Bioadhesive Perivascular Microparticle-Gel Drug Delivery System for Intimal Hyperplasia Prevention: In Vitro Evaluation and Preliminary Biocompatibility Assessment.

Intimal hyperplasia (IH) is an undesirable pathology occurring after peripheral or coronary bypass surgery. It involves the proliferation and migration of vascular smooth muscle cells, leading to a reduction in the diameter of the vascular lumen, which can lead to stenosis and graft failure. Topically applied atorvastatin (ATV) has been shown to slow down this process. To be effective, the drug delivery system should remain at the perivascular site for 5-8 weeks, corresponding to the progression of IH, and be capable of releasing an initial dose of the drug followed by a sustained release. Ideally, bioadhesion would anchor the gel to the application site. To meet these needs, we encapsulated ATV in a 2-component system: a hyaluronic acid-dopamine bioadhesive gel for rapid release and biodegradable microparticles for sustained release. The system was characterized by scanning electron microscopy, rheology, bioadhesion on porcine arteries, and a release profile. The rheological properties were adequate for perivascular application, and we demonstrated superior bioadhesion and cohesion compared to the control HA formulations. The release profile showed a burst, generated by free ATV, followed by sustained release over 8 weeks. A preliminary evaluation of subcutaneous biocompatibility in rats showed good tolerance of the gel. These results offer new perspectives on the perivascular application towards an effective solution for the prevention of IH.

Ten Year Experience of Using Cryopreserved Arterial Allografts for Distal Bypass in Critical Limb Ischaemia.

OBJECTIVE/BACKGROUND: In critical limb ischaemia (CLI), current guidelines recommend revascularisation whenever possible, preferentially through endovascular means. However, in the case of long occlusions or failed endovascular attempts, distal bypasses still have a place. Single segment great saphenous vein (GSV), which provides the best conduit, is often not available and currently there is no consensus about the best alternative graft. METHODS: From January 2006 to December 2015, 42 cryopreserved arterial allografts were used for a distal bypass. Autologous GSVs or alternative autologous conduits were unavailable for all patients. The patients were observed for survival, limb salvage, and allograft patency. The results were analysed with Kaplan-Meier graphs. RESULTS: Estimates of secondary patency at one, two and five years were 81%, 73%, and 57%, respectively. Estimates of primary patency rates at one, two and five years were 60%, 56%, and 26%, respectively. Estimates of limb salvage rates at one, two and five years were 89%, 89%, and 82%, respectively. Estimates of survival rates at one, two and five years were 92%, 76% and 34%, respectively. At 30 days, major amputations and major adverse cardiac events were one and zero, respectively. Six major amputations occurred during the long-term follow up. CONCLUSION: Despite a low primary patency rate at two years, the secondary patency of arterial allografts is acceptable for distal bypasses. This suggests that cryopreserved arterial allografts are a suitable alternative for limb saving distal bypasses in the absence of venous conduits, improving limb salvage rates and, possibly, quality of life.

Evaluating intimal hyperplasia under clinical conditions.

OBJECTIVES: Open arterial revascularization using venous segments is frequently associated with the development of intimal hyperplasia (IH), leading to severe restenosis and graft failure. The lack of treatment to prevent this pathology is a major problem. Therefore, we generated a new porcine model, which closely mimics the clinical development of human IH, to test the therapeutic potential of candidate drugs. METHODS: A patch of jugular vein was sutured to the right common carotid artery of pigs, to expose the vein to haemodynamic conditions of the arterial bed. Four weeks after surgery, the operated vessels which received no further treatment (the control group) were compared with (i) contralateral, non-operated vessels (the healthy group); (ii) vessels of pigs that received a perivascular application of a drug-free microparticle gel (the placebo group) and (iii) vessels of pigs that perioperatively received the same gel loaded with 10-mg atorvastatin (the atorvastatin group). RESULTS: When compared with non-operated vessels, all operated segments displayed a sizable IH which was thicker in the venous patch than in the host artery. These alterations were associated with a thickening of the intima layer of both vessels in the absence of inflammation. The intima/media ratio has been significantly increased by 2000-fold in the vein patches. Perivascular application of atorvastatin did not prevent IH formation. However, the drug increased the adventitial neovascularization in the operated vessels. CONCLUSIONS: The novel porcine model allows for monitoring IH formation under haemodynamic conditions which mimic clinical situations. It should facilitate the screening of innovative treatments to prevent restenosis.

