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Biomedical subjects

R Dorent

Publications and source records attributed to R Dorent.

At least 55 records · Page 3Linked to original sources
PubMed1997

Position-related factors in mitral and tricuspid bioprostheses degenerative changes.

We report clinicopathological findings in 15 patients in whom the same bioprosthesis (BP) had been implanted simultaneously in both mitral and tricuspid positions. The aim of the study was to investigate whether position-related factors played an important role in BP degeneration. There were 14 women and 1 man with a mean age of 34 +/- 11 years. The indications for the initial operation were rheumatic in 14 cases and endocarditis in one patient. The mean interval before reoperation was 7.5 +/- 3.3 years. Predominant cause of reoperation was: structural deterioration of both mitral and tricuspid BPs (6), mitral regurgitation (5), tricuspid BP dysfunction (1), para-aortic leak (1), mitro-aortic thrombi (1). Calcific deposits were the principal cause of early deterioration of mitral BPs and the major cause of late tricuspid BPs dysfunction. This lesion was predominantly related to local factors. Cuspal tears were the principal cause of late (> 9 yrs) mitral BP failure and most probably related to mechanical stress. Extensive fibrosis affected only tricuspid bioprostheses. In 7 patients more extensive degenerative changes occurred in bioprostheses in the mitral rather than the tricuspid position (Group I). However, in the remaining eight the magnitude of the changes was very similar in the two positions (Group II). The interval before reoperation was significantly longer in patients of Group II (9.8 yrs, range 5-13) than patients in Group I (4.9 yrs, range 3-6), (p < 0.01). We concluded that position-related factors exert a major role in bioprosthetic failure. These factors are more deleterious in the mitral position than in the tricuspid position.

Adolescent↗
PubMed1996

Heart transplant for the failing ischaemic ventricle.

Clinical application of heart transplantation goes beyond 28 years experience. Ischaemic heart diseases remain, with idiopathic cardiomyopathies, the main indications for cardiac transplant. A combination of haemodynamic, contractile and viability measurements may be useful to choose between transplant and coronary revascularization for the failing ischaemic ventricle. Advances in the detection of early rejection, improved organ preservation procedures, and the introduction of new immunosuppressive therapy protocols have produced dramatic results in heart transplantation. Late graft atherosclerosis remains a serious threat despite retransplantation and, in some cases, mechanical circulatory support.

Contraindications↗
PubMed1996

Plasma levels of thrombomodulin in pulmonary hypertension.

BACKGROUND: Long-standing pulmonary hypertension (PH) leads to structural alterations of the pulmonary vasculature and its endothelium, and occlusion of small vessels by microthrombi. In patients with PH, the search for factors inducing or worsening endothelium damage and in situ thrombi is still ongoing. Thrombomodulin (TM), an endothelial cell membrane protein, is a receptor for thrombin and a major anticoagulant proteoglycan. PURPOSE: To analyze plasma TM levels in patients with different forms of severe PH. PATIENTS: We prospectively studied 32 consecutive patients with PH referred for heart, lung, or heart-lung transplantation: 11 patients with primary PH (group 1), 11 patients with secondary precapillary PH (Eisenmenger's syndrome, group 2) and 10 patients with secondary postcapillary PH due to congestive heart failure (group 3). Thirty-eight healthy subjects were also studied as a control group. METHODS: Plasma concentrations of TM were measured by an immunoenzymatic technique that uses two anti-TM monoclonal antibodies that have a strong avidity and react with different epitopes of the molecule. RESULTS: Thrombomodulin plasma levels decreased in all patients with precapillary PH, and this decrease was highly significant compared with controls (26 +/- 2 versus 44 +/- 2 ng/mL, P = 0.0001). In primary PH, the TM decrease was only significant in males whereas in the Eisenmenger's syndrome TM values were the lowest of all the patients studied, with mean values twice as low as controls (22 +/- 2 versus 44 +/- 2 ng/mL, P = 0.0001). In contrast, in postcapillary PH, studied only in males, TM levels were increased (85 +/- 17 versus 54 +/- 3 ng/mL, P = 0.02). Patients with precapillary PH had more severe disease than patients with postcapillary PH, with higher pulmonary artery pressure and pulmonary vascular resistance (P < 0.001). There was no correlation between TM plasma levels and all hemodynamic variables. CONCLUSION: We found low levels of plasma TM in patients with precapillary PH but not in postcapillary PH compared with healthy controls. This may be related to the severity of PH and may contribute to the initiation or worsening of in situ thromboses frequently found in pulmonary hypertension. Further studies should analyze whether other markers of endothelial cell damage are correlated with plasma TM levels in patients with precapillary pulmonary hypertension.

