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Biomedical subjects

R Limet

Publications and source records attributed to R Limet.

At least 109 records · Page 6Linked to original sources

Routine ultrasound screening for abdominal aortic aneurysm among 65- and 75-year-old men in a city of 200,000 inhabitants.

Unruptured abdominal aortic aneurysm (AAA) is seldom recognized. Thus it is difficult to know whether the incidence of AAA in the general population is high enough to warrant routine screening at least in men after a certain age. Ultrasound screening studies to evaluate the incidence of AAA have been carried out in several English-speaking and Scandinavian countries. The purpose of this report is to describe the results of a study carried out in Belgium. All 65- and 75-year-old men living in the city of Liege, Belgium, were given the opportunity to undergo a free ultrasound examination. Only 41% of the target population was examined. AAA defined as abdominal aortic diameter of >30 mm was observed in 28 subjects (incidence: 3.8%). Mean abdominal aortic diameter was 34.7 mm. A diameter >29 mm was observed in 33 subjects (incidence 4.5%). Mean abdominal aortic diameter was 30.4 mm. On the basis of epidemiological data collected, a high-risk population for AAA was identified. Arterial hypertension (p < 0.05), previous coronary artery surgery (p < 0.05), and smoking (p < 0.06) were more common in subjects with than without AAA. The overall cost of screening was $18.175. The cost per AAA diagnosed was $551.00.

Aged↗

Effects of PEEP on systemic venous capacitance.

The aim of the present study was to determine effects of positive end expiratory pressure (PEEP) application on peripheral venous capacitance and relate them to concomitant central hemodynamic disturbances. The venous volume-pressure (V/P) relationships were studied in 6 intact anesthetized pigs to describe the effects of PEEP on systemic venous compliance (computed as the slope of the V/P relationship) and unstressed volume (referred to as the extrapolated volume intercept). Cardiac volumes as well as partitioning of circulating blood volume between central (ITBV) and peripheral (PBV) compartments were assessed by thermo-dye dilution techniques. During a 15 cm H2O PEEP application, venous compliance was reduced by 48%, while unstressed volume was increased by 25% and peripheral blood pooling increased from 63 to 74%. As a result, left heart and right ventricular end diastolic volumes were decreased by 8% and by 44%, respectively. It is concluded that increased venous unstressed volume and reduced compliance depicted the distension of the venous tree secondary to PEEP which acted as an impediment to venous return. As a consequence, cardiac output was reduced because of decreased preload.

Animals↗

[The clinical case of the month. Apropos of a case of unexplained fever].

An episode of fever of prolonged duration and undetermined origin always remains a difficult clinical problem. Several etiologies can indeed be responsible. If one wishes to obtain a diagnosis of the origin of the fever, one should adopt a well-structured strategy in which the various investigations are carried out in a strictly determined hierarchical order. This is badly needed if one wishes to reach a clue to the diagnosis and be able to implement an adequate therapy. In spite of all this, some cases will remain without precise diagnosis. The treatment of those cases will primary be empirical.

Aneurysm, Infected↗

[Cardiac assistance using transformed striated skeletal muscle: cardiomyoplasty].

The biomechanical potential of transformed skeletal muscle used for cardiocirculatory assistance is the keystone of this surgical concept. This underscores the necessity to modulate type II to type I transformation to premise the muscle bulk, shortening velocity, and, therefore, power. It is only if an efficient autologous engine is available that optimal surgical configuration (i.e. aortomyoplasty) will provide active cardiocirculatory support.

Aorta↗

[From the study of biochemical changes in ischemic and reperfused skeletal muscle to the controlled reperfusion of limbs in patients with acute severe ischemia].

