The use of oral sildenafil for management of right ventricular dysfunction after pediatric heart transplantation

Preoperative Sildenafil in Pediatric Patients Undergoing Congenital Heart Surgeries: A Systematic Review and Meta-Analysis

Background. Pulmonary hypertension (PH) is a common complication of congenital heart disease (CHD). With early surgical intervention, outcomes have improved over the last two decades. Persistent PH, however, may still occur following surgery. Sildenafil has been shown to be beneficial for postoperative pulmonary hypertensive crises. The role of preoperative sildenafil in controlling postoperative PH is poorly elucidated. This study aimed to evaluate the effect of preoperative sildenafil on pediatric patients undergoing congenital heart surgeries. Methods. A comprehensive literature search was conducted in scientific databases. We included randomized controlled trials which assessed the effect of preoperative sildenafil in pediatric patients with CHD undergoing repair surgeries. Primary outcomes were pre- and postoperative differences in mean pulmonary arterial pressure (mPAP) and mean pulmonary artery/aortic pressure ratio (PA/Ao ratio). Results. Four studies (n = 233) were retained for the final analysis. Dose of sildenafil ranged from .3 to .5 mg/kg every 4-6 hours via oral/nasogastric route, with timing of administration varied from 1 to 2 weeks before surgery. Compared to controls, preoperative sildenafil was associated with greater reduction in postoperative mPAP (MD -5.02; 95% CI [-8.91, -1.13]) and mean PA/Ao ratio (MD -.11; 95% CI [-.17, -.06]). Shorter CPB time, ICU length of stay, and duration of mechanical ventilation were also observed in the sildenafil group. Conclusion. Preoperative sildenafil is beneficial in reducing PAP, thereby reducing the risk of postoperative PH crisis. Further studies are warranted to identify the optimal dosage and timing of administration of sildenafil in CHD patients prior to surgery.

Pediatric Pulmonary Hypertension: Definitions, Mechanisms, Diagnosis, and Treatment

Pediatric pulmonary hypertension (PPH) is a multifactorial disease with diverse etiologies and presenting features. Pulmonary hypertension (PH), defined as elevated pulmonary artery pressure, is the presenting feature for several pulmonary vascular diseases. It is often a hidden component of other lung diseases, such as cystic fibrosis and bronchopulmonary dysplasia. Alterations in lung development and genetic conditions are an important contributor to pediatric pulmonary hypertensive disease, which is a distinct entity from adult PH. Many of the causes of pediatric PH have prenatal onset with altered lung development due to maternal and fetal conditions. Since lung growth is altered in several conditions that lead to PPH, therapy for PPH includes both pulmonary vasodilators and strategies to restore lung growth. These strategies include optimal alveolar recruitment, maintaining physiologic blood gas tension, nutritional support, and addressing contributing factors, such as airway disease and gastroesophageal reflux. The outcome for infants and children with PH is highly variable and largely dependent on the underlying cause. The best outcomes are for neonates with persistent pulmonary hypertension (PPHN) and reversible lung diseases, while some genetic conditions such as alveolar capillary dysplasia are lethal. © 2021 American Physiological Society. Compr Physiol 11:2135-2190, 2021.

Initial experience with bosentan for the management of pulmonary hypertension after heart transplantation

BACKGROUND

Pulmonary hypertension (PH) after heart transplantation (HT) is associated to right ventricular (RV) dysfunction and increased morbidity and mortality. We present our experience with bosentan for the treatment of PH after HT.

METHODS

A retrospective evaluation of patients with PH receiving bosentan post-transplant was performed. Pulmonary hemodynamics before and after bosentan (BG) and clinical outcomes were assessed and compared to a historical control group (CG) not receiving bosentan.

RESULTS

Between 2013 and 2016, 21 patients were treated post-transplant with bosentan. Twenty-four hours after bosentan initiation, there were significant decreases in systolic (42.5 ± 8 to 38.1 ± 8 mm Hg, P = 0.015), diastolic (21.4 ± 4 to 17.8 ± 6 mm Hg, P = 0.008) and mean (29.6 ± 5 to 25 ± 6 mm Hg, P = 0.001) pulmonary artery pressures (PAP), transpulmonary gradient (13.1 ± 3 to 9.7 ± 4 mm Hg, P < 0.001), diastolic gradient (5.2 ± 4 to 2.3 ± 3 mm Hg, P = 0.001) and pulmonary vascular resistance (PVR) (2.2 ± 1 to 1.6 ± 1WU, P = 0.015). This effect was maintained at day 3. Compared with CG, BG showed significantly more decrease in PVR (0.7 ± 0.9 vs 0.3 ± 1.7WU, P = 0.025) and mean PAP (4.6 ± 5.2 vs 1.5 ± 4.4 mm Hg, P = 0.040). RV function 7 days post-transplant was significantly better in BG compared to CG, P = 0.004. There were not clinically significant interactions between bosentan and immunosuppressive treatment.

