Assessment of Cerebral Blood Flow with Micro-Doppler Vascular Reduces the Risk of Ischemic Stroke During the Clipping of Intracranial Aneurysms.

OBJECTIVE: To analyze the impact of the introduction of Micro-Doppler vascular (MDV) as a method of cerebral blood flow analysis during microsurgical clipping of intracranial aneurysms to check the partial occlusion of the aneurysm and the occurrence of stenosis by comparing these results with those provided by the postoperative digital subtraction angiography (DSA) scan as well as the occurrence of ischemic infarction on the postoperative computed tomography (CT) images. PATIENTS AND METHODS: We reviewed retrospectively the last 50 patients operated on before the introduction of the MDV (group 1) compared with the first 50 patients operated on using this technique (group 2). RESULTS: Nine (18%) of the 50 patients evaluated in the group 1 showed a new hypodensity in the postoperative CT images, whereas only 2 (4%) patients showed infarction in the group 2 (P = 0.02). In addition, in the group 1, 10 (20%) patients presented unexpected findings on DSA images (residual aneurysms, stenosis, and arterial occlusion), whereas in the group 2, those unexpected DSA findings were observed in only 3 (6%) patients (P = 0.023). CONCLUSION: MDV is an excellent method for cerebral blood flow assessment during the microsurgical clipping of intracranial aneurysms, reducing the unexpected angiographic results (residual aneurysms, stenosis, and arterial occlusion), as well as reducing the incidence of ischemic infarction on postoperative CT images, evidence of the positive impact of this method in the microsurgical treatment of intracranial aneurysms.

Statins and subarachnoid hemorrhage in Medicare patients with unruptured cerebral aneurysms.

BACKGROUND: Statins have been shown to decrease aneurysm progression and rupture in two experimental settings: animals with cerebral aneurysm and humans with abdominal aortic aneurysms. AIMS: To investigate statin use and outcomes in humans with unruptured cerebral aneurysms through Medicare administrative data. METHODS: We used a 40% random sample Medicare denominator file and corresponding inpatient, outpatient (2003-2011), and prescription (2006-2011) claims to conduct a retrospective cohort study of patients diagnosed with unruptured cerebral aneurysms, between 2003 and 2011. We used propensity score-adjusted models to investigate the association between statin use and risk of subarachnoid hemorrhage. Secondary analyses repeated the main models stratified on tobacco use status and separately assessed other composite outcomes. RESULTS: We identified 28 931 patients with unruptured cerebral aneurysms (average age 72·0 years, 72·6% female); mean follow-up was 30·0 months; 41·3% used statins. Overall, 593 patients developed subarachnoid hemorrhage, and 703 underwent treatment before subarachnoid hemorrhage. Current or recent statin use was not associated with a difference in subarachnoid hemorrhage risk (odds ratio, 1·03; 95% conflict of interest 0·86-1·23); models stratified on tobacco use status were nearly identical. No association was observed between statin use and the composite outcome of subarachnoid hemorrhage or aneurysm treatment (odds ratio, 0·94; 95% conflict of interest, 0·84-1·06). The risk of subarachnoid hemorrhage or out-of-hospital death was lower among statin users (odds ratio, 0·69; 95% conflict of interest, 0·64-0·74). CONCLUSIONS: Statin use by patients with unruptured cerebral aneurysms was not associated with subarachnoid hemorrhage risk. Given the prior animal experimental studies demonstrating a protective effect, further prospective studies are needed to investigate the potential relationship.

A novel grading scale for the angiographic assessment of intracranial aneurysms treated using flow diverting stents.

Flow diverting stents are emerging as a treatment option for difficult intracranial aneurysms. Current grading scales for assessment of angiographic outcomes following aneurysm treatment do not apply to aneurysms treated by flow diversion. We propose a novel grading scale based on the degree of angiographic filling and contrast stasis. This scale will facilitate communication and standardize reporting of outcomes following flow diversion treatments.

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.

Cost-effectiveness of preventive treatment of intracranial aneurysms: new data and uncertainties.

