Rapid access to care after an acute stroke is one of the most important aspects to improve the outcomes of this devastating disease. Primary and comprehensive stroke centers have a shared objective, to give IV-TPA as soon as possible if the situation warrants it. Comprehensive stroke centers are usually involved in carrying on clinical trials and have access to a multidisciplinary team that includes neurointensivist, neurosurgeons, and neuroradiologist, among others. We usually think of cases from a comprehensive stroke center, usually, tertiary care centers, to have a referral bias due to the complexity of their disease.
Atrial Fibrillation is Associated With Reduced Brain Volume and Cognitive Function Independent of Cerebral Infarcts
Stefansdottir H, Arnar DO, Aspelund T, Sigurdsson S, Jonsdottir MK, Hjaltason H,et al. Atrial Fibrillation is Associated With Reduced Brain Volume and Cognitive Function Independent of Cerebral Infarcts. Stroke. 2013
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small-vessel disease caused by mutations in the NOTCH3 gene. Ragno and colleagues report 5 CADASIL patients with R1006C mutation in the exon 19 of the NOTCH3 gene who develop parkinsonism during the late stage of the disease.
These patients are characterized by slow onset of parkinsonism symptoms after the diagnosis of CADASIL with early shuffling of gait, akathesia, rigidity, and postural instability but with rare presence of tremor. Symptoms are bilateral and non responsive to treatment with levodopa unlike idiopathic Parkinson’s Disease. MRI shows increased signal in periventricular white matter, internal and external capsules, basal ganglia and thalamus.
Parkinsonism was seen in only 5 (11%) of the total 45 CADASIL patients with R1006C mutation followed by the authors. Based on previous literature basal ganglia symptoms were present in 48% of patients older than 60 years. Parkinsonism is probably a late feature of many CADASIL patients irrespective of type of mutation in the NOTCH3 gene because of the involvement of basal ganglia and its connections. The significance of different types of NOTCH3 mutation in these patients causing phenotypic variability in the presentation of parkinsonism symptoms remains to be determined.
Strictly Lobar Microbleeds Are Associated With Executive Impairment in Patients With Ischemic Stroke or Transient Ischemic Attack
Cerebral microbleeds (CMBs) are small perivascular hemorrhages seen on MR susceptibility sequences. They are markers of microangiopathic disease mainly classified into two general patterns: deep CMBs signifying hypertensive arteriopathy; and strictly lobar CMBs signifying Cerebral Amyloid Angiopathy (CAA). CMBs are increasingly recognized as a hallmark of small vessel pathology. The rationale for studying CMBs and its correlation to cognitive dysfunction stems from the putative relationships between cerebral small vessel disease, vascular cognitive impairment (VCI), and Alzheimer’s disease (AD). Studies have shown the synergistic effect of cerebrovascular disease and neurodegenerative pathology in producing more severe cognitive dysfunction.
Although the association between CMB and cognitive function has been explored in the past with large population studies, the nature of this link in the stroke population is obscure. As such, in a study by Werring et al, the authors investigated this relationship in a cohort of patients with known ischemic strokes or TIA who had undergone MRI (including GRE T2*-weighted and FLAIR sequences), and complete neuropsychological testing in multiple cognitive domains. The study also looked at what location of CMB is most associated with cognitive dysfunction. Of the 320 patients included, at least one CMB was identified in 72 patients (22.5%). Thirty patients (42%) had strictly lobar CMBs. Impairment in executive functions, but not other cognitive domains, was more prevalent in patients with CMBs regardless of the location. Moreover, the presence and number of strictly lobar CMBs (≥1 or ≥5) was independently associated with increased likelihood executive impairment.
The results of this study bring several points to mind. First, whether there is a direct cause and effect between CMBs and cognitive impairment remains unclear. Second, this study gives added evidence that strictly lobar CMBs may reflect cognitive impairment associated with CAA. Finally, while Gradient-echo is widely used as a standard sequence for detecting hemosiderin on MRI, newer MRI techniques such as T2*-weighted angiography (SWAN) and Susceptibility-weighted imaging (SWI) will be even more sensitive at uncovering the presence of CMBs. As the authors suggested, ascertaining the exact nature of the co-existence and interaction between neurodegenerative and cerebrovascular processes may have important implications for the treatment and prevention of cognitive impairment in stroke patients.
Ayerbe L, Ayis S, Crichton S, WolfeCDA, Rudd AG. The Natural History of Depression up to 15 Years After Stroke: The South London Stroke Register. Stroke. 2013.
In a study recently published online in Stroke, Ayerbe and colleagues are studying the incidence, prevalence, duration, and recurrence rate of depression up to 15 years after stroke. Evidence on the natural history and prognosis of depression after stroke is still lacking which complicate treatment strategies. Interventions for depression after stroke has limited effect because it is not started at the right time or not given for an adequate length of time to obtain maximal sustained response.
This is a prospective population-based cohort of 1233 patients, in the South London Stroke Register between 1995 and 2009, showed that the incidence of depression post-stroke was 7-21% in the 15 years following stroke. Thirty three percent of post-stroke depression started in the first three month, half of them recovered after one year. Interestingly, proportion of recurrence ranged from 38% in year two to 100% in year 14.
Post-stroke depression requires periodic clinical attention in the long term. This study shed light on the high rate of recurrence of depression post-stroke. Assuming that a patient recovering from depression is a “closed case” could lead to a late diagnosis or an overlooking of a further episode.
Zhu G, Michel P, Aghaebrahim A, Patrie JT, Xin W, Eskandari A, et al. Computed Tomography Workup of Patients Suspected of Acute Ischemic Stroke: Perfusion Computed Tomography Adds Value Compared With Clinical Evaluation, Noncontrast Computed Tomography, and Computed Tomography Angiogram in Terms of Predicting Outcome. Stroke. 2013
Determining a balance between blood pressure that is neither too high leading to hematoma expansion, nor too low leading to hypoperfusion has always been a challenge in patients with acute intracranial hemorrhage. Butcher et al. randomized 75 spontaneous ICH patients within 24 hours to two groups, one with goal SBP<150 and the other with goal SBP<180. They obtained CT perfusion images to assess perihematoma relative CBF, which was defined as the difference between perihematoma and contralateral homologous region CBF. The result was that perihematoma relative CBF was not different in both groups, leading to the conclusion that acute BP reduction does not lead to cerebral ischemia.
This study reproduced the safety of acute BP lowering shown in the INTERACT trial. A recent study has shown the development of ischemic DWI lesions on MRI in bilateral hemispheres associated with BP reduction in ICH patients. This raises the question that relative CBF may not the best parameter to determine risk of ischemia, and this may be better demonstrated in a prospective study utilizing MRI. The authors address this concern by pointing out that there was no significant difference found in relative CBF of the contralateral hemisphere in the two groups. Neverthless, this study addresses an important and commonly encountered question regarding the safety of aggressive BP lowering in the acute phase in ICH patients.
Post-stroke seizures, especially in the acute phase is a relatively well described and understood entity, but the incidence of post-stroke epilepsy, especially in the long term is far less thoroughly studied. In this interesting population-based study, Graham et al. investigate the epidemiology and associations of post-stroke epilepsy utilizing data collected over a 12-year period in the South London Stroke Register of first strokes.
Despite several limitations, most importantly the fact that the diagnosis of epilepsy was self-reported and not confirmed by a physician, the study offers provides potentially useful information both for patients and physicians and more importantly underlines the need for prospective studies possibly including prophylactic antiepileptic treatment post-stroke.