The negative coroner's necropsy: a personal approach and consideration of difficulties

Challenges of genetics in the diagnosis of sudden cardiac death. Interest for forensic and legal medicine

Sudden cardiac death is the leading cause of death in developed countries and a small but significant number of cases cannot be explained after a thorough autopsy process. Cases of sudden cardiac death in people under 40years of age are mainly due to structural heart disease or cardiomyopathies and arrhythmogenic diseases or channelopathies. In these cases, the search for associated genetic factors through molecular autopsy may help to find the cause of unexplained sudden cardiac death, through genetic diagnosis of previously undiagnosed channelopathies or cardiomyopathies. The finding of genetic variants classified as pathogenic associated with cardiac pathology would conclude the autopsy result and provide the possibility of genetic screening in other family members.

Cohort-based nomogram for forensic prediction of SCD: a single-center pilot study

Forensic diagnosis of sudden cardiac death (SCD) is an extremely important part of routine forensic practice. The present study aimed to develop and validate nomograms for predicting the probability of SCD with special regards to ischemic heart disease-induced SCD (IHD-induced SCD) based on multiple autopsy variables. A total of 3322 cases, were enrolled and randomly assigned into a training cohort (n = 2325) and a validation cohort (n = 997), respectively. Prediction models of SCD and IHD-induced SCD were developed through multivariable logistic regression based on variables selected by LASSO regression or ridge regression, and prediction model with higher area under the curve (AUC) of the receiver operating characteristic (ROC) curve in the validation cohort was used to establish nomograms. For SCD prediction, discrimination of the nomogram was determined based on the ROC with AUC of 0.751 (95% CI, 0.726-0.775) and 0.735 (95% CI, 0.696-0.774) in the training cohort and validation cohort respectively. The AUC of IHD-induced SCD prediction nomogram in the training cohort and validation cohort were 0.742 (95% CI, 0.716-0.768) and 0.738 (95% CI, 0.698-0.777). To facilitate the use of nomograms in routine casework in forensic practice, web calculators ( https://forensic.shinyapps.io/Forensic_SCD/ , https://forensic.shinyapps.io/Forensic_IHDinducedSCD/ ) were constructed. In conclusion, the present study developed and validated simple and practical nomograms for predicting the probability of SCD and IHD-induced SCD based on multiple autopsy variables. The nomograms have certain efficiency for discrimination and calibration to provide a novel approach to diagnose cause of death, and may become a valuable tool in forensic practice.

Postmortem biochemical analysis of soluble ST2 in the pericardial fluid of patients with sudden cardiac death caused by ischemic heart disease: a pilot study

Soluble growth stimulation expressed gene 2 protein (sST2) is a myocardial protein induced by biomechanical stress. sST2 is widely present in the serum of patients with heart failure and is recommended as an important indicator to predict adverse outcomes in these patients. However, no postmortem biochemical analysis of sST2 in forensic practice has been reported. The present pilot study aimed to investigate the expression of sST2 in the pericardial fluid of patients with sudden cardiac death (SCD) caused by ischemic heart disease (IHD). In addition, to explore the relationship of sST2 with CK-MB, cTnT, and NT-proBNP, which have been proven to be auxiliary biomarkers for the diagnosis of SCD, we analyzed CK-MB, cTnT, NT-proBNP, and sST2 levels in twenty-one pericardial fluid samples from the Center of Forensic Investigation, China Medical University, with a Roche cobas e 411 electrochemiluminescence automatic immunoassay system and ST2/IL-33R Valukine™ enzyme-linked immunosorbent assay kit. The levels of sST2 in the pericardial fluid of patients with SCD caused by IHD were significantly increased (P < 0.01) and positively correlated with CK-MB and NT-proBNP (P < 0.0001). Receiver operating characteristic curve analysis indicated that the combined measurement of sST2 and NT-proBNP has a higher diagnostic value for SCD caused by IHD than the measurement of either indicator alone. This study preliminarily demonstrated that sST2 in the pericardial fluid was significantly increased in patients with SCD caused by IHD and might be used as a novel auxiliary biomarker for postmortem diagnosis of SCD in forensic practice.

