Patient-specific computational flow simulation reveals significant differences in paravisceral aortic hemodynamics between fenestrated and branched endovascular aneurysm repair.

Background: Endovascular aneurysm repair with four-vessel fenestrated endovascular aneurysm repair (fEVAR) or branched endovascular aneurysm repair (bEVAR) currently represent the forefront of minimally invasive complex aortic aneurysm repair. This study sought to use patient-specific computational flow simulation (CFS) to assess differences in postoperative hemodynamic effects associated with fEVAR vs bEVAR. Methods: Patients from two institutions who underwent four-vessel fEVAR with the Cook Zenith Fenestrated platform and bEVAR with the Jotec E-xtra Design platform were retrospectively selected. Patients in both cohorts were treated for paravisceral and extent II, II, and V thoracoabdominal aortic aneurysms. Three-dimensional finite element volume meshes were created from preoperative and postoperative computed tomography scans. Boundary conditions were adjusted for body surface area, heart rate, and blood pressure. Pulsatile flow simulations were performed with equivalent boundary conditions between preoperative and postoperative states. Postoperative changes in hemodynamic parameters were compared between the fEVAR and bEVAR groups. Results: Patient-specific CFS was performed on 20 patients (10 bEVAR, 10 fEVAR) with a total of 80 target vessels (40 renal, 20 celiac, 20 superior mesenteric artery stents). bEVAR was associated with a decrease in renal artery peak flow rate (-5.2% vs +2.0%; P < .0001) and peak pressure (-3.4 vs +0.1%; P < .0001) compared with fEVAR. Almost all renal arteries treated with bEVAR had a reduction in renal artery perfusion (n = 19 [95%]), compared with 35% (n = 7) treated with fEVAR. There were no significant differences in celiac or superior mesenteric artery perfusion metrics (P = .10-.27) between groups. Time-averaged wall shear stress in the paravisceral aorta and branches also varied significantly depending on endograft configuration, with bEVAR associated with large postoperative increases in renal artery (+47.5 vs +13.5%; P = .002) and aortic time-averaged wall shear stress (+200.1% vs -31.3%; P = .001) compared with fEVAR. Streamline analysis revealed areas of hemodynamic abnormalities associated with branched renal grafts which adopt a U-shaped geometry, which may explain the observed differences in postoperative changes in renal perfusion between bEVAR and fEVAR. Conclusions: bEVAR may be associated with subtle decreases in renal perfusion and a large increase in aortic wall shear stress compared with fEVAR. CFS is a novel tool for quantifying and visualizing the unique patient-specific hemodynamic effect of different complex EVAR strategies. Clinical Relevance: This study used patient-specific CFS to compare postoperative hemodynamic effects of four-vessel fenestrated endovascular aneurysm repair (fEVAR) and branched endovascular aneurysm repair (bEVAR) in patients with complex aortic aneurysms. The findings indicate that bEVAR may result in subtle reductions in renal artery perfusion and a significant increase in aortic wall shear stress compared with fEVAR. These differences are clinically relevant, providing insights for clinicians choosing between these approaches. Understanding the patient-specific hemodynamic effects of complex EVAR strategies, as revealed by CFS, can aid in future personalized treatment decisions, and potentially reduce postoperative complications in aortic aneurysm repair.

Deep-learning approach to automate the segmentation of aorta in non-contrast CTs.

