Outcomes of endovascular mechanical thrombectomy and intravenous tissue plasminogen activator for the treatment of vertebrobasilar stroke

Background and Purpose

Aggressive treatment of posterior-circulation occlusions is important due to the high rates of morbidity and mortality associated with these infarctions. A large administrative database was evaluated to determine the outcomes of mechanical thrombectomy and intravenous tissue plasminogen activator (IV-tPA) for the treatment of posterior-circulation (vertebrobasilar) strokes. Outcomes were compared across age groups.

Methods

The United States Nationwide Inpatient Sample was used to evaluate the outcomes of patients treated for posterior-circulation acute ischemic stroke between 2006 and 2010. Patients who underwent endovascular mechanical thrombectomy and IV-tPA were selected. Primary outcomes were discharge status and mortality; secondary outcomes were length of stay, rate of intracranial hemorrhage, tracheostomy, and percutaneous endoscopic gastrostomy/jejunostomy tube placement. Outcomes were grouped according to age (i.e., <50, 50-64, and ≥65 years). Chi-squared test and Student's t-test were used for comparisons of categorical and continuous variables, respectively.

Results

During 2006-2010 there were 36,675 patients who had discharge International Classification of Diseases (9th edition) codes indicating posterior-circulation strokes. Of these, 631 (1.7%) underwent mechanical thrombectomy and 1554 (4.2%) underwent IV-tPA. The in-hospital mortality rate for mechanical thrombectomy patients was significantly lower for those aged <50 years than for those aged 50-64 years (30.4% versus 47.4%, p<0.01) and those aged ≥65 years (30.4% versus 43.0%, p≤0.01). Age had no effect on the in-hospital mortality for IV-tPA patients, with an incidence of 22.7% for patients aged <50 years, compared to 25.4% for patients aged 50-64 years (p=0.46) and 23.0% for patients aged ≥65 years (p=0.92).

Conclusions

Patients requiring IV-tPA and/or mechanical thrombectomy for the treatment of posterior-circulation strokes suffer from high mortality rates. Increased age is associated with significantly higher mortality rates among posterior-circulation stroke patients who require mechanical thrombectomy.

Treatment of cavernous sinus aneurysms with flow diversion: results in 44 patients

BACKGROUND AND PURPOSE

Aneurysms of the cavernous segment of the ICA are difficult to treat with standard endovascular techniques, and ICA sacrifice achieves a high rate of occlusion but carries an elevated level of surgical complications and risk of de novo aneurysm formation. We report rates of occlusion and treatment-related data in 44 patients with cavernous sinus aneurysms treated with flow diversion.

MATERIALS AND METHODS

Patients with cavernous segment aneurysms treated with flow diversion were selected from a prospectively maintained data base of patients from 2009 to the present. Demographic information, treatment indications, number/type of flow diverters placed, outcome, complications (technical or clinical), and clinical/imaging follow-up data were analyzed.

RESULTS

We identified 44 patients (37 females, 7 males) who had a flow diverter placed for treatment of a cavernous ICA aneurysm (mean age, 57.2; mean aneurysm size, 20.9 mm). The mean number of devices placed per patient was 2.2. At final angiographic follow-up (mean, 10.9 months), 71% had complete occlusion, and of those with incomplete occlusion, 40% had minimal remnants (<3 mm). In symptomatic patients, complete resolution or significant improvement in symptoms was noted in 90% at follow-up. Technical complications (which included, among others, vessel perforation in 4 patients, groin hematoma in 2, and asymptomatic carotid occlusion in 1) occurred in approximately 36% of patients but did not result in any clinical sequelae immediately or at follow-up.

CONCLUSIONS

Our series of flow-diversion treatments achieved markedly greater rates of complete occlusion than coiling, with a safety profile that compares favorably with that of carotid sacrifice.

Pretreatment advanced imaging in patients with stroke treated with IV thrombolysis: evaluation of a multihospital data base

BACKGROUND AND PURPOSE

CT angiography, CT perfusion, and MR imaging have all been advocated as potentially useful in treatment planning for patients with acute ischemic stroke. We evaluated a large multihospital data base to determine how the use of advanced imaging is evolving in patients treated with intravenous thrombolysis.

MATERIALS AND METHODS

Patients with acute ischemic stroke receiving IV thrombolytic therapy from 2008 to 2011 were identified by using the Premier Perspective data base. Mortality and discharge to long-term care rates were compared following multivariate logistic regression between patients who received head CT only versus those who received CTA without CT perfusion, CT perfusion, or MR imaging.

RESULTS

Of 12,429 included patients, 7305 (59%) were in the CT group, 2359 (19%) were in the CTA group, 848 (7%) were in the CTP group, and 1917 (15%) were in the MR group. From 2008 to 2011, the percentage of patients receiving head CT only decreased from 64% to 55%, while the percentage who received cerebral CT perfusion increased from 3% to 8%. The use of CT angiography and MR imaging marginally increased (1%-2%). Outcomes were similar between CT only and advanced imaging patients, except discharge to long-term care was slightly more frequent in the CTP group (OR = 1.17 [95% CI, 0.96-1.43]; P = .0412) and MR group (OR = 1.14 [95% CI, 1.01-1.28]; P = .0177) and mortality was lower in the MR group (OR = 0.64 [95% CI, 0.52-0.79]; P < .0001).

CONCLUSIONS

Use of advanced imaging is increasing in patients treated with IV thrombolysis. While there were differences in outcomes among imaging groups, the clinical effect of advanced imaging remains unclear.

Mechanisms of stroke after intracranial angioplasty and stenting in the SAMMPRIS trial

BACKGROUND

Enrollment in the stenting and aggressive medical management for the prevention of stroke in intracranial stenosis (SAMMPRIS) trial was halted owing to higher-than-expected 30-day stroke rates in the stenting arm. Improvement in periprocedural stroke rates from angioplasty and stenting for intracranial atherosclerotic disease (ICAD) requires an understanding of the mechanisms of these events.

OBJECTIVE

To identify the types and mechanisms of periprocedural stroke after angioplasty and stenting for ICAD.

METHODS

Patients who experienced a hemorrhagic or ischemic stroke or a cerebral infarct with temporary signs within 30 days of attempted angioplasty and stenting in SAMMPRIS were identified. Study records, including case report forms, procedure notes, and imaging were reviewed. Strokes were categorized as ischemic or hemorrhagic. Ischemic strokes were categorized as perforator territory, distal embolic, or delayed stent thrombosis. Hemorrhagic strokes were categorized as subarachnoid or intraparenchymal. Causes of hemorrhage (wire perforation, vessel rupture) were recorded.

RESULTS

Three patients had an ischemic stroke after diagnostic angiography. Two of these strokes were unrelated to the procedure. Twenty-one patients had an ischemic stroke (n = 19) or cerebral infarct with temporary signs (n = 2) within 30 days of angioplasty and stenting. Most (n = 15) were perforator territory and many of these occurred after angiographically successful angioplasty and stenting of the basilar artery (n = 8). Six patients experienced a subarachnoid hemorrhage (3 from wire perforation) and 7 had a delayed intraparenchymal hemorrhage.

CONCLUSION

Efforts at reducing complications from angioplasty and stenting for ICAD must focus on reducing the risks of regional perforator infarction, delayed intraparenchymal hemorrhage, and wire perforation.

Socioeconomic disparities in the utilization of mechanical thrombectomy for acute ischemic stroke

BACKGROUND

Previous studies have demonstrated that socioeconomic disparities in access to treatment of cerebrovascular diseases exist. We studied the Nationwide Inpatient Sample (NIS) to determine if disparities exist in utilization of mechanical thrombectomy for acute ischemic stroke.

METHODS

Using the NIS for the years 2006-2010, we selected all discharges with a primary diagnosis of acute ischemic stroke. Patients who received mechanical thrombectomy for stroke were identified by using the International Classification of Diseases, Ninth Revision, procedure code 39.74. We examined the utilization rates of mechanical thrombectomy by race/ethnicity (white, black, Hispanic, and Asian/Pacific Islander), income quartile (first, second to third, and fourth), and insurance status (Medicare, Medicaid, self-pay, and private). We also studied thrombectomy utilization rates at hospitals that performed thrombectomy.

