Efficacy of nitroglycerin inhalation in reducing pulmonary arterial hypertension in children with congenital heart disease

Advances in the potential of nebulized inhalation for the treatment of pulmonary arterial hypertension

Pulmonary hypertension is a pathophysiologic manifestation of a heterogeneous group of diseases, with the main pathophysiologic mechanisms being persistent pulmonary vasoconstriction and irreversible vascular remodeling. The impact significantly affects the prognosis of patients with pulmonary hypertension. If it is not treated and intervened in time, it may lead to right ventricular failure and further endanger the patient's life. Within the past decade or so, nebulized inhalation therapy is considered to have advantages in the treatment of pulmonary hypertension as a safe, limited, and rapid therapy, for example, inhaled vasodilators (prostate analogs, nitroglycerin, carbon monoxide analogs sildenafil, and nitroprusside), inhaled anti-inflammatory and antiproliferative agents (simvastatin, and selatinib), and inhaled peroxides (levocetirizine) have been recognized as emerging therapeutic approaches in the treatment of pulmonary hypertension as emerging therapeutic approaches. Therefore, this article provides a brief review of recent advances in the potential of nebulized inhaled vasodilators, anti-inflammatory and antiproliferative agents, and anti-peroxides for the treatment of pulmonary hypertension, with the aim of providing different therapeutic options for the treatment of pulmonary hypertension, enhancing the quality of survival, alleviating symptoms, and improving the prognosis of patients with this condition.

Inhaled Nitroglycerin for Pulmonary Edema in Air Medical Services: A Retrospective Pilot Study

OBJECTIVE

The use of traditional inhaled pulmonary vasodilators, such as nitric oxide, to treat symptomatic pulmonary edema is not practical in the air medical or prehospital environment because of difficulty with administration. A hospital-based critical care air medical transport service initiated a pilot study to investigate the use of inhaled nitroglycerin (iNTG) as an alternative pulmonary vasodilator.

METHODS

For this pilot study, iNTG was administered using a jet nebulizer setup and concentrated nitroglycerin, both of which are widely available in acute care settings. In conjunction with medical oversight, transport personnel identified patients with respiratory distress secondary to pulmonary edema. Twenty-two months after initiating the protocol, a retrospective chart review was conducted. Data for patients receiving iNTG were retrospectively abstracted through a medical record search and manual chart review.

RESULTS

Twelve patients received iNTG during the pilot study. Basic demographics, medical comorbidities, concurrent medications, laboratory values, and radiographic studies were collected for each patient. Basic statistics were performed to identify any potential trends.

CONCLUSION

The administration of iNTG is feasible in an air medical transport setting and may provide a useful adjunct to treating patients with pulmonary edema and respiratory distress. Because iNTG delivery targets the pulmonary vasculature, this may be of particular benefit in patients with a poor hemodynamic profile. Larger randomized controlled or cohort studies are needed to specifically analyze and compare hemodynamics, diagnostics, and patient outcomes.

Nitroglycerin inhalation for acute treatment of pulmonary arterial hypertension in children with congenital heart disease

OBJECTIVES

Acute pulmonary hypertension and pulmonary hypertensive crisis may result in adverse clinical outcomes if unsuccessfully treated. Inhaled nitric oxide has long been considered as the standard pharmacotherapy for acute pulmonary hypertension, but lack of feasibility in some settings and evidences challenging its benefits lead to the use of alternative treatment, amongst which is nitroglycerin inhalation. The purpose of this review article is to discuss available data on the use of nitroglycerin inhalation for acute treatment of pulmonary hypertension in children with CHD and its potential benefit in post-operative setting.

DATA SOURCES

Literatures included in this review were acquired by searching in PubMed online database. Keywords used were "Pulmonary Hypertension", "Congenital heart defects", "Pediatrics", "Inhaled nitroglycerin", and its synonyms.

STUDY SELECTION

Title and abstract were screened to select relevant literatures including the three paediatric clinical trials on nitroglycerin inhalation. Critical appraisal of the clinical trials was then done using the University of Oxford Centre of Evidence-Based Medicine Critical Appraisal Tools.

CONCLUSIONS

Paediatric studies showed the benefit of nitroglycerin inhalation in uncorrected cases of CHD during catheterisation procedures. Until recently, there have been no studies conducted in paediatric post-operative CHD cases. Further study is required to provide evidence for inhaled nitroglycerin use in this setting including the appropriate dosing and potential side effects with repeated administration.