Purpose: Segmentation of vascular structures in preoperative computed tomography (CT) is a preliminary step for computer-assisted endovascular navigation. It is a challenging issue when contrast medium enhancement is reduced or impossible, as in the case of endovascular abdominal aneurysm repair for patients with severe renal impairment. In non-contrast-enhanced CTs, the segmentation tasks are currently hampered by the problems of low contrast, similar topological form, and size imbalance. To tackle these problems, we propose a novel fully automatic approach based on convolutional neural network. Approach: The proposed method is implemented by fusing the features from different dimensions by three kinds of mechanisms, i.e., channel concatenation, dense connection, and spatial interpolation. The fusion mechanisms are regarded as the enhancement of features in non-contrast CTs where the boundary of aorta is ambiguous. Results: All of the networks are validated by three-fold cross-validation on our dataset of non-contrast CTs, which contains 5749 slices in total from 30 individual patients. Our methods achieve a Dice score of 88.7% as the overall performance, which is better than the results reported in the related works. Conclusions: The analysis indicates that our methods yield a competitive performance by overcoming the above-mentioned problems in most general cases. Further, experiments on our non-contrast CTs demonstrate the superiority of the proposed methods, especially in low-contrast, similar-shaped, and extreme-sized cases.

Patient-specific finite element simulation of peripheral artery percutaneous transluminal angioplasty to evaluate the procedure outcome without stent implantation.

The purpose of this work is to present a patient-specific (PS) modeling approach for simulating percutaneous transluminal angioplasty (PTA) endovascular treatment and assessing the balloon sizing influence on short-term outcomes in peripheral arteries, i.e. without stent implantation. Two 3D PS stenosed femoral artery models, one with a dominant calcified atherosclerosis while the other with a lipidic plaque, were generated from pre-operative computed tomography angiography images. Elastoplastic constitutive laws were implemented within the plaque and artery models. Implicit finite element method (FEM) was used to simulate the balloon inflation and deflation for different sizings. Besides vessel strains, results were mainly evaluated in terms of the elastic recoil ratio (ERR) and lumen gain ratio (LGR) attained immediately after PTA. Higher LGR values were shown within the stenosed region of the lipidic patient. Simulated results also showed a direct and quantified correlation between balloon sizing and LGR and ERR for both patients after PTA, with a more significant influence on the lumen gain. The max principal strain values in the outer arterial wall increased at higher balloon sizes during inflation as well, with higher rates of increase when the plaque was calcified. Results show that our model could serve in finding a compromise for each stenosis type: maximizing the achieved lumen gain after PTA, but at the same time without damaging the arterial tissue. The proposed methodology can serve as a step toward a clinical decision support system to improve angioplasty balloon sizing selection prior to the surgery.

A Multicenter, Investigator-Blinded, Randomized Controlled Trial to Assess the Efficacy of Calf Neuromuscular Electrical Stimulation Program on Walking Performance in Peripheral Artery Disease: The ELECTRO-PAD Study Protocol.

This paper describes a currently on-going multicenter, randomized controlled trial designed to assess the efficacy of calf neuromuscular electrical stimulation (NMES) on changes in maximal walking distance in people with lower extremity peripheral artery disease (PAD), compared with a non-intervention control-group. This study (NCT03795103) encompasses five participating centers in France. PAD participants with a predominant claudication at the calf level and a maximal treadmill walking distance ≤300 m are randomized into one of the two groups: NMES group or Control group. The NMES program consists of a 12-week program of electrical stimulations at the calf-muscle level. The primary outcome of the study is the change in maximal treadmill walking distance at 12 weeks. Main secondary outcomes include changes in the pain-free treadmill walking distance; 6 min total walking distance; global positioning system (GPS)-measured outdoor walking capacity; daily physical activity level by accelerometry; self-reported walking impairment; self-reported quality of life; ankle-brachial index; and skin microvascular function, both at the forearm and calf levels. Recruitment started in September 2019 and data collection is expected to end in November 2022.

Stretched reconstruction based on 2D freehand ultrasound for peripheral artery imaging.