RESULTS

From 2006 to 2010, 2,087,017 patients were hospitalized with a primary diagnosis of acute ischemic stroke; 8946 patients (.4%) received mechanical thrombectomy. Compared with white patients, black patients had significantly lower rates of overall mechanical thrombectomy utilization (odds ratio [OR] = .59, 95% confidence interval [CI] = .55-.64, P < .0001) and at centers that offered mechanical thrombectomy (OR = .44, 95% CI = .41-.47, P < .0001). Compared with patients in the highest income quartile, patients in the lowest income quartile had significantly lower rates of mechanical thrombectomy utilization both overall (OR = .66, 95% CI = .62-.70, P < .0001) and at centers that offered mechanical thrombectomy (OR = .80, 95% CI = .75-.84, P < .0001). Compared with patients with private insurance, self-pay patients had significantly lower mechanical thrombectomy utilization both overall (OR = .71, 95% CI = .64-.78, P < .0001) and at centers that offered mechanical thrombectomy (OR = .81, 95% CI = .74-.90, P < .0001).

CONCLUSIONS

Significant socioeconomic disparities exist in the utilization of mechanical thrombectomy in the United States.

Use of CT angiography and digital subtraction angiography in patients with ruptured cerebral aneurysm: evaluation of a large multihospital data base

BACKGROUND AND PURPOSE

Both CT angiography and digital subtraction angiography are used to detect aneurysms in patients with subarachnoid hemorrhage. We examined a large multihospital data base to determine how practice is evolving with regard to the use of CT angiography and DSA in patients with ruptured cerebral aneurysm.

MATERIALS AND METHODS

The Premier Perspective data base was used to identify hospitalizations of patients treated with clipping or coiling of ruptured cerebral aneurysms from 2006-2011. Billing information was used to determine pretreatment and posttreatment use of DSA and CT angiography during hospitalization.

RESULTS

A total of 4972 patients (1022 clipping, 3950 coiling) at 116 hospitals were identified. The percentage of patients with SAH who underwent pretreatment CT angiography significantly increased from 20% in 2006 to 44% in 2011 (P < .0001), whereas the percentage of patients who underwent DSA remained unchanged from 96-94% (P = .28). This CT angiography trend was observed in coiling patients (17-42%, P < .0001) and clipping patients (32-54%, P < .0001). There was a significant increase in the percentage of patients who underwent posttreatment imaging from 41% in 2006 to 48% in 2011 (P = .0037). This trend was observed in clipping patients (33-65%, P < .0001) but not coiling patients (43-45%, P = .62).

CONCLUSIONS

For the pretreatment evaluation of ruptured aneurysms, the use of CT angiography increased from 2006-2011 without a corresponding decrease in the use of DSA. These results raise the question of potential redundancy without added clinical value of the second test.

Socioeconomic disparities in the utilization of mechanical thrombectomy for acute ischemic stroke in US hospitals

BACKGROUND AND PURPOSE

Previous studies have demonstrated that socioeconomic disparities in the treatment of cerebrovascular diseases exist. We studied a large administrative data base to study disparities in the utilization of mechanical thrombectomy for acute ischemic stroke.

MATERIALS AND METHODS

With the utilization of the Perspective data base, we studied disparities in mechanical thrombectomy utilization between patient race and insurance status in 1) all patients presenting with acute ischemic stroke and 2) patients presenting with acute ischemic stroke at centers that performed mechanical thrombectomy. We examined utilization rates of mechanical thrombectomy by race/ethnicity (white, black, and Hispanic) and insurance status (Medicare, Medicaid, self-pay, and private). Multivariate logistic regression analysis adjusting for potential confounding variables was performed to study the association between race/insurance status and mechanical thrombectomy utilization.

RESULTS

The overall mechanical thrombectomy utilization rate was 0.15% (371/249,336); utilization rate at centers that performed mechanical thrombectomy was 1.0% (371/35,376). In the sample of all patients with acute ischemic stroke, multivariate logistic regression analysis demonstrated that uninsured patients had significantly lower odds of mechanical thrombectomy utilization compared with privately insured patients (OR = 0.52, 95% CI = 0.25-0.95, P = .03), as did Medicare patients (OR = 0.53, 95% CI = 0.41-0.70, P < .0001). Blacks had significantly lower odds of mechanical thrombectomy utilization compared with whites (OR = 0.35, 95% CI = 0.23-0.51, P < .0001). When considering only patients treated at centers performing mechanical thrombectomy, multivariate logistic regression analysis demonstrated that insurance was not associated with significant disparities in mechanical thrombectomy utilization; however, black patients had significantly lower odds of mechanical thrombectomy utilization compared with whites (OR = 0.41, 95% CI = 0.27-0.60, P < .0001).

CONCLUSIONS

Significant socioeconomic disparities exist in the utilization of mechanical thrombectomy in the United States.

Acute branch occlusion after Pipeline embolization of intracranial aneurysms

Flow-diverters are used in the treatment of large and complex intracranial aneurysms. One major concern with this concept is the potential for compromise of side branches and perforators covered by the device. We describe three patients treated with the Pipeline embolization device (PED; ev3 Endovascular, Plymouth, MN, USA) who developed immediate compromise of flow into an eloquent side branch covered by the device. Three patients, two with giant posterior circulation aneurysms and one with recurrence of a previously clipped and subsequently coiled middle cerebral artery aneurysm, were each treated by placement of a single PED. Shortly after placement of the devices, despite adequate antiplatelet and anticoagulation regimens, partial or complete occlusion of a major side branch occurred. In all three patients, the occlusion was promptly reversed with intra-arterial administration of abciximab with no clinical sequelae. These cases are concerning because branch occlusion occurred even in the setting of patients appropriately premedicated with dual antiplatelet therapy and in whom genetic testing suggested clopidogrel responsiveness. Close monitoring of patients treated with these devices is critical to establish the frequency of this and other unanticipated complications.

Comparative effectiveness of ruptured cerebral aneurysm therapies: propensity score analysis of clipping versus coiling

BACKGROUND AND PURPOSE

The relative merits of treating ruptured aneurysms with clipping versus coiling continue to be a topic of debate. We evaluated a national, multihospital patient data base to examine recent trends in ruptured aneurysm therapies and to compare peri-procedural outcomes between clipping and coiling treatments.

MATERIALS AND METHODS

The Premier Perspective data base was used to identify patients hospitalized between 2006-2011 for ruptured aneurysm who underwent clipping or coiling therapy. A propensity score model, representing the probability of receiving clipping, was generated for each patient by use of relevant patient and hospital variables. After Greedy-type matching of the propensity score, the risk of in-hospital mortality and morbidity was compared between clipping and coiling cohorts.

RESULTS

A total of 5229 patients with ruptured aneurysm (1228 clipping, 4001 coiling) treated at 125 hospitals were identified. Clipping therapy frequency decreased from 27% in 2006 to 21% in 2011. After propensity score adjustment, in-hospital mortality risk was similar between groups (OR = 0.94 [95% CI, 0.73-1.21]; P = .62). However, unfavorable outcomes were more common after clipping compared with coiling, including discharge to long-term care (OR = 1.32 [95% CI, 1.12-1.56]; P = .0006), ischemic complications (OR = 1.51 [95% CI, 1.24-1.83]; P = .0009), neurologic complications (OR = 1.64 [95% CI, 1.18-2.27]; P = .0018), and other surgical complications (OR = 1.55 [95% CI, 1.05-2.33]; P = .0240).

CONCLUSIONS

This study of a data base of multiple hospitals in the United States demonstrates that clipping of ruptured cerebral aneurysms resulted in greater adjusted morbidity compared with coiling.

Endovascular treatment of distal anterior cerebral artery aneurysms: single-center experience and a systematic review

In this study, a single center's experience of 20 patients and a systematic review and a meta-analysis of 16 studies, including 279 patients/aneurysms, assessed the safety and efficacy of endovascular treatment of distal anterior cerebral artery aneurysms. The authors conclude that endovascular treatment of distal anterior cerebral artery aneurysms is associated with high angiographic occlusion rates, but the complication rates are higher compared with other aneurysms in the circle of Willis.

