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Biomedical subjects

M Humbert

Publications and source records attributed to M Humbert.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Treatment of pulmonary arterial hypertension].

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, in situ thrombosis, and vascular remodeling of small pulmonary arteries. It induces a fixed pulmonary arterial obstruction, persistent elevation of pulmonary arterial resistance, and eventually right heart failure. Conventional therapy is based on simple measures (exercise limitation) and nonspecific treatments (warfarin, diuretics, and oxygen). Pure vasodilators, such as calcium channel blockers, are effective only in a minority of patients who have an acute response to vasodilator testing. Intravenous prostacyclin (epoprostenol) and endothelin receptor blockers have vasodilator and antiproliferative properties. Epoprostenol therapy has significantly improved PAH prognosis and remains the first-line treatment for patients with the most severe disease. Bosentan is an interesting first-line treatment for NYHA functional class III patients. Availability of novel specific drugs (endothelin receptor type A antagonists, prostacyclin analogues, type 5 phosphodiesterase inhibitors) is opening new perspectives in PAH treatment. The long-term benefit of these drugs remains to be evaluated and their respective place in treatment of these patients is still uncertain. The evolution of therapy from vasodilators to antiproliferative agents reflects the advancement in our understanding of the mechanisms mediating pulmonary arterial hypertension.

Algorithms↗
PubMed2005

[Treatment for pulmonary arterial hypertension under the new French hospital financing system. Recommendations of the Pulmonary Vascular Diseases Working Group of the French Society of Pulmonary Medicine].

Activity-based financing (that is, casemix-based hospital payments, known as T2A) is intended to harmonize and improve the fairness of remuneration of public and private hospitals. T2A will ultimately rely mainly on a flat rate per admission, set according to the diagnosis-related group (DRG). Although payment for drugs is usually included in the DRG price, some expensive drugs will be reimbursed on an additional cost basis after implementation of a "best practices" agreement. Four drugs used for treatment of pulmonary arterial hypertension are eligible for this additional reimbursement: 3 prostacyclin derivatives (intravenous epoprostenol, inhaled iloprost, and subcutaneous treprostinil), and oral bosentan, an endothelin receptor antagonist. The Pulmonary Vascular Diseases working group of the French Society of Pulmonary Medicine has developed guidelines for the best practices in use of these drugs.

Antihypertensive Agents↗
PubMed2005

[Surgical treatment of chronic thromboembolic pulmonary hypertension].

Chronic thromboembolic pulmonary hypertension is a condition that has long remained in the shadows, a kind of orphan disease, because of the lack of any curative treatment. The renewal of interest by pulmonary specialists, cardiologists and thoracic surgeon is due to the development over the past 20 years of major new treatments: lung transplantation, continuous prostacyclin infusion, and pulmonary endarterectomy, in chronological order. Most patients with postembolic pulmonary arterial hypertension (PEPAH) in a sufficiently proximal location can benefit from curative surgical treatment by bilateral endarterectomy of the pulmonary arteries. This complex surgery, performed under deep hypothermic circulatory arrest, clears out the pulmonary vascular bed down through its subsegmental branches and results in a frank reduction in pulmonary vascular resistance and normalization of cardiopulmonary function. It is a curative procedure with a perioperative mortality rate less than 7% and a definitive result, unlike pulmonary and cardiopulmonary transplantation, which have a postoperative mortality rate of 20% and a 5-year survival rate of 50%. It is difficult to recognize the postembolic nature of pulmonary hypertension because there is no known history of venous thrombosis or embolic phenomena in more than 50% of cases. Diagnosis is based on the presence of mismatched segmental defects in the radioisotopic ventilation-perfusion scanning. To be accessible to endarterectomy, lesions must involve the main, lobar, or segmental arteries. When conducted by experienced operators according to specific protocols, pulmonary (frontal and lateral views of each lung) and multislice CT angiography optimize assessment of the lesion site. When the pulmonary vascular resistance evaluated by catheterization is correlated with the anatomical obstruction visible on the images, pulmonary endarterectomy has a mortality rate below 4% and offers the patient a substantial chance to regain normal cardiorespiratory function. In cases of pulmonary arterial hypertension due to older embolisms, major arteriolitis occurs in the nonobstructed areas and aggravates the pulmonary hypertension, which may become suprasystemic. The endarterectomy mortality rate is then higher, and in specific cases justifies preoperative medical treatment. Pulmonary or cardiopulmonary transplantation is indicated in this disease only when the lesions are too distal and thus inaccessible to endarterectomy.