BACKGROUND: Previous modeling studies on treatment of unruptured intracranial aneurysms largely disregarded detailed data on treatment risks and omitted several factors that could influence cost-effectiveness. We performed a cost-effectiveness analysis of surgical and endovascular treatment of unruptured aneurysms for different rupture rates and life expectancies, and assessed the influence of excess mortality risks in these persons, de novo development of aneurysms, and utility of awareness of having an untreated aneurysm, and also identified important factors for which data are lacking. METHODS: We used a Markov model to compare surgical, endovascular, and no treatment of unruptured intracranial aneurysms. Inputs for the model were taken mainly from meta-analyses. Direct medical costs were derived from Dutch cost studies and expressed in 2005 Euros. We performed sensitivity analyses to evaluate model robustness. RESULTS: For 50-year-old patients, treatment of unruptured aneurysms is cost-effective for all rupture rate scenarios between 0.3% and 3.5%/year. In 70-year-old patients, treatment is not cost-effective in men with rupture rates < or =1%/year and women with rupture rates < or =0.5%/year. With lower utility of awareness of an untreated aneurysm, the cost-effectiveness of treatment strongly increased. The effect of excess mortality risks on the incremental cost-effectiveness ratios was modest. The risk of formation of new aneurysms had no relevant impact. CONCLUSIONS: Patients' life expectancy, risk of rupture, and utility of awareness of an untreated aneurysm mainly define cost-effectiveness. However, important uncertainties remain on the rupture risk according to size and location of the aneurysm and on the utility of awareness of untreated aneurysm. More data on these factors are needed to define and individualize cost-effectiveness analyses.

Do intraindividual variation in disease progression and the ensuing tight window of opportunity affect estimation of screening benefits?

BACKGROUND: The effects of variation in disease progression between individuals on the effectiveness of screening have been assessed extensively in the literature. For several diseases, progression may also vary within individuals over time. The authors study the effects of intraindividual variation and the combined effects of inter- and intraindividual variation in disease progression on the effectiveness of screening. METHODS: The authors investigated the risk reduction of aneurysmal subarachnoid hemorrhage (SAH) achieved by screening for intracranial aneurysms in a simulation study as a function of the inter- and intraindividual variation in the risk of aneurysm rupture. They also extended a previously constructed Markov model for the cost-effectiveness analysis of screening for new aneurysms in patients with clipped aneurysms after SAH. A time-varying risk of aneurysm rupture was introduced, and the influence of this variation on cost-effectiveness was assessed. RESULTS: The risk reduction provided by screening decreased with increasing intraindividual variation in disease progression. The expected number of prevented instances of SAH was overestimated by 58% in this simulation study when high degrees of inter- and intraindividual variation were present. Interindividual variation alone resulted in up to 33% overestimation and intraindividual variation in up to 43% overestimation. In the extended Markov model, screening benefits were overestimated by 24% when a high degree of intraindividual variation was present but ignored. CONCLUSIONS: If intraindividual variation in disease progression is ignored in decision models, subsequent cost-effectiveness analyses of screening strategies will overestimate the benefits provided by screening. This bias is comparable to, but partially independent of, the bias caused by ignoring interindividual heterogeneity.

Yield of screening for new aneurysms after treatment for subarachnoid hemorrhage.

OBJECTIVE: Patients who have been successfully treated for subarachnoid hemorrhage (SAH) are at risk for new episodes. The authors studied the effect of screening with CT angiography (CTA) for new aneurysms. METHODS: In a decision model, the authors compared the strategies "screening" and "no screening" after SAH. A literature review yielded the risks of aneurysm recurrence, complications of CTA, and re-treatment. The authors estimated the expected number of quality-adjusted life-years (QALYs), the number of SAH, and the mortality and disability rates for both strategies. They evaluated screening at intervals of 2, 5, and 10 years after SAH, using 10 years and remaining life expectancy as time horizon. RESULTS: The expected number of QALYs 10 years after clipping was virtually the same for no screening (8.33), screening once after 5 years (8.28), and screening every 2 years (8.27). With screening every 2 years, the expected rate of new SAH decreased from 1.9 to 0.5%, and mortality decreased from 0.9 to 0.6%; however, the disability rate increased from 0.5 to 1.9%. Results were comparable with remaining life expectancy as time horizon and for screening after initial treatment with coils. The key estimates of the analyses were the incidence and rupture rate of new aneurysms, the risk of dying from recurrent SAH, the utility of disability, and the risk of complications from DSA and re-treatment. CONCLUSIONS: Presently, screening for new aneurysms after subarachnoid hemorrhage cannot be recommended. Screening may prevent new episodes of subarachnoid hemorrhage but with too high a cost in terms of complications from preventive treatment.

