Long-term follow-up of unruptured intracranial aneurysms repaired in California

A Nationwide Analysis of Aneurysmal Subarachnoid Hemorrhage Mortality, Complications, and Health Economics in the USA

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating neurological condition. Endovascular coiling or surgical clipping have equivocal success rates, but relatively little is known regarding the health economics and complications of these procedures at the population level. We aimed to analyze the complication profiles and healthcare resource utilization (HRCU) associated with the treatment of aSAH in the USA. We performed a retrospective analysis utilizing the IBM MarketScan database between 2008 and 2015. Primary outcomes included economic analysis stratified by post-operative complication; determination of the effect of several factors on total cost by multivariable regression; and analysis of the incidence, timing, and associated HCRU of aSAH-related post-operative complications. Of the 2374 patients meeting inclusion criteria for economic analysis, 1783 (75.1%) patients had at least one of the ten complications. The most common complications included hydrocephalus (43.8%), transient cerebral ischemia (including vasospasm) (30.6%), ischemic stroke (29.1%), syndrome of inappropriate antidiuretic hormone (SIADH)/hyposmolarity/hyponatremia (22.1%), and seizures (14.9%). Patients who experienced complications had higher median 90-day total costs [$161,127 (Q1 to Q3, $101,411 to $257,662)] than those who did not [$97,376 (Q1 to Q3, $55,692 to $147,447)]. Length of stay was longest for those with pulmonary embolism and pneumonia (27 days) and shortest for those with SIADH/hyposmolarity/hyponatremia (16 days). Brain compression/herniation had the highest mortality rate (19.5%). In total, 14.6% of all patients experienced a readmission within 30 days. In conclusion, patients with aSAH have high post-operative complication rates and costs. Development of novel interventions to reduce complications and improve outcomes is crucial.

Predictive value of IOM in clipping of unruptured intracranial aneurysms - A prospective study from the surgeon's point of view

Introduction

Intraoperative neuromonitoring (IOM) of motor/somatosensory evoked potentials is a well-established approach for reducing ischemic complications after aneurysm clipping.

Research question

To determine the predictive validity of IOM for postoperative functional outcome and its perceived added value for intraoperative real-time feedback of functional impairment in the surgical treatment of unruptured intracranial aneurysms (UIAs).

Material and methods

Prospective study of patients scheduled for elective clipping of UIAs between 02/2019-02/2021. Transcranial motor evoked potentials (tcMEP) were used in all cases, a significant decline was defined as loss of ≥50% in amplitude or 50% latency increase. Clinical data were correlated to postoperative deficits. A surgeon's questionnaire was conceived.

Results

47 patients were included, median age 57 years (range 26-76). IOM was successful in all cases. In 87.2%, IOM was stable throughout surgery, although 1 patient (2.4%) demonstrated a permanent postoperative neurological deficit. All patients with an intraoperatively reversible tcMEP-decline (12.7%) showed no surgery-related deficit, regardless of the decline duration (range 0.5-40.0 ​min; mean: 13.8). Temporary clipping (TC) was performed in 12 cases (25.5%), with a decline in amplitude in 4 patients. After clip-removal, all amplitudes returned to baseline. IOM provided the surgeon with a higher sense of security in 63.8%.

Discussion and conclusion

IOM remains invaluable during elective microsurgical clipping, particularly during TC of MCA and AcomA-aneurysms. It alerts the surgeon of impending ischemic injury and offers a way of maximizing the time frame for TC. IOM has highly increased surgeons' subjective feeling of security during the procedure.

The first coil embolization ratio is the key factor for retreatment for unruptured cerebral aneurysms

Background

In coil embolization, a high volume embolization ratio prevents recanalization that may require retreatment. However, patients with a high volume embolization ratio may also require retreatment. Patients with inadequate framing with the first coil may experience recanalization of the aneurysm. We analyzed the relationship between embolization ratio of the first coil and recanalization requiring retreatment.

Methods

We reviewed data from 181 patients with unruptured cerebral aneurysms who underwent initial coil embolization between 2011 and 2021. We retrospectively analyzed the correlation between neck width, maximum aneurysm size, width, aneurysm volume, volume embolization ratio of the framing coil (first volume embolization ratio [1^st VER]), and final volume embolization ratio (final VER) of cerebral aneurysms in patients and their retreatment.

Results

Recanalization requiring retreatment was observed in 13 patients (7.2%). The factors related to recanalization were neck width, maximum aneurysm size, width, aneurysm volume, and 1^st VER, but not the final VER. Multivariate analysis of the five factors showed a significant difference in the 1^st VER (P = 0.002). The cutoff value for recanalization was a 1^st VER of 5.8%. There were 162 cases with a VER ≥ 20% or higher, and the same analysis yielded similar results.

Conclusion

The 1^st VER was significantly correlated with recanalization of cerebral aneurysms requiring retreatment. In coil embolization of unruptured cerebral aneurysms, it is important to achieve an embolization rate of at least 5.8% using a framing coil to prevent recanalization.

