[Acute limb ischemia]. / L'ischémie aiguë des membres inférieurs.

Despite major advances in the contemporary management of peripheral arterial occlusive disease, acute ischemia of the lower limb is still characterized by an important morbidity, limb threat, and mortality, and continues to pose a challenge to the vascular surgeon. Ageing of the population increases the prevalence of acute lower limb ischemia. The two principal etiologies of acute ischemia of the lower limbs are arterial embolism and in situ thrombosis of an atherosclerotic artery or of a bypass graft. Popliteal aneurysm thrombosis and vascular trauma are less common causes of severe limb ischemia. Prompt recognition and treatment of acute limb ischemia in an urgent setting are crucial, in order to shorten as much as possible the duration of the ischemia. This paper highlights diagnostic work-up (staging of the severity of ischemia) and appropriate management of acute ischemia of the lower limb. Different procedures of revascularization (operative clot removal, catheter-directed thrombolysis, bypass grafting are evaluated and their outcome results are compared.

Malgré les progrès considérables dans la prise en charge de la pathologie vasculaire, l'ischémie aiguë de membre inférieur reste grevée d'une morbidité et d'une mortalité importantes. La fréquence d'ischémie aiguë de membre augmente avec le vieillissement de la population. Les deux causes principales sont l'embolie artérielle et la thrombose d'une artère athéromateuse ou d'un pontage. Le délai de la prise en charge d'une ischémie de membre inférieur doit rester le plus court possible. Le diagnostic et la prise en charge optimale sont discutés. Les méthodes de revascularisation et les résultats sont décrits.

Late Fate of Cryopreserved Arterial Allografts.

OBJECTIVE: Initial enthusiasm for use of cryopreserved arterial allografts was subsequently tempered by suboptimal long-term outcome. Thrombosis, anastomotic pseudo-aneurysm, allograft disruption, aneurysmal degeneration, recurrent intestinal fistulization, and persistent infection are commonly reported in series with long-term follow-up. The authors reviewed their experience over the past 15 years with the use of cryopreserved arterial allografts as a vascular substitute for vascular prosthetic infection or for primary arterial infection, to investigate allograft-related complications. MATERIAL AND METHODS: A retrospective analysis of prospectively collected data was conducted for 103 cryopreserved arterial allografts inserted in 96 patients between July 2000 and July 2015. There were 78 patients with infected vascular prosthesis (IVP), nine patients with an aorto-enteric fistula (AEF), and nine patients with primary arterial infection (PAI). RESULTS: The in-hospital mortality was eight out of 78 (9%) IVP patients, three out of nine AEF patients, and zero out of nine PAI patients. Median follow-up was 49 months. Allograft-related re-interventions were necessary in 29% of the patients with IVP and four of the patients with AEF, but none of the patients with PAI. Five-year survival for the IVP, AEF, and PAI patients was 53%, 44%, and 90%, respectively. CONCLUSION: This series highlights some shortcomings of cryopreserved arterial allografts in the long term, including suboptimal outcome-results and shortage of material. The authors discuss the allograft-related complications and suggest some tricks to minimize their risk.

High prevalence of abdominal aortic aneurysm in patients with three-vessel coronary artery disease.

OBJECTIVES: Currently, the prevalence of abdominal aortic aneurysm (AAA) in patients with coronary artery disease (CAD) and the correlation between CAD severity and AAA prevalence are not clearly known. We conducted a prospective study to determine the prevalence of AAA in patients undergoing coronary angiography and to determine the risk factors and a coronary profile associated with AAA. METHODS: Over an 18-month period, abdominal aortic ultrasound was performed on 1,000 patients undergoing coronary angiography for suspected or known CAD, or prior to valve surgery. Clinical characteristics and coronary profile were collected from the patients. RESULTS: The overall number of previously repaired, already diagnosed, and new cases of AAA in the study population was 42, yielding a prevalence of 4.2%. Among the patients with newly detected AAAs, only two had an AAA diameter of >54 mm and were therefore treated surgically. In men aged ≥ 65 years, the prevalence reached 8.6%, while in men with three-vessel CAD it was 14.4%. Multivariate analysis showed that age ≥ 65 years (p = .003), male gender (p = .003), family history of AAA (p = .01), current smoking (p = .002), and three-vessel CAD (p < .001) were significantly associated with a higher prevalence of AAA. CONCLUSION: The prevalence of AAA was high in men aged ≥ 65 years and in those with three-vessel CAD regardless of age. While our findings do not prove the cost-effectiveness of screening for AAA in these high risk patients, they do support the usefulness of a quick ultrasound examination of the abdominal aorta during routine transthoracic echocardiography in such patients.

