Neuroradiology

, Volume 54, Issue 2, pp 147–154 | Cite as

Initial experience with a self-expanding retrievable stent for recanalization of large vessel occlusions in acute ischemic stroke

  • Bijoy K. Menon
  • Puneet Kochar
  • Andrew Ah-Seng
  • Mohammed A. Almekhlafi
  • Jayesh Modi
  • John H. Wong
  • Mark E. Hudon
  • Will Morrish
  • Andrew M. Demchuk
  • Mayank Goyal
Interventional Neuroradiology

Abstract

Introduction

Quicker recanalization results in better clinical outcomes in patients with acute ischemic strokes. We describe our experience with the use of a self-expanding, fully retrievable stent in acute intracranial occlusions.

Methods

Patients who underwent intra-arterial procedures with a self-expanding, fully retrievable stent for acute ischemic strokes at our center in 2009 were included in this study. The primary outcome was recanalization [Thrombolysis in Myocardial Infarction (TIMI) grade 2/3] at end of procedure. Secondary endpoints were procedural interval times, incidence of vasospasm, rupture of vessels, device-related complications, groin complications, postprocedural intracerebral hemorrhage (ICH) on noncontrast CT, and all-cause mortality.

Results

Fourteen patients (mean age 62.1 years, range 34–81 years; six males) were included in the study. Sites of occlusion are as follows: M1 middle cerebral artery (MCA, n = 8), M2 MCA (n = 1), proximal basilar artery (n = 1), and distal basilar artery (n = 4). An additional device or technique was used in 9 of 14 patients prior to the use of the retrievable stent. Twelve out of 14 (85.7%) achieved TIMI 2–3 recanalization with 4 of 14 (28.6%) achieving TIMI 3. Eight of 14 (57.1%) patients had modified Rankin Scale (0–2) at 3 months or discharge. ICH on follow-up CT was noted in 28.6% (4 of 14) of patients. All-cause mortality was 2 of 14 (14.3%).

Conclusion

Use of a novel self-expanding, fully retrievable stent resulted in fast and very high recanalization rates in acute ischemic strokes with intravascular occlusions.

Keywords

Retrievable stent Endovascular intervention Acute ischemic stroke 

Introduction

Therapy in acute ischemic stroke is focused on achieving faster recanalization and reperfusion [1, 2]. The last few years have seen development of many new devices and techniques which aim to achieve these goals [3, 4]. Recent case series have reported excellent results with self-expandable retrievable stents in patients with occlusions not responding to other techniques [5, 6, 7, 8]. Use of these stents results in faster recanalization with the ability to retrieve a large part of the clot. Complications due to permanent deployment of the stent are avoided. We are presenting our initial experience of 14 cases with a temporary self-expandable, fully retrievable stent in acute intracranial occlusions.

Methods

The Calgary Stroke Program serves a population of about 1.5 million people and is centralized at Foothills Medical Centre. Roughly 150 thrombolysis cases per year are managed at Foothills hospital. Patients with significant clinical symptoms and proximal occlusions [including M2 middle cerebral arteries (MCAs)] are considered for endovascular thrombolysis. Fourteen patients with acute intracranial occlusion (from March 2009 to September 2010) identified on CT angiography (CTA) presenting to our center within 6 h from stroke onset in whom a retrievable stent was used as part of attempts at intra-arterial recanalization were included in the study. Two patients included in the ongoing Interventional Management of Stroke (IMS) III Trial [9] and two patients included in the Albumin in Acute Ischemic Stroke 2 Trial [10] were excluded from analysis. This study has institutional review board approval.