Adolescent↗
PubMed1996

Cyclosporin A-mediated cholestasis in patients with chronic hepatitis after heart transplantation.

Viral chronic hepatitis often occurs in heart transplant recipients receiving cyclosporin. This essential immunosuppressive drug may induce cholestasis. We investigated the effect of treatment with cyclosporin on serum conjugated bile acids in patients with chronic hepatitis developing after heart transplantation. Fifty-nine patients were studied: 17 with chronic hepatitis, 15 heart transplant patients with normal alanine aminotransferase activity, and 27 heart transplant patients with chronic hepatitis, the last two groups receiving cyclosporin. Hepatic biochemical tests and total bile acid concentration were determined on fasting blood samples. The individual glyco- and tauroconjugated bile acids were quantified by high-performance liquid chromatography and direct spectrometry. In patients taking cyclosporin the bilirubin concentration and the alkaline phosphatase activity were increased only when hepatitis was present, in association with a slight increase in cholic acid level (5.13 microM vs. 0.68 microM; P < 0.01). Conjugated lithocholate concentration was dramatically higher when hepatitis and immunosuppression with cyclosporin were associated (1.17 microM vs. 0.03 and 0.04 microM; P < 0.01). Chenodeoxycholate was the main circulating bile acid only in the heart transplant patients treated with cyclosporin but without hepatitis. These results suggest that the mechanisms which explain the cyclosporin-associated modifications of the bile acid pool are different according to the presence or absence of hepatitis. The occurrence of hepatitis in patients on cyclosporin led to an increase in serum lithocholate and primary bile acid concentrations. Further studies are required to assess the effect of ursodeoxycholic acid for this cholestasis.

Adult↗
PubMed1996

[Video-surgery for pericardial effusion. Technique and results].

Videosurgery is a relatively non-invasive method of draining the pericardium by the creation of a pleuropericardial window. It provides an excellent view of the thoracic cavity and allows selection of pericardial and pleural, pulmonary or mediastinal biopsy sites. The authors report their preliminary results with this technique. Between May 1994 and May 1995, 22 patients with pericardial effusions were operated by videosurgery at the Pitié Hospital. None of the patients had clinical signs of tamponade. The technique consists in introducing, through 2 or 3 thoracic incisions of 15 mm, trocarts allowing passage of an endoscopic camera and different surgical instruments. Access to the thoracic cavity enabled assessment of the pleura, evacuation of pleural effusions (n = 8) and biopsy of pleural nodules (n = 2). One pulmonary biopsy was performed. Opening the pericardium enabled evacuation of pericardial effusions averaging 622 ml. Pericardial biopsies showed appearances suggesting tuberculosis (n = 2), lupic vasculitis (n = 1) and post-radiation pericarditis (n = 1). In other cases, a histologic diagnosis of non-specific pericarditis was made. A biopsy of a pleural nodule showed undifferentiated carcinoma in one case. A pulmonary biopsy revealed the presence of relatively undifferentiated carcinoma. There were no complications related to the technique. There was one recurrence of pericardial effusion at one month in a patient with carcinoma of the lung who had previously had subxiphoid drainage. There were no cases of secondary pericardial constriction. Therefore, videosurgery is a relatively non-invasive and effective technique of pericardial drainage and biopsy. When there is no emergency, it is probably the method of choice in the treatment and diagnosis of pericardial effusions.

Adult↗
PubMed1996

[Reoperation for aortic valve replacement after myocardial revascularization].