PURPOSE: Endovascular revascularization is becoming the established first-line treatment of peripheral artery disease (PAD). Ultrasound (US) imaging is used pre-operatively to make the first diagnosis and is often followed by a CT angiography (CTA). US provides a non-invasive and non-ionizing method for the visualization of arteries and lesion(s). This paper proposes to generate a 3D stretched reconstruction of the femoral artery from a sequence of 2D US B-mode frames. METHODS: The proposed method is solely image-based. A Mask-RCNN is used to segment the femoral artery on the 2D US frames. In-plane registration is achieved by aligning the artery segmentation masks. Subsequently, a convolutional neural network (CNN) predicts the out-of-plane translation. After processing all input frames and re-sampling the volume according to the vessel's centerline, the whole femoral artery can be visualized on a single slice of the resulting stretched view. RESULTS: 111 tracked US sequences of the left or right femoral arteries have been acquired on 18 healthy volunteers. fivefold cross-validation was used to validate our method and achieve an absolute mean error of 0.28 ± 0.28 mm and a median drift error of 8.98%. CONCLUSION: This study demonstrates the feasibility of freehand US stretched reconstruction following a deep learning strategy for imaging the femoral artery. Stretched views are generated and can give rich diagnosis information in the pre-operative planning of PAD procedures. This visualization could replace traditional 3D imaging in the pre-operative planning process, and during the pre-operative diagnosis phase, to identify, locate, and size stenosis/thrombosis lesions.

Prospective Multicentre Cohort Study of Fenestrated and Branched Endografts After Failed Endovascular Infrarenal Aortic Aneurysm Repair with Type Ia Endoleak.

OBJECTIVE: Failed endovascular infrarenal aortic aneurysm repair (EVAR) due to development of late type Ia endoleak exposes patients to the risk of rupture and should be treated. The purpose of this study was to evaluate the results of fenestrated/branched EVAR (F/BEVAR) for treatment of failed EVAR with type Ia endoleak. METHODS: From January 2010 to December 2019, a prospective multicentre study was conducted (ClinicalTrials.gov identifier: NCT04532450) that included 85 consecutive patients who had undergone F/BEVAR to treat a type Ia endoleak following EVAR. The primary outcome was overall freedom from any re-intervention or death related to the F/BEVAR procedure. RESULTS: In 30 cases (35%) EVAR was associated with a short < 10 mm or angulated (> 60°) infrarenal aortic neck, poor placement of the initial stent graft (n = 3, 4%), sizing error (n = 2, 2%), and/or stent graft migration (n = 7, 8%). Type Ia endoleak was observed after a period of 59 ± 25 months following EVAR. The authors performed 82 FEVAR (96%) and three BEVAR (4%) procedures with revascularisation of 305 target arteries. Overall technical success was 94%, with three failures including one persistent Type Ia endoleak and two unsuccessful stent graft implantations. Intra-operative target artery revascularisation was successful in 303 of 305 attempts. The in hospital mortality rate was 5%. Cardiac, renal and pulmonary complications occurred in 6%, 14%, and 7% of patients, respectively. Post-operative spinal cord ischaemia occurred in four patients (4.7%). At three years, the survival rate was 64% with overall freedom from any re-intervention or aneurysm related death of 40%, and freedom from specific F/BEVAR re-intervention of 73%. At three years, the secondary patency rate of the target visceral arteries was 96%. During follow up, 27 patients (33%) required a revision procedure of the fenestrated (n = 11) or index EVAR stent graft (n = 16), including six open conversions. CONCLUSION: While manufactured F/BEVAR was effective in treating type Ia endoleak in patients with failed EVAR, it was at the cost of a number of secondary endovascular and open surgical procedures.

A Randomized Trial Comparing Polymer Versus Suture-Based Vascular Closure Devices for Arterial Closure Following Lower-Limb Arterial Endovascular Revascularization.

