Decellularized Pulmonary Xenograft Matrix PplusN versus Cryopreserved Homograft for RVOT Reconstruction during Ross Procedure in Adults

Background Decellularized pulmonary homografts are being increasingly adopted for right ventricular outflow tract reconstruction in adult patients undergoing the Ross procedure. Few reports presented Matrix PplusN xenograft (Matrix) in a negative light. The objective of this study was to compare our midterm outcomes of Matrix xenograft versus standard cryopreserved pulmonary homograft (CPHG). Methods Eighteen patients received Matrix xenograft between January 2012 and June 2016, whereas 66 patients received CPHG. Using nonparametric statistical tests and survival analysis, we compared midterm echocardiographic and clinical outcomes between the groups. Results Except for significant age difference (the Matrix group was significantly older with 57 ± 8 years than the CPHG group, 48 ± 9 years, p = 0.02), the groups were similar in all other baseline characteristics. There were no significant differences in cardiopulmonary bypass times (208.3 ± 32.1 vs. 202.8 ± 34.8) or in cross-clamp times (174 ± 33.9 vs. 184.4 ± 31.1) for Matrix and CPHG, respectively. The Matrix group had significantly inferior freedom from reintervention than the CPHG group with 77.8 versus 98.5% (p = 0.02). Freedom from pulmonary valve regurgitation ≥ 2 was not significantly different between the groups with 82.4 versus 90.5% for Matrix versus CPHG, respectively. After median follow-up of 4.9 years, Matrix xenograft developed significantly higher peak pressure gradients compared with CPHG (20.4 ± 15.5 vs. 12.2 ± 9.0 mm Hg; p = 0.04). Conclusion After 5 years of clinical and echocardiographic follow-up, the decellularized Matrix xenograft had inferior freedom from reintervention compared with the standard CPHG. Closer follow-up is necessary to avoid progression of valve failure into right ventricular deterioration.

Right Ventricle Has Normal Myofilament Function But Shows Perturbations in the Expression of Extracellular Matrix Genes in Patients With Tetralogy of Fallot Undergoing Pulmonary Valve Replacement

Background Patients with repair of tetralogy of Fallot (rToF) who are approaching adulthood often exhibit pulmonary valve regurgitation, leading to right ventricle (RV) dilatation and dysfunction. The regurgitation can be corrected by pulmonary valve replacement (PVR), but the optimal surgical timing remains under debate, mainly because of the poorly understood nature of RV remodeling in patients with rToF. The goal of this study was to probe for pathologic molecular, cellular, and tissue changes in the myocardium of patients with rToF at the time of PVR. Methods and Results We measured contractile function of permeabilized myocytes, collagen content of tissue samples, and the expression of mRNA and selected proteins in RV tissue samples from patients with rToF undergoing PVR for severe pulmonary valve regurgitation. The data were compared with nondiseased RV tissue from unused donor hearts. Contractile performance and passive stiffness of the myofilaments in permeabilized myocytes were similar in rToF‐PVR and RV donor samples, as was collagen content and cross‐linking. The patients with rToF undergoing PVR had enhanced mRNA expression of genes associated with connective tissue diseases and tissue remodeling, including the small leucine‐rich proteoglycans ASPN (asporin), LUM (lumican), and OGN (osteoglycin), although their protein levels were not significantly increased. Conclusions RV myofilaments from patients with rToF undergoing PVR showed no functional impairment, but the changes in extracellular matrix gene expression may indicate the early stages of remodeling. Our study found no evidence of major damage at the cellular and tissue levels in the RV of patients with rToF who underwent PVR according to current clinical criteria.

Three-Year Outcomes From the Harmony Native Outflow Tract Early Feasibility Study

Background: The Harmony transcatheter pulmonary valve (TPV) was designed for treatment of postoperative pulmonary valve regurgitation in patients with repaired right ventricular outflow tracts. Methods: The Native TPV EFS (Early Feasibility Study) is a prospective, multicenter, nonrandomized feasibility study. Three-year outcomes are reported. Results: Of 20 implanted patients, 17 completed 3-year follow-up (maximum: 4.1 years). There were no deaths and 2 early explants. One patient did not complete the 3-year visit. In patients with available 3-year echocardiographic data, 1 had a mild paravalvular leak and the rest had none/trace; 1 patient had mild pulmonary valve regurgitation and the remainder had none/trace. The 3-year mean right ventricular outflow tract echocardiographic gradient was 15.7±5.5 mm Hg. Radiographically, no late frame fractures or erosions were identified. At 2 years, 2 patients presented with an increased echocardiographic outflow gradient (1 mixed lesion with moderate/severe pulmonary valve regurgitation). Computed tomography scans identified neointimal tissue ingrowth within the stent frame in both patients, and they were treated successfully with a transcatheter valve-in-valve procedure (Melody TPV). Additional follow-up computed tomography scans performed at 3.2±0.5 years after implant were obtained in 16 patients and revealed luminal tissue thickening at the inflow and outflow portion of the frame with no significant alteration of the valve housing. Conclusions: Three-year results from the Native TPV EFS revealed stable Harmony TPV device position, good valve function in most, and the absence of moderate/severe paravalvular leak and significant late frame fractures. Two patients developed significant neointimal proliferation requiring valve-in-valve treatment, while all others had no clinically significant right ventricular outflow tract obstruction. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01762124.

Surgical correction of a pulmonary artery aneurysm with severe pulmonary regurgitation with a valve-sparing technique

Pulmonary artery aneurysms are rare but are associated with a significant risk of rupture and dissection. Moreover, pulmonary valve regurgitation and/or stenosis often coexist. In this study, we present a case of a pulmonary artery aneurysm with severe pulmonary regurgitation in a patient with pulmonary hypertension treated with aneurysm resection and pulmonary valve repair.

Valve-sparing in tetralogy of Fallot: how to open the pulmonary valve

Pulmonary valve stenosis is characterized by high attachment of the commissures to the pulmonary arterial wall. Thus, the tethering of the fused leaflets should be separated from their anomalous insertion, with increased leaflet mobilization in each commissure, and the fusion between the leaflets should be incised until reaching the pulmonary annulus, providing complete opening of the pulmonary valve. This extended opening of pulmonary valve tethering can provide an additional increase of a few millimeters in the diameter of the pulmonary annulus, enough to completely relieve right ventricular outflow tract obstruction without creating pulmonary valve regurgitation.