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Biomedical subjects

J C Gaux

Publications and source records attributed to J C Gaux.

At least 19 recordsLinked to original sources

[Endovascular treatment of sclerotic arteriopathies of the lower limbs].

Percutaneous transluminal angioplasty is performed to treat arterial stenoses or occlusions. Currently, balloon angioplasty is still considered as the gold standard even if new interventional devices and techniques have been proposed to improve immediate and long-term results: stents, intraarterial thrombolysis, percutaneous aspiration embolectomy, atherectomy, laser and ultrasound angioplasty. Evaluations of these methods in the treatment of peripheral arterial diseases are ongoing. An interventional procedure is indicated only after a thorough analysis of the medical and anatomo-angiographic data. A stenosis or a short occlusion of the iliac or the femoro-popliteal arteries are typical indications for percutaneous angioplasty in case of claudication; more complex lesions become gradually accessible to percutaneous methods in patients with chronic critical and even acute arterial ischaemia of the lower limbs. During the follow-up, the development of a restenosis is detected by careful clinical examination and ultrasound duplex scanning.

Acute Disease

Strecker stent implantation in iliac arteries: patency and predictive factors for long-term success.

PURPOSE: To evaluate Strecker stent implantation in iliac arteries. MATERIALS AND METHODS: Sixty-four iliac arteries with Strecker stents were prospectively studied. Stents were placed for dissection (n = 31), total occlusion (n = 28), unsatisfactory results (n = 3) or restenosis (n = 1) after percutaneous transluminal angioplasty, and a calcified atherosclerotic lesion that bulged into the lumen (n = 1). RESULTS: Stent placement was successful in 63 arteries (98%). The overall complication rate was 12% (n = 8). During follow-up, three patients died. The stent was compromised in 18 cases because of hyperplasia (n = 10) or occlusion (n = 8). The primary patency rate was 84% at 1 year and 69% at 2 years; the secondary patency rate was 90% at 1 year and 81% at 2 years. Initial dissection (P = .046), a length of 60 mm or less for the stent region (P = .007), and total covering of the abnormal segment with the stent (P = .03) were significant predictive factors for good, long-term results. CONCLUSION: Use of the Strecker endoprosthesis appears useful but not ideal. Determination of predictive factors for long-term success may help identify indications for its use.

Aortic Dissection

[MRI in cardiology: clinical applications and perspectives].

MRI is an effective tool in the evaluation of cardiovascular diseases. With continued improvements in MR angiography, velocity mapping, myocardial tagging, imaging speed and display, it is anticipated that MRI will play an ever-increasing role in the morphological evaluation of many cardiovascular anomalies. The need for quantification in cardiology has led to the development of a variety of techniques to assess cardiac size and function. In attempting to answer these clinical questions, MRI provides major advantages several: extraordinary flexibility, powerful contrast mechanisms, sensitivity to flow and motion, and freedom from ionizing radiation, contrast agent and acoustic windows. Because of accurate initial results in quantifying cardiac chamber size, global and segmental function, it is likely that MRI methods will play an increasing role in the evaluation of cardiac structure and function. Recently, MRI has emerged as an important tool in the evaluation of great vessel disease, particularly in the evaluation of both congenital and acquired abnormalities of the aorta. Early evidence suggests that magnetic resonance may help in distinguishing constrictive pericarditis from restrictive cardiomyopathy (e.g., amyloid heart disease). Cardiac-MRI lends itself to assessment of intracardiac masses. Spin-echo imaging alone is often sufficient for diagnosis. Cine-MRI has important additive value, however, when a mass lesion shows dynamic motion, or when abnormal flow patterns in conjunction with a mass lesion require evaluation.

Echocardiography

[Drug thrombolysis and mechanical recanalization in recent femoro-popliteal arterial occlusions].

Acute femoro-popliteal occlusions (native arteries or bypass grafts) were treated by medical and surgical treatment. Despite improvement in surgical technique, patient mortality was high and limb loss remained frequent. Percutaneous endoluminal treatment of such lesions is feasible using in situ fibrinolysis and/or thromboaspiration singly or in association with balloon angioplasty. Those techniques are effective and are currently the first intention treatment of many of those acute femoro-popliteal occlusion. The advantages and disadvantages of those techniques are discussed, as well as their respective indications, and particularly their place compared to surgical techniques. New devices such as mechanical thrombectomy may increase effectivity and indications of endovascular treatment however such devices need to be better evaluated.

Arterial Occlusive Diseases

Determination of left ventricular mass with electron beam computed tomography in deformed, hypertrophic human hearts.