Risks and benefits of screening for intracranial aneurysms in first-degree relatives of patients with sporadic subarachnoid hemorrhage.

BACKGROUND: The first-degree relatives of patients who have subarachnoid hemorrhage from ruptured intracranial aneurysms are themselves at risk for subarachnoid hemorrhage. We studied the benefits and risks of screening for aneurysms in the first-degree relatives of patients with sporadic subarachnoid hemorrhage. METHODS: We screened 626 first-degree relatives (parents, siblings, or children) of 160 patients with sporadic subarachnoid hemorrhage, from a prospective series of 193 consecutive index patients. Magnetic resonance angiography was the screening tool, and conventional angiography was used as the reference test in subjects thought to have aneurysms. Six months after elective operation, outcome was assessed by means of the modified Rankin scale of neurologic function. This observational study design was combined with a decision-analysis model to estimate the effectiveness of screening. The efficiency of screening was defined by the number of relatives who needed to be screened in order to prevent one subarachnoid hemorrhage. RESULTS: Aneurysms were found in 25 of 626 first-degree relatives (4.0 percent; 95 percent confidence interval, 2.6 to 5.8 percent). Eighteen underwent surgery, which resulted in a decrease in function in 11 (disabling in 1). Five had aneurysms that were 5 to 11 mm in diameter, 11 had aneurysms that were less than 5 mm, and 2 had both small and medium-sized aneurysms. On average, surgery increased estimated life expectancy by 2.5 years for these 18 subjects (or by 0.9 month per person screened), at the expense of 19 years of decreased function per person. The number of relatives who would need to be screened in order to prevent 1 subarachnoid hemorrhage on a lifetime basis was 149, and 298 would have to be screened in order to prevent 1 fatal subarachnoid hemorrhage. CONCLUSIONS: Implementation of a screening program for the first-degree relatives of patients with sporadic subarachnoid hemorrhage does not seem warranted at this time, since the resulting slight increase in life expectancy does not offset the risk of postoperative sequelae.

Cost-effective screening for cerebral aneurysms.

The advent of accurate, noninvasive angiography has raised hopes that premorbid screening for cerebral aneurysm will soon be possible. This article discusses the medical and economic issues which will determine the appropriate conditions for, and cost-effectiveness of, large-scale aneurysm screening.

Management of symptomatic and asymptomatic unruptured aneurysms.

Intradural unruptured saccular aneurysms are being diagnosed with increasing frequency. Left untreated, these lesions usually progress, and the cumulative risk from bleeding usually outweighs the risk of treatment. Exceptions include patients with limited life expectancy and patients over the age of 70 with small asymptomatic or giant posterior circulation lesions associated with few symptoms. Therapeutic intervention offers little over the natural history for these patients, and therapy should be considered only if symptoms progress or growth is documented. Treatment options should be coordinated by an experienced cerebrovascular surgeon with access to interventional adjuncts; EC-IC bypass, and circulatory arrest. GDC coiling should be reserved for non-surgical cases, as the durability of this treatment is still being evaluated.

Current implications for the efficacy of noninvasive screening for occult intracranial aneurysms in patients with a family history of aneurysms.

Although the technology exists for accurate noninvasive screening for intracranial aneurysms, the efficacy of screening depends on several key parameters of the natural history of aneurysms. Recent studies suggest that the prevalence of intracranial aneurysms may reach 20% in the subpopulation of patients with a family history of these lesions; other key parameters are less certain. The authors investigated factors that impact the efficacy of screening to establish interim guidelines. Three plausible models for the natural history of aneurysms were constructed. For each model the monetary cost of screening and the average gain in life expectancy were computed for a range of screening ages and prevalence rates. It is shown that the efficacy of screening depends on the pattern of aneurysm rupture. If aneurysms develop and rupture rapidly, then screening has no benefit. On the other hand, if aneurysms remain at risk for some time after formation, then screening may improve average life expectancy depending on when it occurs. The authors recommend that patients with a positive family history of aneurysms who are 30 years of age or younger be screened. This recommendation is based on the belief that the gains attributable to screening, assuming a constant rupture rate, outweigh the losses attributable to screening using a decreasing rupture rate model.