Early pulmonary homograft failure from dilatation due to distal pulmonary artery stenosis

Outcomes Following Heterotopic Placement of Right Ventricle to Pulmonary Artery Conduits

BACKGROUND

We sought to evaluate the outcomes following right ventricle to pulmonary artery (RV-PA) conduit placement in pediatric patients, excluding those with a RV-PA conduit for the Ross procedure which is associated with improved conduit durability, partly related to its orthotopic position.

METHODS

Outcomes for 119 patients who underwent RV-PA conduit placement at a single institution from January 2004 to December 2016 were reviewed. Primary outcome measures were reintervention-free survival (RFS) and overall survival. Survival analyses were performed using the Kaplan-Meier method, and risk factors associated with reintervention were evaluated.

RESULTS

The median age at the time of conduit placement was 6 months (interquartile range, IQR: 1-14), and the median length of follow-up was 63 months (range: 0-156). During follow-up, 39 patients required conduit-related reintervention, while 6 patients died perioperatively with an overall survival of 90% at 10 years. Among the remaining 113 patients, the RFS at one, five, and ten years was 91% (84%-95%), 72% (60%-80%), and 33% (16%-50%), respectively. The median time to conduit replacement in the series was 43.5 months (IQR: 19.3-76.2). The use of a pulmonary homograft was associated with improved RFS (P = .03), and this was particularly pronounced in comparison with aortic homografts in neonates. Infection was the indication for replacement in only one patient.

CONCLUSIONS

The majority of the conduits placed during the neonatal period required conduit replacement before the age of five years. Endocarditis was not a common indication for replacement. In neonates and infants, we prefer pulmonary homografts for most indications.

Current status of right ventricular outflow tract reconstruction: complete translation of a review article originally published in Kyobu Geka 2014;67:65-77

Right ventricular outflow tract (RVOT) reconstruction is becoming more prevalent as the number of adult patients who require repeated surgery long after definitive repair of congenital heart defects during childhood has increased. Early primary repair and annulus-preserving surgery have been the two current strategies of RVOT reconstruction from the viewpoint of timing and indications for surgical intervention; however, the long-term outcomes of both procedures remain unknown. Although various materials have been used for pulmonary valve replacement during RVOT reconstruction, deficient durability due primarily to immunological rejection frequently arises, particularly when implanted into young patients. A multicenter study in Japan showed that the clinical outcomes of expanded polytetrafluoroethylene (ePTFE) valved patches/conduits that we developed and manufactured comprised an excellent alternative material for RVOT reconstruction. Such enhanced outcomes might have partly been attributable to the biocompatibility and low antigenicity of ePTFE, and also to the fluid dynamic properties arising from the structural characteristics of a bulging sinus and a fan-shaped valve. However, numerous issues concerning RVOT reconstruction, such as indications for and the timing of definitive repair, as well as the choice of materials for pulmonary valve replacement, must be resolved to achieve better patient prognoses and quality of life. This review describes recent surgical strategies and outstanding issues associated with RVOT reconstruction.

Options for prosthetic pulmonary valve replacement

This article reviews current data on various prostheses utilized for pulmonary valve replacement. Durability data is reviewed and risk factors for deterioration are examined. Finally, the choice of prosthesis should be tailored to the specific clinical scenario based on existing data regarding durability and risk factors.

Right ventricle to pulmonary artery conduit augmentation compared with replacement in young children

BACKGROUND

Targeted outcome data for young children undergoing right ventricle to pulmonary artery conduit reoperation are sparse, as are data on the use of conduit augmentation as an alternative to conduit replacement at the time of first conduit reoperation (conduit 2).

METHODS

We conducted a retrospective chart review including baseline data, operative data, and cross-sectional follow-up on children younger than 10 years of age undergoing a first conduit reoperation (n = 180), comparing conduit replacement (n = 147, 82%) with conduit augmentation (n = 33, 18%).

RESULTS

There were no differences between the two groups with respect to age, size, or hemodynamic variables. Augmentation was less often performed in patients with an aortic homograft and by one surgeon. At conduit 2, cardiopulmonary bypass time was longer in replacement patients (101 +/- 35 versus 71 +/- 34 minutes; p < 0.001); cardiac intensive care unit stay was not different. Early mortality was 0.5%, and overall 10-year survival was 95%. Freedom from reoperation was 80% at 5 years and 39% at 10 years, whereas freedom from reintervention (reoperation or catheter intervention) was 55% at 5 years and 26% at 10 years, with no differences between groups. Aortic homograft as a first conduit was associated with shorter freedom from reoperation. Limiting analysis to conduits that were replaced at conduit 2, undersized conduits were associated with shorter freedom from reoperation and smaller body surface area, and undersized conduits were associated with shorter freedom from reintervention.

