Nestor Gonzalez

Impact of Anatomic Features in the Endovascular Embolization of 181 Anterior Communicating Artery Aneurysms

Background and Purpose— We analyzed the impact of detailed anatomic characteristics on the results of endovascular coil embolization for anterior communicating artery (AcoA) aneurysms and developed a predictive model estimating the probability of successful endovascular treatment. Methods— One hundred eighty-one AcoA aneurysms were treated with endovascular coil embolization between August 1991 and November 2005. Morphological characteristics that were analyzed included direction of the dome, location of the neck, association with hypoplasia or aplasia of AcoA complex vessels, sac, and neck size. Immediate clinical and anatomic results, long-term morbidity/mortality, recanalization rate, and delayed aneurysm thrombosis were analyzed. ORs were calculated for each anatomic and clinical result and logistic regression was used in formulating a predictive model. Results— There were 115 females and 66 males. Age range was 9 to 86 years (mean 57). Factors significantly associated with complete embolization included small aneurysms (<10 mm), small neck (<4 mm), and anterior dome orientation. Factors significantly associated with aneurysm recanalization after long-term follow-up included aneurysm domes >10 mm, neck location on the AcoA, posterior dome orientation, and incomplete original embolization. Globally, the majority of patients remained neurologically intact or unchanged after the procedure (92.8%). Mortality was significantly influenced by the preoperative condition of the patient. The predictive model successfully represented the likely outcomes based on morphological features. Conclusions— AcoA aneurysm coil embolization can be safely performed with acceptable rates of morbidity. Dome and neck orientation, sack and neck size, sac-to-neck ratio, and associated anomalies should be considered to accurately assess the probability of successful treatment for AcoA aneurysms.

Endovascular coiling of intracranial aneurysms in elderly patients: report of 205 treated aneurysms.

BACKGROUNDMore elderly patients are presenting with intracranial aneurysms. Many are poor surgical candidates and often undergo endovascular treatment. OBJECTIVEWe present our experience with embolization in elderly patients. METHODSWe performed a retrospective review of a prospective database of elderly patients treated with coil embolization for intracranial aneurysms. RESULTSIn a period of 16 years, 205 aneurysms were treated in 196 individuals (age range, 70–96 years; mean age, 77.3 years), including 159 females (average follow-up, 16.2 months). Ninety-seven patients presented with unruptured aneurysms, and 99 patients presented after subarachnoid hemorrhage; the diagnosis was confirmed by computed tomographic scan or lumbar puncture. Complete occlusion was achieved in 53 aneurysms (26%), with a neck remnant in 127 (62%), incomplete occlusion in 13 (6%), and 12 unsuccessful attempts. Postembolization, 89.3% of patients were neurologically intact or unchanged, whereas 8.7% had new deficits. Four patients died. By modified Rankin Scale score, at last clinical evaluation, 128 patients (65%) had a good outcome. Follow-up angiograms were available for 113 aneurysms; they revealed that 62% were unchanged, 21% were further thrombosed, and 17% had recanalized. Three aneurysms ruptured after treatment during follow-up. Rupture was not associated with incomplete occlusion or neck remnant results (P = .6). Twenty-five aneurysms required reembolization. Reembolization was not associated with new deficits or death (odds ratio, 0.56; 95% confidence interval, 0.19–1.58; P = .27). CONCLUSIONCoil embolization of intracranial aneurysms is safe and effective in the elderly. Preembolization clinical condition strongly correlates with clinical outcome. Incomplete embolizations are not associated with a higher rerupture risk. Additional embolization does not affect the clinical results.

Higher rates of mortality but not morbidity follow intracranial mechanical thrombectomy in the elderly.

BACKGROUND AND PURPOSE: Mechanical thrombectomy is a promising means of recanalizing acute cerebrovascular occlusions in certain situations. We sought to determine if increasing age adversely affects prognosis. MATERIALS AND METHODS: We reviewed all Merci thrombectomy cases and compared patients younger than 80 years of age with older individuals. We compared these 2 age groups with respect to recanalization rates, hospital LOS, hemorrhagic transformation, and death and disability on discharge. RESULTS: Elderly patients were more likely to die from their stroke than those younger than 80 years of age, regardless of recanalization success (48% versus 15%; OR, 5.5; 95% CI, 2.1–14.1). Among survivors, there was no difference in the probability of having a good functional outcome (mRS, ≤2) by discharge (38% versus 40%; OR, 0.9; 95% CI, 0.3–2.8). Hemorrhagic transformation did not vary between age groups. CONCLUSIONS: Among patients undergoing mechanical thrombectomy for acute cerebrovascular occlusions, increased age conveys a higher rate of stroke-related death, but disability at discharge in this group is similar to that of younger survivors.

