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D Metras

Publications and source records attributed to D Metras.

At least 37 records · Page 2Linked to original sources
PubMed1996

Balance between alveolar macrophage IL-6 and TGF-beta in lung-transplant recipients. Marseille and Montréal Lung Transplantation Group.

Acute inflammation in the lung is characterized by a phase of tissue injury followed by a phase of tissue repair. When the latter is excessive, fibrosis occurs. Alveolar macrophages (AM) can produce cytokines involved in both phases of acute lung inflammation, notably interleukin-6 (IL-6), involved in injury and transforming growth factor-beta (TGF-beta), mediating repair. We hypothesized that AM were activated in both phases, and studied IL-6 and TGF-beta production by AM during complications of lung transplantation, acute rejection (AR), and cytomegalovirus pneumonitis (CMVP). In addition, we analyzed these cytokines in bronchiolitis obliterans (BO), a fibrotic complication of lung transplantation linked to previous AR and CMVP. At the onset of AR and CMVP, IL-6 secretion increased, whereas AM TGF-beta content was increased, but not its secretion. In contrast, with time, IL-6 reached control value whereas TGF-beta secretion rose significantly. In BO, IL-6 was not oversecreted, but TGF-beta increased, notably before functional abnormalities occurred. These results show that during acute complications of lung transplantation, AM display an early activation with oversecretion of IL-6, which is involved in tissue injury, counterbalanced by a late activation in which TGF-beta predominates, mediating tissue repair. The results provide new insights into the pathogenesis of BO, which is linked to acute complications of lung transplantation through this biphasic AM activation.

Adolescent↗
PubMed1996

Anatomic and physiologic bases for the Ross procedure.

Now that the Ross procedure (RP) has been established as the best method of aortic valve replacement (AVR) in several cohorts of patients, it is appropriate to analyze the evolution, as well as the anatomic and physiologic bases for it. Reviewing the evolution of this operation, one may understand the time lapse between its inception and the universal performance of this procedure. Experimental work began as early as 1927 by Hochrein. He was followed by the Stanford group, Lower in 1960 and 1961, and Pillsbury and Shumway in 1966. Successful clinical application by Donald Ross in 14 patients, two in the mitral and 12 in the aortic positions, was accomplished in 1967. Several important developments followed, including Marcel Geens' study of the blood supply to the ventricular septum in 1971 together with the improvement in surgical results following the initial experience of Gonzalez-Lavin and Ross. Further developments included assessment of the tensile strength of the pulmonary valve (PV) by Gorczynski (1982), ability to grow by Murata (1984), a finding of low Ca++ content of the PV by Livi in 1987 and of excellent hydraulic function by Wareesena in 1994. Finally there was universal acceptance by Elkins, Duran, and others, culminating with the Ross Registry and the establishment of the Ross Colloquium by Oury et al. A review of the anatomical features of the PV are compared with those of the aortic valve (AV), including gross anatomy and relationship to the sinotubular junction, scan microscopy and anisotropic properties of both AV and PV. The blood supply to the ventricular septum will be outlined by reviewing Marcel Geens work. The hemodynamics as reported by several investigators are reviewed. The clinical evidence of growth by Elkins et al. is outlined. Based on this increasing knowledge, indications and contraindications for AVR by the RP are discussed.

Aortic Valve↗
PubMed1996

False aneurysm: a rare and potentially severe complication after pulmonary autograft operation.

A case of a false aneurysm arising at the proximal suture of an aortic root replacement with a pulmonary autograft is presented. This complication did not occur in the first postoperative month but was discovered late, and the female eight-year-old patient was in an extremely serious condition. She was reoperated on an emergency basis but died of acute pulmonary artery hypertension. The mechanism of the occurrence of such a case is discussed. In the absence of infection, structural weakness of the right ventricular muscle with progressive tearing is suggested. Strict and prolonged echocardiographic surveillance after the Ross procedure and early reoperation are mandatory.

Aneurysm, False↗
PubMed1995

Standard orthotopic heart transplantation versus total orthotopic heart transplantation. A transesophageal echocardiography study of the incidence of left atrial thrombosis.