PURPOSES: The primary objective of this study (STEP trial) was to compare the efficacy of the polymer-based FemoSeal® vascular closure device (VCD) and the suture-based ProGlide® VCD in achieving hemostasis at the femoral access site after lower-limb arterial endovascular revascularization. MATERIALS AND METHODS: STEP was a multicenter randomized clinical trial including patients undergoing lower-limb arterial endovascular revascularization. The primary endpoint was technical success 5 h after the VCD intervention, defined as achievement of hemostasis without the need for a follow-up intervention at the access site and without a 2-g/dL drop in hemoglobin. RESULTS: Between December 2017 and April 2019, 113 patients were assigned to the FemoSeal® group (FS) and 117 to the ProGlide® group (PG). VCD interventions were technically successful for 90 FS patients (80%) and 58 PG patients (50%) (odds ratio, 3.98; 95% CI, 2.22 to 7.14; p < 0.0001). This difference in success rates between FS and PG is partly explained by more frequent recourse to manual compression (FS: n = 19; PG: n = 45) and an additional VCD (FS: n = 0; PG: n = 23) in the latter group. After 5 h, 87% of FS patients and 69% of PG patients resumed ambulation (odds ratio: 3.07; 95% CI: 1.93 to 6.15; p = 0.0016). CONCLUSIONS: In patients undergoing lower-limb arterial endovascular revascularization, FemoSeal® was superior to ProGlide® in terms of technical success. CLINICAL TRIAL REGISTRATION: Step trial was registered on http://ClinicalTrials.gov (NCT03192033).

Influence of balloon design, plaque material composition, and balloon sizing on acute post angioplasty outcomes: An implicit finite element analysis.

In this work we propose a generic modeling approach for simulating percutaneous transluminal angioplasty (PTA) endovascular treatment, and evaluating the influence of balloon design, plaque composition, and balloon sizing on acute post-procedural outcomes right after PTA, without stent implantation. Clinically-used PTA balloons were classified into two categories according to their compliance characteristics, and were modeled correspondingly. Self-defined elastoplastic constitutive laws were implemented within the plaque and artery models, after calibration based on experimental and clinical data. Finite element method (FEM) implicit solver was used to simulate balloon inflation and deflation. Besides balloon profile at max inflation, results are mainly assessed in terms of the elastic recoil ratio (ERR) and lumen gain ratio (LGR) obtained immediately after PTA. No variations in ERR nor LGR values were detected when the balloon design changed, despite the differences observed in their profile at max inflation. Moreover, LGR and ERR inversely varied with the augmentation of calcification level within the plaque (-11% vs. +4% respectively, from fully lipidic to fully calcified plaque). Furthermore, results showed a direct correlation between balloon sizing and LGR and ERR, with noticeably higher rates of change for LGR (+18% and +2% for LGR and ERR respectively for a calcified plaque and a balloon pressure increasing from 10 to 14 atm). However a larger LGR comes with a higher risk of arterial rupture. This proposed methodology opens the way for evaluation of angioplasty balloon selections towards clinical procedure optimization.

"Should I stay or should I go now?" Recovery time effect on walking capacity in symptomatic peripheral artery disease.

The objective of the study was to investigate the effect of recovery time on walking capacity (WC) throughout repeated maximal walking bouts in symptomatic lower-extremity peripheral artery disease (PAD). The effect of recovery time on WC (maximal walking time) was determined in 21 participants with PAD in three experimental conditions [recovery time from 0.5 to 9.5 min + a self-selected recovery time (SSRT)]: 1) 11 repeated sequences of two treadmill walking bouts (TW-ISO); 2) a single sequence of seven treadmill walking bouts (TW-CONS); 3) a single sequence of seven outdoor walking bouts (OW-CONS). Exercise transcutaneous oxygen pressure changes were continuously recorded as an indirect measure of ischemia. An individual recovery time (IRT) beyond which WC did not substantially increased was determined in participants with a logarithmic fit. At the group level, mixed models showed a significant effect (P < 0.001) of recovery time on WC restoration. At the participant level, strong logarithmic relationships were found (median significant R2 ≥ 0.78). The median SSRT corresponded to a median work-to-rest ratio >1:1 (i.e., a lower recovery time in view of the corresponding previous walking time) and was related to unrecovered ischemia and a WC restoration level of <80%. A median work-to-rest ratio of ≤1:2 allowed full recovery of ischemia and full restoration of WC. The IRT ratio was between 1:1 and 1:2 and corresponded to the start of recovery from ischemia. Recovery time affects the restoration level of WC during repeated maximal walking bouts in symptomatic PAD. Meaningful variations in WC restoration were related to specific levels of work-to-rest ratios.NEW & NOTEWORTHY This study demonstrated that there is a significant and mostly logarithmic effect of recovery time on walking capacity in people with symptomatic PAD. This study revealed that a median work-to-rest ratio >1:1 leads to the resumption of walking with unrecovered ischemia and precludes the restoration of full walking capacity, whereas a work-to-rest ratio ≤1:2 allowed walking capacity to fully be restored.

