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Biomedical subjects

Marc Sapoval

Publications and source records attributed to Marc Sapoval.

17 recordsLinked to original sources

[Vascular Ehlers-Danlos syndrome].

The vascular type of Ehlers-Danlos syndrome (EDS) is a rare genetic disease transmitted as an autosomal dominant trait. It is distinguished from other forms of EDS by its unstable acrogeric morphotype and by vascular, gastrointestinal, and obstetrical complications. Diagnosis is based on various clinical signs, noninvasive imaging, and on the identification of a mutation of the COL3A1 gene, which provides diagnostic certainty but has a sensitivity of only 61%. When two major diagnostic criteria are present, a genetic test should be proposed, performed and its result presented in a multidisciplinary group. The precautionary principle requires that preventive measures be implemented when the diagnosis is suspected. All artery puncture, surgery, and gastrointestinal and uterine endoscopy are contraindicated, permissible only in life-threatening emergencies. Straining against a closed glottis and all other situations or drugs likely to raise blood pressure must be avoided. Contraception must be discussed to avoid pregnancy during the diagnostic period. Arterial lesions suggestive of the disease include dissecting aneurysms of the internal carotid and iliac arteries and of the anterior visceral branches of the abdominal aorta, fusiform aneurysms of the splenic artery, and early onset nontraumatic direct carotid-cavernous fistulae. Early-onset varicose veins, spontaneous peritonitis or unusually important perineal lesions after giving birth should also attract the physician's attention. Psychological treatment and support of patients and their families is essential, to help them both to live with their disease and to deal with the information and screening issues. The prognosis of Ehlers-Danlos syndrome, vascular type, is grim but there is wide interindividual variability and life expectancy is best among patients receiving regular follow-up. Management by an experienced multidisciplinary team, implementation of drastic prevention measures and, depending on the results of the BBEST study, the possible prescription of beta-blockers should help to reduce the risk of complications and justify hope for a real improvement in prognosis in the near future.

Adult↗

Implant degradation and poor healing after endovascular repair of abdominal aortic aneurysms: an analysis of explanted stent-grafts.

PURPOSE: To study explanted stent-grafts to achieve a better understanding of the mechanisms of failure after endovascular treatment of abdominal aortic aneurysms (AAA). METHODS: Twelve stent-grafts were harvested at autopsy (n=3) or during surgical conversion (n=9). Device alterations were investigated by macroscopic examination, radiography, and surface analysis techniques. Healing around the implants was studied via histology and immunohistochemistry, with particular attention to the stent-graft/tissue interface. RESULTS: Degradation was more important with Vanguard stent-grafts (off the market) than with AneuRx and Talent stent-grafts, but rupture of nitinol wires and poor surface finish in Talent stent-grafts raise concern about their corrosion resistance and long-term stability. Poor healing was observed around stent-grafts even after several years of implantation, with absence of vascular smooth muscle cells, fibroblasts, and collagen formation. In addition to the well-known foreign body reaction around the graft, numerous polymorphonuclear cells characteristic of the first step of healing were present in tissues around stent-grafts retrieved at surgical conversion. Factors explaining the lack of tissue organization around stent-grafts are discussed. CONCLUSION: The long-term stability of implants remains a concern and requires more transparency from manufacturers regarding the surface properties of their devices. Lack of neointima formation impairs biological fixation of the implant to the vessel wall, leading to possible endoleaks and migration. New-generation stent-grafts promoting biological fixation should be developed to improve clinical outcomes of this minimally invasive treatment.

Aged↗

[Role of interventional radiology in the management of critical limb ischemia].

Critical limb ischemia is a growing public health problem with major human and medical costs. Primary amputation is the rule in most countries and hospitals, but has major functional, psychological and financial consequences. By using a combination of endovascular and surgical techniques, it is now possible to save 9/10 limbs at risk. Because of the frequency of atheromatous disease in these patients, often involving the carotid and coronary networks, aggressive management of risk factors and close surveillance are mandatory. The first step, on which subsequent management depends, is the anatomical workup. Arteriography is currently the only technique that offers a robust workup and, in most cases, permits interventional radiology procedures under local anesthesia and during the same session. Various techniques can be used, depending on the type of lesions, from plain balloon angioplasty to stenting, subintimal recanalization, and use of a cutting balloon. We review the different interventional radiology approaches available in this setting, and their results relative to bypass surgery.

Aged↗

Reduced immunoregulatory CD31+ T cells in patients with atherosclerotic abdominal aortic aneurysm.

