Detection of atrial fibrillation by implantable loop recorders following cryptogenic stroke: A retrospective study of predictive factors and outcomes.

PURPOSE: Cryptogenic strokes account for 40% of ischemic strokes. Atrial fibrillation (AF) is a known cause of stroke. Current data shows that occult AF is detected by implantable devices at higher rates than conventional monitoring. The objective of this study was to investigate risk factors and outcomes associated with AF detection by implantable loop recorders (ILRs) in patients with cryptogenic stroke. METHODS: We conducted a retrospective study of 172 patients admitted with cryptogenic stroke at Ascension St John and Macomb-Oakland Hospitals who had ILRs placed from 1/1/2016 to 1/31/2020. AF detection was defined as sustained AF for 30 s. RESULTS: The incidence of AF detection by ILR was 14% (24/172) over a mean follow-up of 12.75 ± 10.71 months. The mean duration of monitoring prior to AF detection was 4.5 months. The median duration of AF was 6 min. With univariable analysis, older age (p = 0.03), male sex (p = 0.09), embolic stroke pattern on imaging (p = 0.06), and presence of symptoms (p = 0.001) were associated with AF detection. Using multivariable analysis, patients with AF were more likely to be older (OR = 1.04, p = 0.04), male (OR = 3.6, p = 0.03), symptomatic (OR = 6.3, p = 0.01), and had embolic stroke pattern (OR = 3.3, p = 0.04). 95.8% of patients with AF were started on anticoagulation for secondary stroke prevention. CONCLUSION: In patients with cryptogenic stroke, age, sex, stroke pattern, and presence of AF symptoms are independent predictors of AF detection by ILR. Most patients with AF were started on anticoagulation for secondary stroke prevention.

Sex-Specific Differences in an ApoE(-/-):Ins2(+/Akita) Mouse Model of Accelerated Atherosclerosis.

Diabetic patients have a twofold to fourfold increased risk of cardiovascular disease. Despite a vast amount of research, the underlying mechanisms that predispose individuals with diabetes to the development of cardiovascular disease are unclear. To further our understanding of how diabetes promotes atherosclerosis, we have established, characterized, and manipulated a new model of hyperglycemia-induced atherosclerosis: the apolipoprotein E-deficient (ApoE(-/-)):Ins2(+/Akita) mouse. All mice were fed a standard chow diet. Male ApoE(-/-):Ins2(+/Akita) mice developed chronic hyperglycemia, which significantly accelerated atherosclerosis. Female ApoE(-/-):Ins2(+/Akita) mice presented hyperglycemia that normalized by 15 weeks of age. Despite the transient hyperglycemia, advanced atherosclerosis was observed at 15 weeks of age compared with ApoE(-/-) females. To better understand these differences, subsets of mice were castrated or ovariectomized at 5 weeks of age. Castrated ApoE(-/-):Ins2(+/Akita) mice showed a reduction in blood glucose levels that correlated with the amelioration of atherosclerosis. Interestingly, castrated normoglycemic ApoE(-/-) mice developed larger atherosclerotic lesions than sham-operated on controls. Ovariectomized ApoE(-/-):Ins2(+/Akita) mice presented chronic hyperglycemia, and atherosclerosis appeared to be advanced. We have characterized the distinctive sex-specific phenotypes exhibited by the ApoE(-/-):Ins2(+/Akita) mouse model and present evidence for the action of sex hormones on pancreatic ß-cell function and the vasculature that affect the regulation of blood glucose levels and the development of atherosclerosis. This model will provide a test bed to further delineate these effects.

Dysglycemia and the Density of the Coronary Vasa Vasorum.

OBJECTIVE: This study was conducted to determine the relationship between dysglycemia and the coronary artery vasa vasorum density. RESEARCH DESIGN AND METHODS: The left anterior descending coronary artery was removed from 57 deceased individuals during autopsy, and the capillaries in the vessel wall were identified using fluorescent immunohistochemical staining. HbA1c was determined in postmortem whole blood for each individual. The density of the vasa vasorum in the intima-media and the adventitia was manually quantified and recorded by readers unaware of the individual's other characteristics. RESULTS: The individuals with diabetes had a lower density of the coronary vasa vasorum than those without diabetes. The higher the HbA1c, the lower the density of these vessels in the adventitia and entire vessel wall. CONCLUSIONS: Dysglycemia-induced damage to the vasa vasorum may promote ischemic heart disease in people with diabetes.