A rapid postmortem cardiac troponin T assay: laboratory evidence of sudden cardiac death

Postmortem examination may be useful in establishing the cause of sudden unexpected death. In many instances, however, limitations of staffing, budget, and time may force the pathologist to triage cases to external examination rather than autopsy. A rapid assay for cardiac troponin T (cTnT) to document suspected cardiac-related deaths may optimize the use of the time and resources of the autopsy pathologist. Peripheral blood was sampled percutaneously before each of 40 autopsies and placed in the well of the Cardiac T Rapid Assay unit in accordance with the included instructions, and the results were read after 15 minutes. The assay result, decedent age, postmortem interval, and evidence of cardiopulmonary resuscitation were tabulated and subsequently correlated with the cause of death. On final sign-out of each of the autopsies, the cause of death was determined to be cardiac-related (n = 20) versus the cause in non-cardiac control subjects (n = 20). This determination was made while the investigators were blinded to the cTnT assay result. Of the 20 cardiac deaths, 17 (85%) showed positive results for cTnT compared with 6 (30%) false-positive results among the 20 control cases; this result was statistically significant according to the chi-square test. In the over-50 age group, the sensitivity of this assay in detecting cardiac-related death was 91%, with a specificity of 86%. Perimortem cardiopulmonary resuscitation did not appear to result in false-positive results. In the appropriate setting, this rapid assay for cTnT can provide valuable data supportive of a cardiac-related death. This inexpensive test may best be used in triaging sudden deaths in persons over 50 to external examination versus complete autopsy.     

Investigation of cardiac troponins in postmortem subjects: comparing antemortem and postmortem levels

The limitations of autopsy in the diagnosis of death due to ischemic heart disease are well known. In the living, a simple reliable biochemical assay for cardiac troponins is used in the diagnosis of acute myocardial ischemia. Several studies have investigated the use of biochemical assays for cardiac troponins in postmortem subjects as a means to distinguish between a cardiac and anoncardiac cause of death. All of these studies, however, rely upon assigning subjects to "cardiac" or "noncardiac" death on the basis of a postmortem examination. As postmortem examination does not always accurately distinguish between these two groups, this approach is intrinsically flawed.Our study compares antemortem and postmortem cardiac troponin levels in five subjects. The antemortem samples were retrieved from the hospital biochemistry laboratory after each subject's death. The postmortem samples for each subject were taken from different sites and at different times during the early postmortem period.Erratic results bearing little or no relation to the antemortem cardiac troponin level were obtained for all subjects. Four of the five subjects had raised antemortem troponin levels, although only one had a cardiac cause of death.From this, we conclude that postmortem blood is not a suitable substrate for standard biochemical assays of cardiac troponins, which are designed for use on serum taken from living patients. In addition, the results of our study support the view that elevated cardiac troponins are a marker of serious morbidity and are not specific for cardiac injury as the primary cause of morbidity or mortality.     

Cardiac troponin T (cTn T) and the postmortem diagnosis of sudden death

PURPOSE: To evaluate the effectiveness of the increase of postmortem cardiac troponin T (cTn T) in acute disease-related deaths. METHODS: Peripheral venous blood was sampled from 39 autopsies performed. Thirty nonhemolyzed specimens were considered in the final analysis (n = 30).Only the calculation of the cTn T was performed using the Roche Diagnostics Elecsys 2010 Immunoassay System. The high limit and the cutoff are 25 ng/mL.Deaths were divided into 2 groups, according to sudden cardiac deaths (group 1, n = 15) and non-cardiac-related deaths without resuscitation (group 2, n = 15). RESULTS: All the cases with visual myocardial infarction had elevated concentrations of cTn T. The difference of the postmortem cTn T concentrations between resuscitated and nonresuscitated is nonsignificant.In the non-cardiac-related deaths, the elevated concentrations of cTn T were only noted in all cases of electrocution. CONCLUSION: In clinical practice, several biochemical markers are used for the diagnosis of myocardial infarction. Because of its extreme specificity for myocardial damage, cTn T and cardiac troponin I (cTn I) are frequently used. The results of these assays could then be used to facilitate selection for cases that may be released following histologic examinations.     

