Endovascular and microsurgical management of blister aneurysms: a multi-centre review.

Blister aneurysms (BA) are high-risk cerebrovascular lesions accounting for 1% of intracranial aneurysms. The defective vessel wall and broad-based neck make this clinical entity difficult to treat, with high rates of re-rupture and mortality in patients presenting with acute subarachnoid haemorrhage. Blister aneurysms pose substantial challenges for both endovascular and microsurgical management. The objective of this study is to evaluate endovascular and microsurgical outcomes in intracranial blister aneurysm management across two tertiary hospitals. A review of two tertiary hospitals with a systematic imaging database search for term of "blister" in modalities from January 2010 to October 2022 was conducted. Operation reports were screened for the 5-year period since cerebral angiogram reports transitioned to surgical database. Identified reports were screened and reviewed for confirmed diagnosis by consultant neuroradiologist. A total of 21 cases of blister aneurysms managed at respective facilities were included. Sixteen cases (76%) were managed endovascularly. Four cases (19%) were managed surgically-2 with primary clipping, and 2 wrap and clipping. One case was managed conservatively (5%). Clinical outcomes were discharge disposition, aneurysm exclusion and post-operative complications. BAs have challenging considerations with high mortality and morbidity. Endovascular treatment offers a less invasive modality with lower rates of intraoperative rupture and morbidity. Mortality rates and patients discharged home were comparable. Commencement of dual anti-platelet therapy was safe in patients with flow diversion stents despite sub-arachnoid blood volume. Management of blister aneurysms is complex. Endovascular treatment shows promise for acute management but careful collaborative consideration of antithrombotic regime and requirement for further surgery should be considered.

Patient functional outcomes and quality of life after surgery for unruptured brain arteriovenous malformation.

BACKGROUND: Studies have questioned the effectiveness of surgery for the management of unruptured brain arteriovenous malformation (ubAVM). Few studies have examined functional outcomes and quality of life (QOL) prior and 12 months after surgical repair of ubAVM. OBJECTIVE: This study examined the effectiveness of surgical management of ubAVM by measuring patients' perceived QOL and their ability to perform everyday activities. METHODS: Between 2011 and 2016, patients diagnosed with an unbAVM were assessed using the Quality Metric Short Form 36 (SF36), the DriveSafe component of the off-road driver screening tool DriveSafeDriveAware (DSDA), the modified Barthel Index (mBI) and the modified Rankin Scale (mRS). Reassessments were conducted at the 6-week post-operative follow-up for surgical patients and at 12-month follow-up for surgical and conservatively managed patients. RESULTS: Forty-five patients enrolled in the study, of which 35 (78%) had their ubAVM surgically treated. Patients undergoing surgery had a significantly lower ubAVM Spetzler-Ponce Class (SPC). There was no significant difference 12 months after presentation in function or QOL for either the conservative or surgical group. The surgical group had significantly higher QOL of life scores from pre-surgery to 12 months post-surgery (PCS p < 0.01; MCS p = 0.02). Higher SP grade ubAVM was significantly related to poorer function in the surgical group (SP C compared with SP A; p = 0.04, mean difference - 12.4, 95%CI - 24.3 to - 0.4). CONCLUSION: Function and QOL are not diminished after surgical treatment of low Spetzler-Ponce Class unruptured brain arteriovenous malformations. QOL is higher 12 months after surgery for ubAVM than for those who do not have treatment for their ubAVM.

De novo brain arteriovenous malformation after tumor resection: case report and literature review.

The congenital origin of brain arteriovenous malformations (bAVMs) has been increasingly challenged by reports of de novo bAVMs in patients previously confirmed to have no vascular malformation. We describe the oldest patient reported in the English language literature harboring a de novo bAVM. An uneventful frontal convexity meningioma resection was performed for a 60-year-old woman, and at 67 years of age, a bAVM was detected by MRI and confirmed by digital subtraction angiography at the site of the previous meningioma resection. This case adds to the growing literature that the etiology of bAVMs is most likely multifactorial.

