Abstract Body (Do not enter title and authors here): Background:
Dementia and coronary artery disease (CAD) frequently coexist in older adults, complicating acute coronary syndrome (ACS) management. The prevalence of dementia among patients undergoing revascularization versus medical management and the distribution of dementia subtypes in this context remain poorly described.

Methods:
In this longitudinal cohort study of adults ≥65 years with ACS hospitalization within an integrated health system from 2010–2020, patients were classified by initial management: percutaneous coronary intervention (PCI), coronary artery bypass artery grafting (CABG), or ACS without revascularization (Norevasc). Baseline dementia and dementia type was identified by ICD-10 codes prior to hospitalization. Descriptive statistics were used to delineate baseline demographics and clinical variables including prior comorbidities. The prevalence of dementia at baseline, as well as the distribution of type of baseline dementia, was compared in the Revascularization vs. Not groups using Chi-Square test.

Results:
26,749 patients were included in this analysis (9,009 PCI or CABG and 17,740 No Revascularization). Patients referred for PCI/CABG were younger (74.9 vs. 77.7; p < 0.001), less likely to be women (34.1% vs. 46.9% p < 0.001) and had fewer comorbidities via Elixhauser Comorbidity Index (4.6 vs. 5.5; p < 0.001). The overall baseline prevalence of dementia was 5.9% with a differential as follows: PCI, 2.0%; CABG, 0.62%; and Norevasc, 7.9% (p < 0.001, Table 1). Among those with baseline dementia, the most common subtype was Alzheimer’s disease (85.7%), followed by vascular dementia (5.7%), Lewy body/Parkinson’s dementia (3.7%), unspecified types (3.6%), and frontotemporal dementia (1.0%). The distribution of dementia subtypes did not differ significantly between patients referred for revascularization vs. not (p = 0.51; Table 2).

Conclusion:
In this large, real-world cohort, baseline dementia was most prevalent among ACS patients managed without revascularization and least common among those undergoing CABG. Alzheimer’s disease was the predominant subtype regardless of management strategy. These findings highlight the importance of routine cognitive assessment in older adults hospitalized with ACS and support further research into tailored care for this higher complexity population.