Initial experience with the antithrombogenic-coated CARESTO stent for acute symptomatic cervical internal carotid artery dissections: multicenter study

Abstract

Objectives

To evaluate the technical feasibility, safety, and short-term to mid-term efficacy of the antithrombogenic-coated CARESTO stent in the endovascular treatment of acute symptomatic cervical internal carotid artery dissections (CICAD) with hemodynamically relevant stenosis and disabling neurological deficits.

Methods

This retrospective multicenter study evaluated patients with acute symptomatic CICAD who underwent endovascular treatment with the CARESTO stent. Clinical endpoints included changes in the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (mRS) scores. Imaging endpoints assessed vessel patency, arterial diameter improvement, and revascularization success, defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2b. Safety was evaluated by documenting periprocedural complications.

Results

Between January 2023 and May 2025, 31 patients were treated across six participating neurovascular centers. The mean age was 52.3±10.2 years; 54.8% were female. Stent deployment was successful in all cases. In those with intracranial vessel occlusion (n=22), recanalization was achieved in all patients (mTICI 3: 61.3%; mTICI 2c: 22.6%; mTICI 2b: 16.1%). ICA diameter improved from 1.0±0.5 mm to 4.6±0.6 mm. Median NIHSS score decreased from 11 (IQR 8–14.5) to 1 (IQR 1–3) at 3 months; mRS≤2 was achieved in 83.9%. All stents remained patent, with no major complications or deaths.

Conclusion

This initial multicenter experience suggests that the CARESTO stent is technically feasible and may offer a safe and effective treatment option for acute CICAD. These findings support further prospective evaluation in larger cohorts.

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Symptomatic dissections of the internal carotid artery (ICA) can lead to disabling ischemic stroke, especially when accompanied by hemodynamic compromise. In select patients, endovascular stent reconstruction is an established rescue treatment. However, clinical data on the use of antithrombogenic coated stents in the setting of acute ICA dissections are scarce.

WHAT THIS STUDY ADDS

• This study presents multicenter data on the initial experience with the antithrombogenic-coated CARESTO stent in the treatment of acute ICA dissections. The findings demonstrate excellent technical success, favorable clinical outcomes, and an absence of periprocedural or delayed complications.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• These results support the CARESTO stent as a safe and effective option in selected patients with acute ICA dissections. The study encourages further research into coated stents in dissection treatment and may inform future recommendations for endovascular management in this high-risk subgroup.

Introduction

Cervical internal carotid artery dissection (CICAD) is defined by a tear in the intimal layer of the vessel wall, leading to the formation of an intramural hematoma (IMH) and separation of the arterial wall layers. The most serious complication of CICAD is ischemic stroke, affecting many patients and often causing long-term disability, with considerable morbidity and mortality.^1–3

There are various therapeutic strategies for the management of ICAD, all aiming to prevent ischemic complications. Medical treatment—including anticoagulation therapy (ACT) and antiplatelet therapy (APT) regimens—has been extensively studied and is commonly used in patients with acute CICAD. Several studies have reported no significant difference in outcomes between ACT and APT in this setting.⁴ However, invasive treatment may be required in patients with persistent ischemia despite medical treatment, contraindications to anticoagulation, iatrogenic dissections, or critically reduced cerebral perfusion.^5–7 Endovascular stenting is an effective option for these selected patients with CICAD, especially with hemodynamic compromise, progressive internal carotid artery (ICA) stenosis, or worsening symptoms, showing high technical success, good outcomes, and low complication rates.^{8 9}

A major challenge in CICAD management is the safe and effective treatment of lesions extending toward the skull base, particularly when the distal landing zone is located within the petrous ICA. Conventional carotid stents, optimized for atherosclerotic disease, are often too rigid for navigating tortuous distal anatomy and may not allow precise deployment in this location. In contrast, more flexible options—such as braided intracranial stents, flow diverters, or self-expanding laser-cut stents—offer superior navigability but often lack the radial strength or length required to achieve durable vessel reconstruction.

The CARESTO stent is a new hybrid vascular implant that combines the radial strength of conventional carotid stents with the flexibility and deliverability of braided intracranial designs. Its low-profile delivery system enables navigation through tortuous dissections and precise placement from the petrous ICA to the extracranial segment. Available in longer lengths than comparable devices, it also features an antithrombogenic fibrin/heparin coating designed to reduce thromboembolic risk in the acute setting.¹⁰

To our knowledge, this is the first clinical study to report the use of this stent design for acute symptomatic CICAD. Addressing significant anatomical and technical challenges, we aimed to assess the technical feasibility, safety, and short-term to mid-term efficacy of the antithrombogenic-coated CARESTO stent in patients with hemodynamically relevant stenosis and disabling neurological deficits. This multicenter series offers real-world evidence on a novel device concept tailored to a challenging anatomical subset of CICAD.

