Cerebral amyloid‐β deposition in patients with diseases of the heart or carotid arteries: A systematic review and meta‐analysis

Abstract Background Cardiovascular disease is increasingly recognized as a contributor to cognitive impairment. Reduced cerebral blood flow alone does not explain this association. Another contributing mechanism could be increased cerebral amyloid‐β accumulation. We hypothesized that patients with diseases of the heart or carotid arteries have more cerebral amyloid‐β accumulation than patients without these diseases. Method We conducted a systematic review to determine whether there is an association between diseases of the heart (heart failure, myocardial infarction, heart valve diseases, arrhythmias and cardiomyopathies) or carotid arteries (stenosis or occlusion of the extracranial internal carotid arteries (ICA)) and cerebral amyloid‐β accumulation, measured with positron emission tomography. We searched Pubmed, EMBASE and Scopus for studies that matched inclusion and exclusion criteria. Where possible, we obtained standardized mean differences (SMD) of amyloid‐β standardized uptake volume ratios (SUVr) with a meta‐analysis using a random‐effects model. Result Seven cross‐sectional studies, two on heart diseases and five on carotid artery diseases, were identified, including a total of 1262 participants (mean age 60‐76 years, 53% female). Six of the seven studies did not find a difference in cerebral amyloid‐β accumulation between patients with or without heart or carotid artery disease. One study including 11 participants found more amyloid‐β in the hemisphere ipsilateral to an ICA stenosis than in the hemisphere of healthy controls. SMD were calculated for atrial fibrillation (AF) (two studies including 746 participants) and unilateral ICA stenosis or occlusion (two studies including 24 participants). Patients with AF tended to have more cerebral amyloid‐β than reference participants (SMD in SUVr 0.14, 95% CI ‐0.06 – 0.34). There was less amyloid‐β in the hemisphere ipsilateral to the ICA stenosis or occlusion compared to the contralateral hemisphere (SMD in SUVr ‐0.13, 95% CI ‐0.70 – 0.43). Although we did not find significant effects. Conclusion Currently available evidence does not support the notion that diseases of the heart or carotid arteries predispose for a higher burden of cerebral amyloid‐β.