Design considerations and feasibility for a clinical trial to examine coronary screening before kidney transplantation (COST)

Background: It is unclear whether benefits outweigh harms for routine screening and prophylactic revascularization to prevent coronary artery disease (CAD) in asymptomatic kidney transplant candidates. Study Design: Pilot feasibility study with prospective observational data collection and patient interviews. Setting & Participants: Consecutive patients referred for kidney and/or pancreas transplant at 26 major transplant centers in the United States. Predictors: Older age, diabetes, prior cardiovascular disease, and multiple traditional CAD risk factors. Outcomes: Eligibility and willingness to participate in a randomized controlled trial (RCT) to study the effect of CAD screening on major adverse cardiac events. Measurements: Patients who would be candidates for a hypothetical RCT of CAD screening were interviewed and asked if they would participate in such a trial. Sample size for the trial was estimated using data for Medicare patients in the US Renal Data System with major adverse cardiac events as the primary end point. Results: Of consecutive eligible patients, CAD evaluation was not indicated in 398 (24%), already completed before referral in 602 (36%), and pending (and hence eligible for an RCT) in 665 (40%). Of 241 interviewed, 73% indicated they would be willing to participate in an RCT. We estimated that ∼4,000 would need to be enrolled to detect a 20% decrease in major adverse cardiac events at >80% power at P < 0.05. Limitations: Willingness to participate in an actual clinical trial may be different from indicated in an interview. Conclusion: An RCT to compare the effects of routine screening for CAD versus no screening on major adverse cardiac events is feasible.