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 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The application of lung transplantation to the pediatric population was a natural extension of the success realized in our adult transplantation program, which began in 1982. Twenty pediatric patients (age range 3 to 18 years) have had heart-lung (n = 11), double lung (n = 8), and single lung (n = 1) transplantation procedures. The causes of end-stage lung disease were primary pulmonary hypertension (n = 7), congenital heart disease (n = 5), cystic fibrosis (n = 4), pulmonary arteriovenous malformation (n = 2), graft-versus-host disease (n = 1), and desquamative interstitial pneumonitis (n = 1). Four (20%) patients had thoracic surgical procedures before the transplantation operation. The survival was 80% at a mean follow-up of 2 years. Immunosuppressive drugs included cyclosporine (n = 9) or FK 506 (n = 11) based therapy with azathioprine and steroids. Children were followed up by means of spirometry, transbronchial biopsy, and primed lymphocyte testing of bronchoalveolar lavage fluid. The mean number of treated episodes of rejection was 1.4 at 30 days, 0.5 at 30 to 90 days, and 1.4 at more than 90 days, and the first treated rejection episode occurred on average 28 days after the operation. Obliterative bronchiolitis developed in four (25%) of 16 patients surviving more than 100 days. Results of pulmonary function tests have remained good in almost all recipients. The greatest infectious risk was that of cytomegalovirus: one death and one case of pneumonia. Posttransplantation lymphoproliferative disease was diagnosed in two (12.5%) patients; both recovered. The most common complications were hypertension (25%) and postoperative bleeding (15%). Early results indicate that lung transplantation is a most promising therapy for children with severe vascular and parenchymal lung disease.
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PMID:Pediatric lung transplantation. The years 1985 to 1992 and the clinical trial of FK 506. 767 72

A retrospective cohort study was carried out in 61 patients (30 males, 31 females, age 24.6 +/- 11.8 years) with primary pulmonary hypertension diagnosed by strict clinical and hemodynamic criteria, to obtain an understanding of the natural history and prognostic markers. While 15 patients were alive, 46 patients (76%) had expired during the follow up period. Two, five and ten years survivals were 48%, 32% and 12% respectively. Median survival duration from time of diagnosis was 22 months. The survivors had significantly higher age of onset, cardiac index and significantly lower right atrial mean pressure, right ventricular end diastolic pressure, cardiothoracic ratio from chest rontgenogram and calculated pulmonary vascular resistance as compared to non survivors. While pulmonary artery systolic pressure was not significantly different, pulmonary artery diastolic and pulmonary artery mean pressures were significantly lower in survivors than in non-survivors. Lower New York Heart Association class, right atrial mean pressure < or = 7 mm Hg, right ventricular end diastolic pressure < or = 10 mmHg, cardiac index > 2.5 L/min/m2, pulmonary arterial oxygen saturation > 60%, were associated with significantly longer survival. The degree of pulmonary arterial hypertension had an indirect prognostic effect through the above parameters. Vasodilator therapy did not significantly alter the outcome of patients with primary pulmonary hypertension.
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PMID:Primary pulmonary hypertension: natural history and prognostic factors. 782 39

Non-resolved chronic pulmonary thromboembolism is a frequent cause of pulmonary hypertension. In long-standing disease hypertension is progressive due to intimal and medial changes in the perfused vessels. Non-resolution of thromboemboli is often associated with underlying coagulopathies; the presence of a lupus anticoagulant may pose a significant problem in the peri-operative management of these patients. Pulmonary thrombendarterectomy presents an efficient option of treatment which is feasible in the majority of patients. By means of pulmonary angiography and computed tomography operability is verified by the often difficult recognition of thromboembolic changes in the central pulmonary arteries. Patients with solely peripheral thromboembolic changes or primary pulmonary hypertension must be excluded. In presence of significant exertional dyspnea and/or pulmonary pressure elevation surgery is indicated. Mortality is high and mainly related to unrelieved pulmonary hypertension or pulmonary complications; pulmonary reperfusion edema, respiratory failure or pneumonia and sepsis. In all survivors the reduction of pulmonary hypertension is highly significant and persistent. Thromboembolic pulmonary hypertension may be treated curatively in most patients by thrombendarterectomy. Correct selection of surgical candidates is mandatory, and the patients should preferably be diagnosed and undergo surgery in an early stage of their disease.
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PMID:[Surgical treatment of thromboembolism-induced pulmonary hypertension]. 786 94

