Computational prediction of proximal sealing in endovascular abdominal aortic aneurysm repair with unfavorable necks.

BACKGROUND AND OBJECTIVE: Endovascular aortic aneurysm repair (EVAR) has become the standard treatment for abdominal aortic aneurysms in most centers. However, proximal sealing complications leading to endoleaks and migrations sometimes occur, particularly in unfavorable aortic anatomies and are strongly dependent on biomechanical interactions between the aortic wall and the endograft. The objective of the present work is to develop and validate a computational patient-specific model that can accurately predict these complications. METHODS: Based on pre-operative CT-scans, we developed finite element models of the aorta of 10 patients who underwent endovascular aortic aneurysm repair, 7 with standard morphologies and 3 with unfavorable anatomies. We simulated the deployment of stent grafts in each aorta by solving mechanical equilibrium with a virtual shell method. Eventually we compared the actual stent ring positions from post-operative computed-tomography-scans with the predicted simulated positions. RESULTS: A successful deployment simulation could be performed for each patient. Relative radial, transverse and longitudinal deviations were 6.3 ± 4.4%, 2.5 ± 0.9 mm and 1.4 ± 1.1 mm, respectively. CONCLUSIONS: The numerical model predicted accurately stent-graft positions in the aortic neck of 10 patients, even in complex anatomies. This shows the potential of computer simulation to anticipate possible proximal endoleak complications before EVAR interventions.

Lower-extremity arterial revascularization: Is there any evidence for diabetic foot ulcer-healing?

The presence of peripheral arterial disease (PAD) is an important consideration in the management of diabetic foot ulcers. Indeed, arteriopathy is a major factor in delayed healing and the increased risk of amputation. Revascularization is commonly performed in patients with critical limb ischaemia (CLI) and diabetic foot ulcer (DFU), but also in patients with less severe arteriopathy. The ulcer-healing rate obtained after revascularization ranges from 46% to 91% at 1 year and appears to be improved compared to patients without revascularization. However, in those studies, healing was often a secondary criterion, and there was no description of the initial wound or its management. Furthermore, specific alterations associated with diabetes, such as microcirculation disorders, abnormal angiogenesis and glycation of proteins, can alter healing and the benefits of revascularization. In this review, critical assessment of data from the literature was performed on the relationship between PAD, revascularization and healing of DFUs. Also, the impact of diabetes on the effectiveness of revascularization was analyzed and potential new therapeutic targets described.

Development of a smart guide wire using an electrostrictive polymer: option for steerable orientation and force feedback.

The development of steerable guide wire or catheter designs has been strongly limited by the lack of enabling actuator technologies. This paper presents the properties of an electrostrive actuator technology for steerable actuation. By carefully tailoring material properties and the actuator design, which can be integrated in devices, this technology should realistically make it possible to obtain a steerable guide wire design with considerable latitude. Electromechanical characteristics are described, and their impact on a steerable design is discussed.

Is naïveté forever? Alien predator and aggressor recognition by two endemic island reptiles.

The disproportionate impacts of invasive predators are often attributed to the naïveté (i.e., inefficient or non-existing anti-predator behavior) of island native species having evolved without such predators. Naïveté has long been regarded as a fixed characteristic, but a few recent studies indicate a capacity for behavioral adaptation in native species in contact with alien predators. Here, we tested whether two reptiles endemic to New Caledonia, a skink, Caledoniscincus austrocaledonicus, and a gecko, Bavayia septuiclavis, recognized and responded to the odor of six introduced species (two rodents, the feral cat, and three species of ants). We used an experimental design in which reptiles had a choice of retreat sites with or without the odor of predators or aggressors. Skinks avoided two or three of the predators, whereas geckos avoided at most one. These results suggest that diurnal skinks are more responsive than nocturnal geckos to the odor of introduced predators. Neither skinks nor geckos avoided the three species of ants. Thus, the odors of alien predators are shown to influence retreat site selection by two native island reptiles. Moreover, the study suggests that this loss of naïveté varies among native species, probably as a consequence of the intensity of the threat and of time since introduction. These findings argue for re-thinking the behavioral flexibility of ectothermic reptiles in terms of their responses to biological invasion.

