Clinical Outcomes in Middle Cerebral Artery Trunk Occlusions Versus Secondary Division Occlusions After Mechanical Thrombectomy - Semantic Scholar
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Clinical Outcomes in Middle Cerebral Artery Trunk
Occlusions Versus Secondary Division Occlusions After
Mechanical Thrombectomy
Pooled Analysis of the Mechanical Embolus Removal in Cerebral Ischemia
(MERCI) and Multi MERCI Trials
Zhong-Song Shi, MD; Yince Loh, MD; Gary Walker, PhD; Gary R. Duckwiler, MD; for the
MERCI and Multi-MERCI Investigators
Background and Purpose—The benefit of endovascular revascularization of patients with acute ischemic stroke with middle
cerebral artery (MCA) secondary division (M2) occlusions as compared with MCA trunk (M1) occlusions is not known. In
this analysis, we compared revascularization status and clinical outcomes in patients with angiographically confirmed MCA
M1 versus isolated M2 occlusions treated with mechanical thrombectomy using the Merci Retriever devices.
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Methods—We retrospectively analyzed the pooled data of patients with MCA strokes from the Mechanical Embolus
Removal in Cerebral Ischemia (MERCI) and Multi MERCI trials. Patient data were dichotomized into 2 groups: MCA
M1 occlusions and isolated M2 occlusions. Baseline characteristics, revascularization rates, hemorrhage rates,
complications, outcomes, and mortality were evaluated for both groups.
Results—Of 178 patients with MCA occlusion treated in the MERCI and Multi MERCI trials, 84.3% had M1 lesions and
15.7% had isolated M2 lesions. Patients with isolated M2 occlusions were revascularized at a higher rate, required a
lower mean number of passes, and were associated with a trend toward shorter mean procedure time than patients with
M1 occlusions. No statistically significant differences were found between M2 and M1 groups for symptomatic
hemorrhage, clinically significant procedural adverse events, favorable 90-day outcome, or 90-day mortality, although
in all instances, the M2 outcomes were numerically better than those in M1 subjects. In multivariate analysis, final
revascularization was the strongest independent predictor of good outcome at 90 days.
Conclusions—Patients with both MCA M1 occlusions and isolated M2 occlusions can achieve a relatively high rate of
revascularization and favorable clinical outcomes after mechanical thrombectomy. In fact, patients with isolated M2
occlusions had a higher rate of revascularization, required fewer passes, and had no increased complications compared
with patients with M1 occlusions. (Stroke. 2010;41:953-960.)
Key Words: acute stroke 䡲 endovascular treatment 䡲 middle cerebral artery 䡲 outcome 䡲 thrombectomy
P atients with acute ischemic stroke caused by intracranial
large vessel occlusion appear to respond differently to
thrombolysis treatment depending on the occluded vessel site.
stroke population. However, in trials of IV and intra-arterial (IA)
thrombolysis, few have reported the distinction of revasculariza-
tion status and clinical outcomes between MCA trunk (M1) and
In the vital randomized National Institute of Neurological isolated secondary division (M2) occlusions.1– 8 Recent studies
Diseases and Stroke, European Cooperative Acute Stroke using transcranial Doppler ultrasonography and/or CT angiog-
Study (ECASS), and Alteplase Thrombolysis for Acute raphy revealed that the revascularization status of MCA M2
Noninterventional Therapy in Ischemic Stroke trials of intrave- occlusions was superior to that of MCA M1 occlusions after IV
nous (IV) tissue plasminogen activator (tPA), possibly due to tPA treatment.9,10 Patients with MCA M2 occlusions were twice
the lack of accurate assessment of the clot location, neither the as likely to have a favorable clinical outcome as patients with
revascularization status nor clinical outcomes were influenced MCA M1 occlusions.9
by the occluded vessel types.1– 4 Middle cerebral artery (MCA) The Prolyse in Acute Cerebral Thromboembolism (PRO-
territory stroke accounts for the largest proportion of ischemic ACT) II study included 61.7% of patients with MCA M1
Received November 2, 2009; final revision received December 11, 2009; accepted January 19, 2010.
From the Division of Interventional Neuroradiology (Z.S.S., Y.L., G.R.D.), David Geffen School of Medicine at UCLA, Los Angeles, Calif; and
Concentric Medical, Inc (G.W.), Mountain View, Calif.
Current affiliation for Z.S.S.: Department of Neurosurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, P.R.China.
Current affiliation for Y.L.: Neurovascular Service, Department of Medicine, Madigan Army Medical Center, Tacoma, Wash.
Correspondence to Gary R. Duckwiler, MD, Division of Interventional Neuroradiology, David Geffen School of Medicine at UCLA, 757 Westwood
Plaza, Los Angeles, CA 90095-7437. E-mail gduckwiler@mednet.ucla.edu
© 2010 American Heart Association, Inc.
Stroke is available at http://stroke.ahajournals.org DOI: 10.1161/STROKEAHA.109.571943
953954 Stroke May 2010
occlusions, and the remainder presumably had isolated MCA the patient died. Procedure-related adverse events were adjudicated
M2 lesions; however, clinical outcomes stratified by M1 by an independent Data Safety and Monitoring Board and were
defined as vascular perforation, intramural arterial dissection, or
versus M2 occlusions have rarely, if ever, been reported.5
embolization of a previously uninvolved territory, symptomatic
Recent studies of IA thrombolysis with urokinase treatment hemorrhage, and access site complications requiring surgery or
suggest that the revascularization status of MCA M1 occlu- transfusion. Clinically significant procedural complications were
sions was better than that of the isolated M2 occlusions, but defined as a procedure complication with decline in NIHSS of ⱖ4 or
the clinical outcome associated with the different clot lesions death, groin complication requiring surgery, or blood transfusion.
Neurological status was quantified by the NIHSS and modified
was not described.11,12 Rankin Scale (mRS) score at 30 days and 90 days. Patients in each
Mechanical thrombectomy with the Merci devices is a occlusion group were assessed for revascularization rate, hemor-
promising alternative treatment for patients with acute ische- rhagic transformation rate, clinically significant procedure-related
mic stroke who have either failed or are ineligible for IV tPA complications, clinical outcome, and mortality at 90 days. Good
within 8 hours of initial symptom onset.13–17 As demonstrated outcome at 90 days was defined as mRS ⱕ2. Due to the relatively
small sample size of isolated M2 occlusions, the data from M1 and
by the pooled analysis of Mechanical Embolus Removal in M2 occlusions were pooled together and a multivariate logistic
Cerebral Ischemia (MERCI) and Multi MERCI Part I trials, regression analysis was performed to determine the independent
patients with internal carotid artery (ICA) occlusions can predictors of good outcome at 90 days. Further comparisons of
achieve relatively high revascularization rates.17 However, clinical characteristics, complications, and outcomes were stratified
by the revascularization status.
the difference in outcomes between mechanical revascular- For comparisons of differences between groups, a 95% CI was
ization of the MCA M2 occlusion and the MCA M1 occlu- constructed around the difference. If this interval did not contain
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sion was not assessed. The purpose of this study was to zero, the difference was considered significant at the P⫽0.05 level.
evaluate whether angiographically confirmed MCA M1 ver- Although this is a retrospective subset analysis, sample sizes for the
sus isolated M2 occlusion influences the revascularization 2 groups allowed for at least 80% power of detecting a 28% absolute
difference and at least 50% power for detecting a 20% absolute
status and subsequent clinical outcomes among patients with difference between groups in outcome rates. Univariable analyses
acute ischemic stroke treated by mechanical thrombectomy were separately performed to identify independent predictors of good
with the Merci family of retriever devices. The safety and outcome at 90 days. All variables with Wald 2 P⬍0.2 in univariable
effectiveness of mechanical thrombectomy in all MCA oc- analysis as independent variables were included in the multivariable
logistic regression model-building process to identify predictors for
clusions were also compared between groups (M1 versus M2)
good outcome at 90 days. The model was built using forward/
by revascularization status. backward stepwise regression with variables entered at the 0.05
significance level and removed at the 0.10 significance level based
Methods on the 2 statistic. After the main effects model was established, the
Pooled data from the MERCI and Multi MERCI trials were retro- hypothesis for the presence of any significant 2-way interaction
spectively analyzed for identification of acute MCA strokes. The terms was tested with the likelihood ratio 2 (G2) statistic. The final
pooled data consisted of a total of 305 patients with ischemic stroke, model was then assessed for goodness of fit with the Hosmer and
141 patients from MERCI and 164 patients from Multi MERCI. The Lemeshow test. P⬍0.05 was considered statistically significant.