European Stroke Organisation (ESO) guidelines on management of unruptured intracranial aneurysms

Unruptured intracranial aneurysms (UIA) occur in around 3% of the population. Important management questions concern if and how to perform preventive UIA occlusion; if, how and when to perform follow up imaging and non-interventional means to reduce the risk of rupture. Using the Standard Operational Procedure of ESO we prepared guidelines according to GRADE methodology. Since no completed randomised trials exist, we used interim analyses of trials, and meta-analyses of observational and case-control studies to provide recommendations to guide UIA management. All recommendations were based on very low evidence. We suggest preventive occlusion if the estimated 5-year rupture risk exceeds the risk of preventive treatment. In general, we cannot recommend endovascular over microsurgical treatment, but suggest flow diverting stents as option only when there are no other low-risk options for UIA repair. To detect UIA recurrence we suggest radiological follow up after occlusion. In patients who are initially observed, we suggest radiological monitoring to detect future UIA growth, smoking cessation, treatment of hypertension, but not treatment with statins or acetylsalicylic acid with the indication to reduce the risk of aneurysm rupture. Additionally, we formulated 15 expert-consensus statements. All experts suggest to assess UIA patients within a multidisciplinary setting (neurosurgery, neuroradiology and neurology) at centres consulting >100 UIA patients per year, to use a shared decision-making process based on the team recommendation and patient preferences, and to repair UIA only in centres performing the proposed treatment in >30 patients with (ruptured or unruptured) aneurysms per year per neurosurgeon or neurointerventionalist. These UIA guidelines provide contemporary recommendations and consensus statement on important aspects of UIA management until more robust data come available.

Intraoperative fluorescein video angiography in intracranial aneurysm surgery: single-center, observational cohort study

The aim of this study was to compare the incidence of postoperative, surgery-related complications in patients where fluorescein video angiography (FL-VA) was performed with those operated without intraoperative verification. This is an observational cohort study including 97 patients who were selected for microsurgical clipping due to intracranial aneurysm. First 52 patients enrolled in the study were operated prior to introduction of fluorescein fluorescence in our surgical workflow. These patients were considered as controls. The study group consisted of 45 consecutive patients operated with the use of fluorescein video angiography and by the same surgical team. Outcomes in both groups were compared using non-parametric test (Mann-Whitney U). Intraoperative fluorescein video angiography revealed aneurysm remnant or inadvertent vessel occlusion in 17.8% of patients. Following clip reposition, a repeated FL-VA was performed to confirm restoration of blood flow and/or complete aneurysm obliteration. Intraoperative findings were later confirmed using computed tomography angiography (CTA). None of the patients in our study group developed surgery-related complications; whereas in the control group, aneurysm remnant was discovered in 7.7%, brain ischemia in 9.6% and both of the latter in 5.8% of patients. Difference in treatment-related outcome was statistically significant (p < 0.05). Intraoperative fluorescein video angiography successfully identified aneurysm residual and adjacent artery occlusion leading to excellent outcome following clip reposition.

Risk factors for periprocedural ischemic stroke following endovascular treatment of intracranial aneurysms

Background

The aim of this study was to comprehensively evaluate the risk factors of periprocedural ischemic stroke associated with endovascular treatment of intracranial aneurysms using a real-world database.

Methods

From August 2016 to March 2017, 167 patients were enrolled. Univariate analysis and multivariate logistic regression analysis were used to examine the risk factors for periprocedural ischemic stroke.

Results

Among the 167 cases, periprocedural ischemic stroke occurred in 20 cases (11.98%). After univariate analysis, the ischemic group had a higher proportion of large (≥ 10 mm) aneurysms than the control group (45.0% vs. 23.1%, p = 0.036). The incidence of periprocedural ischemic stroke was higher in cases treated by flow diverter (21.6%) or stent-assisted coiling (11.8%) than in cases treated by coiling only (2.7%), and the differences were statistically significant (p = 0.043). After multivariate logistic regression analysis, treatment modality was the independent risk factor for periprocedural ischemic stroke. Compared with the coiling-only procedure, flow diverter therapy was associated with a significantly higher rate of periprocedural ischemic stroke (OR 9.931; 95% CI 1.174–84.038; p = 0.035).

Conclusions

Aneurysm size and treatment modality were associated with periprocedural ischemic stroke. Larger aneurysms were associated with increased risk of periprocedural ischemic stroke. Flow diverter therapy was associated with significantly more periprocedural ischemic stroke than the coiling procedure alone.

Short- and midterm outcome of ruptured and unruptured intracerebral wide-necked aneurysms with microsurgical treatment

To clip or coil has been matter of debates for several years and is the domain of interdisciplinary decision making. However, the microsurgical outcome has still been elusive concerning wide neck aneurysms (WNA). A retrospective single center study was performed with all patients with ruptured WNA (rWNA) and unruptured WNA (uWNA) admitted to author´s institute between 2007–2017. Microsurgical outcome was evaluated according to Raymond-Roy occlusion grade and follow-up angiography was performed to analyze the stability of neck/aneurysm remnants and retreatment poverty. Of 805 aneurysms, 139 were rWNA (17.3%) and 148 uWNA (18.4%). Complete occlusion was achieved in 102 of 139 rWNA (73.4%) and 112 of 148 uWNA (75.6%). Neck remnants were observed in 36 patients with rWNA (25.9%) and 30 patients with uWNA (20.3%), 1 (0.7%) and 6 (4.1%) patients had aneurysmal remnant, respectively. Overall complication rate was 11.5%. At follow-up (939/1504 months), all remnants were stable except for one, which was further conservatively treated with marginal retreatment rate under 1%. Even the risk of de-novo aneurysm was higher than the risk for remnant growth (2.6% vs 0% in rWNA; 8.7% vs 5.3% in uWNA) without significant difference. Microsurgical clipping is effective for complete occlusion of r/uWNA with low complication. Furthermore, the risk of remnant growth is marginal even lower than the risk of de-novo rate low retreatment rate.

