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ROADSTER 2 Early Outcomes

Early Outcomes in the ROADSTER 2 Study of Transcarotid Artery Revascularization in Patients With Significant Carotid Artery Disease

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Year of Publication: 2020

Authors: Vikram S. Kashyap, Peter A. Schneider, Mazin Foteh, ..., Timothy Oskin

Journal: Stroke

Citation: Stroke. 2020;51:2620–2629

Link: https://doi.org/10.1161/STROKEAHA.120.030550

PDF: https://www.ahajournals.org/doi/epub/10....EAHA.120.030550

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?

Study Overview

Objective

Early outcomes of transcarotid artery revascularization (TCAR) performed by physicians with variable experience.

Study Summary

ROADSTER 2 demonstrated excellent 30-day outcomes with 0.6% stroke rate and 0.2% death rate in per-protocol population of 632 high-risk patients.
Technical success achieved in 99.7% of cases despite 81.2% of operators being TCAR naïve.

Intervention

ENROUTE Transcarotid Stent and Neuroprotection System with reversal of flow cerebral protection vs. historical controls.

Patients per Arm

632 patients in per-protocol analysis (692 total intention-to-treat)

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 (ITT) at 43 sites; 632 in per-protocol analysis after excluding 60 patients with major protocol deviations
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: 692

Analysis: Intention-to-treat (ITT, n=692 enrolled) 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, other cardiac/cerebral sources)
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/brachiocephalic artery
Severe disease in common carotid artery; entry site <5 cm to bifurcation
Isolated hemisphere
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	Intervention
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 (72 total deviations): 11 did not meet inclusion/exclusion criteria and 48 were not on dual antiplatelets plus statin therapy peri-procedurally, with additional study-medication timing deviations
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

Sources of Funding: None (per paper). Conduct of the ROADSTER 2 post-approval study was a condition of FDA approval for the ENROUTE Stent (Silk Road Medical, Inc); several authors report consulting, proctoring, or research relationships with Silk Road Medical.

Based on: ROADSTER 2 Early Outcomes (Stroke, 2020)