Heart- type Fatty Acid Binding protein in Early Detection of Acute Myocardial Infarction Comparison With CK-MB, Troponin I and Myoglobin .

Abstract

Background: Early diagnosis and therapeutic intervention can improve the outcome of acute myocardial infarction (AMI). However, there are no satisfactory cardiac biomarkers for the diagnosis of AMI within 6 hours of onset of symptoms. Among novel biochemical markers of AMI, heart-type fatty acid binding protein (H-FABP) is of particular interest. Aim: The study aimed to investigate whether H-FABP measurement provides additional diagnostic value to that of conventional cardiac markers in AMI within first 6 hours after the onset of symptoms. Materials and methods: A total of 120 patients presenting with acute chest pain within 6 hours of onset, suggestive of AMI were included in the present study according to the inclusion and exclusion criteria. In all the cases and controls, complete clinical history, ECG, echocardiography and other routine investigation findings were noted. Serum H FABP concentration was measured by immunoturbidimetric method, serum troponin I and myoglobin concentrations were measured by chemiluminescence immunoassay and serum CK-MB activity was estimated by immuno-inhibition method. Diagnosis of AMI was done according to the European Society of Cardiology/ American College of Cardiology Committee (ESC/ACCC) Criteria. 60 cases were diagnosed as having AMI cases and remaining 60 cases were age and sex matched non-cardiac chest pain controls. The cases and controls were further divided into 2 subgroups depending on the time since onset of chest pain as those subjects within 3 hours and those between 3-6 hours of onset of chest pain. Statistical Analysis: Data was presented as mean ± SD values. Differences between means of two groups were assessed by Student t-test. Sensitivity, Specificity, Positive xvi

predictive value, Negative predictive values were calculated and ROC curve analysis was done to assess the diagnostic validity of each study parameter. Results: The serum mean levels of H-FABP, CK-MB, troponin I, and myoglobin were significantly higher (p > 0.01) in AMI cases when compared to that of non-AMI controls in both 0 – 3 hrs (40.4 ± 56.3, 26.2 ± 19.2, 5.9 ± 16.2, 364.9 ± 363.9 vs 4.7 ± 7.3, 18.6 ± 9.5, 0.0048 ± 0.0077, 55.7 ± 53.4 respectively) and 3 – 6 hrs (76.3 ± 56.1, 36.9 ± 48.9, 8.5 ± 16.9, 584.5 ± 393.9 vs 6.7 ± 8.6, 25 ± 10.1, 0.0087 ± 0.0079, 90.8 ± 74.2 respectively) groups. The sensitivity, specificity, positive and negative predictive values of H-FABP (92.3%, 88.5%, 88.9%, 92.0% in 0-3 hr group; 94.1%, 79.4%, 82.1%, 93.1% in 3-6 hr group, respectively) were significantly greater than CK-MB (23.1%, 61.5%, 37.5%, 44.5% in 0-3 hr group; 52.9%, 58.8%, 56.3%, 55.6% in 3-6 hrs group, respectively) and myoglobin (73.1%, 76.9%, 76.0%, 74.1% in 0-3 hrs group; 88.2%, 70.6%, 75.0%, 85.7% in 3-6 hrs group, respectively) but were lesser than Troponin I (96.2%, 100%, 100%, 96.3% in 0-3 hrs group; 100%, 100%, 100%, 100% in 3-6 hrs group, respectively) in patients with suspected AMI in both within 3 hours and 3 – 6 hours groups. Receiver Operating Characteristic (ROC) curves demonstrated greatest diagnostic ability for Troponin I (AUC = 0.997 & P = 0.000 in 0-3 hr group; AUC = 0.982 & P = 0.000 in 3-6 hrs group) followed by H-FABP (AUC = 0.886 & P = 0.000 in 0-3 hrs group; AUC = 0.911 & P = 0.000 in 3-6 hrs group), myoglobin (AUC = 0.841 & P = 0.001 in 0-3 hrs group; AUC = 0.860 & P = 0.000 in 3-6 hrs group) and CK-MB (AUC = 0.640 & P = 0.163 in 0-3 hrs group; AUC = 0.616 & P = 0.177 in 3-6 hrs group) within 3 hrs and 3 – 6 hrs after the onset of chest pain. xvii

Conclusion: The diagnostic value of H-FABP is greater than CK-MB and myoglobin but slightly lesser than troponin I for the early diagnosis of AMI within first 6 hours of chest pain. H-FABP can be used as an additional diagnostic tool for the early diagnosis of AMI along with troponin I