Recanalization Rates Decrease with Increasing Thrombectomy Attempts

BACKGROUND AND PURPOSE: Use of the Merci retriever is increasing as a means to reopen large intracranial arterial occlusions. We sought to determine whether there is an optimum number of retrieval attempts that yields the highest recanalization rates and after which the probability of success decreases. MATERIALS AND METHODS: All consecutive patients undergoing Merci retrieval for large cerebral artery occlusions were prospectively tracked at a comprehensive stroke center. We analyzed ICA, M1 segment of the MCA, and vertebrobasilar occlusions. We compared the revascularization of the primary AOL with the number of documented retrieval attempts used to achieve that AOL score. For tandem lesions, each target lesion was compared separately on the basis of where the device was deployed. RESULTS: We identified a total of 97 patients with 115 arterial occlusions. The median number of attempts per target vessel was 3, while the median final AOL score was 2. Up to 3 retrieval attempts correlated with good revascularization (AOL 2 or 3). When ≥4 attempts were performed, the end result was more often failed revascularization (AOL 0 or 1) and procedural complications (P = .006). CONCLUSIONS: In our experience, 3 may be the optimum number of Merci retrieval attempts per target vessel occlusion. Four or more attempts may not improve the chances of recanalization, while increasing the risk of complications.

Effects of mobile and digital support for a structured, competency-based curriculum in neurosurgery residency education.

BACKGROUNDnChanges in neurosurgical practice and graduate medical education impose new challenges for training programs.nnnOBJECTIVEnWe present our experience providing neurosurgical residents with digital and mobile educational resources in support of the departmental academic activities.nnnMETHODSnA weekly mandatory conference program for all clinical residents based on the Accreditation Council for Graduate Medical Education competencies, held in protected time, was introduced. Topics were taught through didactic sessions and case discussions. Faculty and residents prepare high-quality presentations, equivalent to peer-review leading papers or case reports. Presentations are videorecorded, stored in a digital library, and broadcasted through our Website and iTunes U. Residents received mobile tablet devices with remote access to the digital library, applications for document/video management, and interactive teaching tools.nnnRESULTSnResidents responded to an anonymous survey, and performances on the Self-Assessment in Neurological Surgery examination before and after the intervention were compared. Ninety-two percent reported increased time used to study outside the hospital and attributed the habit change to the introduction of mobile devices; 67% used the electronic tablets as the primary tool to access the digital library, followed by 17% hospital computers, 8% home computers, and 8% personal laptops. Forty-two percent have submitted operative videos, cases, and documents to the library. One year after introducing the program, results of the Congress of Neurological Surgeons-Self-Assessment in Neurological Surgery examination showed a statistically significant improvement in global scoring and improvement in 16 of the 18 individual areas evaluated, 6 of which reached statistical significance.nnnCONCLUSIONnA structured, competency-based neurosurgical education program supported with digital and mobile resources improved reading habits among residents and performance on the Congress of Neurological Surgeons-Self-Assessment in Neurological Surgery examination.

The Risk of Acute Radiocontrast-Mediated Kidney Injury Following Endovascular Therapy for Acute Ischemic Stroke Is Low

BACKGROUND AND PURPOSE: Endovascular therapy is an alternative for the treatment of AIS resulting from large intracranial arterial occlusions that depends on the use of iodinated RCM. The risk of RCM-mediated AKI following endovascular therapy for AIS may be different from that following coronary interventions because patients may not have identical risk factors. MATERIALS AND METHODS: All consecutive patients with large-vessel AIS undergoing endovascular therapy were prospectively recorded. We recorded the baseline kidney function, and RCM-AKI was assessed according to the AKIN criteria at 48 hours after RCM administration. We compared the rate of RCM-AKI 48 hours after the procedure and sought to determine whether any preexisting factors increased the risk of RCM-AKI. RESULTS: We identified 99 patients meeting inclusion criteria. The average volume of contrast was 189 ± 71 mL, and the average creatinine change was −4.6% at 48 hours postangiography. There were 3 patients with RCM-AKI. Although all 3 patients died as a result of their strokes, return to baseline creatinine levels occurred before death. There was a trend toward higher rates of premorbid diabetes mellitus, chronic renal insufficiency, preadmission statin and NSAID use, and a higher serum creatinine level on admission for the RCM-AKI group. The volume of procedural contrast was similar between groups (those with and those without RCM-AKI) (P = .5). CONCLUSIONS: In this small study, the rate of RCM-AKI following endovascular intervention for AIS was very low. A much larger study is required to determine its true incidence.