Cardiac Catheterization↗
PubMed2005

Pulmonary hypertension associated with sarcoidosis: mechanisms, haemodynamics and prognosis.

BACKGROUND: Pulmonary hypertension (PH) is a rare complication of sarcoidosis, although it is not uncommon in advanced disease. METHODS: A retrospective series of 22 sarcoidosis patients (16 men) of mean (SD) age 46 (13) years with PH was divided into two groups depending on the absence (stage 0: n = 2, stage II: n = 4, stage III: n = 1) or presence (n = 15) of radiographic pulmonary fibrosis at the time of PH diagnosis. RESULTS: In both groups PH was moderate to severe and there was no response to acute vasodilator challenge. In non-fibrotic cases no other cause of PH was found, suggesting a specific sarcoidosis vasculopathy, although no histological specimens were available. In cases with fibrosis there was no correlation between haemodynamics and lung volumes or arterial oxygen tensions, suggesting other mechanisms for PH in addition to pulmonary destruction and hypoxaemia. These included extrinsic arterial compression by lymphadenopathies in three cases and histologically proven pulmonary veno-occlusive disease in the five patients who underwent lung transplantation. Ten patients received high doses of oral prednisone for PH (stage 0: n = 1, stage II: n = 4 and stage IV: n = 5); three patients without pulmonary fibrosis experienced a sustained haemodynamic response. Survival of the overall population was poor (59% at 5 years). Mortality was associated with NYHA functional class IV but not with haemodynamic parameters or with lung function. CONCLUSION: Two very different phenotypes of sarcoidosis combined with PH are observed depending on the presence or absence of pulmonary fibrosis. PH is a severe complication of sarcoidosis.

Adrenal Cortex Hormones↗
PubMed2005

Splenectomy and chronic thromboembolic pulmonary hypertension.

BACKGROUND: An increased prevalence of splenectomy has been reported in patients with idiopathic pulmonary arterial hypertension. Examination of small pulmonary arteries from these subjects has revealed multiple thrombotic lesions, suggesting that thrombosis may contribute to this condition. Based on these findings, we hypothesised that splenectomy could be a risk factor for chronic thromboembolic pulmonary hypertension (CTEPH), a condition defined by the absence of thrombus resolution after acute pulmonary embolism that causes sustained obstruction of the pulmonary arteries and subsequent pulmonary hypertension. METHODS: The medical history, clinical characteristics, thrombotic risk factors and haemodynamics of 257 patients referred for CTEPH between 1989 and 1999 were reviewed. In a case-control study the prevalence of splenectomy in patients with CTEPH was compared with that of patients evaluated during the same period for idiopathic pulmonary hypertension (n=276) or for lung transplantation in other chronic pulmonary conditions (n=180). RESULTS: In patients with CTEPH, 8.6% (95% CI 5.2 to 12.0) had a history of splenectomy compared with 2.5% (95% CI 0.7 to 4.4) and 0.56% (95% CI 0 to 1.6) in cases of idiopathic pulmonary arterial hypertension and other chronic pulmonary conditions, respectively (p<0.01). CONCLUSION: Splenectomy may be a risk factor for chronic thromboembolic pulmonary hypertension.

Case-Control Studies↗
PubMed2005

Survival in patients with class III idiopathic pulmonary arterial hypertension treated with first line oral bosentan compared with an historical cohort of patients started on intravenous epoprostenol.