BACKGROUND: After standard orthotopic heart transplantation (Sd HT), the enlarged resultant atria may promote atrial thrombosis. The purpose of this study was to compare the incidence of spontaneous echo contrast and left atrial thrombosis after Sd HT and total orthotopic (Tot HT) heart transplantation. METHODS AND RESULTS: Transesophageal echocardiography (TEE) was performed in 75 patients with Sd HT and in 20 patients with Tot HT. Despite the use of antiplatelet therapy, an acute arterial embolism occurred in 11 (15%) of the 75 patients with Sd HT but in none of the 20 Tot HT patients. All patients were in sinus rhythm. Left ventricular ejection fraction was similar in Sd HT and Tot HT patients. Left atrial diameter was smaller in Tot HT patients than in Sd HT patients (41 +/- 4 versus 58 +/- 6 mm, P < .001). In Sd HT patients, spontaneous echo contrast was present in 43 patients (57%) and was associated with left atrial thrombus in 20 patients (on the left atrial appendage in 12 patients, on the posterior wall in 6, and on the suture in 2). No thrombus was detected by transthoracic echocardiography; all thrombi were detected by TEE. On the other hand, no left atrial thrombus was observed in Tot HT patients, and only 1 patient had spontaneous echo contrast. Of the 11 Sd HT patients who experienced an arterial embolism, 5 had both spontaneous echo contrast and left atrial thrombus and 5 had only spontaneous echo contrast. CONCLUSIONS: This study demonstrates a high rate of left atrial thrombus after Sd HT and emphasizes the role of TEE in the follow-up of these patients. The therapeutic implications are the need for a preventive anticoagulant therapy in the high-risk population receiving Sd HT diagnosed with TEE and the consideration of Tot HT as a better surgical approach as far as thrombotic complications are concerned.

Adult↗
PubMed1995

Orthotopic heart transplantation with preservation of the left heart.

In December 1992, cardiac transplantation (for right heart failure with partially occluded pulmonary arteries but with a normal left ventricle) was accomplished with partial resection of right atrium and ventricle but with preservation of the left heart, obtaining a three-ventricle heart. The short-term result (27 months) is good, with normal native and grafted heart rhythms and functions, allowing us to conceive of the possible application of this procedure in some other selected cases.

Adult↗
PubMed1995

Bilateral single-lung transplantation in children.

BACKGROUND: This study examined our experience with bilateral single-lung transplantation in pediatric patients. METHODS: Between 1988 and 1995, we have performed 32 double-lung transplantations in children. The first 10 were performed en bloc, the following 22 by bilateral single-lung transplantation. Indications for bilateral single-lung transplantation were cystic fibrosis in 16 patients, primitive obliterative bronchiolitis in 1, pulmonary artery hypertension in 1, and retransplantation in 4. Patients' ages ranged from 7 to 16 years (mean, 12 years). Four patients underwent a parenchymal reduction (lobectomy or bilobectomy). Bilateral single-lung transplantation was performed with a "clam-shell" incision, normothermic cardiopulmonary bypass, and a beating heart. RESULTS: There was one postoperative death (heart failure in a retransplantation patient). Bleeding was moderate, and 4 patients had a bloodless procedure. Bronchial healing was satisfactory, with 3 patients receiving temporary left main bronchus stenting. There were two hospital deaths (recurrent cytomegalovirus infection in a retransplantation patient and multiorgan failure at 2 months) and seven late deaths, caused by infection (mostly cytomegalovirus), obliterative bronchiolitis, or both. Actuarial survival was 75% at 1 year, 56% at 2 years, and 36% at 3 years. CONCLUSIONS: We conclude that bilateral single-lung transplantation appears to be an acceptable technique, even in small children. Bronchial healing is satisfactory, and no revascularization procedure appears necessary. Midterm and long-term results are comparable with those of heart-lung transplants, and in view of the current problems with organ donation, we think it is an adequate strategy in pediatric lung parenchymal disease.

Adolescent↗
PubMed1995

Experimental basis for autograft growth and viability.