A series of 13 patients (11 male, 2 female, average age 61 +/- 6 years) with previous aortocoronary bypass surgery and reoperated for aortic valve replacement (AVR) were analysed retrospectively. At coronary bypass, 8 patients (Group I) has insignificant aortic stenosis (AS) (mean transvalvular pressure gradient < 40 mmHg and/or aortic valve surface > 1 cm2). The other 5 had no aortic valvular lesion (Group II). The average time interval between the two operations was 7 +/- 3.3 years (Group I: 6.7 +/- 3.5 years; Group II: 7.4 +/- 3.2 years). In Group I, 2 patients required early AVR (2 years) whereas the time of reoperation varied from 6 to 12 years in the other 6 patients. No operative complications related to the sternotomy or dissection of adhesions were observed. In 3 cases, it was necessary to free the implanted grafts on the right coronary artery to gain access to the initial part of the aorta. A transverse low aortotomy allowed AVR in good conditions in all cases. One patient in Group II died on the 5th postoperative day of a low output syndrome complicated by pneumonia. After an average follow-up of 3 +/- 2 years, 9 patients are still alive. Three patients in Group I died, two of cardiac failure and one of unknown causes. The authors conclude that "prophylactic" AVR in cases of insignificant AS in patients referred for coronary bypass surgery is not justified. Regular echocardiographic follow-up should lead to AVR at the most appropriate moment, sometimes after an interval of several years, with a low operative risk.

Aged↗
PubMed1996

[Long term results of the surgical treatment of obstructive hypertrophic cardiomyopathies].

Between January 1973 and December 1993, 66 patients underwent surgery in our department for hypertrophic obstructive cardiomyopathy; mean basal outflow gradient was 48.4 +/- 36 mmHg, 20 patients had mitral valve lesions. Thirty six patients underwent myotomy-myomectomy alone, 13 mitral valve replacement alone, and 17 both myotomy-myomectomy and mitral valve replacement. The 30-day mortality rate was 7.5% for all patients; predominant risk factors were gender (female), greater cardiothoracic ratio, preoperative episodes of atrial fibrillation and lack of syncope. Overall survival rate (operative mortality included) was 65.3 +/- 8.6% at 13 years. Predominant risk factors for late mortality were the same than above, plus mitral valve replacement; so mitral valve repair, whenever feasible should be undertaken. Forty nine patients are still followed up: 46 are asymptomatic; Doppler mean basal outflow gradient was reduced to 10 +/- 1.4 mmHg. In conclusion, surgery relieves symptoms and outflow obstruction, and allows mitral valve reconstruction.

Actuarial Analysis↗
PubMed1996

How to manage patients with severe left ventricular dysfunction and valvular regurgitation.

BACKGROUND AND AIMS OF THE STUDY: The purpose of this study is to analyze treatment options for valvular regurgitation with severe left ventricular dysfunction. MATERIAL AND METHODS: Results of valvular surgery in 98 patients with mitral or aortic regurgitation and severe systolic left ventricular dysfunction (LVD) were analyzed. Selection criteria were the absence of significant coronary heart disease and a resting ejection fraction (EF) < 40% for aortic and < 50% for mitral regurgitation. RESULTS: In patients with aortic regurgitation (n = 46) operative mortality was higher but not significantly so than in a control group of 238 cases (6.5% vs. 3.4%). The actuarial survival rates at five and 10 years were 84% and 55% vs. 84% and 67%, respectively. Independent preoperative predictors of severe postoperative LVD were rheumatic etiology and increased left ventricular end-systolic diameter. In patients with mitral regurgitation (n = 52), operative mortality was not significantly different from that of a control group of 273 cases (3.8% vs. 2.6%), whether the surgical procedure was valve replacement or valve repair. Perioperative morbidity was frequent (30% of cases), mainly low cardiac output, after valve replacement. The actuarial survival rates at eight years were respectively for the groups with and without LVD: 81% and 89% after valve repair, 60% and 75% after valve replacement. Independent predictors of severe postoperative LVD were increased left ventricular end-systolic volume and the type of surgery. Better results were observed after valve repair. CONCLUSIONS: It is concluded that a low EF is not a predictive factor of operative mortality but it influences late survival as do the degree of left ventricular dilatation, etiology in aortic and type of surgery in mitral regurgitation. Alternatives to valvular surgery have been envisaged but information on vasodilators in these patients is scant and results of heart transplantation are known only from a few small series.

Adult↗
PubMed1996

High prevalence of antiphospholipid antibodies in precapillary pulmonary hypertension.