The primary clinical outcome was modified Rankin Scale (mRS) ≤2 at 3 months; where 3 months mRS was unavailable, we imputed it using the last score carried forward after hospital discharge. The primary imaging outcome was the rate of recanalization, defined as Thrombolysis in Myocardial Infarction (TIMI) grade 2 or 3 at completion of the angiogram as in IMS I Study [11]. Safety outcomes were procedural complications such as vessel rupture, dissections and groin complications, presence of intracranial hemorrhage (ICH) on follow-up computed tomography (CT) as defined in European Cooperative Acute Stroke Study II [12], distal emboli into the occluded vascular bed, and all-cause mortality. We also studied interval times in the acute treatment process, noted from the patients' health records and from time-stamped images in our picture archiving and communication system. Data are described using standard descriptive statistics.

Technique

Decision to proceed to intra-arterial therapy was taken by the treating physician in consultation with an experienced neurointerventionist. Seven out of 14 patients had received i.v. recombinant tissue plasminogen activator (0.9 mg/kg) as part of our acute stroke treatment protocol. Based on prior evidence, we avoid treating patients by endovascular techniques if the baseline noncontrast CT (NCCT) Alberta Stroke Program Early CT Score <4 [13, 14]. In 7 of 14 patients, a different mechanical device (Penumbra aspiration catheter) was used first based on the neurointerventionist's discretion. All procedures were performed in a dedicated biplane neuroangiography suite (Siemens Axiom Artis; Siemens, Erlangen, Germany). Assistance from the anesthesia on-call service was sought depending on the patients' status ensuring that overall time to start of the procedure was not unduly prolonged.

A standard technique for femoral arterial puncture was adopted. After confirming the site of occlusion, a 6-Fr guiding catheter (Flexor Shuttle Select; Cook Medical Inc.; Strada, St. Jude Medical) was advanced into the distal internal carotid artery (ICA). A 0.021-in PROWLER SELECT Plus microcatheter (Cordis Neurovascular Inc., Miami Lakes, FL) was advanced through a Neuron guide catheter (Penumbra, Inc., San Leandro, CA) over a 0.014-in steerable microwire [0.014-in Transcend wire (Boston Scientific/Target Therapeutics) or 0.012-in double curve Headliner wire (MicroVention/Terumo)]. The wire was gently advanced across the clot, and the microcatheter advanced over it. After removing the microwire, a superselective angiogram was taken to confirm patency of vessel distal to occlusion and to judge vessel size. A 4 × 20-mm self-expandable retrievable stent (Solitaire™ AB, Solitaire™ FR; Microtherapeutics Inc., ev3 Neurovascular, Irvine, CA) was advanced to the tip of the microcatheter and deployed into the clot by withdrawing the microcatheter and unsheathing the stent. Control angiogram was taken immediately after stent deployment and at regular intervals to assess recanalization of target vessel and perfusion of the distal bed. The stent was left in the deployed position for about 5 min. The microcatheter was then resheathed partially over the stent in some patients, leaving approximately 5–10 mm of stent outside the catheter. The assembly, either partially resheathed or in the unfolded state, was carefully removed with negative manual suction applied through the guide catheter. We did not use a balloon guide catheter to achieve flow arrest during stent retrieval. Depending on the success of the initial deployment in achieving recanalization and clot retrieval, the process was repeated or terminated. An additional device or technique was also used in some cases based on the discretion of the neurointerventionist. After recanalization of the primary target vessel, a complete angiogram was obtained to assess the degree of distal flow and to evaluate for the presence of distal emboli. If it was felt that there were sizeable distal emboli that were large enough to produce further ischemic insult to eloquent brain and were easily approachable through a microcatheter, an attempt was made to achieve recanalization using a smaller microcatheter (such as Excelsior SL-10) and use of IA tissue plasminogen activator (tPA). If the emboli were in small pial branches (e.g., distal M3 or M4 segment) or not accessible, no further attempt at recanalization was made. Baseline and final TIMI scores were recorded by the neurointerventionist at the end of all procedures.

