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ORIENTAL MEVO

Year of Publication: 2025

Authors: Raul Nogueira, Xiao-Zhong Jing, Wei Hu

Journal: Not published yet

Clinical Question

Does thrombectomy improve functional outcomes compared to medical management alone in patients with medium vessel occlusion stroke and moderate-to-severe deficits (NIHSS ≥6) presenting within 24 hours?

Bottom Line

Thrombectomy significantly improved functional independence (mRS 0–2) and excellent outcome (mRS 0–1) at 90 days compared to medical management alone in MeVO stroke patients with NIHSS ≥6, with an NNT of 8 and no significant increase in sICH or mortality. Benefit was not seen in the NIHSS <8 subgroup.

        Major Points
        First positive RCT for thrombectomy in MeVO stroke, targeting patients with NIHSS ≥6 — a key design difference from neutral trials DISTAL and ESCAPE-MeVO.
Primary endpoint of ordinal mRS shift violated the proportional odds assumption; prespecified alternative of 90-day mRS 0–2 showed significant benefit (58.6% vs 46.6%; aRR 1.24, P=0.004).
Median 90-day mRS was 2 in thrombectomy group vs 3 in medical management group.
Excellent outcome (mRS 0–1) also significantly favored thrombectomy (48.9% vs 33.2%; aRR 1.47, P<0.001).
Successful reperfusion (eTICI 2b–3) achieved in 74.4% of thrombectomy patients.
Vessel patency at 24–72 hours was 82.1% vs 46.2% favoring thrombectomy.
sICH was numerically higher but not statistically different (4.7% vs 2.2%).
Mortality was comparable (11.1% vs 10.2%).
No benefit of thrombectomy observed in NIHSS <8 subgroup, corroborating findings from ESCAPE-MeVO and DISTAL.
ACA and PCA occlusions combined exceeded 40% of the cohort, indicating substantial posterior and anterior distal territory representation.
IVT rates were below 40% in both groups.
NNT of 8 for functional independence; per 100 treated, 54 had less disability and 12 additional achieved mRS 0–2.

      

Design

Study Type: Investigator-initiated, prospective, open-label, randomized controlled trial

Randomization: 1

Blinding: Open-label (unblinded)

Follow-up Duration: 90 days

Centers: 48

Countries: China

Sample Size: 563

Analysis: Intention-to-treat. Ordinal mRS shift prespecified as primary but proportional odds assumption was violated, triggering prespecified alternative of mRS 0–2 as primary. Adjusted risk ratios reported.

Inclusion Criteria

Ischemic stroke due to MeVO (co-dominant or non-dominant M2, M3 of MCA; A1, A2, A3 of ACA; P1, P2, P3 of PCA)
Baseline NIHSS score ≥6
Presentation within 24 hours of symptom onset

Baseline Characteristics

Characteristic	Control	Active
N	283	280
Median NIHSS	~10	~10
Most common site	M2 MCA	M2 MCA
ACA + PCA occlusions	>40%	>40%
IVT rate	<40%	<40%
eTICI 2b–3		74.4%

Arms

Field	Thrombectomy + Medical Management	Control
Intervention	Mechanical thrombectomy plus standard medical management	Standard medical management alone (including IVT when eligible)
Duration

Outcomes

Outcome	Type	Control	Intervention	HR / OR / RR	P-value
90-day mRS 0–2 (prespecified alternative after proportional odds violation for ordinal mRS shift)	Primary	46.6%	58.6%	9	P=0.004
Excellent outcome (mRS 0–1 at 90 days)	Secondary	33.2%	48.9%	aRR 1.47	P<0.001
Vessel patency at 24–72 hours	Secondary	46.2%	82.1%
Ordinal mRS shift (prespecified primary — invalidated)	Secondary	Median mRS 3	Median mRS 2	Proportional odds assumption violated; common OR not reported
Symptomatic ICH	Adverse	2.2%	4.7%		NS
Mortality	Adverse	10.2%	11.1%		NS
Radiological ICH (24–72h)	Adverse	6.0%	11.4%

Subgroup Analysis

No significant benefit of thrombectomy in patients with NIHSS <8, consistent with findings from the negative ESCAPE-MeVO and DISTAL trials. This supports targeting thrombectomy to MeVO patients with moderate-to-severe deficits.

Criticisms

Open-label design with no blinding of patients, clinicians, or outcome assessors.
Proportional odds assumption violated for the prespecified primary endpoint (ordinal mRS shift), requiring switch to the prespecified alternative (mRS 0–2).
Conducted exclusively in China (48 sites), which may limit generalizability to other healthcare systems and ethnic populations.
IVT rates below 40% in both groups — lower than many Western practice settings.
Successful reperfusion rate (eTICI 2b–3) of 74.4% is lower than in LVO thrombectomy trials (typically >85%).
Baseline characteristics details limited (derived from conference presentation, not full manuscript).
ACA and PCA occlusions made up >40% of the cohort, mixing heterogeneous vascular territories.
No NIHSS ≥6 threshold validation as the optimal cutoff for MeVO thrombectomy benefit.
Numerically higher sICH (4.7% vs 2.2%) and radiological ICH (11.4% vs 6.0%) in thrombectomy arm, though not statistically significant.
Full manuscript with detailed baseline tables, subgroup analyses, and per-protocol results not yet available.