Eumycetoma of the foot caused by Exophiala jeanselmei in a Guinean woman.

Eumycetomas are chronic infectious entities characterized by presence of mycotic grains in (sub-)cutaneous tissues, after accidental inoculation of an exogenous filamentous fungus in the skin. The lesions evolve towards painless pseudotumor of the soft parts. We report the original case of a Guinean woman exhibiting eumycetoma of the right foot. Both laboratory tests identified a dematiaceous fungus, Exophiala jeanselmei, as the responsible infectious agent. A medical treatment with voriconazole alone was sufficient to notice a substantial clinical improvement. This finding is unusual as E. jeanselmei is uncommon in Guinea-Conakry, and as optimal treatment rather associate antifungal azoles and surgical excision.

Monitoring plaque inflammation in atherosclerotic rabbits with an iron oxide (P904) and (18)F-FDG using a combined PET/MR scanner.

PURPOSE: The aim of this study was to compare the ability of (18)F-FDG PET and iron contrast-enhanced MRI with a novel USPIO (P904) to assess change in plaque inflammation induced by atorvastatin and dietary change in a rabbit model of atherosclerosis using a combined PET/MR scanner. MATERIALS AND METHODS: Atherosclerotic rabbits underwent USPIO-enhanced MRI and (18)F-FDG PET in PET/MR hybrid system at baseline and were then randomly divided into a progression group (high cholesterol diet) and a regression group (chow diet and atorvastatin). Each group was scanned again 6 months after baseline imaging. R2* (i.e. 1/T2*) values were calculated pre/post P904 injection. (18)F-FDG PET data were analyzed by averaging the mean Standard Uptake Value (SUVmean) over the abdominal aorta. The in vivo imaging was then correlated with matched histological sections stained for macrophages. RESULTS: (18)F-FDG PET showed strong FDG uptake in the abdominal aorta and P904 injection revealed an increase in R2* values in the aortic wall at baseline. At 6 months, SUVmean values measured in the regression group showed a significant decrease from baseline (p = 0.015). In comparison, progression group values remained constant (p = 0.681). R2* values showed a similar decreasing trend in the regression group suggesting less USPIO uptake in the aortic wall. Correlations between SUVmean or Change in R2* value and macrophages density (RAM-11 staining) were good (R(2) = 0.778 and 0.707 respectively). CONCLUSION: This experimental study confirms the possibility to combine two functional imaging modalities to assess changes in the inflammation of atherosclerotic plaques. (18)F-FDG-PET seems to be more sensitive than USPIO P904 to detect early changes in plaque inflammation.

Midterm outcomes of embolisation of internal iliac artery aneurysms.

OBJECTIVES: There is no standardised technique for internal iliac artery aneurysm (IIAA) embolisation and results of long-term prevention of rupture are unknown. DESIGN: We retrospectively evaluated technical aspects and results of IIAA embolisation in a multicentre study. METHODS: Aneurysm morphology and embolisation techniques were reviewed. Aneurysm-related death, rupture, diameter increase, endoleak, secondary procedure and complication related to the IIA occlusion were recorded. RESULTS: Between 2001 and 2011, 53 patients with 57 IIAA were treated. Mean diameter of IIAA was 41 mm (range: 25-88 mm). Embolisation techniques were distal and proximal occlusion (n = 24), proximal occlusion (n = 18) and sac packing (n = 15). Cumulative overall survival rate was 92% at 1 year, 83% at 3 years and 59% at 5 years. No cause of deaths was related to aneurysm. Aneurysm diameter increased in five patients and endoleak was observed in 11 patients. One secondary open conversion and five secondary endovascular procedures were performed for increase of diameter or proximal endoleak. Two patients experienced a disabling buttock claudication. CONCLUSIONS: Embolisation of IIAA is safe in the short- and midterm. However, endoleak and aneurysm diameter increases are not rare. Yearly post-procedure computed tomography angiography seems appropriate.