Who Should Be Operated When Presenting with a Ruptured Abdominal Aortic Aneurysm? A Monocentric Study in a Tertiary Hospital.

BACKGROUND: Mortality with ruptured abdominal aortic aneurysms (rAAAs) is 80% overall, 50% when operated, and 100% when not operated. Distinguishing in emergency patients who should be operated versus being offered palliative treatment is difficult. We sought to identify key factors to consider in this decision-making. METHODS: Between 2001 and 2014, we selected all consecutive patients with rAAA treated by open or endovascular procedures in a tertiary hospital for inclusion in this retrospective, single-center study. Symptomatic aneurysms and isolated ruptured iliac aneurysms were excluded. The primary outcome was in-hospital mortality, and secondary outcomes were institutionalization rate and long-term mortality. Associations between predictive factors and in-hospital mortality were evaluated using univariate logistic regression. The local ethics committee approved this study. RESULTS: The mean age (±standard deviation) of the 72 included patients was 73 years (±9.0) and 88% were men. Among the 65 open (90%) and 7 endovascular procedures (10%), overall in-hospital mortality was 21%, 1- and 2-year mortalities were both 26%, and the institutionalization rate was 5%. Mean follow-up was 43 months (Kaplan-Meier estimate). Univariate analysis identified age as associated with a 20% per year increased risk of in-hospital mortality (correlation, P < 0.0001). Female sex was the other main preoperative risk factor correlated with in-hospital mortality (P = 0.006). Significant perioperative risk factors were suprarenal clamping (P = 0.038), amount of fresh frozen plasma transfused (P = 0.018), and number of blood transfusions (P < 0.0001). CONCLUSIONS: The most significant preoperative mortality-related factors were age and female sex. Our study also showed that institutionalization and long-term mortality are not factors to consider in the decision-making process.

[Rare vascular diseases, building dedicated multidisciplinary specialized center]. / Maladies vasculaires rares, mise en place d'un centre multidisciplinaire spécialisé au CHUV.

Rare Vascular Diseases (RVD) encompass different types of vessel involvement. Some cause a dilation, others a weakening or tortuosity of the arterial wall, others an obstruction or excessive calcification of arterial walls. Clinical pathway of patients with RVD to diagnosis is often long and complex. Thus, in order to allow early diagnosis and coordinated multidisciplinary management and follow-up, a specialized RVD centre has been set-up at the CHUV, following the framework of the national concept of rare diseases.

Les maladies vasculaires rares (MVR) englobent différents types d'atteintes des vaisseaux. Certaines engendrent une dilatation ou une tortuosité de la paroi artérielle, d'autres une fragilisation de la paroi, d'autres encore entraînent une obstruction du vaisseau, une calcification excessive des parois, ou des malformations vasculaires. Comme pour toutes les maladies rares, le parcours des patients vers un diagnostic est souvent long et complexe. Afin de permettre un diagnostic le plus précoce possible, ainsi qu'un suivi coordonné et une prise en charge multidisciplinaire médicale et sociale, un centre des MVR a été mis en place au CHUV, dans le cadre du concept national des maladies rares.

Perivascular medical devices and drug delivery systems: Making the right choices.

Perivascular medical devices and perivascular drug delivery systems are conceived for local application around a blood vessel during open vascular surgery. These systems provide mechanical support and/or pharmacological activity for the prevention of intimal hyperplasia following vessel injury. Despite abundant reports in the literature and numerous clinical trials, no efficient perivascular treatment is available. In this review, the existing perivascular medical devices and perivascular drug delivery systems, such as polymeric gels, meshes, sheaths, wraps, matrices, and metal meshes, are jointly evaluated. The key criteria for the design of an ideal perivascular system are identified. Perivascular treatments should have mechanical specifications that ensure system localization, prolonged retention and adequate vascular constriction. From the data gathered, it appears that a drug is necessary to increase the efficacy of these systems. As such, the release kinetics of pharmacological agents should match the development of the pathology. A successful perivascular system must combine these optimized pharmacological and mechanical properties to be efficient.

Zenith Bifurcated Iliac Side Branch Device: Mid-term Results and Assessment of Risk Factors for Intraoperative Thrombosis.

