Validation of the Clinical Frailty Scale in vascular surgery: a protocol

Introduction: Frailty is a complex, dynamic and multifactorial syndrome. It is common in patients with vascular disease due to increased age and comorbidities. Identifying those with frailty preoperatively can help inform decisions about major interventional treatments and tailor postoperative care. This study aims to validate the Rockwood Clinical Frailty Scale (CFS) in patients undergoing major vascular surgery and determine whether the CFS can predict postoperative outcomes. Methods: Validation study of the CFS as a measure of frailty in patients undergoing major vascular surgery in a single-centre retrospective cohort study. Consecutive patients undergoing major vascular surgery at one tertiary vascular centre between 3 August 2022 and 31 December 2023 will be included. The electronic Frailty Index will be used as the reference standard, against which the CFS will be assessed. Diagnostic accuracy will be compared in each of the following patient groups: major lower limb amputation, aortic aneurysm repair, lower limb revascularisation and carotid endarterectomy. Prognostication will explore the ability of CFS to predict mortality, complications, length of stay and discharge destination. A sample size of 97 patients per subgroup will be required for an estimated sensitivity of 90% and specificity of 85%, based on local prevalence of documented frailty scores. Conclusion: This study aims to validate the CFS in vascular patients and assess the ability of the CFS to predict postoperative outcomes. This will help to inform shared decision making and postoperative care.