Pulsed resources affect the timing of first breeding and lifetime reproductive success of tawny owls.

1. According to life-history theory, environmental variability and costs of reproduction account for the prevalence of delayed reproduction in many taxa. Empirical estimates of the fitness consequences of different ages at first breeding in a variable environment are few however such that the contributions of environmental and individual variability remains poorly known. 2. Our objectives were to elucidate processes that underpin variation in delayed reproduction and to assess lifetime consequences of the age of first breeding in a site-faithful predator, the tawny owl Strix aluco L. subjected to fluctuating selection linked to cyclical variation in vole density (typically 3-year cycles with low, increasing and decreasing vole densities in successive years). 3. A multistate capture-recapture model revealed that owl cohorts had strikingly different juvenile survival prospects, with estimates ranging from 0.08 to 0.33 respectively for birds born in Decrease and Increase phases of the vole cycle. This resulted in a highly skewed population structure with >75% of local recruits being reared during Increase years. In contrast, adult survival remained constant throughout a vole cycle. The probability of commencing reproduction was lower at age 1 than at older ages, and especially so for females. From age 2 onwards, pre-breeders had high probabilities of entering the breeding population. 4. Variation in lifetime reproductive success was driven by the phase of the vole cycle in which female owls started their breeding career (26-47% of variance explained, whether based on the number of local recruits or fledglings), more than by age at first breeding or by conditions experienced at birth. Females who postponed reproduction to breed for the first time at age 3 during an Increase phase, produced more recruits, even when accounting for birds that may have died before reproduction. No such effects were detected for males. 5. Sex-specific costs of early reproduction may have accounted for females being more prone to delay reproduction. Contrary to expectations from a best-of-a-bad job strategy, early-hatched, hence potentially higher-quality females were more likely to breed at age 1, but then experienced rapidly declining food resources and so seemed caught in a life-history trap set by the multiannual vole cycle.

Conversion to open repair after endovascular aneurysm repair: causes and results. A French multicentric study.

OBJECTIVE: To evaluate the causes and results of conversion to open repair after aortic aneurysm endovascular treatment (EVAR). DESIGN: Retrospective study of open conversion after EVAR was performed in eight French academic centres. Primary conversion (PC) within 30 days after EVAR and secondary conversions (SC) were analysed separately. RESULT: Between 1997 and 2007, open conversions were performed in 34 patients (most often in high-risk patients): 14 PC and 20 SC. Two main causes of PC were unfavourable iliac artery anatomy and renal artery coverage. In hospital mortality was 21%. SC occurred at a median of 44 months after primary EVAR. Nine were urgent cases for rupture or infection and 11 elective for aneurysm growth, infection or thrombosis. Early mortality was similar after emergent or elective SC (25%). CONCLUSION: Open conversion, and, in particular, PC and urgent SC, was associated with a poor outcome. According to the literature, mortality after elective SC is low but remains high in high-risk patients.

Evaluation of a new vascular suture system for aortic laparoscopic surgery: an experimental study on pigs and cadavers.

OBJECTIVES: The aim of this study was to assess the feasibility and efficacy of a new laparoscopic vascular suturing device. METHODS: Animal study: six pigs underwent surgery using a retroperitoneal laparoscopic approach. Aorto-prosthetic side-to-end and end-to-end anastomoses were performed laparoscopically on each pig using SuDyn. Clamping and anastomosis times, as well as the properties of the anastomoses, were recorded. Study on cadavers: four aorto-prosthetic end-to-end anastomoses were performed using the direct transperitoneal laparoscopic approach to assess the feasibility of the SuDyn device on atherosclerotic aortas. RESULTS: Animal study: No pigs died and 12 patent and impermeable anastomoses were obtained. Mean anastomosis time was 38(+/-8)min for end-to-side anastomoses and 37(+/-5)min for end-to-end anastomoses. Study on cadavers: Totally laparoscopic anastomoses were performed in 4 human cadavers with a mean anastomosis time of 37(+/-3)min. CONCLUSIONS: SuDyn makes laparoscopic aorto-prosthetic anastomoses easier to perform, produces good results and does not require a learning curve.