The Role of miRNA Expression Profile in Sudden Cardiac Death Cases

Sudden cardiac death (SCD) is one of the leading causes of death in the world and for this reason it has attracted the attention of numerous researchers in the field of legal medicine. It is not easy to determine the cause in a SCD case and the available methods used for diagnosis cannot always give an exhaustive answer. In addition, the molecular analysis of genes does not lead to a clear conclusion, but it could be interesting to focus attention on the expression level of miRNAs, a class of non-coding RNA of about 22 nucleotides. The role of miRNAs is to regulate the gene expression through complementary binding to 3'-untraslated regions of miRNAs, leading to the inhibition of translation or to mRNA degradation. In recent years, several studies were performed with the aim of exploring the use of these molecules as biomarkers for SCD cases, and to also distinguish the causes that lead to cardiac death. In this review, we summarize experiments, evidence, and results of different studies on the implication of miRNAs in SCD cases. We discuss the different biological starting materials with their respective advantages and disadvantages, studying miRNA expression on tissue (fresh-frozen tissue and FFPE tissue), circulating cell-free miRNAs in blood of patients affected by cardiac disease at high risk of SCD, and exosomal miRNAs analyzed from serum of people who died from SCD.

Molecular autopsy: Twenty years of post-mortem diagnosis in sudden cardiac death

In the forensic medicine field, molecular autopsy is the post-mortem genetic analysis performed to attempt to unravel the cause of decease in cases remaining unexplained after a comprehensive forensic autopsy. This negative autopsy, classified as negative or non-conclusive, usually occurs in young population. In these cases, in which the cause of death is unascertained after a thorough autopsy, an underlying inherited arrhythmogenic syndrome is the main suspected cause of death. Next-generation sequencing allows a rapid and cost-effectives genetic analysis, identifying a rare variant classified as potentially pathogenic in up to 25% of sudden death cases in young population. The first symptom of an inherited arrhythmogenic disease may be a malignant arrhythmia, and even sudden death. Early identification of a pathogenic genetic alteration associated with an inherited arrhythmogenic syndrome may help to adopt preventive personalized measures to reduce risk of malignant arrhythmias and sudden death in the victim's relatives, at risk despite being asymptomatic. The current main challenge is a proper genetic interpretation of variants identified and useful clinical translation. The implications of this personalized translational medicine are multifaceted, requiring the dedication of a specialized team, including forensic scientists, pathologists, cardiologists, pediatric cardiologists, and geneticists.

Molecular autopsy in sudden cardiac death

A post-mortem genetic analysis in the process of investigating a sudden death episode is known as 'molecular autopsy'. It is usually performed in cases without a conclusive cause of death and after a comprehensive medico-legal autopsy. In these sudden unexplained death cases, an underlying inherited arrhythmogenic cardiac disease is the main suspected cause of death. The objective is to unravel a genetic diagnosis of the victim, but it also enables cascade genetic screening of the victim's relatives. Early identification of a deleterious genetic alteration associated with an inherited arrhythmogenic disease may help to adopt preventive personalized measures to reduce risk of malignant arrhythmias and sudden death. It is important to remark that the first symptom of an inherited arrhythmogenic cardiac disease may the malignant arrhythmia and even sudden death. Next-generation sequencing allows a rapid and cost-effectives genetic analysis. Close interaction between the forensic scientist, pathologist, cardiologist, pediatric cardiologist and geneticist has allowed a progressive increase of genetic yield in recent years, identifying the pathogenic genetic alteration. However, large numbers of rare genetic alterations remain classified as having an ambiguous role, impeding a proper genetic interpretation and useful translation into both forensic and cardiological arena.

Analyses of N-Terminal Pro-Brain Natriuretic Peptide, Cardiac Troponin T, and Creatine Kinase MB in Pericardial Fluid in Sudden Cardiac Death Caused by Ischemic Heart Disease

Background:

Biochemical analyses of N-terminal pro-brain natriuretic peptide (NT-proBNP), cardiac troponin T (cTnT), and creatine kinase MB (CK-MB) have been reported to be valuable for the auxiliary diagnosis of sudden cardiac death (SCD) in previous forensic studies.

Aims and Objectives:

The present study aimed to evaluate the diagnostic efficiency of combined analyses of NT-proBNP, cTnT and CK-MB in the pericardial fluid for forensic diagnosis of SCD caused by ischemic heart disease.

