Abstract:
Introduction: The objective was to evaluate diagnostic accuracy of high sensitivity C-reactive protein (hS CRP), Interleukin-18 (IL-18), Tumor Necrosis Factor-alpha (TNF-alpha), Interleukin-10 (IL- 10), IL-18/IL- 10 ratio and their serum cut off values for identification of Premature Coronary Artery Disease (PCAD) patients.
Method: It was a diagnostic validation case-control study carried out at the Clinical Pathology Laboratories of the Army Medical College, Rawalpindi, Pakistan, from May, 2013 to Jan, 2014. Two hundred and fifty subjects aged < 45 years scheduled to undergo coronary angiography were consecutively screened. Out of these ninetyeight patients with > 70% stenosis, in at least one coronary vessel on angiography, were labeled to have PCAD. An equal number of angio-negative subjects were taken as controls from the study group. Serum IL- 10, IL- 18 and TNF alpha were measured using Enzyme Linked Immuno-sorbent Assay (ELISA), hS CRP on Immulite 1000 and serum cholesterol, Triglycerides and High Density Lipoprotein (HDL) by colorimetric methods. Statistical analysis was done using SPSS-17 and MedCalc software.
Results: Total 196 subjects consisting of 98 PCAD patients and 98 angio-negative controls participated in the study. Mean ± SD age of PCAD patients was 40.7 ± 4.23yrs (89 males and 9 females) while in controls it was 35.1 ± 7.55yrs (93 males and 5 females). Serum hS CRP had highest area under curve AUC (95% confidence interval) of 0.936 (0.89- 0.97) while AUC (95% CI) of IL-18, TNF alpha and IL-10 were 0.853 (0.79-0.90), 0.731 (0.659-0.796) and 0.574 (0.497- 0.649) respectively. Sensitivity-specificity of hS CRP and IL-18 at cut off value of 3.18 pg/ml and 200pg/ml were 86%-91% and 77%-81% respectively while that of IL-18/IL-10 ratio and IL-10 at cut off values > 138.9 and > 0.3pg/ml were 68-64% and 20-100% respectively. Significant correlation was observed between hS CRP (p < 0.01), IL- 18 (p < 0.01) and TNF alpha (p < 0.05).
Conclusion: hS CRP and IL-18 have the best diagnostic potential among the cytokines for detection of PCAD with high sensitivity and specificity. IL-18/IL-10 ratio had moderate significance in the diagnosis of PCAD although it correlated well with the disease burden. IL-10 had 100% specificity highlighting its role in the diagnosis of the disease but its low sensitivity is a limiting factor. Thus, hS CRP and IL-18 are promising potential biochemical parameters aiding in the clinical diagnosis of Premature Coronary Artery Disease.
