Clinical Potential of Hydrogen Sulfide in Peripheral Arterial Disease.

Peripheral artery disease (PAD) affects more than 230 million people worldwide. PAD patients suffer from reduced quality of life and are at increased risk of vascular complications and all-cause mortality. Despite its prevalence, impact on quality of life and poor long-term clinical outcomes, PAD remains underdiagnosed and undertreated compared to myocardial infarction and stroke. PAD is due to a combination of macrovascular atherosclerosis and calcification, combined with microvascular rarefaction, leading to chronic peripheral ischemia. Novel therapies are needed to address the increasing incidence of PAD and its difficult long-term pharmacological and surgical management. The cysteine-derived gasotransmitter hydrogen sulfide (H2S) has interesting vasorelaxant, cytoprotective, antioxidant and anti-inflammatory properties. In this review, we describe the current understanding of PAD pathophysiology and the remarkable benefits of H2S against atherosclerosis, inflammation, vascular calcification, and other vasculo-protective effects.

[Management of aortic disease: the importance of an organized care network]. / Prise en charge de la maladie aortique : l'importance d'une filière des soins.

Pathologies of the aorta are a complex cardiovascular diseases requiring multidisciplinary management coordinated by specialized centers able to ensure adequate patient volume. This article describes the care pathways, based on the most recent data of the literature, to optimize the management of aortic diseases).

Les pathologies de l'aorte sont des maladies cardiovasculaires complexes nécessitant une prise en charge multidisciplinaire et cordonnée par des centres spécialisés pouvant assurer un volume adéquat de patients. Cet article décrit la filière des soins, basée sur les données les plus récentes de la littérature, pour optimiser la prise en charge de la maladie aortique.

Hydrogen Sulphide Release via the Angiotensin Converting Enzyme Inhibitor Zofenopril Prevents Intimal Hyperplasia in Human Vein Segments and in a Mouse Model of Carotid Artery Stenosis.

OBJECTIVE: Hypertension is a major risk factor for intimal hyperplasia (IH) and re-stenosis following vascular and endovascular interventions. Preclinical studies suggest that hydrogen sulphide (H2S), an endogenous gasotransmitter, limits re-stenosis. While there is no clinically available pure H2S releasing compound, the sulfhydryl containing angiotensin converting enzyme inhibitor zofenopril is a source of H2S. Here, it was hypothesised that zofenopril, due to H2S release, would be superior to other non-sulfhydryl containing angiotensin converting enzyme inhibitors (ACEi) in reducing intimal hyperplasia. METHODS: Spontaneously hypertensive male Cx40 deleted mice (Cx40-/-) or wild type (WT) littermates were randomly treated with enalapril 20 mg or zofenopril 30 mg. Discarded human vein segments and primary human smooth muscle cells (SMCs) were treated with the active compound enalaprilat or zofenoprilat. IH was evaluated in mice 28 days after focal carotid artery stenosis surgery and in human vein segments cultured for seven days ex vivo. Human primary smooth muscle cell (SMC) proliferation and migration were studied in vitro. RESULTS: Compared with control animals (intima/media thickness 2.3 ± 0.33 µm), enalapril reduced IH in Cx40-/- hypertensive mice by 30% (1.7 ± 0.35 µm; p = .037), while zofenopril abrogated IH (0.4 ± 0.16 µm; p < .002 vs. control and p > .99 vs. sham operated Cx40-/- mice). In WT normotensive mice, enalapril had no effect (0.9665 ± 0.2 µm in control vs. 1.140 ± 0.27 µm; p > .99), while zofenopril also abrogated IH (0.1623 ± 0.07 µm; p < .008 vs. control and p > .99 vs. sham operated WT mice). Zofenoprilat, but not enalaprilat, also prevented IH in human vein segments ex vivo. The effect of zofenopril on carotid and SMCs correlated with reduced SMC proliferation and migration. Zofenoprilat inhibited the mitogen activated protein kinase and mammalian target of rapamycin pathways in SMCs and human vein segments. CONCLUSION: Zofenopril provides extra beneficial effects compared with non-sulfhydryl ACEi in reducing SMC proliferation and re-stenosis, even in normotensive animals. These findings may hold broad clinical implications for patients suffering from vascular occlusive diseases and hypertension.

