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Olivier Sitbon

Publications and source records attributed to Olivier Sitbon.

At least 19 recordsLinked to original sources
PubMed2026

Beyond Heritable PAH: Pulmonary Hypertension in Genetic Syndromes.

Pulmonary hypertension (PH) may complicate a broad range of genetic syndromes beyond the established spectrum of heritable pulmonary arterial hypertension. Although these conditions are individually rare, together they represent an emerging field at the crossroads of developmental biology, vascular medicine, and precision genomics. In many cases, PH may be the presenting feature or may remain unrecognized because it occurs within complex multisystem disorders involving congenital heart disease, developmental lung abnormalities, parenchymal lung disease, vascular malformations, or extra-pulmonary manifestations. Recent advances in human genetics have expanded the spectrum of genes and syndromes associated with PH, including disorders involving altered lung and vascular development, dysregulated hypoxia signaling, smooth muscle dysfunction, chromosomal abnormalities, and syndromic vasculopathies.In this review, we summarize the main genetic syndromes associated with PH and discuss their underlying mechanisms, clinical phenotypes, diagnostic clues, and therapeutic implications. We paid particular attention to conditions that illustrate the marked heterogeneity of syndromic PH such as FLNA-related disorders, neurofibromatosis type 1, Noonan syndrome, Down syndrome, Alagille syndrome, Cantú syndrome, Chuvash polycythaemia, cobalamin C deficiency, multisystemic smooth muscle dysfunction syndrome, alveolar capillary dysplasia with misalignment of pulmonary veins, and Moya Moya syndrome.

Journal Article↗
PubMed2007

Pulmonary vascular abnormalities in cirrhosis.

Two pulmonary vascular disorders can occur in liver disease and/or portal hypertension: the hepatopulmonary syndrome (HPS), which is characterized by intrapulmonary vascular dilatations, and portopulmonary hypertension (POPH), in which pulmonary vascular resistance is elevated. POPH and HPS are characterized by distinct pulmonary microvascular remodelling, which occurs at different anatomical sites of the pulmonary microcirculation. The exact pathophysiological mechanisms of these pulmonary vascular disorders are unknown. However, as HPS and POPH have been reported in patients with extrahepatic portal hypertension, the factor that determines their development must be portal hypertension. The clinical presentations are very different, with gas exchange impairment in HPS and hemodynamic failure in POPH. The severity of HPS seems to parallel the severity of liver failure, whereas no simple relationship has been identified between hepatic impairment and the severity of POPH. Resolution of HPS is common after liver transplantation, which has an uncertain effect in POPH.

Diagnosis, Differential↗
PubMed2006

Pulmonary arterial hypertension in France: results from a national registry.

RATIONALE: Pulmonary arterial hypertension (PAH) is an orphan disease for which the trend is for management in designated centers with multidisciplinary teams working in a shared-care approach. OBJECTIVE: To describe clinical and hemodynamic parameters and to provide estimates for the prevalence of patients diagnosed for PAH according to a standardized definition. METHODS: The registry was initiated in 17 university hospitals following at least five newly diagnosed patients per year. All consecutive adult (> or = 18 yr) patients seen between October 2002 and October 2003 were to be included. MAIN RESULTS: A total of 674 patients (mean +/- SD age, 50 +/- 15 yr; range, 18-85 yr) were entered in the registry. Idiopathic, familial, anorexigen, connective tissue diseases, congenital heart diseases, portal hypertension, and HIV-associated PAH accounted for 39.2, 3.9, 9.5, 15.3, 11.3, 10.4, and 6.2% of the population, respectively. At diagnosis, 75% of patients were in New York Heart Association functional class III or IV. Six-minute walk test was 329 +/- 109 m. Mean pulmonary artery pressure, cardiac index, and pulmonary vascular resistance index were 55 +/- 15 mm Hg, 2.5 +/- 0.8 L/min/m(2), and 20.5 +/- 10.2 mm Hg/L/min/m(2), respectively. The low estimates of prevalence and incidence of PAH in France were 15.0 cases/million of adult inhabitants and 2.4 cases/million of adult inhabitants/yr. One-year survival was 88% in the incident cohort. CONCLUSIONS: This contemporary registry highlights current practice and shows that PAH is detected late in the course of the disease, with a majority of patients displaying severe functional and hemodynamic compromise.

