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Ischemic stroke
Original research
Endovascular treatment for M2 occlusions in the era of stentrievers: a descriptive multicenter experience
  1. Alan Flores1,
  2. Alejandro Tomasello2,
  3. Pere Cardona3,
  4. M Angeles de Miquel3,
  5. Meritxell Gomis4,
  6. Pablo Garcia Bermejo4,
  7. Victor Obach5,
  8. Xabi Urra5,
  9. Joan Martí-Fàbregas6,
  10. David Cánovas7,
  11. Jaume Roquer8,
  12. Sònia Abilleira9,
  13. Marc Ribó1,
  14. on behalf of the Catalan Stroke Code and Reperfusion Consortium (Cat-SCR)
  1. 1Stroke Unit, Department of Neurology, Hospital Vall d'Hebron, Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
  2. 2Department of Radiology, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
  3. 3Department of Neurology, Hospital Universitari de Bellvitge, Barcelona, Spain
  4. 4Department of Neurology, Hospital Universitari Germans Trias I Pujo, Badalona, Spain
  5. 5Department of Neurology, Hospital Clínic I Provincial, Barcelona, Spain
  6. 6Department of Neurology, Hospital Santa Creu i Sant Pau, Barcelona, Spain
  7. 7Department of Neurology, Consorci Sanitari Parc Taulí, Barcelona, Spain
  8. 8Department of Neurology, Hospital del Mar, Barcelona, Spain
  9. 9Stroke Programme, Catalan Agency for Health Information, Assessment, and Quality, Barcelona, Spain
  1. Correspondence to Dr Alan Flores, Unitat d'Ictus, Hospital Vall d'Hebron, Passeig Vall d'Hebron 119-129, Barcelona 08035, Spain; alanflo2507{at}hotmail.com

Abstract

Background Patients with M2 middle cerebral artery (MCA) occlusions are not always considered for endovascular treatment.

Objective To study outcomes in patients with M2 occlusion treated with endovascular procedures in the era of stentrievers.

Methods We studied patients prospectively included in the SONIIA registry (years 2011–2012)—a mandatory, externally audited registry that monitors the quality of reperfusion therapies in Catalonia in routine practice. Good recanalization was defined as postprocedure Thrombolysis in Cerebral Infarction (TICI) score 2b–3; dramatic recovery as drop in National Institutes of Health Stroke Scale (NIHSS) score >10 points or NIHSS score <2 at 24–36 h; and good outcome as modified Rankin score (mRS) 0–2 at 3 months. A 24 h CT scan determined symptomatic intracranial hemorrhage (SICH) and infarct volume.

Results Of 571 patients who received endovascular treatment, 65 (11.4%) presented an M2 occlusion on initial angiogram, preprocedure NIHSS 16 (IQR 6). Mean time from symptom onset to groin puncture was 289±195 min. According to interventionalist preferences 86.2% (n=56) were treated with stentrievers (n=7 in combination with intra-arterial tissue plasminogen activator (tPA), 4.6% (n=3) received intra-arterial tPA only, and 9.2% (n=6) diagnostic angiography only. Good recanalization (78.5%) was associated with dramatic improvement (48% vs 14.8%; p=0.02), smaller infarct volumes (8 vs 82 cc; p=0.01) and better outcome (mRS 0–2: 66.3% vs 30%; p=0.03). SICH (9%) was not associated with treatment modality or device used. After adjusting for age and preprocedure NIHSS, good recanalization emerged as an independent predictor of dramatic improvement (OR=5.9 (95% CI 1.2 to 29.2), p=0.03). Independent predictors of good outcome at 3 months were age ( OR=1.067 (95% CI 1.005 to 1132), p=0.03) and baseline NIHSS ( OR=1.162 (95% CI 1.041 to 1.297), p<0.01).

Conclusions Endovascular treatment of M2 MCA occlusion with stentrievers seems safe. Induced recanalization may double the chances of achieving a favorable outcome, especially for patients with moderate or severe deficit.

  • Stroke
  • Thrombectomy
  • Angiography

https://doi.org/10.1136/neurintsurg-2014-011100

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    Background

    Despite their ability to achieve high rates of recanalization in acute ischemic stroke, endovascular procedures with last-generation devices such as stentrievers are under investigation in multiple randomized trials to demonstrate their benefits.1–3 The still uncertain benefits of endovascular procedures in proximal intracranial vessel occlusions are even more controversial when considering distal occlusions such as the M2 middle cerebral artery (MCA) segment. In M2 occlusions clinical outcome might be independent of recanalization given the limited amount of tissue at risk; however, strategic small infarct may also cause significant clinical and functional impairment.4