This study firstly determined the accuracy of left ventricular mass (LVM) determination by electron beam CT in normal and distorted human cadaver hearts, and secondly the in vivo reproducibility of these measurements, in normal subjects and patients with various cardiac diseases, over a wide range of LVM (104-631 g). In cadaver hearts, there was a close correlation between electron beam CT and autopsy LVM values: r = 0.97, SEE = 16 g. Intra-observer variability: results of LVM measurements obtained in cadaver hearts by observer 1 and in in vivo studies by observer 2 were y = 1.001 x -1.34, r = 0.99, SEB = 6 g and y = 0.99 x +3.78, r = 0.99, SEE = 19 g, respectively. Inter-observer variability: results in cadaver and in vivo studies were y = 1.05 x -5.94, r = 0.98, SEE = 14 g and y = 1.13 x -23, r = 0.99, SEE = 28 g, respectively. Thus, these results over a wide LVM range provide extensive validation of electron beam CT measurements in hearts with marked left ventricular distortion. This method should play a valuable role, within the scope of clinical research, in assessing left ventricular remodelling in various conditions in which echocardiographic data are inaccurate.

Adult

Stenoses of renal branch arteries in fibromuscular dysplasia: results of percutaneous transluminal angioplasty.

PURPOSE: To evaluate percutaneous transluminal renal angioplasty (PTRA) in the treatment of renal branch artery stenoses caused by fibromuscular dysplasia. MATERIALS AND METHODS: The authors retrospectively studied the files of 20 consecutive hypertensive patients with 25 branch artery stenoses associated with 10 main renal artery lesions. Results at clinical and angiographic follow-up were assessed by means of life-table analysis. RESULTS: PTRA was technically successful in 21 of the 25 renal branch artery stenoses (84%). One of the technical failures was treated by means of selective embolization. Nine of the 10 associated main renal artery lesions were successfully dilated, and the 10th was improved. Immediately after PTRA, at 6-month follow-up, and at long-term follow-up, 70%, 76%, and 68% of the patients, respectively, were cured and 25%, 24%, and 16% were improved. Stenosis recurred in 9% of the branch arteries and was associated with clinical relapse; these arteries were redilated, and all patients were considered cured at the second 6-month follow-up. CONCLUSION: PTRA should be considered the first-line treatment for hypertension due to renal branch artery stenosis in fibromuscular disease.

Adolescent

[Dynamic cardiovascular studies with electron beam computed tomography].

Electron Beam CT (EBCT) is still emerging as a new functional imaging procedure in providing high morphological studies and dynamic quantitative functional data. Morphological EBCT studies have previously proven their usefulness in pathologic conditions of the thoracic aorta, in congenital diseases, in cardiac masses or tumors... Functional studies achieved using cine mode and/or flow mode are used to assess both mobility and perfusion of structures. Such dynamic analysis have confirmed that their applications will have a major impact on the knowledge of cardiac physiology, the understanding of cardiovascular diseases, if not in daily patient care. For instance, in studies on ventricular function, among the imaging modalities in current use, EBCT is probably most accurate for the evaluation of systolic regional or global function. EBCT is a cross-sectional imaging methods which overcome an important limitation shared by most other imaging modalities, namely the superimposition of overlapping cardiac and thoracic structures. Since in the method high spatial, contrast, and temporal resolution tomography displays the myocardial wall itself, an accurate delineating of endocardial and epicardial contours in contiguous levels can be obtained. Further developments in computer-automated analysis from dynamic EBCT studies have to be carried out to gain clinical acceptance and to facilitate the routine.

Cardiovascular Diseases

[Electron canon computed tomography. Technique and clinical applications in cardiac imaging].

Electron Beam CT (EBCT) was initially devoted to both dynamic and morphological cardiac studies. ECG gated slices acquired in 100 milliseconds produce cardiac images without motion artefacts. Intracavitary tumors and thrombus are clearly detected and EBCT contributes to the stagging and follow-up of masses. Exploration of congenital abnormalities such as pulmonary atresia can be performed even in newborns. EBCT allows the diagnosis of tiny modifications of coronary arteries, endocardium or pericardium. EBCT offers a new modality of cardiac imaging which gives complementary informations to other modalities.

Coronary Disease

[Contribution of the electron beam scanner (Imatron) in aortic pathology].

Electron Beam CT (SFE, Imatron) uses electron beam to generate X rays. This allows the shortest acquisition time today available (50-100 ms). It is the best CT examination for moving structures. In vascular disease arterial wall study is the most important end point, especially in aortic pathology. EBCT is effective in aortic aneurysm, dissection and aortitis diagnosis. It allows a pre-surgical mapping of the lesion and follow-up. We believe that EBCT is superior to other diagnostic mean in the assessment of the ascending aorta and of small arterial lesions.

Aortic Dissection

Postoperative pseudoaneurysm of ascending aorta: role of ultrafast computed tomography imaging.

A 34-year-old woman, who had undergone a thoracic aortic aneurysmectomy and replacement with a prosthetic tube graft several months previously, presented with a pseudoaneurysm arising from the proximal anastomotic site. This pseudoaneurysm was studied with contrast-enhanced ultrasfast computed tomography. The exact location of the suture dehiscence was located by the presence of a contrast jet flow through the aortic wall. This case shows the feasibility of demonstrating blood flow at the entry site of a pseudoaneurysm with ultrafast computed tomography which may avoid conventional angiography.