The reperfusion of a limb which has been submitted to a severe and prolonged period of ischemia may be followed by dramatic local and systemic complications. The results of several experimental studies have given insights on the biochemical and physiopathological alterations occurring in the ischemic and reperfused skeletal muscle. Therefore the technique of the controlled limb reperfusion has been developed. we present the results obtained in two patients with this technique. Two patients were admitted for a limb-threatening ischemia consecutive to embolism. After removal of the thrombi with a Fogarty's catheter and before reperfusion with the normal blood, a controlled limb reperfusion was performed by mixing the systemic blood with a crystalloid solution in order to obtain a hyperosmolar, hypocalcemic, alcalotic and substrate-enriched (aspartate and glutamate) reperfusate. This reperfusate was infused during 30 min with a roller pump into the deep and superficial femoral arteries. The delivery conditions (temperature, flow and reinjection pressure) were closely monitored. In both cases, no post-operative complication was observed and the pedal pulses were restored after the operation. Complete recovery of the motor and sensitive functions were observed and the patient were discharged at the 10th post-operative day.

Acute Disease↗

Intermediate follow up of the TEKNA bileaflet valve.

BACKGROUND AND AIM OF THE STUDY: The study aim was to collect intermediate clinical data on the TEKNA bileaflet valve. METHODS: This nine-center clinical study involved 884 patients implanted between June 1990 and October 1993. The population consisted of 522 (59.0%) males and 362 (41.0%) females. Mean age at implant was 59.1 +/- 11.8 years (range: 14.7 to 88.4 years). Indication for valve replacement was dependent on the position: stenosis was the predominant reason in the aortic position; regurgitation was more pronounced for the mitral position. A total of 261 (29.5%) patients underwent concomitant procedures. Mean follow up is 2.7 +/- 1.2 years; total follow up is 2386.1 patient-years (pt-yr). RESULTS: Total operative (< or = 30 days postoperative) mortality rate was 3.7%; seven patients (0.8%) died due to valve-related causes. Total postoperative (> 30 days postoperative) mortality rate was 2.5%/pt-yr and included a valve-related mortality rate of 1.1%/pt-yr. The following valve-related complication rates (%/pt-yr) were reported for the long-term postoperative period: thromboembolism 0.6; valve thrombosis 0.3; bleeding events 1.5; non-structural deterioration 0.6; and endocarditis 0.4. No structural valve deterioration was reported. Actuarial freedom at four years was: overall survival rate 86.9 +/- 1.4%; valve-related survival rate 94.7 +/- 1.0%; freedom from thromboembolism 96.8 +/- 0.9%; valve thrombosis 99.3 +/- 0.3%; endocarditis 98.5 +/- 0.5%; bleeding events 94.3 +/- 1.0%; and non-structural deterioration 98.2 +/- 0.6%. CONCLUSIONS: The data indicate that observed mortality is due mainly to non-valve-related disorders. Risk of thromboembolic and bleeding events was low (0.9%/pt-yr and 1.5%/pt-yr, respectively). We conclude that this valve is safe and efficacious for use.

Actuarial Analysis↗

[Vascular surgery in octogenarians].

The prevalence of peripheral vascular disease increases with aging of the population. About 8% of the octogenarians present significant carotid artery stenosis, about 4% have an abdominal aortic anneurysm of 40 mm or more, and 6% suffer critical limb ischemia. Carotid endarterectomy in octogenarians is a valuable tool for stroke prevention, only if the combined perioperative stroke-mortality rate is lower than 3%. Operating an abdominal aneurysm of 50 mm or more in octogenarians is characterized by an operative mortality that is higher compared to that observed in a younger patient group (4.7% vs 2.7%). Aneurysm-surgery remains nevertheless justified, since it is the only way to prevent the evolution to rupture, that is almost fatal. Limb salvage surgery should always be considered for an 80-years patient with critical limb ischemia, since readaptation after major limb-amputation is not evident for octogenarians. An extensive review of literature is presented concerning vascular aging and results of carotid surgery, aneurysm repair and lower limb revascularization in octogenarians. The authors report their own recent experience with carotid surgery and aneurysm repair in patients aged 80 years or older.

Aged↗

[Clinical case of the month. Metastatic endocarditis: clinical observation and review of the literature].

The authors describe a case of metastatic endocarditis associated with a gastric carcinoma. The diagnosis was made early and the treatment by surgery and chemotherapy allowed a survival of 18 months, which is unusually long. The differential diagnosis is discussed and includes nonbacterial thrombotic endocarditis, infectious endocarditis and primary tumors of the heart.