CONCLUSIONS

Bosentan, initiated early post-transplant, was associated with a significant decrease in PVR. Bosentan was well tolerated and did not interact with immunosuppressive treatment.

Hospital and intensive care unit management of decompensated pulmonary hypertension and right ventricular failure

Pulmonary hypertension and concomitant right ventricular failure present a diagnostic and therapeutic challenge in the intensive care unit and have been associated with a high mortality. Significant co-morbidities and hemodynamic instability are often present, and routine critical care unit resuscitation may worsen hemodynamics and limit the chances of survival in patients with an already underlying poor prognosis. Right ventricular failure results from structural or functional processes that limit the right ventricle’s ability to maintain adequate cardiac output. It is commonly seen as the result of left heart failure, acute pulmonary embolism, progression or decompensation of pulmonary hypertension, sepsis, acute lung injury, or in the perioperative setting. Prompt recognition of the underlying cause and institution of treatment with a thorough understanding of the elements necessary to optimize preload, cardiac contractility, enhance systemic arterial perfusion, and reduce right ventricular afterload are of paramount importance. Moreover, the emergence of previously uncommon entities in patients with pulmonary hypertension (pregnancy, sepsis, liver disease, etc.) and the availability of modern devices to provide support pose additional challenges that must be addressed with an in-depth knowledge of this disease.

Sildenafil in Infants and Children

Pulmonary arterial hypertension (PAH) management has been transformed in recent times with the advent of cheap and effective diagnostic tools and therapy. Sildenafil, a phosphodiesterase-V inhibitor, has been at the centre of this treatment, and its success in treating PAH has led to its widespread uptake in adult and paediatric pulmonary hypertension (PH), as a first line treatment choice. This might apply to persistent pulmonary hypertension of the newborn (PPHN) or bronchopulmonary dysplasia, as well as to more complex diseases, such as idiopathic pulmonary hypertension. Although recent data regarding long-term mortality and the repeal of Food and Drug Administration (FDA) approval has complicated the issue, Sildenafil continues to be the major treatment option for paediatric PH for patients in a variety of contexts, and this does not seem likely to change in the foreseeable future. In this review, we provide a summary of pulmonary hypertension in infants and children and the use of Sildenafil for such diseases.

Low-Dose Donor Dopamine Is Associated With a Decreased Risk of Right Heart Failure in Pediatric Heart Transplant Recipients

BACKGROUND

Previous studies in adults have suggested that donor dopamine treatment may improve recipient outcomes in organ transplantation; in this analysis, we aimed to determine if donor dopamine reduces the incidence of postoperative right heart failure (RHF) in pediatric heart transplant recipients.

METHODS

Data for recipients aged 18 years or younger transplanted at our institution between January 1, 2000, and June 15, 2011, and their respective donors were obtained. The presence of postoperative RHF was assessed for in all subjects. Donor dopamine dose was stratified into 3 groups: none, low-dose (≤5 μg/kg per minute), and high-dose (>5 μg/kg per minute). Logistic regression was used to assess the relationship between donor dopamine dose and recipient RHF.

RESULTS

Of 192 recipients, 34 (18%) experienced postoperative RHF. There was no difference in baseline demographics between recipients with and without RHF. When controlling for pulmonary vascular resistance index, graft ischemic time, and cardiopulmonary bypass time, donor low-dose dopamine was independently associated with a decreased risk of RHF (odds ratio, 0.16; 95% confidence interval, 0.04-0.70; P = 0.02); however high-dose dopamine was neither associated with, nor protective of, RHF (odds ratio, 0.31; 95% confidence interval, 0.06-1.6; P = 0.16).

CONCLUSIONS

Despite advances in perioperative care of the recipient, RHF persists as a complication of pediatric heart transplantation. In this study, donor pretreatment with low-dose dopamine is associated with a decreased risk of postoperative RHF in pediatric heart recipients. Further studies into this association may be useful in determining the utility of empiric donor pretreatment with low-dose dopamine.

Sildenafil in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a life-threatening disease of varied etiologies. Although PAH has no curative treatment, a greater understanding of pathophysiology, technological advances resulting in early diagnosis, and the availability of several newer drugs have improved the outlook for patients with PAH. Sildenafil is one of the therapeutic agents used extensively in the treatment of PAH in children, as an off-label drug. In 2012, the United States Food and Drug Administration (USFDA) issued a warning regarding the of use high-dose sildenafil in children with PAH. This has led to a peculiar situation where there is a paucity of approved therapies for the management of PAH in children and the use of the most extensively used drug being discouraged by the regulator. This article provides a review of the use of sildenafil in the treatment of PAH in children.