3631

Background and Purpose—The Solitaire With the Intention for Thrombectomy (SWIFT) and thrombectomy revascularization of large vessel occlusions in acute ischemic stroke (TREVO 2) trial results demonstrated improved recanalization rates with mechanical thrombectomy; however, outcomes in the elderly population remain poorly understood. Here, we report the effect of age on clinical and angiographic outcome within the North American Solitaire-FR Stent-Retriever Acute Stroke (NASA) Registry.

Methods—The NASA Registry recruited sites to submit data on consecutive patients treated with Solitaire-FR. Influence of age on clinical and angiographic outcomes was assessed by dichotomizing the cohort into ≤80 and >80 years of age.

Results—Three hundred fifty-four patients underwent treatment in 24 centers; 276 patients were ≤80 years and 78 were >80 years of age. Mean age in the ≤80 and >80 cohorts was 62.2±13.2 and 85.2±3.8 years, respectively. Of patients >80 years, 27.3% had a 90-day modified Rankin Score ≤2 versus 45.4% ≤80 years (P=0.02). Mortality was 43.9% and 27.3% in the >80 and ≤80 years cohorts, respectively (P=0.01). There was no significant difference in time to revascularization, revascularization success, or symptomatic intracranial hemorrhage between the groups. Multivariate analysis showed age >80 years as an independent predictor of poor clinical outcome and mortality. Within the >80 cohort, National Institutes of Health Stroke Scale (NIHSS), revascularization rate, rescue therapy use, and symptomatic intracranial hemorrhage were independent predictors of mortality.

Conclusion—Greater than 80 years of age is predictive of poor clinical outcome and increased mortality compared with younger patients in the NASA registry. However, intravenous tissue-type plasminogen activator use, lower NIHSS, and shorter revascularization time are associated with better outcomes. Further studies are needed to understand the endovascular therapy role in this cohort compared with medical therapy. (Stroke. 2014;45:3631-3636.)

Key Words: age groups ◼ aged ◼ stroke ◼ thrombectomy

Influence of Age on Clinical and Revascularization Outcomes in the North American Solitaire

Stent-Retriever Acute Stroke RegistryAlicia C. Castonguay, PhD; Osama O. Zaidat, MD, MS; Roberta Novakovic, MD;

Thanh N. Nguyen, MD; M. Asif Taqi, MD; Rishi Gupta, MD; Chung-Huan J. Sun, MD; Coleman Martin, MD; William E. Holloway, MD; Nils Mueller-Kronast, MD; Joey E. English, MD;

Italo Linfante, MD; Guilherme Dabus, MD; Tim W. Malisch, MD; Franklin A. Marden, MD; Hormozd Bozorgchami, MD; Andrew Xavier, MD; Ansaar T. Rai, MD;

Michael T. Froehler, MD, PhD; Aamir Badruddin, MD; Michael G. Abraham, MD; Vallabh Janardhan, MD; Hashem Shaltoni, MD; Albert J. Yoo, MD; Alex Abou-Chebl, MD;

Peng R. Chen, MD; Gavin W. Britz, MD; Ritesh Kaushal, MD; Ashish Nanda, MD; Mohammad A. Issa, MD; Raul G. Nogueira, MD

Received June 19, 2014; final revision received September 8, 2014; accepted September 25, 2014.From the Departments of Neurology (A.C.C., O.O.Z., M.A.I.), Neurosurgery (O.O.Z.), and Radiology (O.O.Z.), Medical College of Wisconsin/Froedtert

Hospital, Milwaukee, WI; Departments of Radiology and Neurology, UT Southwestern Medical Center, Dallas, TX (R.N.); Departments of Neurology, Neurosurgery, and Radiology, Boston Medical Center, Boston, MA (T.N.N.); Desert Regional Medical Center, Palm Springs, CA (M.A.T.); Wellstar Neurosurgery Kennestone Hospital, Atlanta, GA (R.G.); Department of Neurology, Emory University School of Medicine, Atlanta, GA (C.-H.J.S., R.G.N.); Saint Luke’s Kansas City, Kansas City, MO (C.M., W.E.H.); Department of Neurology, Delray Medical Center, Delray Beach, FL (N.M.-K.); California Pacific Medical Center, San Francisco, CA (J.E.E.); Division of Interventional Neuroradiology, Baptist Cardiac and Vascular Institute, Miami, FL (I.L., G.D.); Alexian Brothers Medical Center, Elk Grove Village, IL (T.W.M., F.A.M.); Oregon Health and Science University, Portland, OR (H.B.); Department of Neurology, Wayne State University School of Medicine, Detroit, MI (A.X.); Department of Radiology, West Virginia University Hospital, Morgantown, WV (A.T.R.); Departments of Neurology, Neurosurgery, and Radiology, Vanderbilt University Medical Center, Nashville, TN (M.T.F.); Provena Saint Joseph Medical Center, Joliet, IL (A.B.); University of Kansas Medical Center, Kansas City, KS (M.G.A.); Texas Stroke Institute, Plano, TX (V.J., A.A.-C.); University of Texas Health Science Center, Houston, TX (H.S.); Department of Radiology, Division of Diagnostic and Interventional Neuroradiology, Massachusetts General Hospital, Boston, MA (A.J.Y.); University of Texas, Houston, TX (P.R.C.); Department of Neurosurgery, Methodist Neurological Institute, Houston, TX (G.W.B.); Saint Louis University, St. Louis, MO (R.K.); and University of Missouri, Columbia, MO (A.N.).

The online-only Data Supplement is available with this article at http://stroke.ahajournals.org/lookup/suppl/doi:10.1161/STROKEAHA. 114.006487/-/DC1.

Correspondence to Osama O. Zaidat, MD, MS, Department of Neurology, Radiology, and Neurosurgery, Neurointerventional Division, Medical College of Wisconsin/Froedtert Hospital, Milwaukee, WI 53226. E-mail szaidat@mcw.edu

© 2014 American Heart Association, Inc.

Stroke is available at http://stroke.ahajournals.org DOI: 10.1161/STROKEAHA.114.006487

by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from

3632 Stroke December 2014

Mechanical thrombectomy using emerging stent-retriever technology has shown increasing promise as an effec-

tive treatment for acute ischemic stroke (AIS). The results of the Trevo versus Merci retrievers for thrombectomy revascu-larization of large vessel occlusions in AIS (TREVO 2) and the Solitaire With the Intention for Thrombectomy (SWIFT) clinical trials demonstrated superior revascularization rates and clinical outcomes compared with the first-generation Merci retriever device.1,2 Although the data from the SWIFT and TREVO 2 trials support the use of new-generation stent retrievers for the treatment of AIS, the safety and effective-ness of these devices have not been evaluated in the elderly population.

Several studies have previously examined the use of mechanical thrombectomy in octogenarians and have reported lower rates of good clinical outcome and higher rates of mor-tality in this age group.3–5 However, these initial studies were limited by their small patient size and inclusion of first-gener-ation retrieval devices. Because the elderly population, which carries a higher incidence of stroke, is expected to nearly dou-ble over the next several decades,6,7 it is critical to investigate the benefit of newer treatments and to understand potential characteristics within this population, which may influence clinical outcome following endovascular therapy (ET).

