Sudan Journal of Medical Sciences Volume 15, Issue no. 3, DOI 10.18502/sjms.v15i3.7746 Production and Hosting by Knowledge E Research Article Evaluation of the Efficiency of N-terminal Pro-B-type Natriuretic Peptide for Diagnosis of Acute Myocardial Infarction Abuagla M. Dafalla1, Leena A. Dafalla1, ShamsEldein M. Ahmed1, Yousif A. Mohammed2, Adam D. Abakar3, Wed elbahar H.Aballah4, Elhadi A. Ahmed5, and GadAllah Modawe6 1Department of Clinical Chemistry, Faculty of Medical Laboratory Sciences, University of Gezira, Sudan 2National Cancer Institute, University of Gezira, Sudan 3Department of Medical Parasitology, Faculty of Medical Laboratory Sciences, University of Gezira, Sudan 4Department of hematology and immunohematology Faculty of Medical Laboratory Sciences, Managil University of Science and Technology Sudan 5Department of Medical Microbiology, Faculty of Medical Laboratory Sciences, University of Gezira, Sudan 6Department of Biochemistry, Faculty of Medicine and Health Sciences, Omdurman Islamic University, Omdurman, Sudan Abstract Background: Cardiac diseases are one of the major causes of death worldwide with increasing incidence rate per year, particularly in developing countries such as Sudan owing to urbanization and changing lifestyle. Myocardial infarction is a consequence of the imbalance between the heart blood supply and the required heart cell; this disorder leads to necrosis of myocardium and may cause death. It could be diagnosed by at least two of the following criteria: chest pain, electrocardiography (ECG) elevation, and levels on cardiac biomarkers. This study aimed to evaluate the efficiency of N-terminal pro- B-type natriuretic peptide (NTproBNP) for the diagnosis of acute myocardial infarction (AMI). Methods: This analytical case–control hospital-based study was conducted on total of 70 individuals, of which 40 participants were suspected of or diagnosed with AMI,while30 healthy subjects were included as a control group. Three ml of venous blood were collected in lithium heparin containers. Troponin I (TnI) as a cardiac biomarker was measured by TOSOH AIA-360,while theNTproBNP level was detected using I-Chroma II. Personal and clinical data were collected directly from each participant usinga predesigned questionnaire. Results: A significant increase in the TnI level (mean: 13.13 ± 18.9ng/ml) and NTproBNP (mean: 5756.5 ± 8378.2pg/mL) in AMI patients were detected when compared with control mean (0.02 ± 0.00ng/ml and 57.8 ± 42.32pg/mL, respectively). Conclusions: NTproBNP gave a high sensitivity (87.5%), specificity (100%), positive predictive value (100%), and negative predictive value (85.7%) in the diagnosis of AMI when compared with another cardiac biomarker such as TnI. Keywords: acute myocardial infarction, NTproBNP, troponin I, Medani Heart Center, Sudan How to cite this article: Abuagla M. Dafalla, Leena A. Dafalla, ShamsEldein M. Ahmed, Yousif A. Mohammed, Adam D. Abakar, Wed elbahar H.Aballah, Elhadi A. Ahmed, and GadAllah Modawe (2020) “Evaluation of the Efficiency of N-terminal Pro-B-type Natriuretic Peptide for Diagnosis of Acute Myocardial Infarction,” Sudan Journal of Medical Sciences, vol. 15, issue no. 3, pages 249–258. DOI 10.18502/sjms.v15i3.7746 Page 249 Corresponding Author: GadAllah Modawe; email: gadobio77@hotmail.com Received 20 June 2020 Accepted 15 August 2020 Published 30 September 2020 Production and Hosting by Knowledge E Abuagla M. Dafalla et al. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited. Editor-in-Chief: Prof. Mohammad A. M. Ibnouf http://www.knowledgee.com mailto:gadobio77@hotmail.com https://creativecommons.org/licenses/by/4.0/ https://creativecommons.org/licenses/by/4.0/ Sudan Journal of Medical Sciences Abuagla M. Dafalla et al 1. Introduction A cardiac disease refers to any disorder that affects the heart function by either min- imizing or eliminating the heart output [1]. Cardiac diseases are caused either by structural heart disorder or myocardium abnormalities such as myocardial infarction (MI) [2]. An acute myocardial infarction (AMI) is a consequence of the imbalance between the