Intrapulmonary aquaporin-5 expression as a possible biomarker for discriminating smothering and choking from sudden cardiac death: a pilot study

The diagnosis of mechanical asphyxia as a cause of death, especially smothering and choking lacking evident injury, is one of the most difficult tasks in forensic pathology. The present study investigated the intrapulmonary expressions of aquaporins (AQPs; AQP-1 and AQP-5), as markers of water homeostasis, in forensic autopsy cases (total n=64, within 48 h postmortem) of mechanical asphyxiation due to neck compression (strangulation, n=24), including manual/ligature strangulation (n=12) and atypical hanging (n=12), smothering (n=7) and choking (n=8), compared with sudden cardiac death (n=14) and acute brain injury (n=11). Quantification of mRNA using a Taqman real-time PCR assay system demonstrated suppressed expression of AQP-5, but not AQP-1, in smothering and choking, compared with that in strangulation as well as sudden cardiac death and acute brain injury death. Immunostaining of AQP-5 was weakly detected in a linear pattern in the type I alveolar epithelial cells in smothering and choking cases, while cardiac and brain injury death showed marked positivity, and most strangulation cases had AQP-5-positive granular aggregates and fragments in intra-alveolar spaces. These observations indicate a partial difference in pulmonary molecular pathology among these causes of death, suggesting a procedure for possible discrimination of smothering and choking from sudden cardiac death.     

Evaluation of postmortem serum calcium and magnesium levels in relation to the causes of death in forensic autopsy

There appears to be very poor investigation of postmortem serum calcium (Ca) and magnesium (Mg) for diagnostic evidence to determine the cause of death. The aim of the present study was a comprehensive analysis of the serum levels in relation to the causes of death in routine casework. Autopsy cases (total, n=360; 5-48 h postmortem), including blunt injury (n=76), sharp injury (n=29), asphyxiation (n=42), drownings (n=28: freshwater, n=11; saltwater, n=17), fire fatalities (n=79), methamphetamine (MA) poisoning (n=8), delayed death from traumas (n=37), and acute myocardial infarction/ischemia (AMI, n=61), were examined. In total cases, there was no significant postmortem time-dependent rise in serum Ca and Mg. Both Ca and Mg levels in the heart and peripheral blood were significantly higher in saltwater drowning compared with those of the other groups. In addition, a significant elevation in the Ca level was observed in freshwater drowning and fire fatalities, and in the Mg level in fatal MA intoxication and asphyxiation. Topographic analyses suggested a rise in serum Ca and Mg due to aspirated saltwater in drowning, that in serum Ca in freshwater drowning and fire fatalities of peripheral skeletal muscle origin and that in serum Mg in MA fatality and asphyxiation of myocardial and/or peripheral origin. These markers may be useful especially for diagnosis and differentiation of salt- and freshwater drownings and may be also helpful to determine the causes of death involving skeletal muscle damage, including burns and MA intoxication.     

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.     

The relevance of the detection of troponins to the forensic diagnosis of cardiac contusion

The forensic diagnosis of cardiac contusion has hitherto been based mainly on anamnesis, concomitant thoracic injuries and the detection of macroscopic changes to the heart. Parallel histological and serological investigations of the heart-specific troponins have been conducted with varying results. This paper aims to show whether heart-specific troponins are suitable as a means of securing the diagnosis in proven cases of cardiac contusion and of determining which of the three heart-specific troponins cTnT, cTnI and cTnC are most significant in serology and histology for postmortem diagnosis. In the study, 25 cases of known cardiac contusion and 11 controls without vital myocardial trauma taken from autopsy material were prospectively investigated. Investigation of the venous serum revealed significant differences in the concentrations of the case and control groups for troponin T (mean value 5.5056 versus 0.4982; p=0.014), for troponin C (mean value 263.9280 versus 68.5640; p=0.001) and for troponin I (mean value 1404.0560 versus 36.1650; p=0.003). In histology there are also significantly different depletions between the groups investigated (cTnT: p=0.002; cTnC: p=0.003; cTnI: p<0.001) taking into account the autolysis time.     

Sudden cardiac death and myocardial ischemia indicators: a comparative study of four immunohistochemical markers

The postmortem diagnosis of acute myocardial infarction represents a current challenge for forensic pathologists, particularly when death occurs within minutes to a few hours after the ischemic insult. Among the adult population the single most important cause of sudden cardiac death (SCD) is the well-known atherosclerotic coronary artery disease, commonly asymptomatic or unrecognized. The recognition of early myocardial damage using routine hematoxylin and eosin (H&E) staining is possible only if death has occurred at least 6 hours after the onset of the ischemic injury. The usefulness of immunohistochemical markers to the diagnosis of early myocardial damage has been recently suggested because most of them can be visible even serologically as early as few minutes after the beginning of the symptoms. To evaluate the usefulness of plasma and cellular antigens, their distribution patterns have been studied among a group of 18 SCD cases in which a myocardial ischemia was strongly suspected. For the present study, 4 markers have been selected on the basis of their different diagnostic potential as follows: among the plasma markers the C5b-9 and fibronectin, among the cellular markers the myoglobin and cardiac troponin. The results show that only the study of multiple markers such as those selected can provide enough evidence of myocardial ischemia and/or necrosis, supporting the final diagnosis of SCD. No single immunohistochemical staining is ideal for diagnosing early myocardial ischemia but a set of markers can improve the ability of forensic pathologists to detect ischemic areas when no macroscopic or microscopic evidence of necrosis is available. However, the interpretation of data obtained in each individual cannot be isolated from the overall assessment of the factors (cardiopulmonary resuscitation and/or agonal artifacts) that can affect the expression of each marker.     

