Janneke van Beijnum

Treatment of Brain Arteriovenous Malformations: A Systematic Review and Meta-analysis

CONTEXT Outcomes following treatment of brain arteriovenous malformations (AVMs) with microsurgery, embolization, stereotactic radiosurgery (SRS), or combinations vary greatly between studies. OBJECTIVES To assess rates of case fatality, long-term risk of hemorrhage, complications, and successful obliteration of brain AVMs after interventional treatment and to assess determinants of these outcomes. DATA SOURCES We searched PubMed and EMBASE to March 1, 2011, and hand-searched 6 journals from January 2000 until March 2011. STUDY SELECTION AND DATA EXTRACTION We identified studies fulfilling predefined inclusion criteria. We used Poisson regression analyses to explore associations of patient and study characteristics with case fatality, complications, long-term risk of hemorrhage, and successful brain AVM obliteration. DATA SYNTHESIS We identified 137 observational studies including 142 cohorts, totaling 13,698 patients and 46,314 patient-years of follow-up. Case fatality was 0.68 (95% CI, 0.61-0.76) per 100 person-years overall, 1.1 (95% CI, 0.87-1.3; n = 2549) after microsurgery, 0.50 (95% CI, 0.43-0.58; n = 9436) after SRS, and 0.96 (95% CI, 0.67-1.4; n = 1019) after embolization. Intracranial hemorrhage rates were 1.4 (95% CI, 1.3-1.5) per 100 person-years overall, 0.18 (95% CI, 0.10-0.30) after microsurgery, 1.7 (95% CI, 1.5-1.8) after SRS, and 1.7 (95% CI, 1.3-2.3) after embolization. More recent studies were associated with lower case-fatality rates (rate ratio [RR], 0.972; 95% CI, 0.955-0.989) but increased rates of hemorrhage (RR, 1.02; 95% CI, 1.00-1.03). Male sex (RR, 0.964; 95% CI, 0.945-0.984), small brain AVMs (RR, 0.988; 95% CI, 0.981-0.995), and those with strictly deep venous drainage (RR, 0.975; 95% CI, 0.960-0.990) were associated with lower case fatality. Lower hemorrhage rates were associated with male sex (RR, 0.976, 95% CI, 0.964-0.988), small brain AVMs (RR, 0.988, 95% CI, 0.980-0.996), and brain AVMs with deep venous drainage (0.982, 95% CI, 0.969-0.996). Complications leading to permanent neurological deficits or death occurred in a median 7.4% (range, 0%-40%) of patients after microsurgery, 5.1% (range, 0%-21%) after SRS, and 6.6% (range, 0%-28%) after embolization. Successful brain AVM obliteration was achieved in 96% (range, 0%-100%) of patients after microsurgery, 38% (range, 0%-75%) after SRS, and 13% (range, 0%-94%) after embolization. CONCLUSIONS Although case fatality after treatment has decreased over time, treatment of brain AVM remains associated with considerable risks and incomplete efficacy. Randomized controlled trials comparing different treatment modalities appear justified.

Outcome After Conservative Management or Intervention for Unruptured Brain Arteriovenous Malformations

IMPORTANCE Whether conservative management is superior to interventional treatment for unruptured brain arteriovenous malformations (bAVMs) is uncertain because of the shortage of long-term comparative data. OBJECTIVE To compare the long-term outcomes of conservative management vs intervention for unruptured bAVM. DESIGN, SETTING, AND POPULATION Population-based inception cohort study of 204 residents of Scotland aged 16 years or older who were first diagnosed as having an unruptured bAVM during 1999-2003 or 2006-2010 and followed up prospectively for 12 years. EXPOSURES Conservative management (no intervention) vs intervention (any endovascular embolization, neurosurgical excision, or stereotactic radiosurgery alone or in combination). MAIN OUTCOMES AND MEASURES Cox regression analyses, with multivariable adjustment for prognostic factors and baseline imbalances if hazards were proportional, to compare rates of the primary outcome (death or sustained morbidity of any cause by Oxford Handicap Scale [OHS] score ≥2 for ≥2 successive years [0 = no symptoms and 6 = death]) and the secondary outcome (nonfatal symptomatic stroke or death due to bAVM, associated arterial aneurysm, or intervention). RESULTS Of 204 patients, 103 underwent intervention. Those who underwent intervention were younger, more likely to have presented with seizure, and less likely to have large bAVMs than patients managed conservatively. During a median follow-up of 6.9 years (94% completeness), the rate of progression to the primary outcome was lower with conservative management during the first 4 years of follow-up (36 vs 39 events; 9.5 vs 9.8 per 100 person-years; adjusted hazard ratio, 0.59; 95% CI, 0.35-0.99), but rates were similar thereafter. The rate of the secondary outcome was lower with conservative management during 12 years of follow-up (14 vs 38 events; 1.6 vs 3.3 per 100 person-years; adjusted hazard ratio, 0.37; 95% CI, 0.19-0.72). CONCLUSIONS AND RELEVANCE Among patients aged 16 years or older diagnosed as having unruptured bAVM, use of conservative management compared with intervention was associated with better clinical outcomes for up to 12 years. Longer follow-up is required to understand whether this association persists.