protocol details of these 2 trials have been previously described.13–17 Statistical analyses were performed using SAS software (Version
Briefly, enrolled patients were either ineligible for IV tPA or the 8.2; SAS Institute Inc).
occluded vessel failed to open after receiving IV tPA as confirmed
by catheter angiography. A family of X series and L5 Merci Results
Retriever devices (Concentric Medical, Inc, Mountain View, Calif)
was used to attempt to restore the occluded intracranial vessel by Demographic Characteristics of Patients With
retracting the clot from the vessel lumen. The first-generation MCA Stroke
devices (X4, X5, and X6 Retrievers) were available in both trials. One hundred seventy-eight patients with an angiographically
The second-generation devices (L5 Retriever) were only used in confirmed MCA occlusion were treated in the MERCI and
Multi MERCI. IA fibrinolysis with tPA was allowed in cases of Multi MERCI trials. Of these, 80 were enrolled in MERCI
treatment failure with the device after 6 passes or to treat distal
emboli not accessible to the device after successful proximal and 98 were enrolled in Multi MERCI. The mean age was
thrombectomy. Angioplasty and stenting of any lesion were not 69.0 (SD 15.7) years and 103 (57.9%) were women. The
allowed per protocol. mean baseline NIHSS score was 18.8 (SD 5.8) points (range,
Patients who had isolated MCA M1 and/or M2 occlusions 9 to 40). Twenty-seven (15.2%) patients in this cohort
confirmed by digital subtraction angiography were included in this received IV tPA and failed to recanalize before mechanical
study. The patients with ICA/MCA tandem or ICA-T occlusions
were excluded from this analysis. The resulting patients were embolectomy; the remaining 151 patients were ineligible for
hierarchically dichotomized into 2 groups: an MCA M1 occlusion IV tPA. Mean time from stroke onset to arterial access was
group and an isolated MCA M2 occlusion group. Successful revas- 4.3 (SD 1.6) hours (range, 0.7 to 10.8 hours).
cularization was defined as achieving Thrombolysis In Myocardial Among the 178 patients, 84.3% (n⫽150) presented with an
Infarction (TIMI) II or III flow in all treatable vessels as confirmed isolated MCA M1 occlusion or with a combined M1/M2
by posttreatment digital subtraction angiogram. CT or MRI brain
imaging was performed at baseline, 24 hours, and at any time there occlusion, and 15.7% (n⫽28) presented with an isolated
was a decline in patient neurological status. Intracerebral hemor- MCA M2 occlusion. Among the 150 patients with MCA M1
rhages were categorized as hemorrhagic infarction Type I and II or occlusion, 73 were enrolled in MERCI and 77 were enrolled
parenchymal hematoma Types I and II according to the classifica- in Multi MERCI. Among the 28 patients with MCA M2
tions of the ECASS trial. Symptomatic hemorrhage was defined as a occlusion, 7 were enrolled in MERCI and 21 were enrolled in
ⱖ4-point increase in the National Institutes of Health Stroke Scale
(NIHSS) score within 24 hours with evidence of any blood identified Multi MERCI. Baseline characteristics, including age, gen-
on 24-hour head CT/MRI scan or any intracranial hemorrhage in der, NIHSS score, time from symptom onset to arterial
which no further NIHSS scores were available beyond baseline and access, and adjunctive tPA use, were not significantly differ-Shi et al Outcomes in MCA Occlusions With the Merci Retriever 955
Table 1. Patient Characteristics by Occlusion Location
Total MCA M1 MCA M2
(n⫽178) (n⫽150) (n⫽28) P*
Age, median years (IQR) 73.0 (60.0 to 80.0) (178) 73.0 (60.0 to 80.0) (150) 71.5 (61.5 to 81.0) (28) 0.94
Female 57.9% (103/178) 56.0% (84/150) 67.9% (19/28) 0.30
Hypertension 77.5% (138/178) 77.3% (116/150) 78.6% (22/28) ⬎0.99
Diabetes mellitus 24.8 (44/177) 25.0% (37/149) 24.9% (7/28) 0.99
Dyslipidemia 34.8% (57/164) 34.1% (47/138) 38.5% (10/26) 0.67
Coronary artery disease 39.7% (69/174) 43.2% (63/146) 21.4% (6/28) 0.04
Congestive heart failure 21.6% (38/176) 22.3% (33/148) 17.9% (5/28) 0.59
Smoking 18.4% (30/163) 19.6% (27/138) 12.0% (3/25) 0.35
Atrial fibrillation 44.1% (78/177) 41.6% (62/149) 57.1% (16/28) 0.15
Hematologic disorder 6.3% (11/174) 6.2% (9/146) 7.1% (2/28) 0.85
Peripheral vascular disorder 12.1% (21/173) 13.1% (19/145) 7.1% (2/28) 0.35
Glucose, mg/dL 134.2⫾51.4 (176) 134.6⫾51.8 (149) 132.1⫾49.9 (27) 0.82
Prothrombin time, seconds 13.4⫾4.4 (170) 13.1⫾3.2 (143) 15.1⫾8.1 (27) 0.03
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Activated partial thromboplastin time, seconds 30.1⫾17.8 (160) 30.2⫾19.1 (134) 29.3⫾8.6 (26) 0.8
International normalized ratio 1.21⫾0.49 (174) 1.18⫾0.42 (148) 1.34⫾0.8 (26) 0.13
Platelet (count) 240.4⫾77.2 (175) 238.4⫾77.5 (148) 251.4⫾75.4 (27) 0.42
Systolic blood pressure median, mm Hg (IQR) 150.0 (131 to 165) (176) 147.0 (130 to 163) (149) 157.0 (132 to 176) (27) 0.08
Diastolic blood pressure median, mm Hg (IQR) 75.5 (64 to 85) (176) 74.0 (62 to 84) (149) 80.0 (68 to 91) (27) 0.09
Baseline NIHSS, median (IQR) 18.0 (14 to 23) (178) 18.0 (15 to 23) (150) 17.0 (14 to 22) (28) 0.56
Left-sided MCA occlusion 50.6% (90/178) 47.3% (71/150) 67.9% (19/28) 0.06
Symptom onset to groin puncture, median hours (IQR) 4.3 (3.2 to 5.4) (177) 4.2 (3.2 to 5.5) (149) 4.7 (3.7 to 5.3) (28) 0.35
Failed IV tPA pre-Merci 15.2% (27/178) 14.0% (21/150) 21.4% (6/28) 0.33
IA lytic use 32.0% (57/178) 30.7% (46/150) 39.3% (11/28) 0.38
IV or IA lytic use 41.6% (74/178) 40.0% (60/150) 50.0% (14/28) 0.33
IV and IA lytic use 5.6% (10/178) 4.7% (7/150) 10.7% (3/28) 0.19
White race 84.8% (151/178) 82.7% (121/150) 96.4% (27/28) 0.05
*P values computed using 2-sample Wilcoxon test for continuous variables and Fisher exact test for categorical variables.
IQR indicates interquartile range.
ent between patients in each group. Patients with MCA M1 occlusions, isolated MCA M2 occlusions were revascularized
occlusion were more likely to have coronary artery disease, a in fewer passes (2.1 versus 3.1) and trended toward quicker
lower prothrombin time, and lower systolic blood pressure mean procedure times (1.6 versus 1.8 hours).