Long-term outcomes of endovascular simple coiling versus neurosurgical clipping of unruptured intracranial aneurysms: A systematic review and meta-analysis

BACKGROUND

Previous studies on ruptured intracranial aneurysms have shown favourable long-term outcomes of patients undergoing endovascular coiling compared to neurosurgical clipping. We aimed to evaluate if these results also apply to patients with unruptured intracranial aneurysms (UIAs).

METHODS

Embase, PubMed, and Cochrane Library were systematically searched for all studies reporting long-term (≥3 years) follow-up after coiling or clipping of UIAs. Thirteen studies involving 16,622 coiled patients and 13,606 clipped patients were included. Short-term outcome was defined as death ≤30 days after treatment. Long-term outcomes (>3 years) included all-cause mortality, morbidity (defined as modified Rankin Score 3-5 or Glasgow Outcome Score 2-3), cerebrovascular accident, intracerebral haemorrhage, additional repairs, and lost to follow-up. We calculated relative risk (RR), incidence and mortality rates (IR and MR), together with incidence and mortality rate ratio (IRR and MRR).

RESULTS

Patients treated with simple coiling had lower short-term mortality than clipped patients (RR = 0.62 (95%CI 0.42-0.91)), but this difference disappeared after long-term follow-up ((MRR) = 0.89 (95%CI: 0.78-1.02). Coiled patients had higher retreatment rates than clipped patients (IRR = 1.70 (95%CI 1.50-1.93)).

CONCLUSIONS

This systematic review and meta-analysis reports benefits and drawbacks of simple coiling versus neurosurgical clipping of UIAs. Future studies with longer follow-up time should account for differences in coiling techniques and confounding factors such as size and location of UIAs.

Reduced 2-year aneurysm retreatment and costs among patients treated with flow diversion versus non-flow diversion embolization: A Premier Healthcare Database retrospective cohort study

Introduction

The use of endovascular treatments, including Pipeline embolization devices (PEDs) and coiling approaches (non-PEDs), has played an increasingly important role in the treatment of intracranial aneurysms. Despite multiple studies evaluating PEDs, a real-world evaluation of follow-up outcomes and costs remains to be completed.

Methods

The Premier Healthcare Database (PHD), 2010–2017, was queried to identify patients with unruptured intracranial aneurysms treated endovascularly. Rates of readmission, retreatment, and cost at the same hospital were compared between patients who underwent PED and non-PED endovascular treatments of their aneurysms. One-to-three (PED–to–non-PED) propensity score (PS) matching was performed to adjust for potential case selection bias into the PED cohort, with covariates including age group, sex, Charlson Comorbidity Index (CCI) group, payor, region, and randomized hospital identifier.

Results

A total of 679 patients underwent PED placement and 8432 had non-PED treatments. Prior to PS matching, there were significant but minor differences in age (56.7±12.8 vs. 58.2±12.6 years, p = 0.004) and sex (male 16.6% vs. 24.4%, p<0.0001) for PED and non-PED, respectively, but no differences in CCI (p = 0.08), length of stay (p = 0.88), or rate of routine discharge (p = 0.21). All-cause readmission/emergency department reevaluation rates in the two cohorts were similar at 30, 90, and 180 days and 1 and 2 years. Our results identified a significantly lower retreatment rate for PEDs at all follow-up time points over a 2-year period (range: 0.9–8.1%) compared with non-PED treatments (range: 1.7–11.6%). These findings remained consistent after PS matching: all-cause readmission/reevaluation rates were significantly lower in patients treated with PED at 90 days, 180 days, 1 year, and 2 years (p<0.001). Although the initial treatment costs were higher for PED at time of treatment (p<0.001), cumulative follow-up emergency department visit and readmission costs (inclusive of patients with no readmission and/or no retreatment) were significantly lower for patients with initial PED relative to non-PED treatment at 2 years (p = 0.021).

Conclusions

These results suggest that PEDs may potentially reduce downstream retreatment rates and costs. Further work is required to improve identification of patient subgroups that could benefit from PED over non-PED treatments both initially and during follow-up.

Initial Treatment for Unruptured Intracranial Aneurysm and Its Follow-up: A Cost Analysis of Pipeline Flow Diverters versus Coiling

Purpose

Intracranial aneurysms are relatively common epidemiological problems for which the surveillance, treatment, and follow-up are costly. Although multiple studies have evaluated the treatment cost of aneurysms, the follow-up costs are often not examined. In our study, we analyzed how follow-up costs after treatment affected the overall cost of different endovascular techniques for treating aneurysms.

Materials and methods

An institutional database was used to evaluate the upfront and follow-up costs incurred by patients who underwent elective coiling or placement of a pipeline embolization device (PED) for the treatment of unruptured intracranial aneurysms from July 2011 to December 2017.

