This was a multicenter international retrospective observational study (63 sites from 16 countries; Figure S1) that included patients presenting to an acute care hospital and diagnosed with CAD without concomitant major trauma. We identified adult patients aged ≥18 years with CAD based on International Classification of Diseases, Ninth Revision codes (443.21 and 443.24),8,9 International Classification of Diseases, Tenth Revision codes (I77.71, I77.74, and I77.75),10 or from institutional registries. These codes have been used or validated in prior studies.8–10
The patients’ vascular neuroimaging studies were reviewed by site principal investigators, and only those with clinical suspicion for CAD and imaging confirmation were included. Imaging confirmation required the presence of at least one of the following imaging features: crescent-shaped hyperintensity in the vessel wall indicating an intramural hematoma; a double lumen sign; the presence of a dissecting pseudoaneurysm, intimal flap, or vessel irregularity; or flame-shaped or tapering stenosis or occlusion of the artery at a typical dissection site and without evidence of atherosclerotic changes. Imaging reports, when available, were reviewed by neurologists at the lead site to confirm a dissection diagnosis.
We excluded patients with incidental chronic dissection, those with major head or neck trauma within the previous 4 weeks (eg, causing skull or cervical fractures or hemorrhage), those with a dissecting aneurysm causing primary subarachnoid hemorrhage, and those with iatrogenic dissection.








