Early graft failure of small-sized porcine valved conduits in reconstruction of the right ventricular outflow tract.

BACKGROUND

The quest for an alternative to homografts for reconstruction of the right ventricular outflow tract is ongoing. The Shelhigh No-React (NR-4000PA series) treated porcine pulmonic valve conduit (SPVC) was developed as a potential alternative.

METHODS

During a 12-month period from May 2004 to May 2005, the SPVC was implanted in 34 patients, of whom 62% were younger than 1 year. Median age at operation was 7 months (range, 5 days to 12 years). Thirteen SPCV conduits size 10, 11 size 12, 8 size 14, and 2 size 16 were initially implanted. Since May 2005, however, we have temporarily abandoned its implantation as we were concerned about a number of early failures.

RESULTS

Until November 2005, 1 early and 1 late death have occurred. Both were not conduit related. Fifteen conduits were replaced in 13 patients. Of these, 10 were size 10, 3 size 12, 2 size 14, and none size 16. Mean time to replacement of the SPVC was 313 +/- 116 days. A pseudointimal peel formation and chronic inflammation with foreign-body reaction was found in all explanted conduits at all levels. The maximum of the inflammatory reaction occurred at the valvular level around the porcine tissues, with shrinkage of the valve and hemodynamic compromise. At valvular level, small punctuate calcifications were observed in 2 cases. In 6 patients an acute inflammatory component was observed. At late follow-up (mean follow-up 366 +/- 102 days, 34 patient-years), echocardiography showed a mean graft gradient of 39.8 +/- 29.7 mm Hg, with mild to moderate insufficiency in 4 patients.

CONCLUSIONS

Although the No-React treated valve largely resists calcification, pseudointimal peel formation was found in all explanted conduits and led to multilevel conduit stenoses. The small-sized SPVC can not be regarded as an ideal conduit for right ventricular outflow tract reconstruction.