Adolescent↗
PubMed2006

Long-term outcome with first-line bosentan therapy in idiopathic pulmonary arterial hypertension.

AIMS: Data on long-term efficacy of bosentan in unselected idiopathic pulmonary arterial hypertension (IPAH) patients are lacking. We aimed to describe the long-term outcome of consecutive IPAH patients treated first-line with bosentan. METHODS AND RESULTS: A retrospective analysis of 103 consecutive New York Heart Association functional class III/IV IPAH patients treated with bosentan at our centre between November 1999 and May 2004 was performed. The 6-minute walk distance (6MWD) and haemodynamics were assessed at baseline and after 4 and 12 months. Mean follow-up was 24+/-15 months. At 4 months, significant improvements in exercise capacity and haemodynamics were observed and persisted up to 1 year. Overall survival estimates were 90 and 87% and event-free status (survival without transplantation, prostanoid initiation, or hospitalization for right heart failure) estimates were 61 and 44% at 1 and 2 years, respectively. Forty-five (44%) patients required prostanoid therapy during follow-up. The 6MWD and the right atrial pressure at baseline and the 6MWD, the increase in 6MWD, and the decrease in pulmonary resistance after 4 months of treatment were associated with long-term outcomes. CONCLUSION: In our series of consecutive IPAH patients treated with bosentan, improvements in exercise capacity and haemodynamics were similar to those observed in previous randomized trials. However, on the basis of local criteria, many patients required the addition of prostanoid therapy during follow-up.

Adolescent↗
PubMed2006

Mutations of the TGF-beta type II receptor BMPR2 in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is clinically characterized by a sustained elevation in mean pulmonary artery pressure leading to significant morbidity and mortality. The disorder is typically sporadic, and in such cases the term idiopathic PAH (IPAH) is used. However, cases that occur within families (familial PAH (FPAH)) display similar clinical and histopathological features, suggesting a common etiology. Heterozygous mutations of a type II member of the TGF-beta cell signaling superfamily known as BMPR2 on chromosome 2q33 have been identified in many kindreds with FPAH, yet display both reduced penetrance and sex bias. This report presents the compilation of data for 144 distinct mutations that alter the coding sequence of the BMPR2 gene identified in 210 independent PAH subjects. This large data set characterizes the extent of sequence variation and reveals that the majority (71%) of mutations in FPAH and IPAH comprise nonsense, frameshift, and splice-site defects, and gene rearrangements. These predict premature termination of the transcript with likely loss through the process of nonsense-mediated decay (NMD). A total of 44 missense mutations were identified that substitute amino acid residues at highly conserved sites within recognized functional domains of the mature receptor. We assess this category of mutations in the context of their heterogeneous effects on cell signaling when assayed by in vitro cell-based systems. Disease-causing mutation hot-spots within BMPR2 are summarized. Taken together, these observations are likely to aid in the development of targeted mutation detection strategies relevant for patient management. Finally, we examine the age- and sex-dependent reduced penetrance of BMPR2 mutations by reviewing bmpr2 animal models and the requirement for additional genetic and/or environmental modifiers of disease. In conclusion, these data provide compelling genetic evidence that haploinsufficiency is the predominant molecular mechanism underlying disease predisposition, and support the concept of a critical threshold of signaling activity below which disease may be precipitated.

Bone Morphogenetic Protein Receptors, Type II↗
PubMed2006

Deleterious effects of beta-blockers on exercise capacity and hemodynamics in patients with portopulmonary hypertension.