BACKGROUND: The aim of this study is to evaluate the short- and mid-term results of the Zenith bifurcated iliac side branch device (ZBIS) in the treatment of common iliac artery (CIA) aneurysms, and to assess risk factors for intraoperative internal iliac artery (IIA) thrombosis. METHODS: All patients who underwent endovascular treatment of either an isolated CIA aneurysm or an aortoiliac aneurysm using the ZBIS device in the departments of vascular surgery of Strasbourg (France) and Lausanne (Switzerland) between January 2010 and December 2014 were retrospectively collected. RESULTS: Thirty-one implantations were performed: 30 patients underwent 31 endovascular CIA aneurysm treatments with the ZBIS device. Mean operative time was 188 min. Technical success was obtained in 26 implantations (84%). In 5 implantations (16%), the final angiogram revealed an IIA thrombosis. Thirty-day mortality was 3.2%. Thirty-day morbidity was 13.3%. Mean follow-up was 15 months. Overall survival was 96% at 1 year and 89% at 2 years. In intention-to-treat analysis, primary patency of the internal iliac side branch was 84% at 1 year and 76% at 2 years (5 peroperative IIA occlusions and 1 late occlusion). Freedom from reintervention was 89% at 1 and 2 years. One case of type III endoleak and 2 cases of type II endoleaks were identified. Only type III endoleak required an additional intervention with a covered stent. Aneurysm diameter decreased in 15 implantations (48%) and remained stable in 16 implantations (52%). Clinical, radiological, and peroperative parameters were analyzed to identify risk factor for intraoperative thrombosis of the internal iliac side branch. Notion of intraoperative difficulties (any additional procedure that was not initially planned and increasing the operating time) appeared as a risk factor in multivariate analysis (P < 0.01, standard deviation 1.27, odds ratio 30.6). CONCLUSIONS: The main findings of our study is that the procedure can be difficult to perform in particular conditions and can lead to peroperative failure in these cases, highlighting the need for adequate patients screening. When technical success is obtained, outcomes can be considered as satisfactory.

[Sarcoma centres : a necessary tool in the management of patients and for research.] / Centre des sarcomes : un nouvel outil pour améliorer la prise en charge du patient et soutenir la recherche.

Sarcomas are rare diseases, the treatment of which requires an appropriate technical plateform and a broad spectrum of multidisciplinary specialists. Many are initially treated by unplanned excision, and then referred to specialized centres. Secondary treatments may lead to higher complication rates and local recurrence, with lower functional outcome, life quality and possibly overall survival. In order to improve the accessibility for referral to a specialist centre, the coordination of clinical and research activities, and the quality of the management of sarcomas in general, Lausanne University Hospital (CHUV) has opened a Sarcoma centre on October 1st 2016. The objective of the present paper is to illustrate the concept and provide useful clinical recommendations.

Les sarcomes sont des maladies rares, dont la prise en charge multidisciplinaire nécessite un plateau technique important. Ils font souvent l'objet d'une excision initiale accidentelle, nécessitant une reprise en milieu spécialisé, avec un risque majoré de complications et de récidive locale, un impact sur la fonction, voire la survie. La prise en charge des sarcomes est réservée aux centres de référence, où il est souvent difficile pour le praticien de trouver un interlocuteur à qui adresser un patient ou demander un avis. Pour les cliniciens et les chercheurs, il est souvent compliqué de coordonner les activités. Pour en améliorer la prise en charge globale, le CHUV a donc créé un centre des sarcomes, inauguré le 1er octobre 2016. Le présent article a pour but d'illustrer cette problématique et de rappeler quelques données cliniques utiles.

Endovascular Versus Open Abdominal Aortic Aneurysm: Best Decision.

Since the first implantation of an endograft in 1991, endovascular aneurysm repair (EVAR) rapidly gained recognition. Historical trials showed lower early mortality rates but these results were not maintained beyond 4 years. Despite newer-generation devices, higher rates of reintervention are associated with EVAR during follow-up. Therefore, the best therapeutic decision relies on many parameters that the physician has to take in consideration. Patient's preferences and characteristics are important, especially age and life expectancy besides health status. Aneurysmal anatomical conditions remain probably the most predictive factor that should be carefully evaluated to offer the best treatment. Unfavorable anatomy has been observed to be associated with more complications especially endoleak, leading to more re-interventions and higher risk of late mortality. Nevertheless, technological advances have made surgeons move forward beyond the set barriers. Thus, more endografts are implanted outside the instructions for use despite excellent results after open repair especially in low-risk patients. When debating about AAA repair, some other crucial points should be analysed. It has been shown that strict surveillance is mandatory after EVAR to offer durable results and prevent late rupture. Such program is associated with additional costs and with increased risk of radiation. Moreover, a risk of loss of renal function exists when repetitive imaging and secondary procedures are required. The aim of this article is to review the data associated with abdominal aortic aneurysm and its treatment in order to establish selection criteria to decide between open or endovascular repair.

