Bernard R. Bendok

Prediction of Cerebral Vasospasm in Patients Presenting with Aneurysmal Subarachnoid Hemorrhage: A Review

OBJECTIVE:Cerebral vasospasm is a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been treated. A substantial amount of experimental and clinical research has been conducted in an effort to predict and prevent its occurrence. This research has contributed to significant advances in the understanding of the mechanisms leading to cerebral vasospasm. The ability to accurately and consistently predict the onset of cerebral vasospasm, however, has been challenging. This topic review describes the various methodologies and approaches that have been studied in an effort to predict the occurrence of cerebral vasospasm in patients presenting with SAH. METHODS:The English-language literature on the prediction of cerebral vasospasm after aneurysmal SAH was reviewed using the MEDLINE PubMed (1966–present) database. RESULTS:The risk factors, diagnostic imaging, bedside monitoring approaches, and pathological markers that have been evaluated to predict the occurrence of cerebral vasospasm after SAH are presented. CONCLUSION:To date, a large blood burden is the only consistently demonstrated risk factor for the prediction of cerebral vasospasm after SAH. Because vasospasm is such a multifactorial problem, attempts to predict its occurrence will probably require several different approaches and methodologies, as is done at present. Future improvements in the prevention of cerebral vasospasm from aneurysmal SAH will most likely require advances in our understanding of its pathophysiology and our ability to predict its onset.

Reduced Platelet Activity Is Associated With Early Clot Growth and Worse 3-Month Outcome After Intracerebral Hemorrhage

Background and Purpose— Antiplatelet medication use and reduced platelet activity may be associated with mortality after intracerebral hemorrhage (ICH). We tested the hypothesis that reduced platelet activity is associated with early ICH clot growth and worse outcomes. Methods— We prospectively identified patients with spontaneous ICH, measured platelet activity (VerifyNow-ASA, Accumetrics) on admission, and recorded antiplatelet medication use. ICH volume was calculated using computerized volumetric analysis. Data were analyzed with nonparametric statistics and repeated measures ANOVA as appropriate. Patients were prospectively followed for functional outcomes. Data are presented as mean±SD or median [Q1 to Q3]. Results— Reduced platelet activity (≤550 aspirin reaction units [ARU]) was associated with increased ICH volume growth (P<0.05) for patients with the diagnostic CT within 12 hours. In the subset of patients not known to take aspirin, 24% had reduced platelet activity. Sixteen (24%) patients received a platelet transfusion 21.2±11.4 hours after symptom onset with an increase in platelet activity (448 [414-479] to 586 [530-639] ARU, P=0.001), but without impact on outcomes. Reduced platelet activity was associated with worse modified Rankin Scores at 3 months (P=0.02). Conclusions— Reduced platelet activity was associated with early ICH volume growth and worse functional outcome. Because platelet activity can be increased with platelet transfusion, increasing platelet activity is a potential method to reduce ICH volume growth and improve functional outcomes.

Evolution of the management of tentorial dural arteriovenous malformations

OBJECTIVETentorial dural arteriovenous malformations (DAVMs) are uncommon lesions associated with an aggressive natural history. Controversy exists regarding their optimal treatment. We present a single-institution series of tentorial DAVMs treated during a 12-year period, address the current controversies, and present the rationale for our current therapeutic strategy. METHODSTwenty-two patients with tentorial DAVMs were treated between 1988 and 2000. Treatment consisted of transarterial or transvenous embolization, surgical resection, disconnection of venous drainage, or a combination of these therapies. The clinical presentations, radiological features, treatment strategies, and results were studied. RESULTSEighteen patients (82%) presented with intracranial hemorrhage or progressive neurological deficits. Retrograde leptomeningeal venous drainage was documented in 22 cases (100%), classifying the lesions as Borden Type III. Angiographic follow-up monitoring was performed for 0 to 120 months and clinical follow-up monitoring for 1 to 120 months. Posttreatment angiography demonstrated obliteration in 22 cases (100%). Two patients experienced neurological decline after endovascular treatment and died. All of the 20 surviving patients exhibited clinical improvement; there were no episodes of rehemorrhage or new neurological deficits. Outcomes were excellent in 17 cases (77%), good in 2 cases (9%), and fair in 1 case (5%), and there were 2 deaths (9%). CONCLUSIONTentorial DAVMs are aggressive lesions that require prompt total angiographic obliteration. Disconnection of the venous drainage from the fistula may be accomplished with transarterial embolization to the venous side, transvenous embolization, or surgical disconnection of the fistula. We think that extensive nidal resections carry more risk and are unnecessary. We do not think there is a role for stereotactic radiosurgery in the treatment of these lesions.

