3.1 Patient/control subject characteristics
In general, this was a middle-aged group of individuals, as summarized in the Table: Patients and control subjects were of similar ages, with a small majority of females. Patients were more likely than control subjects to have histories of hypertension and hyperlipidemia. Patients were typically evaluated during treatment with L-channel calcium antagonists for prophylaxis of angina pectoris. Demographics (data not shown) did not vary significantly according to the type of CAS (PA versus CSFP).
3.2 Platelet reactivity during quiescent (“chronic”) phase: CAS patients exhibit hyper-reactivity and impaired responses to SNP
Stable CAS patients exhibited significantly greater aggregability to ADP than control subjects: - mean responses were 8.7 ± 0.3 vs 6.5 ± 0.3 ohms (p < 0.0001). Conversely, there was substantial hypo-responsiveness to SNP. Mean inhibition of ADP-induced platelet aggregation by SNP was 15.7 ± 1.8 vs. 32.6 ± 3.9% in patients and control subjects respectively (p < 0.0001; Fig. 1 ).
However, both pro-aggregatory and anti-aggregatory effects did not vary significantly according to the type of CAS diagnosed at coronary angiography. Responses to ADP were 8.9 ± 0.3 and 8.3 ± 0.5 ohms for PA versus CSFP respectively (p = NS), and anti-aggregatory effects of SNP, compared in Fig.1 , were virtually identical.