DIMR Score: A Tool for Determining the Destination of LVO Patients After Thrombolysis

Background Stroke patients with large vessel occlusion (LVO) benefit from thrombolysis (tPA) and mechanical thrombectomy (MT). We aim to characterize triaging patterns in these patients, specifically those who go to perfusion-based imaging first or direct to angio in the drip-and-ship model. Furthermore, we propose that select patients may benefit from CTP prior to MT. Methods A total of 270 patients with acute ischemic stroke secondary to LVO/MeVO were retrospectively evaluated from January 2018 to June 2022. These patients received intravenous tPA from the outside hospital and were transferred for the intention of MT. We compared baseline characteristics between those who received CTP upon arrival and those who went either directly to the angiography suite (DTA) along with logistic regression and functional outcomes. Results Predictors of CTP utilization over DTA was the presence of an M3 occlusion (11.3% vs. 1.7%, p=0.005) and PCA occlusion (12.9% vs. 3.4%, p=0.015). The DTA approach was higher in M1 MCA occlusions (43.2% vs. 27.4%, p=0.038) and basilar occlusions (7.6% vs. 0, p=0.026). DTA patients had a higher NIHSS at the spoke (median NIHSS 15 [9-21] vs. 9 [4.75-14], p<0.001) and the hub (14 [7-20] vs. 7 [3-15.75], p<0.001). There was no significant difference between the DTA and CTP groups in regards to mRS at 90 days (39% vs. 48.4%, p=0.101). Conclusion In the drip-and-ship model, NIHSS and location of an occlusion on initial CTA guide CTP utilization in LVO/ MeVO patients. Long term functional outcomes are not significantly affected by arrival at CTP over DTA. Patients whose transfer is delayed, improve after thrombolysis, present with a MeVO, or are limited by resources at the CSC may benefit from transfer to CT over a DTA approach. We propose this DIMR score may help guide triaging of patients who have an intracranial occlusion and receive thrombolysis. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement No external funding was used to support this manuscript ### 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: University of Toledo IRB Study 108349 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 All data supporting the findings of this study is available upon reasonable request to the primary author * MT : mechanical thrombectomy CTP : computerized tomography perfusion TPA : tissue plasminogen activator/alteplase DTA : direct to angiography CTA : computerized tomography angiography LVO : large vessel occlusion ICU : intensive care unit CSC : comprehensive stroke center MRI : magnetic resonance imaging NIHSS : National Institute of Health Stroke Scale TNK : tenecteplase DTN : door-to-needle TIMI : thrombolysis in myocardial infarction TICI : thrombolysis in cerebral infarction mRS : modified Rankin Scale (MeVO) : medium vessel occlusions DIMR : delayed, improved, MeVO, resource limitation,