Results

Fourteen patients were included in the study. Mean age was 62.1 years (range 34–81 years), and six (42.8%) were males (Table 1). Sites of occlusion are as follows: carotid T (n = 1), M1 MCA (n = 7), M2 MCA (n = 1), proximal basilar artery (n = 1), and distal basilar artery (n = 4).
Table 1

Baseline characteristics, site of occlusion, recanalization rates, and clinical outcomes in our series (n = 14)

Subject no.

Age (years)

Sex

Occlusions site

Intravenous tPA

Pre-stenting therapy

Post-stent therapy

ICH

Initial NIHSS

24 h NIHSS

Preprocedure TIMI

Postprocedure TIMI

mRS at 3 months or discharge

1

69

M

Proximal basilar artery

Yes

Penumbra, IA tPA, abciximab

None

No

5

2

0

2

0

2

53

F

Left M2 MCA

No

Penumbra, IA tPA, abciximab

None

No

N/A (intubated)

N/A (intubated)

0

3

0

3

41

F

Right M1 MCA

Yes

None

None

No

17

5

0

2

1

4

60

M

Right M1 MCA

No

Penumbra, IA tPA

None

No

9

4

0

2

2

5

34

F

Distal basilar artery

Yes

Penumbra

Penumbra, abciximab

No

N/A (intubated)

2

0

2

1

6

70

M

Left M1 MCA

No

None

None

No

14

2

0

3

0

7

40

M

Right M1 MCA

Yes

Penumbra, IA tPA

None

No

15

3

1

3

1

8

76

F

Left M1 MCA

No

Penumbra

None

HT-1

22

18

0

1

4

9

81

F

Left M1 MCA

No

Penumbra

IA tPA

SAH + PH-1

13

24

0

1

6

10

79

F

Right M1 MCA

Yes

None

None

No

18

18

0

2

3

11

62

F

Distal basilar artery

No

IA tPA

IA tPA

HT-1

16

16

0

2

4

12

72

M

Distal basilar artery

No

Gateway balloon

None

HT-1

12

5

0

3

1

13

76

F

Right carotid T

Yes

None

None

No

9

6

0

2

3

14

79

M

Distal basilar artery

Yes

None

IA tPA

No

N/A (intubated)

N/A (intubated)

0

2

6

An additional device or technique [Penumbra aspiration catheter, mechanical thrombolysis with microcatheter/microwire combination, IA tPA (4–17 mg), and IA abciximab (4–18 mg)] was used in 9 of 14 patients prior to the use of the retrievable stent with the stent used as rescue therapy in these patients. In the remaining, stent was used as the primary mechanical device. Successful stent deployment was achieved in all 14 patients (100%). Recanalization of the occluded vessel (TIMI 2/3) was noted in control angiograms taken immediately after first stent deployment in 11 of 14 patients. Additional passes with the stent were required in 12 of 14 patients when reocclusion was noted in control angiograms repeated after 5 min of stent deployment. The number of passes needed to achieve recanalization ranged from one to five. Twelve out of 14 (85.7%) achieved TIMI 2–3 recanalization with 4 of 14 (28.6%) achieving TIMI 3. Interval time from stent deployment to stent withdrawal was 3–13 min for single deployment. Median puncture to recanalization time (n = 12) was 84 min (range 26–164 min). Median first angiography to recanalization time (n = 12) was 72 min (range 12–136 min). Median time interval from first stent deployment to recanalization (n = 12) was 17.5 min (range 1–60 min). This time interval includes time for additional passes with the stent and any IA tPA infused through a microcatheter into distal pial arteries by the neurointerventionist after last stent deployment and withdrawal. In 3 of 14 (21.4 %) patients in whom the stent was removed when partially deployed, a sizeable clot in the stent mesh was recovered. In one patient with a preexisting arterial stenosis at the site of occlusion, angioplasty with a Gateway dilatation balloon was attempted.