Adenocarcinoma↗

Advantages of inferior vena caval flow preservation in combined transplantation of the liver and heart.

Only a few cases of combined liver and heart transplantation have been reported in the literature, and no standard surgical procedure has yet been established. We report the successful transplantation of both liver and heart in a 28-year-old patient suffering from homozygous beta-thalassemia. We used Belghiti's technique of inferior vena caval flow preservation for liver transplantation, which avoids inferior vena cava occlusion by a side-to-side caval anastomosis. Applied to combined liver and heart transplantation, preservation of caval flow during liver transplantation may allow early discontinuation of cardiopulmonary bypass and, thus, minimize the general consequences of prolonged bypass.

Adult↗

Successful controlled limb reperfusion after severe prolonged ischemia.

Controlled limb reperfusion was performed in two patients who were admitted for lower limb-threatening ischemia as a result of embolism. After embolectomy, the inflow blood was drained with a cannula and mixed with a crystalloid solution to obtain an hyperosmolar, hypocalcemic, alkalotic, and substrate-enriched (aspartate, glutamate) reperfusate. This reperfusate was reinjected with a roller pump for 30 minutes through two cannulas inserted in the profunda and superficial femoral arteries. Temperature, intraarterial pressures, and flow were closely controlled. No complications occurred, and complete recovery of motor and sensory functions were observed, with restoration of pedal pulses.

Aged↗

Cardiac risk assessment before vascular surgery: a prospective study comparing clinical evaluation, dobutamine stress echocardiography, and dobutamine Tc-99m sestamibi tomoscintigraphy.

Preoperative evaluation for cardiac risk assessment before peripheral vascular surgery remains controversial. Between January and June 1994, a prospective open study was carried out in 156 patients scheduled for elective vascular procedures (63 carotid endarterectomies, 34 abdominal aortic aneurysms, 29 aortoiliac and 30 infrainguinal reconstructions) to compare the ability of clinical data, dobutamine stress echocardiography, and dobutamine Tc-99m sestamibi tomoscintigraphy to predict postoperative cardiac events. Pharmacological stress testing consisted of incremental dobutamine infusion (+/-1 mg atropine to achieve 85% of age-predicted maximal heart rate, with continuous echocardiographic monitoring, and injection of Tc-99m sestamibi after dobutamine infusion). Dobutamine echocardiography was abnormal in 36 patients (worsening resting wall motion abnormality in 11; new induced wall motion abnormality in 25). Dobutamine Tc-99m sestamibi tomoscintigraphy revealed a reversible perfusion defect in 34 patients, indicating the presence of myocardial ischaemia. As a result, eight patients underwent myocardial revascularization (n = 5) or the proposed operation was cancelled (n = 3). In the remaining 142 vascular procedures, there were eight (5.6%) adverse cardiac events: three myocardial infarctions (two fatal), three prolonged myocardial ischaemia, one acute congestive heart failure and one sustained ventricular arrhythmia in the post operative period. Univariate analysis selected unstable angina (relative risk (RR) 11.6), previous congestive heart failure (RR 6.4), Detsky's score of > or = 15 (RR 3.0), positive dobutamine stress echocardiography (RR 3.7), and positive dobutamine tomoscintigraphy (RR 7.4) as significant predictors of postoperative cardiac events. In patients without clinical markers of coronary artery disease (n = 66), non-invasive cardiac testing did not predict cardiac complications (n = 2; one prolonged myocardial ischaemia; one infarction). In the subset of 76 patients with definite clinical or electrocardiographic evidence of ischaemic heart disease, dobutamine stress testing provided additional information, and optimized risk stratification: five of six patients who suffered a cardiac complication had a pathologic dobutamine stress test. Furthermore, a negative dobutamine stress test was characterized by a high negative predictive value (0.96 for echocardiography; 0.97 for tomoscintigraphy). The study further demonstrated that the cardiac response (ischaemic versus non-ischaemic) to dobutamine stress was concordantly classified by echocardiographic and tomoscintigraphic techniques in 96% of cases. It is concluded that complementary non-invasive cardiac stress testing by dobutamine is indicated only in patients with clinically apparent coronary artery disease.

