Long-term Hemodynamic Assessment ofthePorcine Heterograft intheMitral Position LateDevelopment ofValvular Stenosis

SUMMARY Weundertook astudy ofpatients whohadporcine mitral valves inplace for more than 5 years andwhohadnoclinical signs orsymptoms suggestive ofvalve dysfunction. Ofthefirst 54patients whohadporcine valves implanted inthemitral position, 18wereavailable forcatheterization; allhada routine hemodynamic study postoperatively (mean 7months) forcomparison. Meanfollow-up was85months (range 61-111 months). Compared with theearly postoperative data, there was a significant increase inmean mitral valve gradient, from5.9 ± 0.7to8.6 ± 0.7 mm Hg(p< 0.01), andasignificant decrease incalculated mitral valve area,from2.2 ± 0.2to1.7 ± 0.2cm2(p< 0.01). Moreover, sevenpatients showed adecrease invalve area greater than 1.0 cm2,five with valves inplace for morethan 80months andonly twoof11patients with valves in place for80months orless (p<0.05). We conclude that there isa significant incidence ofhemodynamic deterioration ofporcine heterografts inthemitral position forgreater than 5 years,eveninpatients whoare clinically stable. THE GLUTARALDEHYDE-STABILIZEDporcine heterograft isthevalve ofchoice formitral valve replacement inmanycenters. Numerous investigators havefound acceptable hemodynamic performance of porcine heterografts inthemitral position when studied shortly after implantation."'6 However, there hasbeenconcern that theporcine heterograft would undergo thesamefate asother bioprostheses: late deterioration.74@ Pathologic studies haverevealed ex