BACKGROUND: Cell-mediated immunity is considered to contribute to the pathogenesis of abdominal aortic aneurysms (AAA). In particular, infiltrating macrophages and CD8+ T lymphocytes participate in the destruction of the aortic wall extracellular matrix and smooth muscle cells. We surmise that these pathological events are controlled by circulating regulatory lymphocytes. METHODS AND RESULTS: Circulating CD4+/CD31+ cells were reduced in AAA patients (n=80, 8.9+/-0.6%) as compared with controls (n=69, 13.7+/-0.8%; P<0.001) and inversely proportional to AAA size. Exclusion of the aneurysm by an endoprothesis did not affect CD31+ T cell values. Reduction of blood CD4+/CD31+ cells was not attributable to their enrichment in AAA tissue. In contrast, CD8+/CD31+ cells were slightly reduced in the blood while increased in the aneurysmal tissue (29.2+/-0.5 versus 20.2+/-4.7% in blood, n=6; P<0.05). Remarkably, high percentages of CD4+/CD31+ cells were able to regulate proliferation and cytokine production of CD8+ lymphocytes, as well as CD8+ cell-mediated cytotoxicity of aortic smooth muscle cells (P<0.01). Finally, CD4+/CD31+ cells reduced the production and activity of metalloproteinase-9 by lipopolysaccharide-stimulated macrophages. CONCLUSIONS: Circulating CD4+/CD31+ T cells regulate macrophage and CD8+ T cell activation and effector function in the arterial wall. Their reduction might promote the development of AAA.

Aged↗

[Management of patients with intermittent claudication].

Management of patients with intermittent claudication must be first the treatment of the atherosclerosis process: cessation of smoking, antiplatelet therapy, betablockers, angiotensin-converting-enzyme inhibitor and cholesterol lowering in order to have a LDL cholesterol < 1 g/L. Treatment of intermittent claudication depends of the arterial lesions. If an endovascular procedure is feasible and safe, iliac stenosis or short iliac occlusion, it permits a spectacular improvement. Most often only medical treatment with physical training is advisable. Surgical revascularisation is rarely justified in patients with intermittent claudication.

Adrenergic beta-Antagonists↗

[Management of a patient with critical limb ischemia].

The severity of the prognostic of critical limb ischemia imposes a multidisciplinary approach, done by a highly specialised centre. A delay in managing this condition increases significantly the risk of amputation. For most patients, a revascularisation procedure, surgical or endovascular, can be considered, since the aim of the treatment is to restore an arterial flux to permit cicatrisation and relieve pain. When the choice is possible, endovascular techniques are preferred, because more simple, done without anaesthesia and charged of less complications rate. The choice between two techniques is never simple and imposes the intervention of a multidisciplinary staff composed by vascular specialist, vascular surgeons and interventional radiologists. The aim of the medical treatment, waiting for the revascularisation, is to control the pain and the infection, prevent progression of the lesions and to optimise respiratory and cardiac functions.

Angiography↗

Compliance of abdominal aortic aneurysms evaluated by tissue Doppler imaging: correlation with aneurysm size.

OBJECTIVES: Several studies have shown that an increase in abdominal aortic aneurysm (AAA) growth rate occurs when the diameter reaches 40 to 50 mm. AAA expansion is related to remodeling of the parietal extracellular matrix. The parietal mechanisms involved in this critical phase of sudden increase remain unexplained. Analysis of AAA wall movements and determination of AAA compliance may provide information about the constitution of the arterial wall. If a change in parietal wall motion somewhere between 40 and 50 mm could be shown, this would contribute to the understanding of the growth of AAA. Furthermore, it would provide a valuable additional parameter for AAA monitoring. This study had two aims: first, to evaluate the relationship between AAA compliance and maximum diameter using the tissue Doppler imaging system; and second, to test the hypothesis of a change in AAA behavior at around 45 mm in diameter. METHODS: Fifty-six patients with AAA (mean diameter, 39 mm) were prospectively investigated using the tissue Doppler imaging system, which provides information concerning arterial wall motion. Maximum mean segmental dilation (MMSD), segmental compliance, pressure strain elastic modulus (Ep), and stiffness were determined and related to the maximum diameter of AAA. Results After natural log transformation of all variables, there was a significant positive linear relationship between maximum diameter and both MMSD (P < .001) and segmental compliance (P < .001) but not with Ep or stiffness (P = .37 and .22, respectively). MMSD and segmental compliance were significantly higher in AAA > or = 45 mm than in AAA < 45 mm (P < .0002 and <. 004, respectively). Ep and stiffness tended to decrease in larger AAAs, but this was not statistically significant (P < .43 and .24, respectively). Dispersion of Ep and stiffness values seemed to be wider among AAA < 45 mm compared with those > or = 45 mm. CONCLUSION: Compliance parameters can easily be measured during routine AAA ultrasound monitoring using the tissue Doppler imaging system. The study showed an increase in MMSD and segmental compliance as well as a nonsignificant trend toward increased distensibility (decreased Ep and stiffness) with increased AAA diameter. A change in dispersion of AAA distensibility may appear around 45 mm in diameter, but a larger study will be needed to clarify this.

