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Biomedical subjects

P Nataf

Publications and source records attributed to P Nataf.

At least 55 records · Page 3Linked to original sources
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

Morphometric and metabolic profile of the distal segment of the internal mammary artery: caution on its use for coronary anastomoses.

OBJECTIVE: Elastic arteries were found to be less prone to intimal hyperplasia than muscular arteries. The internal mammary artery (IMA), which is elastic in its proximal segment, presents a gradual decrease of media elastic fibers along its downstream course. Metabolic and morphometric studies of the distal end of the IMA with regard to its local susceptibility to develop intimal changes were undertaken in order to evaluate the reliability of its use as an anastomotic site for bypass grafting. METHODS: Twenty distal segments of IMA were harvested from patients who had undergone myocardial revascularization. Histologic, enzyme-histochemical and morphometric studies were undertaken on these arterial segments. RESULTS: Histologic examinations indicated an elastomuscular structure in 13 patients, a muscular structure in 6 and an elastic structure in 1. Of the 20 IMAs, none was found to have intimal thickening of greater than 25% of the diameter of the lumen. The enzyme-histochemical profile of the proliferating cells found in the intimal thickening differed from normal contractile smooth muscle medial cells in the loss of myosin and mitochondrial ATPase, plasma membrane 5' nucleotidase, moderately decreased aerobic dehydrogenase and increased lactate dehydrogenase activity and ribonucleoprotein-linked pyroninophilia. Lysosomal beta-glucuronidase and sulfatase were strongly active. This enzyme behavior is unfavorable to contractile function and favorable to cell proliferation and lipid accumulation, two events strongly involved in the atherogenic process. CONCLUSION: Intimal proliferative changes were observed in the distal segment of the IMA. Although there was no histologic evidence of atherosclerotic plaque, the enzyme-histochemical profile of this intimal thickening was favorable to cell proliferation and lipid accumulation. These findings suggest that it may be beneficial to avoid coronary anastomoses with the distal end of the IMA and to use a more proximal/elastic segment.

5'-Nucleotidase↗
PubMed1996

Mitral insufficiency caused by systemic lupus erythematosus requiring valve replacement: three case reports and a review of the literature.

The increase of mitral valve insufficiency associated with systemic lupus erythematosus (SLE) seems to be related to the treatment with corticosteroids. Corticosteroids heal Libman-Sacks endocarditis, but thereby they lead to fibrotic, retracted leaflet tissue and thus to severe valvular dysfunction. We present three patients with SLE who underwent mitral valve replacement due to severe mitral insufficiency. All had been treated with corticosteroids for several years prior to the surgical intervention. Macroscopic and microscopic examination of the valves revealed no active endocarditis. Instead, fibrotic, retracted, and calcified valve leaflets could be observed in two cases, and ballooned and fibrotic leaflets in the third case. We compare our patients to 25 cases with SLE reported in the literature so far, who also had to be submitted to mitral valve replacement. Postoperative outcome was uneventful in most cases and allows surgical intervention to be considered as a feasible treatment without major risk in patients with compensated organ function.

Adolescent↗
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

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

Effect of cold anoxia and cryopreservation on metabolic and contractile functions of human mammary artery.

The ability of human internal mammary artery smooth muscle cells to maintain histoenzymatic activity and contractile response after various times of cold anoxia prior to and following cryostorage was evaluated. The results showed that the enzyme histochemical status of human mammary arteries was largely unchanged after both cold anoxia and cryopreservation. Neither in fresh nor in cryopreserved mammary arteries did cold anoxia for up to 24 h change maximal contractile responses to potassium depolarization and norepinephrine. However, compared to unfrozen controls, the contractile responses were significantly reduced in cryopreserved mammary arteries. In conclusion, after cryopreservation of human mammary arteries, the enzyme activities were globally maintained, whereas the contractile responses were reduced. For up to 24 h after harvesting cold anoxia at 4 degrees C is well tolerated and allows preservation of metabolic and functional properties of these arteries.

Cell Hypoxia↗
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

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

Clinical experience with a total artificial heart as a bridge for transplantation: the pitie experience.