    The limited number of studies focusing on patients with M2 MCA occlusion show contradictory results. On the one hand, an Interventional Management of Stroke II (IMS II) study subanalysis of patients with an M2 occlusion on initial angiogram showed a low rate of recanalization (Thrombolysis in Myocardial Infarction (TIMI) score 2–3: 43%) but high rate of good clinical outcome (90 days modified Rankin score (mRS) 0–2: 65%).4 On the other hand, data from the Multi- Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trials in a similar population showed a high rate of recanalization (TIMI 2–3: 81%) but a low rate of favorable outcome (mRS 0–2: 40.7%).2 Finally, a subgroup analysis of the PROACT-II study showed the benefits of recanalization that could double the chance of a good clinical outcome at 90 days.5 In all these studies patients were treated with procedures or devices that are surpassed by the results of new-generation stentrievers.6 ,7

    We aimed to investigate the possible benefits and safety of endovascular procedures in the era of stentrievers in patients with acute stroke with an M2 MCA occlusion treated under routine clinical conditions and included in a multicentric official registry of patients.

    Methods

    We studied patients prospectively included in the Sistema ONline d'Informació de l'Ictus Agut (SONIIA) registry from January 2011 to December 2012, a mandatory and externally audited registry that monitors quality of all reperfusion therapies performed in Catalonia under routine practice conditions.8 Stentrievers were widely used in routine practice before the registry was set up and all interventionalists had considerable experience in the use of the devices.

    Baseline characteristics, including preprocedure National Institutes of Health Stroke Scale (NIHSS) score and occlusion location on initial angiogram, were collected for all patients. Only patients with an initial occlusion in the M2 segment of the MCA were included. The decision to perform endovascular procedures was made according to the stroke neurologist and interventionalist criteria.

    We defined good recanalization as Thrombolysis in Cerebral Infarction (TICI) score 2b–3 on the last angiogram, and dramatic recovery as an NIHSS score drop ≥10 points or NIHSS <2 at 24–36 h. Favorable clinical outcome was considered when mRS at 3 months was 0–2. We determined the presence of hemorrhagic transformation9 on the 24–36 h CT scan. This scan was also used to calculate infarct volume10 in all patients treated in one of the centers. The registry also requires prospective recording of all procedural related complications.

    Statistical analysis

    Descriptive and frequency statistical analyses were obtained using SPSS 17.0 software. Categorical variables are presented as absolute values and percentages, and continuous variables as median±SD if normally distributed or median (interquartile intervals) if not normally distributed. Statistical significance for intergroup differences was assessed by Pearson χ2 or Fisher exact test for categorical variables and by Student t or Mann–Whitney U test for continuous variables.

    Multivariable logistic regression analyses were performed for each group to determine factors that could be considered as independent predictors of favorable outcome.

    Variables showing p<0.1 in univariate analysis were included in the multivariate model. A probability value of <0.05 was considered significant for all tests.

    Results

    Of the 571 registered patients who received endovascular treatment in the study period, 65 (11.4%) presented a single M2 occlusion on the initial angiogram. They had the following characteristics: mean age 66±15 years, female 47.7%, median preprocedure NIHSS 16 (IQR 6), and 45 cases (69.2%) were left MCA M2 occlusions. Thirty-five patients (53.8%) received intravenous (IV) tissue plasminogen activator (tPA) before the procedure. Ten patients (15.4%) received general anesthesia before the procedure. Mean time from symptom onset to groin puncture was 289±195 min. Baseline characteristics are shown in table 1.

    View this table:
    Table 1

    Baseline characteristics of patients and main outcomes according to early recanalization or not

    According to interventionalist preferences, of the 65 patients, 86.2%, (n=56) were treated with stentrievers; of these 10.8% (n=7) in combination with intra-arterial (IA) tPA, 4.6% (n=3) received IA tPA only (n=3), and the rest 9.2% (n=6) received diagnostic angiography only. The following stentrievers were used, Solitaire FR Covidien, Mindframe Capture, Trevo Pro Retrieval System by Concentric Medical, Preset stent retriever. Detailed information on the specific device or devices used in each case was not recorded.

    To obtain a better profile of the stentrievers we could have performed the analysis after excluding the few patients in whom a stentriever was not finally used (13.8%). However, to obtain a better report of the expected results in routine clinical practice, we decided to include all patients with an M2 MCA occlusion treated during the studied period. Of the six patients who received diagnostic angiography only (preprocedure NIHSS 11.5 (IQR 6)), four (67%) had a favorable clinical outcome at 3 months.

    Patients who achieved good recanalization (TICI score 2b–3: 78.5%, n=46) had more often dramatic improvement (48% vs 14.8%, p=0.02), smaller infarct volumes (8 vs 82 cc, p=0.01) and better outcome (mRS 0–2: 66.3% vs 30%; p=0.03) than those who did not recanalize (table 1). After adjusting for age and baseline NIHSS, good recanalization emerged as an independent predictor of dramatic improvement (OR=5.9 (95% CI 1.2 to 29.2), p=0.03). Previous IV tPA treatment was not associated with higher recanalization rates (28% vs 22% p=0.69).