Current results of left gonadal vein transposition to treat nutcracker syndrome.

OBJECTIVE: Nutcracker syndrome can cause disabling chronic pain requiring surgical intervention. At present, data describing a straightforward management approach are lacking. Transposition of the left gonadal vein is one of the surgical therapeutic alternatives. The aim of the present study was to describe our clinical results with gonadal vein transposition. METHODS: All 11 patients from three centers who had undergone left gonadal vein transposition for nutcracker syndrome from 2016 to 2019 were retrospectively included. The surgical cases were mainly selected according to the morphologic criteria of the left gonadal vein. The diameter and length dictated the type of approach (laparotomy or retroperitoneal) and the transposition level. A minimally invasive retroperitoneal approach was preferred. Pain was assessed using a numeric rating scale. RESULTS: We included 11 patients (10 women) with a median age of 35 years (range, 25-69). Preoperative computed tomography angiography showed anterior nutcracker syndrome in 10 patients (91%). All 11 patients had experienced lower back and/or pelvic pain, which was associated with pelvic congestion syndrome in 6 patients (55%) and hematuria in 5 patients (45%). The median preoperative numeric rating scale score for pain was 7.0 (range, 3.5-10.0) and 6.0 (range, 3.5-8.0) for lower back pain and pelvic pain, respectively. At the level of the iliac vein crossing (external or common), the median diameter of the left gonadal vein was 7.87 mm (range, 6.45-11.28). The left gonadal vein was transposed to the inferior vena cava in one case (9%), the left external iliac vein in five (45%), and the left common iliac vein in five cases (45%). The median in-hospital stay was 4 days (range, 2-20 days). Two early complications (18%) requiring surgical revision occurred: one of active bleeding and one hematoma. The median follow-up was 15 months (range, 6-44 months). The median postoperative pain score was 1.0 (range, 0.0-4.0) and 0.0 (range, 0.0-6.0) for lower back and pelvic pain, respectively. Incisional and/or neuropathic pain was noted, with a median score of 3.5 (range, 1.0-6.0) in seven patients (64%). Two late complications (18%) were observed: one case of thrombosis and one case of anastomotic stenosis. The hematuria had disappeared in all patients who had presented with it initially. CONCLUSIONS: Left gonadal vein transposition can be proposed as a first approach if the diameter of the left gonadal vein is sufficient to perform the anastomosis. It is an easily achievable, minimally invasive alternative that achieves satisfactory results without the use of foreign material.

Use of rifampicin and graft removal are associated with better outcomes in prosthetic vascular graft infection.

