Résumé
The scope of this study was to evaluate the significance of serum paraoxonase [PON] assay in diagnosing coronary artery disease [CAD] and to investigate its reliability in determining the severity and progression of CAD. Furthermore, the diagnostic reliability of this marker was compared to that of routinely used conventional lipid parameters and apolipoproteins A1 and B. This study included 65 male patients suffering from anginal pain and were subjected to coronary angiography in addition to 20 age matched healthy males. The coronary angiography of 20 angina patients revealed normal coronary arteries and they were considered as pathological controls. The remaining 45 patients were proved to have atherosclerotic CAD, 15 of them had single vessel affected [SVD], 14 had double vessels affected [DVD] and 16 had multiple vessels affected [MVD]. Routine lipid profile, apolipoprotein A1 [apo-A1], apolipoprotein B [apoB] and serum PON were assayed in all subjects. Serum PON was assayed using a prepared solid phase competitive enzyme immunoassay. Apolipoprotein A1 [apo-A1] and apoB were assayed on the Olympus AU400 system by an immunoturbidimetric endpoint method. Routine lipid parameters were measured on the Synchron CX7 autoanalyzer. Our results showed that all angina subjects were similarly exposed to hypertension, diabetes mellitus and smoking as risk factors for CAD. Serum lipid profile did not vary significantly among the subjects suffering from chest pain. However, when compared to healthy controls, patients with anginal pain showed significantly lowered HDL-C and apo-A1 serum levels and significantly higher atherosclerotic, risk ratio. Moreover, all assayed lipid parameters failed to show any significant difference between different subgroups of CAD patients. In the present study, serum PON levels decreased progressively with the progression of CAD being significantly lower in MVD and DVD subgroups than in SVD. Serum PON levels correlated significantly with nearly all angiographic parameters. Moreover, serum PON had a diagnostic sensitivity, specificity and efficacy of 95.6%, 93.2% and 94.6%, respectively at a cut-off level of 91.0 microg/mL in detecting CAD patients when compared to controls and was proved to be the best discriminating marker for CAD using the multiple regression analysis. As regards apo-A1, the diagnostic efficacy was 67.6% at a cutoff level of 120 mg/dL and it was the second discriminating parameter that could differentiate CAD patients from healthy subjects using the multiple regression analysis and showed a significant correlation with some angiographic parameters and with PON. Finally, routine lipid profile parameters and apoB did not show any significant correlation neither with PON nor with the angiographic parameters. In conclusion, the current study revealed that serum PON was the best predictive marker for CAD risk and the best diagnostic tool for severity for atherosclerotic CAD