Marilyne Lévy

Circulating Endothelial Cells A New Candidate Biomarker of Irreversible Pulmonary Hypertension Secondary to Congenital Heart Disease

Background— Congenital heart disease can be complicated by pulmonary arterial hypertension (PAH), the reversibility of which is often difficult to predict. We recently reported a lung biopsy study showing impaired apoptotic regulation of endothelial cells in irreversible PAH. The objective of the present study was to identify noninvasive biomarkers of endothelial turnover that could be used to identify congenital heart disease patients at risk of irreversible PAH. Methods and Results— Circulating endothelial cells (CECs) isolated with CD146-coated beads and circulating CD34+CD133+ progenitor cells (CPCs) were quantified in peripheral vein, pulmonary artery, and pulmonary vein blood samples from 26 patients with congenital heart disease (16 with reversible PAH [median age 2 years] and 10 with irreversible PAH [median age 9 years]) and 5 control patients. Surgical lung biopsy was performed in 19 cases. As expected, endothelial remodeling was observed in irreversible PAH but not in reversible PAH. CEC and CPC numbers were each similar in the 3 types of blood samples. CEC numbers were significantly higher in patients with irreversible PAH (median 57 CEC/mL) than in patients with reversible PAH and control subjects (median 3 CEC/mL in the 2 groups). In contrast, CPC numbers did not differ among patients with irreversible or reversible PAH and control subjects (median 84, 64, and 44 CPC/105 lymphocytes, respectively, in the 3 groups). Conclusions— Irreversible PAH in congenital heart disease is associated with endothelial damage and with increased circulating endothelial cell counts. The present study suggests that CECs could be a valuable tool to define therapeutic strategies in congenital heart disease patients with PAH.

Add-On Therapy with Subcutaneous Treprostinil for Refractory Pediatric Pulmonary Hypertension

OBJECTIVE To evaluate the efficacy and tolerability of subcutaneous (SC) treprostinil, a prostacyclin analogue, in young children with refractory pulmonary arterial hypertension. STUDY DESIGN Eight children (median age, 4 years) received SC treprostinil therapy after failure of combined oral treatment (n = 7) or because of severe complications with intravenous epoprostenol (n = 1). Treprostinil was delivered through an SC catheter at gradually increasing doses to an average of 40 ng/kg/min, depending on the presence of adverse effects. RESULTS Seven patients demonstrated early significant improvement (in functional class, hemodynamics, and/or 6-minute walk distance; P <.05), and 6 had a sustained good response. Site pain could be effectively managed in all but one child. CONCLUSIONS Treprostinil may be a potentially valuable rescue therapy in children with refractory pulmonary arterial hypertension, but further study in a larger number of patients is needed.

Palliative Potts shunt for the treatment of children with drug-refractory pulmonary arterial hypertension: updated data from the first 24 patients

OBJECTIVES Palliative Potts shunt has been proposed in children with suprasystemic pulmonary arterial hypertension (PAH). METHODS A retrospective multicentre study was performed to assess short- and long-term outcomes after Potts shunt. RESULTS From 2003 to 2014, 24 children underwent a Potts shunt [19 surgical, median age: 7.7 years (1.5-17 years), median weight: 19.5 kg (10.2-47 kg) and 5 transcatheter, median age: 8.1 years (2.3-9.7 years), median weight: 22 kg (12.5-31 kg)] for drug-refractory PAH. For the first time in humans, we performed an unidirectional valved Potts anastomosis in a child with infrasystemic PAH on intravenous epoprostenol who experienced repeated central line infections. Severe postoperative complications occurred in 6 patients (25.0%, all from the surgical group) including 3 early deaths (12.5%) related to low cardiac output. After a median follow-up (FU) of 2.1 years (range, 3 months to 14.3 years, ≥8 years in 7 patients), World Health Organization (WHO) functional class was dramatically improved in the 21 survivors, all being in WHO-functional class 1 or 2 (P < 0.05); none experienced syncope during the FU; none had overt right ventricular failure; mean 6-min walk distance improved from 42.3 ± 10.0% to 81.2 ± 9.7% of adjusted values for age and sex (P < 0.001), BNP/NT-proBNP levels normalized in all; and weaning of intravenous epoprostenol was obtained in all patients who received triple combination as pre-Potts anastomosis therapy. Finally, all survivors caught up to normal growth curves. Arterial oxygen saturation gradient between upper and lower limbs persisted at the last FU (94.7 ± 3.6% vs 81.6 ± 5.1%, P < 0.001). One patient required double lung transplantation 6 years after a surgical Potts shunt. CONCLUSIONS Palliative Potts shunt allows prolonged survival and dramatic, long-lasting improvement in functional capacities in children with severe, drug-refractory PAH. The Potts shunt might be considered as a first surgical or interventional step in the management of children with severe, drug-refractory PAH, leaving the door open for further lung transplantation, if needed.

