Clinical challenges late after correction of tetralogy of Fallot

This thesis focused on several clinical challenges which may occur late after surgical correction of tetralogy of Fallot. Among several other topics, three important clinical challenges were studied: (1) timing of pulmonary valve replacement, (2) risk stratification, (3) prevention and treatment of right ventricular heart failure. These topics are considered to be controversial and are relevant to the care of most adult patients. Most of the research described in this thesis was performed by collaboration with several other Dutch and international centers.
We found that lower preoperative right ventricular volumes were associated with favorable mid-to-late hemodynamic outcomes after pulmonary valve replacement. However, results from a propensity-adjusted international cohort suggested that pulmonary valve replacement may be postponed in asymptomatic patients until conservative criteria of chapter 12 are met.
Our research on risk stratification revealed that QRS fragmentation was superior to QRS duration in predicting mortality and that cardiovascular magnetic resonance imaging had additional value compared to a well-established noninvasive risk model. Therefore, QRS fragmentation and cardiovascular magnetic resonance imaging should be added to current risk stratification models.
We performed a randomized controlled clinical trial (chapter 15) to study the effects of the angiotensin receptor blocker losartan on right ventricular dysfunction in tetralogy of Fallot. In this trial, losartan had no significant effect on right ventricular dysfunction or secondary outcome parameters. Our results suggest that losartan should not be prescribed routinely in asymptomatic patients. Future larger studies may determine whether there might be a role for losartan in specific vulnerable subgroups.