Materials and Methods:

Levels of NT-proBNP, cTnT, and CK-MB in the pericardial fluid of 132 medicolegal autopsy cases were obtained through electrochemiluminescence method.

Results:

NT-proBNP, cTnT, and CK-MB levels were significantly elevated in SCD cases (P < 0.05). Receiver-operating characteristics (ROC) analysis showed that NT-proBNP, cTnT, and CK-MB have diagnostic value for the diagnosis of SCD: NT-proBNP, cutoff value of 2236 pg/ml; cTnT, cutoff value of 199.51 ng/ml; CK-MB: cutoff value of 2742.5 ng/ml, and the combined analyses of these three biomarkers have better diagnostic efficiency than each single biomarker alone. Moreover, the causes of SCD were sub-divided into acute ischemic heart disease, acute myocardial infarction (AMI), and recurrent myocardial infarction subgroups for further analysis, which revealed that the ratio of cTnT/CK-MB could be used to distinguish AMI with the cutoff value of 0.1085 estimated by ROC analysis.

Conclusion:

These observations suggested that the postmortem biochemical analyses of NT-proBNP, cTnT, and CK-MB in the pericardial fluid may assist to diagnose SCD in forensic practice, and the combined analyses of multiple biomarkers have better diagnostic efficiency than each single biomarker alone. On the basis of the postmortem biochemical analyses of NT-proBNP, cTnT and CK-MB, combining the ratio of cTnT/CK-MB could be used to distinguish AMI.

Correctly Identifying Deaths Due to Drug Toxicity Without a Forensic Autopsy

In 2005, the National Association of Medical Examiners approved the Forensic Autopsy Performance Standards. Standard B3.7 indicates that a forensic pathologist shall perform a forensic autopsy when the death is by apparent intoxication by alcohol, drugs, or poison.The Jefferson County Coroner/Medical Examiner Office has observed an increase in our caseload by 10% per year since 2012. We designed a study to determine if a pathologist could correctly classify the cause of death (COD) and manner of death (MOD) of suspected drug-related deaths without information from the internal examination. The determination of the COD and MOD was then compared with the case file, which includes information from the internal examination and microscopy, to determine agreement between the case file and the reclassification. The percent correct for COD and MOD was calculated, and kappa values were calculated for MOD.The pathologists were able to correctly classify the COD in 73% of cases. For MOD, 2 pathologists achieved substantial agreement between the test cases and the actual case file. The third pathologist had moderate agreement. These findings indicate that a full postmortem examination is necessary to correctly classify the COD/MOD in cases of suspected drug toxicity.Our null hypothesis is that a full autopsy is not necessary to correctly classify the COD and MOD in cases of drug toxicity.

BNP and NT-proBNP as Diagnostic Biomarkers for Cardiac Dysfunction in Both Clinical and Forensic Medicine

Currently, brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are widely used as diagnostic biomarkers for heart failure (HF) and cardiac dysfunction in clinical medicine. They are also used as postmortem biomarkers reflecting cardiac function of the deceased before death in forensic medicine. Several previous studies have reviewed BNP and NT-proBNP in clinical medicine, however, few articles have reviewed their application in forensic medicine. The present article reviews the biological features, the research and application status, and the future research prospects of BNP and NT-proBNP in both clinical medicine and forensic medicine, thereby providing valuable assistance for clinicians and forensic pathologists.

[Molecular autopsy in sudden cardiac death]

Currently, there are a significant percentage of autopsies left without a conclusive diagnosis of death, especially when this lethal event occurs suddenly. Genetic analysis has been recently incorporated into the field of forensic medicine, especially in patients with sudden death and where no conclusive cause of death is identified after a complete medical-legal autopsy. Inherited arrhythmogenic diseases are the main cause of death in these cases. To date, more than 40 genes have been associated with arrhythmogenic disease, and causing sudden cardiac death has been described. The main arrhythmogenic diseases are Long QT Syndrome, Catecholaminergic Polymorphic Ventricular Tachycardia, Brugada Syndrome, and Short QT Syndrome. These post-mortem genetic studies, not only allow a diagnosis of the cause of death, but also allow a clinical translation in relatives, focusing on the early identification of individuals at risk of syncope, as well as adopting personalised therapeutic measures for the prevention of a lethal arrhythmic episode.

