Embolic Agent Choice in Middle Meningeal Artery Embolization as Primary or Adjunct Treatment for Chronic Subdural Hematoma: A Systematic Review and Meta-analysis.

BACKGROUND: Middle meningeal artery embolization is an emerging treatment option for chronic subdural hematomas. PURPOSE: Our aim was to assess outcomes following middle meningeal artery embolization by different techniques, including in comparison with traditional surgical methods. DATA SOURCES: We searched the literature databases from inception to March 2022. DATA SELECTION: We selected studies reporting outcomes after middle meningeal artery embolization as a primary or adjunctive treatment for chronic subdural hematoma. DATA ANALYSIS: We analyzed the risk of recurrence of chronic subdural hematoma, reoperation for recurrence or residual hematoma, complications, and radiologic and clinical outcomes using random effects modeling. Additional analyses were performed on the basis of whether middle meningeal artery embolization was used as the primary or adjunct treatment and by embolic agent type. DATA SYNTHESIS: Twenty-two studies were included with 382 patients with middle meningeal artery embolization and 1373 surgical patients. The rate of subdural hematoma recurrence was 4.1%. Fifty (4.2%) patients underwent a reoperation for a recurrent or residual subdural hematoma. Thirty-six (2.6%) experienced postoperative complications. The rates of good radiologic and clinical outcomes were 83.1% and 73.3%, respectively. Middle meningeal artery embolization was significantly associated with decreased odds of subdural hematoma reoperation (OR = 0.48; 95% CI, 23.4-99.1; P = .047) compared with surgery. The lowest rates of subdural hematoma radiologic recurrence, reoperation, and complications were observed among patients receiving embolization with Onyx, whereas good overall clinical outcome occurred most commonly with combined polyvinyl alcohol and coils. LIMITATIONS: A limitation was the retrospective design of studies included. CONCLUSIONS: Middle meningeal artery embolization is safe and effective, either as a primary or adjunctive treatment. Treatment using Onyx seems to yield lower rates of recurrence, rescue operation, and complications whereas particles and coils produce good overall clinical outcomes.

Learning Curve for Flow Diversion of Posterior Circulation Aneurysms: A Long-Term International Multicenter Cohort Study.

BACKGROUND AND PURPOSE: Flow diversion has gradually become a standard treatment for intracranial aneurysms of the anterior circulation. Recently, the off-label use of the flow diverters to treat posterior circulation aneurysms has also increased despite initial concerns of rupture and the suboptimal results. This study aimed to explore the change in complication rates and treatment outcomes across time for posterior circulation aneurysms treated using flow diversion and to further evaluate the mechanisms and variables that could potentially explain the change and outcomes. MATERIALS AND METHODS: A retrospective review using a standardized data set at multiple international academic institutions was performed to identify patients with ruptured and unruptured posterior circulation aneurysms treated with flow diversion during a decade spanning January 2011 to January 2020. This period was then categorized into 4 intervals. RESULTS: A total of 378 procedures were performed during the study period. Across time, there was an increasing tendency to treat more vertebral artery and fewer large vertebrobasilar aneurysms (P = .05). Moreover, interventionalists have been increasingly using fewer overlapping flow diverters per aneurysm (P = .07). There was a trend toward a decrease in the rate of thromboembolic complications from 15.8% in 2011-13 to 8.9% in 2018-19 (P = .34). CONCLUSIONS: This multicenter experience revealed a trend toward treating fewer basilar aneurysms, smaller aneurysms, and increased usage of a single flow diverter, leading to a decrease in the rate of thromboembolic and hemorrhagic complications.

Do Outcomes between Women and Men Differ after Endovascular Thrombectomy? A Meta-analysis.

BACKGROUND: Research on the presence of sex-based differences in the outcomes of patients undergoing endovascular thrombectomy for acute ischemic stroke has reached differing conclusions. PURPOSE: This review aimed to determine whether sex influences the outcome of patients with large-vessel occlusion stroke undergoing endovascular thrombectomy. STUDY SELECTION: We performed a systematic review and meta-analysis of endovascular thrombectomy studies with either stratified cohort outcomes according to sex (females versus males) or effect size reported for the consequence of sex versus outcomes. We included 33 articles with 7335 patients. DATA ANALYSIS: We pooled ORs for the 90-day mRS score, 90-day mortality, symptomatic intracranial hemorrhage, and recanalization. DATA SYNTHESIS: Pooled 90-day good outcomes (mRS ≤ 2) were better for men than women (OR = 1.29; 95% CI, 1.09-1.53; P = <.001, I2 = 56.95%). The odds of the other outcomes, recanalization (OR = 0.94; 95% CI, 0.77-1.15; P = .38, I2 = 0%), 90-day mortality (OR = 1.11; 95% CI, 0.89-1.38; P = .093, I2 = 0%), and symptomatic intracranial hemorrhage (OR = 1.40; 95% CI, 0.99-1.99; P = .069, I2 = 0%) were comparable between men and women. LIMITATIONS: Moderate heterogeneity was found. Most studies included were retrospective in nature. In addition, the randomized trials included were not specifically designed to compare outcomes between sexes. CONCLUSIONS: Women undergoing endovascular thrombectomy for large-vessel occlusion have inferior 90-day clinical outcomes. Sex-specific outcomes should be investigated further in future trials as well as pathophysiologic studies.