Fracture surfaces of granular pastes.

Granular pastes are dense dispersions of non-colloidal grains in a simple or a complex fluid. Typical examples are the coating, gluing or sealing mortars used in building applications. We study the cohesive rupture of thick mortar layers in a simple pulling test where the paste is initially confined between two flat surfaces. After hardening, the morphology of the fracture surfaces was investigated, using either the box counting method to analyze fracture profiles perpendicular to the mean fracture plane, or the slit-island method to analyze the islands obtained by cutting the fracture surfaces at different heights, parallel to the mean fracture plane. The fracture surfaces were shown to exhibit scaling properties over several decades. However, contrary to what has been observed in the brittle or ductile fracture of solid materials, the islands were shown to be mass fractals. This was related to the extensive plastic flow involved in the fracture process.

[Horner's syndrome revealing a spontaneous carotid artery dissection]. / Le cas clinique du mois. Syndrome de Claude Bernard-Horner révélant une dissection carotidienne spontanée.

We report a case of spontaneous carotid artery dissection suspected by the appearance of Horner's syndrome. Under medical treatment, the intramural hematoma resolved within 3 months. The patient had an uneventful recovery, without any residual neurologic deficit. Spontaneous arterial dissection is responsible for a hematoma in the arterial wall without significant trauma. The pathogenesis remains unknown. Predisposing factors seem to exist. The clinical presentation is variable mainly due to local compression of adjacent structures which can precede a transient or permanent neurological deficit. The diagnosis is confirmed by Doppler US, CT angiography or magnetic resonance angiography, the best optional investigations. The treatment mainly consists of stroke prevention by anticoagulation versus antiplatelet therapy. The role of surgery and/or endovascular techniques has not yet been confirmed.

Tackiness and cohesive failure of granular pastes: mechanistic aspects.

Granular pastes are dense dispersions of non-colloidal grains in a simple or a complex fluid. Typical examples are the coating, gluing or sealing mortars used in building applications. We study the rupture of a thick layer of mortar paste in a simple pulling test where the paste is confined between two flat surfaces. It is shown that, depending on the rheological properties of the paste and the plate separation velocity, two main failure modes are obtained. The first mode is the inwards shear flow of the paste with viscous fingering instabilities, similarly to what has been observed with Newtonian fluids and with non-Newtonian colloidal suspensions or polymer solutions. The second failure mode is stemming from the expansion of bubbles, similarly to what has been observed in soft adhesive polymer layers and, more recently, in highly viscous fluids. It is shown that the crossover between the two failure modes is determined by the conditions required to generate a pressure drop able to trigger the growth of pre-existing micro-bubbles smaller than the inter-granular distance.

Timing of carotid endarterectomy: a comprehensive review.

UNLABELLED: Some controversy exists on the best moment to treat symptomatic carotid artery disease. This controversy concerns mainly neurologically unstable patients and patients who suffered a minor stroke. The authors discuss recent literature data on the feasibility and the safety of performing urgent (within 24 to 72 hours) carotid endarterectomy (CEA) in patients presenting repetitive transient ischaemic attacks or progressing stroke. Neurologically unstable patients, suffering ischemic brain deficit caused by carotid artery stenosis, are defined according to the following criteria: two or more transient ischaemic attacks (crescendo TIAs) or a fluctuating neurological deficit evolving no longer than 24 hours (progressing stroke), no impairment of consciousness, cerebral infarct of limited size on diffusion-weighted magnetic resonance imaging of the brain and a carotid artery stenosis of 70% or more on the appropriate side. In the past, these patients were often considered at too high risk to undergo immediate carotid surgery. Many neurologists remain reluctant to confine these neurologically unstable patients for urgent carotid endarterectomy and prefer to stabilise the neurological status, arguing the increased stroke morbidity in the urgent setting. Nevertheless, the natural history of stroke- in-evolution or repetitive transient ischemic attacks is far from benign, exposing the patient to a high risk of subsequent spontaneous stroke, even under best medical treatment. Another controversy exists on the timing of surgery in patients who suffered a minor, non-disabling stroke. Is a waiting period of 6 weeks safe? Once more, the operative risk should be balanced against the anticipated natural history. Published series, and sub-analysis of the recent carotid surgery trials (NASCET, ECST) plaid for carotid surgery within two weeks of a minor stroke. CONCLUSIONS: Contemporary literature argues that neurologically unstable patients, presenting repetitive transient ischaemic attacks or progressing stroke, should be managed by urgent (within 24 to 72 hours) carotid endarterectomy, even if the peri-operative stroke-death rate is slightly higher than in the elective setting. Despite an inherent increased operative morbidity-mortality, urgent carotid endarterectomy seems to us justified by the fact that waiting for the surgery may lead to the development of a more profound stroke in these neurologically unstable patients. Their only chance for neurological recovery (partial or complete) is in the early phase (12 to 60 hours after the acute onset of the neurological syndrome of crescendo-TIAs or stroke-in-evolution). For patients presenting a minor stroke, with limited brain infarction, carotid endarterectomy should preferentially be done in a semi-urgent fashion, within two weeks.