(Table 1). In the M1 cohort, the X6 and L5 devices were used
most frequently (44.7% for each) with the X5 (34.0%) and X4 Good Outcome and Mortality
(6.7%) being less common. In the M2 cohort, the L5 device Favorable clinical outcomes at 90 days (mRS ⱕ2) were not
was most commonly used (53.6%) followed by the X6 significantly different between the 2 groups (Table 2), al-
(28.6%) and the X5 (25.0%). The X4 was not used in the M2 though there was a numerically higher frequency of good
cohort. In both groups, 7% of patients were sedated at the outcomes in the isolated MCA M2 occlusion group than the
time their baseline NIHSS was assessed. There was no MCA M1 occlusion group (40.7% versus 33.3%). Although
significant difference in the motor score elements of the better outcomes might be expected with more distal occlu-
NIHSS between the cohorts, although there was a noticeably sions in general, in this series, M2 occlusions were left-sided
higher rate of severe or global aphasia in the M2 cohort in 67.9% versus M1 occlusions being only 47.3% left-sided.
(73.1%) as compared with the M1 cohort (52.5%). Mortality rates at 90 days were not significantly different
between groups; however, it was numerically lower in the
Revascularization Rates isolated MCA M2 occlusion group than in the MCA M1
Overall rates of revascularization (TIMI II/III flow) immedi- occlusion group (25.9% versus 32.9%; Table 2).
ately after Merci treatment alone were 46.0% and 71.4% in
the MCA M1 group and isolated M2 group, respectively Hemorrhage Complication
(Table 2). The final revascularization rate for patients, includ- Intracranial hemorrhage rates were not statistically different
ing those who received adjunctive therapy, was higher in the between groups (36.7% in the M1 group versus 42.9% in the
isolated MCA M2 group than the MCA M1 group (82.1% M2 group). Symptomatic hemorrhage rates were not statisti-
versus 60.0%). In addition, compared with the MCA M1 cally different between groups (3.6% in the M2 group versus956 Stroke May 2010
Table 2. Revascularization and Clinical Outcomes by Occlusion Location
Total MCA M1 MCA M2
(n⫽178) (n⫽150) (n⫽28) P*
Procedure duration, median hours (IQR) 1.6 (0.3 to 4.7)(173) 1.7 (0.3 to 4.7) (149) 1.5 (0.8 to 2.8) (28) 0.19
Attempts to remove clot 2.96⫾1.56 3.12⫾1.55 2.11⫾1.31 0.001
TIMI II/III flow postretriever 50.0% (89/178) 46.0% (69/150) 71.4% (20/28) 0.02
Final TIMI II/III flow 63.5% (113/178) 60.0% (90/150) 82.1% (23/28) 0.03
Clinically significant procedure adverse events 5.1% (9/178) 5.3% (8/150) 3.6% (1/28) ⬎0.99
NIHSS score improvement ⱖ10 points at 24 hours 20.4% (33/162) 19.9% (27/136) 23.1% (6/26) 0.79
mRS ⱕ2 at 90 days 34.5% (57/165) 33.3% (46/138) 40.7% (11/27) 0.51
Mortality at 90 days 31.8% (55/173) 32.9% (48/146) 25.9% (7/27) 0.65
Intracranial hemorrhage 37.6% (67/178) 36.7% (55/150) 42.9% (12/28) 0.53
Asymptomatic hemorrhage 31.5% (56/178) 30.0% (45/150) 39.3% (11/28) 0.38
Symptomatic hemorrhage 6.2% (11/178) 6.7% (10/150) 3.6% (1/28) ⬎0.99
*P values computed using 2-sample Wilcoxon test for continuous variables and Fisher exact test for categorical variables.
IQR indicates interquartile range.
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6.7% in the M1 group). The patients with M2 occlusion had high revascularization rates and favorable clinical outcomes
a numerically lower percentage of clinically significant after mechanical thrombectomy with the Merci devices.
procedure-related adverse events than the patients with M1 Patients with isolated M2 occlusions achieved a higher
occlusion (3.6% versus 5.3%). revascularization rate and were associated with a trend of a
shorter median procedure time.
Multivariate Logistic Regression Analysis Increasing evidence shows that revascularization rates and
Similar to prior MERCI trials analysis, age, baseline NIHSS, good clinical outcomes may be significantly impacted by the
and revascularization status postprocedure were all predictors vessel occlusion location. In the IV and IA thrombolysis
of good clinical outcomes at 90 days. The results are shown studies, MCA occlusions were more likely to respond to
in Table 3. Final revascularization status was the strongest thrombolytic treatment than ICA and basilar artery occlu-
independent predictor of good outcomes with an OR of 30.91.
sions.9,11 Compared with the previous analyses from the
MERCI and Multi MERCI trials, the 60% revascularization
Comparison Between Revascularized and
Nonrevascularized Patients rate in the MCA M1 group was similar to the 63% revascu-
In all MCA occlusions, the revascularized patients had a larization rate of ICA occlusions and lower than the 78%
higher rate of good 90-day outcomes, a lower rate of revascularization rate of vertebrobasilar artery occlusions
mortality and symptomatic hemorrhage, and had fewer passes treated with mechanical thrombectomy.17,18 The 82% revas-
and a shorter procedure time compared with the nonrevascu- cularization rate in the isolated MCA M2 occlusions was
larized patients (Table 4). Baseline characteristics, including significantly higher than other sites of occlusions.17,18
age and NIHSS score, risk factors, and laboratory findings on The 63.5% revascularization rate after mechanical throm-
admission were similar in patients with and without final bectomy for MCA occlusions observed in this study was
revascularization postprocedure. higher than for patients treated with IV thrombolysis alone in
other trials. In 1 study, transcranial Doppler-proven sponta-
Discussion neous recanalization within 6 hours of symptom onset oc-
Results from this study suggest that patients presenting with curred in 18% of the patients with MCA cardioembolic
MCA M1 occlusions or isolated M2 occlusions can achieve occlusions.19 In the PROACT II study, angiographically
confirmed spontaneous recanalization at 6 to 8 hours after
Table 3. Multivariate Predictors of Good Outcome (mRS 0 –2) stroke onset occurred in approximately 18% of the placebo
at 90 days (pooled M1 and M2) patients with acute MCA occlusion after receiving intrave-
Categorical OR nous heparin.5 In another series of 82 patients with MCA
Variable Comparison 关95% CI兴 P* main stem occlusions studied with MR angiography, based on
Final Yes versus no 30.91 关7.82 to ⬎99.99兴 ⬍0.0001 TIMI flow grade, there was a higher spontaneous recanalization
revascularization rate at 24 hours after symptom onset in the IV thrombolysis
Baseline NIHSS Continuous 0.83 关0.75 to 0.91兴 ⬍0.0001 group compared with the no IV thrombolysis control group.20
score The rates of partial and complete recanalization (TIMI II and III)
Age, years Continuous 0.96 关0.93 to 0.99兴 0.0073 were 38.5% in the IV thrombolysis group and 24% in the no IV
Hemorrhage Yes versus no 0.31 关0.12 to 0.81兴 0.0145 thrombolysis group, respectively.20
Although the distinction of revascularization status be-
*Likelihood ratio 2 test on the G2 statistic: P⫽0.09 (conclusion: do not
reject hypothesis that the coefficients for all 2-way interaction terms are zero). tween MCA M1 and isolated M2 occlusions was not reported