    At 3 months 60% of patients had a good outcome and the death rate was 16.4%. Age, no history of hypertension, preprocedure NIHSS, and good recanalization were associated with good outcome. Independent baseline predictors of good outcome at 3 months were age (OR=1.067 (95% CI 1.005 to 1132), p=0.03) and preprocedure NIHSS (OR=1.162 (95% CI 1.041 to 1.297), p<0.01).

    The benefits of recanalization were more obvious in patients with initial NIHSS >8. All patients with initial NIHSS ≤8 had good clinical outcome independently of recanalization status. In patients with NIHSS >8 recanalization increased the chances of good outcome from 22.2% to 58.3% (p=0.05) (figure 1).

    Figure 1
    Figure 1

    Bars show rate of patients with good clinical outcome (modified Rankin score (mRS) ≤2) at 3 months according to preprocedure National Institutes of Health Stroke Scale (NIHSS).

    Symptomatic intracranial hemorrhage (SICH) occurred in six patients (9%), of whom three achieved recanalization and three did not (p=0.53) and two of them had been treated with IV tPA. The use of a stentriever in an M2 branch did not increase the rate of SICH (a stentriever was used in five of the six cases; p=0.169). One patient presented an arterial dissection during the procedure and one patient experienced a local hematoma at the puncture site.

    Nine patients died (13.8%) On univariate analysis, preprocedure NIHSS was associated with mortality (NIHSS 19.8 vs 13.3 p<0.01). None of the deaths was related to SICH.

    Discussion

    Our study describes for the first time outcomes of patients with acute stroke who had an M2 MCA occlusion treated with endovascular procedures in routine practice in the era of stentrievers. The study shows that achieving induced recanalization led to better outcomes without significantly increasing the rate of complications.

    In acute stroke management, identification of an occlusion in the M2 segment of the MCA may provide the treating physician with the dilemma of whether or not to start endovascular treatment. Physicians might consider that the limited endangered area does not justify the risks and costs of the procedure. However, on the other hand, a small but strategic cerebral infarct may lead to significant permanent neurological impairment.

    The prognosis and best management of acute distal intracranial arterial occlusions, including M2 MCA, is not clear. A recent study describing the natural history of patients with stroke who did not receive any reperfusion treatment showed that up to 44% of patients presenting with a distal MCA occlusion did not achieve a good outcome at 3 months.11 A substudy of the IMS II trial,4 in which patients were treated with IA tPA + endovascular ultrasound with the EKOS catheter, showed that although only 10/23 (43.5%) M2 occlusions achieved grade 3 arterial occlusive lesion recanalization, up to 16/23 (69.6%) achieved mRS 0–2 outcome. A recently published subanalysis of the PROACT trial,5 showed that in patients with documented M2 occlusion, IA treatment with urokinase tripled the rate of recanalization (53% vs 16%) and doubled the chance of a favorable functional outcome (53% vs 28%) as compared with best medical treatment. Another study suggested a greater reduction of infarct volume with IA therapies before stentrievers were widely available as compared with either IV tPA or no reperfusion treatment.12 In that study, the magnitude of infarct volume reduction was maximal in proximal occlusions but still significant for M2 MCA occlusions. The authors found that independently of occlusion site, a baseline NIHSS cut-off point of ≥14 points identified best responders to IA therapies. Our work that specifically studied patients with an M2 occlusion treated with improved devices such as stentrievers showed that patients with a baseline NIHSS>8 benefited most from recanalization.

    Our study was intended to help clinicians in the decision-making process of indicating an endovascular procedure in patients with M2 MCA occlusion in a routine clinical practice setting in which devices with improved features6 ,7 such as stentrievers are available. While all patients with an initial NIHSS≤8 achieved a good outcome independently of final recanalization, in patients with NIHSS >8 the outcome was markedly influenced by the achievement of recanalization (mRS 0–2: 58% vs 22%). This fact combined with the high observed rate of recanalizaton and the low rate of complications, as compared with previous studies that showed death rates >20%,2 ,5 advocates the use of stentrievers in confirmed M2 MCA occlusions, especially if causing moderate to severe symptoms.

    Our study has several limitations for a descriptive study. First, the small sample; second, although the majority of the devices were stentrievers, there were other treatments, such as IA tPA; and finally, it did not include a control group receiving no intervention that could confirm our findings. However, this is a consecutive, prospective and externally audited series that shows for the first time trends in safety and improved outcome in patients with distal MCA occlusions treated under routine clinical conditions in the era of stentrievers. Most patients were treated in high-volume centers with interventionalists with extensive experience with stentrievers. This should be taken into account when applying the conclusions of our study to other situations.