Bi-directional cavopulmonary shunt: is accessory pulsatile flow, good or bad?

OBJECTIVE Evaluation of the effect and long-term outcome of accessory pulsatile blood flow versus classical bi-directional cavopulmonary connection (BCPC). METHODS Retrospective review of the medical and surgical records. RESULTS Two-hundred and five patients (119 boys, 86 girls) underwent BCPC from 1990 to 1996. Accessory pulsatile flow was present in 68%, flow being maintained through the pulmonary trunc in 46%, systemic-to-pulmonary artery shunt in 13% and mixed in 7%, or patent ductus arteriosus in 2%. Patients with accessory pulsatile flow had lower hospital mortality (3% versus 5%), while mean pulmonary artery pressure (14.1 versus 12.6 mmHg P = 0.050) and increase of oxygen saturation (12.4 versus 8.7, P = 0.034) were significantly higher. The period of artificial ventilation (1.9 day) and ICU stay (6 days) did not differ for both groups. Late mortality was higher following accessory pulsatile flow (6% versus 1%). At late follow-up patients with accessory pulsatile flow had significantly higher oxygen saturation (mean 85 +/- 4%, versus 79 +/- 4%; P < or = 0.005). If subsequent completion of Fontan is considered the optimal palliation and subsequent systemic to pulmonary artery shunt, arteriovenous fistula and transplantation is considered a failure, patients with accessory pulsatile flow had significantly more and earlier completion of the Fontan procedure (mean 1.7 +/- 2.4 years, versus 2.7 +/- 4.4 years; P = 0.008). Survival is not influenced by age at bi-directional cavopulmonary shunt surgery, left or right functional ventricular anatomy or previous palliative surgery. One patient with accessory pulsatile flow developed systemic-to-pulmonary collaterals eventually requiring lobectomy. CONCLUSION Despite two different initial palliative techniques the outcome was not significantly different. Accessory pulsatile blood flow appeared not to be a contra-indication for a completion Fontan procedure. Moreover, the data suggest that after accessory pulsatile flow can safely be performed, at late follow-up oxygen saturation is higher, while, significantly more and earlier completion of Fontan occurred. Age at bi-directional cavopulmonary shunt, basic left or right ventricular anatomy or previous palliative surgery did not influence survival.

Patent Ductus Arteriosus Stenting (Transcatheter Potts Shunt) for Palliation of Suprasystemic Pulmonary Arterial Hypertension A Case Series

Idiopathic pulmonary arterial hypertension (IPAH) continues to be a progressive and fatal disease.1 Patients with congenital heart disease and PAH constitute a separate subset with Eisenmenger syndrome where the life expectancy is significantly better than patients with IPAH. Prior surgical series have reported improved survival after converting severe and refractory IPAH into an Eisenmenger physiology using a Potts shunt with direct side-to-side anastomosis.2–4 We describe a similar approach using a transcatheter technique by stenting residual or probe-patent ductus arteriosus (PDA) to establish a stable communication between descending thoracic aorta and left pulmonary artery in patients with severe suprasystemic PAH. During the past 5 years, we have performed cardiac catheterization in 28 IPAH patients and found 4 with a small or probe-patent PDA. One of these patients had infrasystemic PA pressures and did not undergo PDA stenting. The other 3 patients, whose data are summarized in the Table, had the PDA stented. Patient 1 was diagnosed with idiopathic PAH at the age of 6 months. Transthoracic echocardiography at the time of the diagnosis showed an atrial septal defect with left-to-right shunt and a small PDA. He remained stable on oral medications until 9.7 years of age when he presented with recurrent syncope. Severe right ventricular dilatation and bowing of the interventricular septum to the left were noted on transthoracic echocardiogram. Cardiac catheterization confirmed suprasystemic PAH and the presence of a small PDA shunting right-to-left with significant restriction (Figure 1). Figure 1. Angiographic views from the first case. A , Aortography in lateral view, showing …

Clinical phenotypes and outcomes of heritable and sporadic pulmonary veno-occlusive disease: a population-based study

