The CREST-2 experience with the evolving challenges of COVID-19: A clinical trial in a pandemic.

The coronavirus disease 2019 pandemic has disrupted the lives of whole communities and nations. The multinational multicenter National Institute of Neurological Disorders and Stroke Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial stroke prevention trial rapidly experienced the effects of the pandemic and had to temporarily suspend new enrollments and shift patient follow-up activities from in-person clinic visits to telephone contacts. There is an ethical obligation to the patients to protect their health while taking every feasible step to ensure that the goals of the trial are successfully met. Here, we describe the effects of the pandemic on the trial and steps that are being taken to mitigate the effects of the pandemic so that trial objectives can be met.