heart blood supply and the required heart cell. This disorder leads to necrosis of the myocardium and may even cause death [1].MI is the most common cause of death worldwide [3, 4]. The frequency of MI has increased over the last few decades throughout several states of Sudan, which may be due to the increase in the prevalence of risk factors such as underlying diseases and habits [5]. The symptoms of a cardiac disease include chest pain and dyspnea due to the reduction of oxygen in myocardial cells, whichis considered as a cardinal indication of AMI [6], and palpitations due to the increase in oxygen demand. Other symptoms include headache and limb weakness [7]. The diagnosis of cardiac diseases depends on the history, risk factor, clinical examination, symptoms, laboratory investigation, chest radiology, electrocardiography (ECG), and echocardiography (Echo) [8]. Moreover, AMI can be diagnosed by at least two of the following three criteria; first, typical symptoms such as a history of chest pain; second, changes on the ECG, and third, elevation on cardiac biomarkers [9]. The latter are specific elements produced by the cardiac cells and increase in cardiac disorders. Cardiac biomarkers include troponin, creatine kinase (CK), myoglobin [10, 11], and brain natriuretic peptides (BNPs) [12].Cardiac troponin is a muscle-regulatory protein produced by a muscular cell present in skeletal and heart muscles. Troponins are generally categorized into three types; troponin T, troponin I (TnI), and troponin C [13]. For cardiac biomarkers, TnI is more sensitive and specific than others troponins [14]. In AMI, the TnI rises in plasma after 4–8 hr of the onset of the symptoms, reaches the peak at 12–24 hr, and then returns to normal within 7–10 days of AMI [15]. CK, on the other hand, is an enzyme consisting of two protein subunits:muscle protein (M) and brain protein (B), and depending on the constituent, CK has three isoenzymes; CKBB, CKMM, and CKMB [16].While CKBB is more abundant in the brain cells, CKMM is more abundant in the muscular cells and CKMB in the cardiac muscles [17]. CKMB is more sensitive and specific for the diagnosis of cardiac disease than CKMM and CKBB [15].CKMB level in plasma increases after 4-8 hours of MI and reaches the peak at 12 – 24 hours then return to the normal level within 2 – 3 days (16). BNPs are polypeptides produced by myocardium in response to the increased wall stress due to an increase in volume or pressure of blood, to reduce intravascular volume DOI 10.18502/sjms.v15i3.7746 Page 250 Sudan Journal of Medical Sciences Abuagla M. Dafalla et al by diuretics, vasopressin, and suppuration the sense of thirst (16). BNPs are secreted as pro-hormone then activated by reacting with protease enzyme to cleave it into active form BNP and inactive form NTproBNP(18). In the case of cardiac disease, both BNPs are elevated, thus, measurement of plasma BNP and /or NTproBNP is a useful indicator for cardiac diseases (16). The objective of the present study was to evaluate the efficiency of N-terminal pro-B-type natriuretic peptide (NTproBNP) for the diagnosis of AMI. 2. Materials and Methods This analytical case-control hospital-based study aimed to evaluate the efficiency of NTproBNP for the diagnosis of AMI. The study was conducted in Medani Heart Center, Sudan. A purposive sample was collected from patients with AMI attending Medani Heart Center from April 2018 to June 2019. A total of 70 individuals participated in this study, 40 were AMI cases and 30 were healthy individual as a control group. AMI cases were included according to the final diagnoses by Medani Heart Center physicians. AMI patients with renal failure or Biotin treatment were excluded. The control group was non-smokers, non- obese, normotensive, non-diabetic and have no history of renal or cardiac diseases. The demographic data were collected from each participant after final diagnosis using a questionnaire included clinical remarks such as AMI symptoms, ECG, Echo and risk factors. 