Aged↗

Comparison of results of carotid artery surgery after either direct closure or use of a vein patch.

In order to assess the benefit of vein patching versus direct closure after carotid endarterectomy, a series of 2271 carotid operations were analysed retrospectively. Apart from 114 procedures consisting of saphenous vein bypass (n = 29) and eversion endarterectomy (n = 85), 2157 open endarterectomies were performed. They were closed either directly (n = 837) or using a vein patch (n = 1320). The combined mortality-major neurological morbidity rate was 1.7%, i.e. 1% mortality (0.2% neurological) and 0.7% permanent neurological morbidity (0.5% ipsilateral to the operated artery). Early symptomatic internal carotid thrombosis was documented in six cases (four following direct closure and two after vein patching). A total of 827 carotid arteries were followed up by duplex scanning on an annual basis (244 direct closure and 583 vein patching). The mean follow-up was 44 months; 69 months for direct closure and 35 months for vein patching. In direct closure, there were 21 stenoses (9%) and 10 occult thromboses (4%); in vein patching carotids, there were 17 stenoses (3%), nine thromboses (1.8%) [corrected] and six pseudoaneurysms (1%). Annual incidence of poor results was 2.4% in direct closure, and 0.87% in vein patching. The only other factor responsible for a significant difference was gender (3.4% in women versus 2.1% in men). In this retrospective study, vein patching appears to be beneficial for the prevention of acute postoperative thrombosis and late stenosis or thrombosis.

Aged↗

Biomechanical characteristics of unconditioned and conditioned latissimus dorsi muscles used for cardiocirculatory assistance.

An understanding of the biomechanical characteristics of striated skeletal muscles involved in cardiocirculatory assistance is a prerequisite to assess their efficacy and to evaluate their haemodynamic benefits. Six goats had their latissimus dorsi muscles evaluated by isometric strain gauge testing. Total tension, and both active and passive force development at different preloads were measured. The relationship between muscle impedance and starting length was also studied. Four additional muscles were submitted to isometric and isotonic strain gauge testing after 3 months of chronic electrical stimulation (Broussais Hospital protocol) with the contralateral muscle serving as a control. In isometric testing, both conditioned and unconditioned goat latissimus dorsi displayed a Frank-Starling length-tension curve, and a linear relationship between muscle impedance and starting length was found. Chronic stimulation preserved muscle mass and isometric force. Transformed muscles showed a mean 59% reduction of maximal shortening velocity; means (s.d.) residual shortening velocity at maximal work and power output was 0.17(0.07) m/s. The work and power output were both reduced 65% after stimulation, and the residual maximal power at optimal preload varied from approximately 7.7 and 9.6 W/kg. It is concluded that, following the Broussais protocol, the goat latissimus dorsi muscle retained mass and most of its isometric force-generating capacity, but lost significant work and power potential. The residual power output did not, however, preclude the possibility of a significant cardiocirculatory contribution, providing that the conditions for optimal energy transduction are adequately delineated.

Animals↗

Fatal mural endocarditis and cutaneous botryomycosis after heart transplantation.

Fatal mural endocarditis and botryomycosis occurred concurrently in a 62-year-old women 4 months after orthotopic heart transplantation. Subsequent to mild mitral regurgitation, infection developed on a left atrial thrombus and was complicated by cerebral embolization. Simultaneously, skin nodules manifested on both forearms. Histologic examination revealed typical aspects of early evolving botryomycosis with massive infiltration of the dermis and hypodermis by necrotic granulomas framed by grains of Gram-positive coccoid forms. Bacteria were decorated by a nonspecific polyclonal antibody to Mycobacterium bovis.

Endocarditis, Bacterial↗

Clear cell sarcoma: an extremely rare cause of pleural disease.

We present the case of a 36 yr old woman with a persisting complaints of left chest pain. A chest radiograph revealed multiple left pleural thickenings. Classical exploration was negative. Thoracic surgery allowed the subtotal removal of a huge pleural tumour. The histological examination revealed a clear cell sarcoma. The literature on this extremely rare tumour is reviewed.

Adult↗