Quality of life and disability 12 months after surgery vs. conservative management for unruptured brain arteriovenous malformations: Scottish population-based and Australian hospital-based studies.

BACKGROUND: Few data are available on disability and quality of life (QOL) after surgery versus conservative management for unruptured brain arteriovenous malformations (uAVMs). OBJECTIVE: The aim of this study was to test the hypothesis that QOL and disability are worse after surgery ± preoperative embolisation for uAVM compared with conservative management. METHODS: We included consecutive patients diagnosed with uAVM from a prospective population-based study in Scotland (1999-2003; 2006-2010) and a prospective hospital-based series in Australia (2011-2015). We assessed outcomes on the modified Rankin Scale (mRS) and the Short Form (SF)-36 at ~ 12 months after surgery or conservative treatment and compared these groups using continuous ordinal regression in the two cohorts separately. RESULTS: Surgery was performed for 29% of all uAVM cases diagnosed in Scotland and 84% of all uAVM referred in Australia. There was no statistically significant difference between surgery and conservative management at 12 months among 79 patients in Scotland (mean SF-36 Physical Component Score (PCS) 39 [SD 14] vs. 39 [SD 13]; mean SF-36 Mental Component Score (MCS) 38 [SD 14] vs. 39 [SD 14]; mRS > 1, 24 vs. 9%), nor among 37 patients in Australia (PCS 51 [SD 10] vs. 49 [SD 6]; MCS 48 [SD 12] vs. 49 [SD 10]; mRS > 1, 19 vs. 30%). In the Australian series, there was no statistically significant change in the MCS and PCS between baseline before surgery or conservative management and 12 months. CONCLUSIONS: We did not find a statistically significant difference between surgery ± preoperative embolisation and conservative management in disability or QOL at 12 months.

Critical review of brain AVM surgery, surgical results and natural history in 2017.

BACKGROUND: An understanding of the present standing of surgery, surgical results and the role in altering the future morbidity and mortality of untreated brain arteriovenous malformations (bAVMs) is appropriate considering the myriad alternative management pathways (including radiosurgery, embolization or some combination of treatments), varying risks and selection biases that have contributed to confusion regarding management. The purpose of this review is to clarify the link between the incidence of adverse outcomes that are reported from a management pathway of either surgery or no intervention with the projected risks of surgery or no intervention. METHODS: A critical review of the literature was performed on the outcomes of surgery and non-intervention for bAVM. An analysis of the biases and how these may have influenced the outcomes was included to attempt to identify reasonable estimates of risks. RESULTS: In the absence of treatment, the cumulative risk of future hemorrhage is approximately 16% and 29% at 10 and 20 years after diagnosis of bAVM without hemorrhage and 35% and 45% at 10 and 20 years when presenting with hemorrhage (annualized, this risk would be approximately 1.8% for unruptured bAVMs and 4.7% for 8 years for bAVMs presenting with hemorrhage followed by the unruptured bAVM rate). The cumulative outcome of these hemorrhages depends upon whether the patient remains untreated and is allowed to have a further hemorrhage or is treated at this time. Overall, approximately 42% will develop a new permanent neurological deficit or death from a hemorrhagic event. The presence of an associated proximal intracranial aneurysm (APIA) and restriction of venous outflow may increase the risk for subsequent hemorrhage. Other risks for increased risk of hemorrhage (age, pregnancy, female) were examined, and their purported association with hemorrhage is difficult to support. Both the Spetzler-Martin grading system (and its compaction into the Spetzler-Ponce tiers) and Lawton-Young supplementary grading system are excellent in predicting the risk of surgery. The 8-year risk of unfavorable outcome from surgery (complication leading to a permanent new neurological deficit with a modified Rankin Scale score of greater than one, residual bAVM or recurrence) is dependent on bAVM size, the presence of deep venous drainage (DVD) and location in critical brain (eloquent location). For patients with bAVMs who have neither a DVD nor eloquent location, the 8-year risk for an unfavorable outcome increases with size (increasing from 1 cm to 6 cm) from 1% to 9%. For patients with bAVM who have either a DVD or eloquent location (but not both), the 8-year risk for an unfavorable outcome increases with the size (increasing from 1 cm to 6 cm) from 4% to 35%. For patients with bAVM who have both a DVD and eloquent location, the 8-year risk for unfavorable outcome increases with size (increasing from 1 cm to 3 cm) from 12% to 38%. CONCLUSION: Patients with a Spetzler-Ponce A bAVM expecting a good quality of life for the next 8 years are likely to do better with surgery in expert centers than remaining untreated. Ongoing research is urgently required on the outcome of management pathways for bAVM.

