Pulmonary artery and lung parenchymal growth following early versus delayed stent interventions in a swine pulmonary artery stenosis model

Abstract

Objectives: Compare lung parenchymal and pulmonary artery (PA) growth and hemodynamics following early and delayed PA stent interventions for treatment of unilateral branch PA stenosis (PAS) in swine. Background: How the pulmonary circulation remodels in response to different durations of hypoperfusion and how much growth and function can be recovered with catheter directed interventions at differing time periods of lung development is not understood. Methods: A total of 18 swine were assigned to four groups: Sham (n = 4), untreated left PAS (LPAS) (n = 4), early intervention (EI) (n = 5), and delayed intervention (DI) (n = 5). EI had left pulmonary artery (LPA) stenting at 5 weeks (6 kg) with redilation at 10 weeks. DI had stenting at 10 weeks. All underwent right heart catheterization, computed tomography, magnetic resonance imaging, and histology at 20 weeks (55 kg). Results: EI decreased the extent of histologic changes in the left lung as DI had marked alveolar septal and bronchovascular abnormalities (p = .05 and p < .05 vs. sham) that were less prevalent in EI. EI also increased left lung volumes and alveolar counts compared to DI. EI and DI equally restored LPA pulsatility, R heart pressures, and distal LPA growth. EI and DI improved, but did not normalize LPA stenosis diameter (LPA/DAo ratio: Sham 1.27 ± 0.11 mm/mm, DI 0.88 ± 0.10 mm/mm, EI 1.01 ± 0.09 mm/mm) and pulmonary blood flow distributions (LPA-flow%: Sham 52 ± 5%, LPAS 7 ± 2%, DI 44 ± 3%, EI 40 ± 2%). Conclusion: In this surgically created PAS model, EI was associated with improved lung parenchymal development compared to DI. Longer durations of L lung hypoperfusion did not detrimentally affect PA growth and R heart hemodynamics. Functional and anatomical discrepancies persist despite successful stent interventions that warrant additional investigation.

The impact of unilateral pulmonary artery stenosis on right ventricular to pulmonary arterial coupling in patients with transposition of the great arteries

“…Despite increased RV afterload, RV remodeling and function remained within normal limits using CMR. This is supported by animal studies showing limited RV hypertrophy in relationship to unilateral PA stenosis 22,23 . However, we found impaired RV contractility (Ees) and increased RV diastolic stiffness (Eed) using RV PV loop analysis and observed RV‐PA uncoupling in all patients.…”

“…This is supported by animal studies showing limited RV hypertrophy in relationship to unilateral PA stenosis. 22,23 However, we found impaired RV contractility (Ees) and increased RV diastolic stiffness (Eed) using RV PV loop analysis and observed RV-PA uncoupling in all patients. This is substantiated by an animal study that shows reduced RV contractility in the presence of unilateral PA stenosis, which did not restore after the intervention.…”

Congenital heart disease-associated pulmonary dysplasia and its underlying mechanisms

“…Reduced lung volume and impaired pulmonary function were observed in patients with CHD with RPF. A study on a swine pulmonary stenosis model demonstrated that early stenting intervention was associated with improved pulmonary development compared with delayed stenting intervention ( 39 ).…”

Calculating Relative Lung Perfusion Using Fluoroscopic Sequences and Image Analysis: The Fluoroscopic Flow Calculator

“…1 Maldistribution of Q p is associated with reduced oxygen consumption at anaerobic threshold, increased dyspnea, 2 and possibly decreased longitudinal growth of distal pulmonary arteries. 3,4 Currently, evaluation of the distribution of Q p requires either lung perfusion scintigraphy (LPS) 1,5,6 or a cardiac magnetic resonance (CMR) imaging study using velocity mapping (CMR). 7 These studies incur cost, time, and potentially expose patients to additional radiation and anesthesia.…”