The aim of this substudy was to examine the influence of age on clinical and revascularization outcomes within the North American Solitaire Acute (NASA) Stroke Registry,8 a multicenter postmarketing registry reporting the real world clinical use of a newer generation stent retriever for the treat-ment of AIS.

MethodsThe investigator-initiated multicenter NASA Registry recruited 24 US sites to submit retrospective demographic, clinical presentation, site-adjudicated angiographic, procedural, and clinical outcome data on consecutive AIS patients treated with the Solitaire-FR device from March 2012 to February 2013.8–10 All patients participating in the NASA registry received Solitaire-FR as the first-choice device to re-store blood flow. Each site obtained local institutional review board approval for the study.

For the purpose of this substudy, the NASA cohort was dichoto-mized into 2 age groups based on previous studies3–5: patients ≤80 years of age and those >80 years old. Thrombolysis in Myocardial Ischemia (TIMI) and Treatment in Cerebral Ischemia (TICI) revascu-larization grades were defined according to the SWIFT and TREVO 2 trial definitions, respectively.1,2 Clinical outcomes were 90-day modi-fied Rankin Score (mRS), mortality, and symptomatic intracranial hemorrhage (sICH). Good clinical outcome was defined as a 90-day mRS≤2. sICH was defined as any parenchymal hematoma, subarach-noid hemorrhage, or intraventricular hemorrhage associated with a worsening of the National Institutes of Health Stroke Scale (NIHSS) by ≥4 within 24 hours. Interventional procedures and patient selec-tion were performed according to the standards and protocols at each site. Angiographic and clinical outcome data were adjudicated by each site. This study was performed without funding or industry sponsorship.

Statistical AnalysisThe data were stored and analyzed by the coordinating site, the Medical College of Wisconsin. Statistical analyses were performed using JMP 11 software (SAS Institute, Cary, NC). The NASA co-hort was dichotomized into patients ≤80 years of age and those >80 years old. Univariate analysis comparing the baseline characteristics

between the 2 groups was performed using the Student t test for con-tinuous variables and χ2 or Fisher exact test (when small cell sample size of a given variable existed) for binary variables. Variables with a P value of <0.10, and clinically relevant factors, were entered into a multivariate stepwise logistic regression model to determine predic-tors of clinical outcome and mortality.

ResultsNASA Full CohortThere were 354 patients from 24 US centers enrolled in the NASA Registry.8 The mean age for the total NASA cohort was 67.3±15.2 years (range, 20–100 years). For patients with good clinical outcome (mRS≤2), the mean age was 65±15.1 versus 69.2±15.1 years in those with a poor outcome (P=0.01).

NASA ≤80 Years and >80 Years Cohorts

Baseline CharacteristicsWhen dichotomizing the NASA cohort, 276 of 354 (78.0%) were ≤80 years (mean, 62.2±13.2) and 78 of 354 (22.0%) were >80 years of age (mean, 85.3±3.8). Baseline characteristics for the 2 cohorts are presented in Table 1. There was a greater percentage of women in the >80 years of age group than that in the ≤80 years cohort (65.4% versus 46.2%; P=0.003). The >80 years cohort had a greater prevalence of hyperten-sion (P=0.003), atrial fibrillation (P≤0.0001), hyperlipidemia (P=0.02), and coronary artery disease (P=0.004). There was no difference in the mean presenting NIHSS (P=0.2), base-line mRS≤2 (P=0.3), or prevalence of diabetes mellitus (0.8) in the 2 cohorts. In the ≤80 years cohort, a greater propor-tion of patients presented with internal carotid artery terminus (25.1%) and basilar occlusions (12.4%) compared with 16.7% and 2.6% in those patients >80 years old, respectively. No difference in the proportion of patients receiving intravenous tissue-type plasminogen activator (IV-tPA; P=0.4) was noted between the groups.

Procedural and Angiographic CharacteristicsNo difference in mean time from onset to groin puncture (364.7±228.5 minutes versus 358.9±272.9 minutes; P=0.9) or time to revascularization (71.7±89.5 minutes versus 93.1±114.5 minutes; P=0.08) was observed among the ≤80 or >80 groups, respectively (Table 2). With regard to revascu-larization, there was no difference in TIMI ≥2 (84.0% versus 83.3%; P=0.9) or TICI ≥2b (73.1% versus 69.2%; P=0.5) in the ≤80 or >80 years groups. The number of passes, use of a balloon guide catheter, and use of rescue therapy were simi-lar among the cohorts; however, the use of general anesthesia (73.0% versus 60.0%; P=0.05) was greater in the ≤80-year-old group and use of intra-arterial (IA)-tPA (25.4% versus 38.5%; P=0.02) was greater in those >80 years of age. Distal embolization and embolization into new territory was compa-rable in both cohorts (Table 2).

Clinical Outcome DataNinety-day mRS was reported in 249 of 276 (90.2%) and 66 of 78 (84.6%) patients ≤80 years and >80 years of age, respec-tively. On the univariate analysis, those >80 years demon-strated a lower rate of good clinical outcome (27.3% versus 45.4%; P=0.02) and increased mortality (43.9% versus 27.3%;

by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from

Castonguay et al Influence of Age in the NASA Registry 3633

P=0.01) at 90 days compared with those in the ≤80 years age group (Figure). Stratification by age showed that patients >80 years had poorer outcomes when compared with other age strata (Figure I in the online-only Data Supplement). No differ-ence was seen in the rate of sICH (9.1% versus 12.8%; P=0.4) in the ≤80 years and >80 years cohorts, respectively (Table 2).

Predictors of Clinical Outcome and MortalityAge >80 years remained as an independent predictor of poor clinical outcome and mortality when adjusting for dichoto-mized age (>80 years), sex, hypertension, atrial fibrillation, hyperlipidemia, smoking, coronary artery disease, general anesthesia, and IA-tPA use on the multivariate analysis (Table 3).

Greater Than 80 Years CohortTo evaluate the characteristics within the >80 years of age cohort that may contribute to clinical outcome and mortality, the >80 years population was dichotomized by 90-day clinical outcome (good versus poor) and mortality (Table I and II in the online-only Data Supplement). The multivariate analysis

(adjusting for time to revascularization, use of rescue therapy, number of passes, revascularization success [TICI ≥2b], ini-tial NIHSS, and IV-tPA use) showed initial NIHSS, time to revascularization, and IV-tPA use as independent predictors of clinical outcome in the >80 cohort (Table 4). Adjusting for initial NIHSS, hypertension, coronary artery disease, use of rescue therapy, TICI success (≥2b), and sICH, the multivariate analysis demonstrated that initial NIHSS, lack of revascular-ization success (TICI ≥2b), use of rescue therapy, and sICH were independent predictors of mortality (Table 5).

DiscussionMechanical thrombectomy using newer generation stent-retriever technology has shown increasing promise as an effective treatment for AIS; however, the influence of age in patients treated with these devices has not been studied. In the present study, we examine the influence of age on patients treated with the stent retriever, Solitaire-FR, in the NASA Registry.