BACKGROUND & AIMS: It has been suggested that beta-blockers might be harmful in pulmonary arterial hypertension. However, no study has evaluated the effect of beta-blockers in these patients. The aim of this study was to investigate the effect of beta-blockers on exercise capacity and pulmonary hemodynamics in patients with portopulmonary hypertension receiving beta-blockers for the prophylaxis of variceal bleeding. METHODS: Ten consecutive patients with moderate to severe portopulmonary hypertension (mean pulmonary artery pressure of 52 [10] mm Hg) underwent a 6-minute walk test and a right heart catheterization at baseline and 2 (1) months after beta-blocker withdrawal. RESULTS: Following beta-blocker withdrawal, 9 of 10 patients increased their 6-minute walked distance with a mean increase in the whole group of 79 (78) meters (P = .01). Cardiac output increased by 28% (P < .01) with no change in mean pulmonary artery pressure, resulting in a 19% decrease in pulmonary vascular resistance (P < .01). Increases in cardiac output were related to a 25% increase in heart rate (P < .01), whereas stroke volume was unchanged (P = .65). The improvements in exercise tolerance were associated with increases in chronotropic response (maximal heart rate minus resting heart rate) from 18 (9) to 34 (12) beats/min (P < .01) during the 6-minute walk test. CONCLUSIONS: In patients with moderate to severe portopulmonary hypertension, beta-blockers are associated with significant worsening in exercise capacity and pulmonary hemodynamics. These deleterious effects support the contraindication of beta-blockers in patients with portopulmonary hypertension.

Adrenergic beta-Antagonists↗
PubMed2006

Immunosuppressive therapy in connective tissue diseases-associated pulmonary arterial hypertension.

STUDY OBJECTIVE: Immune and inflammatory mechanisms could play a significant role in pulmonary arterial hypertension (PAH) genesis or progression, especially in patients with connective tissue diseases. Immunosuppressive therapy should be better evaluated in this setting. STUDY DESIGN: Monocentric retrospective study. PATIENTS: We reviewed the clinical and hemodynamic effects of immunosuppressants administered as first-line monotherapy to 28 consecutive patients with connective tissue disease-associated PAH. INTERVENTIONS: All patients received a monthly IV bolus of cyclophosphamide, 600 mg/m2, for at least 3 months, and 22 of 28 patients received systemic glucocorticosteroids. Responders to immunosuppressive therapy were defined as patients who remained in New York Heart Association (NYHA) functional class I or II with sustained hemodynamic improvement after at least 1 year of immunosuppressive therapy without addition of prostanoids, phosphodiesterase type 5 inhibitors, or endothelin receptor antagonists. RESULTS: Eight of 28 patients (systemic lupus erythematosus [SLE], n = 5; mixed connective tissue disease [MCTD], n = 3) [29%] were responders. These patients had a significantly improved 6-min walking distance (available in five patients) and a significant improvement in hemodynamic function. No patients with systemic sclerosis responded, while 5 of 12 patients with SLE and 3 of 8 patients with MCTD did respond. Survival analysis indicated that responders had a better survival than nonresponders. Patients with a lower baseline NYHA functional class and better baseline pulmonary hemodynamics (p < 0.05) were more likely to benefit from immunosuppressive therapy. CONCLUSION: PAH associated with SLE or MCTD might respond to a treatment combining glucocorticosteroids and cyclophosphamide.

Adult↗
PubMed2005

Long-term response to calcium channel blockers in idiopathic pulmonary arterial hypertension.

