Purpose To evaluate the effectiveness and safety of rescue stenting (RS) after failed mechanical thrombectomy (MT) for patients with large artery occlusion in the anterior circulation.
Methods Consecutive patients who experienced failed reperfusion and subsequently did or did not undergo RS at 16 comprehensive stroke centers were enrolled from January 2015 to June 2018. Propensity score matching was used to achieve baseline balance between the patient groups. Symptomatic intracranial hemorrhage (sICH) at 48 hours and the modified Rankin Scale scores and mortality at 3 months in the two groups were compared.
Results A total of 90 patients with RS and 117 patients without RS after failed MT were enrolled. Propensity score matching analysis selected 132 matched patients. The good outcome rate was significantly higher in matched patients with RS than in those without RS (36.4% vs 19.7%, p=0.033), whereas the sICH (13.6% vs 21.2%, p=0.251) and mortality (31.9% vs 43.9%, p=0.151) were not significantly different between the groups.
Conclusions RS seems to be an effective safe choice for patients with large vessel occlusion of the anterior circulation who underwent failed MT.
- rescue stenting
- mechanical thrombectomy
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Mechanical thrombectomy (MT) using a stent retriever device is the first-line approach for patients with acute ischemic stroke caused by proximal artery occlusion in the anterior circulation.1 Randomized controlled trials, however, have reported that, even in patients who undergo MT, 12.0–41.3% still had failed reperfusion.2–6 Subsequently, rescue therapy (eg, intra-arterial thrombolysis, balloon angioplasty or stenting) is used to further improve reperfusion and outcome.7–9 In recent years, evaluating the efficacy and safety of rescue stenting (RS) in patients with proximal vessel occlusion in the anterior circulation has attracted much interest. Previous studies indicate that RS is significantly associated with successful reperfusion and good outcomes without increasing the risk of symptomatic intracranial hemorrhage (sICH) or mortality.10–13 Nevertheless, further investigation is needed to confirm any conclusions reached on this subject because of the relatively small numbers of patients who have been treated with RS.
The aim of this study was to compare the efficacy and safety of using a propensity score matching analysis of patients who did and did not undergo RS after failed MT for acute large vessel occlusion in the anterior circulation.
We retrospectively enrolled consecutive patients with large vessel occlusion in the anterior circulation who did or did not undergo RS because reperfusion had failed after procedures (eg, MT, intra-arterial thrombolysis or tirofiban, balloon angioplasty, or any combination thereof) at 16 comprehensive stroke centers from January 2015 to June 2018. Patients were included in this study if they (1) were aged ≥18 years; (2) were within the 12-hour interval between symptom onset and puncture; (3) had occlusion of the intracranial internal carotid artery or M1 segment of the middle cerebral artery confirmed by CT angiography, magnetic resonance angiography, or digital subtraction angiography; and (4) had a modified Rankin Scale (mRS) score before stroke of <2.
This retrospective study was approved by the ethics committee of the involved centers. The need for informed consent was waived owing to the retrospective design.
Detailed clinical information was retrieved from each center, including demographic data, clinical characteristics, vascular risk factors, medical history, procedure-associated characteristics, and laboratory and neuroimaging data. All clinical and imaging data were sent to the Xinqiao Hospital. Two experienced physicians (FL and WZ) blindly assessed all the data. When there was disagreement, a third physician (FP) was asked to provide a final decision.
The severity of stroke was evaluated using the National Institutes of Health Stroke Scale (NIHSS) score at admission. A repeat CT scan was usually performed 48 hours following the procedure or whenever neurological deterioration occurred. sICH was defined according to the criteria of the Heidelberg Bleed Classification14: any hemorrhage at 48 hours after intervention combined with an increase in the total NIHSS score of ≥4 points or an increase of ≥2 points in one NIHSS category. The American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology was used to estimate the grade of collateral flow.15 We defined ‘procedure time’ as the interval from groin puncture to successful reperfusion or completion of the operation. The follow-up mRS score at 3 months was obtained by telephone or outpatient visit. Functional outcome at 3 months after the procedure was dichotomized into a good outcome (mRS 0–2) or a poor outcome (mRS 3–6).
At each center, the MT was conducted using general anesthesia or conscious sedation. A stent retriever device (Solitaire, Covidien, Irvine, California, USA or Trevo ProView, Stryker, Fremont, California, USA) was first used during MT. Successful reperfusion was defined as a score of 2b or 3 on the modified Treatment in Cerebral Ischemia Scale.16 If reperfusion of the targeting vessel failed despite multiple attempts, rescue treatment was performed at the discretion of experienced neurointerventionists. Such treatment included intra-arterial thrombolysis (with alteplase or urokinase), intra-catheter tirofiban, balloon angioplasty, stent placement, or any combination thereof. Antiplatelet protocol after procedures depended on the operator’s experience.
