Purpose

The paper present findings from an in vitro experimental study of a stentless human aortic bioprosthesis (HAB) made of bacterial cellulose (BC). Three variants of the basic model were designed and tested to identify the valve prosthesis with the best performance parameters. The modified models were made of BC, and the basic model of pericardium.

Methods

Each model (named V₁, V₂ and V₃) was implanted into a 90 mm porcine aorta. Effective Orifice Area (EOA), rapid valve opening time (RVOT) and rapid valve closing time (RVCT) were determined. The flow resistance of each bioprosthesis model during the simulated heart systole, i.e. for the mean differential pressure (ΔP) at the time of full valve opening was measured. All experimental specimens were exposed to a mean blood pressure (MBP) of 90.5 ± 2.3 mmHg.

Results

The V₃ model demonstrated the best performance. The index defining the maximum opening of the bioprosthesis during systole for models V₁, V₂ and V₃ was 2.67 ± 0.59, 2.04 ± 0.23 and 2.85 ± 0.59 cm², respectively. The mean flow rate through the V₃ valve was 5.7 ± 1, 6.9 ± 0.7 and 8.9 ± 1.4 l/min for stroke volume (SV) of 65, 90 and 110 mL, respectively. The phase of immediate opening and closure for models V₁, V₂ and V₃ was 8, 7 and 5% of the cycle duration, respectively. The mean flow resistance of the models was: 4.07 ± 2.1, 4.28 ± 2.51 and 5.6 ± 2.32 mmHg.

Conclusions

The V₃ model of the aortic valve prosthesis is the most effective. In vivo tests using BC as a structural material for this model are recommended. The response time of the V₃ model to changed work conditions is comparable to that of a healthy human heart. The model functions as an aortic valve prosthesis in in vitro conditions.

中文翻译：

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细菌纤维素制成的无支架主动脉生物假体的体外研究

目的

该论文介绍了由细菌纤维素 (BC) 制成的无支架人主动脉生物假体 (HAB) 的体外实验研究结果。设计并测试了基本模型的三个变体，以确定具有最佳性能参数的瓣膜假体。修改后的模型采用BC制作，基础模型为心包。

方法

将每个模型（命名为V ₁、V ₂和V ₃）植入 90 mm 的猪主动脉中。确定有效孔口面积（EOA）、快速阀门打开时间（RVOT）和快速阀门关闭时间（RVCT）。测量模拟心脏收缩期间每个生物假体模型的流动阻力，即瓣膜完全打开时的平均压差(ΔP ) 。所有实验样本的平均血压 (MBP) 为 90.5 ± 2.3 mmHg。

结果

V ₃型号展示了最佳性能。对于模型V ₁、V ₂和V _{3 ，}定义生物假体在收缩期间的最大开口的指数分别为2.67±0.59、2.04±0.23和2.85±0.59cm ²。对于每搏输出量 (SV) 65、90 和 110 mL，通过V ₃阀的平均流速分别为 5.7 ± 1、6.9 ± 0.7 和 8.9 ± 1.4 l/min。模型V ₁、V ₂和V ₃的立即打开和关闭的阶段分别是循环持续时间的8%、7%和5%。模型的平均流阻为：4.07 ± 2.1、4.28 ± 2.51 和 5.6 ± 2.32 mmHg。

结论

V ₃模型的主动脉瓣假体是最有效的。建议使用 BC 作为该模型的结构材料进行体内测试。V ₃模型对工作条件变化的响应时间与健康人心脏的响应时间相当。该模型在体外条件下充当主动脉瓣假体。