NAC changes the course of cerebral small vessel disease in SHRSP and reveals new insights for the meaning of stases - a randomized controlled study

Cerebral Microbleeds During Transcatheter Aortic Valve Replacement: A Prospective Magnetic Resonance Imaging Cohort

BACKGROUND

Cerebral microbleeds (CMBs) have been observed in healthy elderly people undergoing systematic brain magnetic resonance imaging. The potential role of acute triggers on the appearance of CMBs remains unknown. We aimed to describe the incidence of new CMBs after transcatheter aortic valve replacement (TAVR) and to identify clinical and procedural factors associated with new CMBs including hemostatic measures and anticoagulation management.

METHODS

We evaluated a prospective cohort of patients with symptomatic aortic stenosis referred for TAVR for CMBs (METHYSTROKE [Identification of Epigenetic Risk Factors for Ischemic Complication During the TAVR Procedure in the Elderly]). Standardized neurologic assessment, brain magnetic resonance imaging, and analysis of hemostatic measures including von Willebrand factor were performed before and after TAVR. Numbers and location of microbleeds on preprocedural magnetic resonance imaging and of new microbleeds on postprocedural magnetic resonance imaging were reported by 2 independent neuroradiologists blinded to clinical data. Measures associated with new microbleeds and postprocedural outcome including neurologic functional outcome at 6 months were also examined.

RESULTS

A total of 84 patients (47% men, 80.9±5.7 years of age) were included. On preprocedural magnetic resonance imaging, 22 patients (26% [95% CI, 17%-37%]) had at least 1 microbleed. After TAVR, new microbleeds were observed in 19 (23% [95% CI, 14%-33%]) patients. The occurrence of new microbleeds was independent of the presence of microbleeds at baseline and of diffusion-weighted imaging hypersignals. In univariable analysis, a previous history of bleeding (P=0.01), a higher total dose of heparin (P=0.02), a prolonged procedure (P=0.03), absence of protamine reversion (P=0.04), higher final activated partial thromboplastin time (P=0.05), lower final von Willebrand factor high-molecular-weight:multimer ratio (P=0.007), and lower final closure time with adenosine-diphosphate (P=0.02) were associated with the occurrence of new postprocedural microbleeds. In multivariable analysis, a prolonged procedure (odds ratio, 1.22 [95% CI, 1.03-1.73] for every 5 minutes of fluoroscopy time; P=0.02) and postprocedural acquired von Willebrand factor defect (odds ratio, 1.42 [95% CI, 1.08-1.89] for every lower 0.1 unit of high-molecular-weight:multimer ratio; P=0.004) were independently associated with the occurrence of new postprocedural microbleeds. New CMBs were not associated with changes in neurologic functional outcome or quality of life at 6 months.

CONCLUSIONS

One out of 4 patients undergoing TAVR has CMBs before the procedure and 1 out of 4 patients develops new CMBs. Procedural or antithrombotic management and persistence of acquired von Willebrand factor defect were associated with the occurrence of new CMBs.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02972008.

Post-stroke treatment with K-134, a phosphodiesterase 3 inhibitor, improves stroke outcomes in the stroke-prone spontaneously hypertensive rat model-A comparative evaluation of antiplatelet drugs

Post-stroke antiplatelet therapy has been proved to reduce the risk of recurrent stroke; however, it may also increase the incidence of intracranial hemorrhage that could offset any benefits. Therefore, the balance between the benefits and risks of antiplatelet drugs is a critical issue to consider. In the present study, we have compared the effects of post-stroke administration of antiplatelet agents on functional outcomes in the stroke-prone spontaneously hypertensive rat (SHRSP), an established animal model that mimics human lacunar stroke and cerebral small vessel disease. We confirmed that a potent phosphodiesterase 3 (PDE3) inhibitor, K-134, significantly improved post-stroke survival rate and survival time, attenuated stroke-induced neurological deficits, and decreased the incidence of cerebral lesion caused by intracerebral hemorrhage and softening. Similarly, cilostazol showed beneficial effects, though to a lower extent with respect to the survival outcome and neurological symptoms. On the other hand, a P2Y12 inhibitor, clopidogrel significantly improved survival outcomes at the higher dose but caused massive bleeding in the brain at both low and high doses. In contrast, no hemorrhagic lesion was observed in K-134-treated SHRSPs despite its antiplatelet activity. Our findings indicate that K-134 may have a superior post-stroke therapeutic outcome in comparison to other antiplatelet drugs.

Small vessel disease and memory loss: what the clinician needs to know to preserve patients' brain health

Small vessel disease (SVD) in the brain manifests in the periventricular and deep white matter and radiographically is described as "leukoaraiosis". It is increasingly recognized as a cause of morbidity from middle age onward and this clinical relevance has paralleled advances in the field of neuroradiology. Overall, SVD is a heterogenous group of vascular disorders that may be asymptomatic, or a harbinger of many conditions that jeopardize brain health. Management and prevention focuses on blood pressure control, lifestyle modification, and symptomatic treatment.

Early microvascular dysfunction in cerebral small vessel disease is not detectable on 3.0 Tesla magnetic resonance imaging: a longitudinal study in spontaneously hypertensive stroke-prone rats

BACKGROUND

Human cerebral small vessel disease (CSVD) has distinct histopathologic and imaging findings in its advanced stages. In spontaneously hypertensive stroke-prone rats (SHRSP), a well-established animal model of CSVD, we recently demonstrated that cerebral microangiopathy is initiated by early microvascular dysfunction leading to the breakdown of the blood-brain barrier and an activated coagulatory state resulting in capillary and arteriolar erythrocyte accumulations (stases). In the present study, we investigated whether initial microvascular dysfunction and other stages of the pathologic CSVD cascade can be detected by serial magnetic resonance imaging (MRI).

FINDINGS

Fourteen SHRSP and three control (Wistar) rats (aged 26-44 weeks) were investigated biweekly by 3.0 Tesla (3 T) MRI. After perfusion, brains were stained with hematoxylin-eosin and histology was correlated with MRI data. Three SHRSP developed terminal CSVD stages including cortical, hippocampal, and striatal infarcts and macrohemorrhages, which could be detected consistently by MRI. Corresponding histology showed small vessel thromboses and increased numbers of small perivascular bleeds in the infarcted areas. However, 3 T MRI failed to visualize intravascular erythrocyte accumulations, even in those brain regions with the highest densities of affected vessels and the largest vessels affected by stases, as well as failing to detect small perivascular bleeds.

CONCLUSION

Serial MRI at a field strength of 3 T failed to detect the initial microvascular dysfunction and subsequent small perivascular bleeds in SHRSP; only terminal stages of cerebral microangiopathy were reliably detected. Further investigations at higher magnetic field strengths (7 T) using blood- and flow-sensitive sequences are currently underway.