CONCLUSIONS

Freedom from a second conduit reoperation after a first conduit replacement was shorter in smaller children and undersized conduits. Conduit augmentation offers similar clinical outcomes in selected patients.

Factors influencing late allograft valve failure

Allograft valves are a valuable valve replacement substitute in the surgical management of heart valve disease. It remains the valve substitute of choice in the reconstruction of the right ventricular outflow tract in children with congenital heart disease and in the Ross procedure. However, its durability remains suboptimal, particularly in children. This article reviews the mechanisms and factors implicated in late allograft dysfunction, with a focus on the evidence for an immunological cause for allograft valve failure. Unravelling the mechanisms of allograft valve failure may allow modification of the allograft to improve its long-term durability.

Cryopreserved homografts in the pulmonary position: determinants of durability

BACKGROUND

The cryopreserved homograft has emerged as the pulmonary conduit of choice for the repair of many congenital heart defects. It is also used for pulmonary valve replacement in the Ross procedure. Because of a wide range of patient ages and diagnoses, the risk of homograft failure may vary.

METHODS

We reviewed 185 consecutive pulmonary position implants performed between September 1985 and January 1999. We examined three age groups: patients less than 1 year of age (n = 53), patients 1 to 10 years of age (n = 46), and patients more than 10 years of age (n = 86).

RESULTS

Five-year Kaplan-Meier homograft survival was 25%, 61%, and 81% for the groups, respectively (p < 0.02). Smaller homograft size, younger patient age, and truncus arteriosus were risk factors for homograft failure in univariate analysis (p < 0.05). Smaller homograft size was the only predictor for homograft failure in multivariate analysis (p < 0.001). Twenty of 99 implants in patients less than 10 years old underwent transcatheter intervention. The 3-year Kaplan-Meier implant survival of this group (79%) was not different from those who did not undergo intervention (77%, p = 0.84). Survival of aortic and pulmonary homografts in patients less than 10 years of age was not different (p = 0.35). Ross procedure implants appear to have optimal survival (94%) at 5 years. Non-Ross implants in patients more than 10 years of age have 76% 5-year Kaplan-Meier survival, which is not different from Ross patients (p = 0.33).

CONCLUSIONS

Small homografts have limited durability. Aortic homografts perform as well as pulmonary homografts in young patients. Once patients receive an "adult-size" homograft, at approximately 10 years of age, risk for implant failure approximates that of patients undergoing the Ross procedure. Transcatheter interventions, when indicated, may prolong homograft life.

Cryopreserved homograft valves in the pulmonary position: risk analysis for intermediate-term failure

OBJECTIVE

The purpose of this study was to examine the durability of cryopreserved homografts used to replace the "pulmonary" valve and to identify factors associated with their late deterioration.

METHODS

We reviewed our entire experience (1985-1997) with 331 survivors in whom cryopreserved homograft valves (pulmonary, n = 304; aortic, n = 27) were used to reconstruct the pulmonary outflow tract. Median age was 14 years (range, 2 days-62 years). Operations included Ross operation (n = 259), tetralogy of Fallot (n = 41), truncus arteriosus (n = 14), Rastelli operation (n = 11), and others (n = 6). Median follow-up was 3.8 years (range, 0.2-11.2 years); late echographic follow-up was complete for 97% of patients. Homograft failure was defined as the need for explantation and valve-related death; homograft dysfunction was defined as a pulmonary insufficiency grade 3/4 or greater and a transvalvular gradient of 40 mm Hg or greater.

RESULTS

Homograft failure occurred in 9% (30 of 331 patients; Kaplan-Meier); freedom from failure was 82% +/- 4% at 8 years. Homograft dysfunction occurred in 12% (39 of 331 patients), although freedom from dysfunction was 76% +/- 4% at 8 years. For aortic homografts, this was 56% +/- 11%, compared to 80% +/- 4% for pulmonary homografts (P =.003). For patients aged less than 3 years (n = 38), this was 51% +/- 12%, compared with 87% +/- 4% for older patients (P =.0001). By multivariable analysis, younger age of homograft donors, non-Ross operation, and later year of operation were associated with homograft failure; younger age of homograft donors, later year of operation, and use of an aortic homograft were associated with homograft dysfunction.

CONCLUSIONS

Homograft valves function satisfactorily in the pulmonary position at mid-term follow-up. The pulmonary homograft valve appears to be more durable than the aortic homograft valve in the pulmonary position.