Postmortem serum catecholamine levels in relation to the cause of death

Catecholamines are major humoral factors and neurotransmitters that contribute to various stress responses. However, they have been considered unstable due to agony, terminal medical care and postmortem interference. The present study was a comprehensive investigation of postmortem serum levels of adrenaline (Adr), noradrenaline (Nad) and dopamine (DA) with regard to the cause of death in serial medicolegal autopsy cases (n=542) including fatalities from various traumas and diseases. There was a slight tendency toward postmortem increases of Nad and DA in cardiac blood as well as Adr and Nad in peripheral blood, a slight age-dependent decrease in Adr and DA in right heart blood, and a marked increase in serum DA due to administration during critical medical care. When these factors were taken into consideration, significantly higher cardiac blood levels were observed for Adr and Nad in injury and asphyxiation cases and for Adr in fatal methamphetamine (MA) abuse and other poisoning cases, whereas those levels were lower in fatal hypothermia. Drowning, fire fatality, acute cardiac death and cerebrovascular disease showed intermediate Adr and Nad levels. The DA level was elevated in cases of injury, hyperthermia, MA fatality and other poisoning. Topographical analyses suggested that the major sources of increased serum catecholamines in cases of injury was abdominal viscera including adrenal glands, and that in cases of asphyxiation, drowning, fire fatality, hyperthermia, MA fatality, other poisoning, acute cardiac death and cerebrovascular disease was the extremities in addition to abdominal viscera. However, there was in part a large case-to-case difference in each marker related to individual causes of death. These findings differed markedly from clinical observations and suggest that the postmortem serum catecholamine levels may reflect the magnitude of physical stress responses during the process of death in individual cases.     

缺血修饰白蛋白在急性缺血性心脏病中的法医学应用

目的探讨心包液中缺血修饰白蛋白(ischemia modified albumin,IMA)水平在心脏性猝死诊断中的应用价值及法医学意义。方法应用白蛋白-钴离子结合法检测急性缺血性心脏病组(36例)、急性心肌梗死组(6例)、心肌病组(4例)、对照组(15例)死者的心包液中IMA水平,比较各组之间IMA水平的差异。通过ROC曲线获得最佳IMA水平的截断值以及区分急性缺血性心脏病和对照组的敏感度和特异度。结果急性缺血性心脏病组心包液中IMA水平高于对照组(P0.05);而与急性心肌梗死组、心肌病组心包液中IMA水平比较,差异均无统计学意义(P0.05)。应用ROC曲线分析得出识别急性心肌缺血的IMA的截断值为40.65 U/m L,其诊断急性心肌缺血的敏感度为60.0%,特异度为80.5%。结论心包液中IMA有望作为诊断急性心肌缺血的参考指标,为心脏性猝死的法医学诊断提供客观依据。     

6例甲状腺功能亢进性心脏病猝死法医学分析

目的分析甲状腺功能亢进性心脏病(以下简称甲亢性心脏病)猝死案例,探讨其死亡的一般情况及法医病理学特点,为此类案件的法医病理学鉴定提供参考。方法收集中国医科大学法医学院2001—2016年6例甲亢性心脏病猝死案例,回顾性分析基本信息(性别与年龄)、临床表现、病史、解剖所见和组织病理学所见、生物化学检测指标、死亡原因。结果 6例案例多具有明确的甲状腺功能亢进病史,并表现出不同程度的心血管病症状;均具有明显的死亡诱因;甲状腺病理学检验符合弥漫性毒性甲状腺肿的表现;心脏质量均增加,心腔扩张,心肌肥大,灶状坏死;死后心包液的生物化学检测可作为甲亢性心脏病猝死的辅助手段。结论对甲亢性心脏病猝死案例进行诊断时应参考临床病史、尸体检验、组织病理学检验、死后毒(药)物检验等结果综合判定,必要时进行死后甲状腺和心功能的生物化学检测。     

Single-stranded DNA as an immunohistochemical marker of neuronal damage in human brain: an analysis of autopsy material with regard to the cause of death