Abdominal Wall↗

Low-profile stent system for treatment of atherosclerotic renal artery stenosis: the GREAT trial.

PURPOSE: The Palmaz Genesis Peripheral Stainless Steel Balloon Expandable Stent in Renal Artery Treatment (GREAT) Trial was designed to assess the safety and performance of a low-profile stent for the treatment of obstructive renal artery disease by looking at 6-month renal artery patency uniformly analyzed by a Core Lab. MATERIALS AND METHODS: Fifty-two consecutive patients (mean age, 63.7 years) were successfully treated with the Palmaz Genesis Peripheral Stent (Cordis, Miami, FL) on the Slalom 0.018-inch Delivery System (Cordis Europe N.V., Oosteinde 8, NLO-9301 LJ Roden, The Netherlands) at 11 investigational centers. Patients with severe renal failure and > 8-mm renal artery were excluded. Primary endpoint was angiographic determination of in-stent percent diameter stenosis at 6 months. Fifty-one patients were treated with one stent, one patient was treated with two stents to cover the complete lesion. RESULTS: Mean percentage diameter stenosis before renal angioplasty was 68.2% +/- 12.0%. No stent implantation failure, displacement, need for additional stent implantation, or procedural complication was observed. Six-month angiography was performed in 41 of 52 patients (79%) resulting in a mean in-stent percent diameter stenosis or Quantitative Vessel analysis (QVA) at 6 months of 23.9%. The in-stent binary (percent diameter stenosis > 50%) restenosis rate at 6 months was 14.3%. No fatal events occurred up to 6 months after implantation. Major adverse events occurred in five patients: four patients (7.7%) required a revascularization and one patient (1.9%) experienced a cerebrovascular event, which regressed spontaneously. CONCLUSIONS: The Palmaz Genesis stent (Cordis) provides good results for renal artery stent placement, with an in-stent binary restenosis rate (percent diameter stenosis > 50%) at 6 months of 14.3% as determined with angiography.

Aged↗

Aortic compliance in healthy subjects: evaluation of tissue Doppler imaging.

Increased compliance of abdominal aortic aneurysms at maximum diameter over time might be related to rupture. Compliance could, therefore, be valuable in their management. However, such measurement requires a sophisticated system. An original arterial wall-motion measurement technique, based on tissue Doppler imaging (TDI) and providing segmental exploration, was applied to the study of aorta walls. We report its validation in healthy subjects. Technical feasibility was reliable. The time required for sequence acquisition and transfer was suitable for routine clinical use and the quality of the sequences provided precise identification of the aorta wall/lumen interface and accurate segmentation. The values characterising normal aortic compliance were similar to those previously published, and the initial results concerning reproducibility were appropriate for clinical studies. Further refinements may improve it. This study validates the TDI system for measurement of abdominal aortic compliance in healthy subjects. Study of application to aneurysm compliance is in progress.

Adult↗

Compliance of abdominal aortic aneurysms: evaluation of tissue Doppler imaging.

Expansion of abdominal aortic aneurysms (AAA) is due to remodeling of the parietal extra-cellular matrix and may lead to rupture. This remodeling is reflected by compliance which may be an indicator of AAA behavior and thus useful for clinicians. Tissue Doppler Imaging (TDI) is an ultrasonographic modality which allows wall motion measurements along an arterial segment. It has previously been evaluated in normal aortas and was then evaluated in thirty-five patients with AAA. Mean values (+/-standard deviation) characterizing maximum diameter AAA compliance were dilation 809 mum (+/-465), strain 2.2% (+/-1), pressure strain elastic modulus 3.94 10(5) Pa [3.25; 4.8] and stiffness 28.8 [24; 34.5], last values being expressed as geometric mean [interquartile range]. They were in accordance with those previously obtained with other systems. Segmental parameter values were maximum mean segmental dilation 534 mum (+/-305) and segmental compliance 14.6 (+/-8.3) 10(-2) mum/Pa. Reproducibility was appropriate for clinical studies. The TDI system is simple and reliable for measurement of AAA compliance, and compliance can easily be recorded during routine ultrasound control.

Abdominal Wall↗

Growth factors improve latissimus dorsi muscle vascularization and trophicity after cardiomyoplasty.