Compared with the younger cohort, patients >80 years demonstrated a lower rate of good clinical outcome (27.3%

Table 1. Baseline Characteristics of the NASA ≤80 and >80 y Cohorts

Age ≤80 y (n=276)

n (%)

Age >80 y (n=78)n (%) P Value

Demographics

Age, y, mean (SD) Median (IQR, R)

62.2 (13.2)65 (53–73,

20–80)

85.2 (3.8)84 (82–88, 81–100)

<0.0001

Sex (female) 127 (46.2) 51 (65.4) 0.003

Race (white) 193 (71.5) 65 (83.3) 0.09

Vascular risk factors

Hypertension 202 (73.5) 69 (89.6) 0.003

Atrial fibrillation 96 (34.9) 52 (66.7) <0.0001

Diabetes mellitus 67 (24.3) 20 (25.6) 0.8

Hyperlipidemia 133 (48.2) 49 (62.8) 0.02

Smoking history 96 (35.3) 12 (15.4) 0.001

Coronary artery disease 76 (27.6) 35 (44.9) 0.004

Clinical presentation

Initial NIHSS, mean (SD) 17.9 (6.8) 18.9 (5.8) 0.2

Baseline mRS≤2 203 (94.4) 58 (90.6) 0.3

Occlusion site

MCA/M1 142 (51.6) 54 (69.2) 0.03

ICA terminus 69 (25.1) 13 (16.7)

Vertebrobasilar 34 (12.4) 2 (2.6)

Initial systolic BP, mean (SD) 144.4 (26.9) 149.2 (31.5) 0.2

Initial diastolic BP, mean (SD) 78.6 (17.0) 78.6 (20.2) 1

IV-tPA 117 (42.6) 37 (47.4) 0.4

Hospital transfer 123 (55.7) 36 (60.0) 0.5

BP indicates blood pressure; ICA, internal carotid artery; IV-tPA, intravenous tissue-type plasminogen activator; MCA, middle cerebral artery; mRS, modified Rankin Score; NASA, North American Solitaire-FR Stent-Retriever Acute Stroke; and NIHSS, National Institutes of Health Stroke Scale.

Table 2. Angiographic and Clinical Outcomes in the NASA ≤80 and >80 y Cohorts

Age ≤80 y (n=276)

n (%)

Age >80 y (n=78)n (%) P Value

Procedural factors

Time from onset to groin puncture, min, mean (SD)

364.7 (228.5) 358.9 (272.9) 0.9

Fluoroscopic time, min, mean (SD)

31.4 (23.2) 38.2 (32.5) 0.11

Time to revascularization or end of procedure, min, mean (SD)

71.7 (89.5) 93.1 (114.5) 0.08

General anesthesia 162 (73.0) 36 (60.0) 0.05

IA-tPA 70 (25.4) 30 (38.5) 0.02

Use of balloon guide catheter 116 (44.3) 33 (43.4) 0.9

Number of passes, mean (SD) 1.9 (1.1) 1.8 (1) 0.9

Use of rescue therapy 73 (26.5) 18 (23.1) 0.5

Angiographic outcome

TIMI≥2 231 (84.0) 65 (83.3) 0.9

TICI≥2a 241 (87.3) 69 (88.5) 0.8

TICI≥2b 201 (73.1) 54 (69.2) 0.5

Distal embolization 42 (15.8) 14 (18.7) 0.6

Embolization into new territory 16 (6.0) 3 (4.0) 0.8

Clinical outcome

mRS≤2 at 90 days 113 (45.4) 18 (27.3) 0.02

NIHSS at 90 days, mean (SD) (IQR, R)

20.9 (18.7)14 (3–42)

28.4 (18.0)42 (6–42)

0.02

Mortality at 90 days 68 (27.3) 29 (43.9) 0.01

sICH 25 (9.1) 10 (12.8) 0.4

IA-tPA indicates intra-arterial tissue-type plasminogen activator; IQR, interquartile range; mRS, modified Rankin Score; NIHSS, National Institutes of Health Stroke Scale; NASA, North American Solitaire-FR Stent-Retriever Acute Stroke; sICH, symptomatic intracranial hemorrhage; TICI, Treatment in Cerebral Ischemia; and TIMI, Thrombolysis in Myocardial Ischemia.

by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from

3634 Stroke December 2014

versus 45.4%; P=0.02) and increased mortality (43.9% ver-sus 27.3%; P=0.01) at 90 days compared with those ≤80 years. Our results are similar to other series that reported lower rates of good clinical outcome and higher rates of mortality in elderly patients undergoing mechanical throm-bectomy for AIS. In the Kurre et al3 series, which examined 109 patients ≥80 years of age who underwent mechanical thrombectomy, only 17.4% achieved a 90-day mRS≥2 and 47.7% were deceased. A single-center series that reported on the use of Merci, a first-generation retriever, showed that elderly patients had a mortality rate of 48% (15/31) versus 15% (11/75) in younger patients (odds ratio, 5.5; confidence interval, 2.1–14.2).4 Lower rates of good clinical outcome and higher rates of mortality have also been reported with multimodal treatment approaches in the elderly.5,11–13 In a separate study, Mono et al5 demonstrated less favorable out-come (28% versus 46%; P=0.019) and increased mortality (40% versus 22%; P=0.008) in octogenarians undergoing IA therapy (IV/IA thrombolysis, IA thrombolysis and mechani-cal thrombectomy) compared with patients <80 years of age. Similarly, lower rates of 90-day favorable outcome (28% versus 64.4%; P=0.002) and high rates of mortality (40% versus 15.3%) were also reported with a combined IV/IA approach in elderly patients versus their younger counter-parts by Mazighi et al.12 Similar to other series, our study

found no difference in the rate of sICH between elderly and younger cohorts.3,5,11–15

Although patients >80 years of age demonstrated lower rates of good clinical outcome at 90 days, elderly patients achieved similar revascularization rates (TICI≥2b; 69.2% versus 73.1%; P=0.5), but at a slower duration (93.1±114.5 versus 71.7±89.5 minutes; P=0.08) than younger patients. Revascularization rates in several studies examining ET in the elderly ranged from 62% to 87.9%,3–5,11,12,16 which are comparable with the findings from the current study. All but one series found no correlation between age >80 years and the likelihood of revas-cularization.11 Interpretation of revascularization success in previous series is difficult because of variability in the grad-ing scales used. This study reports TICI, which is the recom-mended revascularization scale by Zaidat et al.17

The natural history of ischemic stroke in the elderly is known to correlate with increased mortality and lower rates of good clinical outcome.18,19 Part of this effect may be because of a higher rate of withdrawal of care and medical comorbidi-ties in this population.15 In our study, patients >80 years of age had higher rates of hypertension, atrial fibrillation, hyperlipid-emia, smoking, and coronary artery disease than their younger counterparts. When adjusting for these comorbidities, age >80 years remained a strong independent predictor of poor clinical outcome and mortality. Our results are in agreement with 2 reports, which demonstrated that age >80 years was an independent predictor of poor outcome.11,14 The elderly also carry a higher burden of decreased neuronal plasticity, which also may contribute to the worse prognosis seen in this population.20

Table 3. Multivariate Analysis: Independent Predictors of Clinical Outcome and Mortality in the ≤80 and >80 Group

Clinical Outcome Mortality

Variable NParm DF χ2 P>χ2 χ2 P>χ2

Age>80 1 1 7.97 0.005 5.63 0.018

Sex 1 1 0.17 0.68 0.011 0.92

Hypertension 1 1 2.06 0.15 0.43 0.51

Atrial fibrillation

1 1 0.053 0.82 0.57 0.45

Hyperlipidemia 1 1 0.056 0.81 0.63 0.43

Smoking 1 1 0.036 0.85 0.88 0.35

CAD 1 1 0.0011 0.97 2.47 0.12

General anesthesia

1 1 9.38 0.002 3.92 0.048

IA-tPA 1 1 0.027 0.87 0.38 0.54

CAD indicates coronary artery disease; DF, degrees of freedom; and IA-tPA, intra-arterial tissue-type plasminogen activator.

