Research Article
Cardiac and coronary artery study on sudden death cases in Hospital Canselor Tuanku Muhriz
Soo Shih Sheng 1, Siti Balkis Budin 1,3 , Ismarulyusda Ishak 1,2 , Faridah Mohd Nor 4 and Nur Najmi Mohamad Anuar 1,2 *
1 Biomedical Science Programme, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.
2 Center for Toxicology and Health Risk Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.
3Center for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.
4Forensic Unit, Pathology Department, Faculty of Medicine, Hospital Canselor Tuanku Muhriz UKM, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia.
* Correspondence
Nur Najmi Mohamad Anuar
Biomedical Science Programme, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.
nurnajmi@ukm.edu.my
Tel: +603-9289 7134
Received: 4 January 2021; Revised: 5 February 2021; Accepted: 12 March 2021; Published: 14 April 2021
DOI: https://doi.org/10.28916/lsmb.5.1.2021.77
ABSTRACT
Background: Sudden death (SD) is defined as an unexpected natural death within an hour onset of symptoms or unwitnessed death that occurs within 24 hours, which accounts for most cardiovascular deaths in Malaysia. This study aimed to evaluate the extent of histopathological changes in the heart and to study the demographic trend in SD cases in Kuala Lumpur, Malaysia. Methods: Specimens from all SD cases were received from 2017 to 2018 by the Forensic Unit, Hospital Canselor Tuanku Mukhriz (HCTM) were studied. The specimens were the left ventricular myocardium and left anterior descending artery (LAD), which were fixed in 10% formalin with haematoxylin and eosin staining. The tissues were graded histologically based on changes such as arterial occlusion, myocardial infarction, and/or thrombus formation. Results: Out of 545 medicolegal deaths, only 25 cases (4.6%) had samples available for analysis. Among these 25 patients, 24 (96%) were male patients and only one (4%) was a female patient. The available samples were from patients aged between 30 to 79 years old. In terms of ethinicity, Malays (40%) were the most numerous, followed by patients of Chinese and Indian ethnicities.The majority of the SD cases had a body mass index (BMI) that ranged between underweight (56%) and obese (40%). Besides, there were 10 (40%) cases of coronary artery with atheroma and 15 (60%) cases of myocardial infarction. The most common presentation of atherosclerosis was grade III and IV, and acute MI was the most common presentation at death, followed by healed infarcts and old infarcts. Discussion and Conclusion: Our findings reflect worsening risk factor levels in cardiovascular diseases, compounded by demographic trends. Further studies on biomarkers specific for cardiac diseases are warranted to understand imminent sudden cardiac death.
Keywords: Autopsy; cardiac death; coronary artery; forensic pathology; sudden death
INTRODUCTION
Sudden death (SD) is defined as natural death that occurs within 24 hours, in the presence or absence of onset of symptoms. Sudden cardiac death (SCD) is defined as an unexpected death that occurs within one hour, with or without the onset of symptoms (Nisha et al., 2011). Epidemiological reports have proven that both types of deaths are strongly associated with age, sex, lifestyle, ethnicity, and family medical history (Mozaffarian et al., 2015). Hence, demographic factors should be taken into consideration in an autopsy to assist in the determination of the cause of death.
Several factors have been linked with the aetiology of SD, and cardiac disease is the major cause of incidence worldwide (Tezcan et al., 2003). Several diseases are related to cardiac abnormalities such as myocardial infarction (MI), cardiomyopathy, myocarditis and congenital disabilities. MI is known as an irreversible necrosis of myocardial tissue resulting from decreased blood flow in arteries, which leads to an insufficient oxygen supply. In Malaysia MI is one of the leading causes of death, accounting for 20.1 % of all deaths (Chai et al., 2015). The risk factors of MI depend on age, sex, lifestyle, ethnicity and family history. With increased age, there is a higher risk of having MI. It was reported that men are at more at risk of MI at the age of 65, whilefor women, it is 71.8 years old (Mozaffarian et al., 2015). This is due to physiological changes in women, such as hormonal changes, unhealthy lifestyle, and reduction of metabolic rate (Hemingway et al., 2001; Wong et al., 2012).
Besides age, sex plays a vital role in the pathogenesis of MI. A report by the National Centre for Health Statistics in 2012 stated that readmission due to cardiac disease in women was higher than in men at the age of 65 and above (Statistics, 2012). Women are believed to have a higher risk of MI compared to men, as women will experience endothelial dysfunction and deposition of fat in the blood vessel during menopause. Moreover, reduced estrogen level is believed to be the primary cause of MI in menopausal females (Mozaffarian et al., 2015). The function of estrogen is not only to regulate prostaglandin production, but also increases vascular permeability (Williams, 1978) and induces nitric oxide production, which will promote vasodilation. According to a study by INTERHEART, the Indian population in Asia has a higher risk of cardiac disease at a young age compared to other races in Middle and South America. This is because they share a history of diabetes, which is closely linked to the aetiology of cardiac diseases (Jha et al., 2003; Rodriguez et al., 2014).
