ORIENTAL MEVO
ORIENTAL MEVO
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
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
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