OBJECTIVES: Prosthetic vascular graft infection (PVGI) is a very severe disease. We aimed to determine the factors associated with treatment failure. METHODS: Patients admitted to two University Hospitals with PVGI were included in this retrospective study. PVGI was classified as possible, probable or proven according to an original set of diagnostic criteria. We defined treatment failure if one of the following events occurred within the first year after PVGI diagnosis: death and infection recurrence due to the same or another pathogen. RESULTS: One hundred and twelve patients were diagnosed with possible (n = 26), probable (n = 22) and proven (n = 64) PVGI. Bacterial documentation was obtained for 81% of patients. The most frequently identified pathogen was Staphylococcus aureus (n = 39). Surgery was performed in 96 patients (86%). Antibiotics were administered for more than 6 weeks in 41% of patients. Treatment failure occurred in 30 patients (27.5%). The factors associated with a lower probability of treatment failure were total removal of the infected graft (OR = 0.2, 95% CI [0.1-0.6]), rifampicin administration (OR = 0.3 [0.1-0.9]) and possible PVGI according to the GRIP criteria (OR = 0.3 [0.1-0.9]). CONCLUSIONS: Treatment failure occurred in 27.5% of patients with PVGI. Total removal of the infected graft and rifampicin administration were associated with better outcomes.

Editor's Choice - A Cost Effectiveness Analysis of Outpatient versus Inpatient Hospitalisation for Lower Extremity Arterial Disease Endovascular Revascularisation in France: A Randomised Controlled Trial.

OBJECTIVE: The AMBUVASC trial evaluated the cost effectiveness of outpatient vs. inpatient hospitalisation for endovascular repair of lower extremity arterial disease (LEAD). METHODS: AMBUVASC was a national multicentre, prospective, randomised controlled trial conducted in nine public and two private French centres. The primary endpoint was the incremental cost effectiveness ratio (ICER), defined by cost per quality adjusted life year (QALY). Analysis was conducted from a societal perspective, excluding indirect costs, and considering a one month time horizon. RESULTS: From 16 February 2016 to 29 May 2017, 160 patients were randomised (80 per group). A modified intention to treat analysis was performed with 153 patients (outpatient hospitalisation: n = 76; inpatient hospitalisation: n = 77). The patients mainly presented intermittent claudication (outpatient arm: 97%; inpatient arm: 92%). Rates of peri-operative complications were 20% (15 events) and 18% (14 events) for the outpatient and inpatient arms respectively (p = .81). Overall costs (difference: €187.83; 95% confidence interval [CI] -275.68-651.34) and QALYs (difference: 0.00277; 95% CI -0.00237 - 0.00791) were higher for outpatients due to more re-admissions than the inpatient arm. The mean ICER was €67 741 per QALY gained for the base case analysis with missing data imputed using multiple imputation by predictive mean matching. The outpatient procedure was not cost effective for a willingness to pay of €50 000 per QALY and the probability of being cost effective was only 59% for a €100 000/QALY threshold. CONCLUSION: Outpatient hospitalisation is not cost effective compared with inpatient hospitalisation for endovascular repair of patients with claudication at a €50 000/QALY threshold.

Fusion Imaging with a Mobile C-Arm for Peripheral Arterial Disease.

BACKGROUND: Fusion imaging makes it possible to improve endovascular procedures and is mainly used in hybrid rooms for aortic procedures. The objective of this study was to evaluate the feasibility of fusion imaging for femoropopliteal endovascular procedures with a mobile flat plane sensor and dedicated software to assist endovascular navigation. MATERIALS AND METHODS: Between May and December 2017, 41 patients requiring femoropopliteal endovascular revascularization were included. Interventions were carried out in a conventional surgical room equipped with a mobile plane sensor (Cios Alpha, Siemens). The numerical video stream was transmitted to an angionavigation station (EndoNaut (EN), Therenva). The software created an osseous and arterial panorama of the treated limb from the angiographies carried out at the beginning of procedure. After each displacement of the table, the software relocated the current image on the osseous panorama, with 2D-2D resetting, and amalgamated the mask of the arterial panorama. The success rates of creation of osseous and arterial panorama and the success of relocation were evaluated. The data concerning irradiation, the volume of contrast (VC) injected, and operative times were recorded. RESULTS: Osseous panoramas could be automatically generated for the 41 procedures, without manual adjustment in 33 cases (80.5%). About 35 relocations based on a 2D-2D resetting could be obtained in the 41 procedures, with a success rate of 85%. The causes of failure were a change in table height or arch angulation. The average duration of intervention was 74.5 min. The irradiation parameters were duration of fluoroscopy 17.8 ± 13.1 min, air kerma 80.5 ± 68.4 mGy, and dose area product 2140 ± 1599 µGy m2. The average VC was 24.5 ± 14 mL. CONCLUSIONS: This preliminary study showed that fusion imaging is possible in a nonhybrid room for peripheral procedures. Imagery of mobile C-arms can be improved for femoropopliteal endovascular procedures without heavy equipment. These imagery tools bring an operative comfort and could probably reduce irradiation and the injected VC. The clinical benefit must be evaluated in more patients in a randomized comparative study with a rigorous methodology.

