Radial access for peripheral vascular intervention: the S.M.A.R.T. RADIANZ Vascular Stent System.

INTRODUCTION: Radial access is the standard of care for nearly all cardiac catheterization procedures. It improves patient satisfaction, reduces the length of stay, and is associated with fewer complications. However, few devices and tools are available for the treatment of peripheral arterial disease via a transradial approach (TRA). The S.M.A.R.T. RADIANZ Vascular Stent System is among the RADIANZ suite of products, which is aimed at expanding the portfolio of devices to treat peripheral arterial disease. AREAS COVERED: In this Expert review, the following areas will be covered: (1) Current Landscape of peripheral vascular intervention (PVI) using TRA (2) Detailed description of the S.M.A.R.T. RADIANZ Vascular Stent System. (3) Ongoing clinical trials to evaluate safety of this approach. (4) Future directions and current regulatory status. EXPERT OPINION: TRA for PVI is a promising approach. It holds the possibility of substantially improving the care of patients with peripheral arterial disease (PAD). Numerous challenges must be overcome to realize the full potential of a radial-to-peripheral (RTP) approach. The length of devices and the small sheath size are the main constraints of this approach. The results of the ongoing RADIANCY trial will demonstrate the safety, in selected patients, of the RADIANZ suite of products.

Endovascular stroke therapy outside core working hours in a nationwide stroke system.

BACKGROUND: Endovascular therapy (EVT) has been established as a major component in the acute treatment of large vessel occlusion stroke. However, it is unclear whether outcome and other treatment-related factors differ if patients are treated within or outside core working hours. METHODS: We analyzed data from the prospective nationwide Austrian Stroke Unit Registry capturing all consecutive stroke patients treated with EVT between 2016 and 2020. Patients were trichotomized according to the time of groin puncture into treatment within regular working hours (08:00-13:59), afternoon/evening (14:00-21:59) and night-time (22:00-07:59). Additionally, we analyzed 12 EVT treatment windows with equal patient numbers. Main outcome variables included favorable outcome (modified Rankin Scale scores of 0-2) 3 months post-stroke as well as procedural time metrics, recanalization status and complications. RESULTS: We analyzed 2916 patients (median age 74 years, 50.7% female) who underwent EVT. Patients treated within core working hours more frequently had a favorable outcome (42.6% vs 36.1% treated in the afternoon/evening vs 35.8% treated at night-time; p=0.007). Similar results were found when analyzing 12 treatment windows. All these differences remained significant in multivariable analysis adjusting for outcome-relevant co-factors. Onset-to-recanalization time was considerably longer outside core working hours, which was mainly explained by longer door-to-groin time (p<0.001). There was no difference in the number of passes, recanalization status, groin-to-recanalization time and EVT-related complications. CONCLUSIONS: The findings of delayed intrahospital EVT workflows and worse functional outcomes outside core working hours in this nationwide registry are relevant for optimization of stroke care, and might be applicable to other countries with similar settings.

Single rotation CTA of extracranial carotids integrated with cerebral CTP provides sufficient quality for decision making in patients with ischaemic stroke.

PURPOSE: Large volume computed tomography scanners with 16 cm Z-axis single rotation coverage enable joggle-mode scanning of cerebral computed tomography perfusion and single rotation computed tomography angiography of cervical arteries. Our study aims to evaluate the feasibility of scanning cervical arteries, acquired with single rotation computed tomography angiography during computed tomography perfusion in ischaemic stroke patients. MATERIALS AND METHODS: A total of 143 patients were scanned with a single contrast medium injection of 60 ml. Hounsfield units of the cervical arteries and veins were objectively measured and carotid bifurcations were subjectively reviewed. The incidence of artefacts and supra-aortic vessel coverage was recorded. RESULTS: Single rotation computed tomography angiography of the neck demonstrated supra-aortic vessels to their origins in 58 (40.6%) patients. Ninety-nine per cent (1140/1152) of arterial segments were adequately opacified (≥150 Hounsfield units). Arteries were adequately contrasted compared to veins in 81.3% (915/1126) of segments. However, the opacification was reversed in 14.0% (158/1126) of segments, indicating a delayed timing of acquisition; 95.5% (273/286) of carotid bifurcations were of good image quality. Measurement of internal carotid artery stenosis in single rotation computed tomography angiography according to the North American Symptomatic Carotid Endarterectomy Trial correlated well with digital subtraction angiography (R=0.87, P<0.05). Significant artefacts resulted from metal/dental implants (10.5%), contrast in central veins (7.7%) and the shoulder region (4.9%). CONCLUSION: Single rotation computed tomography angiography of the neck incorporated into cerebral computed tomography perfusion with single contrast medium administration revealed adequate image quality for further decision-making in our patient sample. The main drawbacks were inadequate coverage of supra-aortic arteries and possible delay in timing of the joggle.

