The use of embolic signal detection in multicenter trials to evaluate antiplatelet efficacy: signal analysis and quality control mechanisms in the CARESS ( XXXX and @entity117 for Reduction of Emboli in Symptomatic carotid Stenosis) trial.

@entity1 @entity7303 @entity1397 @entity117 @entity543
BACKGROUND AND PURPOSE: The CARESS ( @entity1397 and @entity117 for Reduction of Emboli in Symptomatic carotid Stenosis) trial proved the effectiveness of the combination of @entity1397 and @entity117 compared with @entity117 alone in reducing presence and number of @entity7303 ( @entity7303 ) in @entity1 with recently symptomatic @entity543 . The present study aimed at installing primary and secondary quality control measures in CARESS because @entity7303 evaluation relies on subjective judgment by @entity1 experts. METHODS: As primary quality control, centers participating in CARESS evaluated a reference digital audio tape (DAT) before the study containing both @entity7303 and artifacts. Interobserver agreement of classifying signals as @entity7303 was expressed as proportions of specific agreement of positive ratings (ps+/-values). For all DATs included in CARESS (n=300), online number of @entity7303 and off-line number of @entity7303 read by the central reader were compared using correlation coefficients. As secondary control, a sample of 16 of 300 DATs was cross-validated by another independent reader (post-trial validator). RESULTS: For the reference tape, the cumulative ps+/-value was 0.894 based on 12 of 14 observers. Two observers with very different results improved after a training procedure. Agreement between post-trial validator and central reader was ps+=0.805, indicating very good agreement. Correlation between online evaluation and off-line evaluation of DATs was very good overall (cumulative rho=0.84; P<0.001). CONCLUSIONS: Multicenter studies using @entity7303 as outcome parameter are feasible. However, primary and secondary quality control procedures are important.