Protamine does not increase risk of stroke in patients with elective carotid stenting

BACKGROUND AND PURPOSE

Reversal of anticoagulation with protamine might predispose to a higher risk of stroke in patients with carotid stenting. We evaluated a national, multihospital patient database to examine the risk of stroke in patients with carotid stenting receiving protamine compared with those who did not.

METHODS

The Premier Perspective database was used to identify patients who were electively hospitalized for carotid stenting from 2006 through 2011. The incidence of in-hospital mortality and morbidity was compared between patients who did and did not receive protamine after propensity score adjustment via 1:1 matching to reduce selection bias.

RESULTS

Of 6664 patients with carotid stenting treated at 193 hospitals, 556 (8%) received protamine on the day of the procedure. After matching by propensity score, patients who received protamine had a similar likelihood of stroke or transient ischemic attack (P=0.77), in-hospital mortality (P=0.12), discharge to long-term care (P=0.15), and access site complications (P=0.90) as compared with patients who did not receive protamine.

CONCLUSIONS

Protamine administration is not associated with additional risk of adverse events after carotid stenting.

Are routine intensive care admissions needed after endovascular treatment of unruptured aneurysms?

SUMMARY

Routine intensive care unit monitoring is common after elective embolization of unruptured intracranial aneurysms. In this series of 200 consecutive endovascular procedures for unruptured intracranial aneurysms, 65% of patients were triaged to routine (non-intensive care unit) floor care based on intraoperative findings, aneurysm morphology, and absence of major co-morbidities. Only 1 patient (0.5%) required subsequent transfer to the intensive care unit for management of a perioperative complication. The authors conclude that patients without major co-morbidities, intraoperative complications, or complex aneurysm morphology can be safely observed in a regular ward rather than being admitted to the intensive care unit.

Rescue treatment of thromboembolic complications during endovascular treatment of cerebral aneurysms

BACKGROUND AND PURPOSE

Acute intraprocedural thrombus formation complicating endovascular cerebral aneurysm treatment is often treated with intra-arterial or intravenous administration of thrombolytic agents or glycoprotein IIb/IIIa (GpIIb/IIIa) inhibitors. We sought to evaluate the morbidity and mortality associated with such treatments using a large multihospital database.

METHODS

Using the Premier Perspective Database, we examined outcomes for patients receiving endovascular coiling for ruptured and unruptured aneurysms requiring rescue therapy, defined as treatment with GpIIb/IIIa inhibitors and fibrinolytic therapy. We compared discharge status, length of stay, and complication rates across 3 groups: (1) patients receiving GpIIb/IIIa inhibitors only, (2) patients receiving fibrinolytic therapy only, and (3) patients receiving both GpIIb/IIIa inhibitors and fibrinolytics. Student t test was used to compare continuous variables, and Fisher exact test was used to compare categorical variables.

RESULTS

Seven-percent (254/3627) of patients treated for unruptured aneurysms received rescue therapy. When compared with patients receiving GpIIb/IIIa inhibitors alone, patients receiving only fibrinolytics had significantly higher rates of discharge to institutions other than home (37.5% [9/24] versus 7.4% [15/201]; P<0.0001). Eight-percent of patients (338/4204) treated for ruptured aneurysms received rescue therapy. When compared with patients receiving GpIIb/IIIa inhibitors alone, patients receiving only fibrinolytics had significantly higher rates of mortality (26.0% [18/69] versus 14.5% [35/241]; P=0.02) and discharge to institutions other than home (59.4% [41/69] versus 36.5% [88/241]; P<0.0001).

CONCLUSIONS

Pharmacological rescue therapy occurred in 7% to 8% of endovascular coiling patients with unruptured and ruptured intracranial aneurysms. Rescue therapy with thrombolytic agents resulted in significantly more morbidity and mortality than rescue therapy with GpIIb/IIIa inhibitors.

Comparative Effectiveness of Unruptured Cerebral Aneurysm Therapies

Background and Purpose—

Endovascular therapy has increasingly become the most common treatment for unruptured cerebral aneurysms in the United States. We evaluated a national, multi-hospital database to examine recent utilization trends and compare periprocedural outcomes between clipping and coiling treatments of unruptured aneurysms.

Methods—

The Premier Perspective database was used to identify patients hospitalized between 2006 to 2011 for unruptured cerebral aneurysm who underwent clipping or coiling therapy. A logistic propensity score was generated for each patient using relevant patient, procedure, and hospital variables, representing the probability of receiving clipping. Covariate balance was assessed using conditional logistic regression. Following propensity score adjustment using 1:1 matching methods, the risk of in-hospital mortality and morbidity was compared between clipping and coiling cohorts.

Results—

A total of 4899 unruptured aneurysm patients (1388 clipping, 3551 coiling) treated at 120 hospitals were identified. Following propensity score adjustment, clipping patients had a similar likelihood of in-hospital mortality (odds ratio [OR], 1.43; 95% confidence interval [CI], 0.49–4.44; P =0.47) but a significantly higher likelihood of unfavorable outcomes, including discharge to long-term care (OR, 4.78; 95% CI, 3.51–6.58; P <0.0001), ischemic complications (OR, 3.42; 95% CI, 2.39–4.99; P <0.0001), hemorrhagic complications (OR, 2.16; 95% CI, 1.33–3.57; P <0.0001), postoperative neurological complications (OR, 3.39; 95% CI, 2.25–5.22; P <0.0001), and ventriculostomy (OR, 2.10; 95% CI, 1.01–4.61; P =0.0320) compared with coiling patients.

Conclusions—

Among patients treated for unruptured intracranial aneurysms in a large sample of hospitals in the United States, clipping was associated with similar mortality risk but significantly higher periprocedural morbidity risk compared with coiling.

Review of 2 decades of aneurysm-recurrence literature, part 2: Managing recurrence after endovascular coiling

Cerebral aneurysms are treated to prevent hemorrhage or rehemorrhage. Angiographic recurrences following endovascular therapy have been a problem since the advent of this treatment technique, even though posttreatment hemorrhage remains rare. Notwithstanding its unclear clinical significance, angiographic recurrence remains not only a prime focus in the literature but also frequently leads to potentially risky retreatments. The literature regarding aneurysm recurrence following endovascular therapy, spanning 2 decades, is immense and immensely confusing. We review the topic of recurrence following endovascular treatment of cerebral aneurysms in an effort to distill it down to fundamental material relevant to clinical practice.

Clarifying differences among thrombolysis in cerebral infarction scale variants: is the artery half open or half closed?

BACKGROUND AND PURPOSE

Although thrombolysis in cerebral infarction (TICI) 2b/3 has been regarded as a successful angiographic outcome, the definition or subclassification of TICI 2 has differed between the original (o-TICI) and modified TICI (m-TICI). We sought to compare interobserver variability for both scores and analyze the subgroups of the TICI 2.

METHODS

Five readers interpreted angiographies independently using a 6-point scale as follows: grade 0, no antegrade flow; grade 1, flow past the initial occlusion without tissue reperfusion; grade 2, partial reperfusion in <50% of the affected territory; grade 3, partial reperfusion in 50% to 66%; grade 4, partial reperfusion in ≥ 67%; grade 5, complete perfusion. Readings using this scale were then converted into o-TICI and m-TICI score. Statistical analysis was performed according to TICI 2 subgroups.

RESULTS

Interobserver agreement was good for the o-TICI and m-TICI scores (intraclass correlation coefficient, 0.73 and 0.67, respectively). Our grade 3 (partial perfusion with 50% to 66%) occupied 19% of total readings, which would have been classified as grade 2a in o-TICI, but as 2b in m-TICI. The m-TICI was more likely to predict good clinical outcome than o-TICI (odds ratio, 2.01 versus 1.63, in reads with TICI 2b/3 versus 0/2a).

CONCLUSIONS

Both TICI scales showed good agreement among readers. However, the variability in partial perfusion thresholds leads to different grading in ≈ 20% of cases and may result in significantly different rates of accurate outcome prediction.