Methods

Study design

This was a retrospective multicenter study. Ethical approval was obtained from the central ethics committee of the coordinating institution (Philipps University Marburg; IRB number 24–180 RS), which waived the requirement for individual patient consent due to the retrospective design and the use of fully anonymized data. Because of the retrospective and anonymized nature of the data, no additional IRB approvals were required at the collaborating centers. All data were collected and analyzed in a fully anonymized manner in compliance with institutional and national data protection regulations.

Study participants

Patients were eligible for inclusion if they had a confirmed diagnosis of CICAD based on clinical presentation and radiological findings. Typical clinical signs suggestive of CICAD included local symptoms such as headache, neck pain, and/or Horner’s syndrome, as well as ischemic symptoms such as hemiparesis, hemihypesthesia, ataxia, aphasia, dysarthria, visual disturbances, or neglect. Only patients presenting with a National Institutes of Health Stroke Scale (NIHSS) score ≥ 5 were included. Both spontaneous and traumatic dissections were eligible, without differentiation between etiologies for the purpose of this study. Radiological confirmation of dissection was required and had to be demonstrated by at least one imaging modality, including MRI, CT angiography (CTA), or DSA. No patients were excluded from the study for other reasons.

Endovascular procedures

All procedures were performed under general anesthesia using a biplane angiographic system. Vascular access was obtained via an 8 French short femoral sheath. A biaxial or triaxial access system was advanced under fluoroscopic guidance, depending on individual anatomical and procedural requirements. In cases of intracranial or cervical vessel occlusion, mechanical thrombectomy was initially performed using aspiration and/or a stent retriever. This was followed by implantation of the CARESTO stent along the dissected segment of the ICA. The stent was delivered through the recommended NeuroSlider 0.052 inch delivery catheter (Acandis). In cases of residual ICA stenosis after stent deployment, percutaneous transluminal angioplasty (PTA) was performed using a dedicated PTA balloon catheter (figures 1–3).

Figure 1. DSA demonstrating a dissection of the right internal carotid artery (ICA) at its typical location near the skull base (C1–C2 segments), before and after endovascular treatment using the CARESTO stent. 1—Cervical segment of the ICA. 2—Petrous segment of the ICA. 3—Intramural hematoma. 4—High-grade ICA stenosis due to dissection. 5—Pseudoaneurysm of the ICA. 6—CARESTO stent. 7—Long sheath. 8—Percutaneous transluminal angioplasty (PTA) balloon. 9—Microwire. 10—Reconstructed vessel segment after treatment. (A) Pre-treatment angiogram showing a dissection with a resulting high-grade flow-limiting stenosis of the ICA. (B) Unsubtracted angiogram showing the CARESTO stent in place, with a PTA balloon deployed within the stent to optimize luminal restoration. (C) Post-treatment angiogram demonstrating successful reconstruction of the dissected ICA segment with restored vessel patency and complete resolution of the stenosis.

Figure 3. Representative images of a 6×50 mm antithrombogenic-coated CARESTO stent, illustrating its hybrid design, high flexibility, and suitability for reconstructing dissections in tortuous anatomy.

Figure 2. DSA illustrating cerebral perfusion in the setting of a right internal carotid artery (ICA) dissection at its typical location near the skull base (C1–C2 segments), before and after endovascular treatment with the CARESTO stent. 1—ICA. 2—Internal maxillary artery. 3—Superficial temporal artery. 4—Occipital artery. 5—Middle cerebral artery (MCA). 6—Anterior cerebral artery (ACA). (A) Pre-treatment angiogram showing markedly reduced cerebral perfusion due to ICA dissection, with delayed and diminished filling of intracranial arteries, while branches of the external carotid artery (ECA) demonstrate rapid opacification extending into the peripheral circulation. (B) Post-treatment angiogram demonstrating successful re-establishment of anterograde flow through the ICA and normalization of perfusion to the MCA and ACA territories.