We investigated the relation between home blood pressure (BP) and body weight in 38 young normotensive men (mean age, 16 years) whose parents were normotensive (PNT group) and 34 age- and sex-matched normotensive men, one or both of whose parents were hypertensive (PHT group). Although causal BP measurements were similar in both groups, home systolic BP was significantly higher in the PHT group (123 +/- 1 mm Hg) than in the PNT group (116 +/- 1 mm Hg). Body weight was significantly greater in the PHT group (66.0 +/- 1.4 v 61.8 +/- 1.3 kg, P < .05) and body mass index (BMI) was not significantly higher in the PHT group (22.4 +/- 0.5 v 21.3 +/- 0.5 kg/m2, P = .09). Body weight (r = 0.38) and BMI (r = 0.42) were significantly correlated with home systolic BP in the PHT group. There were no differences in serum lipid or uric acid concentrations between the two groups. Our results showed that young normotensive subjects with a genetic predisposition to hypertension weighed more and had higher home systolic BPs compared with subjects without a family history of hypertension. Our observations further indicated a close relationship between a family history of hypertension and increased body weight, even in young normotensive men.
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PMID:Relation of home blood pressure to body weight in young normotensive men with or without family history of hypertension. 791 46

Nitric oxide is widely distributed in the body. It has an important role in the regulation of the circulation and as yet, ill-defined roles in nervous and immune systems. It is derived from L-arginine from a reaction catalysed by a constitutive intracellular enzyme, nitric oxide synthase. It is recognised as the endogenous nitrovasodilator whose action is mimicked by all exogenous nitrovasodilators. After production in the vascular endothelial cell, it diffuses to the smooth muscle cell where it activates the enzyme guanylate cyclase which leads to an increase in cyclic GMP and thence to muscle relaxation. The duration of its action is brief, a few seconds. Disorders of NO metabolism underlie many disease states including endotoxic shock in which prolonged production of nitric oxide may be induced by cytokines. Deficiencies in endogenous production may account for hypertension in various disease states including atherosclerosis and chronic renal failure. NO therapy been used experimentally to successfully treat idiopathic pulmonary hypertension and pulmonary hypertension associated with cardiac and respiratory diseases. However, the long-term benefits have yet to be studied. Administration of NO requires the use of a device to monitor the concentrations of both NO and of NO2. The latter is a noxious agent and a time-related product of the reaction between NO and O2 and is a possible contaminant of preparations of NO. Precautions must be taken to prevent contamination of the work-place atmosphere with NO and NO2. These include gas scavenging and the use of a leak-free system for spontaneous and mechanical ventilation. Using NO in its gaseous form, clinicians have at long last been provided with the means to treat pulmonary hypertension without adversely causing systemic hypotension. The therapy is most suited to short-term use in mechanically ventilated patients. Safe practical long-term NO therapy must await the development of agents which release NO from aerosol preparations.
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PMID:The role of nitric oxide (formerly endothelium-derived relaxing factor-EDRF) in vasodilatation and vasodilator therapy. 812 32

