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Biomedical subjects

R Limet

Publications and source records attributed to R Limet.

At least 343 records · Page 19Linked to original sources

Abdominal aortic aneurysm.

Abdominal aortic aneurysms cause 1.3% of all deaths among men aged 65-85 years in developed countries. These aneurysms are typically asymptomatic until the catastrophic event of rupture. Repair of large or symptomatic aneurysms by open surgery or endovascular repair is recommended, whereas repair of small abdominal aortic aneurysms does not provide a significant benefit. Abdominal aortic aneurysm is linked to the degradation of the elastic media of the atheromatous aorta. An inflammatory cell infiltrate, neovascularisation, and production and activation of various proteases and cytokines contribute to the development of this disorder, although the underlying mechanisms are unknown. In this Seminar, we aim to provide an updated review of the pathophysiology, current and new diagnostic procedures, assessment, and treatment of abdominal aortic aneurysm to provide family practitioners with a working knowledge of this disorder.

Aortic Aneurysm, Abdominal↗

Intrinsic structural failure of polyester (Dacron) vascular grafts. A general review.

Intrinsic structural failure of Dacron prostheses is a late exceptional complication, resulting from a loss of structural integrity of the graft. The authors report six cases of non-anastomotic false aneurysms in the mid-portion of a vascular Dacron graft, observed at a mean of 12 years after insertion. It concerns four femoro-popliteal bypass grafts, one cross-over graft and a branch of a bifurcated aorto-bifemoral graft, implanted between 1980 and 1990. This represents 0.2% of all vascular Dacron grafts implanted in authors' department since 1980. The degenerated prosthesis was excised, and a new bypass graft was inserted. In three cases, histological analysis revealed a foreign body giant cell reaction against fragmented Dacron fibers. In none of the cases there was evidence of graft infection. The authors discuss the evidence and etiopathogeny of this late, unusual complication, inherent to the Dacron graft material. The most probable causative factor is material fatigue, leading to gradual breakdown and fragmentation of individual fibers, and subsequent biodegradation of the basic material. Such an intrinsic weakness of prosthetic fabric has only be observed in first and second generation Dacron grafts.

Aneurysm, False↗

The usual causes of left ventricular outflow tract obstruction below the aortic valve in normal ventriculoarterial connection: review of the physiopathology and surgical implications.

Subaortic narrowing leading to left ventricular outflow tract obstruction (LVOTO) is a significant pathology that may be encountered pre- or postoperatively in both acquired or congenital cardiac disease. Through a review of the morphological features and mechanisms in the different clinical situations, the anatomic, dynamic and mixed forms of subaortic obstruction are emphasized. Knowledge of the substrate of LVOTO, its physiopathology and natural history allows to plan accordingly the surgical repair and the postoperative management.

Aortic Stenosis, Subvalvular↗

Outlook of non operated type B aortic dissection with special reference to the incidence of degenerative abdominal aortic aneurysm (AAA). One center study.

OBJECTIVES: to determine the value of pharmacological treatment of type B aortic dissection (B AD) in face of new forms of treatment. DESIGN: this is a retrospective study of the period from 1990 to 2000. Files of 81 patients have been reviewed and completed by questionnaires. RESULTS: Two B AD died after admission without any treatment, 10 were operated on with 7 discharged alive (group I); 69 received hypotensive agents and beta-blockers, 65 were discharged alive (group II). Late mortality of the group I is 3/7, not related with B AD. Late mortality after mean follow-up of 56.8 months is 27/65 with 4/27 related to B AD (4 ruptures, 2 operated on). Non fatal secondary surgery amounts 5 in 4 patients. Total B AD aortic events comprise 8/65 patients. Type A AD were operated on successfully (8 : 4 before B AD, and 4 after B AD). Degenerative abdominal aortic aneurysms were present, operated (9) or not (3), in the history of patients and 3 more appear subsequently. At 10 years, actuarial survival is 40% +/- 18. CONCLUSION: in non-complicated cases of B AD, medical treatment is a reasonable choice, provided that a strict follow-up of the thoracic abdominal aorta is performed.