Transradial cerebral angiography: an alternative route.

INTRODUCTION The transradial approach has been well described for arteriography of the coronary vessels. To assess the safety and success rate of the transradial approach for three-vessel or four-vessel diagnostic cerebral arteriography, we reviewed the experience at our institution and compared our complication rates with those found in the literature for transfemoral cerebral angiography and transradial coronary angiography. METHODS We reviewed the electronic medical records of 129 consecutive patients in whom 132 cerebral angiographic studies were performed by use of a transradial approach between December 1999 and June 2001. A total of 54 selective catheterizations were performed, of which 39 were of the vertebral artery, 11 of the internal carotid artery, and 4 of the external carotid artery. Records were reviewed for periprocedural and delayed complications, indications for diagnostic angiography, and requirement of conversion to a femoral approach. Records were reviewed prospectively for the first 55 procedures and retrospectively for the next 77 procedures. RESULTS The mean time to initial clinical follow-up was 1.5 months (median, 0.5 mo). The combined rate of periprocedural and delayed complications was 9%, and there were no major complications. Minor periprocedural complications included transient radial artery spasm (four patients), failure to access the brachial artery (two patients), severe pain (one patient), skin desquamation (one patient), and hematoma (one patient). There were no major complications. At the time of follow-up evaluation, these patients were without deficits related to cannulation of the radial artery. CONCLUSION The transradial approach for cerebral angiography is a safe alternative to the transfemoral route. After transradial cerebral angiography, patients require a shorter observation period and are not restricted to bed rest. As technological developments generate smaller, more pliable endovascular surgical devices, future endovascular surgery may be performed transradially.

Endovascular stenting of extracranial carotid and vertebral artery dissections: A systematic review of the literature

BACKGROUND:Carotid and vertebral artery dissections are a leading cause of stroke in young individuals. OBJECTIVE:To examine the published safety and efficacy of endovascular stenting for extracranial artery dissection. METHODS:We conducted a systematic review of the literature to identify all cases of endovascular management of extracranial carotid and vertebral artery dissections. RESULTS:For carotid dissections, our review yielded 31 published reports including 140 patients (153 vessels). Reported etiologies were traumatic (48%, n = 64), spontaneous (37%, n = 49), and iatrogenic (16%, n = 21). The technical success rate of stenting was 99%, and the procedural complication rate was 1.3%. Mean angiographic follow-up was 12.8 months (range, 2-72 months) and revealed in-stent stenosis or occlusion in 2% of patients. Mean clinical follow-up was 17.7 months (range, 1-72 months), and neurological events were seen in 1.4% of patients. For vertebral artery dissections, our review revealed 8 reports including 10 patients (12 vessels). Etiologies were traumatic (60%, n = 6), spontaneous (20%, n = 2), and iatrogenic (20%, n = 2). There was a 100% technical success rate. The mean angiographic follow-up period was 7.5 months (range, 2-12 months). No new neurological events were reported during a mean clinical follow-up period of 26.4 months (range, 3-55 months). CONCLUSION:Endovascular management of extracranial arterial dissection continues to evolve. Current experience shows that this treatment option is safe and technically feasible. Prospective randomized trials compared with medical management are needed to further elucidate the role of stenting.

The effect of vascular reconstruction device-assisted coiling on packing density, effective neck coverage, and angiographic outcome: an in vitro study.