Numerical simulation of fenestrated graft deployment: Anticipation of stent graft and vascular structure adequacy.

Fenestrated endovascular aneurism repair (FEVAR) is a minimally invasive technique, and its success depends on the adequacy of the correspondence between the visceral arteries ostia and position of the fenestrations of the stent graft (SG) during its deployment in juxtarenal aneurisms. However, the fenestration position is generally determined from a preoperative computerised tomography (CT) scan, without considering the vascular deformation induced by the insertion of the endovascular tools. Catheterisation difficulties may occur during clinical procedures. Accordingly, the objective of this work is to present an initial proof of concept aimed at anticipating and optimising the position of the fenestrations, while considering the vascular deformation induced by the insertion of the endovascular tools. The proposed method relies on the finite element method to simulate the SG deployment in a vascular structure (VS), and considers the vascular deformation induced by the tools. After determining the optimal simulation parameters for a patient-specific case, the robustness of the method is demonstrated on six other representative anatomies. The simulated SG is also compared with post-deployment CT observations, and demonstrates good adequacy. The results show that the numerically corrected fenestration positions, as determined from the simulated results following the insertion of the endovascular tools, deviate from those of the standard plan (as determined from the preoperative CT scan). This indicates that the SG-VS adequacy could be improved via simulation-based planning, to anticipate potential catheterisation difficulties.

A Polymer-Free Paclitaxel-Eluting Stent Versus a Bare-Metal Stent for De Novo Femoropopliteal Lesions: The BATTLE Trial.

OBJECTIVES: The primary objective of the BATTLE (Bare Metal Stent vs. Paclitaxel Eluting Stent in the Setting of Primary Stenting of Intermediate-Length Femoropopliteal Lesions) trial is to demonstrate the clinical superiority of the Zilver PTX stent over the Misago stent in the treatment of femoropopliteal lesions. BACKGROUND: No randomized studies have compared self-expanding paclitaxel-eluting stents with bare-metal stents in the treatment of femoropopliteal lesions. METHODS: BATTLE is a multicenter randomized controlled trial in patients with symptomatic (Rutherford category 2 to 5) de novo lesions of the superficial femoral or proximal popliteal artery. The primary endpoint is freedom from in-stent restenosis (ISR) at 1 year, with restenosis defined as a peak systolic velocity index >2.4 at the target lesion. The Kaplan-Meier method was used to evaluate time-to-event data for freedom from ISR over the 2-year follow-up period. RESULTS: Between March 2014 and August 2016, 186 patients were enrolled; 91 were assigned to the Misago arm and 90 to the Zilver PTX arm. Kaplan-Meier 1-year estimates of freedom from ISR were 88.6% for Misago and 91% for Zilver PTX (hazard ratio [HR]: 1.2; 95% confidence interval [CI]: 0.6 to 2.4; p = 0.64). Comparing Misago with Zilver PTX, 2-year estimates were 6.4% and 1.2% (HR: 7.3; 95% CI: 0.9 to 59.3; p = 0.0632) for mortality, 74.6% and 78.8% (HR: 1.2; 95% CI: 0.6 to 2.1; p = 0.62) for patency, and 14.4% and 12.4% (HR: 1.2; 95% CI: 0.5 to 2.8; p = 0.69) for target lesion revascularization. CONCLUSIONS: In the treatment of symptomatic femoropopliteal lesions, the Zilver PTX stent failed to show superiority over the Misago stent in freedom from ISR at 1 year.