Results

A total of 114 patients (coiling, n = 37; PED, n = 77 ) were included in the study. There was no significant difference among patients in mean age [61.3 (±12.8 years) vs. 57.0 (±14.5 years); probability value (p) = 0.2], sex (male: 32.4% vs. 22.1%; p = 0.2), American Society of Anesthesiologists (ASA) grade (p = 0.5), discharge disposition (p = 0.1), mean length of stay [3.1 days (±5.5) vs. 2.4 days (±2.6); p = 0.2) or follow-up period [22.7 months (±18.5) vs. 18.6 months (±14.9); p = 0.2). There were no differences in costs during admission (p = 0.5) or in follow-up (p = 0.3) between coiling and PED treatments. Initial costs were predominantly related to supplies/implants (56.1% vs. 63.7%) for both treatments. Follow-up costs mostly comprised facility costs (68.2% vs. 67.5%), and there were no differences in costs of subgroups such as supplies/implants (10.5% vs. 9.4%), imaging (17.0% vs. 17.8%), or facilties between coiling and PED.

Conclusion

These results suggest that the upfront and follow-up costs are mostly similar for the treatment of intracranial aneurysms irrespective of whether the providers used coiling or PED endovascular techniques. Hence, we conclude that follow-up costs should not be a deciding factor when considering these treatments.

Clinical outcomes and cost-effectiveness analysis for the treatment of basilar tip aneurysms

Background

Endovascular treatment of basilar tip aneurysms is less invasive than microsurgical clipping, but requires closer follow-up.

Objective

To characterize the additional costs associated with endovascular treatment of basilar tip aneurysms rather than microsurgical clipping.

Materials and methods

We obtained clinical records and billing information for 141 basilar tip aneurysms treated with clip ligation (n=48) or endovascular embolization (n=93). Costs included direct and indirect costs associated with index hospitalization, as well as re-treatments, follow-up visits, imaging studies, rehabilitation, and disability. Effectiveness of treatment was quantified by converting functional outcomes (modified Rankin Scale (mRS) score) into quality-adjusted life-years (QALYs). Cost-effectiveness was performed using cost/QALY ratios.

Results

Average index hospitalization costs were significantly higher for patients with unruptured aneurysms treated with clip ligation ($71 400 ± $47 100) compared with coil embolization ($33 500 ± $22 600), balloon-assisted coiling ($26 200 ± $11 600), and stent-assisted coiling ($38 500 ± $20 900). Multivariate predictors for higher index hospitalization cost included vasospasm requiring endovascular intervention, placement of a ventriculoperitoneal shunt, longer length of stay, larger aneurysm neck and width, higher Hunt-Hess grade, and treatment-associated complications. At 1 year, endovascular treatment was associated with lower cost/QALY than clip ligation in unruptured aneurysms ($52 000/QALY vs $137 000/QALY, respectively, p=0.006), but comparable rates in ruptured aneurysms ($193 000/QALY vs $233 000/QALY, p=0.277). Multivariate predictors for higher cost/QALY included worse mRS score at discharge, procedural complications, and larger aneurysm width.

Conclusions

Coil embolization of basilar tip aneurysms is associated with a lower cost/QALY. This effect is sustained during follow-up. Clinical condition at discharge is the most significant predictor of overall cost/QALY at 1 year.

Pipeline Endovascular Device vs Stent-Assisted Coiling in Small Unruptured Aneurysms: A Cost-Effectiveness Analysis

BACKGROUND

Both stent-assisted coiling (SAC) and flow diversion with the Pipeline Embolization device (PED; Medtronic Inc) have been shown to be safe and clinically effective for treatment of small (<10 mm) unruptured aneurysms. However, the economic impact of these different techniques has not been established.

OBJECTIVE

To analyze the cost-effectiveness between stent-assisted coiling and flow diversion using PED, including procedural costs, long-term outcomes, and aneurysm recurrence.

METHODS

A decision-analytical study was performed with Markov modeling methods to simulate patients undergoing SAC or PED for treatment for unruptured aneurysms of sizes 5 and 7 mm. Input probabilities were derived from prior literature, and 1-way, 2-way, and probabilistic sensitivity analyses (PSA) were performed.

RESULTS

In base case calculation and PSA, PED was the dominant strategy for both the size groups, with and without consideration of indirect costs. One-way sensitivity analyses show that the conclusion remained robust when varying the retreatment rate of SAC from 0% to 50%, and only changes when the retreatment rate of PED > 49%. PED remained the more cost-effective strategy when the morbidity and mortality of PED increased by <55% and when those of SAC decreased by <37%. SAC only became cost-effective when the total cost of PED is >$73000 more expensive than the total cost of SAC.

CONCLUSION

With increasing use of PED for treatment of small unruptured anterior circulation aneurysms, our study indicates that PED is cost-effective relative to stent coiling irrespective of aneurysm size. This is due to lower aneurysm recurrence rate, as well as better health outcomes.

Predictors of Recurrence, Progression, and Retreatment in Basilar Tip Aneurysms: A Location-Controlled Analysis

BACKGROUND

Endovascular treatment of intracranial aneurysms is associated with higher rates of recurrence and retreatment, though contemporary rates and risk factors for basilar tip aneurysms (BTAs) are less well-described.

OBJECTIVE

To characterize progression, retreatement, and retreated progression of BTAs treated with microsurgical or endovascular interventions.

METHODS

We retrospectively reviewed records for 141 consecutive BTA patients. We included 158 anterior communicating artery (ACoA) and 118 middle cerebral artery (MCA) aneurysms as controls. Univariate and multivariate analyses were used to calculate rates of progression (recurrence of previously obliterated aneurysms and progression of known residual aneurysm dome or neck), retreatment, and retreated progression. Kaplan-Meier analysis was used to characterize 24-mo event rates for primary outcome prediction.