Emboli in the territory distal to the occluded artery were noted at final angiogram in 10 of 12 (83.3%) patients. Except one embolus in a M2 MCA segment and another in a P2 segment, all the other emboli were in distal convexity pial arteries. We did not note any emboli into a second artery territory due to clot dislodgement during stent retrieval. Eight out of 14 (57.1%) patients had mRS (0–2) at 3 months or discharge with 7 of 14 (50%) achieving a mRS of 0–1. ICH on follow-up CT was noted in 28.6% (4 of 14) patients. The types of ICH noted are as follows: three hemorrhagic infarction (HI-1) and one parenchymal hemorrhage (PH-1) with subarachnoid and intraventricular hemorrhage. All-cause mortality was 2 of 14 (14.3%). No groin complications or device-related complications were noted. We did not note any contrast extravasation during the procedure and think that the subarachnoid hemorrhage in patient 9 is a result of the parenchymal hemorrhage abutting the cortex and the additional intraventricular hemorrhage noted (Table 1).

Illustrative cases

Patient 3: A 41-year-old woman presented to the emergency room with right hemispheric symptoms 2 h after stroke symptom onset. Baseline NCCT showed a hyperdense MCA sign on the right and evolving infarcts in the right temporal lobe, insula, caudate, lentiform, and perisylvian regions (Fig. 1a). CTA revealed a right M1 occlusion (Fig. 1b). Intravenous tPA was given within 155 min of symptom onset. Informed consent was taken from the family for intra-arterial thrombolysis. Preprocedural National Institutes of Health Stroke Scale (NIHSS) was 17. A 6-Fr Strada carotid guiding sheath (St. Jude Medical, Minnetonka, MN) was placed in the proximal right ICA (RICA). Through the Strada, a 6-Fr Neuron was taken up and placed in the distal RICA. Immediate intracranial angiogram revealed an occluded right M1 MCA with no distal flow (Fig. 1c). PROWLER SELECT Plus catheter (Cordis Neurovascular, Inc.) over 0.014-in microwire (Transcend, Boston Scientific/Target Therapeutics) was advanced through the clot and placed in the M2 MCA. After removing the microwire, angiogram through the microcatheter revealed patent M2 branches. The microcatheter was gradually pulled back into the MCA bifurcation. Through the microcatheter, a 4 × 20-mm solitaire stent was taken up and deployed across the occlusion site (Fig. 1d). Instantaneous recanalization of occluded M1 MCA was noted in the control angiogram. The stent was completely resheathed within the microcatheter after 5 min. Control angiogram revealed patent M1 MCA and superior division M2 with an occluded M2 inferior division and slow flow in some distal pial arteries (TIMI 2) (Fig. 1e). No other IA treatment was used. NIHSS at 24 h was 5. Postprocedure CT showed no hemorrhage with some contrast enhancement in the basal ganglia (Fig. 1f). NIHSS at discharge was 1, and mRS at 3 months was 1.
Fig. 1

a NCCT showing early ischemic changes in the caudate (white arrow), lentiform, insula (black arrow), and perisylvian region on the right side. b CT angiogram showing a right M1 MCA occlusion. c Cerebral angiogram in the anteroposterior plane shows a proximal M1 MCA occlusion on the right (TIMI 0). d Retrievable stent deployed in the right M1 MCA segment (white arrow). e Cerebral angiogram after complete retrieval of stent shows good flow into the distal pial arteries (TIMI 2). f Postprocedure NCCT shows no evidence of intracerebral hemorrhage with some contrast enhancement in the basal ganglia