2.1. Ethical consderion Permission to carry out the study was obtained from the College of Graduate Studies, Faculty of Medical Laboratory Sciences, University of Gezira and Ministry of Health, Sudan. All enrolled patients were informed about the purpose of the study before collection of specimens and consents for participation were taken. 2.2. Data variable, collection and criteria Sex, age (Year) - TnI (ng/ml) - NTProBNP (pg/ml) – Risk factors - Clinical Diagnosis - Echocardiogram – Electrocardiogram were the variables used and also the data were collected using laboratory analysis, doctor’s report, other findings and data collection form. Restricted criteria for eligibility of case and control (inclusion and exclusion criteria) DOI 10.18502/sjms.v15i3.7746 Page 251 Sudan Journal of Medical Sciences Abuagla M. Dafalla et al was followed to reduce sources of bias.A purposive sample was used to determine the sample size because there is no previous prevalence for AMI in Sudan. 2.3. Measurement of cardiac biomarkers Three ml of blood specimen from each participant were collected in lithium heparin anticoagulant tubes for laboratory analysis; plasma was separated into two new plain containers and examined within 2 hrs. The laboratory work was done in Medani Heart Center and Department of Clinical Chemistry, Faculty of Medical Laboratory Sciences, University of Gezira. TOSOH AIA-360 automated machine (Germany) was used to measure TnI levels while I-Chroma II immunofluorescence system (Korea) was used to measure NTproBNP levels. 3. Data analysis Collected data were analyzed by using suitable statistic software including SPSS com- puter version 22 and Medical calculator program version 16. Calculation of sensitivity, specificity, positive predictive value and the negative predictive value was done by these equations: Sensitivity = TP/TP+FN*100. Specificity = TN/TNFP*100. Positive predictive value = TP/TP+FP*100. Negative predictive value = TN/TN+FN*100. TP: true positive - FP: false positive - TN: true negative -FN: false negative. 4. Results 4.1. Demographics of AMI subjects This study enrolled 40 patients with AMI, among whom 62.5% were male, 45% diabetic, 40% hypertensive, 25% smokers, 25% obese,97.5% has no history of cardiac diseases. Patients with age group above 59 years constituted 50% as shown in Table (1). DOI 10.18502/sjms.v15i3.7746 Page 252 Sudan Journal of Medical Sciences Abuagla M. Dafalla et al 4.2. Performance of NTproBNP and TnI Total positive results of NTproBNP and TnI were 35/40 and 32/40, respectively. Sensi- tivity, specificity, positive and negative predictive values of NTproBNP and TnI of AMI patients and control were shown in Table 2. 4.3. Biomarkers levels Plasma levels of NTproBNP and TnI were significantly detected among AMI patients; the level of NTproBNP ranged from15 to 30000 with mean of 5756.5 pg/ml while TnI recorded from 0.015 to 50 with mean of 13.1 ng/ml(Table 3). 4.4. Biomarkers results related to ECG and Echo Positive ECG was recorded with 26 patients of 32 TnI positive and with 27 patients of 35 NTproBNP positive. While, less sensitively positive Echo were obtained with 20 patients of 32 TnI positive, and with 21 patients of 35 NTproBNP positive Table 4.Measuring of NTproBNP and TnI results using Area Under the Curve AUC according to ECG as the gold standard method shown in Table 5, Figure (1). TABLE 1: Characteristics of acute myocardial infarction patients. N % Sex Male 25 62.5 Female 15 37.5 Age/year <59 20 50 <59 20 50 Diabetes Diabetic 18 45 Non-diabetic 22 55 Chest pain Yes 40 100 No 0 0 Hypertension Yes 16 40 No 24 60 Smoking Yes 10 25 No 30 75 History of cardiac disease Yes 1 2.5 No 39 97.5 ECG STEMI 32 80 Non-STEMI 8 20 Obesity Obese 10 25 Non-Obese 30 75 DOI 10.18502/sjms.v15i3.7746 Page 253 Sudan Journal of Medical Sciences Abuagla M. Dafalla et al TABLE 2: Performances of NTproBNP and TroponinIamong cases and control. Biomarker Case Control Sensitivity % Specificity % Positive predictive Value% Negative predictive Value% NTproBNP Positive 35 0 87.5 100 100 85.7 Negative 5 30 TnI Positive 32 0 80 100 100 78.9 Negative 8 30 TABLE 3: Levels of NTproBNP (pg/ml)and Troponin I (ng/ml) among40 cases of AMI patients and 30 control