Incomplete mechanical recanalization of middle cerebral artery occlusions facilitates endogenous recanalization within 5 h

Background and purpose Successful revascularization can often improve functional outcome after large intracranial arterial occlusions. However, incomplete or unsuccessful recanalization is often the end result after attempted mechanical thrombectomy. A study was undertaken to determine whether partial recanalization of proximal isolated middle cerebral artery (MCA) occlusions facilitates endogenous thrombolysis and spontaneous recanalization. Methods We retrospectively analyzed consecutive patients with acute ischemic stroke undergoing mechanical thrombectomy using the Merci Retriever System for occlusions involving any portion of the M1 segment of the MCA. Only those patients with a residual obstruction of the proximal MCA segments were included. The rates of facilitated endogenous recanalization (FER5) by imaging within the 5u2005h following intervention were compared in patients with partial proximal recanalization and those in whom recanalization was unsuccessful. Results Forty-two patients were included in the analysis. Twenty-six patients had good recanalization of the proximal aspect of the target lesion with an arterial occlusive lesion score of 2 or 3 but a residual partial or total occlusion of the MCA, while 16 patients failed to recanalize any portion of the target occlusion. Twelve patients (46%) in the first group and only one (5.9%) in the second group had facilitated endogenous recanalization on interval imaging 5u2005h after intervention (OR 12.9, 95% CI 1.5 to 112.2). Nine patients with proximal recanalization had good clinical outcomes at discharge (mRS ≤2) compared with none without recanalization (p=0.01), but FER did not have a relationship with clinical outcome. Conclusions Despite initially incomplete proximal mechanical thrombectomy, nearly half of all patients with residual M1 occlusions will undergo further endogenous recanalization within the subsequent 5u2005h.

P-003 Baseline DWI volume predicts successful recanalization in multimodal endovascular therapy for acute ischemic stroke

Background Effective reperfusion is associated with better outcome from acute cerebral ischemia. The pre-intervention clinical and imaging predictors of procedural success in patients treated with multimodal mechanical device strategies (Merci ± Penumbra ± angioplasty and stenting) have not been well delineated. Methods In a prospectively maintained database, we analyzed consecutive patients with acute ICA and M1 occlusions treated with endovascular recanalization following MRI. We investigated the pretreatment clinical and imaging factors associated with substantial recanalization (TICI≥2b) and clinical outcome. Results Among 105 patients meeting study entry criteria, mean age was 66.6 (±17.8). 65 % were female, median pretreatment NIHSS was 18 (range 2–31), mean baseline DWI volume was 30.6u2009cc (SD±35.1), and mean time to groin puncture was 412u2009min (SD±207.6). The median number of mechanical device passes was two (range 0–8). 73 (70%) patients were treated with a single device. IV tPA was used in 43 patients (41%). Substantial recanalization occurred in 43 patients (41%). The strongest predictors of poor outcome (mRS >3 at discharge) were high baseline NIHSS (OR 0.87; p<0.001) and presence of SAH after the procedure (OR 0.05; p=0.001). However, the presence of SAH did not correlate with the number of attempts or devices used. The strongest predictor of better outcome at discharge (mRS ≤3) was substantial recanalization (TICI≥2b). Time to groin puncture, number of device passes, single vs multiple device therapy, adjunctive IV TPA, or arterial occlusion site did not correlate substantial recanalization. In the final logistic regression multivariate analysis, among all baseline clinical and imaging variables considered, the pre-treatment DWI volume was the only factor associated with a substantial recanalization (OR 0.238; p=0.046). Conclusions Baseline DWI lesion volume is a potent predictor of substantial reperfusion in multimodal endovascular therapy for acute ischemic stroke. This finding suggests that the effectiveness of the reperfusion therapy is likely influenced by much more complex pathophysiological mechanism, rather than mechanical and/or anatomical factors alone. Competing interests None.

Disappearance of a small intracranial aneurysm as a result of vessel straightening and in-stent stenosis following use of an Enterprise vascular reconstruction device

In-stent stenosis after stent-assisted coil embolization is a rare but well-known complication. A 32-year-old woman with an unruptured wide-necked left internal carotid artery (ICA) terminus aneurysm and an ipsilateral very small anterior choroidal artery aneurysm underwent stent-assisted coil embolization for the ICA terminus aneurysm. The 4-month follow-up angiography revealed diffuse in-stent stenosis and disappearance of the untreated anterior choroidal artery aneurysm, retaining the patency of the anterior choroidal artery. To our knowledge, this is the first report to demonstrate the course of in-stent stenosis and disappearance of an untreated small intracranial aneurysm as a result. We report this unique case and discuss the interesting mechanism underlying this phenomenon, and also provide a review of the relevant literature.