Sildenafil therapy for neonatal and childhood pulmonary hypertensive vascular disease.
OBJECTIVE
We hypothesised that sildenafil would improve hemodynamics in children with pulmonary hypertension and attenuate rebound pulmonary hypertension after inhaled nitric oxide withdrawal.


METHODS
We undertook an open-label, single-drug study of sildenafil in patients under 5 years of age with either symptomatic or rebound pulmonary hypertension following inhaled nitric oxide withdrawal.


RESULTS
We recruited 25 patients (median age 180 days, 10-1790) to receive sildenafil. The median right ventricular to systemic systolic blood pressure ratio before sildenafil therapy was 1.0 (0.5-1.4) and decreased to 0.5 (with a range from 0.3 to 1.3; p = 0.0002). In five patients the baseline pulmonary vascular resistance index was 10 (7.1-13.6) Wood units metre square and decreased to 5.8 (2.7-15.6) Wood units metre square (p = 0.04) at 6 months. Ten patients were treated with sildenafil for a median of 34 days (9-499) until resolution of pulmonary artery hypertension and continue to do well. Six patients continued sildenafil therapy for a median of 1002 days (384-1574) with improvement but without resolution of pulmonary hypertension. There was no change in serum creatinine, urea, liver function tests, or platelet count. In 15 patients sildenafil abolished rebound pulmonary artery hypertension following withdrawal of inhaled nitric oxide. Median right ventricular pressure to systemic systolic pressure ratio decreased from 1.0 (0.8-1.4) during nitric oxide withdrawal to 0.4 (0.3-0.8) p = 0.006 after pre-treatment with sildenafil.


CONCLUSIONS
In children under 5 years of age with severe pulmonary hypertension, sildenafil therapy resulted in prolonged hemodynamic improvements without adverse effects. Sildenafil attenuated rebound pulmonary hypertension after withdrawal of inhaled nitric oxide.
Hospital for Sick Children, University of Toronto, Canada.
Tilman
T
Humpl
Janette T
JT
Reyes
Simon
S
Erickson
Ruth
R
Armano
Helen
H
Holtby
Ian
I
Adatia
D000284:Administration, Oral; D006328:Cardiac Catheterization; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D058986:Phosphodiesterase 5 Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D010879:Piperazines / Q000008:administration & dosage / Q000627:therapeutic use*; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D011687:Purines / Q000008:administration & dosage / Q000627:therapeutic use; D012189:Retrospective Studies; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome; D016278:Ventricular Function, Right / Q000187:drug effects; D017725:Ventricular Pressure / Q000187:drug effects
D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate