Abstract
Objective:
Malignant brain edema (MBE) after mechanical thrombectomy (MT) for anterior circulation occlusion leads to poor outcomes. Although contrast agent extravasation (CAE) indicates blood-brain barrier disruption, its predictive value for MBE remains uncertain. This study evaluated whether the CAE—Alberta Stroke Program Early CT Score (CAE-ASPECTS) derived from dual-source computed tomography (CT) could predict MBE after anterior circulation recanalization with MT.
Methods:
Patients with anterior circulation occlusion undergoing mechanical thrombectomy (MT) were divided into malignant brain edema (MBE) and non-MBE groups. The primary outcome was to determine whether postoperative CAE-ASPECTS scores predicted MBE. The secondary outcomes were to identify factors influencing malignant brain edema and to examine the association between CAE-ASPECTS and 90-day modified Rankin Scale (mRS) and 72-hour intracerebral hemorrhage.
Results:
The MBE group had a significantly lower median postoperative CAE-ASPECT score. After adjusting for confounding factors, CAE-ASPECTS remained independently associated with MBE. Lower CAE-ASPECTS, higher National Institutes of Health Stroke Scale (NIHSS) score, and longer operative time were associated with increased MBE risk. The regression model yielded a predictive accuracy of 93%. Favorable 90-day mRS (0 to 2) was more common in the non-MBE group, and mortality was lower. Finally, cerebral hemorrhagic transformation was inversely correlated with CAE-ASPECTS.
Conclusion:
Lower CAE-ASPECTS scores were significantly correlated with increased MBE incidence. Moreover, CAE-ASPECTS was an independent predictor of MBE, while cerebral hemorrhage transformation was negatively correlated with the CAE-ASPECTS after successful thrombectomy. Finally, CAE-ASPECTS, preoperative NIHSS, ASPECTS, and operative time collectively predict MBE with 93% sensitivity, providing a useful imaging biomarker for post-MT risk assessment.
Key Words: malignant brain edema, anterior circulation large vessel occlusion, mechanical thrombectomy, contrast extravasation
Stroke remains the second-leading cause of death and disability worldwide, with the heaviest burden in low- and middle-income countries. Ischemic strokes account for ∼87% of all strokes, of which 10% to 20% involve large vessel occlusions (LVOs).1 In China, stroke is the leading cause of both disability and death.2,3
Intravenous thrombolysis with alteplase within 4.5 hours of onset reduces disability in ischemic stroke;4 however, only about 21% of patients with proximal occlusion achieve recanalization following this therapy.5 For patients with LVO, mechanical thrombectomy (MT) within 6 hours can improve outcomes, as demonstrated in pivotal 2015 trials.6–10 2018 Later studies, such as the DAWN and DEFUSE 3 trials, further expanded the therapeutic time window for MT.11,12 Despite these advances, half of patients treated with MT remain disabled, as shown in HERMES.13,14
Several factors contribute to a poor prognosis after MT, including older age, brain reserve, blood pressure, glucose level, infarct core size, and collateral circulation.15 Although good collateral flow is associated with a better prognosis and a lower risk of hemorrhagic transformation,16 HERMES demonstrated no significant difference between preoperative imaging selection and overall prognosis.14
The development of malignant brain edema (MBE) after MT remains a major clinical concern and a predictor of poor prognosis.17 While decompressive surgery within 48 hours can reduce mortality and functional recovery,18 early identification of patients at risk is crucial for timely intervention.
At our center, we observed that contrast agent extravasation (CAE) on postoperative imaging often coincided with hemorrhage and cerebral edema, suggesting a possible link between CAE and MBE. However, whether contrast extravasation after MT can predict intracerebral hemorrhage or MBE remains to be verified.
Therefore, this study investigated the relationship between postoperative contrast extravasation, clinical features, and the development of MBE after MT.
METHODS
Trial Design and Oversight
Participants
We enrolled patients who underwent MT at Zigong Fourth People’s Hospital between January 2018 and August 2024. This study was approved by the hospital ethics committee, and all surgeries were performed with informed consent from the patients’ guardians.