Abdominal Aortic Aneurysm: What About Screening?

The prevalence of abdominal aortic aneurysm (AAA) in general population is 4-9% with a high mortality rate when ruptured. Therefore, screening programs were developed in many countries to detect small and large AAA in selected patients. Indeed, prevalence of AAA increases in patients over 65 years old with cigarette smoking history. This paper reviews recent literature related to AAA screening focusing on epidemiology, screening tests and evidence based medicine to highlight not only advantages but also disadvantages of screening programs among population.

The use of external mesh reinforcement to reduce intimal hyperplasia and preserve the structure of human saphenous veins.

The saphenous vein is the conduit of choice in bypass graft procedures. Haemodynamic factors play a major role in the development of intimal hyperplasia (IH), and subsequent bypass failure. To evaluate the potential protective effect of external reinforcement on such a failure, we developed an ex vivo model for the perfusion of segments of human saphenous veins under arterial shear stress. In veins submitted to pulsatile high pressure (mean pressure at 100 mmHg) for 3 or 7 days, the use of an external macroporous polyester mesh 1) prevented the dilatation of the vessel, 2) decreased the development of IH, 3) reduced the apoptosis of smooth muscle cells, and the subsequent fibrosis of the media layer, 4) prevented the remodelling of extracellular matrix through the up-regulation of matrix metalloproteinases (MMP-2, MMP-9) and plasminogen activator type I. The data show that, in an experimental ex vivo setting, an external scaffold decreases IH and maintains the integrity of veins exposed to arterial pressure, via increase in shear stress and decrease wall tension, that likely contribute to trigger selective molecular and cellular changes.

In situ aortobiiliac reconstruction of infected aneurysm using a single superficial femoral vein.

OBJECTIVE: To demonstrate successful in situ aortoiliac reconstruction of an infected infrarenal aneurysm using one single superficial femoral vein (SFV). METHODS: In situ reconstruction using the right SFV sutured in end-to-end anastomosis with the aorta and distally with the right common iliac artery and in end-to-side anastomosis with the left common iliac artery. RESULTS: The operating time was less than reported for aortic in situ reconstruction with bilateral SFV harvesting. The duplex scan 3 months postoperatively showed permeability of the bypass without any anastomotic stenosis or pseudoaneurysm. The right common femoral, popliteal, and greater saphenous veins were patent without thrombus, and the patient did not complain about peripheral edema. CONCLUSIONS: The use of only one instead of both the SFVs for aortobiiliac in situ reconstruction might be a way to reduce operating time and allow autogenous venous reconstruction even in patients with limited availability of venous material.

Role of hemodynamic forces in the ex vivo arterialization of human saphenous veins.

BACKGROUND: Human saphenous vein grafts are one of the salvage bypass conduits when endovascular procedures are not feasible or fail. Understanding the remodeling process that venous grafts undergo during exposure to arterial conditions is crucial to improve their patency, which is often compromised by intimal hyperplasia. The precise role of hemodynamic forces such as shear stress and arterial pressure in this remodeling is not fully characterized. The aim of this study was to determine the involvement of arterial shear stress and pressure on vein wall remodeling and to unravel the underlying molecular mechanisms. METHODS: An ex vivo vein support system was modified for chronic (up to 1 week), pulsatile perfusion of human saphenous veins under controlled conditions that permitted the separate control of arterial shear stress and different arterial pressure (7 mm Hg or 70 mm Hg). RESULTS: Veins perfused for 7 days under high pressure (70 mm Hg) underwent significant development of a neointima compared with veins exposed to low pressure (7 mm Hg). These structural changes were associated with altered expression of several molecular markers. Exposure to an arterial shear stress under low pressure increased the expression of matrix metalloproteinase (MMP)-2 and MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 at the transcript, protein, and activity levels. This increase was enhanced by high pressure, which also increased TIMP-2 protein expression despite decreased levels of the cognate transcript. In contrast, the expression of plasminogen activator inhibitor-1 increased with shear stress but was not modified by pressure. Levels of the venous marker Eph-B4 were decreased under arterial shear stress, and levels of the arterial marker Ephrin-B2 were downregulated under high-pressure conditions. CONCLUSIONS: This model is a valuable tool to identify the role of hemodynamic forces and to decipher the molecular mechanisms leading to failure of human saphenous vein grafts. Under ex vivo conditions, arterial perfusion is sufficient to activate the remodeling of human veins, a change that is associated with the loss of specific vein markers. Elevation of pressure generates intimal hyperplasia, even though veins do not acquire arterial markers. CLINICAL RELEVANCE: The pathological remodeling of the venous wall, which leads to stenosis and ultimately graft failure, is the main limiting factor of human saphenous vein graft bypass. This remodeling is due to the hemodynamic adaptation of the vein to the arterial environment and cannot be prevented by conventional therapy. To develop a more targeted therapy, a better understanding of the molecular mechanisms involved in intimal hyperplasia is essential, which requires the development of ex vivo models of chronic perfusion of human veins.