Antithrombogenic regimen

At the beginning of the procedure, all patients received an intravenous bolus of 4000 IU of heparin. In cases where intravenous thrombolysis (IVT) was administered, heparin was omitted. Prior to stent deployment, an intravenous loading dose of 500 mg acetylsalicylic acid (ASA) was administered in all cases. Two hours after the intervention, a multimodal CT protocol—including CTA and CT perfusion imaging—was performed to rule out hemorrhagic or thrombotic complications. Subsequently, a loading dose of 300 mg clopidogrel was administered. Starting on the following day, dual antiplatelet therapy (DAPT) with 100 mg ASA and 75 mg clopidogrel once daily was continued for a period of 3 months. Platelet inhibition was monitored using the VerifyNow system (Werfen), and the antiplatelet regimen was adjusted accordingly if necessary. After the DAPT period, patients were switched to ASA 100 mg once daily, which was continued as lifelong secondary prevention.

Clinical endpoints

Clinical outcomes were evaluated based on changes in the modified Rankin Scale (mRS), assessed at discharge and at the 3-month follow-up. Additionally, National Institutes of Health Stroke Scale (NIHSS) scores were recorded at admission, at discharge, and at 3 months to assess neurological improvement. Procedural safety was assessed by documenting any procedure-related complications, including in-stent thrombosis, restenosis, vessel perforation, air embolism, hemorrhagic events, secondary dissections, and vessel occlusions.

Imaging endpoints

Imaging endpoints were assessed based on the degree of revascularization success. In cases of CICAD presenting with vessel occlusion (VO), successful recanalization was defined as achieving a modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2b. In patients with isolated stenosis due to CICAD, recanalization success was evaluated by assessing the improvement in stenosis diameter and comparing the post-interventional blood flow in the ICA to that of the external carotid artery (ECA). A residual stenosis of less than 50% was considered indicative of successful recanalization.

$${\displaystyle {\displaystyle \mathrm{\%}stenosis=\left[1-\frac{diameterofstenosis}{diameterofnormalparentvessel}\right]\times 100}}$$

All patients underwent standardized early post-procedural imaging to assess stent patency and exclude procedure-related complications. This included non-contrast CT and CTA at 2 hours and 48 hours after the intervention. At 3 months, follow-up vascular imaging was performed in all patients using CTA and duplex sonography. Imaging assessments focused on vessel patency, presence of in-stent stenosis, and detection of thrombotic or other adverse events.

Data collection

Demographic, clinical, imaging, procedural, and follow-up data were retrospectively collected and managed in Microsoft Excel. Procedural information, including materials, techniques, and complications, was systematically documented. Follow-up imaging was evaluated via the institutional PACS. Data integrity was ensured through standardized documentation and cross-validation.

Data analysis

Continuous variables were reported as mean±SD or median with interquartile range (IQR), depending on distribution. Categorical variables were summarized as counts and percentages. Group comparisons used t-tests or Mann–Whitney U tests for continuous variables, and χ² or Fisher’s exact tests for categorical variables. Functional outcomes (e.g., mRS) were analyzed using the Wilcoxon signed-rank test. Paired t-tests assessed changes in continuous measures over time, with mean differences and 95% confidence intervals reported. Statistical significance was set at P value <0.05. Analyses were based on complete case data and performed using Jamovi version 27.0 (IBM Corp., Armonk, NY, USA).

Results

Demographic, clinical, and imaging characteristics

Between January 1, 2023, and May 8, 2025, 31 patients with acute symptomatic CICAD were treated with the CARESTO stent across six participating neurovascular centers and were included in the analysis. The mean age was 52.3±10.2 years (range 26–72 years), with (17/31, 54.8%) female. Dissections most frequently involved the C1 segment only (n=17), followed by combined C1–C2 involvement (n=11) and isolated C2 dissections (n=3). Left-sided dissections were observed in 19 patients (61.3%). None of the patients received APT or ACT prior to the procedure. IVT was administered in 22 cases (71%) due to associated intracranial VO. The median NIHSS score at admission was 11 (8–14.5), and the median pre-intervention ASPECT (Alberta Stroke Program Early CT) score was 9 (9–10) (table 1).

Table 1. Demographic, clinical, and imaging characteristics.

Parameters	N (%) or mean±SD or median (IQR)
Age	52.3±10.2
Gender, female	17 (54.8)
CICAD laterality left	19 (61.3)
ICA occlusion	4 (12.9)
Intracranial VO	22 (71)
IVT administered	22 (71)
Intracranial VO location
MCA
M1	13 (41.9)
M2	7 (29)
M3	0 (0)
ACA	0 (0)
APT	0 (0)
ACT	0 (0)
Admission NIHSS	11 (8–14.5)
Pre-intervention ASPECT score	9 (9–10)

ACA, anterior cerebral artery; ACT, anticoagulation therapy; APT, antiplatelet therapy; ASPECT, Alberta Stroke Program Early CT; CICAD, cervical internal carotid artery dissection; ICA, internal carotid artery; IVT, intravenous thrombolysis; MCA, middle cerebral artery; NIHSS, National Institutes of Health Stroke Scale; VO, vessel occlusion.

