Challenges to randomized trials in adult and congenital cardiac and thoracic surgery

Methodological Standards for the Design, Implementation, and Analysis of Randomized Trials in Cardiac Surgery: A Scientific Statement From the American Heart Association

Cardiac surgery presents specific methodological challenges in the design, implementation, and analysis of randomized controlled trials. The purposes of this scientific statement are to review key standards in cardiac surgery randomized trial design and implementation, and to provide recommendations for conducting and interpreting cardiac surgery trials. Recommendations include a careful evaluation of the suitability of the research question for a clinical trial, assessment of clinical equipoise, feasibility of enrolling a representative patient cohort, impact of practice variations on the safety and efficacy of the study intervention, likelihood and impact of crossover, and duration of follow-up. Trial interventions and study end points should be predefined, and appropriate strategies must be used to ensure adequate deliverability of the trial interventions. Every effort must be made to ensure a high completeness of follow-up; trial design and analytic techniques must be tailored to the specific research question and trial setting.

Predictors of failure to reach target sample size in surgical randomized trials

It is estimated that 25–30 per cent of RCTs fail to reach their target sample size. Multicentre design, publication year, and commercial sponsor were inversely associated with failure to reach the target sample size. A substantial proportion of surgical trials fail reach target sample size, but the trend is showing improvement.