Brinjikji, Waleed

Spinal cord intramedullary arteriovenous malformations (AVMs) have classically been considered congenital lesions that are present from birth. The reason for this dogmatic principal is the fact that a vast majority of these lesions present in pediatric and young adult patients. Interestingly, while many authors have demonstrated the development of de novo nidus-type brain AVMs, there have been no reported cases of a de novo intramedullary or perimedullary AVM of the spine. In this paper the authors describe what they believe to be the first reported case of a de novo AVM of the spinal cord in a young patient who underwent serial imaging from birth for evaluation of a syrinx. Potential pathophysiological mechanisms for the development of de novo vascular malformations of the spinal cord are discussed.

Background and purpose Thromboembolic events are recognized complications of aneurysm coiling. Objective To identify any protective effects of antiplatelet therapy use before coiling of unruptured aneurysms. Methods We conducted a meta-analysis of clinical studies published up to February 2019. We included studies reporting symptomatic thromboembolic events (defined as clinical stroke or transient ischemic attacks) in patients who received antiplatelet therapy before coiling of unruptured aneurysms using unassisted coiling, balloon assistance, or multiple microcatheters. We excluded ruptured aneurysms and those treated with stent coiling or flow diverters. Results We identified 14 studies (2486 patients). All were single-center studies and four were prospective. In three studies with a control (no treatment) arm, the pooled risk ratio for symptomatic thromboembolic events with versus without antiplatelet therapy was 0.33 (95% CI 0.17 to 0.92, p= 0.035). The cumulative risk of symptomatic thromboembolic events with single antiplatelet agents was 5.0% ‘56/1122’ (95% CI 1.6% to 8.4%, I283.63%), and with dual or multiple agents 2.7% ‘33/1237’ (95% CI 1.0% to 3.0%, I239.9%). The incidence of diffusion lesions was reported in seven studies. It was 50.5% ‘96/190’ (95% CI 7.3% to 93.9%, I294.4%) with single agents compared with 43.9% ‘196/446’ (95% CI 25.9% to 61.9%, I273.4%) with dual or multiple agents. Conclusion Periprocedural antiplatelet therapy was associated with a low symptomatic thromboembolic event after coiling-only for unruptured aneurysms. However, available evidence is of limited quality with significant heterogeneity, requiring evidence from randomized controlled trials.

OBJECTIVEDelayed cerebral ischemia (DCI) and aneurysm rebleeding contribute to morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH); however, the relationship between their impacts on overall functional outcome is incompletely understood.METHODSThe authors conducted a cohort study of all aSAH during the study period from 2001 to 2016. Primary end points were overall functional outcome and ischemic aSAH sequelae, defined as delayed cerebral ischemia (DCI), DCI with infarction, symptomatic vasospasm (SV), and global cerebral edema (GCE). Outcomes were compared between the rebleed and nonrebleed cohorts overall and after propensity-score matching (PSM) for risk factors and treatment modality. Univariate and multivariate ordered logistic regression analyses for functional outcomes were performed in the PSM cohort to identify predictors of poor outcome.RESULTSFour hundred fifty-five aSAH cases admitted within 24 hours of aneurysm rupture were included, of which 411 (90%) experienced initial aneurysm ruptures only, while 44 (10%) had clinically confirmed rebleeding. In the overall cohort, rebleeding was associated with significantly worse functional outcome, longer intensive care unit length of stay (LOS), and GCE (all p < 0.01); treatment modality, overall LOS, DCI, DCI with infarction, and SV were nonsignificant. In the PSM analysis of 43 matched rebleed and 43 matched nonrebleed cases, only poor functional outcome and GCE remained significantly associated with rebleeding (p < 0.01 and p = 0.02, respectively). Multivariate regression identified that both rebleeding (HR 21.5, p < 0.01) and DCI (HR 10.1, p = 0.01) independently predicted poor functional outcome.CONCLUSIONSRebleeding and DCI after aSAH are highly morbid and potentially deadly events after aSAH, which appear to have independent negative impacts on overall functional outcome. Early rebleeding did not significantly affect the risk of delayed ischemic complications.

