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Yosuf W. Subat, Hormuzdiyar H. Dasenbrock, Bradley A. Gross, Nirav J. Patel, Kai U. Frerichs, Rose Du, and M. Ali Aziz-Sultan

OBJECTIVE

The primary goal of the treatment of cerebral arteriovenous malformations (AVMs) is angiographic occlusion to eliminate future hemorrhage risk. Although multimodal treatment is increasingly used for AVMs, periprocedural hemorrhage after transarterial embolization is a potential endovascular complication that is only partially understood and merits quantification.

METHODS

Searching the period between 1990 and 2019, the authors of this meta-analysis queried the PubMed and Embase databases for studies reporting periprocedural hemorrhage (within 30 days) after liquid embolization (using cyanoacrylate or ethylene vinyl alcohol copolymer) of AVMs. Random effects meta-analysis was used to evaluate the pooled rate of flow-related hemorrhage (those attributed to alterations in AVM dynamics), technical hemorrhage (those related to procedural complications), and total hemorrhage. Meta-regression was used to analyze the study-level predictors of hemorrhage, including patient age, Spetzler-Martin grade, hemorrhagic presentation, embolysate used, intent of treatment (adjuvant vs curative), associated aneurysms, endovascular angiographic obliteration, year of study publication, and years the procedures were performed.

RESULTS

A total of 98 studies with 8009 patients were included in this analysis, and the mean number of embolization sessions per patient was 1.9. The pooled flow-related and total periprocedural hemorrhage rates were 2.0% (95% CI 1.5%–2.4%) and 2.6% (95% CI 2.1%–3.0%) per procedure and 3.4% (95% CI 2.6%–4.2%) and 4.8% (95% CI 4.0%–5.6%) per patient, respectively. The mortality and morbidity rates associated with hemorrhage were 14.6% and 45.1%, respectively. Subgroup analyses revealed a pooled total hemorrhage rate per procedure of 1.8% (95% CI 1.0%–2.5%) for adjuvant (surgery or radiosurgery) and 4.6% (95% CI 2.8%–6.4%) for curative intent. The treatment of aneurysms (p = 0.04) and larger patient populations (p < 0.001) were significant predictors of a lower hemorrhage rate, whereas curative intent (p = 0.04), angiographic obliteration achieved endovascularly (p = 0.003), and a greater number of embolization sessions (p = 0.03) were significant predictors of a higher hemorrhage rate. There were no significant differences in periprocedural hemorrhage rates according to the years evaluated or the embolysate utilized.

CONCLUSIONS

In this study-level meta-analysis, periprocedural hemorrhage was seen after 2.6% of transarterial embolization procedures for cerebral AVMs. The adjuvant use of endovascular embolization, including in the treatment of associated aneurysms and in the presurgical or preradiosurgical setting, was a study-level predictor of significantly lower hemorrhage rates, whereas more aggressive embolization involving curative intent and endovascular angiographic obliteration was a predictor of a significantly higher total hemorrhage rate.

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Hormuzdiyar H. Dasenbrock, Robert F. Rudy, Timothy R. Smith, William B. Gormley, Nirav J. Patel, Kai U. Frerichs, M. Ali Aziz-Sultan, and Rose Du

OBJECTIVE

The complex decision analysis of unruptured intracranial aneurysms entails weighing the benefits of aneurysm repair against operative risk. The goal of the present analysis was to build and validate a predictive scale that identifies patients with the greatest odds of a postsurgical adverse event.

METHODS

Data on patients who underwent surgical clipping of an unruptured aneurysm were extracted from the prospective National Surgical Quality Improvement Program registry (NSQIP; 2007–2014); NSQIP does not systematically collect data on patients undergoing intracranial endovascular intervention. Multivariable logistic regression evaluated predictors of any 30-day adverse event; variables screened included patient demographics, comorbidities, functional status, preoperative laboratory values, aneurysm location/complexity, and operative time. A predictive scale was constructed based on statistically significant independent predictors, which was validated using both NSQIP (2015–2016) and the Nationwide Inpatient Sample (NIS; 2002–2011).

RESULTS

The NSQIP unruptured aneurysm scale was proposed: 1 point was assigned for a bleeding disorder; 2 points for age 51–60 years, cardiac disease, diabetes mellitus, morbid obesity, anemia (hematocrit < 36%), operative time 240–330 minutes; 3 points for leukocytosis (white blood cell count > 12,000/μL) and operative time > 330 minutes; and 4 points for age > 60 years. An increased score was predictive of postoperative stroke or coma (NSQIP: p = 0.002, C-statistic = 0.70; NIS: p < 0.001, C-statistic = 0.61), a medical complication (NSQIP: p = 0.01, C-statistic = 0.71; NIS: p < 0.001, C-statistic = 0.64), and a nonroutine discharge (NSQIP: p < 0.001, C-statistic = 0.75; NIS: p < 0.001, C-statistic = 0.66) in both validation populations. Greater score was also predictive of increased odds of any adverse event, a major complication, and an extended hospitalization in both validation populations (p ≤ 0.03).

CONCLUSIONS

The NSQIP unruptured aneurysm scale may augment the risk stratification of patients undergoing microsurgical clipping of unruptured cerebral aneurysms.

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Michael A. Silva, Alfred P. See, Hormuzdiyar H. Dasenbrock, Ramsey Ashour, Priyank Khandelwal, Nirav J. Patel, Kai U. Frerichs, and Mohammad A. Aziz-Sultan

Successful application of endovascular neurosurgery depends on high-quality imaging to define the pathology and the devices as they are being deployed. This is especially challenging in the treatment of complex cases, particularly in proximity to the skull base or in patients who have undergone prior endovascular treatment. The authors sought to optimize real-time image guidance using a simple algorithm that can be applied to any existing fluoroscopy system. Exposure management (exposure level, pulse management) and image post-processing parameters (edge enhancement) were modified from traditional fluoroscopy to improve visualization of device position and material density during deployment. Examples include the deployment of coils in small aneurysms, coils in giant aneurysms, the Pipeline embolization device (PED), the Woven EndoBridge (WEB) device, and carotid artery stents. The authors report on the development of the protocol and their experience using representative cases.

The stent deployment protocol is an image capture and post-processing algorithm that can be applied to existing fluoroscopy systems to improve real-time visualization of device deployment without hardware modifications. Improved image guidance facilitates aneurysm coil packing and proper positioning and deployment of carotid artery stents, flow diverters, and the WEB device, especially in the context of complex anatomy and an obscured field of view.