Neonatal and fetal therapy of congenital diaphragmatic hernia-related pulmonary hypertension

Congenital diaphragmatic hernia (CDH) is a complex malformation characterised by a triad of pulmonary hypoplasia, pulmonary hypertension (PH) and cardiac ventricular dysfunction. Much of the mortality and morbidity in CDH is largely accounted for by PH, especially when persistent beyond the neonatal period and refractory to available treatment. Gentle ventilation, haemodynamic optimisation and pulmonary vasodilation constitute the foundations of neonatal treatment of CDH-related PH (CDH-PH). Moreover, early prenatal diagnosis, the ability to assess severity and the developmental nature of the condition generate the perfect rationale for fetal therapy. Shortcomings of currently available clinical therapies in combination with increased understanding of CDH pathophysiology have spurred experimental drug trials, exploring new therapeutic mechanisms to tackle CDH-PH. We herein discuss clinically available neonatal and fetal therapies specifically targeting CDH-PH and review the most promising experimental treatments and future research avenues.

EXPRESS: Clinical characteristics and prognosis analysis of idiopathic and hereditary pulmonary hypertension patients with ACVRL1 gene mutations

Pulmonary arterial hypertension (PAH) is a kind of heart and lung vascular disease with low incidence and poor prognosis. Genetic variants are the important factors of PAH. The mutations of activin receptor-like kinase-1 (ACVRL1) could cause pulmonary arteriole obstruction and occlusion in PAH patients. The ACVRL1 gene mutation and clinical characteristics of Chinese idiopathic or hereditary pulmonary hypertension (IPAH/HPAH) patients are still unclear. This study aimed to retrospective study the mutation characteristics of ACVRL1 gene in Chinese IPAH/HPAH patients and its effect on clinical prognosis. We analyzed the clinical, functional, hemodynamic and mutation characteristics of 12 IPAH/HPAH patients with ACVRL1 mutations, and compared with 94 IPAH/HPAH patients (27 patients carried bone morphogenetic protein receptor type 2 (BMPR2) mutations and 67 without mutations). All ACVRL1 mutations of 12 patients were single nucleotide missense mutations. The ratio of male to female in 12 patients was 1:1. The diagnosis age of ACVRL1 mutation patients was younger than that of BMPR2 mutation patients (13.6±11.3 years vs. 16.0±12.9 years), but higher than that of patients without mutations (13.6±11.3 years vs. 8.8±8.5years, P=0.006). IPAH/HPAH patients with ACVRL1 mutation have rapidly disease progresses, high overall mortality rate (approximately 50%) and no respond to the acute pulmonary vasodilation test. In conclusion, this is the first study to analyze the ACVRL1 gene mutation and clinical characteristics of Chinese IPAH/HPAH patients. It is beneficial to screen ACVRL1 gene mutation for IPAH/HPAH patients to facilitate genetic counseling and early prevention and treatment.

Resuscitation with an Intact Cord Enhances Pulmonary Vasodilation and Ventilation with Reduction in Systemic Oxygen Exposure and Oxygen Load in an Asphyxiated Preterm Ovine Model

(1) Background: Optimal initial oxygen (O2) concentration in preterm neonates is controversial. Our objectives were to compare the effect of delayed cord clamping with ventilation (DCCV) to early cord clamping followed by ventilation (ECCV) on O2 exposure, gas exchange, and hemodynamics in an asphyxiated preterm ovine model. (2) Methods: Asphyxiated preterm lambs (127–128 d) with heart rate <90 bpm were randomly assigned to DCCV or ECCV. In DCCV, positive pressure ventilation (PPV) was initiated with 30–60% O2 and titrated based on preductal saturations (SpO2) with an intact cord for 5 min, followed by clamping. In ECCV, the cord was clamped, and PPV was initiated. (3) Results: Fifteen asphyxiated preterm lambs were randomized to DCCV (N = 7) or ECCV (N = 8). The inspired O2 (40 ± 20% vs. 60 ± 20%, p < 0.05) and oxygen load (520 (IQR 414–530) vs. 775 (IQR 623–868), p-0.03) in the DCCV group were significantly lower than ECCV. Arterial oxygenation and carbon dioxide (PaCO2) levels were significantly lower and peak pulmonary blood flow was higher with DCCV. (4) Conclusion: In asphyxiated preterm lambs, resuscitation with an intact cord decreased O2 exposure load improved ventilation with an increase in peak pulmonary blood flow in the first 5 min.