Predictive Factors of Surgical Complications in the First Year Following Kidney Transplantation.

BACKGROUND: In the recent years, an increased use of marginal donors and grafts and a growing prevalence of peripheral arterial disease in the recipients have been observed. Meanwhile, the open surgical technique for kidney transplantation has not changed. The aim of this study is to analyze all surgical complications occurring in the first year after kidney transplant and to determine potential predictive risk factors. METHODS: Data of the 399 patients who underwent kidney transplant in our University Hospital between January 2006 and December 2015 were retrospectively reviewed. The primary endpoint was the overall rate of vascular, parietal and urological complications at 1 year following kidney transplantation. The secondary outcomes were graft and patient' survival rates, and the identification of predictive factors of the surgical complications. RESULTS: 24% of patients developed 134 complications. Vascular complication represented 39% of all complications and resulted in 9 graft losses. Parietal and urological complications represented 46-15% of all complications, respectively, No parietal or urological complications were associated with graft loss. 5 patients died during the 1st year, none of these cases was associated with graft loss. The graft survival rate reached 96% at 1 year, including patients still alive. The occurrence of surgical complication was associated with reduced graft survival at 1 year. Using a multivariate analysis, 4 predictive factors were identified: age, deceased donor, operative time and dyslipidemia. CONCLUSION: Surgical complications after kidney transplantation remained frequent and age, deceased kidney donors, and operative time were identified as risk factors. As vascular complications were a major cause of early graft loss, efforts should aim to reduce their occurrence to increase graft survival.

The effects of COVID-19 pandemic on patients with lower extremity peripheral arterial disease: A near miss disaster.

BACKGROUND: The COVID-19 pandemic has led to widespread postponement and cancelation of elective vascular surgeries in Switzerland. The consequences of these decisions are poorly understood. PATIENTS AND METHODS: In this observational, retrospective, single-center cohort study, we describe the impact of COVID-19 pandemic containment strategies on patients with lower extremity peripheral arterial disease (PAD) referred during the period March 11, to May 11, 2020, compared to the same time frames in 2018 to 2019. Patients admitted for acute limb ischemia (ALI) or chronic PAD and undergoing urgent or elective vascular surgery or primary amputation were included. Patients' characteristics, indications for admission, and surgical features were analyzed. The occurrence of 30 day outcomes was assessed, including length of stay, rates of major adverse cardiovascular events (MACE) and major adverse limb events (MALE), and procedural and hemodynamic success. RESULTS: Overall, 166 patients were included. Fewer subjects per 10 day period were operated in 2020 compared to, 2018 to 2019 (6.7 vs. 10.5, respectively; P < 0.001). The former had higher rates of chronic obstructive pulmonary disease (COPD) (25% vs. 11.1%; P = 0.029), and ASA score (3.13 vs. 2.90; P = 0.015). The percentage of patients with ALI in 2020 was about double that of the same period in 2018 to 2019 (47.5% vs. 24.6%; P = 0.006). Overall, the types of surgery were similar between 2020 and 2018 to 2019, while palliative care and primary amputations occurred only in 2020 (5 out 40 cases). The rate of post-operative MACE was significantly higher in 2020 (10% vs. 2.4%; P = 0.037). CONCLUSIONS: During the first state of emergency for COVID-19 pandemic in 2020, less regular medical follow-up and hindered hospital access could have resulted in more acute and advanced clinical presentations of patients with PAD undergoing surgery. Guidelines are needed to provide appropriate care to this vulnerable population and avoid a large-scale disaster.

