Detailed statistical analysis plan for the neurological complications in endoscopic versus open radial artery harvest (NEO) randomised clinical trial

INTRODUCTION: Coronary artery bypass grafting can be conducted using the radial artery as a bypass graft. However, it remains unclear which harvesting method is superior, i.e. endoscopic or open radial artery, and which site for proximal anastomosis of the radial artery has the greatest benefits? METHODS: The NEO Trial is a single site randomised clinical trial with a 2 × 2 factorial design. The first comparison assesses endoscopic versus open radial artery harvest with a primary outcome of hand function and secondary outcomes of neurological deficits through clinical exams and neurophysiological studies. The primary outcome is postoperatively hand function at three months. We anticipate a mean difference of 3 points with a standard deviation of 8 points, a power of 90%, and a type I error of 5%, resulting in a required sample size of 300 participants randomised 1:1. Secondary outcomes are neurological deficits (based on nerve conduction measurements, algometry test and von Frey hair test), clinical neurological examination of cutaneous sensibility, and registration of complications in the donor arm (haematoma formation, wound dehiscence, and/or infection). The second comparison assesses two different proximal anastomotic sites, i.e. aorto-radial anastomosis versus mammario-radial anastomosis. The primary outcome is a composite of cerebrovascular events and the secondary outcome is graft patency evaluation by multi-slice computer tomography-scan. These outcomes will be assessed at 1 year postoperatively, and the results of this comparison will be exploratory only. Both comparisons will be analysed using intention-to-treat and intervention groups will be compared using linear regression, logistic regression, or Mann–Whitney U test depending on data type. Two independent statisticians will follow the present plan and conduct the analyses which will hereafter be fused into a final analysis based on consensus. CONCLUSION: This detailed analysis plan will increase the validity of the NEO trial results by predefining the statistical analysis in detail. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01848886. Registered 25 February 2013. Danish Ethics committee number: H-3–2012-116. Danish Data Protection Agency: 2007–58-0015/jr. n:30–0838. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-022-06869-7.