Institution of sustained endovascular treatment prior to clinical deterioration in patients with severe angiographic vasospasm: A retrospective observational study of clinico-radiological outcomes.

UNLABELLED: Severe angiographic vasospasm (aVSP) is a risk factor for infarction following subarachnoid haemorrhage and infarction is strongly associated with poor outcome. We present the clinico-radiological results of cohort with severe aVSP who underwent a program of angiographic surveillance and sustained endovascular treatment using multiple verapamil infusions and/or transluminal balloon angioplasty (TBA). METHODS: This was a dual-centre retrospective observational study. Angiographic screening for vasospasm was undertaken at days 5-7 post-ictus. Treatment was instituted principally on the basis of radiographic findings. The rate of infarction was evaluated on follow-up CT. Clinical outcome was assessed using the modified Rankin Scale (mRS). RESULTS: Fifty-seven WFNS grades 1-5 patients were studied. The mean number of procedures/patient was 6, range 2-13. Mean verapamil dose administered to the ICA was 14 mg and VA was 12 mg. Thirty-one patients underwent TBA (52.6%). The rate of proximal vessel infarction was 3/45 (6.7%) for patients presenting <72 hours. Rates of favourable outcome (mRS 0-2) were 16/19 (84.2%) for WFNS grades 1-2, 12/19 (63.2%) for grades 3-4 and 5/19 (26.3%) for grade 5 patients. Delayed presentation >72 hours was the only factor on multivariate analysis to significantly predict aVSP-infarction [OR19.3 (3.2-116.6) P=0.0012]. Large aVSP-infarction [OR19.0 (1.7-216.4) 0.0179] and poor WFNS grade [OR 6.6 (1.3-33.9) P = 0.0233] were significant predictors of poor outcome on multivariate analysis. CONCLUSION: This approach may result in low rates of aVSP-infarction and encouraging rates of favourable outcome when compared to literature benchmarks. Delayed presentation, however, predicts infarction and large infarct and poor initial grade significantly influence functional outcome.

Role of surgery in the management of brain arteriovenous malformations: prospective cohort study.

BACKGROUND AND PURPOSE: Management of brain arteriovenous malformation (bAVM) is controversial. We have analyzed the largest surgical bAVM cohort for outcome. METHODS: Both operated and nonoperated cases were included for analysis. A total of 779 patients with bAVMs were consecutively enrolled between 1989 and 2014. Initial management recommendations were recorded before commencement of treatment. Surgical outcome was prospectively recorded and outcomes assigned at the last follow-up visit using modified Rankin Scale. First, a sensitivity analyses was performed to select a subset of the entire cohort for which the results of surgery could be generalized. Second, from this subset, variables were analyzed for risk of deficit or near miss (intraoperative hemorrhage requiring blood transfusion of ≥2.5 L, hemorrhage in resection bed requiring reoperation, and hemorrhage associated with either digital subtraction angiography or embolization). RESULTS: A total of 7.7% of patients with Spetzler-Ponce classes A and B bAVM had an adverse outcome from surgery leading to a modified Rankin Scale >1. Sensitivity analyses that demonstrated outcome results were not subject to selection bias for Spetzler-Ponce classes A and B bAVMs. Risk factors for adverse outcomes from surgery for these bAVMs include size, presence of deep venous drainage, and eloquent location. Preoperative embolization did not affect the risk of perioperative hemorrhage. CONCLUSIONS: Most of the ruptured and unruptured low and middle-grade bAVMs (Spetzler-Ponce A and B) can be surgically treated with a low risk of permanent morbidity and a high likelihood of preventing future hemorrhage. Our results do not apply to Spetzler-Ponce C bAVMs.