Hosmer and Lemeshow goodness-of-fit test: P⫽0.83 (conclusion: do not reject in the published data from the IV thrombolysis trials, the
hypothesis that model fits the data). superiority of revascularization in the isolated MCA M2Shi et al Outcomes in MCA Occlusions With the Merci Retriever 957
Table 4. Comparison Between Patients Who Revascularized and Those Who Did Not
Revascularized Nonrevascularized
(n⫽113) (n⫽65) P*
Age, median years (IQR) 73.0 (62.0 to 81.0) (113) 72.0 (59.0 to 80.0) (65) 0.47
Female 54.9% (62/113) 63.1% (41/65) 0.34
Hypertension 75.2% (85/113) 81.5% (53/65) 0.36
Diabetes mellitus 28.6% (32/112) 18.5% (12/65) 0.15
Dyslipidemia 34.6% (37/107) 35.1% (20/57) ⬎0.99
Coronary artery disease 45.5% (51/112) 29.0% (18/62) 0.04
Congestive heart failure 21.6% (24/111) 21.5% (14/65) ⬎0.99
Smoking 17.9% (19/106) 19.3% (11/57) 0.84
Atrial fibrillation 40.7% (46/113) 50.0% (32/64) 0.27
Hematologic disorder 6.4% (7/110) 6.3% (4/64) ⬎0.99
Peripheral vascular disorder 11.8% (13/110) 12.7% (8/63) ⬎0.99
Glucose, median, mg/dL (IQR) 119.0 (105 to 146) (113) 118.0 (103 to 143) (63) 0.56
Systolic blood pressure, median, mm Hg (IQR) 143.0 (130 to 166) (112) 152.5 (138 to 164) (64) 0.21
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Diastolic blood pressure, median, mm Hg (IQR) 74.0 (63 to 82) (112) 77.0 (65 to 89) (64) 0.23
Baseline NIHSS, median (IQR) 17.0 (14 to 22) (113) 19.0 (15 to 23) (65) 0.18
Left-sided MCA occlusion 52.2% (59/113) 47.7% (31/65) 0.64
Symptom onset to groin puncture, median hours (IQR) 4.1 (3.1 to 5.3) 4.5 (3.5 to 5.6) 0.19
Failed IV tPA pre-Merci 17.7% (20/113) 10.8% (7/65) 0.28
IA lytic use 37.2% (42/113) 23.1% (15/65) 0.07
IV or IA lytic use 46.9% (53/113) 32.3% (21/65) 0.06
White race 85.8% (97/113) 83.1% (54/65) 0.67
Procedure duration, median hours (IQR) 1.6 (1.0 to 2.1) 1.8 (1.5 to 2.6) 0.002
Attempts to remove clot, median (IQR) 2.0 (1 to 3) 4.0 (3 to 5) ⬍0.001
Procedural complications 8.0% (9/113) 16.9% (11/65) 0.09
Clinically significant procedure adverse events 2.7% (3/113) 9.2% (6/65) 0.08
mRS ⱕ2 at 90 days 51.9% (54/104) 4.9% (3/61) ⬍0.001
Mortality at 90 days 22.0% (24/109) 48.4% (31/64) ⬍0.001
Symptomatic hemorrhage 2.7% (3/113) 12.3% (8/65) 0.02
*P values computed using 2-sample Wilcoxon test for continuous variables and Fisher exact test for categorical variables.
IQR indicates interquartile range.
occlusions over the M1 occlusions in our study is consistent PROACT II), 90-day good outcomes (34.5% versus 40%)
with 2 recent studies of IV thrombolysis.9,10 Based on and mortality (31.8% versus 25%), and a lower rate of
transcranial Doppler criteria, complete recanalization up to 2 symptomatic hemorrhage (6.2% versus 10.0%), although the
hours after IV tPA treatment was achieved in 44.2% (50 of median baseline NIHSS score and mean age were higher in
113 patients) and 30% (49 of 163 patients) in the MCA M2 our cohort than in PROACT II (baseline NIHSS: 18 versus
and M1 occlusions, respectively.9 In another study with CT 17; age: 69 years versus 64 years).5 A comprehensive
angiography and/or transcranial Doppler monitoring up to 24 comparison of the data from MERCI/Multi MERCI data and
hours after administration of IV tPA, patients with M1 PROACT is contained in a recent study.21 In a series of 100
occlusions (n⫽32) had 53% complete recanalization, whereas patients with MCA occlusion treated with IA thrombolysis
patients with M2 occlusions (n⫽19) had 68% complete with urokinase, angiography showed MCA M1 occlusion in
recanalization.10 The comparison of recanalization rates be- 57 patients, M2 occlusion in 21, and M3 or M4 occlusion in
tween IV tPA followed by thrombectomy and thrombectomy 22. A higher recanalization rate (76%), a better 90-day good
alone was beyond our current study. IV tPA treatment before outcome (68%), a lower mortality rate (10%), and a similar
thrombectomy may soften the clot, facilitating clot penetra- symptomatic hemorrhage rate (7%) were reported in all MCA
tion and retrieval with Merci devices. The potential benefit of occlusions in this study compared with those in our cohort.22
recanalization induced by the combined therapy of IV tPA The good outcome may be associated with the low stroke
followed by mechanical thrombectomy in the different site score at admission (median baseline NIHSS, 14) and younger
arterial occlusions should be addressed in future studies. age (mean age, 61 years) in this study.
Compared with the 121 treated patients in the PROACT II In the IA thrombolysis studies, revascularization was
study, the patients in our cohort had similar rates of revascu- documented angiographically in patients with MCA strokes;
larization (63.5% in MERCI/Multi MERCI versus 66% in however, the revascularization status and clinical outcomes958 Stroke May 2010
stratified by the MCA M1 occlusions versus isolated M2 analysis. The sample size of patients with M2 occlusion
occlusions were not reported in these randomized clinical enrolled into these 2 trials was smaller than that of the
trials.5,8 In a large series of patients with stroke treated with patients with M1 occlusion. Due to the fact that most of the
IA thrombolysis with urokinase, revascularization rate (TIMI patients with M2 occlusion were collected from the Multi
II and III) was reported in 77.6% of 147 patients with MCA MERCI trial, the better outcomes in the M2 occlusion group
M1 occlusions, whereas a 63.2% revascularization occurred may result from an incorporation of knowledge gained from
in 57 patients with M2 occlusions.11 The lower rate of the practitioner’s increasing experiences and the newer gen-
revascularization in isolated M2 occlusions compared with eration of Merci Retriever devices available in Multi MERCI.
M1 occlusions differed from the results in our cohort. It is not Case selection may be biased. Baseline stroke severity was
clear if this difference was associated with the different comparable in 2 groups, suggesting only patients with MCA
endovascular regimens for IA thrombolysis and mechanical M2 occlusion with severe neurological deficit were enrolled
thrombectomy. in 2 trials. The MCA M2 occlusion group may have included
The data from this study further support the correlation patients with large ischemic lesions at baseline or patients
between successful revascularization and the achievement of with initial MCA M1 or ever ICA/MCA tandem or ICA
good clinical outcomes at 90 days postthrombectomy inter- terminus occlusions who experienced IV tPA- or
vention. We found that successful revascularization was spontaneous-induced recanalization with futile reperfusion.
associated with a higher benefit–risk ratio in both M1 and This may explain the comparable clinical outcome at 3
isolated M2 occlusions. There was a trend of better clinical months rather than simply the imbalance in the side of stroke
outcomes in patients with isolated M2 occlusions than in
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among groups. Finally, the distribution of baseline antithrom-
those with M1 occlusions. This beneficial effect on the botic use was not available from MERCI or Multi MERCI
isolated M2 lesions was also demonstrated by a transcranial and could not be analyzed.