BACKGROUND: The oral dual endothelin receptor antagonist bosentan improves exercise capacity and delays clinical worsening in patients with pulmonary arterial hypertension, but its use could delay starting intravenous epoprostenol, a life saving treatment. METHODS: Survival in patients with functional class III idiopathic pulmonary arterial hypertension (PAH) treated with bosentan in clinical trials was compared with historical data from similar patients treated with epoprostenol in the clinic. Statistical methods were used to adjust for possible underlying differences between the two groups. RESULTS: Baseline factors for the 139 patients treated with bosentan and the 346 treated with epoprostenol suggested that the epoprostenol cohort had more severe disease-that is, a lower cardiac index (2.01 v 2.39 l/min/m2) and higher pressures and resistance. Kaplan-Meier survival estimates after 1 and 2 years were 97% and 91%, respectively, in the bosentan cohort and 91% and 84% in the epoprostenol cohort. Cox regression analyses adjusting for differences in baseline factors showed a greater probability of death in the epoprostenol cohort (hazard ratio 2.2 (95% confidence interval 1.2 to 4.0) in the model adjusted for haemodynamics). Alternative regression analyses and analyses to adjust for different data collection dates gave consistently similar results. When matched cohorts of 83 patients each were selected, survival estimates were similar. In the bosentan cohort 87% and 75% of patients followed for 1 and 2 years, respectively, remained on monotherapy. CONCLUSIONS: No evidence was found to suggest that initial treatment with oral bosentan, followed by or with the addition of other treatment if needed, adversely affected the long term outcome compared with initial intravenous epoprostenol in patients with class III idiopathic PAH.

Administration, Oral↗
PubMed2005

[Pulmonary arterial hypertension].

INTRODUCTION: Pulmonary arterial hypertension (PAH) is a rare condition characterised by progressively elevated pulmonary arterial resistance leading to right heart failure. STATE OF THE ART: A recent classification distinguishes idiopathic PAH, familial PAH and PAH secondary to other conditions (connective tissue disease, congenital heart disease, portal hypertension, human immunodeficiency virus infection or appetite suppressant exposure). Echocardiography is the initial investigation of choice for non-invasive detection of PAH but measurement of pulmonary pressures and cardiac output during right-heart catheterization are necessary to confirm the diagnosis of PAH. Conventional treatment includes non-specific drugs (warfarin, diuretics, oxygen). Intravenous epoprostenol is the first-line treatment for the most severely affected patients. In less severe cases, the first-line treatment may include bosentan or a prostacyclin analogue. PERSPECTIVES AND CONCLUSIONS: Recent advances in the management of PAH have markedly improved prognosis. The avai-lability of novel specific drugs including type 5 phosphodiesterase inhibitors offers novel therapeutic perspectives but their exact role in the treatment of PAH is still uncertain. The evolution of therapy from vasodilators to antiproliferative agents reflects the advancement in our understanding of the mechanisms mediating pulmonary arterial hypertension.

Antihypertensive Agents↗
PubMed2005

[Genetics of pulmonary arterial hypertension: recent data and practical applications].

INTRODUCTION: Pulmonary arterial hypertension (PAHT) is defined as an increase of mean pulmonary artery pressure above 25 mmHg at rest, or 30 mmHg on exercise, due to obliteration of small calibre pulmonary arteries by proliferation of endothelial cells and smooth muscle. Beside idiopathic PAHT and that associated with other conditions, a familial form has been identified. STATE OF THE ART: Family studies have shown an association between mutations of the BMPR2 gene and PAHT phenotypes. The products of this gene appear to be involved in vascular homeostasis and its mutations are the basis of a loss this function and, in consequence, proliferation of pulmonary vascular cells. PERSPECTIVES: Certain characteristics, such as incomplete penetrance and genetic anticipation, lead to a complex relationship between genotype and phenotype and make genetic counselling difficult. Other members of the extended family of TGF-beta receptors are implicated in the development of the Osler-Rendu syndrome, but may also be associated with the development of PAHT. CONCLUSION: Progress in genetics allows better understanding of the pathophysiology of this disease and could lead to new therapeutic possibilities.

Bone Morphogenetic Protein Receptors, Type II↗
PubMed2005

[Anti IgE antibodies for the treatment of difficult asthma].