Adult

[Percutaneous endoluminal angioplasty of the transplanted kidney. Long-term follow-up].

A hundred and ninety five percutaneous transluminal angioplasty (PTA) of a renal transplant artery were attempted before january 1st, 1990 in 151 patients. Analysis of the series was essentially based on follow-up after PTA. PTA was initially successful in 85% of the patients. Restenoses occurred in 30% of the patient. They were usually amenable to repeat PTA. Restenosis rate after repeat PTA was of 26%. The five year secondary patency rate of the renal artery was over 85%. After a successful PTA, the blood pressure, the number of antihypertensive drug per patient and serum creatinine returned to a level close to their basal value within few days and remained stable long. After an immediate failure of PTA, secondary patency rate of the renal transplant artery was over 80% at one year. Blood pressure returned to a level close to its basal value. But, that improvement was slower (1 to 6 months) and antihypertensive drug regimen and serum creatinine remained stable. We conclude that PTA is an effective treatment at long term of hypertension and of decline in renal function due to stenoses of renal transplant arteries. However PTA carried some risks and should be attempted only stenoses of renal transplants arteries cause, severe hypertension resisting to medical therapy or decline in renal function.

Adult

[Ostial stenosis of the renal arteries: treatment by angioplasty].

In a series of 50 patients (22 females, 28 males); 52 ostial renal artery stenoses were treated by transluminal balloon angioplasty. The mean age of patients was 66 years (range 36-81); mean arterial pressures were 181 mmHg for the systolic pressure and 87 mmHg for the diastolic pressure. The mean level of serum creatinine was 179 mumol/l +/- 128. An immediate success was obtained in 86.5% (residual stenosis of 26%). There were 7.6% of immediate failures and 13.5% of residual stenosis above 50%. Mortality within 1 month was observed in 2 patients. Morbidity included one aortic dissection and 5 cholesterol embolisms. After a mean follow-up of 10 months, 78% of the series were controlled: 66.6% exhibited a residual stenosis below 50%, 25.9% had restenosis and 7.4% had an occlusion of the renal artery. Since patients with ostial renal artery stenosis constitute a high surgical risk group, transluminal balloon angioplasty might be considered as an acceptable and safe alternative treatment.

Adult

[Early angiographic evaluation of coronary bypass using arterial grafts].

The aim of this study was to evaluate the early postoperative angiographic features of arterial coronary bypass grafts in 83 asymptomatic patients referred consecutively from the surgical unit. The patients aged 33 to 78 years (average 62 years) were operated between August 1989 and March 1992 and received only arterial coronary bypass grafts: 209 arteries bypassed (121 internal mammary including 10 sequential grafts, 46 radial, 36 epigastric including 4 sequential grafts and 6 gastroepiploic arterial grafts), an average of 2.4 bypass grafts per patient. Selective angiography of the arterial grafts was performed systematically between the 7th and 15th postoperative days in patients with uncomplicated recoveries. The native coronary arterial network was opacified only when a graft was "non-functional": haemodynamic (> 70%) stenosis or occlusion. 3.8% of pediculated mammary grafts were occluded. On the other hand, 16.6% of free internal mammary grafts were occluded. None of the radial artery grafts were occluded, but 8% were stenotic. Finally, 30% of epigastric and 50% of the gastroepiploic grafts were occluded. These results confirm the good function of in situ mammary artery grafts by suggest that systematic multiple arterial grafts should be used with caution. Radial artery grafts give very encouraging results which require long-term evaluation. Early postoperative evaluation of coronary arterial grafts provides important information and should be considered a routine procedure.

Abdominal Muscles

Femoropopliteal stent placement: long-term results.

Twenty-one patients who underwent percutaneous transluminal angioplasty (PTA) followed by attempted insertion of a self-expandable vascular endoprosthesis for femoropopliteal lesions were prospectively followed up for an average of 17.6 months with angiographic, Doppler ultrasound, and clinical examinations. Stents were placed bilaterally in one patient. Of the 22 lesions, 18 were total occlusions and four, stenoses. Stent placement was successful in 21 of 22 lesions. Nine occlusions occurred: four in the first 30 days and five 1-5 months after PTA. Three patients developed intrastent intimal hyperplasia that necessitated an additional percutaneous procedure. At 12 months, the patency rate without other interventions (the primary patency rate) was 49%. In patients who underwent secondary intervention (fibrinolysis, atherectomy, or PTA), the secondary patency rate was 67%, which fell to 56% after 18 months. At the end of the study, the overall rate of reocclusion was 43%. It is concluded that use of the self-expandable vascular endoprosthesis in the femoropopliteal region likely does not decrease the reocclusion rate after PTA alone. Its use is indicated for treatment of acute closures after femoropopliteal PTA.

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