Patrick Lermusiaux

Fenestrated Endovascular Grafting: The French Multicentre Experience

PURPOSE This study aims to evaluate the medium-term outcomes following aortic aneurysm repair using fenestrated endografts performed in 16 French academic centres. MATERIALS AND METHODS A retrospective analysis of prospectively collected data was carried out. This study included all patients treated with fenestrated endografts in France between May 2004 and January 2009. Patients were judged to be at high risk for open surgical repair. Fenestrated endografts were designed using computed tomography (CT) reconstructions performed on three-dimensional (3D) workstations. All patients were evaluated with CT, duplex ultrasound and plain film radiograph at discharge, 6, 12, 18 and 24 months, and annually thereafter. RESULTS A total of 134 patients (129 males) were treated over the study period. Median age and aneurysm size were 73 years (range 48-91 years) and 56 mm (range 45-91 mm), respectively. A total of 403 visceral vessels were perfused through a fabric fenestration, including 265 renal arteries. One early conversion to open surgery was required. Completion angiography and discharge CT scan showed that 398/403 (99%) and 389/394 (99%) respective target vessels were patent. The 30-day mortality rate was 2% (3/134). Pre-discharge imaging identified 16 (12%) endoleaks: three type I, 12 type II and one type III. After the procedure, transient or permanent dialysis was required in four (3%) and two (1%) patients, respectively. The median duration of follow-up was 15 months (range 2-53 months). No aneurysms ruptured or required open conversion during the follow-up period. Twelve of 131 patients (9%) died during follow-up (actuarial survival at 12 and 24 months: 93% and 86%, respectively). Median time from procedure to death was 15 months. None of these deaths were aneurysm related. Aneurysm sac size decreased by more than 5 mm in 52%, 65.6% and 75% of patients at 1, 2 and 3 years, respectively. Three (4%) patients had sac enlargement within the first year, associated with a persistent endoleak. During follow-up, four renal artery occlusions were detected. A total of 12 procedure-related re-interventions were performed in 12 patients during follow-up, including six to correct endoleaks, and five to correct threatened visceral vessels. CONCLUSIONS The use of endovascular prostheses with graft material incorporating the visceral arteries is safe and effective in preventing rupture in the medium term. A predictable high mortality rate was depicted during follow-up in this high-risk cohort. Meticulous follow-up to assess sac behaviour and visceral ostia is critical to ensure optimal results.

An Analysis of the French Multicentre Experience of Fenestrated Aortic Endografts: Medium-Term Outcomes

Purpose:To evaluate the medium-term outcomes following aortic aneurysm repair utilizing fenestrated endografts performed in 13 French academic centers. Materials and Methods:A retrospective analysis of prospectively collected data. All patients had asymptomatic aneurysms involving or close to the visceral-bearing abdominal aorta and were judged to be at high-risk for open surgical repair. Fenestrated endografts were designed using computed tomography reconstructions performed on three-dimensional workstations. The procedures were conducted under fluoroscopic control by experienced endovascular teams. All patients were evaluated with computed tomography, duplex ultrasound, and plain film radiograph at discharge, 6, 12, 18, and 24 months, and annually thereafter. Results:Eighty patients (78 males) were treated over 44 months (May 2004–January 2008). Median age and aneurysm size were 78 years (range: 48–90 years) and 59 mm (range: 47–82 mm), respectively. A total of 237 visceral vessels were perfused through a fabric fenestration (median of 3 per patient). One early conversion to open surgery was required. Completion angiography showed that 234 of 237 (99%) target vessels were patent. Two patients (2.5%) died within 30 days of device implantation. Predischarge imaging identified 9 (11%) endoleaks: 3 type I, 5 type II, and 1 type III. The median duration of follow-up was 10 months (range: 1–38 months). No aneurysms ruptured or required open conversion during the follow-up period. Four of 78 (5%) died during follow-up (actuarial survival at 24 months 92%), none of these deaths were aneurysm related. Aneurysm sac size decreased by more than 5 mm in 33%, 53%, and 58% at 6, 12, and 18 months, respectively. One patient had sac enlargement within the first year, associated with a persistent type II endoleak. In-stent stenoses or occlusion affected 4 renal arteries. Secondary procedures were performed in 8 patients (10%) during follow-up, 5 to correct endoleaks and 3 to correct threatened visceral vessels. Conclusions:The use of endovascular prostheses with graft material incorporating the visceral arteries is safe in high risk patients with high risk aneurysms. In the medium-term it is effective in preventing rupture. However, meticulous follow-up to assess sac behavior and visceral ostia is critical to ensure optimal results.