Nebulized Nitroglycerin for Coronavirus Disease 2019-Associated Acute Respiratory Distress Syndrome: A Case Report

We present a case where nitroglycerin tablets dissolved in saline and intravenous nitroglycerin solution were nebulized as surrogates for inhaled nitric oxide (iNO) after our iNO supply was depleted during the coronavirus disease 2019 (COVID-19) surge in New York. We gave this treatment to a COVID-19 patient with severe acute respiratory distress syndrome (ARDS) and hypercarbia. In response, the patient had immediate and clinically meaningful improvement in multiple organ systems despite no other interventions or ventilator changes.

The Regulation of Pulmonary Vascular Tone by Neuropeptides and the Implications for Pulmonary Hypertension

Pulmonary hypertension (PH) is an incurable, chronic disease of small pulmonary vessels. Progressive remodeling of the pulmonary vasculature results in increased pulmonary vascular resistance (PVR). This causes secondary right heart failure. PVR is tightly regulated by a range of pulmonary vasodilators and constrictors. Endothelium-derived substances form the basis of most current PH treatments. This is particularly the case for pulmonary arterial hypertension. The major limitation of current treatments is their inability to reverse morphological changes. Thus, there is an unmet need for novel therapies to reduce the morbidity and mortality in PH. Microvessels in the lungs are highly innervated by sensory C fibers. Substance P and calcitonin gene-related peptide (CGRP) are released from C-fiber nerve endings. These neuropeptides can directly regulate vascular tone. Substance P tends to act as a vasoconstrictor in the pulmonary circulation and it increases in the lungs during experimental PH. The receptor for substance P, neurokinin 1 (NK1R), mediates increased pulmonary pressure. Deactivation of NK1R with antagonists, or depletion of substance P prevents PH development. CGRP is a potent pulmonary vasodilator. CGRP receptor antagonists cause elevated pulmonary pressure. Thus, the balance of these peptides is crucial within the pulmonary circulation (Graphical Abstract). Limited progress has been made in understanding their impact on pulmonary pathophysiology. This is an intriguing area of investigation to pursue. It may lead to promising new candidate therapies to combat this fatal disease. This review provides a summary of the current knowledge in this area. It also explores possible future directions for neuropeptides in PH.

Intravenous anesthesia with nitroglycerin inhalation for surgical abortion in a patient with severe congenital heart disease and low oxygen saturation: A case report

INTRODUCTION

Congenital heart disease and pulmonary arterial hypertension are perilous to a gravida for the high morbidity and mortality.

CASE PRESENTATION

We report an extremely rare case of a 27-year-old gravida with congenital heart disease and severe pulmonary arterial hypertension of 115 mmHg. Arterial blood gas analysis revealed her oxygen saturation (SpO2) of 67.8% and oxygen partial pressure of 40.0 mmHg, which were severely low. The patient was diagnosed as having gestation combined with congenital heart disease, severe pulmonary arterial hypertension, and hypoxemia.

INTERVENTIONS

The patient was treated with surgical abortion. The patient was monitored with invasive blood pressure (BP), electrocardiogram (ECG), heart rate, SpO2, and arterial gas analysis as from entry into the operation suite. We performed total intravenous anesthesia with nitroglycerin inhalation. She was returned to the ward at the end of surgery.

CONCLUSION

To our knowledge, this is the first reported case in a gravida with severe heart disease and very low SpO2. Nitroglycerin inhalation may provide dilation of the pulmonary artery, reduction of pulmonary artery pressure, and improvement of oxygenation. Our case report may provide alternative regimen to anesthesia practitioners in similar circumstances.

Inhaled therapy for the management of perioperative pulmonary hypertension

Patients with pulmonary hypertension (PH) are at high risk for complications in the perioperative setting and often receive vasodilators to control elevated pulmonary artery pressure (PAP). Administration of vasodilators via inhalation is an effective strategy for reducing PAP while avoiding systemic side effects, chiefly hypotension. The prototypical inhaled pulmonary-specific vasodilator, nitric oxide (NO), has a proven track record but is expensive and cumbersome to implement. Alternatives to NO, including prostanoids (such as epoprostenol, iloprost, and treprostinil), NO-donating drugs (sodium nitroprusside, nitroglycerin, and nitrite), and phosphodiesterase inhibitors (milrinone, sildenafil) may be given via inhalation for the purpose of treating elevated PAP. This review will focus on the perioperative therapy of PH using inhaled vasodilators.

Pharmacologic management of perioperative pulmonary hypertension

Perioperative pulmonary hypertension can originate from an established disease or acutely develop within the surgical setting. Patients with increased pulmonary vascular resistance are consequently at greater risk for complications. Despite the various specific therapies available, the ideal therapeutic approach in this patient population is not currently clear. This article describes the basic principles of perioperative pulmonary hypertension and reviews the different classes of agents used to promote pulmonary vasodilation in the surgical setting.