Eligible patients met the following criteria: (1) a prestroke modified Rankin Scale (mRS) <2; (2) nonenhanced computed tomography (CT)—Alberta Stroke Program Early CT Score (ASPECTS) ≥6 consistent with the SELECT study imaging criteria for thrombectomy in the extended treatment window;19 (3) anterior circulation vessel occlusion involving the internal carotid artery (ICA) or the M1 to M2 segments of the middle cerebral artery; (4) aged 18 years or younger; (5) successful reperfusion defined as a Thrombolysis in Cerebral Infarction (TICI) grade of 2b or 3 after MT; and (6) immediate postoperative dual-source CT indicating a cerebral hemorrhage.
Imaging Evaluation
All patients underwent preoperative imaging evaluation, including a nonenhanced CT examination; for those in the late treatment window, additional CT perfusion, CT angiography, or digital subtraction angiography was performed to confirm the occlusion site. Baseline nonenhanced CT images were independently reviewed by 2 senior neuroimaging specialists to determine the ASPECTS.20
Postoperative imaging was evaluated using dual-source CT. Three types of sequential images were obtained: fusion images (MIXs), virtual noncontrast images (VNCs), and iodine overlay maps (IOMs). IOMs staining indicated CAE, whereas acute hemorrhage appeared only on VNC images. The CAE was evaluated using the CAE-ASPECTS and scored as described by Puetz et al21 (Fig. 1). In ASPECTS, the MCA is divided into 10 regions (internal capsule, basal ganglia, caudate nucleus, and M1 to M6), each assigned 1 point. One point was subtracted for each region showing iodine staining, resulting in a CAE-ASPECTS score ranging from 0 to 10 (Figs. 2, 3).
FIGURE 1.
Axial computed tomography (CT) cuts of the ganglionic ASPECTS level M1 to M3, insula (I), lentiform nucleus (L), caudate nucleus (C), and posterior limb of the internal capsule (IC). (A) Preganglionic ASPECTS level M4 to M6. (B) Definition of CAE-ASPECTS: the ASPECTS scoring allows the MCA territory 10 regions (internal capsule, basal ganglia, caudate nucleus, M1, M2, M3, M4, M5, and M6). The scoring area of CAE-ASPECTS is the same as that of ASPECTS, which is divided into 10 points. To compute CAE-ASPECTS, both normalized levels (ganglionic and supraganglionic) were included, while all axial cuts of the middle artery region were included at both levels. It is necessary to visualize all regions and the cuts with a 4 to 5 mm slice thickness. Contrast agent extravasation should be visible on at least 2 adjacent cuts. The virtual image and ideogram excluded bleeding and calcifying lesions compared with a preoperative brain CT scan.
FIGURE 2.
Right posterior internal carotid artery occlusion, recanalization after mechanical thrombectomy, TICI grade 3. (A, B) Immediately after surgery, dual-energy brain CT indicated a high-density image on the right side, the iodine map showed a high-density image, and the virtual image did not show a high-density image, so contrast agent exudation was considered. According to the distribution area of the ASPECT score, the score of the contrast agent-oozing area is 1, and the CAE-ASPECTS is 1. (C–F) Brain CT showed significant midline deviation within 24 hours after surgery. (G)
FIGURE 3.
left posterior internal carotid artery occlusion, recanalization after mechanical thrombectomy, TICI grade 3. (A, B) Immediately after surgery, dual-energy brain CT indicated a high-density image on the left side, the iodine map showed a high-density image, and the virtual image did not show a high-density image, so contrast agent exudation was considered. According to the distribution area of the ASPECT score, the score of the contrast agent-oozing area is 9, and the CAE-ASPECTS is 9. (C–E) Brain CT showed no midline deviation. (F)
Collateral circulation was assessed using the Arterial Stenosis Index/Signal Intensity Ratio (ASINT/SIR),22 while postoperative reperfusion status was evaluated using the modified TICI (mTICI) grading system.22
Data Collection
All patient data were retrospectively reviewed. The collected variables included medical history, National Institutes of Health Stroke Scale (NIHSS) score, Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification, preoperative ASPECTS score, ASINT/SIR, postoperative TICI score, postoperative CAE-ASPECTS score, occlusion site, MBE, and 90-day mRS score.
