Whole blood impedance platelet aggregometry and ischemic heart disease. The Caerphilly Collaborative Heart Disease Study.

Abstract

The Caerphilly Collaborative Heart Disease Study is based on a large cohort of men who were ages 49 to 64 years at the time of the study. We report the results for platelet aggregation measured in whole blood from a subsample of 308 men. The index of sensitivity used was the minimum concentration of adenosine diphosphate that produced a defined degree of impedance change in the Chronolog 560 aggregometer. There was a marked association between aggregation and prevalent ischemic heart disease (IHD). The odds ratios and 95% confidence intervals (Cl) for prevalent IHD in men with the most sensitive platelets compared with those with the least sensitive platelets were 3.6 (95% Cl: 1.1 to 12.2) for angina; 7.3 (95% Cl: 2.0 to 24.3) for previous myocardial infarction (Ml); and 2.7 (95% Cl: 1.0 to 7.6) for electrocardiogram evidence of ischemia. The confidence limits for these odds ratios are large because of the small sample size, but the estimates of odds ratio are relatively large compared to similar relationships between the traditional risk factors of serum cholesterol, blood pressure, smoking, and prevalent IHD (1.5 to 2.5). A number of factors that might confound the relationships between platelets and IHD were examined, but the associations remained statistically significant when these were taken into account. (Arteriosclerosis 10:1032-1036, November/December 1990) E vidence is accumulating that platelets play a key role in ischemic heart disease (IHD). Case-control studies demonstrate positive relationships between increased platelet aggregation and IHD 12 but of course suffer from the inferential dilemma of whether differences in platelet aggregation preceded the IHD event or were caused by it.Platelet aggregability is usually assessed by turbidimetric methods with the use of platelet-rich plasma (PRP) prepared by centrifugation and diluted to a standard platelet concentration. These preparatory procedures are likely to modify the subsequent behavior of the platelets, and in addition to this, red blood cells and other components of whole blood that may affect platelet behavior are removed and are not involved in the test. A more realistic procedure for public health screening would seem to be the testing of platelets in whole blood. In this article, we report the association between aggregation measured in whole blood by an impedance method and IHD in a population sample of older men. MethodsIn the Caerphilly Heart Disease Study, 3 a major emphasis is put on tests of hemostasis, including the measurement of platelet aggregation to adenosine diphosFrom the MRC Epidemiology Unit, Cardiff, South Wales, UK, and INSERM, Unite 63, Bron, France.Stephen Rogers is now at the Institute of Medical Research, Tari, Papua New Guinea.Address for correspondence: Dr. P.C. Elwood, MRC Epidemiology Unit, 4 Richmond Road, Cardiff CF2 3AS, South Wales, UK.Received January 18, 1990; revision accepted May 1, 1990. phate (ADP) in PRP. Toward the end of the second phase of examinations of the men in this cohort, resources became a...

Platelets as Predictors of Vascular Risk: Is There a Practical Index of Platelet Activity?

“…The Caerphilly Collaborative Heart Study recruited a general population of 2,398 men aged between 49 and 66 years in 1979 to 1982 (78)(79)(80)(81)(82). The risk of CHD and the association with platelet aggregation measurements was assessed.…”

“…However, aggregometry procedures in PRP may provide a cheaper and quicker tool to estimate cardiovascular risk, while impedance changes in whole blood are slower, have poor reproducibility, and their cost is higher because of the use of the platinum electrodes that may need replacement. 11,16,19,27,28,48,50,58,[78][79][80][81][82]131,132 Aggregometry procedures in subpopulations of the Caerphilly prospective study performed in PRP and whole blood failed to prove that increased platelet hyperactivity is significantly related to an increased risk of subsequent CHD (78)(79)(80)(81)(82). However, there is evidence of such a link from some other studies (83).…”

Platelets and Vascular Risk: An Option for Treatment

“…No relations were reported with angina. Platelet aggregation carried out in WB in a sub sample of 308 men, showed that there was a marked association with prevalent CHD [70]. Significant relations were shown between past MI and electrocardiographic evidence of ischaemia and ADP-induced aggregation and between electrocardiographic evidence of thrombin-induced aggregation [71].…”

“…The Caerphilly Collaborative Heart Disease Study was carried out in a large cohort of men (2,398) aged 49-66 years [69][70][71][72][73][74]. Agonist-induced platelet aggregation was assessed in fasting blood samples in relation to prevalent angina, past MI and electrocardiographic evidence of CHD.…”

Clinical Utility of Available Methods for Determining Platelet Function

“…The Caerphilly Collaborative Heart Study measured platelet aggregation and noted it to be a significant risk factor for ischemic heart disease even after controlling for other risk factors [12]. The HAPARG study showed that spontaneous platelet aggregation was a risk factor for vascular occlusive events [13].…”