An Experimental Study of Laser in situ Fenestration of Current Aortic Endografts.

OBJECTIVE/BACKGROUND: Laser in situ fenestration (LISF) is emerging as an immediately available alternative in the endovascular treatment of complex aortic aneurysm. However, its biomechanical features remain poorly understood. The aim of this study was to experimentally evaluate textile damage secondary to LISF and to compare LISF with mechanical in situ fenestration (MISF). METHODS: An in vitro study evaluated the damage created by LISF on endograft fabrics versus MISF using a needle. Five different models of commercially available aortic endografts were used (32 samples of polyethylene terephthalate and expanded polytetrafluoroethylene fabrics). Tensile strength tests were performed on the fabrics before and after in situ fenestration, to determine the loss of mechanical strength. Integral water permeability tests at the stent-fenestration interface evaluated the watertightness of junctions. Stability of the connection was assessed with a fatigue bench test flexing the branch on the fenestration. In a second step, an in vivo study evaluating LISF in sheep was conducted. RESULTS: Resulting holes had circular and cauterised edges following LISF, whereas fabric filaments were pushed aside after MISF. Tensile tests demonstrated a 34% and a 27% mechanical resistance loss after LISF (p = .004) and MISF (p = .001) compared with non-fenestrated samples. A non-significant global decrease of 7% in mechanical resistance was found following LISF compared with MISF (p = .520). Water permeability tests highlighted that leak rates were higher following LISF than with MISF with regard to multifilament specimens (p < .05). Fatigue tests induced modification of the morphology of fenestrations. The surface area of the fenestration was increased for all samples after 170,000 cycles. Regarding the in vivo study, 14 LISF were performed in 12 sheep with a technical success rate of 88%. CONCLUSION: This study demonstrates that both LISF and MISF create substantial damage to all available endograft fabrics. Until comparisons with reinforced fenestrations are performed, LISF and MISF should not be used outside investigational studies.

Textile Aging Characterization on New Generations of Explanted Commercial Endoprostheses: A Preliminary Study.

OBJECTIVE/BACKGROUND: The goal of the present study was to assess the aging phenomena on second-generation textile endoprostheses (EPs) through explant analysis and to establish a preliminary classification of observed defects and material damages. METHODS: From January 2011 to June 2016 110 second- and recent-generation EPs were collected as a part of a European collaborative retrieval program. The analysis focused on the first 41 consecutive commercial EPs collected between 2011 and 2014 and made from polyethylene terephthalate. Explants were submitted to a standardized evaluation protocol, which included data recording, eye-naked evaluation, cleaning of organic remnants, and structural analysis under numerical optical microscopy. Observations were reported using a classification based on 15 features evaluating the fabric, the stitches between the fabric and the stents, and the stents. The total surface area of the holes within the fabric was measured. RESULTS: EPs were implanted for thoracic and abdominal procedures in 12 and 29 cases, respectively. The mean ± SD duration of implantation was 34 ± 26 months (range 2 days-8 years). Sixty-four percent of the samples demonstrated at least one defect caused by compression damage potentially related to the insertion of the EP within the delivery system, which promoted holes and tears. Ninety-five percent of all EPs demonstrated at least one type of abrasion on the stitches. The degradation of the stitches and the number of ruptures increased with duration of implantation. Stent degradation was rare and consisted of corrosion and rupture. Cumulated holed surface area increased with time and was measured up to 13.5 mm2. CONCLUSION: Various aging-related phenomena on commercial textile EPs were identified and classified. Main damaging mechanisms were related to compression and abrasion leading to tears and holes in the fabric and rupture of stitches.

Five Year Outcomes of Surgical Treatment for Popliteal Artery Entrapment Syndrome.

