Antiplatelet Therapy, AF and Coronary Stenting
Sample size was calculated after examination of the rate of events in our previous prospective study consisting of the systematic analysis of case records. According to these data, we foresee that 92.1% of patients assigned to TT will be free of cardiovascular events, whereas this percentage will be higher, approximately 96%, with DAPT, and a 3% difference will be considered clinically significant. Sample size was increased by 5% to account for potential dropouts. According to these data, 152 patients per group will suffice, with a power of 80% and a P ≤ .05 considered as significant to declare DAPT as not inferior to TT. The final sample size is estimated at 304 patients, of whom 50% will receive DAPT and 50% TT (152 patients per treatment arm). The study was designed as a noninferiority trial. Analysis will be performed via 2 approaches: intention to treat and per protocol. A confirmatory analysis will be made of the demographic balance in the treatment groups. Descriptive statistics (mean, SD, median, and interquartile range for continuous data, and frequency tables for categorical data) of the main variables will be performed categorical demographic variables will be compared using the χ test. Continuous demographic variables including total body surface will be compared using the Student t tests. Primary and secondary end point analyses will be based on time to first event. Kaplan-Meier–based cumulative incidence rates will be calculated and compared by means of the log-rank test. Multivariate analyses will be made for these purpose end points: primary and secondary, MACE, major adverse events, and for the following single outcomes: stroke, myocardial infarct, major bleeding, and death.
Although patients will be included in the study based on the CHADS2 score, the CHADS2-VASC and HAS-BLED scores will also be calculated in all patients to permit which will allow performing post hoc analyses once the study has been completed.
Statistical Analysis
Sample size was calculated after examination of the rate of events in our previous prospective study consisting of the systematic analysis of case records. According to these data, we foresee that 92.1% of patients assigned to TT will be free of cardiovascular events, whereas this percentage will be higher, approximately 96%, with DAPT, and a 3% difference will be considered clinically significant. Sample size was increased by 5% to account for potential dropouts. According to these data, 152 patients per group will suffice, with a power of 80% and a P ≤ .05 considered as significant to declare DAPT as not inferior to TT. The final sample size is estimated at 304 patients, of whom 50% will receive DAPT and 50% TT (152 patients per treatment arm). The study was designed as a noninferiority trial. Analysis will be performed via 2 approaches: intention to treat and per protocol. A confirmatory analysis will be made of the demographic balance in the treatment groups. Descriptive statistics (mean, SD, median, and interquartile range for continuous data, and frequency tables for categorical data) of the main variables will be performed categorical demographic variables will be compared using the χ test. Continuous demographic variables including total body surface will be compared using the Student t tests. Primary and secondary end point analyses will be based on time to first event. Kaplan-Meier–based cumulative incidence rates will be calculated and compared by means of the log-rank test. Multivariate analyses will be made for these purpose end points: primary and secondary, MACE, major adverse events, and for the following single outcomes: stroke, myocardial infarct, major bleeding, and death.
Although patients will be included in the study based on the CHADS2 score, the CHADS2-VASC and HAS-BLED scores will also be calculated in all patients to permit which will allow performing post hoc analyses once the study has been completed.