Doppler study in a large series of patients who underwent IV In conclusion, results from this retrospective analysis of
tPA thrombolysis.9 The pooled data from Interventional pooled data of MERCI and Multi MERCI trials suggest that
Management of Stroke I and II trials showed that favorable patients with isolated MCA M2 occlusions may benefit from
clinical outcome in patients with isolated M2 occlusions was a higher rate of revascularization and require fewer passes
independent of the revascularization status because a percent- with Merci Retriever devices to recanalize when compared
age of patients with M2 occlusions achieved good clinical with patients with MCA M1 occlusions. Furthermore, based
outcomes despite incomplete recanalization and reperfu- on a multivariate analysis using the pooled data from patients
sion.6,7,23 It is not clear if the trend toward better clinical with MCA occlusions, it has been demonstrated that final
outcomes in patients with isolated M2 occlusions is associ- revascularization is the strongest predictor of good outcomes
ated with a higher revascularization rate or with a smaller at 90 days postprocedure.
ischemic area at risk. It is speculated that the relatively
greater extent of collateral blood flow in M2 versus M1 Appendix 1: MERCI Trial Investigators
occlusions is a potential factor in the likelihood of a given National Principal Investigator: Wade S. Smith, MD, PhD, Univer-
patient achieving a good clinical outcome. Although there sity of California, San Francisco.
was a trend for better outcomes in the M2 group versus the Data Safety Monitoring Board: Chair: Gene Sung, MD, University
of Southern California; Biostatistician: Phil Hormel, MS; Members:
M1 group, this difference was probably minimized by the Tim W. Malisch, MD, University of Illinois at Chicago; Steven L.
greater frequency of left-sided occlusions in the M2 group Giannotta, MD, University of Southern California; Steven Rudolph,
(67.9% versus 47.3%). Entry criteria for the study necessarily MD, Lenox Hill Hospital; and Fady T. Charbel, MD, University of
mandated high baseline NIHSS and therefore dominant hemi- Illinois at Chicago.
sphere M2 occlusions were more likely to be enrolled. Imaging Core Laboratory: Paul Kim, MD, University of Southern
California.
Anecdotal case reports suggested that the occluded M2 Writing Committee: Ronald Budzik, MD; Y. Pierre Gobin, MD;
branches can be reopened by mechanical therapy using Thomas Grobelny, MD; Randall T. Higashida, MD; Chelsea Kid-
microsnare or Attracter-18 devices if they failed to open with well, MD; Helmi L. Lutsep, MD; Michael Marks, MD; Gary Nesbit,
IA thrombolysis.24,25 However, these devices are not cur- MD; Marilyn M. Rymer, MD; Jeffrey Saver, MD; Isaac E. Silver-
rently recommended for restoring blood flow in large intra- man, MD; Wade S. Smith, MD, PhD; Sidney Starkman, MD; and
Gene Sung, MD.
cranial arteries. Recently, another therapeutic tool to remove Site Principal Investigator (PI), coinvestigators, and Study Coor-
clots from the large intracranial arteries in patients with dinators in order of enrollment (N): University of California at Los
ischemic stroke, the Penumbra System, was cleared by the Angeles Medical Center (22): PI: Sidney Starkman, MD; Gary
US Food and Drug Administration.26 This endovascular Duckwiler, MD; Megan Leary, MD; Chelsea Kidwell, MD; Jeffrey
revascularization therapy may also benefit patients with Saver, MD; Fernando Vinuela, MD; Reza Jahan, MD; Y. Pierre
Gobin, MD; and Judy Guzy, RN. Oregon Health Science University
stroke; however, its efficacy for isolated M2 strokes as well (22): PI: Helmi Lutsep, MD; Stanley Barnwell, MD; Wayne Clark,
as M1 strokes is not yet clearly reported. In addition, the MD; Ted Lowenkopf, MD; Elizabeth North, MD; Joseph Quinn,
intracranial placement of self-expanding stents may be an MD; Robert Egan, MD; Todd Kuether, MD; John Roll, MD; George
alternative option for revascularization of acute MCA M1 Luh, MD; Gary Nesbit, MD; and Barbara Dugan, RN. St Luke’s
occlusions, but its use in the isolated MCA M2 stroke may be Hospital (21): PI: Thomas Grobelny, MD; Naveed Akhtar, MD;
Steven Arkin, MD; Irene Bettinger, MD; Marilyn Rymer, MD;
limited.27 Charles Weinstein, MD; Michael Schwartzman, MD; Christine
This study has several limitations. Data were retrospec- Boutwell, MD; and Barbara Gruenenfelder, RN. Massachusetts
tively collected from 2 single-arm trials with a post hoc General Hospital (11): PI: Walter Koroshetz, MD; Johnny Pryor,Shi et al Outcomes in MCA Occlusions With the Merci Retriever 959
MD; Neeraj Badjatia, MD; Ferdinando Buonarmo, MD; Lawrence Appendix 2: Multi MERCI Trial Investigators
Conrad, MD; David Greer, MD; Raul Nogueira, MD; James Rabi- International Principal Investigator: Wade S. Smith, MD, PhD,
nov, MD; Guy Rordorf, MD; Jonathan Rosand, MD; Lee Schwamm, University of California, San Francisco.
MD; John Sims, MD; Eric Smith, MD; Brian Hoh, MD; Joshua Data Safety Monitoring Board: Chair: Gene Sung, MD, MPH,
Hirsch, MD; Cenk Ayata, MD; Leigh Hochberg, MD; and Joanie University of Southern California. Biostatistician: Phil Hormel, MS.
Cacciola, RN. NY Presbyterian Hospital–Columbia (11): PI: John Members: Tim W. Malisch, MD, Alexian Brothers Medical Center;
Pile-Spellman, MD; Sean Lavine, MD; Sundeep Mangla, MD; Philip Steven Rudolph, MD, Maimonides Medical Center; and Arun Amar,
Meyers, MD; and Leslie Schmidt, NP. The Stroke Center at Hartford MD, Stanford University.
Hospital (11): PI: Isaac Silverman, MD; Stephen Ohki, MD; Gary Imaging Core Laboratory: Paul Kim, MD, University of Southern
Speigel, MD; Martha Ahlquist, LPN, CCRP; and Dawn Beland, California.
MSN. NY Presbyterian Hospital–Cornell (6): PI: Alan Segal, MD; Biostatistician: Phil Hormel, MS.
Ai-His Liu, MD; Igor Ougrets, MD; Howard Riina, MD; Y. Pierre Writing Committee: Ronald Budzik, MD; Gary Duckwiler, MD;
Gobin, MD; and Kimberly Salvaggio, NP. University of California at Donald Frei, MD; Y. Pierre Gobin, MD; Thomas Grobelny,
San Francisco Medical Center (6): PI: Randall Higashida, MD; MD; Randall T. Higashida; Frank Hellinger, MD; Dan Huddle, MD,
Christopher Dowd, MD; Van Halbach, MD; Vineeta Singh, MD; MD; Chelsea Kidwell, MD; Walter Koroshetz, MD; David S.
Nerissa Ko, MD; Jacob Elkins, MD; S. Claiborne Johnston, Liebeskind, MD; Helmi L. Lutsep, MD; Michael Marks, MD; Gary
MD, PhD; J. Claude Hemphill, MD, MSc; David C. Bonovich, MD; Nesbit, MD; Marilyn M. Rymer, MD; Jeffrey Saver, MD; Isaac E.
Sharon Filler, RN; and Melissa Meighan, RN. Florida Hospital Silverman, MD; Wade S. Smith, MD, PhD; Sidney Starkman, MD;
Neuroscience Institute (5): PI: Frank Huang-Hellinger, MD; Susan and Gene Sung, MD, MPH.