BACKGROUND Bi-allelic mutations of the EIF2AK4 gene cause heritable pulmonary veno-occlusive disease and/or pulmonary capillary haemangiomatosis (PVOD/PCH). We aimed to assess the effect of EIF2AK4 mutations on the clinical phenotypes and outcomes of PVOD/PCH. METHODS We did a population-based study using clinical, functional, and haemodynamic data from the registry of the French Pulmonary Hypertension Network. We reviewed the clinical data and outcomes from all patients referred to the French Referral Centre (Pulmonary Department, Hospital Kremlin-Bicêtre, University Paris-Sud) with either confirmed or highly probable PVOD/PCH with DNA available for mutation screening (excluding patients with other risk factors of pulmonary hypertension, such as chronic respiratory diseases). We sequenced the coding sequence and intronic junctions of the EIF2AK4 gene, and compared clinical characteristics and outcomes between EIF2AK4 mutation carriers and non-carriers. Medical therapies approved for pulmonary arterial hypertension (prostacyclin derivatives, endothelin receptor antagonists and phosphodiesterase type-5 inhibitors) were given to patients according to the clinical judgment and discretion of treating physicians. The primary outcome was the event-free survival (death or transplantation). Secondary outcomes included response to therapies for pulmonary arterial hypertension and survival after lung transplantation. A satisfactory clinical response to specific therapy for pulmonary arterial hypertension was defined by achieving New York Heart Association functional class I or II, a 6-min walk distance of more than 440 m, and a cardiac index greater than 2·5 L/min per m2 at the first reassessment after initiation of specific therapy for pulmonary arterial hypertension. FINDINGS We obtained data from Jan 1, 2003, to June 1, 2016, and identified 94 patients with sporadic or heritable PVOD/PCH (confirmed or highly probable). 27 (29%) of these patients had bi-allelic EIF2AK4 mutations. PVOD/PCH due to EIF2AK4 mutations occurred from birth to age 50 years, and these patients were younger at presentation than non-carriers (median 26·0 years [range 0-50.3] vs 60·0 years [6·7-81·4] years; p<0·0001). At diagnosis, both mutations carriers and non-carriers had similarly severe precapillary pulmonary hypertension and functional impairment. 22 (81%) of mutations carriers and 63 (94%) of non-carriers received therapy approved for pulmonary arterial hypertension. Drug-induced pulmonary oedema occurred in five (23%) of treated EIF2AK4 mutations carriers and 13 (21%) of treated non-carriers. Follow-up assessment after initiation of treatment showed that only three (4%) patients with PVOD/PCH reached the predefined criteria for satisfactory clinical response. The probabilities of event-free survival (death or transplantation) at 1 and 3 years were 63% and 32% in EIF2AK4 mutations carriers, and 75% and 34% in non-carriers. No significant differences occurred in event-free survival between the 2 groups (p=0·38). Among the 33 patients who had lung transplantation, estimated post-transplantation survival rates at 1, 2, and 5 years were 84%, 81%, and 73%, respectively. INTERPRETATION Heritable PVOD/PCH due to bi-allelic EIF2AK4 mutations is characterised by a younger age at diagnosis but these patients display similar disease severity compared with mutation non-carriers. Response to therapy approved for pulmonary arterial hypertension in PVOD/PCH is rare. PVOD/PCH is a devastating condition and lung transplantation should be considered for eligible patients. FUNDING None.

Developmental Changes in Endothelial Vasoactive and Angiogenic Growth Factors in the Human Perinatal Lung

Little is known of the mechanisms underlying the marked fall in pulmonary vascular resistance that occurs at birth, but changes in the expression of endothelial vasoactive and angiogenic factors during lung development might play a key role. Nitric oxide, endothelin-1, and vascular endothelial growth factor have critical effects on vascular tone and cell growth. Here, we investigated the protein expression of endothelial nitric oxide synthase, endothelin-1 and its receptors, and vascular endothelial growth factor in pulmonary necropsy samples from 14 fetuses of different gestational ages and from 5 infants. Expression of endothelin-1 and its receptor endothelin-A was strong and stable. In contrast, expression of the endothelin-B receptor was weak in early gestation, then increased markedly in mid-gestation and remained high thereafter. The expression of endothelial nitric oxide synthase and vascular endothelial growth factor fell markedly after mid-gestation and remained low thereafter. These data point to a discrepancy between maturational and functional changes in human pulmonary vascular structures. The weak perinatal expression of endothelial nitric oxide could suggest that other potent vasodilatory mediators are responsible for the marked vasodilation observed at birth.

