Correlation Of Platelet With Clinical Studies In Patients With Coronary Artery Disease Pre And Post Coronary Artery Surgery

80 patients with angina were studied preoperatively with measurements of ⁵¹Cr platelet survival (PS), plasma PF4 and βTG (RIA), platelet aggregates and platelet count. Clinical data was recorded prospectively. 58 patients were restudied a mean of 34 weeks postoperatively, 44 of whom entered a double blind randomized trial of sulphinpyrazone.

Mean preoperative PF4 and βTG were elevated above normal values (PF4 14 vs 8ng/ml, βTG 54 vs 32ng/ml) and the mean PS shortened (150 vs 174hrs). These tests returned towards normal postoperatively (PF4 10ng/ml, βTG 39ng/ml and PS 186hrs). This trend is partly due to a significant change in βTG, PF4 and PS in patients treated with sulphinpyrazone.

A significant negative correlation was detected between platelet count and angina grade (r = -0.30, p< 0.001), number of previous transmural myocardial infarctions (r = -0.36, p< 0.001) and angiographic grading of severity of coronary artery disease (r = -0.28, p<0.05). No other significant correlation of platelet studies with coronary artery disease (CAD) status was detected. There was however an association between elevated PF4 and βTG and shortened PS in the 4 postoperative patients with peripheral vascular disease (PVD) compared to those without PVD (mean PF4 21.8 vs 7.3ng/ml, βTG 98.1 vs 34.2ng/ml). In addition βTG was negatively correlated with postoperative (not preoperative)triglyceride concentrations (r = -0.73, p< 0.05) which were also correlated with PS (r = 0.72, p< 0.05).

Abnormalities in platelet parameters are present in patients with CAD but they do not appear to be sensitive indicators of CAD severity and may well be affected by other factors for example extent of atheroma elsewhere, serum lipids and preoperative stress.