INTRODUCTION: Immunoglobulin E (IgE) is a key factor of allergic reaction and is known to be involved in the immunopathology of asthma. In this review, we discuss the results of trials of a monoclonal antibody (omalizumab) against IgE in patients with allergic asthma. STATE OF THE ART: Omalizumab is a humanised murine IgG1 kappa monoclonal antibody which is administered subcutaneously every 2 to 4weeks at a dose calculated according to the patient's body weight and total plasma IgE concentrations. It binds free circulating IgE thus preventing it from binding to high affinity receptors. Omalizumab therapy significantly reduces asthma exacerbations, improves quality of life and has a steroid-sparing effect. It has a good safety profile. This treatment appears to be more effective in the patients with the most severe disease and the worst lung function. CONCLUSION AND PERSPECTIVES: Omalizumab therapy is an important novel treatment for difficult-to-control allergic asthma. Because of its systemic mechanism of action, it may be of particular use in patients displaying multiple allergic pathologies. It remains unknown whether the beneficial effects of omalizumab could be extended to patients with severe non allergic (so-called "intrinsic") asthma, a variant of the disease which is often difficult to control.

Administration, Oral↗
PubMed2005

Benefits of omalizumab as add-on therapy in patients with severe persistent asthma who are inadequately controlled despite best available therapy (GINA 2002 step 4 treatment): INNOVATE.

BACKGROUND: Patients with severe persistent asthma who are inadequately controlled despite Global Initiative for Asthma (GINA) 2002 step 4 therapy are a challenging population with significant unmet medical need. We determined the effect of omalizumab on clinically significant asthma exacerbations (requiring systemic corticosteroids) in the first omalizumab study to exclusively enrol patients from this difficult-to-treat patient population. METHODS: Following a run-in phase, patients (12-75 years) inadequately controlled despite therapy with high-dose inhaled corticosteroids (ICS) and long-acting beta(2)-agonists (LABA) with reduced lung function and a recent history of clinically significant exacerbations were randomized to receive omalizumab or placebo for 28 weeks in a double-blind, parallel-group, multicentre study. RESULTS: A total of 419 patients were included in the efficacy analyses. The clinically significant asthma exacerbation rate (primary efficacy variable), adjusted for an observed relevant imbalance in history of clinically significant asthma exacerbations, was 0.68 with omalizumab and 0.91 with placebo (26% reduction) during the 28-week treatment phase (P = 0.042). Without adjustment, a similar magnitude of effect was seen (19% reduction), but this did not reach statistical significance. Omalizumab significantly reduced severe asthma exacerbation rate (0.24 vs 0.48, P = 0.002) and emergency visit rate (0.24 vs 0.43, P = 0.038). Omalizumab significantly improved asthma-related quality of life, morning peak expiratory flow and asthma symptom scores. The incidence of adverse events was similar between treatment groups. CONCLUSIONS: In patients with inadequately controlled severe persistent asthma, despite high-dose ICS and LABA therapy, and often additional therapy, omalizumab significantly reduced the rate of clinically significant asthma exacerbations, severe exacerbations and emergency visits. Omalizumab is effective and should be considered as add-on therapy for patients with inadequately controlled severe persistent asthma who have a significant unmet need despite best available therapy.

Administration, Inhalation↗
PubMed2005

Anti-endothelial cell antibodies in idiopathic and systemic sclerosis associated pulmonary arterial hypertension.

