Twelve-Month Outcomes From the Japanese Post-Market Surveillance Study of the Viabahn Endoprosthesis as Treatment for Symptomatic Peripheral Arterial Disease in the Superficial Femoral Arteries

Purpose: To assess the midterm safety and effectiveness of the Gore® Viabahn® Endoprosthesis as treatment for symptomatic peripheral arterial disease (PAD) in the superficial femoral arteries (SFA). Materials and Methods: A prospective, multicenter, post-market surveillance study was conducted in Japan. Patients with symptomatic SFA lesions ≥ 10 cm and reference vessel diameters ranging from 4.0 to 7.5 mm were eligible for enrollment; patients with traumatic or iatrogenic vessel injury in the thoracic, abdominal, or pelvic arteries were excluded. Outcomes evaluated at 12 months were primary patency (PP), primary-assisted patency (PAP), secondary patency (SP), freedom from target lesion revascularization (fTLR), occurrence of device- or procedure-related serious adverse events (SAEs), and stent fractures. Results: From August 2016 to May 2017, 321 patients were enrolled at 64 Japanese sites (mean age, 73.9±8.7 years; 77.3% male). Hypertension, diabetes, and end stage renal disease were present in 84.4%, 54.8%, and 23.1% of patients, respectively. Mean lesion length was 23.6 cm±6.6 cm, with lesions ≥ 15 cm in 271 patients (84.4%). TASC C/D lesions accounted for 86.6% (39.1% TASC C, 47.5% TASC D); 26.5% had critical limb ischemia. Baseline ABI was 0.60±0.16. A total of 562 devices were implanted in 324 limbs, with a majority of patients (68.8%) receiving 2 stents. Through 12 months, 92.1% of patients were evaluable. Kaplan-Meier-estimated PP, PAP, and SP at 12 months was 85.6%, 91.7%, and 94.8%, respectively. Twelve-month fTLR was 92.3%. Mean change in ABI at 12 months was 0.343±0.21; mean improvement in Rutherford class was 2.5. Device- or procedure-related SAEs occurred in 3.1% through 30 days, with a majority of early SAEs consisting of access complications. Through 12 months, a cumulative 10.6% had device- or procedure-related SAEs, with the most common being device occlusions in 4.0%. Lower limb amputation occurred in 0.9% and was related to pre-existing ulceration or gangrene in all 3 cases. No stent fractures were observed at 12-month x-ray evaluation. Conclusion: In a real-world Japanese patient population characterized by long SFA lesions and complex PAD, the Viabahn endoprosthesis was associated with excellent patency rates through 12 months and an acceptable safety profile.

3D modelling of drug-coated balloons for the treatment of calcified superficial femoral arteries

Background/Objectives Drug-coated balloon therapy for diseased superficial femoral arteries remains controversial. Despite its clinical relevance, only a few computational studies based on simplistic two-dimensional models have been proposed to investigate this endovascular therapy to date. This work addresses the aforementioned limitation by analyzing the drug transport and kinetics occurring during drug-coated balloon deployment in a three-dimensional geometry. Methods An idealized three-dimensional model of a superficial femoral artery presenting with a calcific plaque and treated with a drug-coated balloon was created to perform transient mass transport simulations. To account for the transport of drug (i.e. paclitaxel) released by the device, a diffusion-reaction equation was implemented by describing the drug bound to specific intracellular receptors through a non-linear, reversible reaction. The following features concerning procedural aspects, pathologies and modelling assumptions were investigated: (i) balloon application time (60–180 seconds); (ii) vessel wall composition (healthy vs. calcified wall); (iii) sequential balloon application; and (iv) drug wash-out by the blood stream vs. coating retention, modeled as exponential decay. Results The balloon inflation time impacted both the free and specifically-bound drug concentrations in the vessel wall. The vessel wall composition highly affected the drug concentrations. In particular, the specifically-bound drug concentration was four orders of magnitude lower in the calcific compared with healthy vessel wall portions, primarily as a result of reduced drug diffusion. The sequential application of two drug-coated balloons led to modest differences (~15%) in drug concentration immediately after inflation, which became negligible within 10 minutes. The retention of the balloon coating increased the drug concentration in the vessel wall fourfold. Conclusions The overall findings suggest that paclitaxel kinetics may be affected not only by the geometrical and compositional features of the vessel treated with the drug-coated balloon, but also by balloon design characteristics and procedural aspects that should be carefully considered.