OBJECTIVE/BACKGROUND: The aim of this study was to evaluate long-term outcomes following surgery for popliteal artery entrapment syndrome. METHODS: A retrospective study of all patients that underwent surgery for popliteal artery entrapment syndrome between January 2003 and December 2009 was performed. Patient demographic data, clinical features, imaging modalities, and surgical management were recorded. The primary outcome was 5 year patency. RESULTS: Eighteen patients (25 limbs) underwent surgery. The mean age at the time of surgical procedure was 35 (median 35 years; range 15-49). Presentation was bilateral in seven patients (39%). Diagnosis was made using various imaging modalities, including position stress test, Duplex ultrasonography, computed tomography angiography, magnetic resonance imaging and conventional angiography. In four limbs the popliteal artery was compressed and undamaged (16%), and treatment consisted of musculo-tendinous division alone. In 16 limbs the popliteal artery was damaged with lesions limited to the popliteal artery (64%) where treatment consisted of venous interposition. In five limbs lesions extended beyond the popliteal artery (20%) and procedures included one below knee femoro-popliteal bypass, three femoro-posterior tibial bypasses, and one popliteo-posterior tibial bypass. Musculo-tendinous division was associated with vascular reconstruction in 19 limbs (90%). Mean follow up was 82 months (median 81 months, range 60-120). Five year patency was 84%. CONCLUSION: Long-term outcomes of surgical procedures performed for popliteal artery entrapment syndrome can be considered satisfactory.

Results of isolated infrapopliteal percutaneous transluminal angioplasty for critical limb ischemia in high-risk diabetic patients.

AIM: Infrapopliteal occlusive arterial lesions mostly characterize diabetic patients arteriopathy. Diabetic patients are prone to multiple comorbidities that make them candidates for low-invasive therapeutic options. The aim of this study was to evaluate the safety of infrapopliteal angioplasty in high-risk diabetic patients. METHODS: We undertook a study (retrospective study of a prospectively collected database) of all infrapopliteal endovascular revascularizations performed for critical limb ischemia in high-risk (≥3 major comorbidities) diabetic patients in our institution between 2008 and 2010. Study end points were safety, technical success rate, healing rate, overall 1-year survival, primary patency, secondary patency and limb salvage rates. RESULTS: A total of 101 high-risk diabetic patients (160 arterial lesions: 94 stenosis and 66 occlusions) underwent infrapopliteal endovascular surgery. No major adverse cardiovascular or cerebrovascular event was recorded within 30 days. Two major adverse limb events (two thromboses requiring major amputation) and seven minor adverse events were recorded. Technical and healing rates were, respectively, 83% and 78%. The 1-year survival, primary patency, secondary patency and limb salvage rates were, respectively, 86%, 67%, 83% and 84%. CONCLUSION: Infrapopliteal angioplasty can be considered as a safe and feasible option for high-risk diabetic patients with critical limb ischemia.

Chronic mesenteric ischemia: 20 year experience of open surgical treatment.

OBJECTIVES: Both open surgery (OS) and endovascular surgery (ES) have been proposed for the treatment of symptomatic chronic mesenteric ischaemia (CMI). OS was considered the gold standard but ES is increasingly proposed as the first option. The aim was to report long-term outcomes associated with OS in patients suffering CMI in the modern era in order to help in choose between the two techniques. MATERIALS AND METHODS: A retrospective single centre analysis of all consecutive digestive artery revascularizations performed for CMI between January 2003 and December 2012 was carried out. Primary outcomes were 30 day mortality and morbidity, and secondary outcomes were survival, primary patency (PP), secondary patency (SP), and freedom from digestive symptoms, depending on the completeness of the revascularization performed. RESULTS: Eighty-six revascularizations were performed. Median follow up was 6.9 years (range 0.3-20.0). The 30 day mortality and morbidity rates were respectively 3.5% and 13.9%. Ten year survival was 88% for complete revascularization (CR) and 76% for incomplete revascularization (IR) (p = .54). The PP was 84% at 10 years for CR and 87% respectively for IR (p = .51). The 10 year SP was 92% for CR and 93% for IR (p = .63). Freedom from digestive symptoms was influenced by the completeness of revascularization: 79% for CR versus 65% for IR at 10 years (p = .04). CONCLUSIONS: OS for CMI, especially complete revascularization, provides lasting results despite high morbidity.

Gender related Long-term Differences after Open Infrainguinal Surgery for Critical Limb Ischemia.