[Screening for peripheral arterial disease : role of the primary care physician]. / Dépistage de l'artériopathie oblitérante des membres inférieurs : rôle du médecin de premier recours.

Peripheral arterial disease (PAD) is a widespread disease with high impact on global health. While general population screening is not currently indicated, the primary care physician has the critical role of identifying asymptomatic patients who are particularly at risk for PAD and could therefore benefit from screening. In addition, he or she must recognize the typical and atypical clinical presentations of patients with symptomatic PAD to ensure proper diagnosis and care. After an adequate medical history and clinical examination, the first diagnostic test is the « Ankle-Brachial Index ¼ (ABI) calculation. In case of pathologic ABI (≤ 0.9, or > 1.4), or in case of normal or borderline ABI with symptoms, the patient should be referred to a vascular medicine physician for diagnostic confirmation and management.

L'artériopathie oblitérante des membres inférieurs est une maladie très répandue ayant un impact remarquable sur la santé mondiale. Bien que le dépistage dans la population générale ne soit pas indiqué, le médecin de premier recours a le rôle essentiel d'identifier les patients asymptomatiques qui pourraient bénéficier du dépistage. En outre, il·elle doit reconnaître les présentations cliniques typiques et atypiques chez les patients symptomatiques, afin d'assurer le diagnostic. Après l'anamnèse et l'examen clinique, le premier test de dépistage est le calcul de l'index cheville-bras. En cas de valeurs pathologiques (≤ 0,9 ou > 1,4), normales ou « borderline ¼ en présence de symptômes, le patient doit être adressé à un angiologue pour confirmation du diagnostic et prise en charge.

[Who do you screen for an abdominal aortic aneurysm ?] / Chez qui effectuer un dépistage de l'anévrisme de l'aorte abdominale ?

Abdominal aortic aneurysm (AAA) represents an important public health problem. The early detection and treatment as well as follow-up of an AAA are important to reduce the high mortality rate associated with its rupture. Despite the decline of the prevalence of AAA in the last decades, the latest international recommendations have reaffirmed that screening in men remains cost-effective. In contrast, the data and recommendations for women are unclear. The best method for AAA screening is abdominal ultrasound. The aim of this paper is to present an up-to-date review of the indications for AAA screening based on the latest recommendations.

L'anévrisme de l'aorte abdominale (AAA) reste toujours un problème de santé publique malgré les progrès technologiques réalisés dans sa prise en charge. Le diagnostic précoce et le traitement ainsi que le suivi d'un AAA sont importants pour prévenir le taux de mortalité très élevé associé à sa rupture. Bien que la prévalence de l'AAA ait diminué ces dernières décennies, les dernières recommandations internationales ont réaffirmé qu'un dépistage chez les hommes reste rentable. En revanche, les données et les recommandations concernant la femme ne sont pas claires. L'examen de choix pour le dépistage des AAA est l'échographie abdominale. Cet article vise à mettre à jour les indications de dépistage de l'AAA en fonction des dernières recommandations.

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.

[Lower extremity peripheral artery disease†: local and systemic complications]. / Artériopathie oblitérante des membres inférieurs†: complications locales et systémiques.

Lower extremity peripheral artery disease can lead to local complications but also to complications in other vascular areas, stressing the systemic impact of the atheromatous disease. The current concepts of MALE (Major Adverse Limb Events) and MACE (Major Adverse Cardiac Events) encompass these risks. The systemic vascular complications, as well as the ones at lower extremities, are associated with significant morbidity and mortality. An optimal therapeutic management and healthy lifestyle, such as regular exercise, are crucial to limit the risk of unfavorable progression of the arterial disease. A close collaboration between the general practitioner and the angiologist is a key to adequate initial management and follow-up of the patients.

