Currently, there are an estimated 300-600 adults living in Switzerland with congenital heart disease (CHD) and a right ventricle (RV) in subaortic (systemic) position. This includes adults with prior atrial switch operations for complete transposition of the great arteries (D-TGA) and adults with congenitally corrected transposition of the great arteries (ccTGA). Although midterm survival is favourable, late outcome is compromised by ventricular dysfunction of the systemic RV, end-stage heart failure, and premature death. Medical heart failure therapy (ACE-inhibitors, beta-blockers, aldosterone antagonists) has been shown to improve ventricular function and survival in patients with left heart failure from acquired heart disease. Unfortunately, case-reports and studies failed to show similar clinical benefits of these drugs in adults with a failing systemic RV. Currently, the only established end-stage therapy for a failing systemic RV is heart transplantation. Given the ubiquitous shortage of donor organs and the number of adults at risk, medical options to improve the fate of patients with a systemic RV are urgently needed.~The RV and left ventricle (LV) have different embryological origins, myocardial architecture and contractile properties. In response to increased afterload, as in an RV in systemic position, the RV expresses a fetal gene pattern, with an increase in phosphodiesterase (PDE)-5 expression. PDE-5 is not expressed in the normal RV, but is up-regulated in the hypertrophied RV. PDE-5 inhibition increases contractility in experimental models of RV hypertrophy, but not in the normal RV. In clinical practice, the effects of PDE-5 inhibition on systemic RV function and exercise capacity in adults with TGA have not been tested.~This study assesses in a double-blind, randomized, placebo-controlled multi-center pilot trial the effect of PDE-5 inhibition with Tadalafil on RV size and function, exercise capacity and neurohumoral activation in adults with a systemic RV over a 3-year follow-up period.
This study assesses in a double-blind, randomized, placebo-controlled multi-center pilot trial the effect of PDE-5 inhibition with Tadalafil on right ventricle size and function, exercise capacity and neurohumoral activation in adults with congenital heart disease and a right ventricle in subaortic position over a 3-year follow-up period.