Adrenergic beta-Antagonists↗

Potential benefits of laparoscopic aorto-bifemoral bypass surgery.

BACKGROUND: This series aims to prove the positive impact of laparoscopic approach in aortofemoral bypass grafting. METHODS: It concerns a retrospective non randomized study comparing 58 consecutive patients treated with laparoscopic procedure (n = 30) and with a standard open procedure (n = 28) in a single center. The different operating times, the complications and the follow-up of these two groups are compared RESULTS: The demographics and angiographic data of the two groups were comparable. Operating time was longer in the laparoscopic group. However, we noticed a significant shorter hospitalisation stay (p < 0.0001) after the laparoscopic procedure with a mean 5.1 days. There was no significant difference of morbidity. CONCLUSION: We suggest that the trans-peritoneal approach is the best way in laparoscopic procedure in term of exposure and ergonomics. Laparoscopic aortofemoral bypass grafting is feasible, safe and effective. Shortening of operating time is observed as surgeon's experience grows.

Anastomosis, Surgical↗

Lessons learnt from carotid artery trials.

The objective of the authors is to assess the natural history of carotid artery disease and the role of carotid intervention in preventing ipsilateral stroke. The development of endovascular techniques for correction of carotid artery stenoses made this less invasive technique very popular, with an inherent risk of unregulated overuse by a variety of medical specialists, who are not always well informed on the natural history of carotid artery disease. It re-opened the discussion on the value of carotid endarterectomy for stroke prophylaxis. This ongoing debate offers the opportunity to distil evidence-based guidelines for the management of extracranial carotid artery stenoses. In recent papers, some authors expressed doubts on the validity and general applicability of the results of the pivotal randomised trials of carotid endarterectomy. The excellent results in terms of operative outcome and long term stroke prevention would, according to certain comments, not be attainable in routine practice. Another criticism of carotid endarterectomy is its higher operative morbidity in terms of cranial nerve lesions and myocardial infarctions, compared to endovascular procedures. This consideration is, for some authors, the main reason to espouse carotid artery stenting as a better alternative to carotid endarterectomy. Any evidence supporting this point of view is missing. The supposed equivalence or non-inferiority of carotid artery stenting is purely speculative. The aim of this review paper is to summarize the crude data of carotid surgery trials. The authors aim to answer four questions. For which lesions is carotid endarterectomy most beneficial ? Are the results of randomised carotid surgery trials biased by the selection of patients ? Is operative morbidity, other than stroke, under-estimated ? Is carotid artery stenting safe and efficacious ? An in-depth review with a critical analysis is made of recently published and on-going trials, comparing carotid surgery with percutaneous carotid angioplasty.

Carotid Stenosis↗

Surgical technique for cardiomyoplasty and iterative transthoracic biopsies in an experimental goat model.

Cardiomyoplasty is a new surgical procedure using transformed skeletal muscle to reinforce or substitute for the myocardium. For the purpose of studying surgical technique and investigating basic questions, we have developed a model of reinforcement cardiomyoplasty. Herein, we describe anesthetic management, surgical technique, and the technique for iterative transthoracic biopsies. This model has proven to be valuable in several long-term studies involving more than 30 goats. Preliminary data to ascertain the efficacy of the proposed technique are provided.

Anesthesia↗

[Determination of plasma concentrations of antioxidants, antibodies against oxidized LDL, and homocysteine in a population sample from Liège].