Mitchell, RN. Riverside Methodist Hospital (5): PI: Ronald Budzik, Site Principal Investigator (PI), coinvestigators, and Study Coor-
MD; Geoffrey Eubank, MD; Erik Arce, MD; Jim Fulop, MD; John dinators in order of number of patients treated (N): St Luke’s
Lippert, MD; Tom Davis, MD; J. Kevin McGraw, MD; Peter Pema, Hospital (50): Co-PIs: Naveed Akhtar, MD, and Thomas Grobelny,
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MD; and Paula Meyers, RN. Stanford University Medical Center (5): MD; Annette Allen, RN; Steven Arkin, MD; Irene Bettinger, MD;
Christine Boutwell, MD; Charlene Grau, RN; Barbara Gruenen-
PI: Michael Marks, MD; Huy Do, MD; Gregory Albers, MD; Amie
felder, RN; Marilyn Rymer, MD; Michael Schwartzman, MD; and
Hsia, MD; David Tong, MD; Christine Wijamn, MD; and Mary
Charles Weinstein, MD. Riverside Methodist Hospital (32): PI:
Marcellus, RN. Carolina Neurosurgery and Spine (4): PI: Joseph
Ronald Budzik, MD; Erik Arce, MD; Albert Berarducci, MD; Tom
Bernard, MD; Gary DeFilipp, MD; Richard Bellon, MD; Barry Davis, MD; Mark Dean, MD; Eric Dolen; Geoffrey Eubank, MD;
McGinnis, MD; Andrea Dietrich, MD; Steve Putnam, MD; and Jim Fulop, MD; Xiamei Gao-Hickman, MD; John Lippert, MD;
Peggy Boltes, RN. Georgetown University (2): PI: Vance Watson, William Mayr, MD; J. Kevin McGraw, MD; Paula Meyers, RN;
MD; John DeSimone, MD; Manual Yepes, MD; and Theresa Kowal, Peter Pema, MD; and Robert Wyatt, MD. Oregon Stroke Center
RN. University of Maryland (2): PI: Joanne Stallmeyer, MD; (21): PI: Helmi Lutsep, MD; Stanley Barnwell, MD; Wayne Clark,
Abraham Obuchowski, MD; Greg Zoarski, MD; Marian LaMonte, MD; Barbara Dugan, RN; Robert Egan, MD; Todd Kuether, MD;
MD; Marcella Wozniack, MD; and Deborah Schofield, RN. Univer- Ted Lowenkopf, MD; Gary Nesbit, MD; Elizabeth North, MD;
sity of Pennsylvania (2): PI: David Liebeskind, MD; Scott Kasner, Bryan Peterson, MD; John Roll, MD; and Lisa Yanase, MD. The
MD; Brett Cucchiara, MD; Steven Messe, MD; Robert Taylor, MD; Stroke Center at Hartford Hospital (14): PI: Isaac Silverman, MD;
Michael McGarvey, MD; Robert Hurst, MD; Linda Bagley, MD; Martha Ahlquist, LPN, CCRP; Dawn Beland, MSN; Joao Gomes,
John Weigele, MD; and Jessica Clarke, RN, BSN. Brigham and MD; Stephen Ohki, MD; and Gary Speigel, MD. University of
Women’s Hospital (1): PI: Walter Koroshetz, MD; Kai Frerichs, California at Los Angeles Medical Center (12): PI: Sidney Starkman,
MD; Steven Feske, MD; Alexander Norbash, MD; Galen Hendersen, MD; Latisha Ali; Brian Buck, MD; Dennis Chute, MD; Gary
MD; Farzanah Sorond, MD; John Baker, MD; Peng Chen, MD; and Duckwiler, MD; Judy Guzy, RN; Reza Jahan, MD; Doojin Kim,
Joanne O’Hara, RN. Latter-Day Saints Hospital (1): PI: John Jacobs, MD; David S. Liebeskind, MD; Victor Marder, MD; Bruce
MD; Lisa Yananse, MD; Duane Blatter, MD; Albert Lee Bahr, MD; Ovbiagele, MD; Venkatakrishna Rajajee, MD; Lucas Restrepo, MD;
Collen Harker MD; David Pisani, MD; and Kathy Walker, RN. Nerses Sanossian, MD; Jeffrey Saver, MD; Scott Selco, MD; Samir
Louisiana State University at Shreveport (1): PI: Claudio Schono- Shah, MD; Maria Shukman, RN; Satoshi Tateshima, MD; Amytis
holz, MD; Horacio D’Agostino, MD; Anil Nanda, MD; Roger Towfighi, MD; Paul Vespa, MD; J. Pablo Villablanca, MD; Harry
Kelley, MD; and Donna Singleton, RN. State University of New Vinters, MD; and Fernando Vinuela, MD. Swedish (Denver) Med-
York at Buffalo (1): PI: L. Nelson Hopkins, MD; Lee Guterman, ical Center (9): Co-PIs: Don Frei, MD, and Dan Huddle, MD;
MD; Elad Levy, MD; Jay Howington, MD; Mark Harrigan, MD; Richard Bellon, MD; Christopher Finale, MD; Carol Greenwald,
Ricardo Hanel, MD; and Annemarie Crumlish. University of North MD; and Don Smith, MD. Florida Hospital Neuroscience Institute
Carolina–Chapel Hill (1): PI: Sten Solander, MD; Ana Felix, MD; (8): PI: Frank Hellinger, MD; Laura Billanovic, RN; and Susan
Souvik Sen, MD; David Huang, MD; Nydia Melendez, MD; and Mitchell, RN. NY Presbyterian Hospital–Cornell (4): PI: Alan Segal,
Susan Wilson, MSN, FNP. Washoe Medical Center (1): PI: Paul MD; Y. Pierre Gobin, MD; Jeffrey Katz, MD; Igor Ougrets, MD;
Katz, MD; Bradley Glenn, MD; Timothy Koci, MD; Anthony Bruno, Howard Riina, MD; and Kimberly Salvaggio, NP. University of
Calgary, Foothills Hospital (4): PI: Michael Hill, MD; Philip Barker,
MD; Mark Algood, MD; and Marta Heffner, RN. Baptist Memorial
MD; Andrew Demchuk, MD; Imanuel Dzialowski; Karyn Fischer,
Clinical Research Center: PI: John Barr, MD; Paul Broadbent, MD;
RN, MD; William Hu; Mark Hudon, MD; Will Morrish, MD; Suresh
Soren A. Singer, MD; Stephen D. Morris, MD; Sanat Dixit, MD; and
Subramanian, MD; Tim Watson, MD; and John Wong, MD. NY
Grace Miller. Barrow Neurological Institute: PI: James Frey, MD; Presbyterian Hospital–Columbia (3): PI: John Pile-Spellman, MD;
Cameron McDougall, MD; Felipe Albuquerque, MD; Mark Hekler, Sean Lavine, MD; Philip Meyers, MD; and Leslie Schmidt, NP.
MD; David Fiorella, MD; Seth Larson, MD; Shafeeq Ladha, MD; Georgetown University (3): PI: Vance Watson, MD; John DeSi-
Darin Okuda, MD; and Mary Harrigan, RN, MN. Baton Rouge mone, MD; Timea Hodics, MD; Theresa Kowal, RN; Farid Parham,
General Hospital: PI: Albert Alexander, MD; Joseph Acosta, MD; MD; Susan Sutten, MPH; and Manual Yepes, MD. Stanford Uni-
Jon Olson, MD; Kevin Callerame, MD; Rodney Hillis, MD; and versity Medical Center (2): PI: Michael Marks, MD; Gregory Albers,
Kimberly Hendricks, RN, MN. Emory University: PI: Frank Tong, MD; James Castle, MD; Huy Do, MD; Mahesh Jayerman, MD;
MD; Jacques Dion, MD; Michael Frankel, MD; Barney Stern, MD; Marten Lansberg, MD; Mary Marcellus, RN; Chitra Venkatsubma-
Owen Samuels, MD; and Marc Chimowitz, MD. University of ran, MD; and Christine Wijman, MD. University of Alberta, Edm-
Texas, Houston: PI: Morgan Campbell, MD; John Choi, MD; Frank onton (2): PI: Ashfaq Shuaib, MD; Robert Ashforth, MD; Derek
Yatsu, MD; Marc Malkoff, MD; James Grotta, MD; Edwin Cacay- Emery, MD; Faraz Al-Hussain, MD; Muhammad Hussain, MD;
orin, MD; Christina Hall, MD; Lise Labiche, MD; Elizabeth Noser, Thomas Jeerakathil, MD; Kurshid Khan, MD; Mikael Murtaoghu,
MD; Joon Song, MD; Ken Uchino, MD; and Doralene Smith. MD; Nazir Rizvi, MD; Maher Saqqur, MD; James Scozzafava, MD;960 Stroke May 2010
Brenda Scwindt, RN; Muzaffar Siddiqui, MD; and Khalida Tariq, intra-arterial thrombolysis in middle cerebral artery and internal carotid
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Paul Broadbent, MD; Sanat Dixit, MD; Grace Miller; and Stephen D. 12. Mattle HP, Arnold M, Georgiadis D, Baumann C, Nedeltchev K, Ben-
Morris, MD. University of Pittsburgh Medical Center: PI: Tudor ninger D, Remonda L, von Büdingen C, Diana A, Pangalu A, Schroth G,
Jovin, MD; Max Hammer, MD; Michael Horowitz, MD; Vivek Baumgartner RW. Comparison of intraarterial and intravenous
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G.R.D. is a Scientific Advisor and stockholder in Concentric Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial, part
Medical, Inc. G.W. is an employee of Concentric Medical, Inc. I. AJNR Am J Neuroradiol. 2006;27:1177–1182.
