Restrictive right ventricular performance assessed by cardiac magnetic resonance after balloon valvuloplasty of critical pulmonary valve stenosis

Background: Little data are published about right ventricular diastolic performance in patients with critical pulmonary valve stenosis after balloon pulmonary valvuloplasty thus far. Methods: A total of 44 patients with isolated critical pulmonary valve stenosis who had undergone balloon valvuloplasty with haemodynamic recordings were enrolled to the study; 33 patients who came for follow-up underwent further imaging by echocardiography after 6 months and their right ventricular functional parameters were compared with 33 control patients of the same age and sex. Out of 33 patients, 21 underwent cardiac MRI with late gadolinium enhancement to assess the presence of right ventricular fibrosis. Results: The right ventricular systolic pressure (p < 0.0001) and right ventricular outflow tract gradient (p < 0.0001) decreased acutely (p < 0.0001) after balloon valvuloplasty. During follow-up, M-mode left ventricular end diastolic dimension (p < 0.001) and end systolic dimension increased (p < 0.001), whereas right ventricular end diastolic dimension decreased (p < 0.001). Compared with controls, patients (n = 33) had significantly reduced tricuspid annular E-a and higher E/E-a (p < 0.001). Right ventricular systolic dysfunction was also suggested by reduced tricuspid annular systolic velocity (p < 0.001). Late gadolinium enhancement was demonstrated in 13 out of 21 patients with restrictive physiology, which involves the anterior right ventricular outflow tract, anterior wall, and inferior wall. The right ventricular late gadolinium enhancement score correlated positively with age (r = 0.7, p < 0.001) and right ventricular mass index (r = 0.52, p < 0.001). Conclusion: The persistence of right ventricular diastolic dysfunction after relief of chronic pressure overload of critical pulmonary valve stenosis suggests that a factor - other than increase in afterload - is involved in this physiology. Fibrosis is the most likely factor responsible for persistence of restrictive physiology as documented by late gadolinium enhancement.