Abstract 156: SAMMPRIS Angiography Discloses Hemodynamic Effects of Intracranial Stenosis: Computational Fluid Dynamics of Fractional Flow

Background: Pressure gradients across an intracranial stenosis, or fractional flow (FF), may identify the hemodynamic significance of symptomatic lesions. Computational fluid dynamic (CFD) simulations on 3D morphology of such lesions can calculate these pressure gradients and model effects of systemic physiology interacting with these lesions, such as hypotension and induced hypertension. We studied SAMMPRIS angiography to calculate FF across symptomatic intracranial stenoses and modeled the downstream effect of systemic blood pressure (BP) fluctuations.

Methods: Conventional angiography of symptomatic intracranial stenoses in the SAMMPRIS trial was converted from biplanar images to a 3D geometric mesh. CFD simulations were conducted with Ansys CFX on a Cray supercomputer to calculate FF derived from distal/proximal pressure gradients for each of 3 inflow conditions: normal BP (120/80 mm Hg), hypotension (90/60 mm Hg) and hypertension (180/120 mm Hg). Abnormal FF was defined as ≤ 0.8 during diastole to define hemodynamic significance of a stenosis.

Results: 407 patients with 70-99% symptomatic stenosis had conventional angiography with biplanar views available for 3D reconstruction in 249, and CFD simulations in 188 (25 VA, 45 BA, 32 ICA, 86 MCA). Under simulated normal inflow conditions (120/80 mm Hg), only 76/188 (40%) cases had low FF.

During simulated hypertension, FF improved to normal in 10/188 (5%) cases. Simulated hypotension caused FF to worsen from normal in 12/188 (6%) cases. Other hemodynamic parameters including shear stress could also be calculated and visually depicted in all cases.

Conclusions: CFD and hemodynamic modeling of FF can be retrospectively performed after 3D conversion of biplanar angiogram views. FF estimates predict that only 40% of severe (70-99%) symptomatic intracranial stenoses are hemodynamically significant. Systemic BP fluctuations can be modeled during phases of the cardiac cycle to show downstream flow changes.

Review of 2 decades of aneurysm-recurrence literature, part 1: reducing recurrence after endovascular coiling

SUMMARY

Angiographic recurrence following endovascular therapy is an indirect measure of the potential for hemorrhage. Because patients and physicians consider recurrence to be a suboptimal outcome with some chance of future hemorrhage, much effort has been expended to reduce the incidence of recurrence. The literature regarding aneurysm recurrence following endovascular therapy, spanning 2 decades, is extensive. We will review and summarize the effort to reduce recurrence following endovascular treatment of cerebral aneurysms.

Endovascular treatment of intracranial aneurysms with flow diverters: a meta-analysis

BACKGROUND AND PURPOSE

Flow diverters are important tools in the treatment of intracranial aneurysms. However, their impact on aneurysmal occlusion rates, morbidity, mortality, and complication rates is not fully examined.

METHODS

We conducted a systematic review of the literature searching multiple databases for reports on the treatment of intracranial aneurysms with flow-diverter devices. Random effects meta-analysis was used to pool outcomes of aneurysmal occlusion rates at 6 months, and procedure-related morbidity, mortality, and complications across studies.

RESULTS

A total of 29 studies were included in this analysis, including 1451 patients with 1654 aneurysms. Aneurysmal complete occlusion rate was 76% (95% confidence interval [CI], 70%-81%). Procedure-related morbidity and mortality were 5% (95% CI, 4%-7%) and 4% (95% CI, 3%-6%), respectively. The rate of postoperative subarachnoid hemorrhage was 3% (95% CI, 2%-4%). Intraparenchymal hemorrhage rate was 3% (95% CI, 2%-4%). Perforator infarction rate was 3% (95% CI, 1%-5%), with significantly lower odds of perforator infarction among patients with anterior circulation aneurysms compared with those with posterior circulation aneurysms (odds ratio, 0.01; 95% CI, 0.00-0.08; P<0.0001). Ischemic stroke rate was 6% (95% CI, 4%-9%), with significantly lower odds of perforator infarction among patients with anterior circulation aneurysms compared with those with posterior circulation aneurysms (odds ratio, 0.15; 95% CI, 0.08-0.27; P<0.0001).

CONCLUSIONS

This meta-analysis suggests that treatment of intracranial aneurysms with flow-diverter devices is feasible and effective with high complete occlusion rates. However, the risk of procedure-related morbidity and mortality is not negligible. Patients with posterior circulation aneurysms are at higher risk of ischemic stroke, particularly perforator infarction. These findings should be considered when considering the best therapeutic option for intracranial aneurysms.

Interobserver agreement after pipeline embolization device implantation

BACKGROUND AND PURPOSE

Although flow diversion devices are popular in treatment of aneurysms, angiographic assessment with these devices has rarely been verified by interobserver variability study. The purpose of this study was to determine the interobserver agreement of a 3-point grading system for assessing the angiographic outcome after flow diversion therapy of intracranial, saccular aneurysms and to determine factors affecting such agreement.

MATERIALS AND METHODS

After approval by the institutional review board, 5 independent readers assessed pretreatment and follow-up digital subtraction angiograms from 96 patients treated with the Pipeline embolization device by using a 3-point grading system (complete, near-complete, and incomplete occlusion). "Minor discrepancy" was defined as a difference between any 2 readers of 1 grade, that is, complete vs near-complete or near-complete vs incomplete. "Major discrepancy" was defined as a difference between any 2 readers in which 1 reader noted complete occlusion and the other reader noted incomplete occlusion. We performed statistical analysis for the interobserver agreement by using the intraclass correlation coefficient. Subgroup analyses for discrepancy rate and ICC were performed for previously coiled aneurysms.

RESULTS

The interobserver agreement was excellent (ICC, 0.76; 95% CI, 0.69-0.92). Among 96 cases, there was absolute agreement in 74 (77%), of which 67 had unanimous consensus of "complete" occlusion, 2 "near-complete" occlusion, and 5 "incomplete" occlusion. Discordance between any 2 readers was noted in 22 cases (23%), of which 7 (7.3%) revealed a major discrepancy. Subgroup analysis showed that minor discrepancies were more common among patients previously treated with coils vs those not previously treated with coils (37.5% vs 11.2%; P < .05).

CONCLUSIONS

The observer agreement regarding occlusion after PED therapy is excellent. Only a minority of cases demonstrated discrepancy considered as major in this study.

Efficacy and safety of flow diversion for paraclinoid aneurysms: a matched-pair analysis compared with standard endovascular approaches

BACKGROUND AND PURPOSE

Flow diversion is a new strategy for the treatment of complex paraclinoid aneurysms. However, flow diverters have, to date, not been tested in direct comparison with other available treatments. We present a matched-pair comparison of paraclinoid aneurysms treated with the PED versus other endovascular techniques.

MATERIALS AND METHODS

Twenty-one eligible patients with 22 paraclinoid aneurysms treated with the PED at our institution were matched with historic controls with aneurysms of similar size and location.

RESULTS

There were no statistically significant differences between the 2 groups in terms of aneurysm size, location, risk factors, or comorbidities. Mean dome size was 13.9 ± 6.7 mm in the control group and 14.9 ± 6.3 mm in the PED group (P = .52). Balloon and stent assistance were used in 31.8% and 9.1% of controls, respectively, while carotid sacrifice was used in 36.4% of the controls. There was a significant difference in the rate of complete occlusion favoring PED at radiologic follow-up (P = .03).

CONCLUSIONS

Flow diverters achieve a much higher rate of complete angiographic obliteration compared with other standard endovascular techniques in the treatment of internal carotid artery aneurysms. In this series, this higher angiographic obliteration rate did not occur at the expense of an increased rate of complications. Careful long-term follow-up is of the utmost importance to definitively validate flow diversion as a superior therapeutic strategy for proximal internal carotid artery aneurysms.

Age-related trends in the treatment and outcomes of ruptured cerebral aneurysms: a study of the nationwide inpatient sample 2001-2009

BACKGROUND AND PURPOSE

Patient age substantially influences treatment decisions for ruptured cerebral aneurysms. It would be useful to understand national age-related trends of treatment techniques and outcomes in patients treated for ruptured cerebral aneurysm in the United States.