RESULTS

Of 141 BTA patients, 62.4% were ruptured and 37.6% were unruptured. Average radiographical follow-up was 33 mo. Among ruptured aneurysms treated with clipping, there were 2 rehemorrhages due to recurrence (6.1%), and none in any other cohorts. Overall rates of progression (28.9%), retreatment (28.9%), and retreated progression (24.7%) were not significantly different between surgical and endovascular subgroups, though ruptured aneurysms had higher event rates. Multivariate modeling confirmed rupture status (P = .003, hazard ratio = 0.14) and aneurysm dome width (P = .005, hazard ratio = 1.23) as independent predictors of progression requiring retreatment. In a separate multivariate analysis with ACoA and MCA aneurysms, basilar tip location was an independent predictor of progression, retreatment, and retreated progression.

CONCLUSION

BTAs have higher rates of progression and retreated progression than other aneurysm locations, independent of treatment modality. Rupture status and dome width are risk factors for progression requiring retreatment.

Long-term outcomes of coil embolization of unruptured intracranial aneurysms

OBJECTIVELong-term follow-up results of the treatment of unruptured intracranial aneurysms (UIAs) by means of coil embolization remain unclear. The aim of this study was to analyze the frequency of rupture, retreatment, stroke, and death in patients with coiled UIAs who were followed for up to 20 years at multiple stroke centers.METHODSThe authors retrospectively analyzed data from cases in which patients underwent coil embolization between 1995 and 2004 at 4 stroke centers. In collecting the late (≥ 1 year) follow-up data, postal questionnaires were used to assess whether patients had experienced rupture or retreatment of a coiled aneurysm or any stroke or had died.RESULTSOverall, 184 patients with 188 UIAs were included. The median follow-up period was 12 years (interquartile range 11-13 years, maximum 20 years). A total of 152 UIAs (81%) were followed for more than 10 years. The incidence of rupture was 2 in 2122 aneurysm-years (annual rupture rate 0.09%). Nine of the 188 patients with coiled UIAs (4.8%) underwent additional treatment. In 5 of these 9 cases, the first retreatment was performed more than 5 years after the initial treatment. Large aneurysms were significantly more likely to require retreatment. Nine strokes occurred over the 2122 aneurysm-years. Seventeen patients died in this cohort.CONCLUSIONSThis study demonstrates a low risk of rupture of coiled UIAs with long-term follow-up periods of up to 20 years. This suggests that coiling of UIAs could prevent rupture for a long period of time. However, large aneurysms might need to be followed for a longer time.

Hospital case-volume is associated with case-fatality after aneurysmal subarachnoid hemorrhage

Background

Inverse association between hospital case-volume and case-fatality has been observed for various nonsurgical interventions and surgical procedures.

Aims

To study the impact of hospital case-volume on outcome after aneurysmal subarachnoid hemorrhage (aSAH).

Methods

We included aSAH patients who underwent aneurysm coiling or clipping from tertiary care medical centers across three continents using the Dr Foster Stroke GOAL database 2007–2014. Hospitals were categorized by annual case-volume (low volume: <41/year; intermediate: 41–70/year; high: >70/year). Primary outcome was 14-day in-hospital case-fatality. We calculated proportions, and used multiple logistic regression to adjust for age, sex, differences in comorbidity or disease severity, aneurysm treatment modality, and hospital.

Results

We included 8525 patients (2363 treated in low volume hospitals, 3563 treated in intermediate volume hospitals, and 2599 in high-volume hospitals). Crude 14-day case-fatality for hospitals with low case-volume was 10.4% (95% confidence interval (CI) 9.2–11.7%), for intermediate volume 7.0% (95% CI 6.2–7.9%; adjusted odds ratio (OR) 0.63 (95%CI 0.47–0.85)) and for high volume 5.4% (95% CI 4.6–6.3%; adjusted OR 0.50 (95% CI 0.33–0.74)). In patients with clipped aneurysms, adjusted OR for 14-day case-fatality was 0.46 (95% CI 0.30–0.71) for hospitals with intermediate case-volume and 0.42 (95% CI 0.25–0.72) with high case-volume. In patients with coiled aneurysms, adjusted OR was 0.77 (95% CI 0.55–1.07) for hospitals with intermediate case-volume and 0.56 (95% CI 0.36–0.87) with high case-volume.

Conclusions

Even within a subset of large, tertiary care centers, intermediate and high hospital case-volume is associated with lower case-fatality after aSAH regardless of treatment modality, supporting centralization to higher volume centers.

Long-term outcomes of treatment for unruptured intracranial aneurysms in South Korea: clipping versus coiling

Background

The long-term outcomes of endovascular coiling and surgical clipping for the treatment of unruptured intracranial aneurysms are unclear.

Methods

We performed a nationwide retrospective cohort study using claims data from the Korean Health Insurance Review and Assessment Service on patients undergoing surgical clipping or endovascular coiling from 2008 to 2014. Inverse probability treatment weighting for average treatment effect on the treated and the multiple imputation method were used to balance covariates and handle missing values. The primary outcome was all-cause mortality at 7 years.