Abstract Flow diverters have drastically changed the landscape of intracranial aneurysm treatment and are now considered first-line therapy for select lesions. Their mechanism of action relies on intrinsic alteration in hemodynamic parameters, both at the parent artery and within the aneurysm sac. Moreover, the device struts act as a nidus for endothelial cell growth across the aneurysm neck ultimately leading to aneurysm exclusion from the circulation. In silico computational analyses and investigations in preclinical animal models have provided valuable insights into the underlying biological basis for flow diverter therapy. Here, we review the present understanding pertaining to flow diverter biology and mechanisms of action, focusing on stent design, induction of intra-aneurysmal thrombosis, endothelialization, and alterations in hemodynamics.

Background and Purpose— Racial and ethnic disparities in the access to mechanical thrombectomy (MT) for treatment of acute ischemic stroke (AIS) secondary to large vessel occlusion have been previously described. The effect of recent randomized trials validating MT as an effective therapy for AIS secondary to large vessel occlusion on such disparities has not been investigated. Methods— Information on admissions for AIS to endovascular centers occurring between January 2016 and September 2018 was obtained from a national database. The number of patients receiving IV-tPA (intravenous tissue-type plasminogen activator) and MT at each institution was determined, and patient demographics were characterized according to age, sex, race/ethnicity, and insurance status. Comparisons of patients who did and did not undergo MT and between patients of different racial and ethnic backgrounds were performed. Demographic variables independently associated with the utilization of MT were identified using multivariate linear regression analysis. Results— There were 206 853 admissions to 173 endovascular centers during the time period of interest. The overall utilization of MT was 8.4%. The utilization of MT for black/Hispanic patients was lower than that among white/non-Hispanic patients (7.0% versus 9.8%; P <0.001). Black/Hispanic patients were also less likely to receive IV-tPA (16.2% versus 20.5%; P <0.001) and to be admitted to the endovascular center after transfer from a different hospital (20.0% versus 30.1%; P <0.001). On multivariate linear regression analysis, increasing institutional proportions of patients with female sex (β=−0.601; P <0.001), insurance with Medicaid or uninsured status (β=−0.153; P =0.029), and black/Hispanic race/ethnicity (β=−0.062; P =0.046) were independently associated with lower institutional utilization of MT. Conclusions— Despite the mainstream acceptance of MT for the treatment of AIS secondary to large vessel occlusion, racial and ethnic disparities in the utilization of MT persist.

Background Clot perviousness in large vessel occlusion has been shown to be associated with improved recanalization outcomes with mechanical thrombectomy and intravenous thrombolysis. Objective To evaluate the association between clot perviousness based on thrombus attenuation increase (TAI) on CT, and histologic composition of clots in acute ischemic stroke (AIS). Methods A retrospective review was completed of patients with AIS secondary to large vessel occlusion, non-contrast CT (NCCT) and CT angiography (CTA) images, and histologic analysis of the retrieved clot. TAI was measured by subtracting clot attenuation on NCCT from the attenuation on CTA. Up to 3 regions of interest (ROIs) were evaluated on each clot; the average attenuation was used for analysis if multiple ROIs were assessed. Pervious clots were defined as TAI ≥10 Hounsfield units (HUs); impervious clots had TAI <10 HU. Histopathologic analyses of clots were assessed for relative compositions of red blood cells (RBCs), white blood cells (WBCs), fibrin, and platelets/other. Results 57 patients were included. Pervious clots were more likely to be RBC rich (p=0.04); impervious clots were more likely to be fibrin and WBC rich (p=0.01 for both). Pervious clots also had greater RBC density than impervious clots (49.8% and 33.0%, respectively; p=0.006); fibrin density of pervious clots was lower than that of impervious clots (17.8% and 23.2%, respectively; p=0.02). Conclusion Clot perviousness, assessed on NCCT and CTA imaging, is associated with higher RBC density and lower fibrin density, offering a possible explanation for the higher rates of successful thrombectomy and favorable clinical outcome seen in such patients.