MATERIALS AND METHODS

Using the US Nationwide Inpatient Sample, we evaluated trends in treatment technique (clipping versus coiling) and discharge status of patients undergoing clipping or coiling of ruptured cerebral aneurysms between 2001 and 2009. Outcomes were evaluated in relation to 4 age strata: 1) younger than 50 years of age, 2) 50-64 years of age, 3) 65-79 years of age, and 4) patients 80 years or older. We compared outcomes between treatment groups for patients treated between 2001-2004 with those treated between 2005-2009.

RESULTS

A significant increase in the proportion of patients undergoing endovascular coiling between 2001 and 2009 was noted for all age groups (P < .0001). For both clipped and coiled patients, mortality and the proportion of patients discharged to long-term facilities increased with age. Overall mortality for patients clipped and coiled decreased modestly for all age groups, and overall proportions of patients discharged home increased modestly (P < .01) for all age groups except those older than 80 years of age.

CONCLUSIONS

Between 2001 and 2009, there has been a significant increase in the proportion of patients with ruptured aneurysms undergoing endovascular coiling rather than aneurysm clipping. This increase was more pronounced in older patients. Mortality from aneurysmal subarachnoid hemorrhage decreased during the past decade, regardless of aneurysm treatment technique.

Interobserver variability in retreatment decisions of recurrent and residual aneurysms

BACKGROUND AND PURPOSE

The degree of variation in retreatment decisions for residual or recurrent aneurysms among endovascular therapists remains poorly defined. We performed a multireader study to determine what reader and patient variables contribute to this variation.

MATERIALS AND METHODS

Seven endovascular therapists (4 neuroradiologists, 3 neurosurgeons) independently reviewed 66 cases of patients treated with endovascular coil embolization for ruptured or unruptured aneurysm. Cases were rated on a 5-point scale recommending for whether to retreat and a recommended retreatment type. Reader agreement was assessed by intraclass correlation coefficient and by identifying cases with a "clinically meaningful difference" (a difference in score that would result in a difference in treatment). Variables that affect reader agreement and retreatment decisions were examined by using the Wilcoxon signed-rank test, Pearson χ(2) test, and linear regression.

RESULTS

Overall interobserver variability for decision to retreat was moderate (ICC = 0.50; 95% CI, 0.40-0.61). Clinically meaningful differences between at least 2 readers were present in 61% of cases and were significantly more common among neuroradiologists than neurosurgeons (P = .0007). Neurosurgeons were more likely to recommend "definitely retreat" than neuroradiologists (P < .0001). Previously ruptured aneurysms, larger remnant size, and younger patients were associated with more retreat recommendations. Interobserver variability regarding retreatment type was fair overall 0.25 (95% CI, 0.14-0.41) but poor for experienced readers 0.14 (95% CI, 0-0.34).

CONCLUSIONS

There is a large amount of interobserver variability regarding the decision to retreat an aneurysm and the type of retreatment. This variability must be reduced to increase consistency in these subjective outcome measurements.

Detailed analysis of periprocedural strokes in patients undergoing intracranial stenting in Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS)

BACKGROUND AND PURPOSE

Enrollment in the Stenting and Aggressive Medical Management for Preventing Recurrent stroke in Intracranial Stenosis (SAMMPRIS) trial was halted due to the high risk of stroke or death within 30 days of enrollment in the percutaneous transluminal angioplasty and stenting arm relative to the medical arm. This analysis focuses on the patient and procedural factors that may have been associated with periprocedural cerebrovascular events in the trial.

METHODS

Bivariate and multivariate analyses were performed to evaluate whether patient and procedural variables were associated with cerebral ischemic or hemorrhagic events occurring within 30 days of enrollment (termed periprocedural) in the percutaneous transluminal angioplasty and stenting arm.

RESULTS

Of 224 patients randomized to percutaneous transluminal angioplasty and stenting, 213 underwent angioplasty alone (n=5) or with stenting (n=208). Of these, 13 had hemorrhagic strokes (7 parenchymal, 6 subarachnoid), 19 had ischemic stroke, and 2 had cerebral infarcts with temporary signs within the periprocedural period. Ischemic events were categorized as perforator occlusions (13), embolic (4), mixed perforator and embolic (2), and delayed stent occlusion (2). Multivariate analyses showed that higher percent stenosis, lower modified Rankin score, and clopidogrel load associated with an activated clotting time above the target range were associated (P ≤ 0.05) with hemorrhagic stroke. Nonsmoking, basilar artery stenosis, diabetes, and older age were associated (P ≤ 0.05) with ischemic events.

CONCLUSIONS

Periprocedural strokes in SAMMPRIS had multiple causes with the most common being perforator occlusion. Although risk factors for periprocedural strokes could be identified, excluding patients with these features from undergoing percutaneous transluminal angioplasty and stenting to lower the procedural risk would limit percutaneous transluminal angioplasty and stenting to a small subset of patients. Moreover, given the small number of events, the present data should be used for hypothesis generation rather than to guide patient selection in clinical practice. Clinical Trial Registration Information- URL: http://clinicaltrials.gov. Unique Identifier: NCT00576693.

Coiling for paraclinoid aneurysms: time to make way for flow diverters?

BACKGROUND AND PURPOSE

Paraclinoid aneurysms represent challenging lesions for which endovascular techniques have gained widespread application in their treatment. A new endovascular strategy, flow diversion, is gaining importance in the treatment of these aneurysms. Before embracing flow diversion in larger numbers of patients with paraclinoid aneurysms, it is important to know the safety and efficacy of "traditional" endovascular methods for these aneurysms. We review complications and outcomes of patients with unruptured paraclinoid aneurysms treated with coils, with or without balloon and stent assistance, over the past 12 years at our institution.

MATERIALS AND METHODS

A retrospective review of 118 patients with 126 unruptured paraclinoid aneurysms, treated between 1999 and 2010, was performed. Clinical records, endovascular reports, angiographic results, and clinical outcomes were reviewed and analyzed.

RESULTS

Fifty-nine percent of aneurysms were carotid-ophthalmic, 27% were hypophyseal, 9% were posterior carotid wall, 3% were carotid cave, and 2% were transitional. Twenty-one percent of aneurysms were symptomatic, and 3% were recurrent aneurysms after previous treatment. Fifty (40%) were treated with balloon assistance and 18 (14%) with stent assistance. Technical complications causing permanent morbidity occurred in 1 patient (0.8%), while early clinical complications causing transient morbidity occurred in 5 (4%) patients. Complete occlusion was achieved in 40% of aneurysms immediately after treatment and in 66 (62%) aneurysms during follow-up (mean 31.9 ± 28.4 months). Recurrences occurred in 18 patients (17%) and 10 (9%) patients were retreated. Clinical outcome was good in 95% and poor in 5% of the 107 patients with follow-up (mean 37.0 ± 33.7 months). Only in 1 patient was poor outcome related to the endovascular procedure. Transient ischemic attacks occurred in 4% of patients. No cases of rebleeding were observed during follow-up.

CONCLUSIONS

Modern endovascular coil treatment of unruptured paraclinoid aneurysms appears safe, with satisfactory, although not ideal, rates of complete occlusion. The introduction of flow diverters will probably increase the rate of complete angiographic occlusion, but this must be achieved with low complication rates.

Small (< 10-mm) incidentally found intracranial aneurysms, Part 2: treatment recommendations, natural history, complications, and short-term outcome in 212 consecutive patients

OBJECT

The management of incidental small unruptured intracranial aneurysms (UIAs) is controversial and many factors need to be considered in the decision-making process. The authors describe a large consecutive series of patients harboring small incidental intracranial aneurysms. Treatment strategy, natural history, complications, and short-term outcomes are presented.

METHODS

Between January 2008 and May 2011, the authors prospectively evaluated 212 patients with 272 small (< 10-mm) incidental aneurysms. Treatment recommendations (observation, endovascular treatment, or surgery), complications of treatment, and short-term outcomes were assessed.