OBJECTIVE: The role of gender on long-term infrainguinal open surgery outcomes still remains uncertain in critical limb ischemia patients. The aim of this study is to evaluate the gender-specific differences in patient characteristics and long-term clinical outcomes in terms of survival, primary patency and limb salvage among patients undergoing infrainguinal open surgery for CLI. MATERIAL AND METHODS: All consecutive patients undergoing infrainguinal open surgery for critical limb ischemia between 2003 and 2012 were included. Survival, limb salvage and primary patency rates were assessed. Independent outcome determinants were identified by the Cox proportional hazard ratio using age and gender as adjustment factors. RESULTS: 584 patients (269 women and 315 men, mean age 76 and 71 years respectively) underwent 658 infrainguinal open surgery (313 in women and 345 in men). Survival rate at 6 years was lower among women compared to men with 53.5% vs 70.9% (p < 0.001). The same applied to primary patency (35.9% vs 52.4%, p < 0.001) and limb salvage (54.3% vs 81.1%, p < 0.001) at 6 years. Female-gender was an independent factor predicting death (hazard ratio 1.50), thrombosis (hazard ratio 2.37) and limb loss (hazard ratio 7.05) in age and gender-adjusted analysis. CONCLUSION: Gender-related disparity in critical limb ischemia open surgical revascularization outcomes still remains.

Compartmentalization of Inflammatory Response Following Gut Ischemia Reperfusion.

OBJECTIVE/BACKGROUND: Gut ischemia reperfusion (IR) is thought to trigger systemic inflammation, multiple organ failure, and death. The aim of this study was to investigate inflammatory responses in blood and in two target organs after gut IR. METHODS: This was a controlled animal study. Adult male Wistar rats were randomized into two groups of eight rats: control group and gut IR group (60 minutes of superior mesenteric artery occlusion followed by 60 minutes of reperfusion). Lactate and four cytokines (tumor necrosis factor-a, interleukin [IL]-1b, IL-6, and IL-10) were measured in mesenteric and systemic blood. The relative gene expression of these cytokines was determined by real time polymerase chain reaction in the gut, liver, and lung. RESULTS: Gut IR significantly increased lactate levels in mesenteric (0.9 ± 0.4 vs. 3.7 ± 1.8 mmol/L; p < .001) and in systemic blood (1.3 ± 0.2 vs. 4.0 ± 0.3 mmol/L; p < .001). Gut IR also increased the levels of four cytokines in mesenteric and systemic blood. IL-6 and IL-10 were the main circulating cytokines; there were no significant differences between mesenteric and systemic cytokine levels. IL-10 was upregulated mainly in the lung,suggesting that this organ could play a major role during gut reperfusion. CONCLUSION: The predominance of IL-10 over other cytokines in plasma and the dissimilar organ responses,especially of the lung, might be a basis for the design of therapies, for example lung protective ventilation strategies, to limit the deleterious effects of the inflammatory cascade. A multi-organ protective approach might involve gut directed therapies, protective ventilation, hemodynamic optimization, and hydric balance.

A new murine model of sustainable and durable chronic critical limb ischemia fairly mimicking human pathology.

OBJECTIVE: To establish a chronic mouse model of critical limb ischemia (CLI) with in vivo and ex vivo validation, closely mimicking human pathology. METHODS: Swiss mice (n = 28) were submitted to sequential unilateral femoral (day 0) and iliac (day 4) ligatures. Ischemia was confirmed by clinical scores (tissue and functional damages) and methoxyisobutylisonitrile (MIBI) scintigraphies at days 0, 4, 6, 10, 20, and 30. At days 10, 20, and 30, muscle mitochondrial respiration, calcium retention capacity (CRC), and production of reactive oxygen species (ROS) were investigated, together with transcripts of mitochondrial biogenesis and antioxidant enzymes. Histological analysis was also performed. RESULTS: Clinical and functional damage confirmed CLI. MIBI scintigraphies showed hypoperfusion of the ischemic limb, which remained stable until day 30. Mitochondrial respiration was impaired in ischemic muscles compared with controls (Vmax = 7.93 ± 0.99 vs. 10.09 ± 2.87 mmol/L O2/minute/mg dry weight [dw]; p = .01), together with impaired CRC (7.4 ± 1.6 mmol/L minute/mg dw vs. 11.9 ± 0.9 mmol/L minute/mg dw; p < .001) and biogenesis (41% decrease in peroxisome proliferator-activated receptor gamma coactivator [PGC]-1α, 49% decrease in PGC-1ß, and 41% decrease in nuclear respiratory factor-1). Ischemic muscles also demonstrated increased production of ROS under electron paramagnetic resonance (0.084 ± 0.029 vs. 0.051 ± 0.031 mmol/L minute/mg dw; p = .03) and with dihydroethidium staining (3622 ± 604 arbitrary units of fluorescence vs. 1224 ± 324; p < .01), decreased antioxidant enzymes (32% decrease in superoxide dismutase [SOD]1, 41% decrease in SOD2, and 49% decrease in catalase), and myopathic features (wider range in fiber size, rounded shape, centrally located nuclei, and smaller cross-sectional areas). All defects were stable over time. CONCLUSION: Sequential femoral and iliac ligatures closely mimic human functional, clinical, scintigraphic, and skeletal muscle mitochondrial characteristics, and could prove useful for testing therapeutic approaches.

