Objective
To compare the performance of the RoadsaverTM (RS) dual-layer micromesh stent (Terumo) vs. Carotid Wallstent (CW) single-layer stent (Boston Scientific) with proximal (Mo.MaTM, Medtronic) or distal embolic protection (Filterwire EZTM (FW), Boston Scientific) in carotid stenosis patients with high-risk (lipid-rich) plaques.
Study Group
- Single-center, prospective, randomized study
- Enrolment from 2016 - 2018
- 219 consecutive patients with unilateral de novo carotid artery stenosis
- symptomatic (Doppler peak systolic velocity [PSV] ≥130 cm/s and >50% stenosis)
- asymptomatic (Doppler [PSV] ≥ 230 cm/s and >70% stenosis)
- If optimal, patients were randomly assigned to 4 groups receiving
- FW + RS (group 1)
- FW + CW (group 2)
- Mo.Ma + RS (group 3)
- Mo.Ma + CW (group 4)
- Primary end-point
- Number of microembolic signals (MES) measured by Transcranial Doppler (TCD) ultrasound
- Secondary end-points
- In-hospital and 30-day MACCE (major adverse cardiac and cerebrovascular events; i.e. death, all stroke, myocardial infarction)
- Technical and clinical success
- Acute ECA angiographic patency after CAS
- Acute and long-term (24 h, 30-days, 6-month F/U) ECA patency and In-Stent Restenosis (ISR) rate by Doppler US at 6 months.
Methods
- The institutional protocol for CAS was used in all patients.
- Co medication:
- All patients were treated with aspirin 100 mg/day plus clopidogrel 75 mg/day for at least 10 days before CAS and 1 month afterward.
- During CAS, patients received unfractionated intravenous heparin (5,000 IU) to reach an activated clotting time >250 s.
- In all patients, neurological examinations were conducted by a neurologist before, during, and after CAS and at 30 days
- Doppler examination was performed on EPIQ 5 ultrasound system by 4 experienced sonographers (>2,000 examinations/ year) for both target and contralateral internal carotid artery (ICA) and ECA.
- Measurements were repeated at 24 h, 30 days, and 6 months post-CAS.
- Significant In-Stent Restenosis (ISR) was defined as PSV >330 cm/s with >80% diameter stenosis.
- Carotid stenosis severity and composition were assessed using magnified cross-sectional computed tomographic images obtained at the most severe narrowing site.
- TCD assessment
- Two 2 X 2 MHz probes connected to TCD equipment (Digi-Lite, Raanana, Israel) were fitted on a headband and placed on the temporal bone window for bilateral continuous measurement of flow velocity in the ipsilateral M1 segment of the middle cerebral artery and contralateral A1 segment of the anterior cerebral artery.
- Assessment of MES was carried out from the ipsilateral middle cerebral artery, whereas flow velocity assessment of the contralateral anterior cerebral artery was used for detecting activation of the collateral pathway via the anterior communicating artery with the Mo.Ma Ultra device.
- Cerebral MES were counted during (and in between) the following CAS steps:
- Target vessel engagement with guide and sheath or Mo.Ma;
- Positioning of guide and sheath or proximal protection;
- Lesion crossing with either the FW or a 0.014-inch coronary wire in the Mo.Ma group after CCA occlusion;
- Lesion pre-dilation;
- Lesion crossing with the stent;
- Stent deployment;
- Stent dilation;
- FW or Mo.Ma system retrieval and deflation.
- Contrast injection during CAS in the distal filter groups increased Doppler signal intensity, leading to a possible uncorrected evaluation of MES. Therefore, these signals were excluded from the final analysis.
- Some Doppler signals could not be counted individually in the specific procedural steps. Thus, 1 s of microembolic shower was considered as 10 MES.
- Macroemboli (emboli that partially or completely obstructed the middle cerebral artery) were also assessed.
Results
- Mo.Ma significantly reduced mean MES count (p < 0.0001) during lesion crossing, stent crossing, stent deployment and post-dilation versus FW.
- RS significantly reduced MES count vs CW (p = 0.016) during the stent deployment, postdilation and EPD retrieval phase (including the spontaneous MES between the subsequent steps).
- The combination of Mo.Ma + RS performed significantly better than Mo.Ma + CW (p = 0.043)
- MACCE: 3 pts (1 retinal embolism & 1 death* at day 25 in RS+FW group vs 1 minore stroke with CW +MoMa) (p = 0.5). *death reported as cardiac shock (due to acute rupture of an iliac aneurysm)
- ISR: 1 pt with CW stent implantation (0.98%) at 6-month follow-up.
- RS was an independent predictor of ECA patency over time.
Conclusion
In patients with high-risk, lipid-rich plaques undergoing CAS, combination of Mo.Ma and RoadsaverTM led to the lowest MES count and RoadsaverTM outperformed the Carotid Wallstent in terms of intra-procedural cerebral protection from the microembolic cerebral ischemic injury. This RCT supports the embolic protective properties of the RoadsaverTM micromesh.
