The Assessment of Right Ventricular Contractility in Response to Sildenafil
The primary objective of this study is to examine the effects of Sildenafil, administered during cardiac catheterization, on right ventricular contractility in children with pulmonary arterial hypertension.
|Study Design:||Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||The Assessment of Right Ventricular Contractility in Response to Sildenafil in Pediatric Patients With Pulmonary Arterial Hypertension|
- Increase (% change) in endsystolic elastance of the right ventricle from baseline (in comparison to change in endsystolic elastance after inhaled NO) [ Time Frame: 30 mins after Sildenafil adminsitration ] [ Designated as safety issue: Yes ]
|Study Start Date:||August 2008|
|Estimated Primary Completion Date:||June 2014 (Final data collection date for primary outcome measure)|
One oral dose of Sildenafil (0.5 mg/kg) will be administered nia a nasogastric tube
Other Name: Viagra
The effectiveness of Sildenafil as a pulmonary vasodilator in children with heart disease was first reported in detail during cardiac catheterization and postoperatively in 2003. It is now used frequently for long-term treatment of children with pulmonary arterial hypertension at The Hospital for Sick Children and it is now a routine part of the hospital's testing protocol for all patients being evaluated for pulmonary hypertension in the cardiac catheterization laboratory.
The beneficial effects of Sildenafil in pulmonary hypertension are thought to result predominantly from relative vasodilatory and antiproliferative effects on the pulmonary vasculature. On the basis of early data showing lack of significant PDE5 expression in the normal heart, PDE5 was thought to be expressed in the coronary vessels but not in the human myocardium. Very recently, it was reported for the first time that PDE5 is markedly upregulated in hypertrophied right ventricular myocardium in humans and that in the rat PDE5 inhibition with Sildenafil increases contractility in hypertrophied right ventricular myocardium but not in normal right ventricle, which lacks PDE5 expression. The assessment of right ventricular contractility in humans is a challenge, but we have developed several techniques that are recognized as 'state of the art' assessment of right ventricular function.
The purpose of this study is to examine the effects of Sildenafil, which is routinely administered during cardiac catheterization to assess pulmonary vascular resistance, on right ventricular contractility in children with pulmonary arterial hypertension.
|The Hospital for Sick Children|
|Toronto, Ontario, Canada|
|Principal Investigator:||Andrew Redington, MD||The Hospital for Sick Children|