Use of Numerical Simulation to Predict Iliac Complications During Placement of An Aortic Stent Graft.

BACKGROUND: During endovascular aneurysm repair (EVAR), complex iliac anatomy is a source of complications such as unintentional coverage of the hypogastric artery. The aim of our study was to evaluate ability to predict coverage of the hypogastric artery using a biomechanical model simulating arterial deformations caused by the delivery system. METHODS: The biomechanical model of deformation has been validated by many publications. The simulations were performed on 38 patients included retrospectively, for a total of 75 iliac arteries used for the study. On the basis of objective measurements, two groups were formed: one with "complex" iliac anatomy (n = 38 iliac arteries) and the other with "simple" iliac anatomy (n = 37 iliac arteries). The simulation enabled measurement of the lengths of the aorta and the iliac arteries once deformed by the device. Coverage of the hypogastric artery was predicted if the deformed renal/iliac bifurcation length (Lpre) was less than the length of the implanted device (Lstent-measured on the postoperative computed tomography [CT]) and nondeformed Lpre was greater than Lstent. RESULTS: Nine (12%) internal iliac arteries were covered unintentionally. Of the coverage attributed to perioperative deformations, 1 case (1.3%) occurred with simple anatomy and 6 (8.0%) with complex anatomy (P = 0.25). All cases of unintentional coverage were predicted by the simulation. The simulation predicted hypogastric coverage in 35 cases (46.7%). There were therefore 26 (34.6%) false positives. The simulation had a sensitivity of 100% and a specificity of 60.6%. On multivariate analysis, the factors significantly predictive of coverage were the iliac tortuosity index (P = 0.02) and the predicted margin between the termination of the graft limb and the origin of the hypogastric artery in nondeformed (P = 0.009) and deformed (P = 0.001) anatomy. CONCLUSIONS: Numerical simulation is a sensitive tool for predicting the risk of hypogastric coverage during EVAR and allows more precise preoperative sizing. Its specificity is liable to be improved by using a larger cohort.

Identification of Parameters Influencing the Vascular Structure Displacement in Fusion Imaging during Endovascular Aneurysm Repair.

PURPOSE: To quantify the displacement of the vascular structures after insertion of stiff devices during endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm and to identify potential parameters influencing this displacement. MATERIALS AND METHODS: A total of 50 patients from a single center undergoing EVAR were prospectively enrolled between January 2016 and December 2017. Fusion imaging was employed using the EndoNaut (Therenva, Rennnes, France) station through a 3-dimensional (3D)/2-dimensional (2D) technology synchronizing the 3D computed tomography scan to the live intraoperative fluoroscopy. The accuracy of the fusion roadmap was evaluated before deployment by conventional digital subtraction angiogram on a single plane (with different C-arm incidences). RESULTS: The mean displacement error of the ostium of the lowest renal artery was 4.1 ± 2.4 mm (range, 0-11.7 mm), with a left/right displacement of 1.6 ± 1.7 mm (range, 0-6.9 mm) and a craniocaudal displacement of 3.5 ± 2.4 mm (range, 0-11.3 mm). The correction required for the ostium of the lower renal artery was mostly cranial and to the left. Multiple linear regression analysis revealed only the sharpest angle between the aneurysm neck and sac as the factor influencing the accuracy of fusion imaging. All other parameters did not show any correlation. CONCLUSIONS: This study identified the sources of fusion error after insertion of rigid material during EVAR. As the sharpest angulation between aneurysm neck and sac increases, the overall accuracy of the fusion might be affected.