MBE was defined as:23 (1) Parenchymal hypodensity involving at least 50% of the affected hemisphere with signs of local brain swelling; and (2) a midline shift of ≥5 mm at the septum pellucidum, as measured within 72 hours after thrombectomy. The mTICI grade described the degree of reperfusion, ranging from no antegrade perfusion beyond the occlusion (grade 0) to complete and normal reperfusion comparable to the contralateral hemisphere (grade 3). Grade 0 was defined as no antegrade perfusion in the occluded vessel region, grade 1 as partial passing of the contrast agent passing beyond the initial occlusion but failing to fill the obstruction branches, grade 2a as <2/3 of the vascular territory, grade 2b as >2/3 of the vascular territory showing slower than normal antegrade flow; and grade 3 as complete reperfusion of the entire territory similar to that of the contralateral unaffected vessels. ASINT/SIR was defined as grade 0 in cases with no visible collateral flow in the ischemic area; grade 1 as slow collateral flow around the ischemic site with partial defect persistence; grade 2 as rapid collateral flow around the ischemic site and partial defects in the ischemic territory; grade 3 as slow collateral flow with complete flow in the ischemic territory during the late venous phase; and grade 4 as complete and rapid reverse perfusion of collaterals to the entire ischemic territory.
Study Outcomes
The primary outcome was whether postoperative CAE-ASPCETS scores could predict MBE occurrence. The secondary outcomes were the identification of factors influencing MBE and between CAE-ASPECTS, 90-day mRS, and 72-hour intracerebral hemorrhage (Fig. 4).
FIGURE 4.
Clinical research roadmap. ASINT/SIR indicates arterial stenosis index/signal intensity ratio; ASPECTS, Alberta Stroke Program Early CT Score; CAE, contrast agent extravasation—Alberta Stroke Program Early CT Score; MBE, malignant brain edema; mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale; TICI, Thrombolysis in Cerebral Infarction; TOAST, Trial of Org 10172 in Acute Stroke Treatment.
Statistical Analysis
The patients were divided into non-MBE and MBE groups. Continuous variables are presented as means±SD or medians (interquartile range, IQR). Categorical variables are presented as percentages. Continuous variables were analyzed using the Mann-Whitney U test. Categorical variables were assessed using χ2 and Fisher exact tests. MBE was investigated using binary logistic regression to evaluate the association between factors and MBE presence, and univariate analyses were entered into the logistic regression with P<0.1. All statistical analyses were performed using IBM SPSS Statistics for Windows, version 26.0.
RESULTS
Baseline Characteristics
Between January 2018 and August 2024, 227 patients underwent anterior circulation thrombectomy. Of these,8 exceeded 24 hours, 28 had a final mTICI grade <2b after the surgery, and 13 exhibited intracranial hemorrhage on dual-source CT performed immediately postoperatively. Therefore, 178 patients met the inclusion criteria. The mean age was 70.00±11.24 years, and 75 (42.1%) were male. The MBE and non-MBE groups included 40 and 138 patients, respectively.
The non-MBE and MBE groups showed no significant differences in mean age (70.17±11.38 vs. 69.43±10.85, P=0.714), sex distribution (42% vs. 42.5% male, P=0.958), baseline median (IQR) systolic blood pressure (SBP) [153 (132 to 165) vs. 157 (136 to 178) mm Hg, P=0.104] and diastolic blood pressure (DBP) [81 (73 to 90) vs. 90 (78 to 96) mm Hg, P=0.121], median (IQR) diabetes mellitus rates [14% (11 to 18) vs. 17% (14 to 20), P=0.232], median (IQR) onset-to-reperfusion time [404 (313 to 526) vs. 400 (339.5 to 529) min, P=0.519], and intravenous thrombolysis rates (39.1% vs. 42.5%, P=0.702). The stroke etiology distribution did not differ significantly between the non-MBE and MBE groups (left atrial appendage: 26.8% vs. 20%; cardioembolic: 71.7% vs. 72.5%; and other: 1.4% vs. 7.5%) (P=0.189).