Poor long-term stability of the Corvita abdominal stentgraft.

INTRODUCTION: The endovascular treatment of abdominal aortic aneurysms was introduced in the early 1990s, with different generations of devices using various options for either the stent skeleton or the membrane. REPORT: Corvita generated one of these devices using braided stainless steel and a porous spun polycarbonate urethane membrane. DISCUSSION: In this report, we describe a case involving Corvita stentgraft explantation for complete aneurysm reperfusion after 13 years, demonstrating major degradation of the polyurethane membrane.

Methylene blue protects liver oxidative capacity after gut ischaemia-reperfusion in the rat.

OBJECTIVES: Mesenteric ischaemia/reperfusion (IR) may lead to liver mitochondrial dysfunction and multiple organ failure. We determined whether gut IR induces early impairment of liver mitochondrial oxidative activity and whether methylene blue (MB) might afford protection. DESIGN: Controlled animal study. MATERIALS AND METHODS: Rats were randomised into three groups: controls (n = 18), gut IR group (mesenteric ischaemia (60 min)/reperfusion (60 min)) (n = 18) and gut IR + MB group (15 mg kg(-1) MB intra-peritoneally) (n = 16). Study parameters were: serum liver function markers, blood lactate, standard histology and DNA fragmentation (apoptosis) on intestinal and liver tissue, maximal oxidative capacity of liver mitochondria (state 3) and activity of complexes II, III and IV of the respiratory chain measured using a Clark oxygen electrode. RESULTS: Gut IR increased lactate deshydrogenase (+982%), aspartate and alanine aminotransferases (+43% and +74%, respectively) and lactate levels (+271%). It induced segmental loss of intestinal villi and cryptic apoptosis. It reduced liver state 3 respiration by 30% from 50.1 ± 3 to 35.2 ± 3.5 µM O(2) min(-1) g(-1) (P < 0.01) and the activity of complexes II, III and IV of the mitochondrial respiratory chain. Early impairment of liver mitochondrial respiration was related to blood lactate levels (r(2) = 0.45). MB restored liver mitochondrial function. CONCLUSIONS: MB protected against gut IR-induced liver mitochondria dysfunction.

[Assessment method of cognitive load and stress inducer factors of surgeons and anesthetists in the operating room]. / Méthodes d'évaluation de la charge cognitive et des facteurs inducteurs de stress des chirurgiens et anesthésistes au bloc opératoire.

INTRODUCTION: For many years, surgeons and anesthetists have recognized that stress can be present in their daily professional practice. The goal of this study was to identify tools for assessing stress and cognitive load in the operating room. MATERIAL AND METHODS: We conducted a literature review in the PubMed database of scientific articles published on the subject without date limit using the keywords anesthesia, surgery, surgeon, cognitive workload, definition, pathophysiology, physiological measurement, objective, subjective, stress. RESULTS: Nineteen articles were selected, focusing on cardiac surgery, gastrointestinal surgery, vascular surgery and urology. No publications concerning ophthalmology were found through the literature search. The means of measurement found were either subjective, such as questionnaires, or objective, such as the study of heart rate variability (HRV), reaction time, eye movements, electrical conductivity of the skin, biological markers and electroencephalogram. Of all these measurement tools, the NASA-TLX questionnaire, used in four articles, and the HRV study, used in eight articles, appear to be the most widely used and are strongly correlated with stress. CONCLUSION: The articles reviewed use only some of the available tools for assessment of stress and cognitive load. The main objective is to improve the quality of care and the quality of life of caregivers. It would be interesting to develop other methods to identify and better characterize the risk factors that increase stress and cognitive load.