L'artériopathie oblitérante des membres inférieurs (AOMI) est associée à des complications locales et dans d'autres territoires vasculaires, témoignant du caractère généralisé de la pathologie athéromateuse. Les notions récentes de MALE (major adverse limb events) et MACE (major adverse cardiac events) reflètent cette approche conceptuelle de la maladie athéromateuse. Les complications vasculaires systémiques et spécifiques aux membres inférieurs sont à l'origine d'une morbi-mortalité significative. Une prise en charge optimale médicamenteuse et d'hygiène de vie, en particulier une activité physique régulière, sont fondamentales pour limiter les risques d'évolution défavorable de la pathologie artérielle. La collaboration étroite entre le médecin interniste-généraliste et l'angiologue est à la base de la prise en charge initiale et du suivi des patients.

[The vascular access of hemodialysis patients - What should the primary care physician know about ?] / Accès vasculaire du patient hémodialysé - Que doit savoir le spécialiste en médecine interne générale ?

The most frequent dialysis modality in Switzerland is hemodialysis. Patients need a proper vascular access for this modality. There are three types of vascular access for hemodialysis : arteriovenous fistula, arteriovenous graft and central venous catheters. In this article, we will discuss the most important parameters that need to be taken into account when choosing the most appropriate access. We present the advantages and disadvantages of each vascular access, as well as their main local (thrombosis, infection, steal syndrome) and systemic (heart failure, pulmonary hypertension) complications, which may also be encountered by primary care physicians.

La majorité des patients dialysés en Suisse utilisent comme modalité l'hémodialyse. Cette technique nécessite un accès vasculaire permanent, dont il existe trois types : la fistule artérioveineuse native, la fistule artérioveineuse prothétique et le cathéter veineux central. Dans cet article, nous passerons en revue les paramètres à prendre en compte avant la création et l'utilisation d'une fistule. Nous discuterons les avantages et les inconvénients des différents accès ainsi que des complications locales (thrombose, infection, syndrome de vol) et systémiques (insuffisance cardiaque, hypertension pulmonaire) les plus fréquentes qu'ils peuvent engendrer et auxquelles les médecins en première ligne peuvent aussi être confrontés.

A Multicenter Experience With a New Fenestrated-Branched Device for Endovascular Repair of Thoracoabdominal Aortic Aneurysms.

PURPOSE: To investigate the outcomes of patients who were treated for thoracoabdominal aortic aneurysms (TAAAs) using custom-made fenestrated-branched stent-grafts. METHODS: A consecutive series of 108 patients (mean age 73.5 years; 73 men) with TAAA were treated with E-xtra Design Engineering customized fenestrated-branched stent-grafts between November 2011 and January 2017. Data on baseline characteristics, procedures, and clinical follow-up were collected from 6 regional European surgical centers for retrospective analysis of endoleaks, reinterventions, and target vessel patency. The median aneurysm diameter was 6.75 cm (range 5.5-13). The distribution of the TAAA according to the modified Crawford classification of extent was 25 (24%) type I, 19 (17%) type II, 20 (18%) type III, 29 (27%) type IV, and 15 (14%) type V. RESULTS: Technical success was achieved in 95% (103/108) of cases. Major early perioperative complications occurred in 40 (37%) patients. The 30-day mortality was 9.2% (10/108), and perioperative spinal cord ischemia was observed in 6 (5.5%) patients [2 (1.8%) permanent]. During the mean follow-up of 17.6 months (range 3-52), 28 (26%) patients required late reintervention. Two patients died due to aneurysm- or procedure-related causes. The estimated survival rates at 1, 2, and 4 years were 87%, 84%, and 51%, respectively. The estimated target vessel patency rates at the same time points were 95%, 91%, and 90%, respectively. The freedom from reintervention estimates were 84% and 73% at 1 and 4 years, respectively. CONCLUSION: Endovascular repair of TAAA using Jotec customized fenestrated-branched stent-grafts appears to be safe and effective in the early to midterm. The considerable rate of secondary interventions indicates that further improvements, graft surveillance, and follow-up are required.

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.

Laparoscopic Resection of a Middle Colic Artery Aneurysm.

