Transcatheter Pulmonary Valve Replacement and Acute Increase in Diastolic Pressure are Associated with Increases in Both Systolic and Diastolic Pulmonary Artery Dimensions.

Stable positioning of a transcatheter pulmonary valve (TPV) in native outflow tracts depends on a clear understanding of underlying anatomy and outflow tract dimensions. We hypothesized that restoration of pulmonary competence may acutely alter these dimensions. A retrospective single-center review of consecutive patients after TPV placement from 2007 to 2014 was performed. Patients with less than moderate pulmonary regurgitation were excluded. We reviewed acute catheterization data on 46 patients, most with tetralogy of Fallot (70%). Baseline and post-implant (7.5 ± 3 min post-deployment) measurements of central pulmonary arteries (PAs) were determined angiographically. The right PA diameter increased (20 ± 4-24 ± 6 mm systole*, 16 ± 4-21 ± 6 mm diastole*), as did the left PA (20 ± 6-24 ± 8 mm systole*, 16 ± 5-21 ± 7 mm diastole*). PA pressures increased from averages of 29.3/10.6 (17) to 29.8/15.1 (21) mmHg. We noted that pre-implant systolic PA diameter correlated with diastolic PA diameter post-implant (r = 0.9). On follow-up catheterization in seven patients [median 3 years; (1-8)], combined central PA diameter decreased an average of 20% (systole: 20% ± 12, diastole: 18% ± 11) as compared to post-implant measurements. Acute pulmonary valve competence in patients with at least moderate pulmonary regurgitation results in an immediate increase in PA diameter (20% systole and 30% diastole). The cause of this diameter change is unclear. This acute change may have implications for device and patient selection (*p < 0.001).