BACKGROUND: Characteristics of patients with idiopathic pulmonary arterial hypertension (IPAH) who benefit from long-term calcium channel blockers (CCB) are unknown. METHODS AND RESULTS: Acute pulmonary vasodilator testing with epoprostenol or nitric oxide was performed in 557 IPAH patients. Acute responders, defined by a fall in both mean pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) >20%, received long-term oral CCB. Patients who benefit from long-term CCB were defined as those being in New York Heart Association (NYHA) functional class I or II after at least 1 year on CCB monotherapy. Among the 70 patients who displayed acute pulmonary vasoreactivity (12.6%; 95% CI, 9.8% to 15.3%) and received CCB therapy, only 38 showed long-term improvement (6.8%; 95% CI, 4.7% to 8.9%). Long-term CCB responders had less severe disease at baseline than patients who failed. During acute vasodilator testing, long-term CCB responders displayed a more pronounced fall in mean PAP (-39+/-11% versus -26+/-7%; P<0.0001), reaching an absolute value of mean PAP lower than that measured in patients who failed (33+/-8 versus 46+/-10 mm Hg; P<0.0001). After 7.0+/-4.1 years, all but 1 long-term CCB responders were alive in NYHA class I or II, with a sustained hemodynamic improvement. In the group of patients who failed on CCB, the 5-year survival rate was 48%. CONCLUSIONS: Long-term CCB responders represent <10% of IPAH patients evaluated in a pulmonary vascular referral center. During acute vasodilator testing, these patients showed significantly lower levels of both mean PAP and PVR, which reached near-normal values.

Adult↗
PubMed2005

Severe pulmonary hypertension during pregnancy: mode of delivery and anesthetic management of 15 consecutive cases.

BACKGROUND: Available literature on pregnant women with severe pulmonary hypertension (PH) relies mainly on anecdotal case reports and two series only. METHODS: The authors reviewed the charts of all pregnant women with severe PH who were followed up at their institution during the past 10 yr, to assess the multidisciplinary treatment and outcome of these patients. RESULTS: Fifteen pregnancies in 14 women with severe PH were managed during this period: There were 4 cases of idiopathic pulmonary arterial hypertension (PAH), 6 cases of congenital heart disease-associated PAH, 1 case of fenfluramine-associated PAH, 1 case of mixed connective tissue-associated PAH, 1 case of human immunodeficiency virus-associated PAH, and 2 cases of chronic thromboembolic PH. PH presented during pregnancy in 3 patients. Two patients died before delivery at 12 and 23 weeks' gestation. Four patients had vaginal deliveries with regional anesthesia: One died 3 months postpartum, one worsened, and two remained stable. Four had cesarean deliveries during general anesthesia: One died 3 weeks postpartum, one worsened, and two remained stable. Five had cesarean deliveries during low-dose combined spinal-epidural anesthesia: One died 1 week postpartum, and four remained stable. There were two fetal deaths: one related to therapeutic abortion at 21 weeks' gestation and one stillbirth at 36 weeks' gestation followed by the death of the mother 1 week later. CONCLUSIONS: Despite the most modern treatment efforts, the maternal mortality was 36%. Scheduled cesarean delivery during combined spinal-epidural anesthesia seemed to be an attractive approach, but there was no evidence of actual benefit. Therefore, pregnancy must still be discouraged in patients with severe PH.

Adult↗
PubMed2005

Clinical challenges in pulmonary hypertension: Roger S. Mitchell lecture.

Despite major advances in our understanding of the pathophysiologic processes leading to pulmonary arterial hypertension and recent developments in therapeutic approaches, the long-term prognosis for patients with pulmonary arterial hypertension remains unsatisfactory. Early detection and adequate clinical classification of the disease, better assessment of patients' prognosis, and improved therapeutic strategies are important challenges for clinicians in coming years.

Humans↗
PubMed2005

Treatment of pulmonary arterial hypertension with bosentan: from pathophysiology to clinical evidence.

In addition to its potent vasoconstricting effect, endothelin (ET)-1 induces proliferation of pulmonary vascular cells and appears to play a pathogenic role in the development of pulmonary arterial hypertension (PAH). Blockade of the ET receptors has been proposed for the treatment of this condition. Bosentan (Tracleer, Actelion Pharmaceuticals), an oral ETA/ETB receptor antagonist, has been shown to improve exercise capacity, quality of life, haemodynamics and time to clinical worsening of patients with PAH in short-term placebo-controlled trials. These improvements were sustained, and a long-term observational study on idiopathic PAH patients suggested a favourable effect on survival in this subset. In the present report, the pharmacology, clinical efficacy and safety profile of bosentan are summarised. The place of bosentan among the current therapies available for the treatment of PAH is also discussed.