Results

We identified 26 411 patients of whom 11 777 underwent surgical clipping and 14 634 underwent endovascular coiling. After adjustment with the use of inverse probability treatment weighting for average treatment effect on the treated, all-cause mortality rates at 7 years were 3.8% in the endovascular coiling group and 3.6% in the surgical clipping group (HR 1.05; 95% CI 0.86 to 1.28; P=0.60, log-rank test). The adjusted probabilities of aneurysm rupture at 7 years were 0.9% after endovascular coiling and 0.7% after surgical clipping (HR 0.9; 95% CI 0.61 to 1.34; P=0.63, log-rank test). The probabilities of retreatment at 7 years after adjustment were 4.9% in the endovascular coiling group and 3.2% in the surgical clipping group (HR 1.52; 95% CI 1.28 to 1.81; P<0.001, log-rank test).

Conclusions

All-cause mortality at 7 years was similar between the elective surgical clipping and endovascular coiling groups in patients with unruptured aneurysms who had no history of subarachnoid hemorrhage due to aneurysm rupture.

A long-term study of durability and risk factors for aneurysm recurrence after microsurgical clip ligation

OBJECTIVE

With the recent evolution of endovascular therapies, objective evaluation of the efficacy of clip ligation for cerebral aneurysms should be performed. This study was undertaken to evaluate the durability of microsurgical clip ligation, identify risk factors for recurrence, and assess the need for long-term follow-up imaging.

METHODS

A retrospective review of medical records identified 616 consecutive patients (156 male and 460 female patients; mean age 48.4 ± 12.4 years; range 6–90 years) who underwent microsurgical clip ligation and follow-up imaging at least 1 year after discharge between 1990 and 2010 at our institution. Of a total of 926 aneurysms in 616 patients, 758 aneurysms were microsurgically clip-ligated. At presentation, 431 of these aneurysms were ruptured and 327 aneurysms were unruptured. All patients underwent postoperative baseline imaging within the 1st month of their operation. A logistic regression analysis was performed to identify which variables are more likely to predict recurrence.

RESULTS

Late follow-up angiographic imaging was obtained at a mean of 7.2 ± 4.7 years postdischarge (median 5.7 years; range 1–23 years). Of the 699 clipped aneurysms without residua, late follow-up angiography revealed only 1 (0.14%) recurrent aneurysm. Of the 59 residual aneurysms that remained after initial clip ligation on early postoperative imaging, 8 (13.6%) demonstrated growth. All of these aneurysms required treatment. None of the recurrences were due to broken or delayed displacement of clips. A total of 111 patients presented with multiple aneurysms. De novo aneurysm formation occurred in 8 (0.97%) patients, all of whom initially presented with multiple aneurysms.

CONCLUSIONS

This study provides additional evidence to support the long-term efficacy of aneurysm clip ligation. The chance of aneurysm recurrence after complete clip ligation is very small. However, there is a regrowth risk of 1.83% per year for aneurysm remnants after incomplete clip ligation. These findings support the necessity for continued followup, late angiographic imaging, and the potential need for further intervention of incompletely ligated aneurysms. Furthermore, completely clip-ligated aneurysms may not require additional surveillance imaging unless multiple aneurysms were evident at presentation.

Comparison of clipping and coiling in elderly patients with unruptured cerebral aneurysms

OBJECTIVE The comparative effectiveness of the 2 treatment options-surgical clipping and endovascular coiling-for unruptured cerebral aneurysms remains an issue of debate and has not been studied in clinical trials. The authors investigated the association between treatment method for unruptured cerebral aneurysms and outcomes in elderly patients. METHODS The authors performed a cohort study of 100% of Medicare fee-for-service claims data for elderly patients who had treatment for unruptured cerebral aneurysms between 2007 and 2012. To control for measured confounding, the authors used propensity score conditioning and inverse probability weighting with mixed effects to account for clustering at the level of the hospital referral region (HRR). An instrumental variable (regional rates of coiling) analysis was used to control for unmeasured confounding and to create pseudo-randomization on the treatment method. RESULTS During the study period, 8705 patients underwent treatment for unruptured cerebral aneurysms and met the study inclusion criteria. Of these patients, 2585 (29.7%) had surgical clipping and 6120 (70.3%) had endovascular coiling. Instrumental variable analysis demonstrated no difference between coiling and clipping in 1-year postoperative mortality (OR 1.25, 95% CI 0.68-2.31) or 90-day readmission rate (OR 1.04, 95% CI 0.66-1.62). However, clipping was associated with a greater likelihood of discharge to rehabilitation (OR 6.39, 95% CI 3.85-10.59) and 3.6 days longer length of stay (LOS; 95% CI 2.90-4.71). The same associations were present in propensity score-adjusted and inverse probability-weighted models. CONCLUSIONS In a cohort of Medicare patients, there was no difference in mortality and the readmission rate between clipping and coiling of unruptured cerebral aneurysms. Clipping was associated with a higher rate of discharge to a rehabilitation facility and a longer LOS.

Microsurgical Clipping of Unruptured Intracranial Aneurysms: A Single Surgeon's Experience over 16 Years

BACKGROUND

Unruptured intracranial aneurysms (UIAs) have become an issue of greater significance as their detection rates have increased over the years. We present the overall experience of microsurgical clipping of unruptured aneurysms by a single surgeon over a period of more than 16 years.

METHODS

The clinical and radiologic data were reviewed retrospectively. Clinical outcome at follow-up was assessed with Glasgow Outcome Scale, and angiograms were reviewed for the degree of occlusion.