RESULTS

Recommended treatment consisted of observation in 125 patients, endovascular embolization in 64, and surgery in 18. Six patients were excluded from further analysis because they underwent treatment elsewhere. In the observation group, at a mean follow-up of 16.7 months, only 1 patient was moved to the embolization group. Seven (6%) of the 125 patients in the observation group died of causes unrelated to aneurysm. Sixty-five patients underwent 69 embolization procedures. The periprocedural permanent morbidity and mortality rates in patients undergoing endovascular treatment were 1.5% and 1.5%, respectively (overall morbidity and mortality rate 3.0%). In the surgery group no periprocedural complications were observed, although 1 patient did not return to her previous occupation. No aneurysmal rupture was documented in any of the 3 treatment groups during the follow-up period.

CONCLUSIONS

A cautious and individualized approach to incidental UIAs is of utmost importance for formulation of a safe and effective treatment algorithm. Invasive treatment (either endovascular or surgery) can be considered in selected younger patients, certain "higher-risk" locations, expanding aneurysms, patients with a family history of aneurysmal hemorrhage, and in those who cannot live their lives knowing that they harbor the UIA. Although the complication rate of invasive treatment is very low, it is not negligible. The study confirms that small incidental UIAs deemed to be not in need of treatment have a very benign short-term natural history, which makes observation a reasonable approach in selected patients.

Curative Onyx embolization of tentorial dural arteriovenous fistulas

OBJECT

The authors conducted a study to review their experience with tentorial dural arteriovenous fistulas (DAVFs) treated with transarterial endovascular embolization in which Onyx was used.

METHODS

The authors reviewed prospectively collected data in 9 patients with tentorial DAVFs treated with Onyx embolization between 2008 and 2011. Information reviewed included clinical presentation, angiographic features, treatment, and clinical and radiologically documented outcome. Clinical follow-up was available in every patient. Radiological follow-up studies were available in 8 of 9 patients (mean follow-up 4.6 months).

RESULTS

Six of 9 patients had complete angiographic obliteration (in 5 this was confirmed by a follow-up angiogram obtained 3-6 months later), and 2 patients had near-complete obliteration (faint filling of the venous drainage in the late venous phase). One patient had partial obliteration and required surgical disconnection. In all patients with complete obliteration, transarterial embolization was performed through the posterior branch of the middle meningeal artery. There were no procedural complications, and no morbidity or mortality resulted from Onyx embolization.

CONCLUSIONS

Transarterial Onyx embolization is a valid, effective, and safe alternative to surgical disconnection in many patients with tentorial DAVFs. The presence of an adequate posterior branch of the middle meningeal artery is critical to achieve a microcatheter position distal enough to increase the likelihood of complete obliteration.

Utilization of intravenous thrombolysis is increasing in the United States

BACKGROUND

Evaluating recombinant tissue plasminogen activator utilization rates is important, as many studies have demonstrated that administration of recombinant tissue plasminogen activator to qualified patients significantly improves prognosis.

AIMS

We investigated recent trends in the utilization and outcomes of administration of intravenous recombinant tissue plasminogen activator in the United States using the National Inpatient Sample between 2001 and 2008.

METHODS

We identified patients with a primary diagnosis of acute ischemic stroke who underwent treatment with intravenous recombinant tissue plasminogen activator and studied utilization rates and clinical outcomes: discharge to long-term facility (morbidity), in-hospital death (mortality), and intracranial hemorrhage. Information on demographics, hospital characteristics, and comorbidities was collected. A multivariate logistic regression analysis was performed to determine independent predictors of morbidity, mortality, and intracranial hemorrhage.

RESULTS

Intravenous recombinant tissue plasminogen activator utilization increased from 1·3% in 2001 to 3·5% in 2008. On multivariate analysis, variables associated with increased morbidity after intravenous recombinant tissue plasminogen activator administration included advanced age (P < 0·001), female gender (P < 0·001), and comorbidities of atrial fibrillation (P < 0·001) and hypertension (P < 0·001). Increased mortality was associated with increased age (P < 0·001) and comorbidities of atrial fibrillation, congestive heart failure, coronary artery disease, and diabetes (P < 0·001 for all comorbidities).

CONCLUSIONS

Intravenous recombinant tissue plasminogen activator utilization rates increased between 2001 and 2008. Advanced age and atrial fibrillation were significantly associated with increased morbidity and mortality among patients treated with intravenous recombinant tissue plasminogen activator.

Post–Cardiac Arrest Mortality Is Declining

Background—

Despite several advances in postresuscitation care over the past decade, population-based mortality rates for patients hospitalized with cardiac arrest in the United States have not been studied over this time period. The aim of this study was to determine the annual in-hospital mortality rates of patients with cardiac arrest from 2001 to 2009.

Methods and Results—

The US mortality rates for hospitalized patients with cardiac arrest were determined using the 2001 to 2009 US National Inpatient Sample, a national hospital discharge database. Using the International Classification of Diseases , 9 th Edition, code 427.5, we identified patients hospitalized in the United States with cardiac arrest from 2001 to 2009. The main outcome measure was in-hospital mortality. A total of 1 190 860 patients were hospitalized with a diagnosis of cardiac arrest in the United States from 2001 to 2009. The in-hospital mortality rate decreased each year from 69.6% in 2001 to 57.8% in 2009. In multivariable analysis, when controlling for age, sex, race, and comorbidities, earlier year was a strong independent predictor of in-hospital death. The mortality rate declined across all analyzed subgroups, including sex, age, race, and stratification by comorbidity.

Conclusions—

The in-hospital mortality rate of patients hospitalized with cardiac arrest in the United States decreased by 11.8% from 2001 to 2009.

Hospitalization costs for endovascular and surgical treatment of ruptured aneurysms in the United States are substantially higher than Medicare payments

BACKGROUND AND PURPOSE

Endovascular and surgical options are both available for treatment of ruptured cerebral aneurysms. Knowledge of the costs relative to Medicare reimbursement for hospitalization of these patients is important for understanding the economic impact of these patients on hospitals.

MATERIALS AND METHODS

Using the NIS, we identified hospitalizations for clipping and coiling of ruptured cerebral aneurysms from 2001 to 2008 by cross-matching ICD-9 codes for diagnosis of ruptured aneurysm with procedure codes for clipping or coiling of cerebral aneurysms. Hospital costs for 2008 were correlated with age, sex, and discharge status. For discharges of Medicare patients, we compared Medicare payments with costs for respective MS-DRG.

RESULTS

For 2008, the average Medicare payment for craniotomy and endovascular intracranial procedures without complication (MS-DRG 22) was $30,380. Medicare discharges with DRG 22, for patients undergoing clipping had median costs of $59,799 in 2008. Those undergoing coiling had median costs of $36,543. Reimbursement for discharges with complications or comorbidities (MS-DRG 21) was $36,304. Median costs for hospitalization of clipped patients with MS DRG 21 was $79,916 and for coiled patients, $56,910. Reimbursement for MS-DRG 20 (major complications or comorbidities) was $41,748, with patients undergoing clipping incurring a median cost of $83,737 and those undergoing coiling incurring a median cost of $83,277.

CONCLUSIONS

Hospitalization costs for patients undergoing clipping and coiling of unruptured cerebral aneurysms are substantially higher than Medicare payments.

Subarachnoid hemorrhage incidence in the United States does not vary with season or temperature

BACKGROUND AND PURPOSE

Previous studies have suggested seasonal variations in rates of spontaneous rupture of intracranial aneurysms, leading to potentially devastating SAH. In an effort to identify a seasonal effect, variation in SAH incidence and in-hospital mortality rates were examined as they relate to admission month, temperature, and climate using HCUP's Nationwide Inpatient Sample.

MATERIALS AND METHODS

Cases of nontraumatic SAH and subsequent in-hospital mortality were extracted from the 2001-2008 NIS and associated with month of occurrence, local average monthly temperatures, and USDA climate zone. Multivariate regression analysis was used to study how admission month, temperature, and climate affected SAH admission and mortality rates.

RESULTS

Among 57,663,486 hospital admissions from the 2001-2008 NIS, 52,379 cases of spontaneous SAH (ICD-9-CM 430) and 13,272 cases of subsequent in-hospital mortality were identified. SAH incidence and in-hospital mortality rates were not significantly correlated with a monthly/seasonal effect (incidence, χ(2) = 2.94, P = .99; mortality, χ(2) = 6.91, P = .81). However, SAH incidence significantly varied with climate (P < .0001, zones 11 and 7) but not with temperature (P = .1453), whereas average monthly temperature and climate had no significant correlation with in-hospital mortality (temperature, P = .3005; climate, P = .0863).