In chronic respiratory diseases, especially chronic obstructive pulmonary disease (COPD) pulmonary arterial hypertension is generally mild to moderate and the necessity for treating it can, therefore, be questioned. In fact, pulmonary hypertension, even when modest, may worsen markedly during acute episodes, exercise and sleep. These acute increases in mean pulmonary artery pressure (PAP) could contribute to the development of right heart failure. Therefore, the medical treatment of pulmonary hypertension is justified. There are, at the present time, no selective pulmonary vasodilators, with the exception of inhaled nitric oxide. Indeed, vasodilators appear less effective in COPD compared to primary pulmonary hypertension. Thus, there is, at present, no justification for the long-term use of vasodilators in COPD patients. Long-term oxygen therapy (LTOT) attenuates and sometimes reverses the progression of pulmonary hypertension, although the condition rarely returns to normal. We do not know whether the structural changes of the pulmonary vasculature in COPD patients are potentially reversible with LTOT. The longer the daily duration of LTOT the better are the haemodynamic results. At present, LTOT remains the best treatment for pulmonary hypertension in COPD patient. In the future, treatment of this condition in COPD patients could combine LTOT and specific vasodilators.
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PMID:Medical treatment of pulmonary hypertension in chronic lung disease. 814 14

This paper reviews the effects of pulmonary artery hypertension on gas exchange by exploring three different issues, namely: 1) how does gas exchange behave in diseases characterized by increased vascular tone (primary pulmonary hypertension (PPH), chronic obstructive pulmonary disease (COPD) and interstitial pulmonary fibrosis (IPF)) or decreased vascular tone ("hepatopulmonary syndrome"); 2) how does exercise, as a non-pharmacological tool of increasing pulmonary blood flow, modify gas exchange in these diseases; and 3) how do several drugs that lower (vasodilators) or increase (almitrine) the active component of pulmonary hypertension interact with gas exchange. Available data show that: 1) in PPH a high pulmonary vascular tone enhances gas exchange and when it is lowered, either by oxygen or vasodilators, ventilation perfusion (VA/Q) distributions deteriorate; 2) in COPD a lowered (vasodilators) or augmented (almitrine) active vascular tone is almost invariably paralleled by a deterioration or enhancement of ventilation-perfusion matching, respectively; 3) in IPF an adequate active response of the pulmonary vasculature is essential to maintain gas exchange, both at rest and during exercise; and 4) in patients with liver cirrhosis a low pulmonary vascular tone induces an abnormal VA/Q distribution. In summary, these data show that any situation and/or therapeutic intervention that lowers the active vascular tone deteriorates VA/Q relationships and vice versa. The final effect of pulmonary vascular tone on arterial oxygen tension (PaO2) is less predictable. The reason for this uncertainty is that the actual PaO2 value depends on the interplay of the intra- and extrapulmonary factors that control gas exchange in humans, and not only on the degree of VA/Q mismatching.
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PMID:Effect of pulmonary hypertension on gas exchange. 828 57

Since dyspnoea on exertion is very often the first symptom of precapillary pulmonary hypertension (PPH), either from chronic thromboembolic pulmonary hypertension (CTEPH) or from idiopathic pulmonary hypertension (IPH), these patients are often first examined in a pulmonary function laboratory. We carried out a retrospective study (1987-1992) on pulmonary function in 34 patients diagnosed to have PPH by means of specific diagnostic tools, out of 5,467 patients first attending our laboratory. Nine suffered from IPH, 10 from CTEPH and 15 from Eisenmenger physiology. This last group differed from the others, since its diagnosis had been known for a long time and the stage of the disease was more advanced, when pulmonary function tests were performed in our laboratory (with a view to transplantation). Respiratory function, blood gases and arterial oxyhaemoglobin saturation (HbSaO2) during exercise (Bruce protocol), diffusing capacity of the lungs for carbon monoxide (DLCO), shunt fraction (QS%) (approximation obtained from arterial oxygen tension (PaO2) after 100% oxygen breathing) had been evaluated. In the first two groups, in contrast to other reports, we could observe no obstructive defect. Only 20% of the subjects had restrictive defects, however mild. The typical functional picture of these patients revealed normal lung volumes, normal or slightly reduced DLCO, mild hypoxaemia with hypocapnia, severe HbSaO2 drops during exercise, and pathological QS%. We conclude that every time a patient presents with breathlessness at rest or on exercise, a normal chest X-ray and respiratory function tests, pulmonary hypertension must be suspected and subject to specific and invasive tests. More severe functional impairment was observed in the PPH from the Eisenmenger disorder. This might be due to a more advanced stage of this type of hypertension at the time of our observation and/or to the different mechanisms of the diseases themselves.
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PMID:Respiratory function in precapillary pulmonary hypertension. 836 83