BACKGROUND: Dynamic cardiomyoplasty consists of wrapping the electrostimulated latissimus dorsi muscle (LDM) around the failed heart. Partial ischemia followed by atrophy of the middle and distal part of the LDM were observed in 30% of clinical cases after LDM flap elevation from its origin. In the current study, we hypothesized that local administration of growth factors at the LDM/epicardial interface could improve muscle vascularization and trophicity. METHODS: In 24 sheep, dynamic cardiomyoplasty was performed using the left LDM. A multiperforated catheter was positioned at the LDM/epicardial interface for a weekly administration, during a 1-month period, of the following factors: basic fibroblast growth factor (bFGF, n = 6), vascular endothelial growth factor (VEGF, n = 6), and regenerating agent (RGTA, n = 6). Six sheep injected with phosphate-buffered saline (used for dilution of the growth factors) were used as a control group. At 3 months, angiographic, histologic, and histomorphometric studies were performed. RESULTS: Angiographic studies of the animals treated with growth factors demonstrated hypervascularization due to the development of new vessels. Histomorphometric and histologic studies showed a significant increase in the number of capillaries and arterioles (100 fields/muscle) in the groups treated with bFGF (443.0 +/- 101.2, p < 0.01), RGTA (293.2 +/- 29.3, p < 0.05), and VEGF (246.5 +/- 45.9, p < 0.05), as compared with the control group (81.5 +/- 11.4). A significantly lower atrophy score was observed in the groups treated with bFGF (1.4 +/- 0.18, p < 0.05), RGTA (1.59 +/- 0.17, p < 0.05), and VEGF (1.96 +/- 0.14, NS), as compared with the control group (2.48 +/- 0.16). CONCLUSIONS: Local administration at the heart/muscle interface of growth factors increases muscle vascularization and avoids muscle atrophy in an experimental cardiomyoplasty model, both of which are advantageous to the contracting LDM. The local growth factors delivery system used in this study appears efficient, easy to implant, and manipulate and safe.

Animals↗

Potential exposure to hepatitis C virus through accidental blood contact in interventional radiology.

PURPOSE: To quantify the prevalence of accidental blood exposure (ABE) among interventional radiologists and contrast that with the prevalence of patients with hepatitis C virus (HCV) undergoing interventional radiology procedures. MATERIALS AND METHODS: A multicenter epidemiologic study was conducted in radiology wards in France. The risk of ABE to radiologists was assessed based on personal interviews that determined the frequency and type of ABE and the use of standard protective barriers. Patients who underwent invasive procedures underwent prospective sampling for HCV serologic analysis. HCV viremia was measured in patients who tested positive for HCV. RESULTS: Of the 77 radiologists who participated in 11 interventional radiology wards, 44% reported at least one incident of mucous membrane blood exposure and 52% reported at least one percutaneous injury since the beginning of their occupational activity. Compliance with standard precautions was poor, especially for the use of protective clothes and safety material. Overall, 91 of 944 treated patients (9.7%) tested positive for HCV during the study period, of whom 90.1% had positive viremia results, demonstrating a high potential for contamination through blood contacts. CONCLUSIONS: The probability of HCV transmission from contact with contaminated blood after percutaneous injury ranged from 0.013 to 0.030; the high frequency of accidental blood exposure and high percentage of patients with HCV could generate a risk of exposure to HCV for radiologists who perform invasive procedures with frequent blood contact. The need to reinforce compliance with standard hygiene precautions is becoming crucial for medical and technical personnel working in these wards.

Blood-Borne Pathogens↗

Arterial percutaneous angioplasty in upper limbs with vascular access devices for haemodialysis.

BACKGROUND: The purpose of this study was to evaluate retrospectively the clinical context and effectiveness of arterial percutaneous transluminal angioplasty (PTA) of arterio-venous fistulae in chronic haemodialysis patients. METHODS: Between May 1992 and June 1997, arterial PTA was performed in 33 patients with a total of 35 angioaccess devices of the upper limbs (18 arterio-venous fistulae and 17 PTFE grafts). Clinical indications for arterial PTA were unexplained acute thrombosis in 12 patients (34.3%), insufficient blood flow in 13 patients (37.1%), and severe limb ischaemia in 10 patients (28.6%), two of whom had skin ulcerations and one had severe neurological damage. Follow-up periods varied between 1 and 55 months (mean 15.5 months). RESULTS: PTA was attempted in 22 radial, 10 brachial and seven ulnar arteries. Angioplasty was successful (i.e. residual stenosis of </=30%) in all but one patient. There were no complications. Early re-thrombosis (<1 month) occurred in two of the 12 patients with acute occlusions. All the angioaccesses of patients with insufficient blood flow were improved. Eight of the patients with limb ischaemia became symptom free, and two were failures (one had partial healing of skin ulcerations and one did not improve). Re-stenosis occurred in six cases (27.3% of the 22 angiograms performed) but re-dilatation was performed in only two instances. Primary and secondary patencies were 63.5 and 90.6% at 6 months and 40.8 and 75.6% at 24 months, respectively. CONCLUSION: Chronic arterial lesions in upper limbs bearing vascular access devices for haemodialysis may lead to thrombosis, ischaemia and insufficient flow for dialysis treatment. PTA is a safe and effective technique with a low rate of re-intervention.

Adult↗