Kallmes, David F.

Background and Purpose— Maturing techniques have spurred widespread implementation of endovascular embolectomy therapy for ischemic stroke. We evaluated a large administrative database to determine outcomes in patients treated with endovascular embolectomy in the general population. Methods— Using the National Inpatient Sample, we evaluated outcomes of patients treated for acute ischemic stroke in the United States from 2006 to 2008. Patients who had an ischemic stroke and underwent endovascular clot retrieval were identified. Morbidity, defined as “discharge to long-term facility,” and mortality were evaluated as a function of patient age and of concomitant thrombolytic agent administration. Results— For 2006 to 2008, a total of 3864 patients received endovascular clot retrieval with 266 (6.9%) patients in 2006, 800 (20.7) patients in 2007, and 2798 (72.4%) patients in 2008. The discharge to a long-term facility rate was 51.3% (1983 of 3864). The in-hospital mortality rate was 24.3% (940 of 3864). For patients <65 years old, the rate of in-hospital death was 17.1% (283 of 1658) as compared with a rate of 29.7% (656 of 2206) for patients ≥65 years old ( P <0.0001). The rate of discharge to a long-term facility was 47.6% (789 of 1658) for patients <65 years old and 54.1% (1193 of 2206) for patients ≥65 years old ( P <0.0001). The rate of intracranial hemorrhage was 15.5% without concomitant thrombolysis and 20.0% with concomitant thrombolysis ( P =0.0009). Conclusions— Rates of morbidity and mortality remain high for patients with acute stroke, even in the setting of endovascular embolectomy. Advanced age portends a worse outcome and patients treated with concomitant use of thrombolytic agent had higher rates of intracranial hemorrhage than those without such therapy.

Background and Purpose— Age might differentially affect outcomes in patients treated for unruptured cerebral aneurysms with surgical clipping versus endovascular coil therapy. We evaluated a large administrative database to determine the effect of age on outcomes in patients treated for unruptured cerebral aneurysm. Methods— Using the National Inpatient Sample, we evaluated morbidity (discharge to long-term facility) and mortality of patients undergoing clipping or coiling of unruptured cerebral aneurysms in the United States between 2001 and 2008. Outcomes were evaluated in relation to four age strata: younger than 50 years; 50 to 64 years; 65 to 79 years; and patients 80 years or older. Results— Patients younger than 50 years old undergoing coiling had significantly lower morbidity rates when compared to patients who underwent clipping (3.5% versus 8.1%; P <0.0001), but no difference in mortality (0.6% versus 0.6%; P =0.72). Patients between 50 and 64 years old undergoing coiling had significantly decreased morbidity (4.0% versus 13.7%; P <0.0001) and mortality (0.5% versus 1.1%; P <0.0001) when compared to patients who underwent clipping. Coiled patients 65 to 79 years old had lower morbidity (6.9% versus 26.8%; P <0.0001) and mortality (0.8% versus 2.0%; P <0.0001) compared to patients who underwent clipping. Patients aged 80 years or older undergoing coiling also had lower morbidity (9.8% versus 33.5%; P <0.0001) and mortality (2.4% versus 21.4%; P <0.0001) when compared to patients who have undergone clipping. Conclusions— Patients treated with endovascular coiling have significantly less morbidity and mortality than those treated with surgical clipping, and these differences become more pronounced with age.

Computational fluid dynamics (CFD) studies provide a valuable tool for evaluating the role of hemodynamics in vascular diseases such as cerebral aneurysms and atherosclerosis. However, such models necessarily only include isolated segments of the vasculature. In this work, we evaluate the influence of geometric approximations in vascular anatomy on hemodynamics in elastase induced saccular aneurysms in rabbits. One representative high aspect ratio (AR—height/neck width) aneurysm and one low AR aneurysm were created at the origin of the right common carotid artery in two New Zealand white rabbits. Three-dimensional (3D) reconstructions of the aneurysm and surrounding arteries were created using 3D rotational angiographic data. Five models with varying extents of neighboring vasculature were created for both the high and low AR cases. A reference model included the aneurysm sac, left common carotid artery (LCCA), aortic arch, and downstream trifurcation/quadrification. Three-dimensional, pulsatile CFD studies were performed and streamlines, wall shear stress (WSS), oscillatory shear index, and cross sectional velocity were compared between the models. The influence of the vascular domain on intra-aneurysmal hemodynamics varied between the low and high AR cases. For the high AR case, even a simple model including only the aneurysm, a small section of neighboring vasculature, and simple extensions captured the main features of the steamline and WSS distribution predicted by the reference model. However, the WSS distribution in the low AR case was more strongly influenced by the extent of vasculature. In particular, it was necessary to include the downstream quadrification and upstream LCCA to obtain good predictions of WSS. The findings in this work demonstrate the accuracy of CFD results can be compromised if insufficient neighboring vessels are included in studies of hemodynamics in elastase induced rabbit aneurysms. Consideration of aspect ratio, hemodynamic parameters of interest, and acceptable magnitude of error when selecting the vascular domain will increase reliability of the results while decreasing computational time.

