USe of Diagnostic sUbtraction angiography in The isCHemic stroke setting (US DUTCH study)

Introduction There are no recommendations for DSA in the ischemic stroke work-up according to current guidelines. We studied the rate of DSA in ischemic stroke, the recent time-trend (given the recent rapid increase in mechanical thrombectomy), hospital variation and associated factors. Methods This is a retrospective cross-sectional study among Medicare fee-for-service beneficiaries with ischemic stroke admitted between 2016 and 2020 in the United States. ICD-10 codes were used to determine ischemic stroke diagnosis and procedure codes for thrombectomy and DSA. Hospital trends and factors associated with DSA performance were analyzed in hospitals with DSA capacity. Results 7.373 (0.7%) of the 1,085,644 ischemic stroke patients, had a DSA for diagnostic purposes. In the patients that were admitted to a hospital with DSA facility, the following factors showed the strongest association with DSA: younger age (aOR=0.81 [95% confidence interval (CI):0.81-0.83]), thrombectomy rate in that hospital (aOR=2549 [95%CI:610-10663]), transfer (aOR=1.41[95%CI:1.34-1.50]) and carotid disease (aOR=5.8 [95%CI:5.6-6.1]). There was large variation in the hospital DSA rate, varying from 0.07% to 11.1%. Of the variance of DSA rates, 15% was attributed to the residual effect hospital propensity to perform DSA. The top decile of hospitals with the highest DSA rate, performed DSA’s in >2.3% of patients, compared to the 0.6% median. There was no change in DSA rates over time. Conclusion DSA is used infrequently in acute ischemic stroke patients and did not change between 2016 to 2020. Hospital variation in DSA use was however large, and not solely explained by patient and facility factors. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement No funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: NA I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes We used Medicare data that was available for the research group of prof. Burke.