Table 4. Multivariate Analysis: Independent Predictors of Clinical Outcome in >80 Cohort

Variable NParm DF χ2 P>χ2

NIHSSi 1 1 4.10 0.04

Time to revascularization 1 1 5.65 0.02

Number of passes 1 1 1.48 0.22

Rescue therapy 1 1 2.35 0.13

TICI success (≥2B) 1 1 0.233 0.63

IV-tPA 1 1 8.73 0.003

DF indicates degrees of freedom; IV-tPA, intravenous tissue-type plasminogen activator; NIHSSi, National Institutes of Health Stroke Scale initial; and TICI, Treatment in Cerebral Ischemia.

Figure. Distribution of 90-day modified Rankin Score (mRS) in the ≤80 and >80 years cohorts. The large grey lines indicate mRS of ≤2 (good clinical outcome) and 6 (mortality) with associated P values among the 2 groups.

by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from

Castonguay et al Influence of Age in the NASA Registry 3635

Proper patient selection is critical to determine which patients may benefit from ET. Large randomized controlled tri-als, including the Interventional Management of Stroke (IMS) III, TREVO 2, and SWIFT, excluded patients ≥85 years.1,2,21 The exclusion of the elderly population from RCTs has resulted in limited data on the benefit of ET in older patients. Previous studies, such as the randomized Third International Stroke Trial (IST-3) that included 1617 elderly patients, dem-onstrated the likely clinical benefit of intravenous thrombolysis in those >80 years of age and the association between throm-bolysis and improved outcome.22,23 Our study also examined factors within the elderly patient population, which may aid in identifying predictors of clinical outcome. Our study showed that within the >80 years cohort, factors that may influence better outcomes include shorter procedural times, fewer device passes, and limited use of rescue therapy. In our multivariate analysis, initial NIHSS, time to revascularization, and IV-tPA use were found to be independent predictors of clinical out-come in the >80 population. In addition, initial NIHSS, revas-cularization success, use of rescue therapy, and sICH were all independent predictors of mortality in patients >80 years of age. Interestingly, all patients within the >80 years cohort who had a sICH (10/28) died, suggesting that sICH is particularly detrimental in this older group. Because a higher initial NIHSS was observed in the >80 years group, more severe strokes in this cohort may have contributed to worse outcomes compared with the ≤80 years group. Although use of general anesthe-sia was reported to negatively impact clinical outcome in AIS patients,10 we did not see this effect within the elderly cohort; however, this may be related to the sample size.

LimitationsOur study has several limitations. This NASA substudy is lim-ited by its retrospective nature and site-adjudicated clinical and revascularization outcomes. Information on collateral sta-tus, infarct volume, and palliative care/withdrawal rates were not available in the original NASA cohort; these factors may have contributed to the poor outcomes and mortality seen in the elderly population. Collateral circulation is thought to sus-tain ischemic territory viability during a stroke, and the pres-ence of good collaterals has been associated with higher rates of improved clinical outcome.24,25 Elderly patients are believed to have poorer collaterals than their younger counterparts, and one study has reported that the odds of having decreased

collateral circulation increases with age.15,26 Final infarct vol-ume in ET has been shown as a strong independent predictor of good clinical outcome.15,27,28 Data suggest that smaller base-line infarct volumes in elderly AIS patients may be needed to increase the chances of a good clinical outcome.29

Although this substudy compared patients >80 years of age with those ≤80 years who underwent ET with the Solitaire-FR device, this study lacks a comparator arm of patients who received standard medical therapy alone.

ConclusionsTo date, this is the largest study comparing the use of a newer generation retriever in a young and elderly cohort. Patients >80 years of age demonstrated a lower rate of good clinical outcome and increased mortality with ET compared with patients ≤80 years of age. However, use of IV-tPA, lower NIHSS, and shorter time to revascularization are associated with better outcomes in the elderly group. Further studies are needed to compare ET with standard medical therapy alone in this patient population.

DisclosuresDr Zaidat is a Consultant, Covidien, Stryker, and Penumbra. Dr Gupta is a Consultant, Stryker Neurovascular, Rapid Medical, Covidien. Dr Malisch is a member of Data and Safety Monitoring Board. Dr Taqi is a Consultant Stryker Neurovascular. Dr Nogueira is a Consultant/advisory board Stryker Neurovascular (Trevo 2 Trial PI, DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention [DAWN] Trial PI), Covidien (SWIFT and SWIFT-PRIME Steering Committee, Solitaire FR Thrombectomy for Acute Revascularization [STAR] study Trial Core Laboratory), Penumbra (3-D Separator Trial Executive Committee). Dr Linfante is a Consultant, Shareholder Stryker/Surpass; Consultant and Proctor for Covidien and Consultant for Codman Neurovascular. Dr Dabus is a Shareholder Stryker/Surpass; Consultant and Proctor for Covidien and Consultant for Microvention. Dr Yoo received research grant, Penumbra, National Institutes of Health/National Institute of Neurological Disorders and Stroke, Dutch Heart Foundation. Dr Janardhan is a Board member, Insera Therapeutics, Inc; Advisory board, Penumbra; Research grant, Stryker Neurovascular, Cordis. Dr Mueller-Kronast is a member of Advisory Board, Covidien.

References 1. Nogueira RG, Lutsep HL, Gupta R, Jovin TG, Albers GW, Walker GA, et

al; TREVO 2 Trialists. Trevo versus Merci retrievers for thrombectomy revascularisation of large vessel occlusions in acute ischaemic stroke (TREVO 2): a randomised trial. Lancet. 2012;380:1231–1240.

2. Saver JL, Jahan R, Levy EI, Jovin TG, Baxter B, Nogueira RG, et al; SWIFT Trialists. Solitaire flow restoration device versus the Merci Retriever in patients with acute ischaemic stroke (SWIFT): a randomised, parallel-group, non-inferiority trial. Lancet. 2012;380:1241–1249.

3. Kurre W, Aguilar-Pérez M, Niehaus L, Fischer S, Schmid E, Bäzner H, et al. Predictors of outcome after mechanical thrombectomy for anterior circulation large vessel occlusion in patients aged ≥80 years. Cerebrovasc Dis. 2013;36:430–436.

4. Loh Y, Kim D, Shi ZS, Tateshima S, Vespa PM, Gonzalez NR, et al. Higher rates of mortality but not morbidity follow intracranial mechanical thrombectomy in the elderly. AJNR Am J Neuroradiol. 2010;31:1181–1185.

5. Mono ML, Lorenz R, Jung S, Arnold M, Galimanis A, Fischer U, et al. Intra-arterial thrombolysis for acute ischemic stroke in octogenarians. Cerebrovasc Dis. 2012;33:116–122.