Comparison of laparoscopic and open aortobifemoral bypass in the treatment of aortoiliac disease. Results of a contemporary series (2003-2009).

OBJECTIVES: The study objective was to describe and evaluate our single center (University Hospital Liège) experience with totally laparoscopic bypass surgery compared with conventional open surgery to treat aortoiliac occlusive disease. MATERIAL AND METHODS: A retrospective database review of all patients undergoing aortobifemoral bypass for aortoiliac occlusive disease in our center, between 2003 and 2009, was performed. During this period, a total of 251 consecutive patients were identified. Among these patients, 95 underwent totally laparoscopic aortobifemoral bypass (group I) and 156 conventional open surgery (group II). Demographic data, operative data, postoperative recovery data, complications, two-year follow-up, morbidity and mortality were analysed according to the laparoscopic and conventional open group. RESULTS: Patients included 160 men and 91 women. The mean age was 61 years (range, 40 to 88 years) in both groups. Indications for surgery were invalidating claudication in 87%, rest pain in 7%, trophic disorders in 5%, impotence in 1.6% and digestive claudication in 1.2%. Prior to bypass surgery, 11 (11.6%) for the group I and 41 (26.3%) for the group II had undergone one or more abdominal surgical procedures. A transperitoneal and retrocolic approach was preferred in all laparoscopic procedures. Laparoscopic aortobifemoral bypass (LABF) required an operative time of 242 minutes (range, 129 to 465) and open aortobifemoral bypass (OABF), 200 minutes (range, 105 to 430). The mean aortic cross clamping time was 62 minutes in group I and 33 minutes in group II. Mean blood loss was more important in group II (1010 ml) than in group I (682 ml). The average length of hospital stay was 8.1 days for LABF compared with an average of 12 days for OABF. In 21 cases (20%) conversion to open surgery was necessary in the laparoscopic group. Systemic morbidity was significantly higher in the OABF group. Thirty-day postoperative mortality was 2% for group II. There was no hospital mortality in the laparoscopic group. Twenty nine patients were lost to follow-up and the mean follow-up was 23.5 months. CONCLUSION: Analysis of the results shows that laparoscopic aortobifemoral bypass for aortoiliac occlusive disease is a safe procedure. The statistically significant advantages observed in the majority of our patients were decreased blood loss, faster post-operative recovery and shorter hospital stay. In the two groups, late morbidity attributable to the bypass prosthesis was minimal compared with other causes.

Surgical treatment of cardiovascular complications in patients with Marfan syndrome: a report of two cases and literature review.

Cardiovascular disease is the main cause of morbidity and mortality in patients with Marfan syndrome. The most life threatening complication is aortic root aneurysms leading to aortic dissection or rupture. It can be prevented by regular aortic follow-up and prophylactic aortic surgery. Modern aortic surgery has led to a substantial increase in the life expectancy of these patients. We report two cases of Marfan syndrome with cardiovascular complications. Their management is discussed according to the most recent literature.

[Should asymptomatic small popliteal artery aneurysms be operated on?]. / Faut-il opérer les petits anévrysmes poplités asymptomatiques?

The authors recently observed two patients who suffered acute lower limb ischemia secondary to thrombosis of a small (diameter of less than 2 cm) popliteal artery aneurysm. A literature search lead to the conclusion that small popliteal aneurysms, covered with mural thrombus and presenting a distorted neck due to elongation, are prone to thrombosis. Another risk factor is a restrained outflow bed as a result of previous micro-embolisations into the tibial arteries. The authors conclude that small popliteal artery aneurysms are not so innocent as is often presumed.

