Evaluation of the Tolerability of Intermittent Intravenous Sildenafil in Pediatric Patients With Pulmonary Hypertension

Continuous and intermittent administration of intravenous sildenafil in critically ill infants with pulmonary hypertension

Intravenous (IV) sildenafil may be administered as a continuous infusion or intermittent bolus dosing in infants with pulmonary hypertension (PH). We aimed to compare these delivery methods.

METHODS

We retrospectively evaluated subjects less than 12 months old treated with IV sildenafil for PH. Vital signs, oxygen requirement, vasoactive-inotropic score (VIS), and echocardiogram results before and after sildenafil initiation, and the need for discontinuation due to side effects, were noted.

RESULTS

Forty-three subjects were identified (23 continuous, 20 intermittent). There were clinically significant differences in PH classifications between groups. The continuous group was significantly younger (p = 0.010) with higher baseline severity of illness suggested by higher inspired oxygen (FiO₂ ) and VIS (p = 0.012). After sildenafil initiation, there were no significant differences in changes in blood pressure, oxygen saturation, FiO₂ , or VIS between groups, and no difference in the number of subjects requiring discontinuation due to side effects (4 continuous, 1 intermittent, p = 0.351). Eight continuous group subjects (34.8%) and 3 intermittent group subjects (15.0%) died (p = 0.024), but echocardiographic improvement in PH degree was more common in the continuous group (77.8% vs. 33.3%, p = 0.007).

CONCLUSION

In this small cohort of infants treated with continuous or intermittent IV sildenafil, in the setting of different baseline characteristics between groups, there were no significant differences in changes in vital signs, VIS, FiO₂ , or need for discontinuation of therapy due to side effects. Higher continuous group mortality may be explained by greater baseline illness severity, but larger prospective, randomized studies are required to investigate these different delivery methods.

Treatment of pediatric pulmonary arterial hypertension: A focus on the NO-sGC-cGMP pathway

OBJECTIVE

While pulmonary arterial hypertension (PAH) is rare in infants and children, it results in substantial morbidity and mortality. In recent years, prognosis has improved, coinciding with the introduction of new PAH-targeted therapies, although much of their use in children is off-label. Evidence to guide the treatment of children with PAH is less extensive than for adults. The goal of this review is to discuss the treatment recommendations for children with PAH, as well as the evidence supporting the use of prostanoids, endothelin receptor antagonists (ERAs), and phosphodiesterase type 5 inhibitors (PDE5i) in this setting.

DATA SOURCES

Nonsystematic PubMed literature search and authors' expertise.

STUDY SELECTION

Articles were selected concentrating on the nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway in PAH. The methodology of an ongoing study evaluating the sGC stimulator riociguat in children with PAH is also described.

RESULTS

Despite recent medical advances, improved therapeutic strategies for pediatric PAH are needed. The efficacy and tolerability of riociguat in adults with PAH have been well trialed.

CONCLUSION

The pooling of data across trials, supplemented by registry data, will help to confirm the safety and tolerability of prostanoids, ERAs, and PDE5i in children. Ongoing studies will clarify the place of sGC stimulators in the treatment strategy for pediatric PAH.

Role of microRNA-130a in the pathogeneses of obstructive sleep apnea hypopnea syndrome-associated pulmonary hypertension by targeting the GAX gene

OBJECTIVE

The purpose of this study was to elucidate the role of microRNA-130a (miR-130a) in obstructive sleep apnea hypopnea syndrome (OSAHS)-associated pulmonary hypertension (PHT) by targeting the growth arrest-specific homeobox (GAX) gene.

METHODS

A total of 108 patients with OSAHS-associated PHT were recruited as the OSAHS-associated PHT group and 110 healthy individuals were randomly selected as the normal control group. Human umbilical vein endothelial cells (HUVECs) were selected and divided into the control, miR-130a mimic, mimic negative control (NC), miR-130a inhibitor, and inhibitor-NC groups. The dual luciferase reporter gene assay was used to identify the relationship between miR-130a and the GAX gene. The quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were applied for the relative expressions of miR-130a and the mRNA and protein expressions of GAX. Serum levels of endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), nitric oxide (NO), and super oxide dismutase (SOD) were detected. Cell apoptosis and angiogenic activity were analyzed by flow cytometry and cell tube formation assay.

RESULTS

GAX was a target gene of miR-130a. Compared with the normal control group, the relative expression of miR-130a and the serum levels of ET-1 and VEGF were increased, whereas the mRNA expression of GAX and the serum levels of NO and SOD were decreased in the OSAHS-associated PHT group. Compared with the control, mimic-NC, and inhibitor-NC groups, the relative expressions of miR-130a in the miR-130a mimic group were enhanced, whereas the expression of miR-130a in the miR-130a inhibitor group was reduced. However, the mRNA and protein expressions of GAX showed an opposite trend in the miR-130a mimic and miR-130a inhibitor groups. In comparison to the control, mimic-NC, and inhibitor-NC groups, the miR-130a mimic group had an increase of ET-1 and VEGF expressions, whereas the expressions of NO and SOD were reduced. However, the miR-130a inhibitor group exhibited an opposite trend. The apoptosis rate and tube formation number in the miR-130a mimic group were obviously increased, whereas the miR-130a inhibitor group showed an obvious decrease.

CONCLUSION

These data provided strong evidence that miR-130a may be involved in the progression of OSAHS-associated PHT by down-regulating GAX gene.