Antihypertensive Agents↗
PubMed2005

Idiopathic pulmonary hypertension: what did we learn from genes?

Pulmonary arterial hypertension (PAH) is an uncommon disorder. PAH can be idiopathic, associated with other conditions or clustered in families. Indeed, at least 6% of individuals diagnosed with so-called "primary" pulmonary hypertension have a family history of the disorder. Familial PAH segregates as an autosomal dominant trait but with markedly reduced penetrance. Defects within bone morphogenetic protein receptor type II gene (BMPR2), coding for a type II receptor member of the transforming growth factor beta (TGF-beta) family, have been shown to underlie familial PAH. Germline BMPR2 mutations have been detected in at least 60% of the families studied to date. Disease-associated mutations are predicted to interrupt the BMP-mediated signalling pathway predisposing to proliferation of cells within small pulmonary arteries. Several lines of evidence point to the potential requirement of additional factors, either environmental or genetic, in the pathogenesis of the disease. In addition, a proportion of idiopathic PAH as well as anorexigen-associated PAH turn out to have an inherited basis, as demonstrated by detection of germline BMPR2 mutations. Analysis of other genes encoding TGF-beta receptor proteins, led to the demonstration that PAH in association with hereditary hemorrhagic telangiectasia, an autosomal dominant vascular dysplasia, can involve other TGF-beta receptor subtypes. These observations support the hypothesis that mutations in the TGF-beta superfamily may be a trigger for pulmonary vascular remodeling. Nevertheless, PAH pathobiology remains unclear and genomic approaches may identify additional molecular determinants for this disorder.

Bone Morphogenetic Protein Receptors, Type II↗
PubMed2004

Bosentan for the treatment of human immunodeficiency virus-associated pulmonary arterial hypertension.

Clinical studies have shown the importance of endothelin as a pathogenic mediator in pulmonary arterial hypertension (PAH). We describe the effects of bosentan, an oral dual endothelin receptor antagonist, in patients with PAH associated with human immunodeficiency virus (HIV) infection. In this prospective study, 16 patients with PAH associated with HIV infection in stable condition received bosentan for 16 weeks. Efficacy endpoints included exercise capacity, cardiopulmonary hemodynamics, Doppler echocardiography, New York Heart Association functional class, and quality of life (SF-36 and EQ-5D). Safety was assessed by laboratory tests, vital signs, and adverse events. Improvements were observed from baseline to Week 16 in all efficacy parameters: 6-minute walk distance (+91 +/- 60 m, p < 0.001), New York Heart Association class (14 patients improved), hemodynamics (cardiac index: +0.9 +/- 0.7 L/minute/m(2), p < 0.001), Doppler echocardiographic variables, and quality of life. During the study, no patient died and none required epoprostenol treatment. Hepatic tolerability was similar to that reported in patients with PAH. Bosentan had no negative impact on control of HIV infection. Although limited by uncontrolled design, small sample size and short duration, this study suggests that bosentan may benefit patients with PAH associated with HIV infection, and that endothelin is an important pathogenic mediator in this disease.

