Association between the on-site availability of treatment options of endarterectomy or stenting and the outcomes after carotid revascularisation

<b></b> <i>Background:</i> The aim of this study was to determine whether the on-site availability of treatment options (carotid endarterectomy CEA, carotid artery stenting CAS) was associated with patient and hospital characteristics, medical management and outcome. <i>Materials and methods:</i> This study is a pre-planned sub study of the Integration and Spatial Analysis of Regional, Site-specific, and patient-level factors for Improving Quality of treatment for carotid artery stenosis (ISAR-IQ) project, which analysed data from the nationwide German statutory quality assurance carotid database. Hospitals were categorized according to on-site availability of: CEA-only, CAS-only, and both CEA and CAS centre. Primary outcome event was any in-hospital perioperative stroke or death. The multivariable regression analysis was adjusted for age, sex, American Society of Anesthesiologists Physical Status (ASA stage), symptomatic status, antiplatelet therapy, ipsilateral and contralateral degree of stenosis, pre- and post-procedural assessment by a specialist in neurology, and hospital volume. <i>Results:</i> A total of 201,330 patients undergoing CAS or CEA for asymptomatic or symptomatic carotid stenosis between 2012 and 2018 were included. 74% were treated in hospitals that offer both methods, 24% in CEA-only centres and 2.5% in CAS-only centres. The median annual number of cases for CEA and CAS was 44 and 7, respectively, in centres that offered both compared to 16 and 6 in centres that performed either CEA or CAS, respectively. The overall stroke and death rate until hospital discharge was 2.1%. In centres providing both CEA and CAS, the stroke and death rates were 2.0% for CEA and 2.4% for CAS. These figures were 2.0% in centres providing CEA-only and 3.0% for CAS-only centres. The multivariable regression analysis showed significant higher perioperative stroke or death rate in the CEA-only group (adjusted Odds Ratio aOR=1.12, 95%-confidence interval (CI) 1.03-1.21) and CAS-only group (aOR=1.26, 95%-CI 1.04-1.52) versus the combined CEA and CAS group. <i>Conclusions:</i> Centres providing both CEA and CAS had a lower risk of perioperative stroke and death than centres performing CEA-only or CAS-only. The minimum volume recommendations of the national guideline were not achieved in the median by CEA-only and CAS-only centres. This could be a starting point for public health measures to increase guideline conformity and treatment quality.