Survival after stentless and stented xenograft aortic valve replacement: a concurrent, controlled trial

To define the impact of stentless versus stented valve design on survival late after xenograft aortic valve replacement, a retrospective analysis of all consecutive patients operated on between January 1992 and April 2000 was undertaken.

Two hundred ninety-two patients had stented (group 1) and 376 stentless (group 2) xenograft aortic valve replacements. Age was older in group 1 (75 +/- 4 vs 70 +/- 7 years, p = 0.01), whereas male gender and aortic stenosis were equally prevalent. Advanced New York Heart Association class III-IV (85% vs 78%, p = 0.03) and associated procedures (53% vs 41%, p = 0.01) were more common in group 1. Aortic cross-clamp (80 +/- 28 vs 96 +/- 23 minutes, p = 0.01) and bypass (91 +/- 56 vs 129 +/- 34 minutes, p = 0.01) times were shorter in group 1. Logistic regression and Cox proportional hazard methods were used to define the role of demographic and operative variables on hospital and late survival, freedom from valve-related mortality, and reintervention.

Early mortality was higher in group 1 (6.2% vs 2.6%, p = 0.02). Smaller aortic anulus (p = 0.008), aortic cross-clamp (p = 0.03), and coronary disease requiring bypass (p = 0.03) were associated with hospital mortality. During follow-up (37 +/- 30 vs 43 +/- 35 months, p = NS), 66 late deaths were recorded (12% vs 9%, p = NS). At 8 years, survival (70 +/- 5% vs 81 +/- 3%, p = 0.01), freedom from cardiac- (85 +/- 1% vs 92 +/- 3%, p = 0.02), and valve-related death (79 +/- 5% vs 95 +/- 2%, p = 0.004) were higher in group 2. Freedom from structural deterioration was similar (92 +/- 5% vs 93 +/- 3%, p = NS), but freedom from reoperation was lower in group 2 (99 +/- 1% vs 90 +/- 4%, p = 0.009). Multivariate analysis showed female gender (p = 0.02), age (p = 0.03), and smaller valve size (p = 0.05) to be associated with late mortality; age (p = 0.06) and diagnosis of aortic stenosis (p = 0.008) with cardiac mortality; longer intensive care unit stay (p = 0.001) and stented xenografts (p = 0.05) with valve-related mortality; and younger age (p = 0.01) and stentless xenograft (p = 0.05) with reoperation.

Use of stentless xenografts correlates with better survival and freedom from cardiac- and valve-related mortality than stented valves. However, bias favoring stented valves in older and sicker patients exists. Selective survival advantage of stentless xenograft is confined to valve-related mortality. Stentless valves are more likely to be replaced for dysfunction.