CONCLUSIONS

We identified no significant monthly or temperature-related effect in the incidence of SAH. Our data suggest that certain climate zones within the United States may be associated with significantly different SAH incidence, but the origins of these differences remain unclear and are probably unrelated to meteorologic variables.

Comparison of hospitalization costs and Medicare payments for carotid endarterectomy and carotid stenting in asymptomatic patients

BACKGROUND AND PURPOSE

Hospitals struggle to provide care for elderly patients based on Medicare payments. Amid concerns of inadequate reimbursement, we sought to evaluate the hospitalization costs for recipients of CEA and CAS placement, identify variables associated with increased costs, and compare these costs with Medicare reimbursements.

MATERIALS AND METHODS

All CEA and CAS procedures were extracted from the 2001-2008 NIS. Average CMS reimbursement rates for CEA and CAS were obtained from www.CMS.gov. Annual trends in hospital costs were analyzed by Sen slope analysis. Associations between LOS and hospital costs with respect to sex, age, discharge status, complication type, and comorbidity were analyzed by using the Wilcoxon rank sum test. Least-squares regression models were used to predict which variables had the greatest impact on LOS and hospital costs.

RESULTS

The 2001-2008 NIS contained 181,200 CEA and 12,485 CAS procedures. Age and sex were not predictive of costs for either procedure. Among favorable outcomes, CAS was associated with significantly higher costs compared with CEA (P < .0001). Average Medicare payments were $1,318 less than costs for CEA and $3,241 less than costs for CAS among favorable outcomes. Greater payment-to-cost disparities were noted for both CEA and CAS in patients who had unfavorable outcomes.

CONCLUSIONS

The 2008 Medicare hospitalization payments were substantially less than median hospital costs for both CAS and CEA. Efforts to decrease hospitalization costs and/or increase payments will be necessary to make these carotid revascularization procedures economically viable for hospitals in the long term.

Fulminant postpartum cerebral vasoconstriction syndrome

OBJECTIVE

To raise awareness of the potentially adverse consequences of postpartum cerebral vasoconstriction, which is typically considered benign and self-limiting, by describing 4 fulminantly fatal cases.

DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Four postpartum women aged 15 to 33 years developed acute neurologic deficits 1 to 8 days after uncomplicated deliveries. One had a history of migraine headaches and 2 had histories of spontaneous abortion. Two of the patients had uneventful pregnancies and 2 had preeclampsia, 1 of whom had acute hepatic failure. Presenting symptoms included severe headache (n=3), focal deficit (n=1), seizure (n=1), and encephalopathy (n=1). Initial brain imaging results demonstrated cortical ischemia and global edema in 2 patients, lobar hemorrhage in 1, and normal findings in 1. All had rapid clinical deterioration from hours to days with multiterritorial infarctions and global brain edema on imaging. All had angiographic findings of diffuse, severe, segmental multifocal arterial narrowings.

INTERVENTIONS

Aggressive treatment was attempted with most patients including intravenous magnesium sulfate, corticosteroids, calcium channel blockers, balloon angioplasty, vasopressors, and osmotic agents. Two patients underwent serial angiography, with results showing severe, recurrent proximal vasoconstriction involving all major intracranial vessels.

RESULTS

All patients had fulminant, accelerating courses leading to their deaths within 8 to 24 days after delivery.

CONCLUSIONS

Postpartum vasoconstriction can be fatal, with rapid progression of vasoconstriction, ischemia, and brain edema. Clinicians need to be aware of the potential consequences of this condition. Postpartum women with acute neurologic symptoms require prompt investigation with noninvasive cerebrovascular imaging and close monitoring for possible secondary deterioration.

Abstract 3155: Hospitalization Costs for Acute Ischemic Stroke Patients Treated with Intravenous Thrombolysis in the United States are Substantially Higher than Medicare Payments

Background and Purpose- IV rt-PA has become a widely accepted treatment for a select group of patients with acute ischemic stroke. Quantifying the costs of hospitalization is important for understanding the economic impact of these patients on the hospitals that care for them. We evaluated recent data to determine costs associated with hospitalization for acute ischemic stroke patients treated with intravenous thrombolysis, including subgroup analysis to determine the effects of age and discharge status on hospital costs.

Methods- Using the National Inpatient Sample, we evaluated the costs for hospitalization for patients treated with intravenous thrombolysis for acute ischemic stroke in the United States from 2001-2008. The primary endpoint examined in this study was total hospital costs, and these were correlated with clinical outcome. Costs were compared with 2008 Medicare reimbursement for intravenous thrombolysis without complication, and intravenous thrombolysis with major complication.

Results- A total of 63472 patients received intravenous thrombolysis for acute ischemic stroke. 24094 patients were <65 years old and 40780 patients were ≥65 years old. Median hospital costs in 2008 dollars were $14102 (IQR $9987-$20819) for patients with good outcome, $18856 (IQR $13145-$30423) for patients with severe disability, and $19129 (IQR $11966-$30781) for patients with mortality. Average 2008 Medicare payments were $10,098 for intravenous thrombolysis without complication and $13,835 for intravenous thrombolysis with major complication.

Conclusions- Our study of the NIS shows that hospitalization costs in the United States for ischemic stroke patients treated with intravenous thrombolysis are rather high. Medicare payments have not been adequate reimbursement for these hospitalizations. Hopefully, future reconciliation of costs with payments will be feasible, so that hospitals can afford to provide proper care for ischemic stroke patients treated with intravenous thrombolysis.

Abstract 1900: Collateral Circulation and Hemodynamics of Severe Intracranial Atherosclerosis: Angiography and Clinical Correlates at Baseline in the SAMMPRIS Trial

Background: Severe intracranial atherosclerosis, in excess of 70% luminal stenosis, is an established cause of recurrent stroke. Collateral circulation and the hemodynamic effects of such stenoses, however, may further delineate such risk. We conducted angiographic analyses in the SAMMPRIS trial to correlate the degree of collaterals and hemodynamic effects of such stenoses with baseline clinical and imaging characteristics of enrolled subjects.

Methods: Baseline angiography of SAMMPRIS subjects was submitted for blinded review to grade collaterals with the ASITN/SIR scale and antegrade flow across the lesion with TICI. Hemodynamic effect was defined as any flow reduction (a partial TICI score). The association of these angiographic scores (dichotomized as none/partial versus complete collaterals and partial versus complete TICI) and baseline demographic, clinical and imaging variables were evaluated using chi-square tests for percentages and independent group t-tests for means.

Results: 424/451 subjects enrolled in SAMMPRIS had baseline angiography available for review, with adequate information to score collaterals in 376 cases. Complete collaterals were noted in 117 (31%). Hemodynamic effects (partial TICI scores) were noted in only 188 (50%) of these lesions, which were all in excess of 70% luminal stenosis. Mean lesion length (n=184, from stenting arm) did not differ between the two categories of either collaterals or hemodynamic impairment. Mean percent stenosis was higher for patients with complete collaterals (none/partial, mean 73.7%; complete, 77.4%; p<0.001) and hemodynamic impairment was more common (p<0.001). More robust collaterals (complete versus none/partial) were associated with patients who at baseline were younger (mean age 58.0 versus 61.5 years; p=0.009), had higher serum HDL (40.0 versus 37.7 mg /dL, p=0.035), participated in moderate exercise (43.1 versus 27.9%, p=0.004) and did not smoke (79.5 versus 69.4%, p=0.042). Previously reported associations with collateral circulation (diabetes, statins, presence of infarction on CT or MRI) were inapparent. These relationships of collaterals with hemodynamic impairment and other baseline variables were established across all anatomical distributions of intracranial stenosis.

Conclusions: Severe intracranial atherosclerotic lesions are not always associated with hemodynamic effects. Collateral circulation may also frequently compensate for severe stenosis, with more robust collaterals in younger and healthier individuals.