Detection of Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage Using Motor Evoked Potentials.

BACKGROUND: Early detection of vasospasm (VS) following aneurysmal subarachnoid hemorrhage (aSAH) is vital to trigger therapy and to prevent infarction and subsequent permanent neurological deficit. Although motor evoked potentials (MEPs) are a well-established method for intraoperative detection of cerebral VS and cerebral ischemia during aneurysm surgery, there are no studies investigating the diagnostic value of MEPs for detecting delayed VS following aSAH in an intensive care unit. OBJECTIVE: A prospective study was conceived to assess the diagnostic accuracy of MEPs in comparison with digital subtraction angiography. METHODS: MEP threshold changes were determined in patients both with and without angiographic VS following high-grade aSAHs. Sensitivity, specificity, and the positive and negative predictive values of significant MEP threshold increases, which indicate angiographic VS, were calculated. RESULTS: In all patients experiencing VS of the arteries supplying cerebral motor areas, a minimal MEP threshold increase of 50 mA (mean 66.25 mA) was observed, whereas a maximum MEP threshold increase of 30 mA was observed in patients without VS. Therefore, an increase from a baseline of ≥50 mA was considered significant and resulted in a sensitivity of 0.83, a specificity of 0.92, a positive predictive value of 0.83, and a negative predictive value of 0.92. CONCLUSION: VS following aSAH can be detected accurately by using MEPs. MEPs are a feasible bedside tool for online VS detection in an intensive care unit and, therefore, may complement existing diagnostic tools.

Sustained benefit at 2 years for covered stents versus bare-metal stents in long SFA lesions: the VIASTAR trial.

PURPOSE: The hypothesis that covered stents are superior to bare-metal stents (BMS) in long femoropopliteal artery disease was tested. The one-year results of the VIASTAR trial revealed a patency benefit of covered stents in the treatment-per-protocol (TPP) analysis only. METHODS: A prospective, randomized, single-blind, multicenter study evaluated 141 patients with symptomatic peripheral arterial disease (PAD) after treatment with heparin-bonded covered stents (VIABAHN(®) Endoprosthesis) or BMS. Clinical outcomes and patency rates were assessed at 1, 6, 12, and 24 months. Mean lesion length was 19.0 ± 6.3 cm in the VIABAHN(®) versus 17.3 ± 6.6 cm in the BMS group. RESULTS: The 24-month primary patency rates in the VIABAHN(®) and BMS group were: intention-to-treat 63.1 (95 % CI 0.52-0.76) versus 41.2 % (95 % CI 0.29-0.57; log rank p = 0.04) and TPP 69.4 (95 % CI 0.58-0.83) versus 40.0 % (95 % CI 0.28-0.56; log rank p = 0.004). Freedom from target-lesion-revascularization (TLR) was 79.4 (95 % CI 0.70-0.90) versus 73.0 % (95 % CI 0.63-0.85) for VIABAHN(®) versus BMS (log rank p = 0.37). For the TPP group in lesions ≥20 cm, the 24-month patency rates were 65.2 (95 % CI 0.50-0.85) versus 26.7 % (95 % CI 0.12-0.59; log rank p = 0.004) for VIABAHN(®) versus BMS, and freedom from TLR was 80.0 (95 % CI 0.68-0.94) versus 61.9 % (95 % CI 0.44-0.87; log rank p = 0.13). The ankle brachial index was 0.89 ± 0.18 versus 0.91 ± 0.17 (p = 0.76) at 24-month in the VIABAHN(®) versus the BMS group, respectively. CONCLUSION: At 24-month, this trial in PAD patients with long femoropopliteal lesions demonstrated a significantly improved primary patency rate for heparin-bonded covered stents compared to BMS, however, without a significant impact on clinical outcomes and TLR rate (Reg. Nr. ISRCTN48164244).