Since April 1986, 82 patients have received a pneumatic total artificial heart, 62 a JARVIK-7, and 20 a Cardiowest. The duration of support ranged from less than 1 day to 603 days (mean duration: 27 +/- 82). The indications were for acute shock (38 cases) or for chronic deterioration on the transplant waiting list (44 cases). The etiology was mainly due to idiopathic and ischemic cardiomyopathy. With the help of our scoring system, we divided our patients in three groups: Chronic Implantation, represented by two females staying on device for 6 and 19 months, respectively; a High-Risk group of 29 patients characterized by high-risk indications; graft failure, rejection, postcardiotomy patient, postpartum cardiomyopathy, and valvular and congenital reoperation. In addition, the dilated and ischemic cardiomyopathy patients with a score over 6 were included in this group; and an Elective Indication group (51 patients) represented all of the dilated and ischemic cardiomyopathy patients with a score under 6. Due to the shortage of donors, our criteria for transplantation are very strict. Transplants should be made only in cases of hemodynamic stability, on an extubated patient with normal renal and liver functions, without coagulation problems or infection. With such criteria, in the high-risk group, only four patients could be transplanted and of these two are still alive. In contrast, in the elective group, 31 were transplanted (61%), and 71% of these patients were discharged. The rate is improved in the most recent cases, with 90% of the Cardiowest patients being survivors.

Acute Disease↗
PubMed1995

[Septicemia and endocarditis related to transvenous pacing leads of pacemakers: surgical indications and results].

Endocarditis of transvenous pacing leads is a rare condition. The authors review a series of 15 patients who developed bacteriologically proven septicaemia and/or endocarditis related to transvenous pacing leads, operated between 1988 and 1993. The interval between the last manipulation of the pacemaker and the onset of endocarditis was about 6 months. Six patients had had haematoma and/or infection of the pacemaker site. Endocarditis presented with chronic pyrexia (14 cases) associated with septicaemia (6 cases) and chronic local suppuration (1 case). The interval between the beginning of the pyrexia and the diagnosis was 3.4 months. Echocardiography showed a mass attached to the pacing lead in 8 cases and tricuspid valve vegetations in 4 cases. Blood cultures were positive in 13 patients and local wound swabs identified the organism in 1 patient. The commonest causal agent was the staphylococcus (epidermis in 7 cases, aureus in 4 cases). Appropriate antibiotic therapy was only effective in 1 case. The surgical indication in 13 cases was persistence of infection associated with pulmonary embolism (3) or tricuspid regurgitation (2). Complete ablation of the prosthetic material was performed by a peripheral vascular approach (2 cases), by a right atrial approach (1 case) and under cardiopulmonary bypass in 12 cases. The peroperative findings were of tricuspid valve vegetations (4 cases), thrombi on the pacing lead (7 cases) or in the right heart chambers (2 cases) or pulmonary artery (2 cases). The associated procedures performed under cardiopulmonary bypass were tricuspid valve repair (2 cases) and pulmonary thrombectomy (2 cases). Temporary and permanent epicardial leads were implanted in 10 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Cryopreserved small-diameter arterial allografts for arterial by-pass procedures: an experimental study.

The search of small-caliber vascular prosthesis for myocardial revascularization and arterial reconstruction has led to an investigation of cryopreserved arterial allografts in a sheep model. Carotid arteries with an internal diameter of 4 mm and length of 10 cm were harvested from donor sheep and soaked immediately in a cold saline solution. Nine arteries were cryopreserved in a nutrient media containing 10% DMSO as cryoprotectant and then were stored in a liquid nitrogen vapor at -150 degrees C to -170 degrees C. In recipient sheep from different species, arterial substitution of a 10 cm segment of carotid artery was realised by implantation of fresh (n = 9) or cryopreserved (n = 9) carotid artery allografts. After 3 months, the allografts were harvested. In both groups: 7/9 were patent at the time of explantation. Components of arterial allograft rejection were observed in most fresh and cryopreserved arteries: intimal thickening with cell proliferation was seen in fresh (3/7) and cryopreserved (4/8) arteries; Loss of smooth muscle medial cells was constant; Adventitia was involved by a marked inflammatory reaction. A non cellular fibrous intimal thickening and presence of large medial calcifications were essentially observed in cryopreserved arteries. In conclusion, these results show that at three months post implantation, there is little difference in the outcome of fresh and cryopreserved arterial allografts. Cryopreservation does not reduce the apparent antigenicity of small diameter arterial allografts.

Animals↗