered nor contaminated as rapidly as blood after death. This study tested the hypothesis that pericardial fluid (PF) may be a suitable medium for biochemical analysis in corpses. The study sought to determine concentrations of urea, creatinine, glucose, creatinine kinase 2, proteins, calcium, sodium, and potassium, in the pericardial fluid of corpses. The study sample was divided into two groups, natural deaths and violent deaths. Intergroup results were compared, using Mann-Whitney's U test for paired data. No significant differences were obtained between the natural death and violent death groups for the parameters studied, with the exception of urea (p < .05). Further studies are required to compare these results and create the possibility for new conclusions.

Antioxidant-related enzymes in myocardial zones and human pericardial fluid in relation to the cause of death

The aim of this work was to shed light on hypoxic and ischemic processes in the heart that may lead to irreversible or lethal myocardial injury. We determined malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities in human cardiac tissues from 45 medico-legal autopsies of persons who died from different causes. Samples were taken from three different areas of myocardium: the anterior and posterior walls of the left ventricle, and the interventricular septum. We used light microscopy to examine the heart sections (hematoxylin-eosin and Masson's trichromic stains), and studied the K+(Na+ ratio and pericardial fluid. A decrease in GSH-Px activity was found in cases with severe atherosclerosis of the coronary artery in comparison with the group with slight or moderate atherosclerosis. Postmortem activities of GSH-Px and SOD were significantly different in the three myocardial zones studied. An increase in GSH-Px activity in the interventricular septum was noted in cases of cardiac deaths. Antioxidant-related enzymes such as GSH-Px and SOD can therefore be regarded as new biochemical markers indicative of myocardial hypoxia. The possible applications to the postmortem diagnosis of the cause of death are discussed.

Necropsy study of the association between sudden cardiac death, cardiac isoenzymes and contraction band necrosis

AIMS

To assess whether a quantitative analysis of myocardial contraction bands could aid the postmortem identification of early myocardial infarction, especially if used in conjunction with cardiac isoenzyme activities.

METHODS

Sixty four coroner's necropsies were grouped by gross and histological findings into 26 cases of definite non-cardiac death, 12 cases of definite myocardial infarction and 26 cases in which there was occlusive coronary artery atheroma, but no demonstrable evidence of infarction. Using multiple sections of left ventricular myocardium stained with Heidenhain's iron haematoxylin, the number of myocardial cells containing contraction bands per unit area was quantified. The results were analysed statistically using logistic regression, and were then compared and combined with results from the statistical analysis of postmortem cardiac isoenzymes that had recently been undertaken on the same cases.

RESULTS

The number of cells containing contraction bands per unit area was higher in cases of definite myocardial infarction compared with those of non-cardiac deaths. In addition, cases of occlusive coronary artery atheroma only could be identified, indicating the presence of early myocardial infarction. The accuracy of this identification could be improved by combining these results with the results from the statistical analysis of postmortem cardiac isoenzymes.

CONCLUSION

The quantitative assessment of myocardial contraction band necrosis can provide useful additional information in cases of sudden death, where myocardial infarction is suspected but not identified on routine histological staining. The value of the information obtained is increased when used in conjunction with the postmortem measurement of cardiac isoenzyme activities.

Biochemical assessment of acute myocardial ischaemia

AIMS

To evaluate the efficacy of biochemical parameters in different fluids in the diagnosis of myocardial infarction of different causes, analysed after death.

METHODS

The myoglobin concentration and total creatine kinase (CK) and creatine kinase MB isoenzyme (CK-MB) activities were measured in serum, pericardial fluid, and vitreous humour from seven diagnostic groups of cadavers classified according to the severity of myocardial ischaemia and cause of death. Lactate dehydrogenase (LDH) and myosin were measured only in serum and pericardial fluid, and cathepsin D only in pericardial fluid. Routine haematoxylin and eosin and acridine orange staining were used for microscopy studies of heart tissue.

RESULTS

In pericardial fluid there were substantial differences between the different groups with respect to CK, CK-MB, and LDH activities and myosin concentrations. The highest values were found in cases with morphological evidence of myocardial ischaemia.

CONCLUSIONS

Biochemical parameters, which reach the pericardial fluid via passive diffusion and ultrafiltration due to a pressure gradient, were thus detectable in this fluid earlier than in serum in cases with myocardial ischaemia. These biochemical parameters may be of use for ruling out myocardial ischaemia in those controversial cases in which reliable morphological findings are lacking.