Diagnosis of myocardial ischemia combining multiphase postmortem CT-angiography, histology, and postmortem biochemistry

The Role of Cardiac Troponins in Postmortem Diagnosis of Myocardial Ischemia: A Systematic Review

Postmortem diagnosis of myocardial ischemia remains a challenge in forensic pathology, as traditional methods like autopsy and histology may not always provide conclusive results. Cardiac troponins, specifically cTnI and cTnT, are well-established biomarkers for myocardial injury in living patients, but their role in postmortem ischemia diagnosis is still under investigation. This systematic review aims to evaluate the role of troponins in diagnosing myocardial ischemia in postmortem cases, focusing on the diagnostic accuracy, sample types, and the influence of the postmortem interval (PMI). A systematic search on PubMed NCBI was conducted to identify studies published between 2000 and 2024 that evaluated the use of cTnI and cTnT in postmortem myocardial ischemia diagnosis. The studies were assessed for their sample types, methods of troponin quantification, sensitivity, specificity, and the impact of PMI on the stability of troponin levels. The review included 13 studies that utilized various sample types, including serum, femoral blood, and pericardial fluid. cTnT was found to be more reliable than cTnI, particularly in pericardial fluid, with shorter PMIs (typically under 48 h) showing higher sensitivity and specificity for myocardial ischemia. Pericardial fluid provided the most consistent results, followed by serum and femoral blood. Studies also highlighted that longer PMIs negatively affected the reliability of troponin measurements due to postmortem degradation. Cardiac troponins, especially cTnT, are valuable biomarkers for diagnosing myocardial ischemia postmortem, particularly when measured in pericardial fluid and within a short PMI. The use of multimarker strategies and the development of standardized cut-off values are needed to improve the accuracy of troponin measurements in forensic pathology. Future research should focus on standardizing diagnostic thresholds, improving assay sensitivity, and exploring new sample types and imaging techniques to enhance postmortem cardiovascular diagnostics.

Postmortem Immunohistochemical Findings in Early Acute Myocardial Infarction: A Systematic Review

The diagnosis of early acute myocardial infarction is of particular importance in forensic practice considering the frequency of sudden cardiac death and the difficulty of positively identifying it through classical histological methods if survival is less than 6 h. This article aims to analyze potential immunohistochemical markers that could be useful in diagnosing acute myocardial infarction within the first 6 h of its onset. We conducted an extensive evaluation of the literature according to the PRISMA guidelines for reporting systematic literature reviews. We searched the Web of Science and PubMed databases from their inception to 2023 using the following keywords: "myocardial infarction" and "immunohistochemistry". Fifteen studies met the inclusion criteria. Immunohistochemical markers as complement factors and CD59, myoglobin, fibrinogen, desmin, tumor necrosis factor alpha (TNF-α), P-38, JNK (Jun N Terminal Kinase), transforming growth factor β1 (TGF-β1), cardiac troponins, fibronectin, H-FABP (heart fatty acid binding protein), dityrosine, fibronectin, CD15, IL-1β, IL-6, IL-15, IL-8, MCP-1, ICAM-1, CD18, and tryptase can be used to identify the first six hours of acute myocardial infarction. These markers are mostly studied in experimental animal models. It is necessary to conduct extensive studies on human myocardial tissue fragments, which will involve the analysis of several immunohistochemical markers and careful analysis of the available data on perimortem events, resuscitation, and postmortem intervals in the context of a uniform laboratory methodology.

Postmortem biochemistry in deaths from ischemic heart disease

Ischemic heart disease (IHD) is one of the leading causes of morbidity and sudden cardiac death worldwide and is an important public health problem. The presence of ischemia in clinical applications can be detected by ECG, biochemical markers, and radiological methods. Myocardial infarction is also frequently encountered in forensic autopsies. Postmortem diagnosis is determined as a result of histopathological examinations and additional exclusionary examinations (toxicology, microbiology, etc.). However, routine histopathological examinations are insufficient, especially when death occurs in the early period of ischemia. It creates a problem for forensic pathologists and forensic medicine specialists in such cases of sudden cardiac death. Postmortem biochemistry is one of the important and promising disciplines in which forensic applications work in order to diagnose these cases correctly. The issue of whether biomarkers used in the diagnosis of myocardial infarction in clinical studies can be used reliably in postmortem cases has been discussed by forensic medicine researchers for some time. This manuscript aims to review and summarize biomarkers belonging to various categories that have been studied in IHD-related deaths, in biological fluids taken at autopsy, or in animal experiments. Our study shows that the postmortem use of biochemical markers in the diagnosis of IHD yields promising results. However, it should not be forgotten that postmortem biochemistry is different from clinical applications due to its dynamics and that the body causes unpredictable changes in markers in the postmortem process. Therefore, comprehensive studies are needed to evaluate the postmortem stability of these markers in different biological fluids, their significance among various causes of death, and whether they are affected by any variable (Cardiopulmonary resuscitation, Postmortem interval, medications, etc.) before they are routinely applied. It is suggested by the authors that the cut-off values of biomarkers whose significance has been proven by these studies should be determined and that they should be used in this way in routine applications.