Staged Common and External Carotid Artery Stenting Followed by Superficial Temporal Artery to Middle Cerebral Artery Bypass.

Superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery for internal carotid artery (ICA) occlusive disease necessarily requires sufficient external carotid artery (ECA) blood flow. Surgical bypass is therefore precluded if there is common carotid artery (CCA) occlusion. Here we present two such cases: one patient had a CCA occlusion and the other had an ICA occlusion and ECA stenosis. Both had failed medical management, and were therefore treated with angioplasty and stenting of the ECA, followed by STA-MCA bypass. We describe the clinical and radiologic outcomes of these cases, and remark on the potential pitfalls associated with this novel approach.

Significant venous flow alterations following brain arteriovenous malformation Surgery: Assessment by transcranial colour duplex.

Brain arteriovenous malformation (bAVM) resection imposes several post-operative clinical challenges including intracranial haemorrhage (ICH). Daily non-invasive monitoring of haemodynamic measurements may be useful in predicting post-operative ICH. This prospective study used transcranial colour duplex (TCCD) and central aortic pressure (CAP) measurements to evaluate 15 bAVM patients pre-operatively and daily ≤ 14 days post-operatively. TCCD measurements of middle cerebral artery and veins included peak systolic (PSV), end diastolic (EDV), and pulsatility indices (PI). Parameters were compared with 7 craniotomy patients (non-bAVM craniotomy/surgical group). Normal reference values included 20 healthy volunteers. Significant middle cerebral vein MCV changes in bAVM patients occurred; Maximal PSV was significantly higher (median 47 cm/s) compared to non-bAVM craniotomy/surgical controls (median 17 cm/s, p = 0.0123); maximal PI was significantly higher (median 0.99, p = 0.005) compared to the non-bAVM craniotomy/surgical controls (median 0.49). In 8 of 15 patients, increased MCV velocity and pulsatility "stabilised" within 14 days post-operatively. Mean number of days for the 8 patients to reach stable state was 5.9 days, (range 0-9 days). To our knowledge, this is the first imaging study demonstrating significant venous changes post bAVM resection. Significant increased venous flow occurs in pial veins bilaterally. Increased pressure of venous flow is evidenced by a significant increase in diameter and pulsatility. Subsequently, haemorrhagic complications may be due distal constriction of the pial veins causing venous hypertension. The cause of the dilated vascular bed is unknown.

Medical treatment of polymeric cerebral granulomatous reactions following endovascular procedures.

BACKGROUND: Endovascular procedures are standard of care for an increasing range of cerebrovascular diseases. Many endovascular devices contain plastic and are coated with a hydrophilic polymer which has been rarely described to embolize, resulting in distal granulomatous inflammatory lesions within the vascular territory. METHODS: We reviewed three cases of cerebral granulomatous reactions that occurred after endovascular intervention for internal carotid aneurysms. The patient procedure details, presentation, relevant investigations, and treatment course are described. We also provide a literature review on endovascular granulomatous reactions. RESULTS: These three cases represent the largest biopsy proven series of cerebral granulomatosis following endovascular intervention. We highlight the variable clinical presentation, with two of the three cases having an unusually delayed onset of up to 4 years following the intervention. We show the characteristic histological findings of granulomatous lesions with foreign body material consistent with a type IV reaction, radiological abnormalities of enhancing lesions within the vascular territory of the intervention, and the requirement of prolonged immunosuppression for maintenance of clinical remission, with two of the three patients requiring a corticosteroid sparing agent. In comparison with the available literature, in addition to hydrophilic gel polymer, we discuss that plastic from the lining of the envoy catheter may be a source of embolic material. We also discuss the recommendations of the Food and Drug Administration and the implementation of novel biomaterials for the prevention of these reactions in the future. CONCLUSIONS: There is a need for increased awareness of this severe complication of cerebral endovascular procedures and further longitudinal studies of its prevalence, optimal management and preventative measures.