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Division Occlusions After Mechanical Thrombectomy: Pooled Analysis of the Mechanical
Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI Trials
Zhong-Song Shi, Yince Loh, Gary Walker and Gary R. Duckwiler
for the MERCI and Multi-MERCI Investigators
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Stroke. 2010;41:953-960; originally published online April 8, 2010;
doi: 10.1161/STROKEAHA.109.571943
Stroke is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 2010 American Heart Association, Inc. All rights reserved.
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An erratum has been published regarding this article. Please see the attached page for:
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The article, “Clinical Outcomes in Middle Cerebral Artery Trunk Occlusions Versus Secondary
Division Occlusions After Mechanical Thrombectomy: Pooled Analysis of the Mechanical
Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI Trials” by Shi et al (Stroke.
2010;41:953–960) included an error in Appendix 2. Dr Fawaz Al-hussain’s name and affiliation
were incorrect. The correct information appears below as well as in the current online version.
The investigator’s name should appear as Fawaz Al-hussain, MD, King Saud University.
(Stroke. 2012;43:e110.)
© 2012 American Heart Association, Inc.
Stroke is available at http://stroke.ahajournals.org DOI: 10.1161/STR.0b013e318273dc51
e110Stroke May 2010
Original Contributions
大脑中动脉主干闭塞与第二段闭塞机械取栓术的临床结局 ：
脑缺血机械取栓 (MERCI) 和多中心 MERCI 试验的汇总分析
Clinical Outcomes in Middle Cerebral Artery Trunk Occlusions Versus Secondary
Division Occlusions After Mechanical Thrombectomy:
Pooled Analysis of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI)
and Multi MERCI Trials
Zhong-Song Shi, MD; Yince Loh, MD; Gary Walker, PhD; Gary R. Duckwiler, MD; for the MERCI
and Multi-MERCI Investigators
背景和目的：血管内血管再通术对急性缺血性卒中患者有益，但其益处是否在大脑中动脉(MCA)第二段(M2)
闭塞与MCA主干(M1)闭塞存在差异尚不清楚。本文对由血管造影术确定的MCA M1闭塞患者与单独M2闭塞患
者，用Merci Retriever装置进行机械取栓后的血管再通状态和临床结局进行了比较。
方法：回顾性分析了脑缺血机械取栓(MERCI)和多中心MERCI试验中MCA卒中患者的汇总数据。患者分成两
组：MCA M1闭塞和单独M2闭塞，评价了两组的基线特征、血管再通率、出血率、并发症、结局和死亡率。
结果：MERCI和多中心MERCI试验中的178例MCA闭塞患者，84.3%为M1闭塞，15.7%为单独M2闭塞。单独
M2闭塞患者与M1闭塞患者相比有更高的血管再通率，更少的平均机械疏通次数，且具有更短平均操作时间
的趋势。尽管在所有患者中，M2的结局从数字上看是优于M1，但M2与M1组之间在症状性出血、有临床意义
的操作不良反应、90天良好结局或90天的死亡率等方面无统计学差异。在多因素分析中，最终的血管再通是
90天良好结局最强的预测因素。
结论：MCA M1闭塞和单独M2闭塞的患者在接受机械取栓后可以达到相对高的血管再通率和良好的临床结
局。而事实上，与M1闭塞的患者相比，单独M2闭塞患者具有更高的血管再通率，需要更少的机械疏通次数
且没有增加并发症。
关键词：急性脑卒中 血管内治疗 大脑中动脉 结局 取栓术
(Stroke.2010;41;953-960. 林森 译 曾进胜 校)
颅内大动脉闭塞引起的急性缺血性卒中患者对 闭塞的血管再通状态优于 MCA M1 闭塞 [9,10]。 具有
溶栓治疗的反应不尽相同，可能取决于动脉闭塞的 良好临床结局的 MCA M2 闭塞患者约两倍于 MCA
位置不同。在美国神经疾病与卒中研究所、欧洲急 M1 闭塞患者 [9]。
性卒中协作研究 (ECASS) 以及阿替普酶静脉注射 急性脑血栓栓塞溶栓试验Ⅱ (PROACT II) 研究
(IV) 非介入治疗急性缺血性卒中的临床试验中，使 纳入的 MCA M1 闭塞患者占患者总数的 61.7%，其
用组织型纤溶酶原激活剂 (tPA) 静脉溶栓，由于缺乏 余 大 多 是 单 独 MCA M2 闭 塞 ；然 而， 根 据 M1 与
对血栓的准确定位，动脉闭塞类型既不影响血管再 M2 闭塞分层比较临床结局的研究罕有报告 [5]。 最近
通状态也不影响临床结局 [1–4]。大脑中动脉 (MCA) 的尿激酶 IA 溶栓治疗的研究显示 MCA M1 闭塞的
供血区的卒中在缺血性卒中的所占比例最大。然而， 血管再通状态要优于单独 M2 闭塞，但却没有描述
IV 和动脉内 (IA) 溶栓治疗则很少报道血管再通状态 不同闭塞部位与临床结局的关系 [11,12]。
和临床结局在 MCA 主干 (M1) 闭塞和单独第二段 (M2) 对于起病 8 小时内 IV tPA 治疗不适用或失败的
闭塞中的差别 [1–8]。最近应用经颅多普勒超声和 / 或 急性缺血性卒中患者，应用 Merci 器械进行机械取
CT 血管成像的研究发现在 IV tPA 治疗后，MCA M2 栓是一种很有前景的替代疗法 [13-17]。脑缺血机械取
From the Division of Interventional Neuroradiology (Z.S.S., Y.L., G.R.D.), David Geffen School of Medicine at UCLA, Los Angeles, Calif; and Concentric Medical, Inc (G.W.),
Mountain View, Calif.
Current affiliation for Z.S.S.: Department of Neurosurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, P.R.China.
Current affiliation for Y.L.: Neurovascular Service, Department of Medicine, Madigan Army Medical Center, Tacoma, Wash.
Correspondence to Gary R. Duckwiler, MD, Division of Interventional Neuroradiology, David Geffen School of Medicine at UCLA, 757 Westwood Plaza, Los Angeles, CA
90095-7437. E-mail gduckwiler@mednet.ucla.edu
© 2010 American Heart Association, Inc.