Compared with the non-MBE group, patients in the MBE group had significantly higher baseline NIHSS scores [17 (14 to 20) vs. 14 (11 to 18), P=0.000], significantly lower baseline ASPECT scores [8 (7 to 9) vs. 9 (8 to 10), P=0.000], and significantly lower postoperative CAE-ASPECTS [5 (2 to 7) vs. 9 (7 to 10), P=0.000]. The occlusion sites also differed between the non-MBE and MBE groups (ICA: 38.4% vs. 60%, M1: 47.1% vs. 32.5%, and M2: 14.5% vs. 7.5%; P=0.049). MBE patients demonstrated poorer collateral circulation (grade 0, 87.5% vs 60.1%; grade 1, 2.5% vs 14.4%; grade 2, 5.0% vs 12.3%; and grade 3, 5.0% vs 13.0%; P=0.014) (Table 1).
TABLE 1.
Baseline Characteristics
| Clinical characteristics |
All patients (n=178), n (%) or mean±SD |
Non-MBE group (n=138), n (%) or mean±SD | MBE group (n=40), n (%) or mean±SD | P |
|---|---|---|---|---|
| Age (y) | 70.00±11.24 | 70.17±11.38 | 69.43±10.85 | 0.714 |
| Male | 75 (42.1) | 58 (42) | 17 (42.5) | 0.958 |
| median (IQR) | ||||
| Baseline SBP, mm Hg | 154 (132-167) | 153 (132-165) | 157 (136-178) | 0.104 |
| Baseline DBP, mm Hg | 84 (74-92) | 81 (73-90) | 90 (78-96) | 0.121 |
| Diabetes mellitus (yes) | 30 (16.9) | 20 (14.5) | 10 (25.0) | 0.232 |
| Baseline NIHSS score | 15 (12-19) | 14 (11-18) | 17 (14-20) | 0.000 |
| Baseline ASPECT score | 9 (8-10) | 9 (8-10) | 8 (7-9) | 0.000 |
| Stroke cause | 0.189 | |||
| LAA | 45 (25.2) | 37 (26.8) | 8 (20.0) | |
| Cardioembolic | 128 (71.9) | 99 (71.7) | 29 (72.5) | |
| Other cause | 5 (2.8) | 2 (1.4) | 3 (7.5) | |
| Occlusion site | 0.049 | |||
| ICA | 77 (43.3) | 53 (38.4) | 24 (60.0) | |
| M1 | 78 (43.8) | 65 (47.1) | 13 (32.5) | |
| M2 | 23 (12.9) | 20 (14.5) | 3 (7.5) | |
| OTR (min) mean (IQR) | 402 (321-526) | 404 (313-526) | 400 (339.5-529) | 0.519 |
| Intravenous thrombolysis | 71 (39.9) | 54 (39.1) | 17 (42.5) | 0.702 |
| Collateral score | 0.014 | |||
| Grade 0 | 118 (66.2) | 83 (60.1) | 35 (87.5) | |
| Grade 1 | 21 (11.7) | 20 (14.4) | 1 (2.5) | |
| Grade 2 | 19 (10.6) | 17 (12.3) | 2 (5) | |
| Grade 3 | 20 (11.2) | 18 (13) | 2 (5) | |
| CAE-ASPECTS (IQR) | 8 (6-10) | 9 (7-10) | 5 (2-7) | 0.000 |
| 90 d mRS | 0.000 | |||
| mRS 0 | 34 (19.1) | 34 (24.6) | 0 | |
| mRS 1 | 29 (21.9) | 39 (28.3) | 0 | |
| mRS 2 | 13 (7.3) | 12 (8.7) | 1 (2.5) | |
| mRS 3 | 15 (8.4) | 15 (10.9) | 0 | |
| mRS 4 | 23 (12.9) | 22 (15.9) | 1 (2.5) | |
| mRS 5 | 16 (9.0) | 9 (6.5) | 7 (17.5) | |
| Mortality at 90 d | 38 (21.3) | 7 (5.1) | 31 (77.5) | |
| Heidelberg classification | 0.051 | |||
| HI1 | 15 (8.4) | 11 (7.9) | 4 (10) | |