RESULTS

One hundred ninety-six patients with 221 UIAs were included in the analysis. The median age of patients was 54 years, with a female preponderance. Eighty-two percent of the patients had chronic headache on presentation. Middle cerebral artery aneurysms (32.2%) and posterior-inferior-cerebellar-artery aneurysms (46.1%) were most common in the anterior and posterior circulation, respectively. The perioperative complication rate was 17.3%. The overall surgical morbidity and mortality were 2.1% and 1.5%, respectively. With median follow-up of 11.3 months, 82% of patients were almost asymptomatic with a complete occlusion rate of 94%. The proportion of UIAs being coiled has significantly increased in the last decade, with a concomitant increase in the risk of poor clinical outcome after surgery.

CONCLUSION

Surgical clipping is effective and can provide a good long-term outcome. The most commendable consequence that it provides is a better long-term occlusion rate. The experience of the individual surgeon is important for a superior and enduring overall outcome. An increase in the rate of coiling in recent years has affected the outcome rate after surgery that calls for further evaluation.

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.

Preemptive Medicine for Cerebral Aneurysms

Most of cerebral aneurysms (CAs) are incidentally discovered without any neurological symptoms and the risk of rupture of CAs is relatively higher in Japanese population. The goal of treatments for patients with CAs is complete exclusion of the aneurysmal rupture risk for their lives. Since two currently available major treatments, microsurgical clipping and endovascular coiling, have inherent incompleteness to achieve cure of CAs with some considerable treatment risks, and there is no effective surgical or medical intervention to inhibit the formation of CAs in patients with ruptured and unruptured CAs, new treatment strategies with lower risk and higher efficacy should be developed to prevent the formation, growth, and rupture of CAs. Preemptive medicine for CAs should be designed to prevent or delay the onset of symptoms from CAs found in an asymptomatic state or inhibit the de novo formation of CAs, but we have no definite methods to distinguish rupture-prone aneurysms from rupture-resistant ones. Recent advancements in the research of CAs have provided us with some clues, and one of the new treatment strategies for CAs will be developed based on the findings that several inflammatory pathways may be involved in the formation, growth, and rupture of CAs. Preemptive medicine for CAs will be established with specific biomarkers and imaging modalities which can sensor the development of CAs.

Clinical outcome after surgical clipping or endovascular coiling for cerebral aneurysms: a pragmatic meta-analysis of randomized and non-randomized trials with short- and long-term follow-up

BACKGROUND

Two randomized trials have evaluated clipping and coiling in patients with ruptured aneurysms. Aggregated evidence for management of ruptured and unruptured aneurysms is missing.

OBJECTIVE

To conduct a meta-analysis evaluating clinical outcome after aneurysm treatment.

METHODS

PubMed, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov were searched for studies evaluating aneurysm treatment. The primary outcome measure was an independent clinical outcome (modified Rankin scale 0-2, Glasgow Outcome Scale 4-5, or equivalent). Secondary outcomes were poor outcome and mortality. ORs were calculated on an intention-to-treat basis with 95% CIs. Outcome heterogeneity was evaluated with Cochrane's Q test (significance level cut-off value at <0.10) and I² (significance cut-off value >50%) with the Mantel-Haenszel method for dichotomous outcomes. A p value <0.05 was regarded as statistically significant.

RESULTS

Searches yielded 18 802 articles. All titles were assessed, 403 abstracts were evaluated, and 183 full-text articles were read. One-hundred and fifty articles were qualitatively assessed and 85 articles were included in the meta-analysis. Patients treated with coiling (randomized controlled trials (RCTs)) had higher independent outcome at short-term follow-up (OR=0.67, 95% CI 0.57 to 0.79). Independent outcome was favored for coiling at intermediate and long-term follow-up (RCTs and observational studies combined-OR=0.80, 0.68 to 0.94 and OR=0.81, 0.71 to 0.93, respectively). Independent outcome and lower mortality was favored after coiling in unruptured aneurysms (database registry studies) at short-term follow-up (OR=0.34, 0.29 to 0.41 and OR=1.74, 1.52 to 1.98, respectively).

CONCLUSIONS

This meta-analysis evaluating clinical outcome after coiling or clipping for intracranial aneurysms, indicates a higher independent outcome and lower mortality after coiling.

Surgical Clipping of Very Small Unruptured Intracranial Aneurysms

BACKGROUND:

Treatment of very small unruptured intracranial aneurysms (VSUIAs, defined as ⩽3 mm) can be indicated in selected circumstances. The feasibility and outcomes of endovascular therapy for VSUIAs have been recently published; however, the efficacy and complication rate of surgical clipping has not been reported in any large series to date.

OBJECTIVE:

We conducted a multicenter study to examine surgical outcomes for VSUIAs.

METHODS:

All consecutive patients undergoing surgery for a VSUIA in 4 neurosurgical centers between October 2001 and December 2012 were retrospectively analyzed.

RESULTS:

In the study, 183 patients (128 women, mean age 51.3 years) were treated with 190 procedures for a total of 228 aneurysms. Most were anterior circulation aneurysms (n = 215). The majority were directly clipped (n = 222, 97.4%), with coagulation or wrapping in the remainder. After 1 reoperation for incomplete clipping, postoperative imaging of 225 aneurysms confirmed complete occlusion in 221 (98.2%), 1 neck remnant (0.44%), and 3 partial occlusions (1.3%). Mortality was 0%. Early postoperative neurological deficit developed in 12 patients (6.6%); posterior circulation location was a significant risk factor for early neurological deficit (P &lt; .001). Middle cerebral artery aneurysms had the lowest rate of postoperative deficits at 1.5% (P = .023). After the initial 30-day perioperative period, all deficits related to treatment of posterior circulation aneurysms recovered; overall neurological morbidity decreased to 2.7% with no mortality.