Do prophylactic steroids prevent chemical meningitis in surgery for epidermoid cysts? Case report and literature review.

BACKGROUND: Cranial and spinal epidermoid cysts (ECs) are rare and surgical resection can be complicated by chemical meningitis. Here, we treated a patient undergoing surgical resection of an intramedullary spinal EC with prophylactic steroids to help prevent postoperative chemical meningitis. Notably, we found a paucity of evidence regarding the efficacy of steroids used for this purpose. CASE DESCRIPTION: A 44-year-old male presented with a rare intramedullary thoracic EC. He was given oral dexamethasone postoperatively and did not subsequently develop chemical meningitis. Here, we reviewed the current literature regarding the efficacy of steroid use for this purpose, utilizing multiple electronic databases (Ovid MEDLINE, Ovid EMBASE, and Scopus). We found only three studies (one case report, one case series, and a randomized controlled trial), that involved patients who received steroids. Of the 24 patients given prophylactic steroids, none developed fever or meningismus. One patient received 8 days of oral dexamethasone. Eleven patients received intraoperative hydrocortisone irrigation alone, while final 12 patients received intraoperative hydrocortisone irrigation plus a 3 week postoperative tapering course of oral steroids. Notably, all of the nine patients who did not receive any steroids developed postoperative fever, with 78% demonstrating meningismus. CONCLUSION: Here is level II evidence that establishes the efficacy of prophylactic steroids utilized in patients undergoing surgery for ECs to prevent postoperative chemical meningitis. Nevertheless, there is still no current consensus regarding either the type of steroid utilized, or the route of administration.

Kinked Perforator Due to Clipping of Parent Vessel Aneurysm: Technical Note and Lessons Learned.

BACKGROUND: Adverse outcomes after aneurysm clipping can be potentially reversible, when managed appropriately. METHODS: This is a case report describing kinking of a perforator due to clipping of parent vessel aneurysm. RESULTS: Complete recovery of a high-grade motor deficit was achieved after instant reintervention with application of smaller clips in combination with gelfoam soaked in papaverine. CONCLUSION: Use of evoked potentials and intraoperative digital subtraction angiography are recommended and may help in preclinical diagnosis. Knowledge of delayed perforator kinking as a complication may lead to a more rapid diagnosis and management.

Results of Surgery for Low-Grade Brain Arteriovenous Malformation Resection by Early Career Neurosurgeons: An Observational Study.

BACKGROUND: For sustainability of arteriovenous malformation (AVM) surgery, results from early career cerebrovascular neurosurgeons (ECCNs) must be acceptably safe. OBJECTIVE: To determine whether ECCNs performance of Spetzler-Ponce Class A AVM (SPC A) resection can be acceptably safe. METHODS: ECCNs completing a cerebrovascular fellowship (2004-2015) with the last author were included. Inclusion of the ECCN cases occurred if they: had a prospective database of all AVM cases since commencing independent practice; were the primary surgeon on SPC A; and had made the significant management decisions. All SPC A surgical cases from the beginning of the ECCN's independent surgical practice to a maximum of 8 yr were included. An adverse outcome was considered a complication of surgery leading to a new permanent neurological deficit with a last modified Rankin Scale score >1. A cumulative summation (Cusum) plot examined the performance of each surgery. The highest acceptable level of adverse outcomes for the Cusum was 3.3%, derived from the upper 95% confidence interval of the last author's reported series. RESULTS: Six ECCNs contributed 110 cases for analysis. The median number of SPC A cases operated by each ECCN was 16.5 (range 4-40). Preoperative embolization was performed in 5 (4.5%). The incidence of adverse outcomes was 1.8% (95% confidence interval: <0.01%-6.8%). At no point during the accumulated series did the combined cohort become unacceptable by the Cusum plot. CONCLUSION: ECCNs with appropriate training appointed to large-volume cerebrovascular centers can achieve results for surgery for SPC A that are not appreciably worse than those published from high-volume neurosurgeons.