A large number of epidemiological and clinical studies suggest that oxidative stress plays an important role in the development of cardiovascular diseases. In this way, following reference values in plasmatic antioxidants have been determined in a group of 123 blood donors (94 males, 29 females; age: 21-64 years) living in the surroundings of Liege, Belgium: vitamin A (1.5-3.62 mmol/l), vitamin C (3.68-75.21 mmol/l), vitamin E (16.98-46.46 mmol/l), ratio vitamin E/cholesterol (3.92-8.32 mmol/mmol), selenium (0.66-1.26 mmol/l), sulphydryl proteins (216-556 mmol/l), uric acid (174-477 mmol/l), superoxide dismutase (542-852 IU/g hemoglobine), glutathion peroxidase (39.55-91.83 IU/g hemoglobine). Only a few number of subjects were found with values corresponding to high risk of deficiency in antioxidants although low values in vitamin C (< 11.35 mmol/l) and in selenium (< 0.75 mmol/l) were respectively observed in 5.69 and 10.5% of our subjects. Autoantibodies against oxidized LDL, as marker of oxidative stress, and homocysteine, as a risk factor of atherosclerosis involved in the development of oxidative stress, have also been investigated. Approximatively 40% of the population presented values higher than the superior limit mean value (20.3% > 650 IU/l in autoantibodies and 19.5% > 15.2 mmol/l in homocysteine) that are, however, not correlated with age or low levels in antioxidants. The effect of smoking (25% of the population) contributed to significantly decrease vitamin C, selenium and glutathion peroxidase concentrations by 31.9 and 13% when compared to nonsmokers. Intake of 1 to 4 fruits per day resulted in a significant increase of 56.9% in vitamin C when compared to nonconsumers (26.8% of the population). In contrast, homocysteine concentrations were significantly decreased by 21.4% in fruits consumers. Thank to the development of methods allowing the routine dosage of all these parameters, general practitioners can now easily establish the oxidative stress status of their patients and, as fonction of getting patterns, detect populations at risk of developing cardiovascular diseases.

Adult↗

Rupture of a thoracic aneurysm in the left bronchus.

Aortobronchic fistula is a very unusual complication of thoracic aneurysm. We report the case of a 71-year old man with rupture of a thoracic aortic aneurysm in the left main bronchus. The patient had suffered a car crash fifteen years ago, without any evidence of aortic rupture at the time. Thereafter, he developed an aortic isthmic dilation (36 mm in diameter). The patient suffered from long standing pulmonary insufficiency and emphysema and was admitted several times on an urgent basis for acute dyspnea. During an hospitalization for respiratory distress, he presented haemoptysis and left lung hyperinflation secondary to partial fistulization and extrinsic compression of the main left bronchus. Isthmic aortic resection and prosthetic grafting was performed and the left main bronchus was closed by an autologous pericardial patch. Ten days later, following an air-leak from the bronchial closure, a transposed latissimus dorsi flap was used by the plastic surgeon to repair the defect. Nevertheless, the patient died from multisystemic failure six weeks later.

Aged↗

Amputations in diabetic patients: a plea for footsparing surgery.

The authors observed a rather high rate of primary major amputation (above-knee or below-knee) performed for diabetic foot problems as well as an important revision rate for minor amputations (forefoot or toe) in diabetics. They reviewed their experience in order to compare it with more recent data from the literature, pleading for foot-sparing surgery. From 1993 to 1998, 186 amputations were performed on 146 diabetic patients. The cause of foot ulcers was neuropathy in 43 of them (51 episodes of diabetic foot problems) while in the remaining 103 patients (135 episodes of diabetic foot problems), diabetic macroangiopathy (absent ankle pulses) was on cause. For neuropathic foot problems, amputations were almost minor, resulting in a limb salvage rate of 90%. Only five of these patients (12%) had primary major limb amputation versus 43 of the dysvascular patients (42%). The reasons for major amputation by first intention were extensive tissue loss, intractable infection or non-reconstructible occlusive vessel disease, as judged by the surgeon. A foot-sparing surgery was attempted in 92 dysvascular cases. In only 44 of them, a preliminary vascular repair was performed. Twenty eight percent of the primary toe amputations and 24% of the forefoot amputations required secondary revision to a more proximal level. Minor amputations in case of diabetic neuropathy were characterized by a more favourable outcome: only 14% of the toe and 9% of the forefoot amputations failed. During follow-up, only 63% of the major amputations regained an autonomic walking capability with their prosthesis. Wound healing problems in diabetic foot are mainly due to infection and poor tissue perfusion. An aggressive control of the infection and distal revascularization of calf- or foot arteries, whenever possible, could improve the results of diabetic foot surgery. The poor functional recovery after major amputation (only 63% autonomic gait with limb prosthesis) argues for foot-sparing surgery whenever possible.