Pulmonary vasodilation by sildenafil in acute intermediate-high risk pulmonary embolism: a randomized explorative trial

Background To investigate if acute pulmonary vasodilation by sildenafil improves right ventricular function in patients with acute intermediate-high risk pulmonary embolism (PE). Methods Single center, explorative trial. Patients with PE were randomized to a single oral dose of sildenafil 50 mg (n = 10) or placebo (n = 10) as add-on to conventional therapy. The time from hospital admission to study inclusion was 2.3 ± 0.7 days. Right ventricular function was evaluated immediately before and shortly after (0.5–1.5 h) randomization by right heart catheterization (RHC), trans-thoracic echocardiography (TTE), and cardiac magnetic resonance (CMR). The primary efficacy endpoint was cardiac index measured by CMR. Results Patients had acute intermediate-high risk PE verified by computed tomography pulmonary angiography, systolic blood pressure of 135 ± 18 (mean ± SD) mmHg, increased right ventricular/left ventricular ratio 1.1 ± 0.09 and increased troponin T 167 ± 144 ng/L. Sildenafil treatment did not improve cardiac index compared to baseline (0.02 ± 0.36 l/min/m2, p = 0.89) and neither did placebo (0.00 ± 0.34 l/min/m2, p = 0.97). Sildenafil lowered mean arterial blood pressure (− 19 ± 10 mmHg, p < 0.001) which was not observed in the placebo group (0 ± 9 mmHg, p = 0.97). Conclusion A single oral dose of sildenafil 50 mg did not improve cardiac index but lowered systemic blood pressure in patients with acute intermediate-high risk PE. The time from PE to intervention, a small patient sample size and low pulmonary vascular resistance are limitations of this study that should be considered when interpreting the results. Trial Registration: The trial was retrospectively registered at www.clinicaltrials.gov (NCT04283240) February 2nd 2020, https://clinicaltrials.gov/ct2/show/NCT04283240?term=NCT04283240&draw=2&rank=1.

Recent advances in the approach to hepatopulmonary syndrome and portopulmonary hypertension

Liver disease, cirrhosis and portal hypertension can be complicated by pulmonary vascular disease, which may affect prognosis and influence liver transplantation (LT) candidacy. Pulmonary vascular complications comprise hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH). Although these two conditions develop on a same background and share a common trigger, pulmonary responses are distinct and occur at different anatomical sites of the pulmonary circulation. HPS affects 10-30% of patients referred for LT, and is characterized by gas exchange abnormalities due to pulmonary vasodilation and right-to-left shunting. POPH occurs in 5%, and is defined by pulmonary arterial hypertension due to increased pulmonary vascular resistance, which leads to hemodynamic failure. Even though HPS and POPH may have a substantial negative impact on survival, both entities are clinically underrecognized and frequently misdiagnosed. Without intervention, the 5-year survival rate is 23% in HPS and 14% in POPH. Their presence should be actively sought by organized screening in patients presenting with dyspnea and in all patients on the waitlist for LT, also because clinical symptoms are commonly non-specific or even absent. LT may lead to resolution, however, advanced stages of either HPS or POPH may jeopardize safe and successful LT. This implicates the need of proper identification of HPS and POPH cases, as well as the need to be able to successfully ‘bridge’ patients to LT by medical intervention. A review article on this topic has been published in this journal in 2007 (1). This updated review focuses on recent advances in the diagnosis and management of these 2 liver-induced pulmonary vascular disorders and incorporates results from our recent work.

