Prehabilitation in patients awaiting elective coronary artery bypass graft surgery - effects on functional capacity and quality of life: a randomized controlled trial.

The trial's stated primary endpoint was change in endothelial function, but this paper reports partial outcomes and does not give that primary result. Many patients were lost: 27 intervention patients withdrew, and 171 of 203 baseline participants completed. The authors state the dropout rate was 25.7%, higher than the 20% assumed for sample size, so the effects need cautious interpretation. The study was single-centre and non-blinded, and neither participants nor investigators were blinded. The prehabilitation was a combined programme, so the separate contribution of cycle ergometer training, light gymnastics, breathing techniques and coordination exercises cannot be separated. The short programme may have been too short to change exercise capacity or the primary endpoint. The control group received no preoperative training or further information, so expectations or attention effects cannot be excluded.

Authors declared no potential conflicts of interest. The methods say the German Heart Research Foundation, Wiliam G. Kerckhoff Foundation and Willy Robert Pitzer Foundation supported the study. The funding section says the authors received no financial support for the research, authorship or publication, but also names Deutsche Herzstiftung, Wiliam G. Kerckhoff-Stiftung and Willy Robert Pitzer Stiftung as funders.

Do not read this as proof that cycle ergometer training alone caused the improvements. The programme also included light gymnastics with breathing and coordination exercises, and all patients later received three-week cardiac rehabilitation, so the contribution of any single component cannot be separated. Do not expect improved cardiopulmonary exercise capacity or better postoperative quality of life: the exercise test showed no significant change, and postoperative quality of life showed no intervention effect.