subjects NO Mean SD p.value NTproBNP Case 40 5756.5 8378.2 0.00 Control 30 57.8 42.3 TnI Case 40 13.1 18.9 0.00 Control 30 0.02 0.000 TABLE 4: Relationship between the results of Troponin I and NTproBNP with ECG and Echo TnI /NTproBNP ECG Total Positive Negative NTproBNP Positive 27 8 35 Negative 5 0 5 TnI Positive 26 6 32 Negative 6 2 8 Echo Positive Negative NTproBNP Positive 21 14 35 Negative 3 2 5 TnI Positive 20 12 32 Negative 4 4 8 TABLE 5: Therea under ROC curve for NTproBNP and TnI according to ECG as a gold standard method. Variable 1 TnI Variable 2 NTproBNP Classification variable ECG Sample size 70 Positive group 𝑎 32 (45.71%) Negative group 𝑏 38 (54.29%) Area under the ROC curve for TnI 0.827 Area under the ROC curve for NTproBNP 0.817 DOI 10.18502/sjms.v15i3.7746 Page 254 Sudan Journal of Medical Sciences Abuagla M. Dafalla et al 5. Discussion MI is a consequence of the imbalance between heart blood supply and the heart cell needs; this disorder leads to necrosis of the myocardium and may cause death (1). It is diagnosed by at least two of three of the following criteria; firstly, chest pain, secondly changes on the ECG, and thirdly elevation on cardiac biomarkers (9). From this study, chest pain was recorded with all AMI patients, male patients more frequently than females with a percentage of 62%.On the other hand, the age group above and below 59 years were equally stated, these findings were in agreement with a study done by Ahmed in Sudan(19).Diabetes mellitus and hypertension as risk factors in the current study were observed in 45 % and 40% from AMI cases, this threat could be decreased by routine follow up of patients and establishment of specialized centers for care. From the results, smokers were less than non-smokers; this was in concord with a similar study(20) and in contrast with Elkhader et al(21).According to the clinical diagnosis, 80% of AMI patients were ST-Elevation Myocardial Infarction (STEMI), this result was near to the percentage concluded byAbdallah in Sudan(22).In the current study, each of TnI and NTproBNP had significant values in the diagnosis of AMI in studied patients, same findings were reported in the UK(23) and USA(24), however, in our study 12.5% (5/40) and 20% (8//40) of suspected cases gave insignificant concentrations for NTproBNP and TnI,respectively.NTproBNP values were highly sensitive when compared withTnI according to ECG and Echo, this result differs with those done byDimiati et al. in Indonesia who foundTnI was more sensitive(25).The rea under ROC curve for NTproBNP was (0.817) and for TnI equal (0.827) according to ECG as a gold standard method, this indicates that each of the studied biomarkers had a good performance in the diagnosis of AMI. 6. Conclusions The NTproBNP had high sensitivity, specificity, positive predictive value and negative predictive value when compared with TnI in the diagnosis of AMI. Funding This research has been fully financed by the German Academic Exchange Service (DAAD) In-Country Scholarship Program Sudan, 2016 (57298697). DOI 10.18502/sjms.v15i3.7746 Page 255 Sudan Journal of Medical Sciences Abuagla M. Dafalla et al Acknowledgments I am grateful to the help and support offered by the staff of Wad Medani Cardiac Center for helping me in my practical (lab and Archive department) and staff of laboratory of Professor BakryYousif. Especial thanks to laboratory specialist Mohamed Snhory.I owe a deep debt of gratitude to Dr. Mohamed Hamzaand laboratory specialist (Sidig Said and Omer ELtigani) for helping me to obtain NTproBNP reagents. I am very grateful to the patients and healthy peoples who participated in the study from Gezira state. References [1] Danish, M. I. 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DOI 10.18502/sjms.v15i3.7746 Page 258 Introduction Materials and Methods Ethical consderion Data variable, collection and criteria Measurement of cardiac biomarkers Data analysis Results Demographics of AMI subjects Performance of NTproBNP and TnI Biomarkers levels Biomarkers results related to ECG and Echo Discussion Conclusions Funding Acknowledgments References