| HI2 | 6 (3.3) | 5 (3.6) | 1 (2.2) | |
| PH1 | 3 (1.6) | 3 (2.1) | 1 (2.2) | |
| PH2 | 4 (2.2) | 1 (0.7) | 3 (7.5) | |
| Remote ICH | 20 (11.2) | 11 (7.9) | 9 (22.5) | |
Outcomes
Postoperative CAE-ASPECTS were significantly lower in the MBE group [3 (1 to 4) vs. 8 (6.25 to 9), P=0.000]. After adjusting for confounding factors (CAE-ASPECTS, preoperative NIHSS, TOAST, ASINT/SIR, occlusion site, preoperative ASPECTS, and operation time), lower CAE-ASPECTS, higher NIHSS, lower ASPECTS, and longer operation time independently predicted MBE. The logistic regression model demonstrated 93% accuracy. Specifically, increased MBE risk was associated with lower CAE-ASPECTS [odds ratio (OR)=0.652; 95% CI, 0.530-0.802; P=0.000], higher NIHSS scores (OR, 1.159; 95% CI, 1.013-1.326; P=0.032), longer operative time (OR, 1.025; 95% CI, 1.012-1.038; P=0.000), and higher preoperative ASPECT scores (OR, 0.454; 95% CI, 0.298-0.690; P=0.000) (Table 2).
TABLE 2.
Univariate Analysis and Multivariate Analysis of Factors Influencing the MBE
| Clinical and imaging characteristics | Univariate analysis | Multivariate analysis | ||
|---|---|---|---|---|
| OR (95% CI) | P | OR (95% CI) | P | |
| Sex | 1.019 (0.500-2.078) | 0.958 | ||
| Age | 0.994 (0.964-1.026) | 0.713 | ||
| Pro-NIHSS | 1.155 (1.069-1.247) | 0.000 | 1.159 (1.013-1.326) | 0.032 |
| Pro-ASPECTS | 0.570 (0.439-0.739) | 0.000 | 0.455 (0.298-0.690) | 0.000 |
| TOAST | ||||
| Atherosclerosis | 0.149 | 0.729 | ||
| Embolism | 0.144 (0.021-1.009) | 0.051 | 0.353 (0.016-7.769) | 0.509 |
| Other cause | 0.195 (0.031-1.225) | 0.081 | 0.295 (0.014-6.063) | 0.429 |
| Intravenous thrombolysis | 1.150 (0.563-2.348) | 0.702 | ||
| OTR | 1.000 (0.999-1.002) | 0.795 | ||
| Occlusive site | ||||
| ICA | 0.040 | 0.845 | ||
| M1 | 3.019 (0.818-11.141) | 0.097 | 0.779 (0.128-4.745) | 0.786 |
| M2 | 1.231 (0.316-4.799) | 0.765 | 0.599 (0.092-3.914) | 0.792 |
| Operation time | 1.025 (1.008-1.023) | 0.000 | 1.025 (1.012-1.038) | 0.000 |
| ASITN/SIR | ||||
| 0 | 0.031 | 0.411 | ||
| 1 | 3.795 (0.836-17.237) | 0.084 | 1.585 (0.200-12.574) | 0.663 |
| 2 | 0.450 (0.038-5.392) | 0.529 | 0.173 (0.004-7.017) | 0.353 |
| 3 | 1.059 (0.134-8.383) | 0.957 | 0.287 (0.017-4.845) | 0.387 |
| CAE-ASPECTS | 0.610 (0.518-0.719) | 0.000 | 0.652 (0.530-0.802) | 0.000 |
Receiver operating curve (ROC) analysis test showed that CAE-ASPECTS had the highest diagnostic performance [area under the curve (AUC) 0.814, 95% CI, (0.724-0.903), P=0.000] with a Yoden index of 0.562 and an optimal cutoff of 6.5.