[Endovascular treatment of descending aortic dissection (type B)]. / Traitement endovasculaire des dissections de l'aorte descendante (type B).

Aortic dissection is one of the most serious aortic diseases by its potential for rupture, but also for other complications, such as cerebral or splanchnic ischemia, which may be fatal. If open surgery is the rule for lesions of the ascending aorta (type A), type B (not concerning the ascending aorta) is first a matter of medical treatment except when complications are present. In this case the placement of a stentgraft is a valuable alternative to open surgery. We report a patient presenting with a type B aortic dissection, characterized by rapid expansion and complicated by peri-aortic leakage, who was successfully treated by thoracic aortic stentgraft placement. This was done in a hybrid operating room associating the characteristics of a classical operating room for cardio-vascular surgery with those of an interventional radiology suite.

On the cation dependence of interlamellar and interparticular water and swelling in smectite clays.

The osmotic character of long-range interlamellar swelling in smectite clays is widely accepted and has been evidenced in the interlayer space by X-ray diffraction. Such a behavior in mesopores was not experimentally confirmed until the determination of the mesopore size distribution in Na-montmorillonite prepared from MX80 bentonite using thermoporometry experiments. This is confirmed here for other montmorillonite samples where the interlayer cations are alkaline and Ca(2+) cations. The nature of the interlayer cation is found as strongly influencing the behavior of the size and the swelling of mesopores. These results are supported by the BJH (Barrett, Joyner and Halenda) pore radius values issued from the nitrogen adsorption-desorption isotherms at the dry state. Thermoporometry results as a function of relative humidity ranging from 11% to 97% have shown an evolution of the mesopore sizes for a purified Na-montmorillonite. New thermoporometry data are presented in this article and confirm that the interparticle spaces in K-, Cs-, or Ca-montmorillonites are not strongly modified for all the range of relative humidity: the swelling is not observed or is strongly limited. It appears in contrast that only Li- and Na-montmorillonites undergo a mesopore swelling, distinct from the interlayer swelling. More generally, our results confirm the possibility to use thermoporometry or differential scanning calorimetry to study the structure and the evolution of swelling materials in wetting conditions such as natural clays or biological cells. In this paper, we describe the different key steps of the hydration of swelling clays such as montmorillonites saturated with alkaline cations. Using thermoporometry results combined with X-ray diffraction data, we distinguish the evolution of the porosity at the two different scales and propose a sequence of hydration dependent on the interlayer cation. From this study, it is shown that the interlayer spaces are not completely filled when the mesopores start to fill up. This implies that the swelling observed in the mesopores for Li and Na samples is due to an osmotic swelling. For the other samples, it is difficult to conclude definitively. Furthermore, we determine the different proportion of water (interlayer water and mesopore water) present in our samples by the original combination of (1) X-ray diffraction data, (2) the pore size distribution obtained by thermoporometry, and (3) recent adsorption isotherm results. It is found that the interlayer space is never completely filled by water at the studied relative humidity values for all samples except for the Cs sample.

Antiplatelet therapy in the perioperative period.

Antiplatelet drugs are the cornerstone treatment in the secondary prevention of arterial thrombosis. Until recently, their intake was interrupted in the perioperative period because of fear for bleeding, but new insights have challenged this old habit: In patients at high risk for atherothrombotic events who need to undergo surgery or an invasive procedure, the risk for bleeding complications because of a treatment with low-dose acetylsalicylic acid (LD ASA) needs to be balanced against the risk of atherothrombotic events after treatment discontinuation. For patients at high risk of atherothrombotic complications recent guidelines do no longer advocate to interrupt LD ASA routinely. However, the likelihood of bleeding versus atherothrombotic complications should be considered on a case-by-case basis. When continued perioperatively, the bleeding risk associated with thienopyridines (ticlopidine, clopidogrel and prasugrel) is higher than that of LD ASA. It is recommended to stop their intake 1 week before the surgical intervention, except in patients with (recent) coronary stenting.

Do we need a new carotid artery stenting trial?