Clinical endpoints

The median NIHSS score improved significantly from 11 (8–14.5) at admission to 4 (2–6) post-intervention, and further to 1 (1–3) at the 3-month follow-up, indicating substantial neurological recovery. Functional outcome as measured by the mRS scale showed a median score of 3 (2–3) at discharge and improved to 1 (0–2) at 3 months. A favorable functional outcome (mRS≤2) was achieved in 26 of 31 patients (83.9%). No patient experienced clinical deterioration, and no mortality occurred during the observation period (table 2).

Table 2. Clinical, imaging, and procedural endpoints.

Parameters	N (%) or mean±SD or median (IQR)
Post-intervention NIHSS	4 (2–6)
3-month NIHSS	1 (1–3)
Discharge mRS	3 (2–3)
3-month mRS	1 (0–2)
3-months mRS≤2	26 (83.9)
mTICI score
mTICI 3	19 (61.3)
mTICI 2c	7 (22.6)
mTICI 2b	5 (16.1)
Mean normal ICA diameter (mm)	5±0.6
Mean deployed stent diameter (mm)	6.9±1.1
Mean deployed stent length (mm)	44.8±8.5
Mean pre-interventional luminal diameter at dissection (mm)	1.0±0.5
Mean post-interventional luminal diameter at dissection (mm)	4.6±0.6
Post-intervention ASPECT score	8 (7–9)

ASPECT, Alberta Stroke Program Early CT; ICA, internal carotid artery; mRS, modified Rankin Scale; mTICI, modified Thrombolysis in Cerebral Infarction; NIHSS, National Institutes of Health Stroke Scale.

Imaging endpoints

In patients with intracranial VO (n = 22), successful recanalization was achieved in all cases, with a mTICI 3 score in 19 patients (61.3%), mTICI 2c in 7 patients (22.6%), and mTICI 2b in 5 patients (16.1%). Among patients with isolated stenosis due to CICAD, revascularization was successful (residual stenosis <50% and no relevant flow delay in the ICA compared with the ECA) in all cases. The median ASPECT score prior to intervention was 9 (9–10) and decreased only slightly to 8 (7–9) after intervention, indicating limited infarct progression. All treated vessels demonstrated sustained patency on follow-up imaging (table 2).

The mean normal diameter of the ICA—measured distal to the dissected segment—was 5±0.6 mm. This diameter guided the stent selection to ensure optimal vessel reconstruction. The mean deployed stent diameter was 6.9± 1.1 mm, and the mean stent length was 44.8±8.5 mm, chosen to fully cover the dissected segment and ensure stable anchoring in healthy vessel segments proximal and distal to the dissection. A marked restoration of luminal diameter was observed following endovascular treatment. Within the dissection, the mean luminal diameter prior to treatment was significantly reduced to 1.0±0.5 mm, indicating substantial flow-limiting stenosis. Following stent implantation, the luminal diameter within the dissected segment increased significantly to 4.6±0.6 mm (P-value<0.0001), demonstrating effective mechanical re-expansion and restoration of vessel patency (table 2). These findings support the efficacy of the CARESTO stent in resolving the hemodynamic impact of acute CICAD.

At 2 hours and 48 hours after the procedure, CTA demonstrated 100% patency of all treated ICA segments (n=31) without in-stent thrombosis, relevant residual stenosis (<50%), or new dissections. At 3 months, CTA and duplex sonography again confirmed 100% patency, with no cases of clinically relevant in-stent restenosis, stent occlusion, or thromboembolic events. Vessel reconstruction remained stable in all patients throughout the follow-up period. No longer-term imaging follow-up beyond 3 months was available for evaluation.

Procedural safety

No major periprocedural complications occurred. Specifically, there were no instances of in-stent thrombosis, relevant restenosis, vessel perforation, air embolism, secondary dissection, or hemorrhagic events. All treated vessels remained patent throughout follow-up, and no hemodynamically significant in-stent stenosis or thrombotic events were detected. The intervention was well tolerated, demonstrating a consistently favorable safety profile across all participating centers.