Mechanical thrombectomy with stent retrievers in acute ischemic stroke.

Mechanical thrombectomy (MTE) in patients with acute ischemic infarct caused by large-vessel occlusion is becoming used with increasing frequency in many stroke centers. With the introduction of stent retrievers, recanalization rates >80 % are reached by most operators. However, although the technical success rate of MTE has been increased, clinical results have not improved to the same degree. In this review, the indications for MTE, the technique, and the technical and clinical outcomes are discussed. Complications and predictors for good clinical outcome are described based on recent data from the literature.

Heparin-bonded covered stents versus bare-metal stents for complex femoropopliteal artery lesions: the randomized VIASTAR trial (Viabahn endoprosthesis with PROPATEN bioactive surface [VIA] versus bare nitinol stent in the treatment of long lesions in superficial femoral artery occlusive disease).

OBJECTIVES: The hypothesis that endovascular treatment with covered stents has equal risks but higher efficacy than bare-metal stents (BMS) in long femoropopliteal artery disease was tested. BACKGROUND: Although endovascular treatment of short superficial femoral artery lesions revealed excellent results, efficacy in long lesions remains unsatisfactory. METHODS: In a prospective, randomized, single-blind, multicenter study, 141 patients with symptomatic peripheral arterial disease were assigned to treatment with heparin-bonded, covered stents (Viabahn 72 patients) or BMS (69 patients). Clinical outcomes and patency rates were assessed at 1, 6, and 12 months. RESULTS: Mean ± SD lesion length was 19.0 ± 6.3 cm in the Viabahn group and 17.3 ± 6.6 cm in the BMS group. Major complications within 30 days were observed in 1.4%. The 12-month primary patency rates in the Viabahn and BMS groups were: intention-to-treat (ITT) 70.9% (95% confidence interval [CI]: 0.58 to 0.80) and 55.1% (95% CI: 0.41 to 0.67) (log-rank test p = 0.11); treatment per-protocol (TPP) 78.1% (95% CI: 0.65 to 0.86) and 53.5% (95% CI: 0.39 to 0.65) (hazard ratio: 2.23 [95% CI: 1.14 to 4.34) (log-rank test p = 0.009). In lesions ≥20 cm, (TransAtlantic Inter-Society Consensus class D), the 12-month patency rate was significantly longer in VIA patients in the ITT analysis (VIA 71.3% vs. BMS 36.8%; p = 0.01) and the TPP analysis (VIA 73.3% vs. BMS 33.3%; p = 0.004). Freedom from target lesion revascularization was 84.6% for Viabahn (95% CI: 0.72 to 0.91) versus 77.0% for BMS (95% CI: 0.63 to 0.85; p = 0.37). The ankle-brachial index in the Viabahn group significantly increased to 0.94 ± 0.23 compared with the BMS group (0.85 ± 0.23; p < 0.05) at 12 months. CONCLUSIONS: This randomized trial in symptomatic patients with peripheral arterial disease who underwent endovascular treatment for long femoropopliteal lesions demonstrated significant clinical and patency benefits for heparin-bonded covered stents compared with BMS in lesions ≥20 cm and for all lesions in the TPP analysis. In the ITT analysis for all lesions, which was flawed by major protocol deviations in 8.5% of the patients, the difference was not significant. (GORE VIABAHN® endoprosthesis with bioactive propaten surface versus bare nitinol stent in the treatment of TASC B, C and D lesions in superficial femoral artery occlusive disease; ISRCTN48164244).

The "central vein sign": is there a place for susceptibility weighted imaging in possible multiple sclerosis?