Patient 10: A 79-year-old woman presented to the emergency room with right hemispheric symptoms within an hour of stroke symptom onset. Baseline NCCT shows early ischemic changes in the lentiform nucleus and temporal lobe on the right side (Fig. 2a). CTA revealed a right M1 occlusion. Intravenous tPA was given within 90 min of symptom onset. Informed consent was taken from the family for intra-arterial thrombolysis. Preprocedural NIHSS was 18. A 6-Fr Strada carotid guiding sheath (St. Jude Medical) was placed in the proximal RICA. Through the Strada, a 6-Fr Neuron was taken up and placed in the distal RICA. Immediate intracranial angiogram revealed an occluded right M1 MCA with no distal flow (Fig. 2b). PROWLER SELECT Plus catheter (Cordis Neurovascular, Inc.) over 0.014-in microwire (Transcend, Boston Scientific/Target Therapeutics) was advanced through the clot and placed in the M2 MCA. After removing the microwire, angiogram through the microcatheter revealed patent M2 branches. The microcatheter was gradually pulled back into the MCA bifurcation. Through the microcatheter, a 4 × 20-mm Solitaire FR stent was taken up and deployed across the occlusion site (Fig. 2c). Instantaneous recanalization of occluded M1 MCA was noted in the control angiogram. The stent was left in position for 4 min. Control angiogram revealed patent M1 MCA with excellent flow into the MCA branches (Fig. 2d, e). A small M3 branch showed an embolus. A decision was made not to go after this tiny embolus (Fig. 1e) and superior division M2 with an occluded M2 inferior division and slow flow in some distal pial arteries (TIMI 2) (Fig. 2e). NIHSS at 24 h was 18. Postprocedure NCCT showed evolved infarction in the lentiform and temporal lobe detected in the NCCT at baseline with no evidence of intracerebral hemorrhage (Fig. 2f) and mRS at discharge was 3.
Fig. 2

a NCCT showing early ischemic changes in the lentiform nucleus and temporal lobe on the right side. b Cerebral angiogram in the anteroposterior plane shows a proximal M1 MCA occlusion on the right (TIMI 0). c Retrievable stent deployed in the right M1 MCA segment (black arrow). d and e Cerebral angiogram after retrieval of stent shows good flow into the distal pial arteries (TIMI 2) with an embolus noted in a small temporal branch. f Postprocedure NCCT shows evolved infarction in the lentiform and temporal lobe detected in the NCCT at baseline with no evidence of intracerebral hemorrhage

Discussion

Use of a self-expandable fully retrievable stent in patients with acute ischemic strokes and intracranial occlusions in our series resulted in 85.7% recanalization (TIMI 2–3) and 57.1% good clinical outcome (mRS 0–2) at 3 months or discharge. Parenchymal hemorrhage was noted in 7.1% with all-cause mortality of 14.3%. No significant periprocedural complications were documented.

Consistently high recanalization rates ranging from 75% to 100 % have been reported with the use of stents in acute ischemic stroke (Table 2) [5, 6, 7, 8, 15]. These recanalization rates compare favorably with or are better than that reported with other devices. The Penumbra Pivotal Stroke Trial reports a recanalization rate of 82.5% with use of the “Penumbra” system [4]. We have previously reported similar recanalization rates based on our experience with the “Penumbra” system [16]. Use of a retriever device in the multi Mechanical Embolus Removal in Cerebral Ischemia trial resulted in recanalization rates of 54.5% with the device alone and 69% with adjunctive therapy [17]. In the Prolyse in Acute Cerebral Thromboembolism II study, a recanalization rate of 66% was reported in the treatment arm [18]. The rate of good clinical outcome in our series compares favorably with previous published studies [5, 7, 19].
Table 2

Procedural outcomes and type of stent used in other published series when compared to our series

Study

No. of patients

Recanalization rate

ICH

Periprocedural complications

Stent used

Levy et al. [5]

20

TIMI 2/3, 100%

Symptomatic ICH 5%, asymptomatic ICH 10%

None

Wingspan and Enterprise

Mocco et al. [6]

20

TIMI 2/3, 100%

Symptomatic ICH 10%, asymptomatic ICH 15%

NA

Enterprise

Costano et al. [7]

20

TICI 2b/3, 90%

Symptomatic ICH 10%

None

Solitaire AB

Suh et al. [8]

9

TIMI 2/3, 100%

Asymptomatic ICH 1/9

Two in-stent thrombosis

Enterprise

Roth et al. [19]