Abstract 3138: Hospitalization Costs for Acute Ischemic Stroke Patients Treated with Endovascular Embolectomy in the United States

Background and Purpose- It is important to know the costs for hospitalization for endovascular embolectomy patients so that comparisons can be made to payments to hospitals.

Methods- Using the National Inpatient Sample, we evaluated the costs for hospitalization for patients treated with endovascular embolectomy in the United States from 2006-2008. The primary endpoint examined in this study was total hospital costs, and these were correlated with clinical outcome. Hospitalization costs were then compared with Medicare payments for their respective outcomes. MS-DRG 24 was the diagnostic related group code (DRG) for mechanical embolectomy with good outcome and MS-DRG 23 was the DRG code for mechanical embolectomy with major complications. Medicare payments were available at http://www.cms.hhs.gov .

Results- A total of 3864 patients received endovascular embolectomy. 1649 patients were <65 years old and 2205 patients were ≥65 years old. Median hospital costs in 2008 dollars were $36,999 (IQR $26,662-$56,405) for patients with good outcome, $50,628 (IQR $33,135-$76,063) for patients with severe disability, and $35,109 (IQR $25,053-$62,621) for patients with mortality. Reimbursement in the year 2008 for DRG 24 (good outcome) was $22075 and reimbursement for DRG 23 (major complications) was $26639.

Conclusions- Our study of the NIS shows that hospitalization costs in the United States for ischemic stroke patients treated with endovascular embolectomy are rather high, probably due to the serious nature of their illness. Medicare payments have not been adequate in reimbursing these hospitalizations. Further work is needed to ensure the future reconciliation of costs with payments.

Abstract 3755: Flow Diversion for Proximal Internal Carotid Artery Aneurysms: Complications and Early Angiographic Results

Background: Flow diversion has been proposed as a valid option for patients with proximal internal carotid artery aneurysms. We analyzed a consecutive series of 38 patients with proximal (to the origin of the posterior communicating artery) internal carotid artery aneurysms treated with flow diversion over a 28-month interval.

Methods: Clinical information and angiographic follow-up data were prospectively collected in a consecutive series of patients with proximal internal carotid artery aneurysms treated with flow diversion. No patients were lost to follow-up and every eligible patient (with at least 6 months of follow-up) underwent catheter angiography at 6 months.

Results: The series include 38 patients (37 women and 1 man). Most of the aneurysms were large or giant and with a wide neck. In two patients, we failed to deliver the device to the target segment because of proximal vessel tortuosity; thus 36 patients underwent flow diversion. There were no permanent periprocedural neurological deficits. One patient experienced a transient neurological deficit and another patient suffered slight transient worsening of a third nerve paresis. Complete angiographic occlusion of the aneurysm was observed in 75% of patients at 6 months and in 87% of the eligible patients at one year. One patient was found to have asymptomatic internal carotid occlusion.

Conclusion: Flow diversion is an effective and safe method to treat internal carotid artery aneurysms not amenable to other endovascular techniques.

Abstract 124: Collaterals Determine Risk of Early Territorial Stroke and Hemorrhage in the SAMMPRIS Trial

Background: The degree of collateral circulation is a powerful risk factor for recurrent stroke in the setting of medical therapy for symptomatic intracranial atherosclerosis. The impact of collaterals on the short-term risk for stroke in patients treated by stenting or intensive medical therapies is not known. We systematically evaluated baseline angiographic features of collateral circulation and antegrade flow across intracranial stenoses in randomized subjects of the multicenter SAMMPRIS trial and correlated these to their 30-day risk of ischemic stroke.

Methods: Digital review of baseline angiograms in SAMMPRIS was conducted to score ASITN/SIR collateral grade and TICI antegrade flow, blind to other data. Dichotomized collateral and TICI scores (none/partial versus complete) were analyzed independently and in combinations with trial endpoints of territorial ischemic stroke or stroke in territory (SIT) and intracranial hemorrhage (ICH) within 30 days in the intensive medical and stenting arms of the study. Log-rank tests with follow-up time censored at 30 days were used in the analysis.

Results: Collaterals could be assessed on 376/424 baseline angiography studies available for digital imaging review for the 451 randomized subjects in SAMMPRIS (186 medical, 190 stenting). Early territorial stroke (SIT) occurred in 6/186 (3.2%) subjects in the medical arm and 20/190 (10.5%) after stenting. SIT was not associated with TICI in either arm, whereas collaterals exerted a potent protective influence in medical (p=0.067) and stented (p=0.004) cases, with 0/66 (0%) SIT in the medical arm and 0/51 (0%) SIT in the stented arm when collaterals were complete. SIT in medical cases was associated with partial TICI/partial collaterals (5/25 (20.0%)) versus complete TICI/partial collaterals (1/95 (1.1%)) and partial TICI/complete collaterals (0/66 (0%)), p<0.001. SIT in stented cases was associated with partial TICI/partial collaterals (11/46 (23.9%)) versus complete TICI/partial collaterals (9/93 (9.7%)) and partial TICI/complete collaterals (0/51 (0%)), p<0.001. ICH within 30 days occurred in 0/186 (0%) subjects randomized to medical therapy. In the stenting arm, early ICH occurred in 8/190 (4.2%) and was associated with TICI (p=0.036) and collaterals (p=0.077). Overall, early ICH after stenting was associated with partial TICI/partial collaterals (7/46 (15.2%)) versus complete TICI/partial collaterals (1/93 (1.1%)) and partial TICI/complete collaterals (0/51 (0%)), p<0.001.

Conclusions: Patients with impaired collateral flow associated with severe intracranial stenosis had the highest risk for stroke within 30 days, both with intensive medical therapy and as a complication of angioplasty and stenting.

Patency of the ophthalmic artery after flow diversion treatment of paraclinoid aneurysms

OBJECT

In this study the authors determined the patency rate of the ophthalmic artery (OphA) after placement of 1 or more flow diversion devices across the arterial inlet for treatment of proximal internal carotid artery (ICA) aneurysms, and correlated possible risk factors for OphA occlusion.

METHODS

Nineteen consecutive patients were identified (mean age 53.9 years, range 23-74 years, all female) who were treated for 20 ICA aneurysms. In all patients a Pipeline Embolization Device (PED) was placed across the ostium of the OphA while treating the target aneurysm. Flow through the OphA after PED placement was determined by immediate angiography as well as follow-up angiograms (mean 8.7 months), compared with the baseline study. Potential risk factors for OphA occlusion, including age, immediate angiographic flow through the ophthalmic branch, status of flow within the aneurysm after placement of PEDs, whether the ophthalmic branch originated from the aneurysm dome, and number of PEDs placed across the ophthalmic branch inlet were correlated with patency rate.

RESULTS

Patients were treated with 1-3 PEDs (3 aneurysms treated with placement of 1 PED, 12 with 2 PEDs, and 5 with 3 PEDs). In 17 (85%) of 20 treated aneurysms, no changes in the OphA flow were noted immediately after placement of the device. Two (10%) of 20 patients had delayed antegrade filling immediately following PED placement and 1 patient (5%) had retrograde flow from collaterals to the OphA immediately after placement of the device. One patient (5%) experienced delayed asymptomatic ICA occlusion; this patient was excluded from analysis at follow-up. At follow-up the OphA remained patent with normal antegrade flow in 13 (68%) of 19 patients, patent but with slow antegrade flow in 2 patients (11%), and was occluded in 4 patients (21%). No visual changes or clinical symptoms developed in patients with OphA flow compromise. The mean number of PEDs in the patients with occluded OphAs or change in flow at angiographic follow-up was 2.4 (SEM 0.2) compared with 1.9 (SEM 0.18) in the patients with no change in OphA flow (p = 0.09). There was no significant difference between the patients with occluded OphAs compared with nonoccluded branches based on patient age, immediate angiographic flow through the ophthalmic branch, status of flow through the aneurysm after placement of PEDs, whether the ophthalmic branch originated from the aneurysm dome, or number of PEDs placed across the ophthalmic branch inlet.

CONCLUSIONS

Approximately one-quarter of OphAs will undergo proximal thrombosis when covered with flow diversion devices. Even though these events were well-tolerated clinically, our findings suggest that coverage of branch arteries that have adequate collateral circulation may lead to spontaneous occlusion of those branches.