Abstract Body: Background: Certain findings on transthoracic echocardiography (TTE) are associated with a recognized cardioembolic stroke mechanism but less is known about the prevalence of those findings in other subtypes, especially cryptogenic stroke patients. We sought to describe the prevalence of these abnormalities reported on TTE in stroke patients in a large, population-based stroke study and compare the findings specifically of cryptogenic stroke patients to those with the other identified subtypes.

Methods: In 2015, the Greater Cincinnati/Northern Kentucky Stroke Study identified all stroke cases in the 5-county area surrounding Cincinnati by ICD 9/10 codes. Potential cases were abstracted by trained study nurses and physician adjudicated, which included assigning ischemic stroke etiology based on our epidemiologic criteria. TTE reports were reviewed. Demographic information, medical history, stroke subtype and prespecified TTE features were collected for each patient and compared across stroke subtype groups. We performed a pair-wise post hoc comparison to the cryptogenic group if a difference was found amongst the groups based on the omnibus test.

Results: In 2015, there were 2481 ischemic strokes among patients 18 years or older in our 5-county area. Of these, 677 (27%) were cardioembolic, 312 (13%) large artery atherosclerotic (LAA), 419 (17%) small vessel, 154 (6%) other etiology and 919 (37%) cryptogenic. Of these ischemic stroke events, there were 1503 (61%) with TTE reports available. The severity for diastolic dysfunction, left atrial (LA) dilation, left ventricular hypertrophy and valvular abnormalities were not included in the data analysis. Cardioembolic strokes had significantly higher proportions of LA dilation, mitral and aortic regurgitation, greater LA size and area, and lower left ventricular ejection fraction (LVEF) compared to cryptogenic patients. LAA patients had a higher LA size and lower LVEF compared to cryptogenic patients. The only difference found between cryptogenic and small vessel patients was higher LA size in the latter group.

Conclusion: In a large population-based study, TTE findings in cryptogenic stroke patients were less similar to cardioembolic stroke and more similar to other subtypes. While our findings suggest it is less likely to have echocardiographic findings concerning for cardioembolic stroke in the cryptogenic population, further studies on novel and comprehensive cardiac markers are needed to confirm this.