22

TICI 2/3, 90.9%

Symptomatic ICH 9.1%, asymptomatic ICH 4.5%

None

Solitaire AB, FR

Our series

14

TIMI 2/3, 85.7%

Symptomatic ICH 7.1%, asymptomatic ICH 21.4%

One in-stent thrombosis

Solitaire AB, FR

NA not available

It is our experience that these self-expanding retrievable stents produce instantaneous occluded artery recanalization and ischemic territory reperfusion by forcing the thrombus against the artery wall when deployed. We noted this phenomenon in 11 of 14 of our patients with first stent deployment. Even though only two patients in our series achieved adequate recanalization (TIMI 2/3) at the end of first stent deployment, by achieving an endovascular bypass in the majority with first deployment albeit temporary and thereby restoring blood flow to the ischemic brain, retrievable stents may help in resetting the ischemic “clock” unlike other mechanical embolectomy devices. The ability to retrieve a significant proportion of thrombus using this technique potentially improves final reperfusion rates. The self-expandable, fully retrievable stent has all the advantages of permanent stenting while avoiding its disadvantages because of its retrievability. Unlike a fully deployed stent, it can be captured and redeployed again if the vessel reoccludes. In situations which warrant permanent deployment, it can also be so deployed. We had to permanently deploy the stent in one patient due to a preexisting arterial stenosis. For a neurointerventionist with experience in stent deployment in situations like carotid disease and stent-assisted aneurysm coiling, familiarity with the technique is an added advantage.

Stenting is not without disadvantages in the setting of acute stroke. In 9 of 11 patients, repeat angiogram after stent resheathing revealed reocclusion of the earlier recanalized segment warranting further passes with the stent. The distal embolization rate (83.3%) in our series is high. Except in two patients, we are, however, unable to confirm whether the distal small emboli were present before the use of the device or whether embolization happened during device use. We do not use flow arrest with a proximal balloon during stent retrieval; this may have contributed to the higher rate of distal embolization in our series. The fact that we did not notice any distal emboli in a second artery territory supports the contention that distal embolization occurs at the time of deployment of the stent due to thrombus fragmentation and is not preventable with flow arrest. Roth et al. in a recent series report a 36.3% Thrombolysis in Cerebral Infarction (TICI) 2a/2b rate when compared to a TICI 3 rate of 54.5% [19]. Though they do not explicitly report distal embolization rates in the same territory, it is quite possible that the rate may be near the TICI 2a/2b rates they report. They report a 30–90-day mRS 0–2 of 50% when compared to a mRS 0–2 of 57.5% and mRS 0–1 of 50% in our series, thus suggesting that the high distal embolization rate in small convexity pial arteries in our series may be clinically inconsequential and due to the fact that we have reported emboli in very small distal pial convexity branches. It has been our practice and belief that a small amount of intra-arterial tPA through a microcatheter aids in subsequent clean up of the distal circulation. Similarly, rapidly proceeding to the neuroangiography suite while intravenous tPA is running may allow intravenous tPA to prevent complications from distal embolization [16].

In-stent thrombosis is a potential complication which may warrant use of antiplatelet agents [20, 21]. We noted this complication during procedure in one patient which resulted in the use of an intra-arterial platelet aggregation inhibitor (abciximab). Permanently deployed intracranial stents require immediate and possibly long-term therapy with multiple antiplatelet agents [22]. In the periprocedural period, the risk of clinically significant parenchymal hemorrhage, particularly when thrombolytic agents have been given, is increased by the addition of antiplatelet agents [23]. We do not, therefore, use antiplatelet agents in the acute setting except when absolutely warranted. We also recommend active surveillance of blood pressure post recanalization to prevent the risk of parenchymal hemorrhage.