We report herein the successful laparoscopic resection of an asymptomatic 3-cm middle colic artery aneurysm in a young woman. Endovascular treatment represents nowadays the first-line option facing visceral artery aneurysm, but in this case, embolization was excluded because of hostile anatomy. Advantages of laparoscopic approach were the safe resection of the aneurysm with immediate evaluation of the bowel tolerance and the possibility of a histological examination of the arterial wall, without the disadvantages of laparotomy.

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.

Bilateral Renal Autotransplantation May Be an Effective and Definitive Treatment in Case of Loin Pain Haematuria Syndrome.

Loin pain haematuria (LPHS) is a rare and difficult-to-diagnose syndrome. Different therapeutic approaches have been used historically with little or no success. We report a case of LPHS in which bilateral renal autotransplantation led to pain relief, cessation of all medication and no recurrence beyond two years of follow-up.

[Fibromuscular dysplasia and hypertension : beyond renal arteries]. / Hypertension et dysplasie fibromusculaire :au-delà des artères rénales.

Fibromuscular dysplasia (FMD) is a disease associated with abnormalities of the arterial wall of medium-sized arteries. These abnormalities can lead to stenosis or less frequently to dissections or aneurysms. FMD is probably more frequent than initially thought. Nowadays, it is often a chance finding during a radiologic exam. In symptomatic cases, poor organ perfusion due to stenosis, dissection or aneurysm rupture may lead to the diagnosis. The aim of this non-systematic review illustrated with a clinical case is to present our current knowledge of FMD and to highlight the necessity of a standardized and multidisciplinary work-up to improve management of affected patients and understanding of the disease.

La dysplasie fibromusculaire (DFM) est une maladie associée à des anomalies de la paroi des artères de moyen calibre pouvant entraîner des sténoses et plus rarement des anévrismes ou des dissections. Moins rare qu'on ne le pensait initialement, la DFM est parfois découverte fortuitement lors d'un bilan de santé lorsque la maladie est asymptomatique ou lors des manifestations secondaires à l'ischémie de l'organe atteint, conséquence d'une sténose, d'une dissection ou d'une rupture de la paroi artérielle. A partir d'un cas clinique, cette revue non systématique illustre nos connaissances actuelles de la DFM et souligne l'importance d'une prise en charge multidisciplinaire et standardisée pour de meilleurs soins aux patients et une meilleure compréhension de la maladie.

[Interventional treatment of venous insufficiency]. / Prise en charge interventionnelle de l'insuffisance veineuse superficielle des membres inférieurs.

Interventional treatment of venous insufficiency has been revolutionized by endovascular techniques. Some of these techniques, and particularly thermal ablation (endovenous laser, radiofrequency) are now recommended as first-line therapy in the latest international guidelines. This is because of less post-operative pain, a shorter leave from employment and similar or lower recurrence rate. Endovenous techniques allow safer and more efficient treatment of certain particular conditions : small saphenous vein, ulcers, and recurrent varicose veins. In addition to clinical history and examination, a duplex sonography of deep and superficial veins, performed by an angiologist, is the most important exam in order to determine proper indication and best treatment strategy for each patient.

La prise en charge de l'insuffisance veineuse des membres inférieurs a été révolutionnée par l'avènement des techniques endoveineuses. En particulier, l'ablation thermique par laser endoveineux, ou radiofréquence des troncs saphéniens, a remplacé la chirurgie comme technique de référence dans les dernières guidelines publiées, notamment en raison d'une diminution des douleurs postinterventionnelles et de la durée d'incapacité de travail avec un taux de récidives identique, voire inférieur. Les techniques endoveineuses permettent, en outre, de traiter certaines indications avec un niveau d'efficacité et de sécurité accru : traitement de la petite veine saphène, ulcères et récidives de varices. Afin de déterminer l'indication et la meilleure stratégie de prise en charge, un bilan veineux par écho-Doppler par un angiologue est une étape obligatoire.

[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.