Stroke Volume Ratio Predicts Redilatation of the Right Ventricle After Pulmonary Valve Replacement

This study aimed to identify the prognostic value of the preoperative stroke volume ratio (right ventricular stroke volume/left ventricular stroke volume) for redilatation of the right ventricle after pulmonary valve replacement in patients with repaired tetralogy of Fallot.

From April 2004 to November 2013, 20 patients with repaired tetralogy of Fallot underwent pulmonary valve replacement for pulmonary valve regurgitation and right ventricular dilatation. Serial changes in ventricular volume were examined by cardiac magnetic resonance or computed tomography imaging. The redilatation ratio was calculated for right ventricular end-diastolic and end-systolic volume indices by dividing the increment in right ventricular volume from the first (median, 1.1 years) to the second (median, 3.2 years) evaluations after pulmonary valve replacement by the first evaluation. The relationships between the stroke volume ratio and redilatation ratio were assessed. The degree of right ventricular myocardial fibrosis was examined in 13 patients and compared with the stroke volume ratio.

Right ventricular volume (redilatation) significantly increased from a median of 1.1 to 3.2 years after pulmonary valve replacement. Significant positive correlations were detected between the stroke volume ratio and redilatation ratio of the right ventricular end-diastolic (r = 0.50. p = 0.02) and end-systolic volume indices (r = 0.49, p = 0.03). The stroke volume ratio also showed a significant positive correlation with the degree of right ventricular myocardial fibrosis (r = 0.73, p = 0.005).

The preoperative stroke volume ratio can predict redilatation of the right ventricle after pulmonary valve replacement and the degree of right ventricular myocardial fibrosis.