Coronary artery disease (CAD) extension-derived risk stratification for asymptomatic diabetic patients: usefulness of low-dose coronary computed tomography angiography (CCTA) in detecting high-risk profile patients

BACKGROUND

As one of the most frequent risk factors for cardiovascular disease, type 2 diabetes mellitus (T2DM) is one of the largest causes of death. However, an acute cardiac presentation is not uncommon in diabetic patients, and the current investigative approach remains often inadequate. The aim of our study was to retrospectively stratify the risk of asymptomatic T2DM patients using low-dose 640-slice coronary computed tomography angiography (CCTA).

MATERIALS AND METHODS

CCTA examinations of 62 patients (mean age, 65 years) with previous diagnosis of type 2 diabetes and without cardiac symptoms were analyzed. Image acquisition was performed using a 640-slice CT. Per-patient, per-vessel and per-plaque analyses were performed. Stratification risk was evaluated according to the ESC guidelines. The patients were followed up after 2.21 ± 0.56 years from CCTA examination.

RESULTS

Coronary artery disease (CAD) was found in 58 patients (93.55%) presenting 290 plaques. Analysis of all samples showed severe-to-occlusive atherosclerosis in 24 patients (38.7% of cases). However, over the degree of stenosis, 23 patients were evaluated at high risk considering the extension of CAD. Good agreement was shown by the correlation of CAD extension/risk estimation and MACE incidence, according to a Kaplan-Meier survival analysis (p value = 0.001), with a 7.25-fold increased risk (HR 7.25 CI 2.13-24.7; p value = 0.002).

CONCLUSION

Our study confirms the high capability of CCTA to properly stratify the CV risk of asymptomatic T2DM patients. Its use could be recommended if we consider how current investigative strategies to correctly assess these patients often seem inadequate.

Postmortem Computed Tomography: An Overview for Forensic Nurses Involved in Death Investigation

The traditional invasive autopsy has been considered the "gold standard" for death investigation worldwide. However, this has now been challenged by a new minimally invasive approach that utilizes cross-sectional radiological imaging to investigate the death. Globally, postmortem computed tomography is the most commonly used modality and is becoming increasingly available throughout the world. Forensic nurses working in association with coroners and medical examiners' offices, as well as mass fatality incidents, now need to update their knowledge base to understand these innovative techniques, the advantages and disadvantages to their use, and how they impact on medicolegal death investigation and the care of the deceased and bereaved. Using the example of the coroner system of England and Wales, this article provides a comparison between the traditional invasive autopsy and postmortem radiological alternatives and presents the impact postmortem radiology is now having on death investigation.

Postmortem imaging as a complementary tool for the investigation of cardiac death

In the past 2 decades, modern radiological methods, such as multiple detector computed tomography (MDCT), MDCT-angiography, and cardiac magnetic resonance imaging (MRI) were introduced into postmortem practice for investigation of sudden death (SD), including cases of sudden cardiac death (SCD). In forensic cases, the underlying cause of SD is most frequently cardiovascular with coronary atherosclerotic disease as the leading cause. There are many controversies about the role of postmortem imaging in establishing the cause of death and especially the value of minimally invasive autopsy techniques. This paper discusses the state of the art for postmortem radiological evaluation of the heart compared to classical postmortem examination, especially in cases of SCD. In SCD cases, postmortem CT is helpful to estimate the heart size and to visualize haemopericardium and calcified plaques and valves, as well as to identify and locate cardiovascular devices. Angiographic methods are useful to provide a detailed view of the coronary arteries and to analyse them, especially regarding the extent and location of stenosis and obstruction. In postsurgical cases, it allows verification and documentation of the patency of stents and bypass grafts before opening the body. Postmortem MRI is used to investigate soft tissues such as the myocardium, but images are susceptible to postmortem changes and further work is necessary to increase the understanding of these radiological aspects, especially of the ischemic myocardium. In postsurgery cases, the value of postmortem imaging of the heart is reportedly for the diagnostic and documentation purposes. The implementation of new imaging methods into routine postmortem practice is challenging, as it requires not only an investment in equipment but, more importantly, investment in the expertise of interpreting the images. Once those requirements are implemented, however, they bring great advantages in investigating cases of SCD, as they allow documentation of the body, orientation of sampling for further analyses and gathering of other information that cannot be obtained by conventional autopsy such as a complete visualization of the vascular system using postmortem angiography.Key pointsThere are no established guidelines for the interpretation of postmortem imaging examination of the heartAt present, postmortem imaging methods are considered as less accurate than the autopsy for cardiac deathsPostmortem imaging is useful as a complementary tool for cardiac deathsThere is still a need to validate postmortem imaging in cardiac deaths by comparing with autopsy findings.