Differential expression of B-type natriuretic peptide between left and right ventricles, with particular regard to sudden cardiac death

The aim of the present study was to investigate the differential expression of B-type natriuretic peptide (BNP) between the left and right ventricle (RV) in sudden cardiac death (SCD). A total of 26 forensic autopsy cases of sudden death (survival time <30 min, postmortem interval <48 h or frozen within 6 h following death) in the present institute were examined. The cases consisted of acute ischemic heart disease (AIHD, n=15) with/without apparent myocardial necrosis as a sign of infarction (acute myocardial infarction, n=6; ischemic heart disease, IHD, n=9), and arrhythmogenic right ventricular cardiomyopathy (ARVC/D, n=5), in addition to traffic accidents and high falls without any pre existing heart disease as control (C, total n=6). BNP was investigated in all cases by the colloidal gold method, hematoxylin-eosin staining, immunohistochemistry (IHC) and the molecular pathological method. The IHC results demonstrated that a positive BNP immunostaining was detected in all groups; however, there was no difference between different causes of death. Pericardial N-terminal (NT)-proBNP concentration was significantly increased in deaths resulting from AIHD and ARVC/D compared with control group. The relative quantification of BNP mRNA demonstrated that relative expression levels of BNP mRNA were significantly increased in the left ventricle (LV) in the AIHD group, and in the RV of the ARVC/D group. The relative quantification difference and ratio of BNP mRNA between LV and RV demonstrated a significantly greater value in the AIHD group compared with control group. BNP mRNA in myocardium and NT-proBNP concentration in pericardial fluid were elevated in SCD patients, and left ventricular dysfunction predominated in AIHD patients, whereas right ventricular dysfunction predominated in ARVC/D patients. The results of the present study suggest the possible use of molecular pathology of BNP for the determination of terminal cardiac function in SCD and analysis of its fatal mechanism in forensic practice.

Natural and Undetermined Sudden Death: Value of Post-Mortem Genetic Investigation

BACKGROUND

Sudden unexplained death may be the first manifestation of an unknown inherited cardiac disease. Current genetic technologies may enable the unraveling of an etiology and the identification of relatives at risk. The aim of our study was to define the etiology of natural deaths, younger than 50 years of age, and to investigate whether genetic defects associated with cardiac diseases could provide a potential etiology for the unexplained cases.

METHODS AND FINDINGS

Our cohort included a total of 789 consecutive cases (77.19% males) <50 years old (average 38.6±12.2 years old) who died suddenly from non-violent causes. A comprehensive autopsy was performed according to current forensic guidelines. During autopsy a cause of death was identified in most cases (81.1%), mainly due to cardiac alterations (56.87%). In unexplained cases, genetic analysis of the main genes associated with sudden cardiac death was performed using Next Generation Sequencing technology. Genetic analysis was performed in suspected inherited diseases (cardiomyopathy) and in unexplained death, with identification of potentially pathogenic variants in nearly 50% and 40% of samples, respectively.

CONCLUSIONS

Cardiac disease is the most important cause of sudden death, especially after the age of 40. Close to 10% of cases may remain unexplained after a complete autopsy investigation. Molecular autopsy may provide an explanation for a significant part of these unexplained cases. Identification of genetic variations enables genetic counseling and undertaking of preventive measures in relatives at risk.

Negative autopsy and sudden cardiac death

Forensic medicine defines the unexplained sudden death as a death with a non-conclusive diagnosis after autopsy. Molecular diagnosis is being progressively incorporated in forensics, mainly due to improvement in genetics. New genetic technologies may help to identify the genetic cause of death, despite clinical interpretation of genetic data remains the current challenge. The identification of an inheritable defect responsible for arrhythmogenic syndromes could help to adopt preventive measures in family members, many of them asymptomatic but at risk of sudden death. This multidisciplinary translational research requires a specialized team.