Developmental expression of vasoactive and growth factors in human lung. Role in pulmonary vascular resistance adaptation at birth.

The factors that mediate the postnatal fall in pulmonary vascular resistance, which is crucial for normal gas exchange, are not fully understood. The endothelium has been implicated in this phenomenon, through the release of vasorelaxant factors such as nitric oxide (NO). Human pulmonary expression of endothelial NO synthase increases up to 31 wk of gestation, together with vascular endothelial growth factor (VEGF), and both factors potently mediate pulmonary angiogenesis and vasorelaxation. During the perinatal period, when pulmonary vasodilatation is maximal, endothelial NO synthase and VEGF are weakly expressed. This raises the involvement of vasorelaxant factors other than NO at birth. One candidate is endothelial-derived hyperpolarizing factor, which induces smooth muscle cell hyperpolarization by activating KATP channels. The marked vasorelaxation induced by activation of these channels in newborn animals, and their strong perinatal expression in the human lung, suggest their involvement during this phase. Another candidate is endothelin (ET)-1, together with its receptors ET-A and ET-B. ET-A receptors are located exclusively on smooth muscle cells and mediate vasoconstriction, whereas ET-B receptors mediate vasoconstriction when located on smooth muscle cells and vasodilatation when located on endothelial cells. ET-B receptors, which are strongly expressed in the human fetal lung both at the end of gestation and after birth, may be involved in perinatal pulmonary vasodilatation. Thus, in human fetal lung, KATP channels and ET-B receptors could be important in mediating the perinatal pulmonary vasodilatation crucial for adapting the pulmonary circulation to extrauterine life.

Pulmonary vascular dysfunction in end-stage cystic fibrosis: role of NF-κB and endothelin-1

Pulmonary hypertension is rare in chronic respiratory diseases but has a strong impact on the prognosis and is partly underlined by factors other than hypoxaemia. The aim of the present study was to assess the potential role of endothelin-1 (ET-1) and nuclear factor (NF)-κB vasoconstrictive pathways in pulmonary hypertension. The effects of ET-1 receptors blockers (BQ 123 and 788) and of genistein were assessed on response to acetylcholine of pulmonary vascular rings from cystic fibrosis (CF) lung transplant recipients (n = 23). NF-κB and ET-1 receptor expression was immunodetected in pulmonary arteries and quantitated using Western blotting. ET-1 vascular content was quantitated using ELISA. In total, 14 out of 23 subjects exhibited strongly impaired pulmonary vasodilation (p<0.01 versus nine out of 23 subjects with a normal response) associated with an activation of ET-1 receptors A and NF-κB pathways. Genistein restored vasodilation in subjects with an abnormal response. Pulmonary vascular dysfunction is frequent in end-stage CF, involving the NF-κB pathway and that of ET-1 through ET-1 receptor A (ETAR). These data leave a conceptual place for ETAR blockers and isoflavones in the management of the devastating vascular complication of chronic obstructive respiratory diseases such as CF.

Circulating Endothelial Cells in Refractory Pulmonary Hypertension in Children: Markers of Treatment Efficacy and Clinical Worsening

Background Pulmonary vasodilators in general and prostacyclin analogues in particular have improved the outcome of patients with pulmonary arterial hypertension (PAH). Endothelial dysfunction is a key feature of PAH and we previously described that circulating endothelial cell (CEC) level could be used as a biomarker of endothelial dysfunction in PAH. We now hypothesized that an efficient PAH-specific vasodilator therapy might decrease CEC level. Methods/Results CECs were prospectively quantified by immunomagnetic separation with mAb CD146-coated beads in peripheral blood from children with idiopathic PAH (iPAH, n = 30) or PAH secondary to congenital heart disease (PAH-CHD, n = 30): before, after treatment and during follow up. Controls were 23 children with reversible PAH. Oral treatment with endothelin receptor antagonists (ERA) and/or phosphodiesterase 5 inhibitors (PDE5) significantly reduced CEC counts in children. In 10 children with refractory PAH despite oral combination therapy, subcutaneous (SC) treprostinil was added and we observed a significant decrease in CEC counts during the first month of such treatment. CECs were quantified during a 6 to 36 month-follow-up after initiation of SC treprostinil and we found that CEC counts changed over time, with rising counts always preceding clinical deterioration. Conclusion CECs might be useful as a biomarker during follow-up of pediatric iPAH and PAH-CHD to assess response to treatment and to anticipate clinical worsening.