Transcatheter aortic valve replacement using the iSleeve expandable sheath in small femoral arteries

BackgroundSmall femoral arteries have been associated with a higher risk of vascular complications in transfemoral transcatheter aortic valve replacement (TAVR). We investigated the feasibility and safety of TAVR in patients with small femoral arteries.MethodsIn this observational study, we included 82 patients who underwent transfemoral TAVR with the ACURATE neo system using the expandable 14F iSleeve sheath between 2018 and 2019 at Karolinska University Hospital, Sweden. Of these, 41 patients had a minimal femoral artery diameter of ≥5.5 mm (mean 6.5, range 5.5–9.2), and 41 patients had a minimal femoral artery diameter <5.5 mm (mean 4.9, range 3.9–5.4).ResultsThere was no significant difference in major vascular and bleeding complications between the small femoral artery group (7%) and the normal femoral artery group (2%) (p=0.62). The total of major and minor vascular complications did not differ significantly according to femoral artery size (17% vs 5%) (p=0.16). The iSleeve sheath was not correlated with any of the complications. The use of the iSleeve sheath was unsuccessful in four patients (5%), of which one patient had a small femoral artery diameter.ConclusionTransfemoral TAVR with the ACURATE neo system using the iSleeve sheath is a promising method for patients with small femoral arteries even though we found a trend towards higher rates of complications in these patients. The use of expandable sheaths may expand the spectrum of patients that can be treated with transfemoral TAVR, and thus may improve the prognosis in patients with severe aortic valve stenosis.

Enhanced Vasoconstriction Mediated by α1-Adrenergic Mechanisms in Small Femoral Arteries in Newborn Llama and Sheep Gestated at Low and High Altitudes

The authors previously demonstrated that newborn llama (NBLL) express high levels of α1 adrenergic receptors, which provide a potent vasoconstriction response when compared with newborn sheep (NBSH) gestated at sea level. However, data regarding the impact of chronic gestational hypobaric hypoxia on α-adrenergic vasoconstriction in the neonatal life has not been studied. We evaluated if gestation under chronic hypobaric hypoxia modifies α1-adrenergic vasoconstrictor function in NBLL and NBSH. We compared the vasoconstrictor response induced by potassium and α-adrenergic stimuli in isolated small femoral arteries of NBLL and NBSH gestated at high altitude (HA; 3,600 m) or low altitude (LA; 580 m). The maximal contraction (RMAX) and potency (EC50) to potassium, noradrenaline (NA), and phenylephrine (PHE) were larger in HA-NBLL than LA-NBLL. RMAX to potassium, NA, and PHE were lower in HA-NBSH when compared with LA-NBSH and potency results were similar. Competitive blockade with prazosin showed that RNLL LA/HA have a similar pA2. In contrast, NBSH had increased pA2 values in HA when compared with LA. Finally, small femoral arteries denudated or treated with LNAME in LA and HA lacked NO or endothelium participation in response to PHE stimulation. In contrast, NBSH displayed that denudation or blockade with LNAME support NO or endothelium participation in response to PHE activation. In conclusion, HA chronic hypoxia enhances α1 adrenergic receptor activity in small femoral arteries in NBLL to a higher degree than NBSH, implying a higher vasoconstriction function.

First experiences of local pulse wave velocity measurements in 4D-MRI in focally stented femoropopliteal arteries

Summary: Background: In peripheral arterial disease (PAD) the femoropopliteal (FP) artery is the most frequently recanalized lower limb artery. Stent-based interventions change the biomechanical properties of FP arteries. However, no clinical tool for functional imaging is established for quantitative measurements in vivo. Four-dimensional-flow magnetic resonance imaging enables a detailed evaluation of the hemodynamics of the central and – more challenging – the peripheral arteries. The present study aimed to determine the feasibility of assessing pulse wave velocities (PWV) as a marker of vessel stiffness in PAD patients with multiple spot stents and to compare the values with age-matched subjects and young-adult healthy subjects. Patients and methods: Contrast-free 4D-flow MRI was performed in seven PAD patients with focally stented FP arteries, five age-matched subjects after exclusion of PAD, and five young, healthy adults. PWV values were calculated from flow curves by using the foot-to-foot method. Results: Four-D-flow MRI sequences offering high spatial and temporal resolution enables quantification of flow velocity measurements and estimation of PWVs. Assessment of segmental PWV as a surrogate of vascular stiffness in focally stented femoral arteries is feasible. PWV values across all groups were 15.6±5.2 m/s, 13.3±4.1 m/s, and 9.9±2.2 m/s in PAD patients, senior-aged volunteers, and young-adult volunteers respectively. PWV values in PAD patients were similar with those in the senior-aged volunteers group (15.6±5.2 vs. 13.3 ±4.1 years, p=0.43). However, when compared to the young-adult volunteers, PAD patients had a statistically significantly higher mean local PWV (15.6±5.2 m/s vs. 9.9±2.2 m/s, p<0.05). Conclusions: Calculating segmental PWV in the femoral arteries is feasible in PAD patients with focally stented FP arteries. PWV values in PAD patients were similar to those in senior-aged volunteers, both of which were higher than in young-adult volunteers.