6. Day J. Population of the United States by Age, Sex, Race, and Hispanic Origin: 1995–2050. US Bureau of the Census; Current

Table 5. Multivariate Analysis: Independent Predictors of Mortality in >80 Cohort

Variable NParm DF χ2 P>χ2

NIHSSi 1 1 4.97 0.026

Hypertension 1 1 3.43 0.064

CAD 1 1 2.24 0.13

TICI success (≥2B) 1 1 5.59 0.018

Rescue therapy 1 1 4.77 0.029

sICH 1 1 10.7 0.0011

CAD indicates coronary artery disease; DF, degrees of freedom; NIHSSi, National Institutes of Health Stroke Scale initial; sICH indicates symptomatic intracranial hemorrhage; and TICI, Treatment in Cerebral Ischemia.

by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from

3636 Stroke December 2014

Population Reports. Washington, DC: US Government Printing Office; 1996:25–1130.

7. Brown RD, Whisnant JP, Sicks JD, O’Fallon WM, Wiebers DO. Stroke incidence, prevalence, and survival: secular trends in Rochester, Minnesota, through 1989. Stroke. 1996;27:373–380.

8. Zaidat OO, Castonguay AC, Gupta R, Sun CH, Martin C, Holloway WE, et al. North American solitaire stent retriever acute stroke regis-try: post-marketing revascularization and clinical outcome results. J Neurointerv Surg. 2014;6:584–588.

9. Nguyen TN, Malisch T, Castonguay AC, Gupta R, Sun CH, Martin CO, et al. Balloon guide catheter improves revascularization and clinical out-comes with the Solitaire device: analysis of the North American Solitaire Acute Stroke Registry. Stroke. 2014;45:141–145.

10. Abou-Chebl A, Zaidat OO, Castonguay AC, Gupta R, Sun CH, Martin CO, et al. North American SOLITAIRE Stent-Retriever Acute Stroke Registry: choice of anesthesia and outcomes. Stroke. 2014;45:1396–1401.

11. Qureshi AI, Suri MF, Georgiadis AL, Vazquez G, Janjua NA. Intra-arterial recanalization techniques for patients 80 years or older with acute ischemic stroke: pooled analysis from 4 prospective studies. AJNR Am J Neuroradiol. 2009;30:1184–1189.

12. Mazighi M, Labreuche J, Meseguer E, Serfaty JM, Laissy JP, Lavallée PC, et al. Impact of a combined intravenous/intra-arterial approach in octogenarians. Cerebrovasc Dis. 2011;31:559–565.

13. Arkadir D, Eichel R, Gomori JM, Ben Hur T, Cohen JE, Leker RR. Multimodal reperfusion therapy for large hemispheric infarcts in octo-genarians: is good outcome a realistic goal? AJNR Am J Neuroradiol. 2012;33:1167–1169.

14. Kim D, Ford GA, Kidwell CS, Starkman S, Vinuela F, Duckwiler GR, et al; UCLA Intra-Arterial Thrombolysis Investigators. Intra-arterial thrombolysis for acute stroke in patients 80 and older: a comparison of results in patients younger than 80 years. AJNR Am J Neuroradiol. 2007;28:159–163.

15. Chandra RV, Leslie-Mazwi TM, Oh DC, Chaudhry ZA, Mehta BP, Rost NS, et al. Elderly patients are at higher risk for poor outcomes after intra-arterial therapy. Stroke. 2012;43:2356–2361.

16. Zeevi N, Kuchel GA, Lee NS, Staff I, McCullough LD. Interventional stroke therapies in the elderly: are we helping? AJNR Am J Neuroradiol. 2012;33:638–642.

17. Zaidat OO, Yoo AJ, Khatri P, Tomsick TA, von Kummer R, Saver JL, et al; Cerebral Angiographic Revascularization Grading (CARG) Collaborators; STIR Revascularization working group; STIR Thrombolysis in Cerebral Infarction (TICI) Task Force. Recommendations on angiographic revascularization grading standards for acute ischemic stroke: a consensus statement. Stroke. 2013;44:2650–2663.

18. Kammersgaard LP, Jørgensen HS, Reith J, Nakayama H, Pedersen PM, Olsen TS; Copenhagen Stroke Study. Short- and long-term prognosis for very old stroke patients. The Copenhagen Stroke Study. Age Ageing. 2004;33:149–154.

19. Di Carlo A, Lamassa M, Pracucci G, Basile AM, Trefoloni G, Vanni P, et al. Stroke in the very old: clinical presentation and determinants of 3-month functional outcome: a European perspective. European BIOMED Study of Stroke Care Group. Stroke. 1999;30:2313–2319.

20. Sharma JC, Fletcher S, Vassallo M. Strokes in the elderly - higher acute and 3-month mortality—an explanation. Cerebrovasc Dis. 1999;9:2–9.

21. Broderick JP, Palesch YY, Demchuk AM, Yeatts SD, Khatri P, Hill MD, et al; Interventional Management of Stroke (IMS) III Investigators. Endovascular therapy after intravenous t-PA versus t-PA alone for stroke. N Engl J Med. 2013;368:893–903.

22. Sandercock P, Wardlaw JM, Lindley RI, Dennis M, Cohen G, Murray G, et al. The benefits and harms of intravenous thrombolysis with recom-binant tissue plasminogen activator within 6h of acute ischaemic stroke (the third international stroke trial [IST-3]: a randomized controlled trial. Lancet. 2012;379:2353–2363.

23. Mishra NK, Ahmed N, Andersen G, Egido JA, Lindsberg PJ, Ringleb PA, et al; VISTA Collaborators; SITS Collaborators. Thrombolysis in very elderly people: controlled comparison of SITS International Stroke Thrombolysis Registry and Virtual International Stroke Trials Archive. BMJ. 2010;341:c6046.

24. Nambiar V, Sohn SI, Almekhlafi MA, Chang HW, Mishra S, Qazi E, et al. CTA collateral status and response to recanalization in patients with acute ischemic stroke. AJNR Am J Neuroradiol. 2014;35:884–890.

25. Bang OY, Saver JL, Kim SJ, Kim GM, Chung CS, Ovbiagele B, et al. Collateral flow predicts response to endovascular therapy for acute isch-emic stroke. Stroke. 2011;42:693–699.

26. Arsava EM, Vural A, Akpinar E, Gocmen R, Akcalar S, Oguz KK, et al. The detrimental effect of aging on leptomeningeal collaterals in ischemic stroke. J Stroke Cerebrovasc Dis. 2014;23:421–426.

27. Zaidi SF, Aghaebrahim A, Urra X, Jumaa MA, Jankowitz B, Hammer M, et al. Final infarct volume is a stronger predictor of outcome than recanalization in patients with proximal middle cerebral artery occlusion treated with endovascular therapy. Stroke. 2012;43:3238–3244.

28. Yoo AJ, Chaudhry ZA, Nogueira RG, Lev MH, Schaefer PW, Schwamm LH, et al. Infarct volume is a pivotal biomarker after intra-arterial stroke therapy. Stroke. 2012;43:1323–1330.

