Attainment and maintenance of platelet inhibition through standard dosing of abciximab in diabetic and nondiabetic patients undergoing percutaneous coronary intervention.

BACKGROUND: Although the effectiveness of abciximab (c7E3 Fab; ReoPro) in large populations of patients undergoing a percutaneous coronary intervention has been consistently proved in clinical trials, it is unknown whether all patients achieve and maintain target inhibition during treatment. Diabetic patients in particular are a subgroup of patients with known underlying platelet abnormalities whose long-term response to abciximab has been shown to vary from that of nondiabetic patients. METHODS AND RESULTS: Forty-nine diabetic and 51 nondiabetic patients who received adjunctive abciximab therapy during percutaneous coronary interventions were evaluated prospectively. The degree of platelet function inhibition was determined immediately after the abciximab bolus, 8 hours after the bolus (during the 12-hour abciximab infusion), and the next morning (13 to 26 hours after the bolus) with the use of a rapid platelet function assay (Accumetrics). After the abciximab bolus, platelet function was inhibited by 95+/-4% (mean+/-SD). By 8 hours, the average percent inhibition had decreased to 88+/-9%, with 13% of patients with <80% inhibition. The next morning (mean 19 hours after the bolus), mean inhibition was 71+/-14%. A difference was not found between diabetics and nondiabetics, nor was any physiological parameter found to be predictive of the response to abciximab. CONCLUSIONS: Although the majority of patients achieve and maintain >/= 80% platelet inhibition during the 12-hour infusion with standard-dose abciximab, there is substantial variability among patients. Diabetic status does not appear to influence this variability.

Are we promoting true informed consent in cardiovascular clinical trials?

The purpose of this study was to determine variables contributing to patient participation in randomized clinical trials while assessing the potential relationship of these variables to a valid consent process. Two hundred forty-seven patients were administered a questionnaire after they made their decision about participation. Numerous variables were explored for their relationship to patient participation. Of particular significance were the variables of education, perception of having enough time to decide, and the person approaching the patient. Results of this study reveal the need for further evaluation of informed consent as a process, focusing on the areas of patient autonomy and comprehension.