OBJECTIVE: To assess prevalence and clinical associations of various antiphospholipid antibodies (aPL) in patients with primary and secondary pulmonary hypertension. METHODS: A prospective trial of aPL in 38 consecutive patients with pulmonary hypertension. Nine patients had primary pulmonary hypertension. Twenty-nine patients had pulmonary hypertension secondary to different etiologies: left heart failure, 8; congenital heart defect, 11; various lung diseases, 10. The search for aPL directed against 4 phospholipids (cardiolipin, phosphatidylserine, inositol, ethanolamine) was by ELISA. RESULTS: Eleven patients (29%) had aPL, with various phospholipid specificities. Mean pulmonary artery pressure and mean pulmonary vascular resistance of aPL positive patients were not different from those of aPL negative patients. Mean pulmonary wedge pressure was significantly lower in aPL positive patients than those without aPL. Positive aPL were detected only in patients with precapillary pulmonary hypertension (11/30; 36.6%). The prevalence of aPL in primary (4/9; 44%) was not significantly different from aPL in secondary (7/29; 24%) pulmonary hypertension. There was no association between the presence of aPL and prior thrombosis or recurrent fetal losses. CONCLUSION: The frequent positivity of aPL in precapillary pulmonary hypertension, irrespective of its cause and severity, suggests the existence of an associated endothelial disease. These antibodies might play a role in the initiation and/or progression of in situ thromboses frequently observed in precapillary pulmonary hypertension. Our results reinforce the necessity of longterm anticoagulant treatment in these patients.

Adolescent↗
PubMed1996

[Cardiac transplantation. Lack of donor organs. Current status].

The lack of donor organs in France has led to a decrease in the number of cardiac transplantations (636 in 1990. 429 in 1994), despite the fact that the number of indications remains high. The reasons for this inadequation are multiple, but family refusal remains the major cause (65% of cases of non-donation). Efforts should continue to try and reverse this attitude to make this unequaled treatment available. The difficulties should in no case influence the indications of transplantations.

Attitude to Death↗
PubMed1995

Pulmonary hypertension and dexfenfluramine.

Appetite suppressants, including aminorex and fenfluramine, have been associated with pulmonary hypertension ever since the well-known outbreak of primary pulmonary hypertension in Europe after treatment with aminorex. The usage of a new anorectic agent, dexfenfluramine, has recently increased dramatically in developed countries. We report 2 new cases of lethal pulmonary hypertension associated with the use of dexfenfluramine.

Female↗
PubMed1995

Dynamic cardiomyoplasty: effect of discontinuing latissimus dorsi muscle stimulation on left ventricular systolic and diastolic performance and exercise capacity.

OBJECTIVES: This study sought to assess the short-term effect of discontinuing latissimus dorsi muscle stimulation on left ventricular systolic and diastolic performance and exercise tolerance in patients with improved functional status by cardiomyoplasty, in whom latissimus dorsi muscle was fully conditioned. BACKGROUND: Cardiomyoplasty has consistently improved the functional status of patients, but the short-term effect of latissimus dorsi muscle contraction has not been assessed in these patients. METHODS: Right-heart catheterization, Doppler-echocardiography and maximal exercise testing with expired gas analysis were performed in 10 patients with congestive heart failure who had undergone cardiomyoplasty at least 6 months earlier. Data were obtained when the latissimus dorsi muscle was stimulated every other systole and after stimulation was discontinued for 1 h. The power of this study to detect a 10% difference was > 80%. RESULTS: After cardiomyoplasty, left ventricular ejection fraction increased from 0.22 +/- 0.08 (mean +/- SD) to 0.27 +/- 0.07 after 6 months (p < 0.02 vs. before cardiomyoplasty) and to 0.24 +/- 0.09 after 1 year; functional class went from 3.0 +/- 0.0 to 2.0 +/- 0.5 after 6 months and to 2.0 +/- 0.7 after 1 year (both p < 0.001 vs. before cardiomyoplasty). After discontinuation of latissimus dorsi muscle stimulation, cardiac index did not change (2.28 +/- 0.45 vs. 2.30 +/- 0.46 liters/min per m2). Mean systemic arterial and pulmonary capillary wedge pressures were also similar (85.2 +/- 6.0 vs. 88.4 +/- 5.6 mm Hg and 14.9 +/- 7.1 vs. 13.6 +/- 6.8 mm Hg, respectively). Doppler E/A ratio decreased from 1.04 +/- 0.33 to 0.83 +/- 0.25 (p < 0.02), suggesting that left ventricular diastolic function may have been improved by latissimus dorsi muscle stimulation. Peak oxygen consumption was unaltered (1,633 +/- 530 vs. 1,596 +/- 396 ml/min). CONCLUSIONS: Alterations in left ventricular diastolic rather than systolic function may be responsible for the long-term clinical benefits of cardiomyoplasty.