Based on: ORIENTAL MEVO (Not published yet, 2025)

Authors: Raul Nogueira, Xiao-Zhong Jing, Wei Hu

Content summarized and formatted by NeuroTrials.ai.

ORIENTAL-MeVO

(2026)

Objective

To determine whether endovascular thrombectomy improves functional outcomes in patients with acute ischemic stroke due to medium-vessel occlusion and moderate-to-severe deficits.

Study Summary

• Functional independence (mRS 0-2) at 90 days: 58.6% thrombectomy vs 46.6% control (adjusted rate ratio 1.24, 95% CI 1.07-1.44, P=0.004)
• Symptomatic intracranial hemorrhage: 4.7% thrombectomy vs 2.2% control
• 90-day mortality: 11.1% thrombectomy vs 10.2% control
• Successful reperfusion (eTICI 2b50-3) achieved in 74.4% of thrombectomy patients

Intervention

Endovascular thrombectomy (stent retrievers, aspiration, angioplasty, stents, or intraarterial thrombolysis at operator's discretion) plus standard medical management vs standard medical management alone.

Inclusion Criteria

Adults ≥18 years with pre-stroke mRS 0-2, NIHSS ≥6, presenting within 24 hours of last known well, with occlusion of M2/M3 MCA, A1/A2/A3 ACA, or P1/P2/P3 PCA; <50% ischemic involvement on imaging or mismatch ratio >1.4 with penumbra ≥10 ml.

Study Design

Arms: Endovascular thrombectomy + medical management (n=280) vs Medical management alone (n=283)

Patients per Arm: 280 vs 283

Outcome

• Functional independence at 90 days: 58.6% vs 46.6% (adjusted RR 1.24, 95% CI 1.07-1.44, P=0.004)
• Symptomatic intracranial hemorrhage: 4.7% vs 2.2%
• 90-day mortality: 11.1% vs 10.2%
• Thrombectomy improved functional outcomes but at cost of higher sICH risk

Bottom Line

In patients with acute ischemic stroke due to medium-vessel occlusion and moderate-to-severe deficits (NIHSS ≥6), endovascular thrombectomy increased the likelihood of functional independence at 90 days compared with medical management alone (58.6% vs 46.6%), though at the cost of more symptomatic intracranial hemorrhage (4.7% vs 2.2%).

Major Points

First positive randomized trial of endovascular thrombectomy for medium-vessel occlusion strokes
Functional independence (mRS 0-2) at 90 days was significantly higher with thrombectomy (58.6% vs 46.6%, adjusted RR 1.24, 95% CI 1.07-1.44, P=0.004)
Selective enrollment of patients with moderate-to-severe deficits (NIHSS ≥6) may explain divergence from prior neutral trials
Symptomatic intracranial hemorrhage was more than 2-fold higher with thrombectomy (4.7% vs 2.2%)
Mortality at 90 days was similar between groups (11.1% vs 10.2%)
Successful reperfusion (eTICI 2b50-3) achieved in 74.4% of thrombectomy patients
The proportional-odds assumption was violated, so prespecified dichotomized mRS 0-2 outcome was used as primary

Study Design

Study Type: Investigator-initiated, prospective, open-label, multicenter, randomized controlled trial with blinded outcome assessment
Randomization: Yes
Blinding: Open-label treatment with blinded outcome assessment (PROBE design)
Sample Size: 564
Follow-up: 90 days
Centers: 48
Countries: China

Primary Outcome

Definition: Functional independence (modified Rankin scale score of 0, 1, or 2) at 90 days. Originally planned as ordinal shift in mRS, but proportional-odds assumption was violated, so prespecified dichotomized outcome was used.

Control	Intervention	HR/OR	P-value
46.6%	58.6%	- (1.07 to 1.44)	0.004

Limitations & Criticisms

Single-country trial conducted entirely in China — generalizability to other populations and healthcare systems may be limited
Open-label design (only outcome assessment was blinded)
Lower-than-expected complete reperfusion rate (only 5.8% achieved eTICI 3 on initial angiography)
Imbalance in occlusion sites between groups (M2 more common in thrombectomy group, M3 more common in control)
Imbalance in antiplatelet therapy use (67.1% thrombectomy vs 77.4% control)
Higher rate of symptomatic intracranial hemorrhage requires risk-benefit discussion
Original ordinal shift analysis could not be performed due to violation of proportional-odds assumption

Citation

N Engl J Med 2026;394:1894-904

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ORIENTAL MEVO

ORIENTAL MEVO

Clinical Question

Bottom Line

Major Points

Design

Inclusion Criteria

Baseline Characteristics

Arms

Outcomes

Subgroup Analysis

Criticisms

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