XXXX aortic and @entity1 dura mater valves: a comparative study in artificial hearts in @entity291 .

@entity1 @entity75 @entity3584 @entity653 @entity44013 @entity291
Thirty-one @entity3584 -treated @entity291 aortic valves (BAVs) and 105 @entity653 -treated @entity1 dura mater valves (HDVs) were used in 51 various artificial hearts up to 316 days in @entity291 . Multiple valves were implanted in the same animal under different hemodynamic conditions. A comparative study of these valves was performed in terms of blood compatibility and durability with relation to the different hemodynamic environments. Both BAVs and HDVs showed good blood compatibility. The degradation of collagen bundles of the valves began as early as 7 days in BAVs and 13 days in HDVs, and was seen in the hinged portions of the cusps. The fiber separation and resultant void formation were followed with insudation of blood elements and subsequent calcification. Calcification was dystrophic in nature and was encountered in 70.9% of BAVs and 7.6% of HDVs. All 17 BAVs used more than 30 days were calcified; in HDVs the earliest @entity75 was seen in a 78 day specimen. The pathological changes were more severe in the left side than the right of the total artificial hearts. These results clearly indicated that the @entity44013 is more durable than the @entity3584 -treated BAV. It was suggested that degradation of these tissue valves is greatly affected by the degree of hemodynamic stress on the valve cusp. Although @entity3584 treatment has increased the durability of tissue valves in general, the structure of the valve tissue also plays an important role in long-term durability.