Continuous variables were compared using the Student’s t-test or the Mann–Whitney U test. Categorical variables were analyzed using the χ2 test. A propensity score-matched analysis was used to compare patients who underwent RS with those who did not. Matching (1:1) was performed according to the nearest-neighbor matching algorithm with a caliper of 0.2. The matched covariates included age, sex, baseline Alberta Stroke Program Early CT Score (ASPECTS), initial NIHSS score, and use of balloon angioplasty and intra-arterial tirofiban. Statistical analysis was conducted using R 3.1.3 and SPSS 23 software. Values of p<0.05 were considered to indicate statistical significance.
In all, 207 patients met the inclusion criteria during the study period. Following the failed interventions, 90 patients underwent RS and 117 did not. The baseline characteristics and clinical outcome of included patients are summarized in supplementary table S1 (online). The median initial NIHSS score was 17 (12.0–21.0). Altogether, 79 (87.8%) patients treated with RS experienced successful reperfusion. Compared with patients who did not undergo RS, the group who did had the following characteristics: higher rate of male patients (p=0.022); lower initial NIHSS scores (p=0.011); higher proportion of balloon angioplasties (p=0.036); increased baseline ASPECTS (p=0.012); and higher frequency of intra-arterial tirofiban treatment (p<0.001). There was a greater likelihood of a good outcome (p<0.001), successful reperfusion (p<0.001), and lower risk of mortality (p=0.016) in patients who underwent RS. sICH showed no difference between patients with and without RS (p=0.063).
Supplementary file 1
After propensity score matching, 66 patients with RS and 66 without RS were further compared. The results of these matched patients are shown in table 1. Baseline characteristics between the matched patients achieved good balance. Patients with RS had a significantly greater chance of a favorable outcome at 3 months after the procedure than those without RS (36.4% vs 19.7%, p=0.033), whereas sICH (13.6% vs 21.2%, p=0.251) and mortality (31.9% vs 43.9%, p=0.151) showed no statistical differences. The distribution of the mRS scores of the matched patients at 3 months is shown in figure 1.
This study showed that patients with proximal artery occlusion in the anterior circulation who underwent RS after failed MT experienced higher rates of successful reperfusion and good outcomes at 3 months than those who did not undergo RS. In addition, RS did not significantly increase the risk of sICH or mortality in these patients.
The advantage of RS after failed MT is improved recanalization. In contrast, the disadvantage of RS is that the intensive antiplatelet therapy after the procedure might increase the risk of sICH, especially in the setting of a large core infarction. Three recent cohort studies found that the successful reperfusion rate of RS following failed MT was 64.6–83.3%, the good outcome rate was 35.3–56.5%, the sICH rate was 4.3–16.7%, and the mortality rate was 4.3–23.5%. Thus, the results in patients who underwent RS after failed MT were superior to those for patients who did not undergo RS after MT failure.10–12 The proportions of favorable outcomes and sICH in patients in the present study who underwent RS were similar to those in previous studies,10–12 although there was a higher incidence of mortality. The median time from onset to puncture was longer in the present study, which may be an important reason for the higher mortality risk.
Several limitations should be considered when evaluating our findings. First, it has the inherent limitations of a retrospective observational study and selection bias. Second, patient selection for RS depended on the operator’s experience and lacked a uniform protocol. Third, the use of drugs, especially antiplatelet drugs, was based on the experience of the neurointerventionists. Fourth, the patients who were treated over a 6-hour time window were according to a favorable benefit–risk ratio and lacking perfusion imaging.
In conclusion, RS seems to be an effective safe choice for patients with large vessel occlusion of the anterior circulation who have experienced MT failure.
FP and JW contributed equally.
Contributors FP and JFW prepared the draft of the report. WHL, WGH, LW, TQ, SQY, QS, SZ, GYZ, YW, ABZ, YL, WH, CMW, ZHS ,and JP participated in data collection, data analysis, and interpretation. ZMQ, DPW, ZLG, and JS did the statistical analyses. QWY critically revised the report. WJZ and FLL did the study design. All authors participated in patient enrollment and reviewed the report and approved the final version.
Funding The project is supported by Army Military Medical University Clinical Medical Research Talents Training Program - Three Types of Plan (No. 2018XLC3039), Army Military Medical University Clinical Medical Research Talents Training Program (No. 2018XLC1005), Chongqing Major Disease Prevention and Control Technology Research Project (No. 2019ZX001), Army Military Medical University Clinical Medical Research Talents Training Program - Second Class Project, Question (No. 2018XLC2013).
Competing interests None declared.
Ethics approval Ethics committees of the involved centers.
Provenance and peer review Not commissioned; externally peer reviewed.