How can we reduce the number of coroner autopsies? Lessons from Scotland and the Dundee initiative

Currently the medicolegal dissection rate for England and Wales is 22% (110,000 coronial autopsies for 500,000 deaths per annum), yet there is a general lack of evidence about the utility of and justification for such a high level of activity, which is between double and triple the rate in other jurisdictions. The government is currently consulting on how to reduce the numbers, and the Coroners and Justice Act 2009 is permissive of external examinations as an alternative to dissections. We describe the philosophy and practice of the Scottish system of postmortem external examinations, and the 20-year experience of a local initiative to maximize use of such external examinations. Currently our regional medicolegal dissection rate is 6%, which if applied to England and Wales would reduce the number of dissections from 110,000 to 30,000 per annum, with all of the social, resource and management implications. While the autopsy is an important tool in modern death investigation, an almost automatic recourse to it is inappropriate. In our view external examinations are not only cost-effective but also a necessary element in any death investigative system which wishes to strike an appropriate balance between intrusion by the state and the rights of the bereaved.

Sudden adult death

In the investigation of sudden death in adults, channelopathies, such as long QT syndrome, have risen to the fore in the minds of forensic pathologists in recent years. Examples of these disorders are touched upon in this review as an absence of abnormal findings at postmortem examination is characteristic and the importance of considering the diagnosis lies in the heritable nature of these conditions. Typically, a diagnosis of a possible channelopathy is evoked as an explanation for a 'negative autopsy' in a case of apparent sudden natural death. However, the one potential adverse effect of this approach is that subtle causes of sudden death may be overlooked. The intention of this article is to review and discuss potential causes of sudden adult death (mostly natural) that should be considered before resorting to a diagnosis of possible channelopathy. Nonetheless, it becomes apparent that many of the potential causes of sudden death can have a genetic basis. Thus, it becomes an important consideration that there may be a genetic basis to sudden death that extends beyond the negative autopsy.

The negative autopsy: sudden cardiac death or other?

One of the most frustrating challenges faced by the forensic pathologist is the inability to determine the cause of death in a young person previously thought healthy. The four steps in the investigation of a sudden death include obtaining the history and scene information, performing a gross and microscopic autopsy, performing appropriate laboratory tests, and making the diagnosis. When examining the heart grossly it is important to preserve the anatomic landmarks, section the coronary arteries closely, and recognize lethal abnormalities such as anomalous origin of the coronary arteries. Specimens useful for toxicologic analysis include whole blood, serum, vitreous humor, gastric contents, bile, urine a purple top tube of blood, and frozen myocardium and spleen. Lethal cardiac diseases with minimal or no anatomic findings include Brugada and Garg's syndromes, the long QT syndrome, and Wolff-Parkinson-White (WPW) syndrome. Consultation with other experts, including cardiac pathologists, cardiologists, electrophysiologists, and molecular biologists, may be helpful in determining a cause of death.

Unexplained and explained natural deaths among persons above 1 year of age in a series of medico-legal autopsies

The aim of this study was to describe unexplained and explained natural deaths among decreased above 1 year of age in a series of medico-legal autopsies collected over a 20-year period (1972-1992). Unexplained natural deaths can be defined as those deaths where no cause-of-death is revealed after post-mortem and without circumstances indicating violent death. The death was considered to be natural in 491 cases above 1 year of age among a total of 2004 medico-legal autopsies. In 428 of these cases an explanation as to the cause-of-death was reached. The three most frequently encountered causes-of-death were complications to coronary atherosclerosis (62.6%), diseases of the lung (12.4%) and diseases in the central nervous system (9.8%). Among 59 cases with unexplained natural death, 50 had various chronic diseases or fatty liver. In 43 of these cases the deceased had epilepsy or chronic alcoholism. In nine cases (1.8% of the natural deaths) no explanation to the cause-of-death could be given.

A review of the forensic investigation of scuba diving deaths

With more people engaging in recreational scuba diving, fatalities from this sport are encountered by forensic investigators. There is a plethora of factors contributing to death and the investigator must be acquainted with how to elucidate them. The emphasis is on a multi-disciplinary approach that involves co-divers and instructors, the rescue team, the police, forensic scientists, diving equipment suppliers, underwater physiologists and physicians, decompression chamber personnel, general practitioners, relatives and the forensic pathologist. This report presents the various factors contributing to scuba diving deaths and suggests how to conduct such investigations.