Outcome after spontaneous and arteriovenous malformation-related intracerebral haemorrhage: population-based studies

Spontaneous (non-traumatic) intracerebral haemorrhage (ICH) has a high case-fatality and leaves many survivors disabled. Clinical characteristics and outcome seem to vary according to the cause of ICH, but population-based comparisons are scarce. We studied two prospective, population-based cohorts to determine differences in outcome [case-fatality and modified Rankin Scale (mRS)] after incident ICH due to brain arteriovenous malformations (AVM) [Scottish Intracranial Vascular Malformation Study (SIVMS), n = 90] and spontaneous ICH [Oxford Vascular Study (OXVASC), n = 60]. Patients with AVM-ICH were younger, had lower pre-stroke and admission blood pressure (BP), higher admission Glasgow Coma Scale (GCS) and were more likely to have an ICH in a lobar location than patients with spontaneous ICH (sICH). Case fatality throughout 2-year follow-up was greater following sICH than AVM-ICH [34/56 (61%) versus 11/90 (12%) at 1 year, odds ratio (OR) 11 (95% Confidence Interval (CI) 5-25)], as was death or dependence (mRS >or= 3) [40/48 (83%) versus 26/65 (40%) at 1 year, OR 8 (3-19)]. Differences in outcome persisted following stratification by age and sensitivity analyses. In multivariable analyses of 1 year outcome, independent predictors of death were sICH (OR 21, 4-104) and increasing ICH volume (OR 1.03, 1.01-1.05), and independent predictors of death or dependence were sICH (OR 11, 2-62) and GCS on admission (OR 0.79, 0.67-0.93). Outcome after AVM-ICH is better than after sICH, independent of patient age and other known predictors of ICH outcome.

Outcome after interventional or conservative management of unruptured brain arteriovenous malformations: a prospective, population-based cohort study

BACKGROUND The decision about whether to treat an unruptured brain arteriovenous malformation (AVM) depends on a comparison of the estimated lifetime risk of intracranial haemorrhage with the risks of interventional treatment. We aimed to test whether outcome differs between adults who had interventional AVM treatment and those who did not. METHODS All adults in Scotland who were first diagnosed with an unruptured AVM during 1999-2003 (n=114) entered our prospective, population-based study. We compared the baseline characteristics and 3-year outcome of adults who received interventional treatment for their AVM (n=63) with those who did not (n=51). FINDINGS At presentation, adults who were treated were younger (mean 40 vs 55 years of age, 95% CI for difference 9-20; p<0.0001), more likely to present with a seizure (odds ratio 2.4, 95% CI 1.1-5.0), and had fewer comorbidities (median 3 vs 4, p=0.03) than those who were not treated. Despite these baseline imbalances, treated and untreated groups did not differ in progression to Oxford Handicap Scale (OHS) scores of 2-6 (log-rank p=0.12) or 3-6 (log-rank p=0.98) in survival analyses. In a multivariable Cox proportional hazards analysis, the risk of poor outcome (OHS 2-6) was greater in patients who had interventional treatment than in those who did not (hazard ratio 2.5, 95% CI 1.1-6.0) and was greater in patients with a larger AVM nidus (hazard ratio 1.3, 95% CI 1.1-1.7). The treated and untreated groups did not differ in time to an OHS score of 2 or more that was sustained until the end of the third year of follow-up, or in the spectrum of dependence as measured by the OHS at 1, 2, and 3 years of follow-up. INTERPRETATION Greater AVM size and interventional treatment were associated with worse short-term functional outcome for unruptured AVMs, but the longer-term effects of intervention are unclear.

Radiological Investigation of Spontaneous Intracerebral Hemorrhage Systematic Review and Trinational Survey

Background and Purpose— It is not always clear whether, how, and when to undertake further radiological investigation of spontaneous (nontraumatic) intracerebral hemorrhage (ICH). Methods— We systematically reviewed Ovid MEDLINE and EMBASE databases for studies of the diagnostic utility of radiological investigations of the cause(s) of ICH. We sent a structured survey to neurologists, stroke specialists, neurosurgeons, and neuroradiologists in the United Kingdom, the Netherlands, and France to assess whether, how, and when they would investigate supratentorial ICH. Results— This systematic review detected 20 relevant studies (including 1933 patients), which either quantified the yield of a radiological investigation/imaging strategy (n=15) or compared 2 imaging techniques (n=5). Six hundred ninety-two (49%) physicians responded to the survey. Further investigation would have been undertaken by the following: 99% of respondents, for younger (38 to 43 years), normotensive adults with lobar or deep ICH; 76%, for older (age 72 to 83 years), normotensive adults with deep ICH; and 31%, for older adults with deep ICH and prestroke hypertension. Younger patient age was the strongest influence on the decision to further investigate ICH (odds ratio=16; 95% confidence interval, 13 to 20), followed by the absence of prestroke hypertension (odds ratio=5; 95% confidence interval, 4 to 6) and lobar ICH location (odds ratio=2; 95% confidence interval, 1 to 2). Conclusions— The paucity of studies on the diagnostic utility of imaging investigations of the cause(s) of ICH may contribute to the variation observed in when and how and which patients are investigated in current clinical practice. Studies comparing different types of diagnostic strategies are required.

