"There is nothing better than participating in this study": Living the PAPAartis cardiovascular randomised controlled trial.

Qualitative research can bring new dimensions of understanding decision-making process in clinical trials. Participating in a randomized clinical trial requires patients to accept complex information and make decisions in a context of uncertainty. It becomes especially complicated in the case of serious diseases in which the treatment itself implies unknown risks. This study examines these issues in the context of the PAPAartis randomized clinical trial, which aims to prevent spinal cord injuries that can occur as an adverse event following complex surgical repair of thoracoabdominal aneurysm. In this study, we accessed a group of 16 patients participating in the trial and, through in-depth interviews, sought to understand the decision-making process when taking part in the trial and their experience of it. Our results showed that patients participated for different reasons: due to trust in doctors, the hope of having a better treatment or for altruistic and collaborative reasons with science. Many patients felt they did not fully understand the extraneous information provided about the study and the complex nature of the procedure. Avoidance of paraplegia played a fundamental role in the decision to participate in this trial. Family support and the socioeconomic conditions of the patients influenced the recovery process after surgery.