    Conclusion

    Endovascular treatment of M2 MCA occlusion with stentrievers seems safe. Induced recanalization may double the chances of achieving a favorable outcome, especially in patients with moderate to severe symptoms.

    References

    1. ↵
      1. Broderick JP,
      2. Palesch YY,
      3. Demchuk AM,
      4. et al
      . Endovascular therapy after intravenous t-PA versus t-PA alone for stroke. N Engl J Med 2013;368:893–903.
      OpenUrlCrossRefPubMedWeb of Science
    2. ↵
      1. Shi ZS,
      2. Loh Y,
      3. Walker G,
      4. et al
      .; MERCI and Multi-MERCI Investigators. 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. Stroke 2010;41:953–60.
      OpenUrlAbstract/FREE Full Text
    3. ↵
      Penumbra Pivotal Stroke Trial Investigators. 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 2009;40:2761–8.
      OpenUrlAbstract/FREE Full Text
    4. ↵
      1. Tomsick T,
      2. Broderick J,
      3. Carrozella J,
      4. et al
      . Interventional Management of Stroke II Investigators. Revascularization results in the Interventional Management of Stroke II trial. AJNR 2008;29:582–7.
      OpenUrlAbstract/FREE Full Text
    5. ↵
      1. Rahme R,
      2. Abruzzo TA,
      3. Martin RH
      et al. Is intra-arterial thrombolysis beneficial for M2 occlusions? Subgroup analysis of the PROACT-II trial. Stroke 2013; 44:240–2.
      OpenUrlAbstract/FREE Full Text
    6. ↵
      1. Saver JL,
      2. Jahan R,
      3. Levy EI,
      4. et al
      . Solitaire flow restoration device versus the Merci retriever in patients with acute ischaemic stroke (SWIFT): a randomised, parallel-group, non-inferiority trial. Lancet 2012;380:1241–9.
      OpenUrlCrossRefPubMedWeb of Science
    7. ↵
      1. Nogueira RG,
      2. Lutsep HL,
      3. Gupta R,
      4. et al
      . Trevo versus Merci retrievers for thrombectomy revascularisation of large vessel occlusions in acute ischaemic stroke (TREVO 2): a randomised trial. Lancet 2012;380:1231–40.
      OpenUrlCrossRefPubMedWeb of Science
    8. ↵
      1. Abilleira S,
      2. Dávalos A,
      3. Chamorro A,
      4. et al
      . Catalan Stroke Code and Thrombolysis Study Group. Outcomes of intravenous thrombolysis after dissemination of the stroke code and designation of new referral hospitals in Catalonia: the Catalan Stroke Code and Thrombolysis (Cat-SCT) Monitored Study. Stroke 2011;42:2001–6.
      OpenUrlAbstract/FREE Full Text
    9. ↵
      1. Hacke W,
      2. Kaste M,
      3. Bluhmki E
      et al. Thrombolysis with alteplase 3 to 4.5 h after acute ischemic stroke. N Engl J Med 2008;359:1317–29.
      OpenUrlCrossRefPubMedWeb of Science
    10. ↵
      1. Van der Worp HB,
      2. Claus SP,
      3. Bar PR,
      4. et al
      . Reproducibility of measurements of cerebral infarct volume on CT scans. Stroke 2001;32:424–30.
      OpenUrlAbstract/FREE Full Text
    11. ↵
      1. Hernández-Pérez M,
      2. Pérez de la Ossa N,
      3. Aleu A,
      4. et al
      . Natural history of acute stroke due to occlusion of the middle cerebral artery and intracranial internal carotid artery. J Neuroimaging 19 Nov 2013. Epub ahead of print.
    12. ↵
      1. Rangaraju S,
      2. Owada K,
      3. Noorian AR,
      4. et al
      . Comparison of final infarct volumes in patients who received endovascular therapy or intravenous thrombolysis for acute intracranial large-vessel occlusions. JAMA Neurol 2013;70:831–6.
      OpenUrlCrossRefPubMedWeb of Science

    Footnotes

    • Contributors MR and AF participated in the conception and design of the study. MR, AF and SA analyzed and interpreted the data. MR, AT, PC, MG, PGB, VO, XU, JM-F, DC and JR treated and included the patients in the study. MR carried out the statistical analysis and wrote the article. All authors advised, reviewed and approved the manuscript.

    • Competing interests MR is the recipient of a grant from Instituto de Salud Carlos III, Ministerio de Economía y Competitividad (FIS: PS09/01660). AS is the recipient of a Rio Ortega grant from the Instituto de Salud Carlos III, Ministerio de Economía y Competitividad.

    • Patient consent Obtained.

    • Provenance and peer review Not commissioned; externally peer reviewed.