Futile recanalization after mechanical thrombectomy in patients with acute ischemic stroke and large ischemic core

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Korean J Cerebrovasc Surg. 2025;.jcen.2025.E2025.09.001

Publication date (electronic) : 2025 December 31

doi : https://doi.org/10.7461/jcen.2025.E2025.09.001

Yuichiro Tsuji^,1, Kohei Tsujino², Ryokichi Yagi¹, Ryo Hiramatsu¹, Yoshitaka Yamada³, Masahiko Wanibuchi¹

¹Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka, Japan

²Department of Neurosurgery, Shimizu Hospital, Kyoto, Japan

³Department of Neurosurgery, Nishinomiya Kyoritsu Neurosurgery Hospital, Nishinomiya, Hyogo, Japan

Correspondence to Yuichiro Tsuji Department of Neurosurgery, Osaka Medical and Pharmaceutical University, 2-7 Daigaku-machi Takatsuki-city, Osaka, Japan Tel +81726831221 Fax +81726813723 E-mail yuuichirou.tsuji@ompu.ac.jp

Received 2025 September 8; Revised 2025 December 8; Accepted 2025 December 8.

Abstract

INTRODUCTION

Multiple randomized controlled trials have shown that, compared to medical therapy, mechanical thrombectomy (MT) for acute ischemic stroke with a large ischemic core due to large-vessel occlusion (LVO) improves functional prognosis [2,4,13,16,24,25]. However, the rate of favorable outcomes remains low at only 20-30%.

In addition, despite successful recanalization, approximately half of patients do not achieve a favorable prognosis, a condition referred to as “futile recanalization” (FR) [20]. Several studies have examined FR and reported associated factors [3,14,27]. However, patients with large ischemic changes were excluded from these studies, and the incidence of FR and related factors when MT is performed in such patients remains unclear. It is clinically important to investigate predictors of FR, particularly in patients with large ischemic changes, as they are expected to have a higher likelihood of FR. In this study, we examined the risk factors for, and incidence of, FR after MT in patients with large ischemic cores.

MATERIALS AND METHODS

RESULTS

During the study period, 103 patients with large ischemic cores underwent MT for acute stroke. Nineteen patients were excluded for the following reasons: unsuccessful recanalization (n=9) or a pre-mRS score>3 before onset (n=10). Eighty-four patients fulfilled the inclusion criteria, of whom 57 (67.9%) were assigned to the FR group and 27 (32.1%) to the non-FR group (Fig. 1).

Fig. 1.

Flow diagram of this study. FR, futile recanalization; mRS, modified Rankin Scale; MT, mechanical thrombectomy

Compared with patients in the non-FR group, those in the FR group were significantly older (median 80 vs. 72 years, P=0.007), had significantly higher NIHSS scores (median 20 vs. 16, P=0.002), had significantly lower DWI-ASPECTS scores (median 4 vs. 5, P=0.046), and had a significantly higher number of passes (median 2 vs. 1, P=0.037) (Tables 1 and 2).

Table 1.

Comparisons of characteristics between futile recanalization (FR) and non-FR groups

Table 2.

Comparison of endovascular treatment outcomes between futile recanalization (FR) and non-FR groups

Multivariate analysis revealed that older age (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.01–1.18; P=0.011), concomitant diabetes (OR, 11.2; 95% CI, 1.13–111.1; P=0.012), DWI-ASPECTS (OR, 0.32; 95% CI, 0.11–0.79; P=0.012), and number of passes (OR, 1.91; 95% CI, 1.00–4.16; P=0.046) were determined to be independently associated with the occurrence of FR after MT in patients with a large ischemic core (Table 3).

Table 3.

Multivariable regression analysis for futile recanalization (FR)

Using the receiver operating characteristic curves from logistic regression analysis, the predictive accuracies of age, diabetes, dominant side, NIHSS score, DWI-ASPECTS score, number of passes, and symptomatic intracerebral hemorrhage (sICH) were identified. This model exhibited the best performance with an area under the curve of 0.86 (P<0.05).