Laminar Wall Shear Stress in Brain Arteriovenous Malformations: Systematic Review of Literature.

BACKGROUND: Laminar wall sheer stress (LWSS) modulates inflammatory activity of the endothelium and may be a contributing factor in many cerebrovascular pathologies. There is a lack of consensus whether significant differences in LWSS exist between feeding vessels in brain arteriovenous malformation (bAVM) and healthy vessels. A systematic review of LWSS research in bAVM was undertaken, including the methods used and the assumptions made in determining LWSS. METHODS: Ovid MEDLINE, EMBASE, and Scopus electronic databases were systematically searched from inception for articles calculating LWSS in bAVM cases. LWSS values were extracted for comparison between ipsilateral bAVM feeding arteries and healthy contralateral vessels or healthy normative data. RESULTS: Three retrospective cohort studies were identified, reporting on 42 adult and pediatric bAVM cases. Mean LWSS (mLWSS) in healthy vessels (contralateral vessels or normative controls) typically ranged from 1.2-2.7 Pa, while mLWSS values in untreated bAVM feeding arteries typically ranged from 1.6-3.6 Pa. All studies had mixed cohorts of ruptured and unruptured cases, obscuring the relationship between LWSS and bAVM history. CONCLUSIONS: mLWSS values in healthy arteries and bAVM feeding vessels tend to be low and overlapping. Further research of high scientific and methodologic quality is necessary to improve understanding of how LWSS hemodynamics relate to bAVM formation, rupture, and treatment.

Risk of First Hemorrhage of Brain Arteriovenous Malformations During Pregnancy: A Systematic Review of the Literature.

BACKGROUND: Recommendations on the management of brain arteriovenous malformations (bAVM) with respect to pregnancy are based upon conflicting literature. OBJECTIVE: To systematically review the reported risk and annualized rate of first intracranial hemorrhage (ICH) from bAVM during pregnancy and puerperium. METHODS: MEDLINE, EMBASE, and Scopus databases were searched for relevant articles in English published before April 2018. Studies providing a quantitative risk of ICH in bAVM during pregnancy were eligible. RESULTS: From 7 initially eligible studies, 3 studies met the criteria for providing quantitative risk of first ICH bAVM during pregnancy. Data from 47 bAVM ICH during pregnancy across 4 cohorts were extracted for analysis. Due to differences in methodology and definitions of exposure period, it was not appropriate to combine the cases. The annualized risk of first ICH during pregnancy for these 4 cohorts was 3.0% (95% confidence interval [CI]: 1.7-5.2%); 3.5% (95% CI: 2.4-4.5%); 8.6% (95% CI: 1.8-25%); and 30% (95% CI: 18-49%). Only the last result from the last cohort could be considered significantly increased in comparison with the nonpregnant period (relative rate 6.8, 95% CI: 3.6-13). The limited number of eligible studies and variability in results highlighted the need for enhanced rigor of future research. CONCLUSION: There is no conclusive evidence of an increased risk of first hemorrhage during pregnancy from bAVM. Because advice to women with bAVM may influence the management of pregnancy or bAVM with significant consequences, we believe that a retrospective multicenter, case crossover study is urgently required.

Similarities and differences in aneurysmal subarachnoid haemorrhage between eastern Finland and northern Sydney.

A significant body of literature on aneurysmal subarachnoid haemorrhage has emerged from Finland. The Finnish source from a small founding population, rather than from a wide heterogeneous source such as used for other populations, suggests the need for caution when attempting to generalise using Finnish data. This study aims to identify the differences and similarities between the aneurysmal subarachnoid haemorrhage populations of eastern Finland and northern Sydney to ascertain whether information that is derived from Finland has applicability to an Australian context. Existing aneurysmal subarachnoid haemorrhage databases of Kuopio University Hospital in eastern Finland and the Royal North Shore and Dalcross Private Hospitals in northern Sydney from 2000 to 2005 were combined and analysed. A total of 879 patients were identified. Comparisons fell into three categories: features that were similar between the two populations; those with apparent differences that may be explained by methods of data collection or referral patterns; and differences that probably represent a true difference between these populations. The differences suggest that genetic predispositions for aneurysm development may not affect the likelihood for aneurysmal rupture.