Adult↗
PubMed2004

Diagnosis and differential assessment of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is diagnosed by various investigations that are essential for making the diagnosis, and by additional tests to clarify the category of pulmonary hypertension (PH). A diagnostic algorithm can guide the evaluation of PH, but like all guidelines the algorithm can be modified according to specific clinical circumstances. Most patients are diagnosed as the result of an evaluation of symptoms, whereas others are diagnosed during screening of asymptomatic populations at risk. Right heart catheterization (RHC) must be performed in patients with suspected PH to establish the diagnosis and document pulmonary hemodynamics. Before initiation of medical therapy, assessment of acute vasoreactivity (during catheterization) is necessary to determine the appropriate therapy for an individual patient. An acute response is generally defined as a decrease in mean pulmonary arterial pressure of at least 10 mm Hg with the mean pulmonary arterial pressure decreasing to 40 mm Hg or below, accompanied by a normal or high cardiac output. After PAH is diagnosed, disease severity should be assessed in order to accurately determine risk:benefit profiles for various therapeutic options. Useful tools to predict outcome include functional class, exercise capacity, pulmonary hemodynamics, acute vasoreactivity, right ventricular function, as well as brain natriuretic peptide, endothelin-1, uric acid, and troponin levels. Repeating these tests serially on treatment is useful for monitoring the response to a given therapy. Close follow-up at a center specializing in management of PH is recommended, with careful periodic reassessment and adjustment of therapy.

Diagnosis, Differential↗
PubMed2004

Prostanoid therapy for pulmonary arterial hypertension.

Prostanoids have played a prominent role in the treatment of pulmonary arterial hypertension (PAH). Several compounds and methods of administration have been studied: chronic intravenously infused epoprostenol, chronic subcutaneously infused treprostinil, inhaled iloprost, and oral beraprost. Chronic intravenous epoprostenol therapy has had a substantial impact on the clinical management of patients with severe PAH. It improves exercise capacity, hemodynamics, and survival in patients with idiopathic pulmonary arterial hypertension (IPAH). It also improves exercise capacity and hemodynamics in patients with PAH occurring in association with scleroderma. The complexity of epoprostenol therapy (chronic indwelling catheters, reconstitution of the drug, operation of the infusion pump, and others) has led to attempts to develop other prostanoids with simpler modes of delivery. Treprostinil, a stable prostacyclin analogue with a half-life of 3 h, has been developed for subcutaneous delivery. It has beneficial effects on exercise and hemodynamics, which depend somewhat on the dose achieved. This, in turn, is determined by the patient's ability to tolerate the drug's side effects, including pain and erythema at the infusion site. Inhaled iloprost therapy may provide selectivity of the hemodynamic effects to the lung vasculature, thus avoiding systemic side effects. In a randomized and controlled trial, iloprost resulted in improvement in a combined end point incorporating the New York Heart Association functional class, 6-min walk test, and deterioration or death. Beraprost is the first orally active prostacyclin analogue. In the first of two randomized controlled trials, beraprost increased exercise capacity in patients with IPAH, with no significant changes in subjects with associated conditions. Hemodynamics did not change significantly, and no difference in survival was detected between the two treatment groups. The second study showed that beraprost-treated patients had less disease progression at six months and confirmed the results of the previous trial. However, this improvement was no longer present at 9 or 12 months. In conclusion, though treatment with prostanoids is complicated by their generally short half-lives and complicated drug delivery systems, they continue to play an important role in the treatment of PAH.

Antihypertensive Agents↗
PubMed2004

Endothelin receptor antagonists in pulmonary arterial hypertension.

Endothelin receptor antagonism has emerged as an important therapeutic strategy in pulmonary arterial hypertension (PAH). Laboratory and clinical investigations have clearly shown that endothelin (ET)-1 is overexpressed in several forms of pulmonary vascular disease and likely plays a significant pathogenetic role in the development and progression of pulmonary vasculopathy. Oral endothelin receptor antagonists (ERAs) have been shown to improve pulmonary hemodynamics, exercise capacity, functional status, and clinical outcome in several randomized placebo-controlled trials. Bosentan, a dual-receptor antagonist, is approved by the U.S. Food and Drug Administration for class III and IV patients with PAH, based on two phase III trials. In addition to its efficacy as sole therapy, bosentan may have a role as part of a combination of drugs such as a prostanoid or sildenafil. The selective endothelin receptor-A antagonists sitaxsentan and ambrisentan are currently undergoing investigation.

Endothelin Receptor Antagonists↗