29. Ribo M, Flores A, Mansilla E, Rubiera M, Tomasello A, Coscojuela P, et al. Age-adjusted infarct volume threshold for good outcome after endo-vascular treatment. J Neurointerv Surg. 2014;6:418–422.

by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from

NogueiraPeng R. Chen, Gavin W. Britz, Ritesh Kaushal, Ashish Nanda, Mohammad A. Issa and Raul G.Michael G. Abraham, Vallabh Janardhan, Hashem Shaltoni, Albert J. Yoo, Alex Abou-Chebl,

Hormozd Bozorgchami, Andrew Xavier, Ansaar T. Rai, Michael T. Froehler, Aamir Badruddin,Joey E. English, Italo Linfante, Guilherme Dabus, Tim W. Malisch, Franklin A. Marden,

Mueller-Kronast,Rishi Gupta, Chung-Huan J. Sun, Coleman Martin, William E. Holloway, Nils Alicia C. Castonguay, Osama O. Zaidat, Roberta Novakovic, Thanh N. Nguyen, M. Asif Taqi,

Solitaire Stent-Retriever Acute Stroke RegistryInfluence of Age on Clinical and Revascularization Outcomes in the North American

Print ISSN: 0039-2499. Online ISSN: 1524-4628 Copyright © 2014 American Heart Association, Inc. All rights reserved.

is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231Stroke doi: 10.1161/STROKEAHA.114.006487

2014;45:3631-3636; originally published online October 30, 2014;Stroke. 

http://stroke.ahajournals.org/content/45/12/3631World Wide Web at:

The online version of this article, along with updated information and services, is located on the

http://stroke.ahajournals.org/content/suppl/2016/04/06/STROKEAHA.114.006487.DC2.html http://stroke.ahajournals.org/content/suppl/2014/10/30/STROKEAHA.114.006487.DC1.html

Data Supplement (unedited) at:

  http://stroke.ahajournals.org//subscriptions/

is online at: Stroke Information about subscribing to Subscriptions: 

http://www.lww.com/reprints Information about reprints can be found online at: Reprints:

  document. Permissions and Rights Question and Answer process is available in the

Request Permissions in the middle column of the Web page under Services. Further information about thisOnce the online version of the published article for which permission is being requested is located, click

can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office.Strokein Requests for permissions to reproduce figures, tables, or portions of articles originally publishedPermissions:

by guest on April 14, 2016http://stroke.ahajournals.org/Downloaded from

SUPPLEMENTAL MATERIAL

Supplementary Table I. Characteristics of >80 years cohort dichotomized by 90-day clinical outcome. mRS ≤2

(N=19) N (%) mRS >2

(N=47) N (%) P-value

Demographics Age (years)(mean (SD)) Median (IQR, R)

85.0 (4.8) 84 (81-86)

85.6 (3.7) 85 (83-89)

0.6

Gender (female) 12 (63.2) 33 (70.2) 0.6 Race (white) 16 (84.2) 38 (80.9) 0.9 Vascular Risk Factors Hypertension 15 (79.0) 44 (93.62) 0.08 Atrial Fibrillation 15 (79.0) 31 (66.0) 0.3 Diabetes Mellitus 5 (26.3) 10 (21.3) 0.7 Hyperlipidemia 12 (63.2) 31 (66.0) 0.8 Smoking history 3 (15.8) 6 (12.8) 0.7 Coronary Artery Disease 8 (42.1) 23 (48.9) 0.8 Clinical Presentation Initial NIHSS (mean (SD)) 18.5 (5.0) 19.4 (6.2) 0.5 Occlusion Site MCA/M1 ICA terminus Vertebro-basilar

17 (89.5) 2 (10.5)

0 (0)

36 (76.6) 9 (19.2) 2 (4.3)

0.6

Initial Systolic BP (mean (SD)) 139.3 (29.1) 148.2 (30.8) 0.3 Initial Diastolic BP (mean (SD)) 77.1 (20.9) 77.4 (21.3) 1 IV tPA 12 (63.2) 21 (44.7) 0.2 Procedural Factors Time from onset to groin puncture (min) (mean (SD))

278.2 (196.8) 381.3 (294.7) 0.1

Fluoroscopic Time (min) (mean (SD))

24.1 (22.4) 41.3 (35.6) 0.04

Time to revascularization or end of procedure (min) (mean (SD))

43.1 (15.6) 101.5 (114.0) 0.01

General Anesthesia 5 (41.7) 23 (62.2) 0.3 IA t-PA 5 (26.3) 19 (40.4) 0.4 Use of Balloon Guide Catheter 11 (61.1) 16 (34.8) 0.06 Number of Passes (mean SD) median (IQR, R)

1.4 (0.8) 1 (1-2)

1.9 (1) 2 (1-3)

0.02

Use of Rescue Therapy 1 (5.3) 16 (34.0) 0.02 Angiographic Outcome TIMI ≥ 2 18 (94.7) 37 (78.7) 0.1 TICI ≥ 2a 18 (94.7) 41 (87.2) 0.7 TICI ≥ 2b 17 (89.5) 29 (63.0) 0.04 Distal Embolization 1 (5.3) 11 (24.4) 0.09 Embolization into New Territory 1 (5.3) 2 (4.4) 1 Clinical Outcome NIHSS at 90 days (mean (SD)) 1.3 (1.8) 35.8 (12.4) <0.0001 Mortality at 90 days 0 (0) 28 (59.5) <0.0001 sICH 0 (0) 10 (21.3) 0.05

Supplementary Table II. Characteristics of >80 years cohort dichotomized by mortality.

Alive (N=37) N (%)

Deceased (N=28) N (%)

P-value

Demographics Age (years)(mean (SD)) Median (IQR, R)

84.9 (3.9) 84 (82-87)

86.3 (4.2) 85 (83-90)

0.2

Gender (female) 23 (62.2) 21 (75.0) 0.3 Race (white) 30 (81.1) 23 (82.1) 1 Vascular Risk Factors Hypertension 30 (81.1) 28 (100.0) 0.01 Atrial Fibrillation 28 (75.7) 17 (60.7) 0.2 Diabetes Mellitus 9 (24.3) 6 (21.4) 0.8 Hyperlipidemia 23 (62.2) 19 (67.9) 0.6 Smoking history 4 (10.8) 4 (14.3) 0.7 Coronary Artery Disease 12 (32.4) 18 (64.3) 0.01 Clinical Presentation Initial NIHSS (mean (SD)) 18.2 (4.8) 20.7 (6.7) 0.1 Occlusion Site MCA/M1 ICA terminus Vertebro-basilar

27 (73.0) 4 (10.8) 1 (2.7)

17 (60.7)

7 (25) 1 (3.6)

0.6

Initial Systolic BP (mean (SD)) 141.1 (27.4) 152.2 (34.0) 0.2 Initial Diastolic BP (mean (SD)) 77.1 (19.1) 77.4 (24.0) 1 IV tPA 16 (43.2) 16 (57.1) 0.3 Procedural Factors Time from onset to groin puncture (min) (mean (SD))

327.9 (219.9) 384.2 (337.2) 0.5

Fluoroscopic Time (min) (mean (SD))

29.0 (21.3) 39.0 (32.0) 0.2

Time to revascularization or end of procedure (min) (mean (SD))