Onset-to-revascularization time

The median onset-to-revascularization time for the entire cohort was 210 min (IQR 180–240 min). Patients with intracranial VO (n=22) had a slightly longer median time compared with those without occlusion (220 min (IQR 190–250) vs 190 min (IQR 170–210)). The shortest recorded time was 110 min and the longest 420 min, with the latter observed in a patient transferred from a referring hospital. These data are summarized in table 3.

Table 3. Onset-to-revascularization time.

Parameter	All patients (n=31)	With intracranial VO (n=22)	Without intracranial VO (n=9)
Median (IQR) onset-to-revascularization time (min)	210 (180–240)	220 (190–250)	190 (170–210)
Minimum	110	120	110
Maximum	420	420	260

VO, vessel occlusion.

Discussion

This multicenter retrospective study suggests that endovascular treatment of acute symptomatic CICAD using the antithrombogenic-coated CARESTO stent is technically feasible and appears to be associated with favorable short-term and mid-term clinical outcomes. In this series, patients showed neurological improvement and sustained vessel patency, and no major periprocedural complications were observed. Notably, there were no cases of in-stent thrombosis, clinically relevant restenosis, or hemorrhagic events during the follow-up period. These findings may reflect a potential benefit of the stent’s antithrombogenic coating. However, further prospective large cohort studies are needed to confirm these observations and evaluate long-term outcomes.

Stent deployment was technically successful in all cases, with favorable angiographic outcomes reflected by mTICI scores ≥2b in every patient with intracranial occlusion. In patients with isolated dissection-related stenosis, residual stenosis was consistently <50%, with no flow delay relative to the ECA. Importantly, imaging follow-up demonstrated stable vessel patency without restenosis or reocclusion, confirming the durability of the intervention. From a clinical perspective, the improvement in NIHSS and mRS scores across all patients highlights the potential of early mechanical reconstruction in appropriately selected cases. The majority of patients (83.9%) achieved functional independence (mRS≤2) at 3 months.

While conservative medical treatment remains the first-line approach in most cases of CICAD, our study addresses a subgroup of patients with disabling symptoms and clear perfusion deficits, where urgent revascularization is necessary to prevent infarct progression. In these selected patients, reconstructive stenting offers the advantage of immediate vessel reconstruction and restoration of cerebral blood flow.^5–7

The role of the CARESTO stent has not previously been studied specifically for CICAD. Our results align with and expand on prior findings regarding the safety and efficacy of endovascular treatment for cervical ICA dissections using other uncoated stent systems. In a systematic review by Hoving and colleagues, which included several uncoated stent systems (Carotid Wallstent, Enterprise, Wingspan, Acculink, and Leo), endovascular treatment in patients with cervical dissection and concurrent intracranial vessel occlusion demonstrated high rates of successful recanalization (84%) and favorable functional outcomes (mRS≤2 in 68% of patients), but also a complication rate of approximately 12%, including in-stent thrombosis and hemorrhage.⁹ In contrast, our cohort treated with the CARESTO stent showed a 100% technical success rate, a higher rate of favorable functional outcome (mRS≤2 in 83.9%), and no observed periprocedural complications or thromboembolic events. While the differences may partially reflect patient selection and sample size, they also suggest a potential benefit of the antithrombogenic surface coating, which may have contributed to the absence of thrombotic complications in our series. This observation underscores the need for further studies comparing coated and uncoated stents in the setting of acute dissections with hemodynamic impairment.

Limitations

This study has several limitations. Its retrospective design and small sample size limit generalizability and statistical power. The lack of a control group prevents direct comparison with other treatments. Follow-up was restricted to short-term and mid-term outcomes, so long-term durability and delayed complications remain unclear. Finally, multicenter variability in technique and patient selection may have influenced outcomes. Future prospective studies with larger cohorts are needed to validate these findings and better define the specific indications—particularly in terms of stenosis severity and hemodynamic relevance—for endovascular stenting as a potential first-line treatment option in acute CICAD.

Conclusion

This initial multicenter experience suggests that endovascular treatment of acute symptomatic CICAD using the antithrombogenic-coated CARESTO stent is technically feasible and appears to offer a favorable safety and efficacy profile in the short to mid term. No major procedural complications were observed, and most patients showed substantial neurological improvement with sustained vessel patency. However, these findings should be interpreted with caution due to the retrospective design and limited sample size. Larger prospective studies are warranted to validate these results and further define the role of the CARESTO stent in the acute management of CICAD.

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.