Aged↗

Nicardipine protocol for CABG using the radial artery clinical and angiographic data.

The routine use of arterial grafts in coronary surgery is facilitated by peroperative adjunction of antispasmodic drug to reduce the event of spasm. Diltiazem has been favoured in most clinical studies devoted to the radial artery graft. The aim of this study was to assess the efficacy of a spasm preventing protocol associating hydrostatic dilation of the graft with a diluted solution of papaverine and nicardipine infusion, starting preoperatively and continued postoperatively in i.v. and per os forms. Between September 1996 and March 1997, a consecutive series of 50 patients underwent myocardial revascularization using the radial artery. The radial artery was prepared by hydrostatic dilation with papaverine (1%) and nicardipine was administrated at 0.25 microgram/kg/min and titrated according to the arterial systemic pressure. Operative mortality was 4% (sepsis). There was no evidence of perioperative MI nor hypoperfusion syndrome. Mean CKMB level at 18 hours was 36 micrograms/l. No ischaemic anomalies of the ECG were detected. Angiography performed in the last 20 patients showed a 98% (51/52) permeability rate for all graft; 19/20 radial grafts (95%) were patent. One radial graft presented a 50% stenosis at the proximal anastomosis, and another a moderate spasm (40%) in the middle part of the conduit. This study confirms that the radial artery conduit can be used with satisfactory results for routine coronary artery bypass. The use of nicardipine allows the control the vasoreactivity of the radial graft without totally obviating at least angiographic spasm. This drug is easy to titrate, and well tolerated in association to beta-blockers in the routine perioperative management of the coronary patients.

Coronary Angiography↗

Chronic ischaemic gastritis: an unusual form of splanchnic vascular insufficiency.

Three cases of erosive gastroduodenitis secondary to chronic splanchnic vascular insufficiency are reported. In all cases, pain failed to respond to conventional therapeutic measures for peptic ulcer disease. A patchy discolouration and erythematous mottling of the gastric mucosa, with scattered shallow aphthous ulcers, was seen on endoscopic examination. Angiography showed coeliac axis involvement in all patients, with insufficient mesenteric collateral pathways. Chronic gastritis resolved clinically and endoscopically after revascularization.

Aged↗

Pathological aspects of carotid plaques. Surgical and clinical significance.

We examined 134 carotid plaques microscopically in 125 consecutive patients, and found 21 (15.7%) had simple fibrous plaques versus 113 (84.3%) complicated plaques. The following plaque characteristics were present: intraplaque hemorrhage (73 plaques), ulceration (83 plaques), fresh thrombus (93 plaques), and recanalized thrombus (22 plaques). An average of 2.4 characteristics were observed in each complicated plaque. The only significant (p less than 0.05) clinico-pathologic correlation was the presence of fresh thrombi, found in 80% of the plaques from patients with a previous transient ischemic attack, in 93% of those with nonfocal neurologic symptoms, and in 80% of those with amaurosis fugax. Analysing the localization of the fresh thrombus (mural or intraluminal), we found that fresh thrombus in symptomatic plaques was most frequently (NS) (71 to 77%) exposed to the vessel lumen. Ulceration without fresh thrombus, plaque hemorrhage and recanalized thrombus were also found in a considerable number of asymptomatic patients, of whom 85% (33/41) presented a form of complicated plaque.

Adult↗