74.6 (89.4) 95.5 (110.0) 0.5

General Anesthesia 13 (50.0) 14 (63.6) 0.3 IA t-PA 13 (35.1) 10 (35.7) 1 Use of Balloon Guide Catheter 15 (41.7) 11 (40.7) 0.9 Number of Passes (mean SD) median (IQR, R)

1.7 (1.0) 1 (1-2)

1.9 (0.9) 2 (1-3)

0.3

Use of Rescue Therapy 6 (16.2) 10 (35.7) 0.1 Angiographic Outcome TIMI ≥ 2 33 (89.2) 22 (78.6) 0.2 TICI ≥ 2a 34 (91.9) 24 (85.7) 0.4 TICI ≥ 2b 32 (86.5) 14 (50) 0.001 Distal Embolization 6 (16.7) 6 (21.4) 0.6 Embolization into New Territory 1 (2.7) 1 (3.7) 0.8 Clinical Outcome NIHSS at 90 days (median (IQR, R) 3 (0-14) 42 (42-42) <0.0001 sICH 0 (0) 10 (35.7) 0.001

Supplementary Figure I. Distribution of good clinical outcome (mRS≤2) by age strata (in years).

37

Abstract 13

북미 Solitaire 스텐트-제거기 급성뇌졸중 레지스트리에서 임상 및 재개통 결과에 대한 나이의 영향

Influence of Age on Clinical and Revascularization Outcomes in the North American Solitaire Stent-Retriever Acute Stroke Registry

Alicia C. Castonguay, PhD; Osama O. Zaidat, MD, MS; Roberta Novakovic, MD; Thanh N. Nguyen, MD; M. Asif Taqi, MD; Rishi Gupta, MD; Chung-Huan J. Sun, MD; Coleman Martin, MD; William E. Holloway, MD; Nils Mueller-Kronast, MD; Joey E. English, MD; Italo Linfante, MD; Guilherme Dabus, MD; Tim

W. Malisch, MD; Franklin A. Marden, MD; Hormozd Bozorgchami, MD; Andrew Xavier, MD; Ansaar T. Rai, MD; Michael T. Froehler, MD, PhD; Aamir Badruddin, MD; Michael G. Abraham, MD; Vallabh Janardhan, MD; Hashem Shaltoni, MD; Albert J. Yoo, MD; Alex Abou-Chebl, MD; Peng R. Chen, MD;

Gavin W. Britz, MD; Ritesh Kaushal, MD; Ashish Nanda, MD; Mohammad A. Issa, MD; Raul G. Nogueira, MD

(Stroke. 2014;45:3631-3636.)

Key Words: age groups ■aged ■stroke ■thrombectomy

배경과 목적

Solitaire With the Intention for Thrombectomy (SWIFT)와

Thrombectomy REvascularization of large Vessel Occlusions

in acute ischemic stroke (TREVO 2)의 임상시험 결과는 기계

적 혈전 제거술의 개선된 재개통률을 보였다; 그러나, 고령 인구

에서의 결과는 아직 잘 이해되지 못한 상태이다. 여기서 우리는

North American Solitaire-FR Stent-Retriever Acute Stroke

(NASA) 레지스트리 내에서 임상 및 혈관조영 결과에 대한 나이

의 영향을 보고하고자 한다.

방법

NASA 레지스트리는 Solitaire-FR로 치료받은 일련의 환자들

자료를 제출할 기관들을 모집하였다. 임상 및 혈관조영 결과에

대한 나이의 영향은 코호트를 80세 이하와 80세 초과로 이분하

여 평가되었다.

결과

24개 센터에서 354명의 환자들이 치료를 받았다; 276명의 환자

는 80세 이하였고 78명은 80세를 넘었다. 80세 이하와 80세 초

과 코호트에서의 평균 연령은 각각 62.2±13.2세 및 85.2±3.8세

였다. 80세 초과 환자 중 27.3%는 90일째 수정랜킨척도 2점 이

하로 80세 이하에서는 45.4%이었다(P=0.02). 사망률은 80세 초

과 및 80세 이하 코호트에서 각각 43.9%와 27.3%이었다

(P=0.01). 혈관재개통까지의 시간, 재개통 성공률, 또는 증상성

두개내출혈은 군간에 유의한 차이가 없었다. 다변량 분석은 80세

초과 여부가 불량한 임상 결과 및 사망률의 독립적인 예측 인자

를 보여주었다. 80세 초과 코호트 내에서, NIHSS, 재개통 비율,

구조 치료(rescue therapy) 여부, 및 증상성 두개내 출혈은 사망

의 독립적인 예측인자였다.

결론

80세 이상의 연령은 NASA 레지스트리에서 젊은 환자들에 비해

불량한 임상 결과 및 사망률 증가를 예측한다. 그러나, 정맥 조직

형 플라스미노겐 활성제의 사용, 낮은 NIHSS, 짧은 재관류 시간

은 좋은 결과와 연관된다. 이 코호트에서 약물치료와 비교하여 혈

관내 치료의 역할을 이해하기 위하여 추가적인 연구가 필요하다.

3634 Stroke December 2014

versus 45.4%; P=0.02) and increased mortality (43.9% ver-sus 27.3%; P=0.01) at 90 days compared with those ≤80 years. Our results are similar to other series that reported lower rates of good clinical outcome and higher rates of mortality in elderly patients undergoing mechanical throm-bectomy for AIS. In the Kurre et al3 series, which examined 109 patients ≥80 years of age who underwent mechanical thrombectomy, only 17.4% achieved a 90-day mRS≥2 and 47.7% were deceased. A single-center series that reported on the use of Merci, a first-generation retriever, showed that elderly patients had a mortality rate of 48% (15/31) versus 15% (11/75) in younger patients (odds ratio, 5.5; confidence interval, 2.1–14.2).4 Lower rates of good clinical outcome and higher rates of mortality have also been reported with multimodal treatment approaches in the elderly.5,11–13 In a separate study, Mono et al5 demonstrated less favorable out-come (28% versus 46%; P=0.019) and increased mortality (40% versus 22%; P=0.008) in octogenarians undergoing IA therapy (IV/IA thrombolysis, IA thrombolysis and mechani-cal thrombectomy) compared with patients <80 years of age. Similarly, lower rates of 90-day favorable outcome (28% versus 64.4%; P=0.002) and high rates of mortality (40% versus 15.3%) were also reported with a combined IV/IA approach in elderly patients versus their younger counter-parts by Mazighi et al.12 Similar to other series, our study

found no difference in the rate of sICH between elderly and younger cohorts.3,5,11–15

Although patients >80 years of age demonstrated lower rates of good clinical outcome at 90 days, elderly patients achieved similar revascularization rates (TICI≥2b; 69.2% versus 73.1%; P=0.5), but at a slower duration (93.1±114.5 versus 71.7±89.5 minutes; P=0.08) than younger patients. Revascularization rates in several studies examining ET in the elderly ranged from 62% to 87.9%,3–5,11,12,16 which are comparable with the findings from the current study. All but one series found no correlation between age >80 years and the likelihood of revas-cularization.11 Interpretation of revascularization success in previous series is difficult because of variability in the grad-ing scales used. This study reports TICI, which is the recom-mended revascularization scale by Zaidat et al.17