Prevalence of Brain Arteriovenous Malformations in First-Degree Relatives of Patients With a Brain Arteriovenous Malformation

Background and Purpose— It is uncertain whether familial occurrence of brain arteriovenous malformations (BAVMs) represents coincidental aggregation or a shared familial risk factor. We aimed to compare the prevalence of BAVMs in first-degree relatives (FDRs) of patients with BAVM and the prevalence in the general population. Methods— We sent a postal questionnaire to 682 patients diagnosed with a BAVM in 1 of 4 university hospitals to retrieve information about the occurrence of BAVMs among their FDRs. We calculated a prevalence ratio using the BAVM prevalence among FDRs and the prevalence from a Scottish population-based study (93 per 628 788 adults). A prevalence ratio of ≥9 with a lower limit of the 95% confidence interval of 3 was considered indicative of a shared familial risk factor. Results— Informed consent was given by 460 (67%) patients, who had 2992 FDRs. We identified 3 patients with a FDR with a BAVM, yielding a prevalence ratio of 6.8 (95% CI, 2.2–21). Conclusions— The prevalence of BAVMs in FDRs of patients with a BAVM was increased but did not meet our prespecified criterion for a shared familial risk factor. In combination with the low absolute risk of a BAVM in FDRs, our results do not support screening of FDRs for BAVMs.

Patterns of Brain Arteriovenous Malformation Treatment Prospective, Population-Based Study

Background and Purpose— The extent of variation in the interventional treatment of brain arteriovenous malformations (AVMs) is unknown, so we explored patterns of treatment at 4 neuroscience centers in one European country. Methods— We included every participant with an AVM in a prospective, population-based cohort study of adults aged ≥16 years residing in Scotland at the time of AVM diagnosis in 1999 to 2003. Results— Only 11 (5%) of the 229 adults were not managed at a neuroscience center. Adults who received interventional treatment were younger (median, 43 versus 54 years), more likely to have presented with hemorrhage (OR, 2.8; 95% CI, 1.6 to 4.9), and had smaller AVMs (median nidus diameter, 2 cm versus 3 cm; P=0.003) than those who did not. Adults seen at the 4 centers only differed in AVM Spetzler-Martin grade (P=0.04). The 4 centers did not differ in the proportion of adults with AVMs who received interventional treatment (P=0.16), but they differed in the Spetzler-Martin grade of the AVMs they treated (Grades III to IV, P=0.01) and the interventional treatments used (P=0.004). The 2 largest centers differed from each other in the likelihood of surgical resection (OR, 0.2; 95% CI, 0.1 to 0.6) and stereotactic radiosurgery (OR, 2.8; 95% CI, 1.3 to 6.1), and the choice of modality varied within some Spetzler-Martin grades. Conclusions— Patient characteristics and patterns of AVM interventional treatment differ between neuroscience centers in the same population necessitating careful consideration of these factors when comparing one hospital’s outcome with another.

Relative risk of hemorrhage during pregnancy in patients with brain arteriovenous malformations

Background It is unclear whether the risk of bleeding from brain arteriovenous malformations is higher during pregnancy, delivery, or puerperium. We compared occurrence of brain arteriovenous malformation hemorrhage in women during this period with occurrence of hemorrhage outside this period during their fertile years. Methods We included all women with ruptured brain arteriovenous malformations (16–41 years) from a retrospective database of patients with brain arteriovenous malformations in four Dutch university hospitals (n = 95) and from the population-based Scottish Audit of Intracranial Vascular Malformations (n = 44). We estimated the relative rate of brain arteriovenous malformation rupture (before any treatment) during exposed time (pregnancy, delivery, puerperium) versus non-exposed time during fertile years, using the case-crossover design as primary analysis, and the self-controlled case-series design as secondary analysis. Results In 17 of 95 Dutch women and in 3 of 44 Scottish women, hemorrhages occurred while pregnant; none occurred during delivery or puerperium. In Dutch women, the relative rate of brain arteriovenous malformation rupture during pregnancy, delivery, or puerperium was 6.8 (95% confidence interval 3.6–13) according to the case-crossover method and 7.1 (95% confidence interval 3.4–13) using the self-controlled case-series method. In Scottish women, the relative rate was 1.3 (95% confidence interval 0.39–4.1) using the case-crossover method and 1.7 (95% confidence interval 0.0–4.4) according to the self-controlled case-series method. Because of limited overlap of confidence intervals, we refrained from pooling the cohorts. Conclusions Case-crossover and self-controlled case series analyses reveal an increase in relative rate of brain arteriovenous malformation rupture during pregnancy in the Dutch cohort but not in the Scottish cohort. Since point estimates varied between both cohorts and numbers are relatively small, the clinical implications of our findings are uncertain.