DISCUSSION

MT has been shown to be more effective than medical therapy for acute ischemic stroke with a large ischemic core caused by LVO [2,4,13,16,24,25]. Conversely, previous studies have reported that the proportion of FR ranged from 49.7% to 66.6% in LVO of the anterior circulation with a large ischemic core [6,22], and the incidence of FR was also very high (approximately 68%) in the present study. Although meta-analyses of FR-related factors were performed [3,14], patients with low DWI-ASPECTS scores were excluded. In this study, older age, lower DWI-ASPECTS, concomitant diabetes, and an increased number of passes were independently associated with the occurrence of FR.

Our results demonstrated that the OR for FR was 1.08 per year of advancing age, with a cutoff of 72 years. Previous meta-analyses have confirmed that age is an important factor associated with FR, which is consistent with this result [3,14,15]. Kim et al. showed that older age is a risk factor for FR in cases with a large ischemic core [6]. Yi et al. reported that, among patients with a large ischemic core, those older than 68 years had a threefold higher risk of FR [22]. If similar results are reported in the future, the indications for MT may be reconsidered in older patients with large ischemic cores. The possible mechanisms include cerebrovascular self-regulation and collateral blood flow disorders caused by aging [10]. In addition, increased comorbidities, increased incidence of complications, and decreased rehabilitation efficiency are more likely to occur in older patients than in younger patients [8,15].

Results of this study revealed that DWI-ASPECTS score ≤3 was associated with FR. To the best of our knowledge, this is the first study to show an association between the DWI-ASPECTS and FR in LVO with a large ischemic core. In the post-hoc analysis of RESECU-Japan Limit, the efficacy of endovascular treatment was not demonstrated in the group with DWI-ASPECTS ≤3 compared to medical treatment [18]. In patients with large ischemic cores, a DWI-ASPECTS score of ≤3 may be specified as a cutoff point related to treatment outcomes in the future. Conversely, Yoshimoto et al. suggested that the threshold for ischemic core volume associated with poor prognosis is ≥71 mL and that a DWI-ASPECTS score of four points may be a cutoff point for treatment [23]. In the present study, we did not evaluate the volume of the ischemic core using perfusion imaging. Because we performed evaluations based on DWI-ASPECTS, it is important to note that there is a possibility of overestimating acute ischemic lesions in the perforating arterial region of the middle cerebral artery (MCA) compared with observations using computed tomography.

Diabetic complications were also associated with FR. Hyperglycemia in patients with acute ischemic stroke leads to mechanisms, such as altered blood–brain barrier permeability [12], increased intracellular acidosis due to the accumulation of lactic acid [11], and increased oxidative stress response [19]. Consequently, inflammatory responses are accelerated, leading to impaired vascular endothelial function. It also causes complications, such as reperfusion injury and hemorrhagic infarction [21]. Yi et al. also reported that diabetes was associated with FR after MT in patients with a large ischemic core [22]. Furthermore, elevated serum glucose levels on admission are associated with poor prognosis in patients with a large ischemic core [7]. However, in the present study, there was no correlation between blood glucose levels at admission and FR.

This study showed that an increased number of passes was associated with FR. The association between the number of passes and FR has been reported previously [1,9], and our earlier study showed similar results [17]. The first-pass effect has been shown to be associated with good clinical outcomes 90 days after MT [5]. The median number of passes in the non-FR group was one, suggesting a higher first-pass effect in that group. In general, an increased number of passes correlates with P2R; however, in this study, no correlation was found between the number of passes and P2R or O2R over time. In addition, an increased number of passes has been associated with hemorrhagic infarction [26]. In this study, the higher percentage of sICH in the FR group suggests an association with the number of passes.

To confirm predictive factors, this research must be further developed, which requires randomized controlled trials. However, identifying these factors might lead to the following medical ethical issue: The problem is that MT would not be presented as a treatment option for patients with low therapeutic efficacy. As the aging population progresses, the issue of patient selection could become more significant.

The present study had several limitations. The first was its three-center, retrospective, observational design. As such, prospective and multicenter studies are required. Second, the small sample size may have limited statistical power and may have introduced selection bias and errors. Third, this study did not evaluate ischemic core volume using perfusion images, assessing only DWI-ASCPTES. Ischemic core volume from perfusion images could potentially be a contributing factor to FR, but this data was lacking in this study.

CONCLUSIONS

Our results demonstrate that the incidence of FR was high, affecting nearly 70% of patients with large ischemic cores. Older age, concomitant diabetes, lower DWI-ASPECTS score, and an increased number of passes were independent predictors of FR.

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