OBJECTIVEThe objective of this study was to assess the variations in packing density, effective neck coverage, and angiographic outcome between aneurysm coiling alone and with the support of the Enterprise Vascular Reconstruction Device (VRD; Cordis Neurovascular, Inc., Miami Lakes, FL). Although the use of VRD-assisted coiling is growing due to the availability of better devices, little is known about the impact of the VRDs on the aforesaid variables. METHODSTen groups of two silicone aneurysm models each were embolized with detachable coils, one with VRD support and one without. Coil embolization ceased once the microcatheter backed out of the aneurysm or there was a risk that further packing would lead to coil herniation. Angiograms were assessed using the Raymond classification scale. Gross macroscopic images of the aneurysm neck were taken to quantify the coil neck coverage, defined as the surface area fraction of coils at the neck divided by the total neck area. Packing density was calculated. RESULTSPacking density significantly increased with VRD assistance (absolute increase, 10.5%; relative increase, 31%; P < 0.0001, paired t test). Effective neck coverage significantly increased by 9% with VRD deployment (P < 0.05, t test). Angiographically, aneurysms coiled without VRD support were more likely to have a dome remnant (P < 0.05, Fishers exact test) and coil prolapse into the parent vessel. CONCLUSIONVRD deployment improves coil neck coverage and increases packing density. These results support the hypothesis that VRD deployment to reinforce coil embolization of cerebral aneurysms may lead to more durable aneurysm obliteration.

Delayed thrombosis or stenosis following enterprise-assisted stent-coiling: Is it safe? Midterm results of the interstate collaboration of enterprise stent coiling

BACKGROUND:Stent-assisted coiling of intracranial aneurysms with self-expanding stents has widened the applicability of neuroendovascular therapies to those aneurysms previously considered “uncoilable” because of poor morphology. The Enterprise Vascular Reconstruction Device and Delivery System (Cordis) has demonstrated promising initial short-term results. However, the rates of delayed in-stent stenosis or thrombosis are not known. OBJECTIVE:To report midterm results of the Enterprise stent system. METHODS:A 10-center registry was created to provide a large volume of data on the safety and efficacy of the Enterprise stent system. Pooled data were compiled for consecutive patients undergoing Enterprise stent-assisted coiling at each institution. Available follow-up data were evaluated for the incidence of in-stent stenosis, thrombosis, and aneurysm occlusion. RESULTS:In total, 213 patients (176 females) with 219 aneurysms were treated with the Enterprise stent. One hundred ten patients had undergone delayed angiography (≥30 days from stent placement, mean follow-up 174.6 days). Forty percent of patients demonstrated total occlusion with 88% having ≥90% aneurysm occlusion. Six percent of patients had delayed (>30 days) angiographic findings, of which 3% demonstrated significant (≥50%) in-stent stenosis or occlusion. Seven delayed thrombotic events occurred (3%), along with 2 additional immediate periprocedural events. All 7 delayed events were concomitant to cessation of double-antiplatelet therapy. CONCLUSION:Midterm occlusion rates are excellent, and stenosis and thrombosis rates are comparable to other available neurovascular stents. Interruption of antiplatelet therapy appears to be a factor in those developing delayed stenosis or thrombosis.

Unruptured intracranial aneurysms and the assessment of rupture risk based on anatomical and morphological factors: sifting through the sands of data

Aneurysmal subarachnoid hemorrhage continues to have high rates of morbidity and mortality for patients despite optimal medical and surgical management. Due to the fact that aneurysmal rupture can be such a catastrophic event, preventive treatment is desirable for high-risk lesions. Given the variability of the literature evaluating unruptured aneurysms regarding basic patient population, clinical practice, and aneurysm characteristics studied, such as size, location, aspect ratio, relationship to the surrounding vasculature, and the aneurysm hemodynamics, a meta-analysis is nearly impossible to perform. This review will instead focus on the various anatomical and morphological characteristics of aneurysms reported in the literature with an attempt to draw broad inferences and serve to highlight pressing questions for the future in our continued effort to improve clinical management of unruptured intracranial aneurysms.

Brainstem cavernous malformations.