Single-stranded DNA (ssDNA) is a marker of apoptosis and programmed cell death, which appears prior to DNA fragmentation during delayed neuronal death. The present study investigated the immunohistochemical distribution of ssDNA in the brain to investigate apoptotic neuronal damage with regard to the cause of death in medicolegal autopsy cases (n=305). Neuronal immunopositivity for ssDNA was globally detected in the brain, independent of the age, gender of subjects and postmortem interval, and depended on the cause of death. Higher positivity was typically found in the pallidum for delayed brain injury death and fatal carbon monoxide intoxication, and in the cerebral cortex, pallidum and substantia nigra for drug intoxication. For mechanical asphyxiation, a high positivity was detected in the cerebral cortex and pallidum, while the positivity was low in the substantia nigra. The neuronal ssDNA increased during the survival period within about 24h at each site, depending on the type of brain injury, and in the substantia nigra for other blunt injuries. The neuronal positivity was usually lower for drowning and acute ischemic disease. Topographical analysis of ssDNA-positive neurons may contribute to investigating the cause of brain damage and survival period after a fatal insult.     

Coronary thrombus and peracute myocardial infarction visualized by unenhanced postmortem MRI prior to autopsy

Sudden cardiac deaths are common within the community. They also constitute a substantial part of daily pathologic and forensic case work. However, macroscopic myocardial findings indicating acute ischemia are often absent. Then, diagnosis is based on coronary status in combination with indirect signs of acute cardiac failure. We present a case of sudden cardiac death where diagnosis was based on cardiac postmortem magnetic resonance imaging (pmMRI) findings already prior to autopsy: the heart's anterior basal ventricular septum showed hypointensities in T2-weighted images that raised suspicion of peracute ischemia. The lumen of the left anterior descending artery (LAD) exhibited a lack of otherwise discernible postmortem sedimentation of cellular blood components. Instead of a sharp border between serum and erythrocytes a homogeneous signal was seen within the narrowed lumen of the beginning LAD over a length of 1cm. Based on this, a thrombotic occlusion was assumed. Subsequent autopsy confirmed peracute septal myocardial ischemia secondary to a thrombotic occlusion of the LAD as concluded from the pmMRI.     

The relevance of the detection of troponins to the forensic diagnosis of cardiac contusion

The forensic diagnosis of cardiac contusion has hitherto been based mainly on anamnesis, concomitant thoracic injuries and the detection of macroscopic changes to the heart. Parallel histological and serological investigations of the heart-specific troponins have been conducted with varying results. This paper aims to show whether heart-specific troponins are suitable as a means of securing the diagnosis in proven cases of cardiac contusion and of determining which of the three heart-specific troponins cTnT, cTnI and cTnC are most significant in serology and histology for postmortem diagnosis.In the study, 25 cases of known cardiac contusion and 11 controls without vital myocardial trauma taken from autopsy material were prospectively investigated. Investigation of the venous serum revealed significant differences in the concentrations of the case and control groups for troponin T (mean value 5.5056 versus 0.4982; p = 0.014), for troponin C (mean value 263.9280 versus 68.5640; p = 0.001) and for troponin I (mean value 1404.0560 versus 36.1650; p = 0.003). In histology there are also significantly different depletions between the groups investigated (cTnT: p = 0.002; cTnC: p = 0.003; cTnI: p < 0.001) taking into account the autolysis time.     

心肌缺血再灌流损伤HSP70 mRNA原位杂交研究

目的观察家兔早期缺血再灌流损伤心肌组织热休克蛋白70 mRNA的表达变化,为心性猝死的法医病理学诊断寻找新的方法.方法建立家兔心肌缺血再灌流损伤模型,通过原位杂交技术观察研究.结果心肌缺血15min再灌流30min后,缺血区HSP70 mRNA阳性反应增强,阳性颗粒均匀散布于心肌全层,随着缺血时间的延长,阳性反应细胞数目逐渐增多,染色加深.结论HSP70 mRNA原位杂交检测可望为早期心肌缺血再灌流损伤的死后诊断提供新方法.     

