Long-term results after right ventricular outflow tract reconstruction with porcine bioprosthetic conduits

Elastic fibers in the aortic valve spongiosa: a fresh perspective on its structure and role in overall tissue function

This study characterizes the elastic fiber structure within the aortic valve spongiosa, the middle layer of the tri-laminate leaflet. The layer is rich in glycosaminoglycans and proteoglycans, through which it resists compression and lubricates shear between the outer layers. Elastin in this layer forms a fine, interweaving structure, yet it is unclear how this particular structure, which uses elasticity to preload the leaflet, assists spongiosa function. In this study, immunohistochemistry (IHC) and scanning electron microscopy (SEM) are used to characterize spongiosa elastin, as well as investigate regional differences in structure. IHC for elastin highlights an intermediate structure which varies in thickness and density between regions. In particular, the spongiosa elastin is thicker in the hinge and coaptation region than in the belly. SEM of NaOH-digested leaflets shows a rectilinear pattern of elastic fibers in the hinge and coaptation region, as opposed to a radially oriented stripe pattern in the belly. In conclusion, elastic fibers in the spongiosa connect the two outer layers and vary regionally in structure, while possibly playing a role in responding to regionally specific loading patterns.

Initial Experience With a Bicuspid Polytetrafluoroethylene Pulmonary Valve in 41 Children and Adults: A New Option For Right Ventricular Outflow Tract Reconstruction

BACKGROUND

As the population of children with repaired congenital heart disease ages, an increasing number of patients will benefit from pulmonary valve insertion. We report our initial experience in 41 consecutive patients treated with placement of a surgically created polytetrafluoroethylene bicuspid pulmonary valve.

METHODS

A bicuspid pulmonary valve with orifice size greater than 24 mm is created with polytetrafluoroethylene and sutured into the right ventricular outflow tract. To obviate the need for reoperation in growing children, this technique is limited to older children and adults. Polytetrafluoroethylene bicuspid pulmonary valves were placed in 41 patients (age: range, 5.0 to 64.7 years, median = 15.7 years; weight: range, 14.2 to 99.0 kilograms, median, 52.0 kg). All patients had pulmonary insufficiency, pulmonary stenosis, or both, after previous intervention for tetralogy of Fallot (27), pulmonary stenosis (11), pulmonary atresia with intact ventricular septum (2), or double outlet right ventricle (1).

RESULTS

All patients left the operating theater with transesophageal echocardiography documenting no pulmonic stenosis and zero to trace pulmonic insufficiency. Median hospital length of stay was 5 days (range, 3 to 15 days; mean, 5.8 days). Follow-up including echocardiography ranged from 0.2 to 3.1 year (median follow-up, 1.5 years) and revealed significant improvement in New York Heart Association Classification, pulmonary insufficiency, and right ventricular end diastolic dimension.

CONCLUSIONS

Polytetrafluoroethylene bicuspid pulmonary valve reconstruction of the right ventricular outflow tract is a safe, effective, and durable technique for the short term. Appropriate oversizing minimizes outflow tract obstruction while maximizing competence. Long-term follow-up is necessary to determine the true value of this technique.

Novel technique for extending the use of allografts in cardiac operations

Small cryopreserved allografts for use in neonates and infants are increasingly difficult to find. We describe a technique for surgically reducing the size of the more readily available large-diameter allografts to make them conform to size requirements appropriate for neonates and infants. This technique involves a longitudinal incision of the allograft from its muscular annulus to its distal orifice with the excision of a single valve leaflet. The two commissural posts of the excised leaflet and the wall of the allograft are then reapproximated with fine suture. Four patients ranging in age from 14 days to 11 months (mean age, 5.2 months) and ranging in weight from 3 to 8.4 kg (mean weight, 5.2 kg) underwent reconstruction of the right ventricular outflow tract using this surgical technique. Two patients underwent repair of truncus arteriosus (age, 14 days and 16 days) and two patients underwent Rastelli operations (age, 9 months and 11 months). The mean follow-up time was 22.5 months (range, 14 to 28 months). All 4 patients are alive and well. One patient requires digoxin and furosemide for moderate quadricuspid truncal valve insufficiency. Serial echocardiography documents mild allograft stenosis in 2 patients and trivial to mild allograft insufficiency in 2 patients. Because handling characteristics and lower bleeding risks render allograft conduits preferable to synthetic conduits and, furthermore, because conduit insertion of any type in the neonate will eventually be outgrown and require replacement, we find this technique to be justifiable as a therapeutic option. In the short term, the technique results in excellent functional results and provides an alternative to synthetic conduits when an appropriate sized allograft is unavailable.