Adult↗
PubMed1995

Extra-annular procedures in the surgical management of prosthetic valve endocarditis.

Severe acute endocarditis can be associated with major destruction of the annulus. Meticulous surgical debridement of friable necrotic material is always necessary and major damage to the annulus of the valve may impair secure seating of the prosthesis. Extra-annular implantation of a prosthesis may be a life-saving procedure when annular implantation is impossible. Between 1978 and 1989, 36 patients underwent extra-annular complex procedures for annular abscesses. The infection involved the aortic prosthesis and the annulus in 22 patients, and the mitral prosthesis and the annulus in 14 patients. In cases of aortic root abscess, a subcoronary valved graft (11 patients), a supracoronary valved conduit (ten patients) or a left ventricle-abdominal aorta valved conduit (one patient) were implanted. In cases of mitral valve endocarditis with extensive annular abscess, intra-atrial insertion of a mitral prosthesis was performed. In such cases, repair of the aortic root with a valved conduit or intra-atrial implantation of a mitral valvular prosthesis can be life saving and can be expected to give excellent long-term results.

Abscess↗
PubMed1995

Lymphoproliferative disorders after organ transplantation: a report of 24 cases observed in a single center.

PURPOSE: Organ recipients are at a high risk of post-transplant lymphoproliferative disorders (PTLDs) as a complication of immunosuppressive therapy. We report the incidence, clinical presentation, pathologic findings, treatment, and outcome for 24 cases of PTLD observed at our institution. PATIENTS AND METHODS: Twenty-four (1.7%) of 1,385 organ transplant recipients developed PTLDs. Dosages of immunosuppressive drugs were reduced in 19 patients. Treatment consisted of anti-B-cell monoclonal antibodies (12 patients), and/or chemotherapy (eight patients), or surgery (two patients). RESULTS: The median time between grafting and the onset of PTLD was 210 days. Tumors were classified as monomorphic and polymorphic in nine and 15 cases, respectively. Three of 24 cases were of T-cell origin. Genotypic studies confirmed the monoclonality of the tumors in 11 cases among 14 PTLDs tested. Epstein-Barr virus (EBV) infection was associated with 70% of B-cell PTLDs tested. The overall survival duration was 5 months. Ten patients are alive and disease-free with a median follow-up time of 37 months; most were treated with anti-B-cell antibodies. Two other patients died in complete remission of unrelated causes at 33 and 38 months. CONCLUSION: Anti-B-cell monoclonal antibody therapy seems to be effective in PTLD, even in monoclonal B-cell forms, but other approaches will be necessary to improve survival further.

Adolescent↗
PubMed1995

Urate-oxidase for the treatment of tophaceous gout in heart transplant recipients. A report of three cases.

Gout in heart transplant recipients is common and poses a significant therapeutic challenge. Concomitant administration of azathioprine and allopurinol therapy carries a high risk of leukopenia. Uricosuric agents can cause renal lithiasis and/or acute renal failure in patients with renal failure and/or high urinary levels of uric acid. We report our experience with urate-oxidase in three heart transplant recipients with severe polyarticular and tophaceous gout, a history of leukopenia under allopurinol and unresponsiveness or contraindications to uricosuric agents. Urate-oxidase was given parenterally in a dosage of 1000 units per day, seven days a month. The injections were done intramuscularly in one patient and intravenously in the other two, who were under anticoagulant therapy. Patients 1 and 2 received 12 and 6 courses, respectively. The third patient had had four courses and was still under treatment at the time of this writing. Shrinking of the tophi and improved mobility of the fingers were seen in all three patients after the second course. No adverse effects were recorded. Our experience suggests that urate-oxidase therapy may decrease the urate burden in patients with severe tophaceous gout. Urate-oxidase therapy should be viewed as a phase in the treatment of gout, which must be followed by administration of another agent.

Adult↗