Although our study is limited by its small sample size and retrospective nature, it can provide some feasibility and safety indicators to direct a prospective randomized controlled trial of intracranial stents in acute ischemic strokes refractory to current, more established interventional therapy. Our experience with this new technique has been encouraging due to its ease of use and ability to achieve rapid recanalization. In our opinion, this technique has potential to be a reliable alternative option in the endovascular management of acute ischemic stroke.

Notes

Acknowledgments

We acknowledge the contributions of Drs. Shelagh B Coutts, Michael D Hill, Timothy WJ Watson, Eric E Smith, Phil Barber, Peter K Stys, Gary Klein, stroke fellows and residents, and all other members of the Calgary Stroke Program. We also acknowledge the contribution of the neuroradiology and neurosurgery teams at the Foothills Medical Center and technical support from the Seaman Family MR Center.

Conflict of interest

We declare that we have no conflict of interest.

References

  1. 1.
    Rha JH, Saver JL (2007) The impact of recanalization on ischemic stroke outcome: a meta-analysis. Stroke 38(3):967–973PubMedCrossRefGoogle Scholar
  2. 2.
    Khatri P, Abruzzo T, Yeatts SD, Nichols C, Broderick JP, Tomsick TA (2009) Good clinical outcome after ischemic stroke with successful revascularization is time-dependent. Neurology 73(13):1066–1072PubMedCrossRefGoogle Scholar
  3. 3.
    Smith WS (2006) Safety of mechanical thrombectomy and intravenous tissue plasminogen activator in acute ischemic stroke. Results of the multi Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial, part I. AJNR Am J Neuroradiol 27(6):1177–1182PubMedGoogle Scholar
  4. 4.
    Penumbra Pivotal Stroke Trial Investigators (2009) The penumbra pivotal stroke trial: safety and effectiveness of a new generation of mechanical devices for clot removal in intracranial large vessel occlusive disease. Stroke 40(8):2761–2768CrossRefGoogle Scholar
  5. 5.
    Levy EI, Siddiqui AH, Crumlish A et al (2009) First Food and Drug Administration-approved prospective trial of primary intracranial stenting for acute stroke: SARIS (stent-assisted recanalization in acute ischemic stroke). Stroke 40(11):3552–3556PubMedCrossRefGoogle Scholar
  6. 6.
    Mocco J, Hanel RA, Sharma J et al (2010) Use of a vascular reconstruction device to salvage acute ischemic occlusions refractory to traditional endovascular recanalization methods. J Neurosurg 112(3):557–562PubMedCrossRefGoogle Scholar
  7. 7.
    Castano C, Dorado L, Guerrero C et al (2010) Mechanical thrombectomy with the Solitaire AB device in large artery occlusions of the anterior circulation: a pilot study. Stroke 41(8):1836–1840PubMedCrossRefGoogle Scholar
  8. 8.
    Suh SH, Kim BM, Roh HG et al (2010) Self-expanding stent for recanalization of acute embolic or dissecting intracranial artery occlusion. AJNR Am J Neuroradiol 31(3):459–463PubMedCrossRefGoogle Scholar
  9. 9.
    Khatri P, Hill MD, Palesch YY et al (2008) Methodology of the Interventional Management of Stroke III Trial. Int J Stroke 3(2):130–137PubMedCrossRefGoogle Scholar
  10. 10.
    Hill MD, Moy CS, Palesch YY et al (2007) The albumin in acute stroke trial (ALIAS); design and methodology. Int J Stroke 2(3):214–219PubMedCrossRefGoogle Scholar
  11. 11.