For preoperative ASPECTS, the AUC was 0.697 (95% CI, 0.599-0.796; P<0.001) with a Youden index of 0.316 and a cutoff of 7.5.
For the preoperative NIHSS score, the AUC was 0.700 (95% CI, 0.614-0.786; P<0.001) with a Youden index of 0.316 and a cutoff of 15.5.
For operation time, the AUC was 0.721 (95% CI, 0.631-0.811; P<0.001) with a Youden index of 0.352 and a cutoff of 113 minutes.
Combined, CAE-ASPECTS, preoperative ASPECTS, NIHSS, and operation time predicted postoperative MBE with 85% sensitivity and 85.5% specificity (Fig. 5, Tables 3–4).
FIGURE 5.
CEA-ASPECT, Pro-NHISS, Pro-ASPECTS, and Operation Time ROC Curve. Y-axis = Sensitivity; X-axis = 1-Specificity.
TABLE 3.
CEA-ASPECTS, Pro-NIHSS, Pro-NIHSS, and Operation Time Area Under the Curve
| Variables | Area | 95% CI | P |
|---|---|---|---|
| CAE-ASPECTS | 0.814 | 0.724-0.903 | 0.000 |
| Pro-ASPECT | 0.697 | 0.599-0.796 | 0.000 |
| Pro-NIHSS | 0.700 | 0.614-0.786 | 0.000 |
| Operation time | 0.721 | 0.631-0.811 | 0.000 |
TABLE 4.
CAE-ASPECTS and Pro-NIHSS Cutoff Criterion
| Variables | Cutoff, n (%) | Sensitivity, n (%) | Specificity, n (%) | Youden index |
|---|---|---|---|---|
| CAE-ASPECTS | 4.5 | 87 | 87 | 0.562 |
| Pro-NIHSS | 15.5 | 72.5 | 65.2 | 0.377 |
| Pro-ASEPCT | 7.5 | 42.5 | 89.1 | 0.316 |
| Operation time | 113 | 70 | 65.2 | 0.352 |
At 90 days, compared with the MBE group, favorable outcomes (mRS 0 to 2) were significantly more frequent in the non-MBE group (61.6% vs. 2.5%, P=0.000), while the mortality rate was significantly lower (5.1% vs. 77.5%, P=0.000) (Fig. 6, Table 1). Multivariate logistic regression incorporating CAE-ASPECTS confirmed significant associations with hemorrhagic transformation subtypes: type 1 (B −0.164, OR 0.848, 95% CI, 0.726-0.992, P=0.039), type 2 (B −0.342, OR 0.710, 95% CI, 0.523-0.963, P=0.028), and type 3 (B −0.289, OR 0.749, 95% CI, 0.638-0.879, P=0.000) (Table 5).
FIGURE 6.
MBE with 90-day mRS. Y-axis = 90-day mRS Score; X-axis = Percentage (%).
TABLE 5.
Factors Influencing Cerebral Hemorrhage Transformation after Thrombectomy
| Hemorrhagic transformation subtype | CEA-ASPECTS | ||
|---|---|---|---|
| B | OR (95% CI) | P | |
| Class 1 | −0.164 | 0.848 (0.726-0.992) | 0.039 |
| Class 2 | −0.342 | 0.710 (0.523-0.963) | 0.028 |
| Class 3 | −0.289 | 0.749 (0.638-0.879) | 0.000 |
DISCUSSION
This study investigated risk factors for MBE after MT in patients with anterior circulation LVO. Our results revealed that patients who developed MBE had significantly lower postoperative CAE-ASPECT. Multivariable analysis demonstrated that CAE-ASPECTS, preoperative NIHSS score, preoperative ASPECTS, and operation time independently predicted MBE, achieving a predictive accuracy of 93%. ROC analysis yielded cutoff values of 6.5, 7.5, 15.5, and 113 for CAE-ASPECTS, preoperative NIHSS score, preoperative ASPECTS, and operation time, respectively, with 85% sensitivity and 85.5% specificity. Furthermore, 90-day outcomes were poorer among patients with MBE, with significantly lower functional independence (mRS 0 to 2) and higher mortality. Logistic regression showed a negative correlation between CAE-ASPECTS and hemorrhagic transformation.