Changes in pulmonary hemodynamics induced by experimental myocardial ischemia in nitroglycerin- or acetylcholine-treated rabbits

The responses of cardiovascular parameters to left-ventricular myocardial ischemia induced under control conditions and after administration of nitroglycerin or acetylcholine were examined in rabbits. In nitroglycerine-treated rabbits, experimental myocardial ischemia produced less pronounced depressor BP shifts in the pulmonary artery than those produced by ischemia in controls (prior to pharmacological treatment) or by experimental ischemia provoked after acetylcholine infusion. Control and experimental ischemia (provoked after nitroglycerin or acetylcholine administration) induced the same drop in pulmonary blood fl ow accompanied with insignificant changes in vascular pulmonary resistance. Experimental ischemia produced smaller pressure increase in left atrium of nitroglycerine-treated rabbits (evidencing a smaller drop in left ventricular contractility) than the control ischemia performed prior to pharmacological treatment, or the experimental ischemia in acetylcholine-treated rabbits, which attested to protective effect of nitroglycerin against ischemia.

Saudi Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: Perioperative management in patients with pulmonary hypertension

Patients with pulmonary hypertension (PH) are being encountered more commonly in the perioperative period and this trend is likely to increase as improvements in the recognition, management, and treatment of the disease continue to occur. Management of these patients is challenging due to their tenuous hemodynamic status. Recent advances in the understanding of the patho-physiology, risk factors, monitoring, and treatment of the disease provide an opportunity to reduce the morbidity and mortality associated with PH in the peri-operative period. Management of these patients requires a multi-disciplinary approach and meticulous care that is best provided in centers with vast experience in PH.

In this review, we provide a detailed discussion about oerioperative strategies in PH patients, and give evidence-based recommendations, when applicable.

Synthesis, nitric oxide release, and α-glucosidase inhibition of nitric oxide donating apigenin and chrysin derivatives

α-Glucosidase (AG) play crucial roles in the digestion of carbohydrates. Inhibitors of α-glucosidase (AGIs) are promising candidates for the development of anti-diabetic drugs. Here, five series of apigenin and chrysin nitric oxide (NO)-donating derivatives were synthesised and evaluated for their AG inhibitory activity and NO releasing capacity in vitro. Except for 9a-c, twelve compounds showed remarkable inhibitory activity against α-glucosidase, with potency being better than that of acarbose and 1-deoxynojirimycin. All organic nitrate derivatives released low concentrations of NO in the presence of l-cysteine. Structure activity relationship studies indicated that 5-OH, hydrophobic coupling chain, and carbonyl groups of the coupling chain could enhance the inhibitory activity. Apigenin and chrysin derivatives therefore represents a new class of promising compounds that can inhibit α-glucosidase activity and supply moderate NO for preventing the development of diabetic complications.

Can nitric oxide-based therapy prevent bronchopulmonary dysplasia?

A growing understanding of endogenous nitric oxide (NO) biology is helping to explain how and when exogenous NO may confer benefit or harm; this knowledge is also helping to identify new better-targeted NO-based therapies. In this review, results of the bronchopulmonary dysplasia clinical trials that used inhaled NO in the preterm population are placed in context, the biologic basis for novel NO therapeutics is considered, and possible future directions for NO-focused clinical and basic research in developmental lung disease are identified.

A comparison of organic and inorganic nitrates/nitrites

Although both organic and inorganic nitrates/nitrites mediate their principal effects via nitric oxide, there are many important differences. Inorganic nitrate and nitrite have simple ionic structures and are produced endogenously and are present in the diet, whereas their organic counterparts are far more complex, and, with the exception of ethyl nitrite, are all medicinally synthesised products. These chemical differences underlie the differences in pharmacokinetic properties allowing for different modalities of administration, particularly of organic nitrates, due to the differences in their bioavailability and metabolic profiles. Whilst the enterosalivary circulation is a key pathway for orally ingested inorganic nitrate, preventing an abrupt effect or toxic levels of nitrite and prolonging the effects, this is not used by organic nitrates. The pharmacodynamic differences are even greater; while organic nitrates have potent acute effects causing vasodilation, inorganic nitrite's effects are more subtle and dependent on certain conditions. However, in chronic use, organic nitrates are considerably limited by the development of tolerance and endothelial dysfunction, whereas inorganic nitrate/nitrite may compensate for diminished endothelial function, and tolerance has not been reported. Also, while inorganic nitrate/nitrite has important cytoprotective effects against ischaemia-reperfusion injury, continuous use of organic nitrates may increase injury. While there are concerns that inorganic nitrate/nitrite may induce carcinogenesis, direct evidence of this in humans is lacking. While organic nitrates may continue to dominate the therapeutic arena, this may well change with the increasing recognition of their limitations, and ongoing discovery of beneficial effects and specific advantages of inorganic nitrate/nitrite.