MATERIALS AND METHODS
The study was conducted at the Forensic Unit of Hospital Canselor Tuanku Muhriz (HCTM), Kuala Lumpur from 2017 to 2018. A cross sectional study design was used by using retrospective data. An ethics approval (JEP-2018-062) was granted by the UKM Ethical Committee.
The inclusion criterion was all subjects with cardiac abnormalities. Infants, children, other causes of death, and incomplete postmortem reports were excluded. The age range of subjects was 30-79 years old, based on the retrospective data. The BMI classification was based on a previous study done in Malaysia, which divided subjects into 4 categories: <18.5kg – Underweight; 18.5-22.9 kg – Normal; 23-27.4kg - Overweight; and 27.5 - Obese (Azhari et al., 2017). There were 25 cases in total of heart and vessel samples of the left anterior descending artery (LAD) and left ventricular myocardium (LV).
Histopathological analysis
The sampled were fixed in 10% formalin, and underwent tissue processing using an automated tissue processor (Leica TP1020, Germany), which comprised of three processes: 1) dehydration, 2) clearing, and 3) impregnation. The processed tissue samples were then embedded in paraffin wax to form blocks (Leica EG1160, Germany) that were later sectioned using a rotary microtome (Leica RM2135, Germany). The sectioned blocks of tissue were then attached to slides and proceeded to haematoxylin and eosin (H&E) staining in order to visualize the morphology of the tissue. All histological sections were examined under a microscope for the presence of atheroma, MI and thrombus.
Atherosclerosis was graded based on the criteria by Siraj Ahmed & Begum (2013). The classification was based on the percentage of occlusion of plaque covering the artery lumen, subdivided into 5 different grades as shown in Table 1. MI was classified as acute, healing and old infarcts (Arai, 2015). Acute myocardial infarction (AMI) was featured by the absence of nuclei due to karyolysis and inflammatory cell infiltration. Meanwhile, fibroblasts and macrophages were present in healing infarcts, while fibrosis and fibroblast were predominant in old infarcts.
Table 1: Atherosclerosis grading system based on percentage occlusion of plaque
|
Grade |
Occlusion(%) |
|
Grade 0 |
Normal |
|
Grade I |
1 – 25 |
|
Grade II |
26 – 50 |
|
Grade III |
51 – 75 |
|
Grade IV |
76 – 100 |
Statistical analysis
Statistical analysis was performed using SPSS Version 22.0. The tests used were descriptive analysis and Spearman correlation with p≤0.05 considered significant.
RESULTS
The collected data exhibited 1740 deaths in 12 months, which comprised of 545 (31.3%) medicolegal and 1195 (68.7%) non-medicolegal cases. Of the 545 cases, 138 SD and 55 (40%) had cardiac abnormalities. After considering inclusion and exclusion factor, 25 cases between the age range of 30 to 79 years old were sampled. It was observed that the number of SD cases was the highest among the 60 to 69 years old subjects (n = 9), and this was followed by a decreasing trend in the other age groups: 40 to 49 (n = 6) and 50 to 59 (n = 6), 70 to 79 (n = 3) and 30 to 39 years of age (n = 1) (Table 2). It was evident that the highest risk was exhibited by the 60 to 69 years old age group compared to the 70 to 79 years old age group, probably because of the good management in hospitals that the older subjects were given.
Table 2: Age and sex distribution in sudden death cases
|
Age(years) |
Male |
Female |
Total |
|
30 – 39 |
1 |
0 |
1 |
|
40 – 49 |
5 |
1 |
6 |
|
50 – 59 |
6 |
0 |
6 |
|
60 – 69 |
9 |
0 |
9 |
|
70 – 79 |
3 |
0 |
3 |
|
Total |
24 (96%) |
1 (4%) |
25 (100%) |
Interestingly, one subject (n = 1) in the 50 to 59 years old age group had a normal BMI, but this age group also had the highest number of both overweight and obese subjects (n = 4) (Table 3).
Table 3: Age and BMI in sudden death cases
|
Age(years) |
Normal (18.5–22.9) |
Overweight (>23–7.4) |
Obese (>27.5) |
|
30 – 39 |
0 |
4 |
2 |
|
40 – 49 |
0 |
3 |
3 |
|
50 – 59 |
1 |
4 |
4 |
|
60 – 69 |
0 |
3 |
0 |
|
70 – 79 |
0 |
0 |
1 |
|
Total |
1 (4%) |
14 (56%) |
10 (40%) |
Malaysia has three main ethnic communities i.e., Malays, Chinese and Indians. By ethnicity, the Malays (n = 10) had the highest cardiac case-fatalities, followed by Chinese (n = 8), other ethnicities (n = 6) and Indians (n = 1). This could be due to the Malays and Chinese being the dominant populations in Malaysia, thus proportionately contributing to the higher numbers.
Table 4: Sudden cardiac death by ethnicity
|
Ethnicity |
Number of cases |
|
Malay |
10 |
|
Chinese |
8 |
|
Indian |
|