22Shi et al Outcomes in MCA Occlusions With the Merci Retriever
栓 (MERCI) 和多中心 MERCI 第一部分试验的汇总 NIHSS 降低≧ 4 分的操作并发症或死亡、需要外科
分析已经证明，颈内动脉闭塞的患者可以达到相对 手术或输血处理的腹股沟区并发症。
较高的血管再通率 [17]。 然而，它并没有评估 MCA 神经状态由 NIHSS 和 30 及 90 天的改良 Rankin
M2 闭 塞 与 MCA M1 闭 塞 的 机 械 性 血 管 再 通 的 结 评分 (mRS) 来评定。各闭塞组患者的评估内容包括血
局差异。本研究的目的是评价经过血管造影确定的 管再通率、出血转化率、临床上严重的操作相关并发
MCA M1 闭塞与单独 M2 闭塞的急性缺血性卒中患 症、90 天临床结局及死亡率。90 天良好的结局被定义
者使用 Merci Retriever 装置进行机械取栓术是否会 为 mRS ≤ 2。由于单独 M2 闭塞样本较小，M1 和 M2
影响其血管再通状态。同时本研究也旨在通过血管 闭塞的数据被汇总起来并进行多元 logistic 回归分析
再通状态比较不同组 (M1 vs. M2) 中所有 MCA 闭塞 以此来确定 90 天良好结局的独立预测变量。对血管
患者使用机械取栓术的安全性和有效性。 再通状态分层后进行临床特点、并发症和结局的比较。
组与组之间差异的比较采用 95% CI。如果这
方法 个区间不包含 0，组之间的差异在 P=0.05 时被认为
MERCI 与多中心 MERCI 试验的汇总数据对确 是有意义的。虽然这是一个回顾性的亚组分析，但
定的急性 MCA 卒中进行了回顾分析。汇总数据包 所考虑的两个组的样本大小应该是在两组间结局比
括总共 305 例缺血性卒中患者，其中 141 例来自于 较上至少具有 80% 的效能检出 28% 的绝对差异和
MERCI 试 验，164 例 来 自 于 多 中 心 MERCI 试 验。 50% 的效能检出 20% 的绝对差异。单因素分析确定
这两个试验的详细计划书在之前的研究中已经作了 90 天的良好结局的独立预测变量，其中所有 Wald
描述 [13-17]。简单来说，纳入试验的患者不是不适合 χ 2 PStroke May 2010
表1 不同闭塞位置患者的特征
总数 MCA M1 MCA M2
(n=178) (n=150) (n=28) P*
年龄中位数，年 (IQR) 73.0(60.0-80.0)(178) 73.0(60.0-80.0)(150) 71.5(61.5-81.0)(28) 0.94
女性 57.9%(103/178) 56.0%(84/150) 67.9%(19/28) 0.30
高血压 77.5%(138/178) 77.3%(116/150) 78.6%(22/28) >0.99
糖尿病 24.8%(44/177) 25.0%(37/149) 24.9%(7/28) 0.99
血脂异常 34.8%(57/164) 34.1%(47/138) 38.5%(10/26) 0.67
冠状动脉病 39.7%(69/174) 43.2%(63/146) 21.4%(6/28) 0.04
充血性心力衰竭 21.6%(38/176) 22.3%(33/148) 17.9%(5/28) 0.59
吸烟 18.4%(30/163) 19.6%(27/138) 12.0%(3/25) 0.35
房颤 44.1%(78/177) 41.6%(62/149) 57.1%(16/28) 0.15
血液系统疾病 6.3%(11/174) 6.2%(9/146) 7.1%(2/28) 0.85
周围血管疾病 12.1%(21/173) 13.1%(19/145) 7.1%(2/28) 0.35
血糖，mg/dL 134.2±51.4(176) 134.6±51.8(149) 132.1±49.9(27) 0.82
凝血酶原时间，秒 13.4±4.4(170) 13.1±3.2(143) 15.1±8.1 (27) 0.03
活化部分凝血激酶时间，秒 30.1±17.8(160) 30.2±19.1(134) 29.3±8.6(26) 0.8
国际标准化比值 1.21±0.49(174) 1.18±0.42(148) 1.34±0.8(26) 0.13
血小板 ( 计数 ) 240.4±77.2(175) 238.4±77.5(148) 251.4±75.4(27) 0.42
收缩压中位数，mmHg(IQR) 150.0(131-165)(176) 147.0(130-163)(149) 157.0(132-176)(27) 0.08
舒张压中位数，mmHg(IQR) 75.5(64-85)(176) 74.0(62-84)(149) 80.0(68-91)(27) 0.09
基线 NIHSS，中位数 (IQR) 18.0(14-23)(178) 18.0(15-23)(150) 17.0(14-22)(28) 0.56
左侧 MCA 闭塞 50.6%(90/178) 47.3%(71/150) 67.9%(19/28) 0.06
起病至腹股沟穿刺时间中位数，小时 (IQR) 4.3(3.2-5.4)(177) 4.3(3.2-5.5)(149) 4.7(3.7-5.3)(28) 0.35
Merci 前静脉 tPA 失败 15.2%(27/178) 14.0%(21/150) 21.4%(6/28) 0.33
动脉溶栓治疗 32.0%(57/178) 30.7%(46/150) 39.3%(11/28) 0.38
静脉或动脉溶栓治疗 41.6%(74/178) 40.0%(60/150) 50.0%(14/28) 0.33
静脉和动脉溶栓治疗 5.6%(10/178) 4.7%(7/150) 10.7%(3/28) 0.19
白种人 84.8%(151/178) 82.7%(121/150) 96.4%(27/28) 0.05
*P 值 ：连续变量采用两样本 Wilcoxon 检验，分类变量采用 Fisher 精确检验计算。
IQR ：四分位数间距。
有统计学差异。MCA M1 闭塞患者可能更易患冠状 M1 闭塞组相比，从数字上看具有较高的比例 (40.7%
动脉病，且凝血酶原时间更短，收缩压更低 ( 表 1)。 vs. 33.3%)，但两组 90 天良好临床结局 (mRS ≦ 2) 并
在 M1 组中，最常使用 X6 和 L5 装置 ( 均为 44.7%)， 无统计学差异 ( 表 2)。一般来说，远端动脉闭塞预
X5(34.0%) 和 X4(6.7%) 的使用则较少。在 M2 组中， 期有更好的结局，但在本系列中，左侧 M2 闭塞占
最常用的是 L5 装置 (53.6%)，紧接着是 X6(28.6%)， 67.9% 而左侧的 M1 闭塞只有 47.3%( 有认为左侧大脑
之后是 X5(25.0%)，未使用 X4。两组中，7% 的患 半球梗死患者长期预后差， 而本组M2闭塞左侧更多)。
者在评定其基线 NIHSS 分数时应用了镇静剂。尽管 两组 90 天的死亡率也无统计学差异，然而，从
与 M1 组 (52.5%) 相比，M2 组 (73.1%) 患者存在明 数字上看，单独 MCA M2 闭塞组比 MCA M1 闭塞
显更高比例的严重或完全性失语，但两组中 NIHSS 组低 (25.9% vs. 32.9% ；表 2)。
的运动评分部分无统计学差异。
出血并发症
血管再通率 两组颅内出血率无统计学差异 (M1 组 36.7% vs.
经 Merci 治疗后的即时血管再通率 (TIMI II/III M2 组 42.9%)。同样，两组的症状性出血率也无统
血 流 分 级 ) 在 MCA M1 组 与 单 独 M2 组 中 分 别 为 计学差异 (M2 组 3.6% vs. M1 组 6.7%)。从数字上看，
46.0% 和 71.4%( 表 2)。包括接受联合治疗的患者在 M2 闭塞患者的有临床上严重操作相关不良反应比
内，单独 MCA M2 组的最终血管再通率高于 MCA M1 闭塞更低 (3.6% vs. 5.3%)。
M1 组 (82.1% vs. 60.0%)。 相对于 MCA M1 闭塞，
另外，
单独 MCA M2 闭塞所需的疏通次数更少 (2.1 vs. 3.1) 多元Logistic回归分析
并具有平均操作时间更短的趋势 (1.6 vs. 1.8 小时 )。 与先前的 MERCI 试验分析相似，年龄、基线
NIHSS 和操作后的血管再通状态均为 90 天良好临床
良好结局和死亡率 结局的预测因素。具体结果见表 3。最终的血管再通
尽管单独 MCA M2 闭塞组的良好结局与 MCA 状态是良好结局最强的独立预测因素 (OR 为 30.91)。
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