[Exercise-induced dyspnea and hilar enlargement]. / Dyspnée d'effort et gros hiles.

We report the case of a 46-year-old man with an uneventful history who was hospitalized for suspected pulmonary embolism. The chest x-ray did not reveal any parenchymatous anomaly but disclosed pseudo-tumoral enlargement of the pulmonary arteries. There was no right ventricular overload at cardiac echography and the pulmonary arterial pressure was normal. Helicoidal angioscan demonstrated aneurismal dilatation of the both pulmonary arteries, complicated by a thrombus on the right. Outcome was favorable with anticoagulation. After ruling out acquired aneurysm, the diagnosis retained was idiopathic aneurysm of the pulmonary arteries.

[Appendicectomy in the tropics: prospective study at Hôpital Principal in Dakar]. / Appendicectomies en milieu tropical: étude prospective à l'Hôpital Principal de Dakar.

Acute appendicitis is the most common surgical indication in Africa. It is associated with higher mortality and morbidity than in industrialized countries. The purpose of this prospective 100 case study was to evaluate diagnostic, clinical and paraclinical features as well as surgical modalities especially with regard to approach and postoperative recovery in patients that underwent surgical treatment for appendicitic syndromes over a 9-month period at our institution. Analysis of study data confirmed that surgical indications could be established based on clinical examination alone and that adjuvant investigations only delayed therapy while providing little specific, useful information. Delayed management is a specific feature of tropical areas. Surgical exposure was achieved by the MacBurney approach in 65% of cases, celioscopic approach in 18%, and median laparotomy in 17%. The benefit of the celiosocopic approach was statistically signicant in terms of resumption of eating, duration of hospitalization and incidence of postoperative complications. Mortality in this series was 0% and morbidity was 7% mainly due to parietal complications.

[Transient intestinal pseudo-obstruction syndrome in premature infants]. / Le syndrome de pseudo-obstruction intestinale transitoire du prématuré.

BACKGROUND: A chronic intestinal pseudo-obstruction is sometimes seen in premature neonates who are fed early and subsequently suffer from digestive intolerance for several weeks. PATIENTS: Seven premature babies (mean gestational age: 30.5 weeks, mean birthweight: 950 g) suffered from abdominal distension and failure to pass stools at a mean age of 2.5 days (extremes: 1 to 6 days); 2 of them also had vomiting. X-ray examination showed dilated loops of bowel throughout the abdomen without obstructive changes; barium or Gastrografin studies demonstrated inertia of the colon without obstructive changes or abrupt changes in caliber. Histological examination of enteric nerve cells in 2 cases showed normal maturation. Parenteral nutrition was necessary in all patients for 30 to 78 days (mean: 47), followed by continuous enteral feeding for 24 to 48 days (mean: 37). Septicemia complicated parenteral nutrition in 4 babies and was responsible for the death of 1 of them. Normal evacuation of stools occurred between day 27 and day 91 (mean day 46) allowing normal enteral feeding. All 6 patients, now aged 2.5 to 8 years (mean 3.5 years) are in good health, and have no digestive problems. CONCLUSIONS: Immaturity of intestinal motility may occur in some premature neonates suffering from intestinal ileus. Parenteral nutrition may be necessary for several weeks, but spontaneous recovery is usual. This transient intestinal pseudo-obstruction of premature babies is different from the classical chronic pseudo-obstruction for which surgery is often needed.