“ Cerebrovascular stressing”: dipyridamole-induced S100B elevation predicts ischemic cerebrovascular events

The role of atrial fibrillation in vascular cognitive impairment and dementia: epidemiology, pathophysiology, and preventive strategies

The aging population in Europe faces a substantial burden from dementia, with vascular cognitive impairment and dementia (VCID) being a preventable cause. Atrial fibrillation (AF), a common cardiac arrhythmia, increases the risk of VCID through mechanisms such as thromboembolism, cerebral hypoperfusion, and inflammation. This review explores the epidemiology, pathophysiology, and preventive strategies for AF-related VCID. Epidemiological data indicate that AF prevalence rises with age, affecting up to 12% of individuals over 80. Neuroimaging studies reveal chronic brain changes in AF patients, including strokes, lacunar strokes, white matter hyperintensities (WMHs), and cerebral microbleeds (CMHs), while cognitive assessments show impairments in memory, executive function, and attention. The COVID-19 pandemic has exacerbated the underdiagnosis of AF, leading to an increase in undiagnosed strokes and cognitive impairment. Many elderly individuals did not seek medical care due to fear of exposure, resulting in delayed diagnoses. Additionally, reduced family supervision during the pandemic contributed to missed opportunities for early detection of AF and related complications. Emerging evidence suggests that long COVID may also elevate the risk of AF, further complicating the management of this condition. This review underscores the importance of early detection and comprehensive management of AF to mitigate cognitive decline. Preventive measures, including public awareness campaigns, patient education, and the use of smart devices for early detection, are crucial. Anticoagulation therapy, rate and rhythm control, and addressing comorbid conditions are essential therapeutic strategies. Recognizing and addressing the cardiovascular and cognitive impacts of AF, especially in the context of the COVID-19 pandemic, is essential for advancing public health.

Detection of silent cerebral microcirculatory abnormalities in patients with manifest ischemic coronary disease: a perfusion brain MRI study combined with dipyridamole stress

OBJECTIVES

Intravenous dipyridamole (DP) can induce transient perfusion abnormalities in the heart but also the brain indicated by brain SPECT. L-arginine can regulate the vascular tone via nitric oxide (NO). Therefore, we examined cerebral blood volume (CBV) by perfusion MRI and L-arginine level before and after DP stress in patients, who developed transient neurological signs, and compared these to unaffected patients.

DESIGN

A total of nine patients with ischemic coronary disease after myocardial perfusion scintigraphy were selected for this prospective pilot study. Four had DP-induced transient mild neurologic signs during myocardial perfusion scintigraphy, while five had no neurological signs. By using perfusion MRI in both groups in a second stage, we examined CBV in identical areas of the two hemispheres before and during DP stress. Besides, pre-and post-stress L-arginine serum levels were also analyzed by high-performance liquid chromatography. Trial registration: NCT03688815.

RESULTS

CBV in the sensory-motor area at baseline was significantly higher in patients with DP-induced transient neurological signs compared to patients without signs (p = 0.028). Intravenous DP normalized the higher perfusion by decreasing CBV, and also increased serum L-arginine level (p = 0.001).

CONCLUSIONS

Intravenous DP changed the CBV accompanied by a systemic elevation of L-arginine: this indicates a direct vasorelaxing effect on brain vessels, and an indirect vasodilator effect through L-arginine release presumably via NO. In areas with decreased CBV before DP, such double effects caused transient neurological symptoms presumably due to steal phenomenon. Therefore, intravenous DP may have a potential to identify patients with high risk for cerebral ischemia.