The use of cardiac troponin T (cTnT) in the postmortem diagnosis of acute myocardial infarction and sudden cardiac death: A systematic review

Being sudden cardiac death (SCD) and acute myocardial infarction (AMI) frequent occurrences in forensic medicine, extensive research has been published about the use of cardiac troponin T (cTnT) as a potential specific postmortem biochemical marker. However, cTnT has produced uncertain results, leading to the lack of a standardized application in routine postmortem examinations. The present systematic review focuses on the determination of whether cTnT may be considered as a suitable marker for the postmortem diagnosis of AMI and SCD, analysing the literature according to the following criteria: only human experiments, published from 1st January 2001 to 12th April 2018, available in English, on the following databases: (1). Medline/PubMed/MeSH search words: (("heart"[MeSH Terms] OR "cardiac"[All Fields]) AND ("troponin"[MeSH Terms] OR "troponins"[All Fields]) AND forensic[All Fields] AND "postmortem"[All Fields]); (2). Embase, Lilacs and Cochrane Library. 16 full-text articles were included. cTnT has been demonstrated to be elevated in a variety of pathological conditions, not strictly related to cardiac causes, but rather to the severity and extent of myocardial damage from various causes. cTnT levels have been consistently found higher in pericardial fluid than in the peripheral blood. Reviewed studies showed that the most suitable biological sample for cTnT evaluation seems to be pericardial fluid, since it may be less affected by haemolysis of blood. cTnT seems to be quite stable up to a PMI (postmortem interval) smaller than 48h; after this time, a mild time-dependent increase has been demonstrated. CPR seems to have no influence on cTnT values. The postmortem cut-offs differ from clinical ones, and at present no consensus has been reached concerning the postmortem ranges. Further research needs to be carried out in order to establish a common accepted cut-off value for forensic use.

Visualization of Myocardial Infarction in Postmortem Multiphase Computed Tomography Angiography: A Feasibility Study

Recent studies have indicated that multiphase postmortem computed tomography angiography (MPMCTA) allows detection of a pathological enhancement of the myocardium in regions that correlate with the localization of the infarction at histology. The aim of this study was to verify this hypothesis by examining MPMCTA images in cases of myocardial infarction. Therefore, we investigated 10 autopsy cases where death was attributed to myocardial infarction or which showed cardiovascular pathology. As a control group, we selected 10 cases of non-natural (namely, not cardiac) death. The MPMCTA was performed in both groups to ascertain whether a pathological enhancement could be observed. We detected a myocardial enhancement in all cardiac death cases, in the same region that showed infarction at histology. No enhancement was observed in control cases. These results have important implications in the routine management of sudden cardiac death cases. In fact, MPMCTA can not only orient about the cause of death before autopsy, but can especially help to identify affected regions for guiding and improving the sampling for microscopic examination.

Modern post-mortem imaging: an update on recent developments

Modern post-mortem investigations use an increasing number of digital imaging methods, which can be collected under the term "post-mortem imaging". Most methods of forensic imaging are from the radiology field and are therefore techniques that show the interior of the body with technologies such as X-ray or magnetic resonance imaging. To digitally image the surface of the body, other techniques are regularly applied, e.g. three-dimensional (3D) surface scanning (3DSS) or photogrammetry. Today's most frequently used techniques include post-mortem computed tomography (PMCT), post-mortem magnetic resonance imaging (PMMR), post-mortem computed tomographic angiography (PMCTA) and 3DSS or photogrammetry. Each of these methods has specific advantages and limitations. Therefore, the indications for using each method are different. While PMCT gives a rapid overview of the interior of the body and depicts the skeletal system and radiopaque foreign bodies, PMMR allows investigation of soft tissues and parenchymal organs. PMCTA is the method of choice for viewing the vascular system and detecting sources of bleeding. However, none of those radiological methods allow a detailed digital view of the body's surface, which makes 3DSS the best choice for such a purpose. If 3D surface scanners are not available, photogrammetry is an alternative. This review article gives an overview of different imaging techniques and explains their applications, advantages and limitations. We hope it will improve understanding of the methods.

Diagnosis of coronary artery disease using targeted post-mortem computed tomography coronary angiography: a case report

Targeted post-mortem computed tomography (PMCT) combined with coronary angiography has the potential to play a significant role in the investigation of sudden cardiac death. The authors utilized a targeted PMCT coronary angiography in a case involving a 53-year-old man who died from acute myocardial ischemia and cardiac decompensation which may result from coronary artery disease (CAD). The victim collapsed suddenly at work and died soon after arrival to hospital. The body was examined using PMCT and targeted PMCT coronary angiography. The left anterior descending coronary artery exhibited 75%–100% stenosis in the middle segment; however, the distal segment could not be clearly visualized. In addition, the left circumflex and right coronary artery exhibited calcification, atherosclerosis and an area of 50% stenosis. Signs of cardiogenic pulmonary oedema were also identified. The imaging results suggested that this individual had coronary atherosclerosis and probably died from CAD. The autopsy and histological examination revealed acute myocardial ischemia and myocardial scarring, confirming the cause of death while excluding other probabilities. In summary, targeted post-mortem computed tomography angiography (PMCTA) can visualize the arteries and estimate the degree of principal pathological changes. This method is a simple, reliable and sensitive technique for identifying the presence of coronary atherosclerosis. It is a valuable post-mortem forensic imaging method and should be recommended in the investigation of suspicious cardiac deaths.