An experimental model has been designed to evaluate the potential of growth of aortic vascular autografts and homografts. In 25 young rabbits a graft interposition was performed at the level of the infrarenal aorta, with micro-surgical techniques. Different groups included fresh autografts, fresh and cryopreserved homografts and controls. Animals were allowed to grow normally and were sacrificed when adult, at the mean weight of 2.99 kg. We studied for each case the growth of the native aorta and that of the graft, and calculated the growth-ratio (growth of the graft/growth of native vessel). Grafts and adjacent aorta were histologically studied. The growth in terms of increase in diameter of the native aorta was identical between the four groups (from 1.97 +/- 0.14 mm to 2.86 +/- 0.23 mm). Growth of the graft was normal (mean growth ratio 1.08 +/- 0.21) for autografts. Growth was absent (mean ratio 0.12 +/- 0.15) for fresh and cryopreserved homografts (p = 0.001). Histologic study showed normal optical microscopic aspects (endothelial layer, intima and media thickness and cellularity) when growth had been normal and, when growth had been absent, aspects compatible with rejection including mainly intima hyperplasia and media attenuation. In conclusion, normal growth of the arterial autografts was confirmed, the histologic features of these grafts were normal, but homologous aortic grafts, fresh or cryopreserved, never showed any growth potential.

Aging↗
PubMed1995

[Lung transplantation and respiratory function tests. Functional outcome in the presence and absence of chronic rejection].

Between may 1988 and march 1993, twenty five double lung transplants were performed and five heart/lung transplants. Lung function tests (EFR) were performed on these patients for a period of 19.2 +/- 3.4 months. The aim of this study was two-fold. First, to report our overall results and to estimate the role of the single breath nitrogen washout test (N2 slope) in the early detection of chronic rejection (RC). Secondly, to assess the diagnostic value of EFR in the discrimination of acute rejection (RA) and of cytomegalovirus pneumonitis (PCMV). There were 41 episodes of RA and 21 episodes of PCMV and they were analysed as a function of the presence or absence of RC. In the absence of RC, RA produced no change in EFR and PCMV was accompanied by a pure restrictive ventilatory defect. On the otherhand, RA and PCMV lead to a worsening of obstruction and an hypoxaemia which characterises RC. The diagnosis of RC was made, on average, 14.4 +/- 2.9 months after surgery. However, from the sixth month the nitrogen slope was significantly increased and other parameters of EFR (particular maximal flows at low lung volume) remained normal. Thus, our results suggest that the N2 slope, measured in the absence of any evidence of acute rejection, constitutes an early test for chronic rejection. When its pathological rise is compared to the results of histology (presence or absence of RC), it shows a sensitivity of 0.94 and a specificity of 0.93.

Acute Disease↗
PubMed1994

Clinical and molecular study of DiGeorge sequence.

DiGeorge sequence (DGS) is a developmental field defect of the third and fourth pharyngeal pouches. The cardinal features of the syndrome are hypo- or aplasia of the thymus and parathyroids, congenital heart defect of the conotruncal type and characteristic facial dysmorphism. Such a pattern of malformations has been associated with various conditions but it is now well established that most cases of DGS are due to haplo-insufficiency of the chromosome 22q11 region. We report here a series of 16 patients, including a familial case. Minimal criteria for inclusion in this series were two or more of the following features: conotruncal heart defect, hypocalcaemia, hypoplastic/absent thymus and typical facial dysmorphism. Molecular analysis with specific probes of the 22q11 region was conducted in all patients according to two methods, fluorescent in situ hybridization and DNA dosage analysis. A deletion was found at the molecular level in all patients. We emphasize the fact that clinical analysis remains an important step of the diagnosis. The implication of these molecular techniques on diagnosis, prognosis and genetic counselling of DGS are discussed.

Child, Preschool↗
PubMed1994

Thallium perfusion and myocardial hypertrophy in transplanted heart recipients with normal or near-normal coronary arteriograms.

In patients with hypertrophic cardiomyopathy or systemic hypertension, exercise thallium perfusion defects have been observed but without significant angiographic stenoses. Hypertension and myocardial hypertrophy are common in transplanted heart recipients, and the aim of this study was to determine if exercise thallium scintigraphy false-positives are frequent in transplanted heart recipients. Thirty-four transplanted heart recipients were evaluated by exercise thallium single emission computed tomography and subsequently had a normal or near normal coronary arteriogram. At the time of the exercise, the patients (28 men and six women) had a mean age of 48.9 +/- 12 years and 29 had been previously treated for systemic hypertension. The mean duration between transplantation and the exercise test was 31.6 +/- 13 months. In all patients left ventricular mass was obtained by echocardiography within 3 months of thallium 201 SPECT and was > or = 130 g.m-2 in nine males and > or = 110 g.m-2 in four females. M-mode septal + posterior end-diastolic thickness was > 23 mm in 14 patients, all of whom had been previously treated for systemic hypertension. These patients were older and endured a longer period during which the heart was kept cold but ischaemic before being grafted ('cold ischaemia') but a shorter exercise duration than patients without left ventricular hypertrophy. During exercise testing, 26 of 34 patients achieved at least 80% of their maximal predicted heart rate and two developed significant ECG changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Hyperhomocysteinaemia in heart transplant recipients.

