Stentless versus conventional xenograft aortic valve replacement: Midterm results of a prospectively randomized trial

Background. The purpose of this study was to analyze the 5- to 8-year clinical results after prospectively randomized stentless versus conventional aortic valve replacement. Methods. Two hundred twenty-three patients received stentless ( Freestyle or Toronto, n = 127) or conventional stented ( CE porcine, n = 96) xenograft aortic valve replacement between March 1996 and March 1999 using a prospectively randomized protocol and were discharged from the hospital. Patient age at operation was 71.8 = 6.7 years stentless and 74.9 = 4 years stented ( p < 0.05). There were no significant differences regarding preoperative morphologic and hemodynamic variables. Aortic annulus diameter indices were comparable at 13.5 mm stentless and 13.6 mm stented. Follow-up after 6.9 +/- 0.8 years is complete for 95.6% of the patients at a total of 1,533 patient-years. Analysis of variance, unpaired t test, univariate ( chi(2)), and survival analysis ( log rank) were performed. Results. Eight-year survival was 78.1% +/- 3.8% stentless versus 66% +/- 4.9% stented ( p = 0.04); mean survival was 97 months stentless versus 88 months stented. At most recent follow-up, New York Heart Association functional class was 1.6 +/- 0.6 stentless versus 1.5 +/- 0.7 stented ( p = not significant); ejection fraction was 61% +/- 11% versus 61% +/- 8% ( p = not significant); transvalvular maximum flow velocity was 23 +/- 9 mm Hg versus 37 +/- 15 mm Hg ( p < 0.01). Thrombembolic events occurred in 2 of 7 patients, including 2 of 6 patients suffering major stroke ( p = not significant). Most ( 93%) of the patients were satisfied with the postoperative course, having a significantly improved quality of life. Conclusions. Midterm results after xenograft aortic valve replacement are satisfactory. Overall survival is significantly better after stentless aortic valve replacement in this series. However, there was no cause and effect relationship between lower transvalvular pressure gradient. Fewer thrombembolic events and better survival rates were proven.