Background and Purpose— We performed a meta-analysis of published studies on the endovascular treatment of very small intracranial aneurysms, including 71 patients treated at our institution. Methods— We conducted a computerized MEDLINE search of the literature for reports on the treatment of intracranial aneurysms with a maximum dimension of ≤3 mm by using the search terms “small,” “tiny,” “intracranial aneurysm,” “endovascular,” and “coil.” A total of 7 studies, including our institution’s consecutive case series of 71 intracranial aneurysms, were included in this study. We extracted information regarding intraoperative complications, procedural mortality and morbidity, immediate- and long-term angiographic outcomes, and retreatment rate. The meta-analysis was performed with the statistical package Comprehensive Meta-Analysis. Results— Approximately 61% of the aneurysms in this meta-analysis presented as ruptured, whereas 39% of the aneurysms were unruptured. Procedural rupture rates for very small aneurysms was 8.3% (95% CI, 6.0% to 11.4%). The mortality rate due to procedural rupture was 2.4% (95% CI, 1.2% to 4.7%). The morbidity rate due to thromboembolic complications was 1.9% (95% CI, 0.9% to 3.9%). Subarachnoid hemorrhage within 1 month of treatment occurred in 1.6% (95% CI, 0.6% to 3.7%) of cases. There was no statistically significant difference between unruptured and ruptured aneurysms for any of these outcomes. Conclusion— Our meta-analysis suggests that treatment of very small aneurysms is feasible and effective in >90% of treated aneurysms. However, the risk of periprocedural rupture is higher than that reported for larger aneurysms. Similarly, the combined rate of periprocedural mortality and morbidity is not negligible (7.3%) and should be considered when considering the best therapeutic option for these aneurysms.

Background and Purpose— Predictive models of outcome after ischemic stroke have incorporated acute diffusion-weighted MRI (DWI) information with mixed results. We hypothesized that serial measurements of DWI infarct volume would be predictive of functional outcome after ischemic stroke. Methods— The prospective Acute Stroke Accurate Prediction (ASAP) Study included a prespecified serial imaging subgroup who underwent DWI studies at baseline (<24 hours after symptom onset) and Day 5 (±2 days). DWI infarct volumes were calculated using the Analyze software (Rochester, Minn). Clinical outcomes were assessed at 3 months. Univariate and multivariable regression analysis was performed to assess the relationship between change in DWI lesion volume and excellent neurological outcome (modified Rankin Scale 0, 1, and Barthel Index ≥95). Results— In total, 169 cases from the ASAP study had serial DWI scans with a measurable lesion at baseline, follow-up, or both. The median baseline National Institutes of Health Stroke Scale score was 6 (interquartile range, 3 to 13). For each 10 cm 3 of growth in DWI infarct volume, the OR for achieving an excellent outcome by modified Rankin Scale was 0.52 (95% CI, 0.38 to 0.71) and for the Barthel Index was 0.64 (95% CI, 0.51 to 0.79). Adjusting for clinically important covariates, the OR for an excellent modified Rankin Scale outcome was 0.57 (95% CI, 0.37 to 0.88) and excellent Barthel Index outcome was 0.75 (95% CI, 0.56 to 1.01). Conclusions— Based on these data, the likelihood of achieving an excellent neurological outcome diminishes substantially with growth in DWI infarct volume in the first 5 days after ischemic stroke of mild to moderate severity.

Object Approximately 20% of patients with an intracranial saccular aneurysm report a family history of intracranial aneurysm (IA) or subarachnoid hemorrhage. A better understanding of predictors of aneurysm detection in familial IA may allow more targeted aneurysm screening strategies. Methods The Familial Intracranial Aneurysm (FIA) study is a multicenter study, in which the primary objective is to define the susceptibility genes related to the formation of IA. First-degree relatives (FDRs) of those affected with IA are offered screening with magnetic resonance (MR) angiography if they were previously unaffected, are ≥ 30 years of age, and have a history of smoking and/or hypertension. Independent predictors of aneurysm detection on MR angiography were determined using the generalized estimating equation version of logistic regression. Results Among the first 303 patients screened with MR angiography, 58 (19.1%) had at least 1 IA, including 24% of women and 11.7% of men. Ten (17.2%) of 58 affected patients had multiple aneurysms. Independent predictors of aneurysm detection included female sex (odds ratio [OR] 2.46, p = 0.001), pack-years of cigarette smoking (OR 3.24 for 20 pack-years of cigarette smoking compared with never having smoked, p < 0.001), and duration of hypertension (OR 1.26 comparing those with 10 years of hypertension to those with no hypertension, p = 0.006). Conclusions In the FIA study, among the affected patients' FDRs who are > 30 years of age, those who are women or who have a history of smoking or hypertension are at increased risk of suffering an IA and should be strongly considered for screening.