Angioplasty of the Common Femoral Artery and Its Bifurcation

BACKGROUND To evaluate the efficacy of percutaneous transluminal angioplasty (PTA) of atherosclerotic lesions of the common femoral artery (CFA) and its bifurcation. METHODS From 2009 to 2013, 53 patients (43 men, average age, 68 years) were included in a single-center, nonrandomized, prospective study. Indication was disabling intermittent claudication (n = 36) or chronic critical limb ischemia (n = 17). Thirty-four procedures (64%) were isolated CFA PTA, whereas 7 of 53 (13%) involved inflow (including 4 iliac occlusions) and 12 of 53 (23%) involved outflow vessels. Primary stenting was performed in 50 cases (95%). CFA occlusions were recanalized in 4 of 53. Lesions involved the bifurcation in 22 cases (40%). Follow-up consisted of clinical examination and duplex scanning with ankle-brachial index measurement at 1, 6, and 12 months. A biplane X-ray was performed at 1 year. The primary end point was the absence of binary restenosis (>50% reobstruction of the CFA). Secondary end points were freedom from target lesion revascularization (TLR) and stent fracture rate. RESULTS Procedural success was achieved in 96% of cases. At a mean follow-up of 24 months (with 1 patient lost of follow-up), the absence of binary restenosis was 92.5%. At the end of follow-up, 82% of patients continued to show clinical improvement. Freedom from TLR was 97%. Stent fracture rate at 1 year was 9%. CONCLUSIONS PTA of the CFA and its bifurcation is a reliable technique with good midterm functional results. These results justify performing a randomized study comparing surgery and endovascular treatment.

Comparison between a generalized Newtonian model and a network-type multiscale model for hemodynamic behavior in the aortic arch: Validation with 4D MRI data for a case study

Blood is a complex fluid in which the presence of the various constituents leads to significant changes in its rheological properties. Thus, an appropriate non-Newtonian model is advisable; and we choose a Modified version of the rheological model of Phan-Thien and Tanner (MPTT). The different parameters of this model, derived from the rheology of polymers, allow characterization of the non-Newtonian nature of blood, taking into account the behavior of red blood cells in plasma. Using the MPTT model that we implemented in the open access software OpenFOAM, numerical simulations have been performed on blood flow in the thoracic aorta for a healthy patient. We started from a patient-specific model which was constructed from medical images. Exiting flow boundary conditions have been developped, based on a 3-element Windkessel model to approximate physiological conditions. The parameters of the Windkessel model were calibrated with in vivo measurements of flow rate and pressure. The influence of the selected viscosity of red blood cells on the flow and wall shear stress (WSS) was investigated. Results obtained from this model were compared to those of the Newtonian model, and to those of a generalized Newtonian model, as well as to in vivo dynamic data from 4D MRI during a cardiac cycle. Upon evaluating the results, the MPTT model shows better agreement with the MRI data during the systolic and diastolic phases than the Newtonian or generalized Newtonian model, which confirms our interest in using a complex viscoelastic model.

A New Hemodynamic Ex Vivo Model for Medical Devices Assessment

BACKGROUND In-stent restenosis (ISR) remains a major public health concern associated with an increased morbidity, mortality, and health-related costs. Drug-eluting stents (DES) have reduced ISR, but generate healing-related issues or hypersensitivity reactions, leading to an increased risk of late acute stent thrombosis. Assessments of new DES are based on animal models or in vitro release systems, which have several limitations. The role of flow and shear stress on endothelial cell and ISR has also been emphasized. The aim of this work was to design and first evaluate an original bioreactor, replicating ex vivo hemodynamic and biological conditions similar to human conditions, to further evaluate new DES. METHODS This bioreactor was designed to study up to 6 stented arteries connected in bypass, immersed in a culture box, in which circulated a physiological systolo-diastolic resistive flow. Two centrifugal pumps drove the flow. The main pump generated pulsating flows by modulation of rotation velocity, and the second pump worked at constant rotation velocity, ensuring the counter pressure levels and backflows. The flow rate, the velocity profile, the arterial pressure, and the resistance of the flow were adjustable. The bioreactor was placed in an incubator to reproduce a biological environment. RESULTS A first feasibility experience was performed over a 24-day period. Three rat aortic thoracic arteries were placed into the bioreactor, immersed in cell culture medium changed every 3 days, and with a circulating systolic and diastolic flux during the entire experimentation. There was no infection and no leak. At the end of the experimentation, a morphometric analysis was performed confirming the viability of the arteries. CONCLUSIONS We designed and patented an original hemodynamic ex vivo model to further study new DES, as well as a wide range of vascular diseases and medical devices. This bioreactor will allow characterization of the velocity field and drug transfers within a stented artery with new functionalized DES, with experimental means not available in vivo. Another major benefit will be the reduction of animal experimentation and the opportunity to test new DES or other vascular therapeutics in human tissues (human infrapopliteal or coronary arteries collected during human donation).