心肌早期缺血再灌流损伤HSP70表达研究

目的　探讨早期缺血再灌流损伤心肌组织热休克蛋白 70 (HSP70 )的变化 ,为心源性猝死的法医病理学鉴定寻找新的依据。　方法　建立家兔早期心肌缺血再灌流动物模型 ,用免疫组化SABC法观察HSP70的表达。　结果　心肌缺血 15min再灌流 30min后 ,再灌流区心内膜下可见HSP70阳性表达 ;缺血30min再灌流 30min后 ,HSP70阳性反应细胞数目较多 ,散布于心肌全层 ;缺血 6 0min再灌流 30min后 ,再灌流区阳性表达明显减少 ,而其边缘见阳性表达略有增强。各实验组正常区和对照组心肌组织均未见阳性反应。　结论　心肌组织HSP70的阳性表达是一项显示心肌早期缺血再灌流损伤的灵敏指标 ,HSP70的免疫组化检测对缺血再灌流损伤所致心源性猝死的死后诊断具有一定的应用价值。     

心肌肌钙蛋白T在家兔缺血心肌中的表达及其死后稳定性

目的 探寻心肌肌钙蛋白T（cTnT）在家免缺血心肌中的表达规律及其死后稳定性．并对其在法医学实践中诊断早期心肌缺血的应用价值进行评价。方法用冠状动脉结扎法建立家兔急性心肌缺血模型．应用免疫组织化学法、图像分析和统计学处理系统,检测死后cTnT表达情况,并对实验组和对照组cTnT的表达进行比较。结果缺血区心肌组织可见明显不规则灶状、片状cTnT缺失区,间质呈阴性表达。在4℃放置．随放置时间延长,正常和缺血心肌组织cTnT阳性表达均有减弱趋势,至14d时均完全缺失。但仅在4℃放置1～7d内,缺血心肌和正常心肌标本之间cTnT阳性反应具有显著性差异。结论cTnT的免疫组化表达用于认定死后4℃放置的尸体是否有死前心肌缺血时．宜在7d以内进行。     

Primary study of vascular endothelial growth factor immunohistochemical staining in the diagnosis of early acute myocardial ischemia

The expression of vascular endothelial growth factor (VEGF) in the model of rat early acute myocardial ischemia was studied by Strept-Avidin-Biotin-Peroxidase Complex (SABC) immunohistochemical staining. After ligating the anterior descending branch of the left coronary artery, an initial rapid (30min) positive expression of VEGF in myocardial ischemic areas was observed, the intensity of positive expression of VEGF increased with the continuation of myocardial ischemia. After 5h infarction, the strongly positive myocytes of SABC-VEGF staining were predominantly limited to perimyocardial infarction areas. No positive expression of VEGF was found in the control group. These findings suggested that SABC-VEGF method could give a sensitive, specific, simple and objective morphologic evidence to the diagnosis of sudden cardiac death caused by acute early myocardial ischemia.     

VEGF在早期心肌梗死死后诊断中的应用

运用免疫组化方法和图像分析与统计学处理系统 ,对人体心脏标本VEGF的表达进行定量研究。结果显示 :心肌梗死组 2 4例心脏标本心肌细胞膜及血管内皮细胞膜均可见棕黄色VEGF强阳性染色 ,有些胞浆也呈阳性 ,尤以心肌梗死灶周围区域心肌细胞为甚 ;在可疑梗死组 2 1例中 ,19例心肌细胞膜及血管内皮细胞膜VEGF强阳性 ,2例为弱阳性 ,未见阴性 ;在正常心脏对照组 16例中 ,仅 1例见心肌细胞膜及血管内皮细胞膜散在棕黄色VEGF弱阳性 ,其余均为阴性。图像分析与统计学处理结果表明 ,对照组VEGF阳性指数 ( 0 3 0± 0 10 )明显低于心肌梗死组 ( 12 46± 3 2 6,P<0 0 1)和可疑梗死组 ( 11 70± 3 5 6,P <0 0 1) ,后两组之间阳性指数无明显差异 (P >0 0 5 )。提示运用免疫组化染色方法结合图像分析处理技术定量检测心肌局部VEGF的表达可望作为因早期心肌缺血导致心脏性猝死死后诊断较为客观的病理形态学指标之一。     

心脏性猝死心肌组织N-Cadherin、Bax表达变化及评价

目的观察心脏性猝死者(SCD)心肌组织的神经性钙粘附蛋白(N-Cadherin)和Bax的表达变化,探讨其法医学意义。方法分别选取心脏性猝死和排除心脏疾病死因的尸检案例心肌组织标本各33例、29为SCD组和对照组。光镜下观察心肌组织病理学改变,检测N-Cadherin和Bax在心肌组织中的表达变化,并进行统计学分析。结果 N-Cadherin在SCD组心肌中表达呈弱阳性,排列紊乱,显著低于正常心肌,正常心肌组织中N-Cadherin呈强阳性表达,细胞间界限明显,排列整齐。Bax在SCD组表达呈阳性,显著高于正常心肌。结论 N-Cadherin和Bax的变化表达对心脏性猝死鉴定有意义。