Timing of pulmonary valve replacement: can we use the same volumetric thresholds in repaired tetralogy of Fallot and pulmonary stenosis?

The timing of pulmonary valve replacement in patients with pulmonary regurgitation following treatment of pulmonary stenosis is undefined. Although cardiac magnetic resonance-based right ventricular volumes in tetralogy of Fallot patients have been used as a guide in pulmonary stenosis patients, anatomic differences between tetralogy of Fallot and pulmonary stenosis patients complicate their application to pulmonary stenosis patients and could result in late referral for pulmonary valve replacement. We sought to determine if pulmonary stenosis patients referred for pulmonary valve replacement were at greater risk for morbidity or need for tricuspid valve intervention at the time of pulmonary valve replacement. A retrospective cohort study was performed on all adult patients with a diagnosis of pulmonary stenosis or tetralogy of Fallot followed at our centre. Clinical and imaging-based exposures were collected. Pre-specified endpoints included need for concomitant tricuspid valve repair or replacement and pre- and post-pulmonary valve replacement cardiac magnetic resonance-based volumetric measurements. Between 1/1999 and 1/2020, 235 patients underwent pulmonary valve replacement for pulmonary regurgitation (52 with pulmonary stenosis, 183 with tetralogy of Fallot). Pulmonary stenosis patients were more likely to have at least moderate tricuspid regurgitation (p = 0.010), undergo concomitant tricuspid valve intervention (p = 0.003), and require tricuspid valve repair or replacement secondary to annular dilation (p = 0.027) compared to tetralogy of Fallot patients. There was no difference in pre-pulmonary valve replacement right ventricular size between pulmonary stenosis and tetralogy of Fallot patients. These findings suggest that referral for pulmonary valve replacement may be occurring later in the disease course for pulmonary stenosis patients.