Long-term outcomes of the micronet-covered stent system routine use for carotid revsacularization in stroke prevention: PARADIGM-Extend 5 year evidence

Abstract

Background Diffusion-weighted magnetic resonance imaging indicates that micronet-covered embolic prevention stent system effectively minimizes peri-procedural and prevents lesion-related post-procedural cerebral embolism in carotid artery stenting but long-term clinical evidence is missing. Purpose To provide long-term clinical and duplex ultrasound evaluation of safety and efficacy of the system use in consecutive carotid revascularization patients. Methods PARADIGM-EXTEND is in all-comer, all-referrals-tracked study with no exclusion criteria other than lack of NeuroVascular Team-determined indication. Clinically asymptomatic patients receive revascularization only in case of increased-stroke-risk characteristics. Adverse events are independently adjudicated. Results Currently 451 patients (48–87 years, 59% symptomatic, 127 women) with 490 arteries crossed the first follow-up window of 30 days. There has been 100% micronet-covered embolic prevention stent system use (ie, no other stent type/s used throughout study). Proximal/distal intra-procedural neuroprotection use was 38.3%/61.7%. Large balloon/high-pressure stent optimization was routine, leading to a single-digit (mean 6.9%) residual diameter stenosis. Independent neurologist and duplex evaluation are before and after revascularization (48h and 30 days, then yearly). Peri-procedural death or major ischemic stroke rate was 0%. One event (prior infarct scar asymptomatic extension in prolonged hypotension course) was adjudicated as minor stroke (0.22%), and there was 1 periprocedural MI (type 2, in 2-vessel non-revascularizable CTO; 0.22%). By 30 days there were no further ischaemic strokes (0%) but there was 1 haemorrhagic transformation that led to death (0.22%) and 1 bleeding-related death (0.22%). Thus total 30-day death/stroke was 0.66%, and total death/stroke/MI was 0.88%. By 60 months there were 3 contralateral, 1 ipsilateral (device-unrelated), and 2 posterior circulation strokes. Baseline internal carotid artery velocities were 3.72±1.25 and 0.63±0.69 m/s (peak-systolic and end-diastolic). Post-procedural in-stent velocities were normal and remained normal throughout the 60-month follow-up period: 0.78±040 and 0.21±0.10 (1y); 0.75±0.36 0.19±0.09 (2y); 0.75±0,35 and 0.21±0.09 (3y); 0.72±0.27 and 0.20±0.07 (4y); 0.79±0.58 and 0.21±0.11m/s (5y). There were 2 in-stent restenoses by 1y (including 1 that occurred with de novo neck radiotherapy) and 1 other by 2y (total 2y in-stent restenosis of 1.1%) but no further ones (0% in-stent restenosis at 2–5y). Conclusions PARADIGM-Extend long-term clinical and duplex ultrasound evidence is consistent with normal healing and sustained safety and stroke prevention efficacy of the micronet-covered embolic prevention stent system used routinely, on top of optimized medical therapy, for stroke prevention in symptomatic and increased-stroke-risk asymptomatic subjects with carotid stenosis recommended for revasularization by the NeuroVascular Team. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Jagiellonian University Medical College

Clinical Outcomes of Second- versus First-Generation Carotid Stents: A Systematic Review and Meta-Analysis

“…What is needed next is (i) to rigorously compare SGS outcomes against contemporary surgery and the hybrid carotid revascularization technique of transcarotid revascularization (TCAR) using a conventional (single-layer) carotid stent and (ii) to evaluate long-term outcomes with SGSs [ 178 ]. SGS comparisons against contemporary carotid endarterectomy that shows a 30-day DSM of ≈1.9% [ 233 ] is particularly needed.…”

“…This suggests that SGS plaque sealing might improve TCAR outcomes in symptomatic patients and high-risk lesions in particular [ 235 ]. Rigorous follow-up of SGS-implanted patients beyond 12 months is also needed [ 178 , 229 , 236 ].…”

Diabetes Mellitus and Clinical Outcomes in Carotid Artery Revascularization Using Second-Generation, MicroNet-Covered Stents: Analysis from the PARADIGM Study

“…Recent data suggest that a proportion of "in-stent restenoses" in single-layer (conventional) stents may represent plaque progression into the lumen [12]; an adverse phenomenon is amenable to elimination with MCS [11,12]. This is important because "in-stent restenosis" is associated with an increased risk of recurrent stroke [24,25], and it poses a significant management challenge [12,37,38]. EDV (m/s ± SD) 0:22 ± 0:18 0:21 ± 0:09 0.74 RICA: right internal carotid artery; QCA: quantitative comparative analysis; PSV: peak systolic velocity; EDV: end diastolic velocity; EPD: embolic protection device.…”

“…This risk is not amenable to any sufficient control with classic optimized medical therapy (high-dose statin titrated to achieve guideline-indicated LDL-cholesterol level, antiplatelet agent, ACEI/ARB) [ 13 ], and it is also not reduced with gliflozines [ 24 ]. Thus, procedural low-risk carotid revascularization with plaque sealing [ 11 ] (on top of maximized medical therapy) might play an important role in durable stroke risk reduction [ 25 ] in diabetic patients with increased stroke-risk carotid stenosis. An important aspect of diabetes in the context of conventional cardiovascular interventions is that DM is associated with a permanent prothrombotic state that may importantly enhance the risk of stent thrombosis and restenosis [ 26 ].…”

“…Recent data suggest that a proportion of “in-stent restenoses” in single-layer (conventional) stents may represent plaque progression into the lumen [ 12 ]; an adverse phenomenon is amenable to elimination with MCS [ 11 , 12 ]. This is important because “in-stent restenosis” is associated with an increased risk of recurrent stroke [ 24 , 25 ], and it poses a significant management challenge [ 12 , 37 , 38 ].…”