New perspectives for the treatment of pulmonary hypertension

Pulmonary hypertension (PH) is a debilitating disease with a poor prognosis. Therapeutic options remain limited despite the introduction of prostacyclin analogues, endothelin receptor antagonists and phosphodiesterase 5 inhibitors within the last 15 years; these interventions address predominantly the endothelial and vascular dysfunctionS associated with the condition, but simply delay progression of the disease rather than offer a cure. In an attempt to improve efficacy, emerging approaches have focused on targeting the pro-proliferative phenotype that underpins the pulmonary vascular remodelling in the lung and contributes to the impaired circulation and right heart failure. Many novel targets have been investigated and validated in animal models of PH, including modulation of guanylate cyclases, phosphodiesterases, tyrosine kinases, Rho kinase, bone morphogenetic proteins signalling, 5-HT, peroxisome proliferator activator receptors and ion channels. In addition, there is hope that combinations of such treatments, harnessing and optimizing vasodilator and anti-proliferative properties, will provide a further, possibly synergistic, increase in efficacy; therapies directed at the right heart may also offer an additional benefit. This overview highlights current therapeutic options, promising new therapies, and provides the rationale for a combination approach to treat the disease.

Advances in diagnosis and treatment of pulmonary arterial hypertension in neonates and children with congenital heart disease

BACKGROUND

This article aims to review recent advances in the diagnosis and treatment of pulmonary arterial hypertension in neonates and children with congenital heart disease.

DATA SOURCES

Articles on pulmonary arterial hypertension in congenital heart disease were retrieved from PubMed and MEDLINE published after 1958.

RESULTS

A diagnosis of primary (or idiopathic) pulmonary arterial hypertension is made when no known risk factor is identified. Pulmonary arterial hypertension associated with congenital heart disease constitutes a heterogenous group of conditions and has been characterized by congenital systemic-to-pulmonary shunts. Despite the similarities in histologic appearance of pulmonary vascular disease, there are differences between pulmonary arterial hypertension secondary to congenital systemic-to-pulmonary shunts and those with other conditions with respect to pathophysiology, therapeutic strategies, and prognosis. Revision and subclassification within the category of secondary pulmonary arterial hypertension based on pathophysiology were conducted to improve specific treatments. The timing of surgical repair is crucial to prevent and minimize risk of postoperative pulmonary arterial hypertension. Drug therapies including prostacyclin, endothelin-receptor antagonist, phosphodiesterase inhibitor, and nitric oxide have been evolved with promising results in neonates and children.

CONCLUSIONS

Among the different forms of congenital heart diseases, an early correction generally prevents subsequent development of pulmonary arterial hypertension. Emerging therapies for treatment of patients with idiopathic pulmonary arterial hypertension also improve quality of life and survival in neonates and children with congenital heart disease associated with pulmonary arterial hypertension. Heart and lung transplantation or lung transplantation in combination with repair of the underlying cardiac defect is a therapeutic option in a minority of patients. Partial repair options are also beneficial in some selected cases. Randomized controlled trials are needed to evaluate the safety and efficacy of these therapies including survival and long-term outcome.

New biomaterials for the sustained release of nitric oxide: past, present and future

Nitric oxide (NO), the 1992 'Molecule of the Year', is the focus of immense medical and scientific exploration. Interest in NO has grown exponentially since the initial and relatively recent discovery that NO is the long sought after endothelial relaxing factor. There is intense research that is continuing to expose the extensive physiologic impact of NO in virtually all organ and tissue systems under both normal and pathological conditions. Both the rate of delivery and the amount of site-specific generated NO modulate a balance between cytoregulatory and cytotoxic activities. This balancing act and the very short lifetime of NO under physiological conditions pose an extreme challenge with respect to harnessing the exceptional therapeutic potential of this molecule. Over the past two decades, the race to translate the therapeutic potential of NO to the bedside has been overwhelmingly through the development of numerous NO delivery devices/vehicles. So far no one product has emerged as a clearcut winner. This review: discusses and evaluates NO-donating platforms that are available at present; attempts to enhance delivery and efficacy through encapsulation in silane-based hydrogel matrices; and discusses and evaluates the future direction of these advances.

Recent developments in nitric oxide donor drugs

During the 1980s, the free radical, nitric oxide (NO), was discovered to be a crucial signalling molecule, with wide-ranging functions in the cardiovascular, nervous and immune systems. Aside from providing a credible explanation for the actions of organic nitrates and sodium nitroprusside that have long been used in the treatment of angina and hypertensive crises respectively, the discovery generated great hopes for new NO-based treatments for a wide variety of ailments. Decades later, however, we are still awaiting novel licensed agents in this arena, despite an enormous research effort to this end. This review explores some of the most promising recent advances in NO donor drug development and addresses the challenges associated with NO as a therapeutic agent.