BACKGROUND: It has previously been shown that IgG antibodies from patients with limited cutaneous systemic sclerosis (SSc) bind to specific microvascular endothelial cell antigens. Since patients with limited cutaneous SSc are prone to develop pulmonary arterial hypertension (PAH), and since endothelial cell activation is involved in the pathogenesis of idiopathic PAH (IPAH), a study was undertaken to examine the presence of anti-endothelial cell antibodies in patients with idiopathic or SSc associated PAH. METHODS: PAH was confirmed by right heart catheterisation (mean pulmonary artery pressure at rest >25 mm Hg). Serum IgG and IgM reactivities were analysed by immunoblotting on human macrovascular and microvascular lung and dermal endothelial cells from patients with IPAH (n = 35), patients with PAH associated with SSc (n = 10), patients with diffuse (n = 10) or limited cutaneous (n = 10) SSc without PAH, and 65 age and sex matched healthy individuals. RESULTS: IgG antibodies from patients with IPAH bound to a 36 kDa band in macrovascular endothelial cell extracts with a higher intensity than IgG from other patient groups and controls. IgG antibodies from patients with IPAH bound more strongly to a 58 kDa band in microvascular dermal endothelial cells and to a 53 kDa band in microvascular lung endothelial cells than IgG antibodies from other patients and controls. IgG antibodies from patients with limited cutaneous SSc with or without PAH, but not from other groups or from healthy controls, bound to two major bands (75 kDa and 85 kDa) in microvascular endothelial cells. CONCLUSION: IgG antibodies from patients with idiopathic or SSc associated PAH express distinct reactivity profiles with macrovascular and microvascular endothelial cell antigens.

Adult↗
PubMed2005

Smooth muscle cell matrix metalloproteinases in idiopathic pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) results from persistent vasoconstriction, smooth muscle growth and extracellular matrix (ECM) remodelling of pulmonary arteries (PAs). Matrix metalloproteinases (MMPs) are matrix-degrading enzymes involved in ECM turnover, and in smooth muscle cell (SMC) and endothelial cell migration and proliferation. MMP expression and activity are increased in experimental PAH. Therefore, this study investigated whether similar changes occur in idiopathic PAH (IPAH; formerly known as primary pulmonary hypertension). Both in situ and in vitro studies were performed on PAs from patients undergoing lung transplantation for IPAH and from patients treated by lobectomy for localised lung cancer, who served as controls. In IPAH, MMP-tissue inhibitor of metalloproteinase (TIMP) imbalance was found in cultured PA-SMCs, with increased TIMP-1 and decreased MMP-3. MMP-2 activity was markedly elevated as a result of increases in both total MMP-2 and proportion of active MMP-2. In situ zymography and immunolocalisation showed that MMP-2 was associated with SMCs and elastic fibres, and also confirmed the MMP-3-TIMP-1 imbalance. In conclusion, the findings of this study were consistent with a role for the matrix metalloproteinase-tissue inhibitor of metalloproteinase system in pulmonary vascular remodelling in idiopathic pulmonary arterial hypertension. The matrix metalloproteinase-tissue inhibitor of metalloproteinase imbalance may lead to matrix accumulation, and increased matrix metalloproteinase-2 activity may contribute to smooth muscle cell migration and proliferation. Whether these abnormalities are potential therapeutic targets deserves further investigation.

Cells, Cultured↗
PubMed2005

N-terminal-pro-brain natriuretic peptide as a haemodynamic marker in idiopathic pulmonary arterial hypertension.

Patients with idiopathic pulmonary arterial hypertension usually undergo acute vasodilator tests with nitric oxide (NO) for haemodynamic evaluation and therapeutical planning. The aim of this study was to evaluate the link between the variation of N-terminal (NT)-pro-brain natriuretic peptide (BNP) levels and haemodynamic parameters during the acute vasodilator test. A total of 22 idiopathic pulmonary arterial hypertension patients who underwent acute vasodilator tests were studied. Blood samples were collected at baseline and after 30 and 60 min of NO inhalation. NT-pro-BNP levels were measured in each sample. A receiver-operating characteristic curve was used to evaluate the capability of the NT-pro-BNP level variation during NO inhalation in recognising nonresponders. To distinguish responders from nonresponders, the increase of the NT-pro-BNP (0% as cut-off value) determined a 50% specificity and 100% sensitivity (positive predictive value of 38% and a negative predictive value of 100%). These results suggest that N-terminal-pro-brain natriuretic peptide was able to distinguish nonresponder patients with the acute vasodilator test. N-terminal-pro-brain natriuretic peptide may be an interesting additional biological tool in the evaluation of idiopathic pulmonary arterial hypertension patients.

Adult↗