Pregnancy carries substantial maternal and fetal risks in patients with uncorrected or palliatively corrected cyanotic congenital heart disease (CHD). In tricuspid valve Ebstein's anomaly, pregnancy is well tolerated. Maternal mortality in tetralogy of Fallot seems to be less than 10%, but it exceeds 50% in Eisenmenger's syndrome and primary pulmonary hypertension (PPH). Maternal hematocrit greater than 60%, arterial oxygen saturation lower than 80%, right ventricular hypertension, and syncopal episodes are poor prognostic signs. Maternal risk could be reduced by vaginal delivery. Continuous monitoring of arterial and central venous pressure, electrocardiography, and pulse oximetry are recommended for every anesthetic procedure. The use of a pulmonary artery catheter is controversial and probably should be avoided in parturients with cyanotic CHD or PPH. The choice of anesthetic technique and drugs per se is of secondary importance and should be governed by individual preferences. Titration of anesthetic drugs, general anesthesia with controlled ventilation, or, preferably, regional anesthesia with spontaneous breathing should be used cautiously to avoid worsening of the preexisting condition. Prevention of excessive erythrocytosis, volume and blood loss substitution, cardiocirculatory pharmacologic support, prophylaxis of infective endocarditis, and judicious use of anticoagulant drugs should be applied as indicated by the type and presentation of CHD. Poor outcome of pregnancy in PPH requires an early consideration of heart-lung or lung transplantation. Multidisciplinary team effort and prolonged monitoring in the intensive care unit are mandatory to ensure a favorable outcome for cyanotic CHD and PPH parturients.
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PMID:Cyanotic congenital heart disease and pregnancy: natural selection, pulmonary hypertension, and anesthesia. 837 15

The normal functional state of the vasculature and the events leading to the development of significant arterial disease involve the interaction of important vasoactive substances, which play important modulating or initiating roles in the development of hypertension and arteriosclerosis. Three endothelins have now been identified, of which ET-1 is the best characterized. ET-1 is produced by epithelial, mesangial, neuronal and glial, and liver cells, and is the most potent vasoconstrictor yet found. Each endothelin is derived from a different gene on separate chromosomes, and each binds to at least 2 types of receptor. The plasma half-life of ET-1 is about 7 min, and this provides a rapid mechanism for adjusting vascular resistance or blood pressure. The actions of endothelin are mediated through several pathways of postreceptor signaling, including activation of the mitogen-activated protein kinase cascade, which give rise to its growth-stimulating properties. Secretion of ET-1 from cultured endothelial cells is stimulated by a wide range of substances, and is inhibited by some prostaglandins. Endothelin in turn stimulates secretion of nitric oxide, arginine vasopressin and atrial natriuretic peptide, and participates in the hormonal control of salt and water balance. Hypoxia and ischemia augment ET-1 secretion, as does insulin, and this could play a role in the accelerated vascular disease of diabetes. ET-1 also causes bronchoconstriction and has been implicated in the development of acute asthma, primary pulmonary hypertension and pulmonary fibrosis. Its role in hypertension is still debatable, though most of the manifestations of congestive heart failure can theoretically be explained by the actions of ET-1. Endothelin also has extensive renovascular and parenchymal effects in the kidney. It is hoped that a fuller understanding of the role of endothelins in normal or pathologic vasculature will lead to effective therapy based on antagonism or augmentation of specific functions.
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PMID:Endothelins as cardiovascular peptides. 873 84


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