ROADSTER 2 Early Outcomes
Early Outcomes in the ROADSTER 2 Study of Transcarotid Artery Revascularization in Patients With Significant Carotid Artery Disease
Clinical Question
What is the safety and efficacy of transcarotid artery revascularization (TCAR) performed by a broad group of physicians with variable TCAR experience using the ENROUTE Transcarotid Stent and Neuroprotection System?
Bottom Line
TCAR with the ENROUTE system demonstrates excellent early outcomes with high technical success (99.7%) and low stroke (0.6% per-protocol) and death rates (0.2% per-protocol) in high-risk patients, achieved by a majority of operators new to this technology.
Major Points
- ROADSTER 2 is a prospective, open-label, single-arm, multicenter post-approval registry
- 692 patients enrolled at 43 sites; 632 in per-protocol analysis
- 81.2% of operators were TCAR naïve before study initiation
- 26% had neurological symptoms; all patients had high-risk factors for CEA
- Technical success: 99.7% in both ITT and per-protocol populations
- Per-protocol outcomes: 0.6% stroke, 0.2% death, 0.9% MI
- ITT outcomes: 1.9% stroke, 0.4% death, 0.9% MI
- Composite 30-day stroke/death rate: 0.8% (per-protocol), 2.3% (ITT)
- Procedural success rate: 97.9% (per-protocol), 96.5% (ITT)
- Protocol adherence critical for optimal outcomes
Design
Study Type: Prospective, open-label, single-arm, multicenter, post-approval registry
Randomization:
Blinding: Open-label design
Enrollment Period: 2015 - 2019
Follow-up Duration: 30 days
Centers: 43
Countries: United States, European Union
Sample Size: 632
Analysis: Intention-to-treat (ITT, n=692) and per-protocol (PP, n=632) populations analyzed using descriptive statistics
Inclusion Criteria
- High risk for complications from carotid endarterectomy
- Symptomatic stenosis ≥50% with stroke, TIA, or amaurosis fugax ≤180 days
- Asymptomatic stenosis ≥80% without neurological symptoms ≤180 days
- At least one clinical or anatomic high-risk criteria for CEA
- Age ≥18 years
- Signed informed consent
- At least 5 cm of normal CCA below lesion for safe sheath placement
Exclusion Criteria
- Alternative source of cerebral embolus (atrial fibrillation, heart valve)
- Intracranial hemorrhage within 12 months
- Evolving stroke or severe dementia
- Major cardiovascular surgery within 30 days
- Myocardial infarction within 72 hours
- Carotid thrombus, occlusion, or string sign
- Inflow disease or previous intervention in proximal ipsilateral carotid
- Severe disease in common carotid artery
- Entry site <5 cm to bifurcation
- Open neck stoma
Baseline Characteristics
| Characteristic | Control | Active |
|---|---|---|
| Total ITT Population | 692 patients | |
| Total Per-Protocol | 632 patients | |
| Male | 67.8% (ITT), 67.7% (PP) | |
| Age ≥80 | 21.1% (ITT), 21.2% (PP) | |
| Hypertension | 90.8% (ITT), 90.3% (PP) | |
| Hyperlipidemia | 86.3% (ITT), 85.8% (PP) | |
| Diabetes | 36.0% (ITT), 35.0% (PP) | |
| Smoking History | 77.7% (ITT), 77.8% (PP) | |
| Previous MI | 20.8% (ITT), 20.6% (PP) | |
| Neurological Symptoms | 26.0% (ITT), 26.3% (PP) | |
| TIA/Stroke | 16.0% (ITT), 16.1% (PP) | |
| Age >75 years | 42.1% (ITT), 41.8% (PP) | |
| Anatomic Risk Factors Only | 43.6% (ITT), 43.5% (PP) | |
| Physiologic Risk Factors Only | 31.8% (ITT), 31.8% (PP) | |
| Both Risk Factors | 24.6% (ITT), 24.7% (PP) |
Arms
| Field | TCAR with ENROUTE System |
|---|---|
| Intervention | Transcarotid artery revascularization using ENROUTE Transcarotid Stent and Neuroprotection System with reversal of flow cerebral protection |
| Duration | Single procedure with 30-day follow-up |
Outcomes
| Outcome | Type | Control | Intervention | HR / OR / RR | P-value |
|---|---|---|---|---|---|
| Procedural success (technical success plus absence of stroke, MI, or death within 30 days) | Primary | 97.9% (PP), 96.5% (ITT) | |||
| Technical success | Secondary | 99.7% (both ITT and PP) | |||
| Stroke at 30 days | Secondary | 0.6% (PP), 1.9% (ITT) | |||
| Death at 30 days | Secondary | 0.2% (PP), 0.4% (ITT) | |||
| Myocardial infarction at 30 days | Secondary | 0.9% (both PP and ITT) | |||
| Composite stroke/death | Secondary | 0.8% (PP), 2.3% (ITT) | |||
| Composite stroke/death/MI | Secondary | 1.7% (PP), 3.2% (ITT) | |||
| Cranial nerve injury | Adverse | 1.3% (PP), 1.4% (ITT) |
Subgroup Analysis
Symptomatic patients (PP): 0.6% stroke, 0% death, 0.6% MI. Asymptomatic patients (PP): 0.6% stroke, 0.2% death, 1.1% MI. Protocol adherence crucial for optimal outcomes.
Criticisms
- Single-arm design without randomized control group
- 60 patients had major protocol violations (medication non-compliance)
- Only early 30-day outcomes reported
- Learning curve effects possible despite training
- Selection bias inherent in registry design
- No direct comparison to CEA in same time period
- Majority of operators were TCAR naïve, limiting generalizability
Funding
Post-approval study was a condition of FDA approval for ENROUTE Stent
Based on: ROADSTER 2 Early Outcomes (Stroke, 2020)
Authors: Vikram S. Kashyap, Peter A. Schneider, Mazin Foteh, ..., Timothy Oskin
Citation: Stroke. 2020;51:2620–2629
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