OBJECTIVES: Susceptibility weighted imaging (SWI) may have the potential to depict the perivenous extent of white matter lesions (WMLs) in multiple sclerosis (MS). We aimed to assess the discriminatory value of the "central vein sign" (CVS). METHODS: In a 3-T magnetic resonance imaging (MRI) study, 28 WMLs in 14 patients with at least one circumscribed lesion >5 mm and not more than eight non-confluent lesions >3 mm were prospectively included. Only WMLs in FLAIR images with a maximum diameter of >5 mm were correlated to their SWI equivalent for CVS evaluation. RESULTS: Five patients fulfilled the revised McDonald criteria for MS and nine patients were given alternative diagnoses. Nineteen MS-WMLs and nine non-MS-WMLs >5 mm were detected. Consensus reading found a central vein in 16 out of 19 MS-WMLs (84 %) and in one out of nine non-MS-WMLs (11 %), respectively. The CVS proved to be a highly significant discriminator (P < 0.001) between MS-WMLs and non-MS-WMLs with a sensitivity, specificity, positive and negative predictive value and accuracy of 84 %, 89 %, 94 %, 73 % and 86 %, respectively. Inter-rater agreement was good (κ = 0.77). CONCLUSIONS: Even though the CVS is not exclusively found in MS-WMLs, SWI may be a useful adjunct in patients with possible MS. KEY POINTS: • MRI continues to yield further information concerning MS lesions. • SWI adds diagnostic information in patients with possible MS. • The "central vein sign" was predominantly seen in MS lesions. • The "central vein sign" helps discriminate between MS and non-MS lesions.

Pharmacokinetic analysis after implantation of everolimus-eluting self-expanding stents in the peripheral vasculature.

BACKGROUND: A novel self-expanding drug-eluting stent was designed to release everolimus 225 µg/cm(2) to prevent restenosis following peripheral arterial intervention. The purpose of this study was to measure the pharmacokinetic profile of everolimus following stent implantation. METHODS: One hundred four patients with symptomatic peripheral arterial disease underwent implantation of everolimus-eluting stents in the femoropopliteal arteries. In a prespecified subset of 26 patients, blood samples for assay of everolimus content were collected prior to stent implantation, at 1, 4, and 8 hours postprocedure, prior to discharge, and at 1 month postprocedure. RESULTS: A total of 39 stents, ranging from 28 mm to 100 mm in length, were implanted in 26 patients, resulting in a total delivered everolimus dose range of 3.0 to 7.6 mg. Following the procedure, the maximum observed everolimus blood concentrations (C(max)) varied from 1.83 ± 0.05 ng/mL after implantation of a single 80-mm stent to 4.66 ± 1.78 ng/mL after implantation of two 100-mm stents. The mean time to peak concentration (T(max)) varied from 6.8 hours to 35 hours. The pharmacokinetics of everolimus were dose-proportional in that dose-normalized C(max) and area under the curve values were constant over the studied dose range. CONCLUSIONS: After implantation of everolimus-eluting self-expanding stents in the femoropopliteal arteries, systemic blood concentrations of everolimus are predictable and considerably lower than blood concentrations observed following safe oral administration of everolimus.

Dual-energy CT angiography in peripheral arterial occlusive disease-accuracy of maximum intensity projections in clinical routine and subgroup analysis.

OBJECTIVE: To evaluate the accuracy of dual-energy CT angiography (DE-CTA) maximum intensity projections (MIPs) in symptomatic peripheral arterial occlusive disease (PAOD). METHODS: In 58 patients, DE-CTA of the lower extremities was performed on dual-source CT. In a maximum of 35 arterial segments, severity of the most stenotic lesion was graded (<10%, 10-49% and 50-99% luminal narrowing or occlusion) independently by two radiologists, with DSA serving as the reference standard. RESULTS: In DSA, 52.3% of segments were significantly stenosed or occluded. Agreement of DE-CTA MIPs with DSA was good in the aorto-iliac and femoro-popliteal regions (κ = 0.72; κ = 0.66), moderate in the crural region (κ = 0.55), slight in pedal arteries (κ = 0.10) and very good in bypass segments (κ = 0.81). Accuracy was 88%, 78%, 74%, 55% and 82% for the respective territories and moderate (75%) overall, with good sensitivity (84%) and moderate specificity (67%). Sensitivity and specificity was 82% and 76% in claudicants and 84% and 61% in patients with critical limb ischaemia. CONCLUSION: While correlating well with DSA above the knee, accuracy of DE-CTA MIPs appeared to be moderate in the calf and largely insufficient in calcified pedal arteries, especially in patients with critical limb ischaemia.

When coughing can cause stroke--a case-based update on cerebral air embolism complicating biopsy of the lung.

Introducing gas to the circulation is a largely iatrogenic problem which can result in serious morbidity and even death. We report a case of CT-guided needle biopsy of a pulmonary lesion complicated by acute stroke. The English literature on cerebral air embolism is reviewed, including an update of current opinions on its pathomechanism, diagnostic findings, therapeutic strategies, and means of prevention.