BRAINSTEM CAVERNOUS MALFORMATIONS (CMs) continue to present a considerable source of controversy in the neurosurgical community, with an accumulating volume of literature detailing their natural history and their surgical and radiosurgical management. As part of a systematic review of the literature, 12 natural history studies, 52 surgical series, and 14 radiosurgical series were tabulated. Annual bleeding rates for brainstem CMs ranged from 2.3% to 4.1% in natural history studies and from 2.68% to 6.8% in surgical series before intervention. Rebleed rates as high as 21.5% in natural history studies and greater than once per year in surgical series were reported. A total of 684 of 745 CMs (92%) were documented as completely resected in 46 series that provided specific information on resection rates. Early postoperative morbidity ranged from 29% to 67% in larger surgical series, although it was often transient. Thirty of 61 partially resected lesions rebled; 4 of these rebleeds were fatal. Twelve additional patients died from surgically related causes for a combined postoperative rebleeding and surgically related mortality rate of 1.9%. Across 45 series (683 patients), 85% of patients were reported as the same or improved, 14% were worse, and 1.9% died from surgically related causes at long-term follow-up. Patients with anterolateral pontine lesions generally appeared to have a better functional recovery, whereas those requiring excision via the floor of the fourth ventricle had relatively worse long-term outcomes. Radiosurgical series demonstrated conflicting data; some reported a statistically significant decrease in CM rebleeding rates after 2 years, whereas others did not, partially related to dosimetry. Postradiosurgical morbidity was nonetheless significantly greater for CMs than for arteriovenous malformations.

Chemical meningitis after cerebral aneurysm treatment using two second-generation aneurysm coils: Report of two cases

OBJECTIVE AND IMPORTANCE Dolichoectatic vertebrobasilar artery aneurysms are often extremely difficult, if not impossible, to treat with microneurosurgical clip reconstruction. As such, a Hunterian strategy via vertebral or basilar artery sacrifice is often used. We have encountered a patient in whom deliberate bilateral vertebral artery sacrifice was insufficient to avoid progressive expansion of a giant dolichoectatic vertebrobasilar artery aneurysm. On the basis of a review of the literature, we are unaware of another reported case. CLINICAL PRESENTATION A 60-year-old man presented with signs and symptoms of brainstem compression from a large fusiform aneurysm involving the distal dominant vertebral and proximal basilar arteries. Results of angiographic evaluation were highly characteristic of underlying dolichoectasia. INTERVENTION The patient was treated initially with staged bilateral vertebral artery occlusion and adjunctive posterior circulation revascularization. After this therapy failed, he underwent a trapping procedure and aneurysm deflation. CONCLUSION Unclippable aneurysms of the vertebrobasilar system are formidable lesions. They are not uniformly treatable by direct surgical reconstruction, and their growth is not consistently stabilized by the implementation of a complete Hunterian strategy. Future developments related to the use of endovascular stent technology may offer a more successful treatment approach for patients with these complex cerebrovascular lesions.OBJECTIVE AND IMPORTANCE: In the quest for effective and durable endovascular aneurysm treatment, second-generation aneurysm coils endeavor to increase the biological healing response to the implanted material. We report two cases of large cerebral aneurysms treated concurrently with both available second-generation aneurysm coils and the subsequent development of symptomatic nonbacterial meningitis. CLINICAL PRESENTATION: Two previously healthy patients underwent endovascular treatment for large (≥2 cm) cerebral aneurysms. Both aneurysms were treated using multiple Hydrogel coils (MicroVention, Inc., Aliso Viejo, CA) and Matrix coils (Boston Scientific/Target, Fremont, CA). Careful aseptic technique was observed throughout each procedure, and prophylactic intravenous antibiotics were administered during the perioperative period to both patients. Treatment proceeded uneventfully in both cases with excellent aneurysm occlusion and no immediate postoperative neurological deficits. INTERVENTION: In both cases, the patients were discharged from hospital but quickly were readmitted with stigmata of meningitis. Imaging demonstrated durable occlusion of the aneurysms in both patients and also abnormalities indicative of perianeurysmal and diffuse intracranial inflammatory response. Complete septic workup failed to identify an organism in either patient. Both patients responded to treatment with corticosteroid medication used to modulate the inflammatory response induced by the coil implants. CONCLUSION: Second-generation aneurysm coils were developed to promote more durable occlusion of cerebral aneurysms by promoting more complete volumetric aneurysm occlusion or by eliciting a more prolific inflammatory response. The concurrent use of Hydrogel and Matrix coil systems in large aneurysms may cause an exuberant inflammatory response with both local and systemic manifestations. Although vigilant evaluation and treatment for presumptive bacterial meningitis is required in all such cases, patients respond to immunomodulatory therapy with corticosteroids. More information to understand better the interaction of Hydrogel and Matrix coils is needed.