[Tumors of the musculoskeletal system: from the "lumps" to multidisciplinary care]. / Tumeurs de l'appareil locomoteur: de la simple "bosse" a la prise en charge multidisciplinaire.

Management of musculoskeletal tumours usually begins with the appearance of a lump or bump, or the onset of unspecific symptoms. A poor initial work-up, a faulty biopsy or an inadequate resection may have a severe impact on the prognosis, including re-interventions, amputation, local recurrence or systemic spread of the disease. The patient with a suspicious lesion should be referred to a "sarcoma centers" where a planned and well-performed diagnostic work-up will allow a precise diagnosis in terms of histology and staging. After a multidisciplinary discussion of the case, an accurate treatment plan is established. Such an approach allows an adequate patient management, often with a positive impact on the survival and functional outcome.

The plasminogen system in microdissected colonic mucosa distant from an isolated adenoma.

In the colon, the urokinase-type plasminogen activator (uPA), its receptor (uPAR), and plasminogen activator inhibitors, PAI-1 and PAI-2, are implicated in the transition from mucosa to adenoma and tumour progression. However, expression in the mucosa adjacent, or distant, to an adenoma has not yet been investigated. Three biopsies from mucosae adjacent (20 cm, ipsilateral) and distant (contralateral) to an isolated tubular adenoma were analysed in 14 patients and 8 controls. Laser microdissection isolated stromal and epithelial crypt components, and quantitative RT-PCR analyses of uPA, uPAR, PAI-1 and PAI-2 mRNA levels were performed. Among controls, no significant differences in the markers were noted. With left colon isolated tubular adenoma, uPA, uPAR, and PAI-2 mRNA levels were significantly increased in the adjacent mucosal stroma compared to epithelial crypt levels (p < 0.05). In right colon adenoma, the mRNA levels of these 3 molecular markers were significantly increased only in the adjacent mucosal stromal samples (p < 0.05). Isolated tubular adenoma in the colon increases significantly the mRNA levels of 3 proteolysis-associated molecular markers in the stromal, but not in the epithelial, components of adjacent mucosa. These results suggest the presence of regional and dynamic interactions in apparently non-involved mucosae.

Current management of true aneurysm of the dorsalis pedis artery.

We describe two cases of true dorsalis pedis artery aneurysms in men referred for pulsatile mass of the dorsal part of the foot. Both aneurysms were resected and grafted with interposition of a short segment of saphenous vein. Histological analysis showed true aneurysm associated with atherosclerosis. To our knowledge, only 12 cases of true dorsalis pedis artery aneurysm have been reported previously. On the basis of our experience and after reviewing the literature, the management of this uncommon pathology was discussed.

[Visceral surgery in organ transplant recipients or in patients awaiting transplantation]. / Chirurgie viscérate chez le patient greffé ou en attente d'une transplantation.

Patients receiving immunosuppression are at higher risk for gastrointestinal complications: mortality is high if they are not diagnosed and treated rapidly. Systematic screening for cholelithiasis or diverticular disease, and prophylactic surgery, are not recommended systematically anymore. Patients awaiting a transplant with abdominal symptoms should be investigated without delay and surgery, if indicated and whenever possible based on the anaesthetic evaluation, should be performed. In the transplant population, a high degree of suspicion must be raised in case of any abdominal symptom. Radiological investigations and surgery without delay are often the only ways to preserve the function of the graft and optimize the patient's survival.