Pulmonary Vasodilation by Sildenafil in Acute Intermediate-High Risk Pulmonary Embolism – A Randomized Explorative Trial

Background: To investigate if acute pulmonary vasodilation by sildenafil improves right ventricular function in patients with acute intermediate-high risk pulmonary embolism (PE). Methods: Single center, explorative trial. Patients with PE were randomized to a single oral dose of sildenafil 50mg (n=10) or placebo (n=10) as add-on to conventional therapy. The time from hospital admission to study inclusion was 2.3 ± 0.7 days. Right ventricular function was evaluated immediately before and shortly after (0.5-1.5h) randomization by right heart catheterization (RHC), trans-thoracic echocardiography (TTE), and cardiac magnetic resonance (CMR). The primary efficacy endpoint was cardiac index measured by CMR. Results: Patients had acute intermediate-high risk PE verified by computed tomography pulmonary angiography, systolic blood pressure of 135 ± 18 (mean ± SD) mmHg, increased right ventricular/left ventricular ratio 1.1 ± 0.09 and increased troponin T 167 ± 144 ng/L. Sildenafil treatment did not improve cardiac index compared to baseline (0.02 ± 0.36 l/min/m2, p=0.89) and neither did placebo (0.00 ± 0.34 l/min/m2, p=0.97). Conclusion: A single oral dose of sildenafil 50 mg did not improve cardiac index but lowered systemic blood pressure in patients with acute intermediate-high risk PE. The time from PE to intervention, a small patient sample size and low pulmonary vascular resistance are limitations of this study that should be considered when interpreting the results.

Usage of Inhaled Nitric Oxides in Cases of Eisenmenger Syndrome

Eisenmenger Syndrome is congenital heart disease with pulmonary hypertension and shunting turning from right to left. The resistance of pulmonary vascular more than 7.5 mmHg/L/min. The right ventricle and pulmonary artery always enlarge. Physiological effects of inhaled nitric oxide therapy cause selective pulmonary vasodilation: Hypoxia alveoli causes reversible vasoconstriction, thereby increasing pulmonary wedge pressure. Inhaled nitric oxide can lower it. Moderate cardiac output and systematic arterial pressure are not affected; Selective in pulmonary because it is activated by hemoglobin; Selective vasodilation in the ventilated area, local hypoxia alveoli constricts the surrounding vascular tissue and redistributes blood flow to the ventilated lungs better and higher intraalveolar oxygen pressure. Inhaled nitric oxide enhances this mechanism by increasing blood flow through a well-ventilated lung; Bronchodilators; Pulmonary surfactant, The combination of high concentrations of inspired oxygen and high concentrations of Inhaled nitric oxide reduces the minimum surfactant surface tension.

Almitrine as a non ventilatory strategy to improve intrapulmonary shunt in COVID-19 patients

In severe COVID-19 pulmonary failure, hypoxia is mainly related to pulmonary vasodilation with altered hypoxic pulmonary vasoconstriction (HPV). Besides prone positioning, other non-ventilatory strategies may reduce the intrapulmonary shunt. This study has investigated almitrine, a pharmacological option to improve oxygenation. Patients and Method. A case control series of 17 confirmed COVID-19 mechanically ventilated patients in prone or supine positioning was collected: 10 patients received two doses of almitrine (4 and 12 mcg/kg/min) at 30-45 min interval each, and were compared to 7 control COVID-matched patients conventionally treated. The end-point was the reduction of intra-pulmonary shunt increasing the PaO2 and ScvO2. Results Patients were male (59%) with median (25th, 75th percentiles) age of 70 (54-78) years and a BMI of 29 (23-34). At stable mechanical ventilatory settings, PaO2 (mmHg) at FiO2 1 (135 (85, 195) to 214 (121, 275); p = 0.06) tended to increase with almitrine. This difference was significant when the best PaO2 between the 2 doses was used : 215 (123,294) vs baseline (p = 0.01). A concomitant increase in ScvO2 occurred ((73 (72, 76) to 82 (80, 87); p = 0.02). Eight over 10 almitrine-treated patients increased their PaO2, with no clear dose-effect. During the same time, the controls did not change PaO2. In conclusion, in early COVID-19 with severe hypoxemia, almitrine infusion is associated with improved oxygenation in prone or supine positioning. This pharmacological intervention may offer an alternative and/or an additional effect to proning and might delay or avoid more demanding modalities such as ECMO.