How does the participation of a resident surgeon in procedures for small intracranial aneurysms impact patient outcome?

OBJECT: In this paper the authors' goal was to evaluate whether resident neurosurgeons participating in entry-level aneurysm surgery have a negative impact on patient outcomes. METHODS: The authors searched the database for entry-level aneurysm surgeries (that is, those < or =10 mm and located in the internal carotid artery [beyond the paraclinoid segment] and middle cerebral artery) performed in 1991 through 2005. The presence or absence of an advanced resident (in his/her last 3 years of residency) was noted. The analysis was examined in 3-year quintiles. A total of 355 cases (196 with resident participation and 159 without) were evaluated. Permanent adverse outcomes were seen in 11 patients (3.1% of the total study population), all due to branch artery occlusion. The incidence of permanent adverse outcomes in the first 3 years was 10.7% and 2.4% thereafter. This difference was statistically significant (p = 0.015). There was no difference in the incidence of adverse outcomes when comparing surgery performed with and without participation of an advanced resident. CONCLUSIONS: In this study the authors have demonstrated a learning curve in this series of patients. This study also suggests that involving residents in the repair of small unruptured aneurysms will not compromise patient care. In addition, patients can be informed that the team approach to their surgery is at least as good as having the experienced surgeon performing all aspects of the surgery.

Deliberate employment of postoperative hypotension for brain arteriovenous malformation surgery and the incidence of delayed postoperative hemorrhage: a prospective cohort study.

OBJECTIVE The aim of this study was to examine the impact of deliberate employment of postoperative hypotension on delayed postoperative hemorrhage (DPH) for all Spetzler-Ponce Class (SPC) C brain arteriovenous malformations (bAVMs) and SPC B bAVMs ≥ 3.5 cm in diameter (SPC B 3.5+). METHODS A protocol of deliberate employment of postoperative hypotension was introduced in June 1997 for all SPC C and SPC B 3.5+ bAVMs. The aim was to achieve a maximum mean arterial blood pressure (BP) ≤ 70 mm Hg (with cerebral perfusion pressure > 50 mm Hg) for a minimum of 7 days after resection of bAVMs (BP protocol). The authors compared patients who experienced DPH (defined as brain hemorrhage into the resection bed that resulted in a new neurological deficit or that resulted in reoperation during the hospitalization for microsurgical bAVM resection) between 2 periods (prior to adopting the BP protocol and after introduction of the BP protocol) and 4 bAVM categories (SPC A, SPC B 3.5- [that is, SPC B < 3.5 cm maximum diameter], SPC B 3.5+, and SPC C). Patients excluded from treatment by the BP protocol were managed in the intensive care unit to avoid moderate hypertensive episodes. The pooled cases of all bAVM treated by surgery were analyzed to identify characteristics associated with the risk of DPH. These identified characteristics were then examined by multiple logistic regression analysis in both SPC B 3.5+ and SPC C cases. RESULTS From a cohort of 641 bAVMs treated by microsurgery, 32 patients with DPH were identified. Of those, 66% (95% CI 48-80) had a permanent new neurological deficit with a modified Rankin Scale score of 2-6. This included a mortality rate of 13% (95% CI 4.4-29). The BP protocol was used to treat 162 patients with either SPC B 3.5+ or SPC C. For SPC B 3.5+, there was no significant reduction in DPH with the introduction of the BP protocol (p = 0.77). For SPC C, there was a significant (p = 0.035) reduction of DPH from 29% (95% CI 13%-53%) to 8.2% (95% CI 3.2%-18%) associated with the introduction of the BP protocol. Multiple logistic regression analysis found that the absence of the BP protocol (p = 0.011, odds ratio 7.5, 95% CI 1.6-36) remained significant for the development of DPH in patients with SPC C bAVMs. CONCLUSIONS Treating patients with SPC C bAVMs with a protocol that lowers BP immediately after resection seems to reduce the risk of DPH. For SPC A and SPC B 3.5- bAVMs, there is unlikely to be a need to do more than avoid postoperative hypertension. For SPC B 3.5+ bAVMs, a larger number of patients would be required to test the absence of benefit of the BP protocol.