The natural history of ischemic stroke in the elderly is known to correlate with increased mortality and lower rates of good clinical outcome.18,19 Part of this effect may be because of a higher rate of withdrawal of care and medical comorbidi-ties in this population.15 In our study, patients >80 years of age had higher rates of hypertension, atrial fibrillation, hyperlipid-emia, smoking, and coronary artery disease than their younger counterparts. When adjusting for these comorbidities, age >80 years remained a strong independent predictor of poor clinical outcome and mortality. Our results are in agreement with 2 reports, which demonstrated that age >80 years was an independent predictor of poor outcome.11,14 The elderly also carry a higher burden of decreased neuronal plasticity, which also may contribute to the worse prognosis seen in this population.20

Table 3. Multivariate Analysis: Independent Predictors of Clinical Outcome and Mortality in the ≤80 and >80 Group

Clinical Outcome Mortality

Variable NParm DF χ2 P>χ2 χ2 P>χ2

Age>80 1 1 7.97 0.005 5.63 0.018

Sex 1 1 0.17 0.68 0.011 0.92

Hypertension 1 1 2.06 0.15 0.43 0.51

Atrial fibrillation

1 1 0.053 0.82 0.57 0.45

Hyperlipidemia 1 1 0.056 0.81 0.63 0.43

Smoking 1 1 0.036 0.85 0.88 0.35

CAD 1 1 0.0011 0.97 2.47 0.12

General anesthesia

1 1 9.38 0.002 3.92 0.048

IA-tPA 1 1 0.027 0.87 0.38 0.54

CAD indicates coronary artery disease; DF, degrees of freedom; and IA-tPA, intra-arterial tissue-type plasminogen activator.

Table 4. Multivariate Analysis: Independent Predictors of Clinical Outcome in >80 Cohort

Variable NParm DF χ2 P>χ2

NIHSSi 1 1 4.10 0.04

Time to revascularization 1 1 5.65 0.02

Number of passes 1 1 1.48 0.22

Rescue therapy 1 1 2.35 0.13

TICI success (≥2B) 1 1 0.233 0.63

IV-tPA 1 1 8.73 0.003

DF indicates degrees of freedom; IV-tPA, intravenous tissue-type plasminogen activator; NIHSSi, National Institutes of Health Stroke Scale initial; and TICI, Treatment in Cerebral Ischemia.

Figure. Distribution of 90-day modified Rankin Score (mRS) in the ≤80 and >80 years cohorts. The large grey lines indicate mRS of ≤2 (good clinical outcome) and 6 (mortality) with associated P values among the 2 groups.

3634 Stroke December 2014

versus 45.4%; P=0.02) and increased mortality (43.9% ver-sus 27.3%; P=0.01) at 90 days compared with those ≤80 years. Our results are similar to other series that reported lower rates of good clinical outcome and higher rates of mortality in elderly patients undergoing mechanical throm-bectomy for AIS. In the Kurre et al3 series, which examined 109 patients ≥80 years of age who underwent mechanical thrombectomy, only 17.4% achieved a 90-day mRS≥2 and 47.7% were deceased. A single-center series that reported on the use of Merci, a first-generation retriever, showed that elderly patients had a mortality rate of 48% (15/31) versus 15% (11/75) in younger patients (odds ratio, 5.5; confidence interval, 2.1–14.2).4 Lower rates of good clinical outcome and higher rates of mortality have also been reported with multimodal treatment approaches in the elderly.5,11–13 In a separate study, Mono et al5 demonstrated less favorable out-come (28% versus 46%; P=0.019) and increased mortality (40% versus 22%; P=0.008) in octogenarians undergoing IA therapy (IV/IA thrombolysis, IA thrombolysis and mechani-cal thrombectomy) compared with patients <80 years of age. Similarly, lower rates of 90-day favorable outcome (28% versus 64.4%; P=0.002) and high rates of mortality (40% versus 15.3%) were also reported with a combined IV/IA approach in elderly patients versus their younger counter-parts by Mazighi et al.12 Similar to other series, our study

found no difference in the rate of sICH between elderly and younger cohorts.3,5,11–15

Although patients >80 years of age demonstrated lower rates of good clinical outcome at 90 days, elderly patients achieved similar revascularization rates (TICI≥2b; 69.2% versus 73.1%; P=0.5), but at a slower duration (93.1±114.5 versus 71.7±89.5 minutes; P=0.08) than younger patients. Revascularization rates in several studies examining ET in the elderly ranged from 62% to 87.9%,3–5,11,12,16 which are comparable with the findings from the current study. All but one series found no correlation between age >80 years and the likelihood of revas-cularization.11 Interpretation of revascularization success in previous series is difficult because of variability in the grad-ing scales used. This study reports TICI, which is the recom-mended revascularization scale by Zaidat et al.17

The natural history of ischemic stroke in the elderly is known to correlate with increased mortality and lower rates of good clinical outcome.18,19 Part of this effect may be because of a higher rate of withdrawal of care and medical comorbidi-ties in this population.15 In our study, patients >80 years of age had higher rates of hypertension, atrial fibrillation, hyperlipid-emia, smoking, and coronary artery disease than their younger counterparts. When adjusting for these comorbidities, age >80 years remained a strong independent predictor of poor clinical outcome and mortality. Our results are in agreement with 2 reports, which demonstrated that age >80 years was an independent predictor of poor outcome.11,14 The elderly also carry a higher burden of decreased neuronal plasticity, which also may contribute to the worse prognosis seen in this population.20

Table 3. Multivariate Analysis: Independent Predictors of Clinical Outcome and Mortality in the ≤80 and >80 Group

Clinical Outcome Mortality

Variable NParm DF χ2 P>χ2 χ2 P>χ2

Age>80 1 1 7.97 0.005 5.63 0.018

Sex 1 1 0.17 0.68 0.011 0.92

Hypertension 1 1 2.06 0.15 0.43 0.51

Atrial fibrillation

1 1 0.053 0.82 0.57 0.45

Hyperlipidemia 1 1 0.056 0.81 0.63 0.43

Smoking 1 1 0.036 0.85 0.88 0.35

CAD 1 1 0.0011 0.97 2.47 0.12

General anesthesia

1 1 9.38 0.002 3.92 0.048

IA-tPA 1 1 0.027 0.87 0.38 0.54

CAD indicates coronary artery disease; DF, degrees of freedom; and IA-tPA, intra-arterial tissue-type plasminogen activator.

Table 4. Multivariate Analysis: Independent Predictors of Clinical Outcome in >80 Cohort

Variable NParm DF χ2 P>χ2

NIHSSi 1 1 4.10 0.04

Time to revascularization 1 1 5.65 0.02

Number of passes 1 1 1.48 0.22

Rescue therapy 1 1 2.35 0.13

TICI success (≥2B) 1 1 0.233 0.63

IV-tPA 1 1 8.73 0.003

DF indicates degrees of freedom; IV-tPA, intravenous tissue-type plasminogen activator; NIHSSi, National Institutes of Health Stroke Scale initial; and TICI, Treatment in Cerebral Ischemia.

Figure. Distribution of 90-day modified Rankin Score (mRS) in the ≤80 and >80 years cohorts. The large grey lines indicate mRS of ≤2 (good clinical outcome) and 6 (mortality) with associated P values among the 2 groups.