    IMS Study Investigators (2004) Combined intravenous and intra-arterial recanalization for acute ischemic stroke: the Interventional Management of Stroke Study. Stroke 35(4):904–911CrossRefGoogle Scholar
  12. 12.
    Hacke W, Kaste M, Fieschi C et al (1998) Randomised double-blind placebo-controlled trial of thrombolytic therapy with intravenous alteplase in acute ischaemic stroke (ECASS II). Second European-Australasian Acute Stroke Study Investigators. Lancet 352(9136):1245–1251PubMedCrossRefGoogle Scholar
  13. 13.
    Demchuk AM, Hill MD, Barber PA, Silver B, Patel SC, Levine SR (2005) Importance of early ischemic computed tomography changes using ASPECTS in NINDS rtPA Stroke Study. Stroke 36(10):2110–2115PubMedCrossRefGoogle Scholar
  14. 14.
    Hill MD, Demchuk AM, Tomsick TA, Palesch YY, Broderick JP (2006) Using the baseline CT scan to select acute stroke patients for IV-IA therapy. AJNR Am J Neuroradiol 27(8):1612–1616PubMedGoogle Scholar
  15. 15.
    Kelly ME, Furlan AJ, Fiorella D (2008) Recanalization of an acute middle cerebral artery occlusion using a self-expanding, reconstrainable, intracranial microstent as a temporary endovascular bypass. Stroke 39(6):1770–1773PubMedCrossRefGoogle Scholar
  16. 16.
    Menon BK, Hill MD, Eesa M et al (2010) Initial experience with the Penumbra Stroke System for recanalization of large vessel occlusions in acute ischemic stroke. Neuroradiology. doi:10.1007/s00234-010-0725-2 Google Scholar
  17. 17.
    Smith WS, Sung G, Saver J et al (2008) Mechanical thrombectomy for acute ischemic stroke: final results of the Multi MERCI trial. Stroke 39(4):1205–1212PubMedCrossRefGoogle Scholar
  18. 18.
    Furlan A, Higashida R, Wechsler L et al (1999) Intra-arterial prourokinase for acute ischemic stroke. The PROACT II study: a randomized controlled trial. Prolyse in Acute Cerebral Thromboembolism. JAMA 282(21):2003–2011PubMedCrossRefGoogle Scholar
  19. 19.
    Roth C, Papanagiotou P, Behnke S et al (2010) Stent-assisted mechanical recanalization for treatment of acute intracerebral artery occlusions. Stroke 41(11):2559–2567PubMedCrossRefGoogle Scholar
  20. 20.
    Zaidat OO, Wolfe T, Hussain SI et al (2008) Interventional acute ischemic stroke therapy with intracranial self-expanding stent. Stroke 39(8):2392–2395PubMedCrossRefGoogle Scholar
  21. 21.
    Riedel CH, Tietke M, Alfke K, Stingele R, Jansen O (2009) Subacute stent thrombosis in intracranial stenting. Stroke 40(4):1310–1314PubMedCrossRefGoogle Scholar
  22. 22.
    Qureshi AI, Feldmann E, Gomez CR et al (2009) Intracranial atherosclerotic disease: an update. Ann Neurol 66(6):730–738PubMedCrossRefGoogle Scholar
  23. 23.
    Uyttenboogaart M, Koch MW, Koopman K, Vroomen PC, De Keyser J, Luijckx GJ (2008) Safety of antiplatelet therapy prior to intravenous thrombolysis in acute ischemic stroke. Arch Neurol 65(5):607–611PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Bijoy K. Menon
    • 1
  • Puneet Kochar
    • 2
  • Andrew Ah-Seng
    • 2
  • Mohammed A. Almekhlafi
    • 1
    • 4
  • Jayesh Modi
    • 2
  • John H. Wong
    • 2
    • 3
  • Mark E. Hudon
    • 2
  • Will Morrish
    • 2
  • Andrew M. Demchuk
    • 1
    • 2
  • Mayank Goyal
    • 2
  1. 1.Department of Clinical NeurosciencesUniversity of CalgaryCalgaryCanada
  2. 2.Department of RadiologyUniversity of CalgaryCalgaryCanada
  3. 3.Department of NeurosurgeryUniversity of CalgaryCalgaryCanada
  4. 4.Department of Internal MedicineKing Abdulaziz UniversityJeddahSaudi Arabia

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