Endovascular Cerebral Venous Sinus Imaging with Optical Coherence Tomography.

BACKGROUND AND PURPOSE: Imaging of the cerebral venous sinuses has evolved Substantially during the past 2 decades, and most recently intravascular sinus imaging with sonography has shed light on the pathophysiology of sinus thrombosis and intracranial hypertension. Optical coherence tomography is the highest resolution intravascular imaging technique available but has not been previously used in cerebral sinus imaging. The purpose of this study was to develop a preclinical animal model of endovascular optical coherence tomography cerebral venous sinus imaging and compare optical coherence tomography findings with histology. MATERIALS AND METHODS: Four consecutive Yorkshire swine were selected. The superior sagittal sinus was first catheterized with a microwire, and the optical coherence tomography catheter was delivered via a monorail technique into the sinus. Luminal blood was cleared with a single arterial injection. After structural and Doppler optical coherence tomography imaging, a craniotomy was performed and the sinus and adjacent dura/veins were resected. Bland-Altman analysis was performed to compare optical coherence tomography and histology. RESULTS: Technically successful optical coherence tomography images were obtained in 3 of 4 swine. The luminal environment and visualization of dural arteries and draining cortical veins were characterized. The average maximum diameters of the sinus, dural arteries, and cortical veins were 3.14 mm, 135 µm, and 260 µm, respectively. Bland-Altman analysis demonstrated good agreement between histology and optical coherence tomography images. CONCLUSIONS: Endovascular optical coherence tomography imaging was feasible in this preclinical animal study. Adoption of this imaging technique in the human cerebral venous sinus could aid in the diagnosis, treatment, and understanding of the pathophysiology of various diseases of the sinus. Human safety and feasibility studies are needed.

Imaging the electro-kinetic response of biological tissues with optical coherence tomography.

We demonstrate the feasibility of using optical coherence tomography (OCT) to detect and image an electro-kinetic response: electric-field induced optical changes (EIOC) in soft biological tissues. A low-frequency electric field was applied to ex vivo samples of porcine heart tissues, while OCT signals were acquired continuously. Experimental results show that the amplitude of the OCT signal change is proportional to the amplitude and inversely proportional to the frequency of the applied electric field. We show that the nonconductive component of the sample was eliminated in the normalized EIOC image. To the best our knowledge, this is the first time a two-dimensional image related to the electro-kinetic response of soft tissues is obtained with depth resolution. Since electro-kinetic properties can change during cancerogenesis, EIOC imaging can potentially be used for cancer detection.

Vascular wall imaging of vulnerable atherosclerotic carotid plaques: current state of the art and potential future of endovascular optical coherence tomography.

As stroke is one of the leading causes of death and long-term morbidity worldwide, the research community has studied cardiac embolic sources, as well as vessel wall pathologies. For the latter, attention has been focused on defining morphologic tissue features associated with catastrophic events stemming from the carotid artery. Multiple noninvasive imaging modalities are currently being used to image and classify carotid atherosclerotic plaques, such as MR imaging, CT, and sonography, in an effort to provide clinically relevant predictive metrics for use in patient risk stratification and to define appropriate treatment options. This article compares and contrasts these existing clinical imaging modalities along with discussion of a new endovascular technique originally developed for cardiology, OCT, with which 3D comprehensive high-resolution images of the arterial wall can be acquired.

In vivo real time monitoring of vasoconstriction and vasodilation by a combined diffuse reflectance spectroscopy and Doppler optical coherence tomography approach.

BACKGROUND AND OBJECTIVES: A combined diffuse reflectance (DR) spectroscopy and doppler optical coherence tomography (DOCT) approach may offer a powerful means for assessment of tissue function, and potentially provide a way for earlier cancer detection through non-invasive local blood supply measurements. The goal of the study was to compare a DR-derived blood-content-related index to a measure of local blood supply flow as furnished by DOCT during manipulations with blood circulation (vasoconstriction and vasodilation), investigate similarities and differences, complementarity of techniques, and then applying these results to the underlying biology. STUDY DESIGN/MATERIALS AND METHODS: Simultaneous DR-DOCT measurements of local blood supply were conducted during drug and mechanically-induced vasoconstriction and vasodilatation on an externalized intact rat gut in vivo. A simple heuristic metric, termed Blood Supply Index was derived from the spectroscopic DR data. This metric variance due to mechanical and pharmacological manipulation of the local blood supply was recorded, and compared with that of two DOCT-derived metrics, namely normalized blood velocity (v(rel)) and blood vessel diameter (D). SUMMARY AND CONCLUSIONS: During vasoconstriction and vasodilatation, the local blood response was successfully visualized by both DOCT and DR metrics and a reproducible correlation was found between these two measurements. A combined DR-DOCT approach may evolve into a technologically-viable method for cross-validation of the derived haemodynamic metrics, yielding a more reliable functional tissue assessment tool for accurate cancer diagnosis and staging.