The aim of this study was to determine the prevalence of hyperhomocysteinaemia in cardiac transplant recipients. Three groups of subjects were studied: 27 heart transplant recipients, 14 to 63 months (mean = 36.5) after transplantation; 10 patients with moderate chronic renal insufficiency without clinical evidence of vascular disease; 17 apparently healthy individuals. Twenty-five out of 27 transplanted patients had a coronaroangiography within 6 months of homocysteine measurement. Plasma homocysteine was measured both while the subject was fasting (t0) and 6 h after administration of 0.1 g.kg-1 of methionine (t6). Hyperhomocysteinaemia was present in 14/27 fasting transplanted patients and after methionine loading. Mean plasma levels of homocysteine at t0 were higher (P = 0.03) in transplanted heart recipients (15.4 +/- 7 mumol.l-1) than in the renal patients (9.9 +/- 5 mumol.l-1) despite similar mean plasma creatinin. In eight transplanted patients with angiographic coronary abnormalities of the cardiac graft, homocysteinaemia was at t0 17.1 +/- 9 mumol.l-1 and at t6 47.8 +/- 25 mumol.l-1. In 17 transplanted patients with angiographically normal coronary arteries, plasma homocysteine levels were at t0, 13.2 +/- 4 mumol.l-1 and at t6, 46.8 +/- 25 mumol.l-1. We conclude that hyperhomocysteinaemia is common in transplanted heart recipients, and partly related to renal insufficiency. No correlation was found between hyperhomocysteinaemia and angiographic evidence of coronary atherosclerosis of the graft, but the population of the study was possibly too small to establish this correlation.

Aged↗
PubMed1993

[Lung transplantation. Contraindications and new indications].

The authors review the recent changes observed in the indications for lung transplantation. Several classical contra-indications have been alleviated or even cancelled. Chronic infection presenting as cystic fibrosis has become one of the first indications for lung replacement. Respirator-dependent patients are at an operative risk comparable to the overall results. Long-term corticosteroid therapy and pleural adhesions are no longer formal contraindications but should be approached with extreme caution. In recent years, single lung transplantation has been extended to diseases, such as emphysema and pulmonary hypertension, which were formerly indications for double-lung or heart-lung transplantation. The reasons for this include donor shortage and the better 1-year survival following single lung transplantation. The most recent development is paediatric lung transplantation. The legitimacy of redo transplantation is controversial.

Adolescent↗
PubMed1993

Double-lung transplantation in mechanically ventilated patients with cystic fibrosis.

Many lung transplant programs consider ventilator dependence as a contraindication for transplantation. Among 54 patients in whom bilateral lung transplantations for cystic fibrosis were performed by the Joint Marseille-Montreal Lung Transplant Program, 10 were ventilator dependent. Three of them died in the early postoperative period (30%): 2 as a result of cerebral anoxia and sepsis, 1 of Pseudomonas cepacia pneumonia. Two patients died at 15 and 19 months after transplantation of obliterative bronchiolitis and secondary bacterial pneumonitis. Another 2 patients in whom obliterative bronchiolitis developed underwent retransplantation with a heart-lung block; 1 of those was operated on at 12 months and is well at 29 months after his initial transplantation; the second was operated on at 34 months and died of primary graft failure. Three other patients are alive and well at 3, 11, and 14 months after transplantation. Actuarial survival at 1 year was 70%. The postoperative course and the infectious and rejection complications were no different from those in patients who underwent transplantation while spontaneously breathing. Obliterative bronchiolitis developed in 66% of patients at risk (2 of 6 patients surviving more than 6 months). We conclude that transplantation in mechanically ventilated patients with cystic fibrosis is not associated with an increase in morbidity or mortality after bilateral lung transplantation. Long-term survival, as in patients who undergo transplantation while spontaneously breathing, is limited by the development of obliterative bronchiolitis.

Adolescent↗