School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China.
Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
Comput Math Methods Med. 2019 Feb 3;2019:1502318. doi: 10.1155/2019/1502318. eCollection 2019.
Studying the haemodynamics of the central shunt (CS) and modified Blalock-Taussig shunt (MBTS) benefits the improvement of postoperative recovery for patients with an aorta-pulmonary shunt. Shunt configurations, including CS and MBTS, are virtually reconstructed for infants A and B based on preoperative CT data, and three-dimensional models of A, 11 months after CS, and B, 8 months after MBTS, are reconstructed based on postoperative CT data. A series of parameters including energy loss, wall shear stress, and shunt ratio are computed from simulation to analyse the haemodynamics of CS and MBTS. Our results showed that the shunt ratio of the CS is approximately 30% higher than the MBTS and velocity distribution in the left pulmonary artery (LPA) and right pulmonary artery (RPA) was closer to a natural development in the CS than the MBTS. However, energy loss of the MBTS is lower, and the MBTS can provide more symmetric pulmonary artery (PA) flow than the CS. With the growth of infants A and B, the shunt ratio of infants was decreased, but maximum wall shear stress and the distribution region of high wall shear stress (WSS) were increased, which raises the probability of thrombosis. For infant A, the preoperative abnormal PA structure directly resulted in asymmetric growth of PA after operation, and the LPA/RPA ratio decreased from 0.49 to 0.25. Insufficient reserved length of the MBTS led to traction phenomena with the growth of infant B; on the one hand, it increased the eddy current, and on the other hand, it increased the flow resistance of anastomosis, promoting asymmetric PA flow.
研究中央分流器（CS）和改良的 Blalock-Taussig 分流器（MBTS）的血液动力学有助于改善主动脉-肺动脉分流术后患者的康复。根据术前 CT 数据，为婴儿 A 和 B 虚拟重建了 CS 和 MBTS 等分流器结构，并根据术后 CT 数据重建了婴儿 A 的 CS 术后 11 个月和婴儿 B 的 MBTS 术后 8 个月的三维模型。从模拟中计算出一系列参数，包括能量损失、壁面切应力和分流比，以分析 CS 和 MBTS 的血液动力学。我们的结果表明，CS 的分流比大约比 MBTS 高 30%，并且 CS 中的左肺动脉（LPA）和右肺动脉（RPA）中的速度分布比 MBTS 更接近自然发育。然而，MBTS 的能量损失较低，并且 MBTS 可以比 CS 提供更对称的肺动脉（PA）流量。随着婴儿 A 和 B 的成长，婴儿的分流比降低，但最大壁面切应力和高壁面切应力（WSS）分布区域增加，这增加了血栓形成的可能性。对于婴儿 A，术前异常的 PA 结构直接导致术后 PA 的不对称生长，LPA/RPA 比从 0.49 降低到 0.25。MBTS 的预留长度不足导致婴儿 B 生长时出现牵引现象；一方面增加了涡流，另一方面增加了吻合口的流动阻力，促进了不对称的 PA 流量。