Complication-Effectiveness Analysis for Brain Arteriovenous Malformation Surgery: A Prospective Cohort Study.

BACKGROUND: Intervention for brain arteriovenous malformations (bAVMs) should aim at treatment that is safe and effective. OBJECTIVE: To analyze a prospective database to derive the probability of neurological deficit and adjust this risk for effectively treated bAVMs (complication-effectiveness analysis [CEA]). METHODS: First, we calculated the percentage of surgical complications leading to a modified Rankin Scale >1 at 12 months after surgery for each Spetzler-Ponce class (SPC). Second, we performed a sensitivity analysis of these results by including bAVMs not undergoing surgery, to correct for bias. Third, we established the long-term cumulative incidence of freedom from recurrence from Kaplan-Meier analysis. Finally, we combined the results to calculate the risk of surgery per effective treatment in a complication-effectiveness analysis. RESULTS: Seven hundred seventy-nine patients underwent 641 microsurgical resections. Complications of surgery leading to a modified Rankin Scale >1 at 12 months occurred in 1.4% (95% confidence interval [CI]: 0.5-3.3), 20% (95% CI: 15-26), and 41% (95% CI: 30-52) of SPC A, SPC B, and SPC C, respectively. The cumulative 9-year freedom from recurrence was 97% for SPC A and 92% for other bAVMs. The 9-year CEA risk was 1.4% (credible range: 0.5%-3.4%) for SPC A, 22% to 24% (credible range: 16%-31%) for SPC B, and 45% to 63% (credible range: 33%-73%) for SPC C bAVM. CONCLUSION: CEA presents the treatment outcome in the context of efficacy and provides a basis for comparing outcomes from techniques with different times to elimination of the bAVM. ABBREVIATIONS: bAVM, brain arteriovenous malformationCEA, complication-effectiveness analysisCI, confidence intervalCTA, computerized tomographic angiographyDSA, digital subtraction angiographyMRA, magnetic resonance angiographymRS, modified Rankin ScaleSMG, Spetzler-Martin gradeSPC, Spetzler-Ponce class.

Complication-Effectiveness Analysis for Unruptured Intracranial Aneurysm Surgery: A Prospective Cohort Study.

BACKGROUND: The aim of intervention for unruptured intracranial aneurysms (UIAs) is safe, effective treatment. OBJECTIVE: To analyze a prospective database for variables influencing the risk of surgery to produce a risk model adjusting this risk for effectively treated aneurysms. METHODS: First, we identified variables to create a model from multiple logistic regression for complications of surgery leading to a 12-month modified Rankin Scale score >1. Second, we established the long-term cumulative incidence of freedom from retreatment or rupture (treated aneurysm) from Kaplan-Meier analysis. Third, we combined these analyses to establish a model of risk of surgery per effective treatment. RESULTS: One thousand twelve patients with 1440 UIA underwent 1080 craniotomies. We found that 10.1% (95% confidence interval [CI], 8.4-12.0) of craniotomies resulted in a complication leading to a modified Rankin Scale score >1 at 12 months. Logistic regression found age (odds ratio, 1.04; 95% CI, 1.02-1.06), size (odds ratio, 1.12; 95% CI, 1.09-1.15), and posterior circulation location (odds ratio, 2.95; 95% CI, 1.82-4.78) to be significant. Cumulative 10-year risk of retreatment or rupture was 3.0% (95% CI, 1.3-7.0). The complication-effectiveness model was derived by dividing the complication risk by the 10-year cumulative freedom from retreatment or rupture proportion. Risk per effective treatment ranged from 1% for a 5-mm anterior circulation UIA in a 20-year-old patient to 70% for a giant posterior circulation UIA in a 70-year-old patient. CONCLUSION: Complication-effectiveness analyses increase the information available with regard to outcome for the management of UIAs.