The blood-brain barrier (BBB) is a multicellular interface separating the nervous system from systemic circulation, acting as a barrier and regulating nutrient metabolism. Vascular edema is caused by increased BBB permeability following cerebral infarction.24 Ischemia-reperfusion injury due to rapid vascular revascularization can cause BBB breakdown via cascading events, including inflammation, free radical formation, and hemodynamic disturbances.25 Disrupted blood flow after cerebral infarction leads to impaired oxygen and nutrient supply and increased permeability due to BBB dysfunction.26 In the present study, iodine contrast exudates in brain tissue after thrombectomy reflected BBB breakdown, supporting that the degree of contrast leakage parallels the severity of BBB dysfunction and edema formation.
Although MT improves outcomes in acute cerebral stroke caused by intracranial artery occlusion, nearly half of patients do not achieve good functional outcomes despite vascular recanalization. Previous studies have implicated factors such as collateral circulation, preoperative ASPECTS, and NIHSS score as potential causes of poor outcomes. Cerebral reperfusion edema is a major cause of adverse outcomes.15 Life-threatening herniation occurs in 1% to 10% of patients with supratentorial infarction,27 with a nearly 80% mortality rate.28 Successful reperfusion reduces cerebral edema and rescues ischemic brain tissue; however, 46.8% of patients show a midline shift (MLS) after recanalization in a secondary analysis of the MR CLEAN Trial.29 However, MBE still occurs in some patients despite vascular recanalization, with consequent high mortality risk. The current effective treatment for MBE is early (48 h) decompressive craniotomy.18,30 Early identification and intervention are key to improving patient prognosis. While blood glucose level, NIHSS score, collateral circulation, anesthesia, preoperative ASPECTS, reperfusion time, and occlusion site are correlated with brain edema, the factors influencing brain edema after vascular recanalization have not been analyzed.29 A single-center retrospective analysis reported the association of that vessel occlusion sites and collateral status with MBE following MT for anterior circulation LVO.23
Young age, high NIHSS scores, and lower ASPECTS scores,31 as well as higher baseline glucose level32 and poor collateral circulation,33 are predictive markers of MBE. Cerebral edema can be reduced after successful reperfusion;29 however, few studies have predicted malignant brain edema after successful reperfusion. Our study found that the preoperative NIHSS score, preoperative ASPECT score, operative time, and CAE-ASPECTS were correlated with MBE in anterior circulation LVO, while cerebral hemorrhage transformation was negatively correlated with CAE-ASPECTS after successful thrombectomy. This may reflect differences in MBE between cases with successful anterior circulation LVO recanalization and those in which recanalization failed. Postoperative MBE was significantly associated with mortality and poor mRS, and early MBE identification and treatment are key to reducing mortality and adverse prognosis. The results of our study demonstrated that the preoperative NIHSS score, preoperative ASPECTS, operative time, and CAE-ASPECTS could predict early-stage postoperative MBE formation after anterior circulation LVO recanalization, providing help for effective early intervention for MBE to reduce mortality and poor prognosis.
Despite the novel findings, this study has several limitations, including the small sample size. Large, multicenter, prospective cohort studies are needed to validate these findings and refine predictive thresholds.
In conclusion, postoperative CAE-ASPECTS scoring offers a practical tool for predicting malignant brain edema after thrombectomy, enabling early risk stratification and guiding perioperative management to improve prognosis.
Footnotes
This study was supported by the Zigong City Health Commission.
The authors declare no conflict of interest.
Contributor Information
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