CONCLUSION:

VSUIA clipping is highly effective and is associated with a low morbidity rate. For VSUIAs selected for treatment, our data support surgical clipping as the modality of choice.

Effects of anatomic characteristics of aneurysms on packing density in endovascular coil embolization: analysis of a single center's experience

When embolizing cerebral aneurysms, dense coil packing may prevent recanalization but this may be influenced by the aneurysm morphology. We have analyzed retrospectively the relationship between anatomic features and the volumetric coil packing density. We analyzed 452 aneurysms in 434 patients treated by coil embolization without stenting, expressing packing density as volume embolization ratio (VER, volume of inserted coils/aneurysm volume). Six morphological variables (neck width, height, maximum diameter, dome to neck ratio (DNR), and aspect ratio), aneurysm location, and whether the aneurysm was ruptured or unruptured were analyzed with respect to dense (VER ≥20%) or loose (VER <20%) packing densities, using logistic regression analysis and ROC analysis. Among 452 aneurysms, VERs >20% were achieved for 272 aneurysms, with a mean VER of 24.7%. The mean VER of the remaining 180 aneurysms was 15.6%. In univariate analyses, the predictors for dense packing were having an anterior circulation, DNR, aspect ratio, and neck width. In multivariate analysis, the independent predictors were smaller neck width (odds ratio (OR) 0.8735; 95% confidence interval (CI) 0.7635-0.9993) and larger aspect ratio (OR 1.6679; 95% CI 1.0460-2.6594). ROC analysis showed optimal cutoff values for an aspect ratio of 1.35 (sensitivity 69.5%, specificity 51.7%) and a neck width of 3.13 mm (sensitivity 51.1%, specificity 27.8%). Although dense coil packing is still difficult to achieve in wide-necked aneurysms without the use of stents, packing with VER >20% is expected to be achieved when the height is 1.35 times larger than the neck width.

New York State: Comparison of Treatment Outcomes for Unruptured Cerebral Aneurysms Using an Instrumental Variable Analysis

Background

There is wide regional variation in the predominant treatment for unruptured cerebral aneurysms. We investigated the association of elective surgical clipping and endovascular coiling with mortality, readmission rate, length of stay, and discharge to rehabilitation.

Methods and Results

We performed a cohort study involving patients with unruptured cerebral aneurysms, who underwent surgical clipping or endovascular coiling from 2009 to 2013 and were registered in the Statewide Planning and Research Cooperative System database. An instrumental variable analysis was used to investigate the association of treatment technique with outcomes. Of the 4643 patients undergoing treatment, 3190 (68.7%) underwent coiling, and 1453 (31.3%) underwent clipping. Using an instrumental variable analysis, we did not identify a difference in inpatient mortality (marginal effect, 0.13; 95% CI, −0.30, 0.57), or the rate of 30-day readmission (marginal effect, −1.84; 95% CI −4.06, −0.37) between the 2 treatment techniques for patients with unruptured cerebral aneurysms. Clipping was associated with a higher rate of discharge to rehabilitation (marginal effect, 2.31; 95% CI 0.21, 4.41), and longer length of stay (β, 2.01; 95% CI 0.85, 3.04). In sensitivity analysis, mixed-effect regression, and propensity score, adjusted regression models demonstrated identical results.

Conclusions

Using a comprehensive all-payer cohort of patients in New York State with unruptured cerebral aneurysms, we did not identify an association of treatment method with mortality or 30-day readmission. Clipping was associated with a higher rate of discharge to rehabilitation and longer length of stay.

Clinical Risk Factors Affecting Procedure-Related Major Neurological Complications in Unruptured Intracranial Aneurysms

PURPOSE

The operative risk and natural history rupture risk for the treatment of unruptured intracranial aneurysms (UIAs) should be evaluated. The purpose of this study was to report our experience with treating UIAs and to outline clinical risk factors associated with procedure-related major neurological complications.

MATERIALS AND METHODS

We treated 1158 UIAs in 998 patients over the last 14 years. All patients underwent operation performed by a single microvascular surgeon and two interventionists at a single institution. Patient factors, aneurysm factors, and clinical outcomes were analyzed in relation to procedure-related complications.

RESULTS

The total complication rate was 22 (2.2%) out of 998 patients. Among them, complications developed in 14 (2.3%) out of 612 patients who underwent microsurgery and in 8 (2.1%) out of 386 patients who underwent endovascular procedures. One patient died due to intraoperative rupture during an endovascular procedure. The procedure-related complication was highly correlated with age (p=0.004), hypertension (p=0.002), and history of ischemic stroke (p<0.001) in univariate analysis. The multivariate analysis revealed previous history of ischemic stroke (p=0.001) to be strongly correlated with procedure-related complications.

CONCLUSION

A history of ischemic stroke was strongly correlated with procedure-related major neurological complications when treating UIAs. Accordingly, patients with UIAs who have a previous history of ischemic stroke might be at risk of procedure-related major neurological complications.