Four well-conducted carotid artery trials comparing carotid artery stenting with carotid artery endarterectomy (EVA-3S, SPACE, ICSS and CREST) could not demonstrate the superiority of carotid artery stenting (CAS) over carotid artery endarterectomy (CEA). There is at the moment no level-I evidence to support widespread use of endovascular management of carotid artery disease in routine practice. In order to shead some light on the continuing debate on the role of carotid artery stenting, the authors conducted a search in contemporary published literature concerning carotid artery stenting. This extensive literature review reveals a higher peri-procedural stroke-death rate after CAS and a higher cost. Two other events hamper the value of CAS: a higher late restenosis rate and a higher risk of micro-embolisation during the procedure, compared with CEA. The authors conclude that the prevailing overenthusiasm of interventionalists (vascular surgeons, radiologists, cardiologists) for carotid artery stenting is not justified.

Thrombolysis of occluded infra-inguinal bypass grafts: is it worthwhile?

BACKGROUND: Thrombosis of an infra-inguinal bypass graft often results in a limb-threatening ischemia. There is no consensus on the optimal management strategy. AIM OF THE STUDY: To analyse safety and efficacy of catheter-guided intra-arterial thrombolysis to re-open thrombosed infra-inguinal bypass grafts and to identify factors that influence graft patency and limb salvage rate after thrombolytic procedures. METHODS: A continuous cohort-study of 106 thrombolytic procedures between 1993 to 2008. RESULTS: Despite a high initial success rate (76%), the mid-term results are less convincing, with a 58% re-occlusion rate at 45 months follow-up. Thrombosed vein grafts, old (2 weeks or more) occlusions, poor run-off and failure to identify or rectify an underlying causative stenosis are determinant for a poor long-term outcome of thrombolytic procedures. COMMENTS: The outcome results of author's experience are consistent with literature reports. Thrombolysis of occluded infra-inguinal bypass grafts should be limited to selective cases (recent occlusion, prosthetic or vein graft in place since 1 year or more, critical limb ischemia). Despite its obvious advantages, the long-term outcome of thrombolytic procedures is deceiving. The inherent risk of hemorrhagic complications should also be taken in account at the decision making of treatment strategy. The question whether, in general, catheter-guided selective intra-arterial thrombolysis offers a significant advantage over operative revascularisation (thrombectomy or new bypass) remains unanswered. A more selective approach seems to favour thrombolysis as most appropriate strategy in the management of recent (< 2 weeks) thromboses of grafts in place since at least 1 year.

Endovascular aneurysm repair (EVAR): does it fulfil all its promises?

In the trend of the endovascular revolution for occlusive arterial disease, management of aneurysmal disease has known an analogous change in the nineties. Elective endo-aneurysmal stentgrafting (EVAR or endovascular aneurysm repair) is nowadays of widespread application in contemporary practice all over the world, sometimes by over-enthusiast proponents. There is a burden of recent publications on that topic. Critical analysis of relevant data reveal compelling evidence that elective EVAR is a safe procedure with a threefold reduced 30-day morbidity-mortality, when compared to conventional open aneurysm repair. EVAR also deemed efficace in terms of AAA rupture prevention. At the other hand, mid-term follow-up revealed that EVAR does not endure at the long-term in any late survival benefit, compared to open AAA repair. The major concern and drawback of EVAR is its higher cost and the need for indefinite, life-long surveillance, with a 20% reintervention rate (almost catheter-based endovascularly) at 5-year follow-up. In this review-paper, short-term gains of EVAR are balanced against the inherent disadvantages and long-term losses. According best available evidence, EVAR should not longer be the first choice for high-risk patients, judged unfit for open aneurysm repair. There also exist doubt on the use of EVAR in young fit patients with an anticipated long life expectancy. In approximately half of the AAA patients, EVAR can be considered as the appropriate treatment option.

Bilateral humeral artery aneurysm as a cause of digital ischaemia.

Bilateral humeral artery aneurysm is a very rare condition. Simultaneous bilateral complication of these aneurysms makes it even more unusual. We present a case of a 44-year-old man with bilateral digital ischaemia as a complication of a bilateral humeral artery aneurysm. Anamnestic, clinical and per-operative findings led to several hypotheses. A venous bypass graft was done to exclude both aneurysms and to arrest the embolisation into the digital arteries.

Spinal cord stimulation. New regulation of national health insurance.

Since January 1, 2008, the Belgian national health insurance (INAMI/RIZIV) edited a new agreement for the prolongation of the pilot-study on spinal cord stimulation for chronic critical unreconstructable lower limb ischemia. After a short introduction and a summary of the results of the initial Belgian pilot study (2000-2005) on spinal cord stimulation, the official new text is now published in both languages.