Mansour Saba, Logan Emily, Antaki James F, Esmaily Mahdi
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA.
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA.
Comput Methods Programs Biomed. 2025 Nov;271:108947. doi: 10.1016/j.cmpb.2025.108947. Epub 2025 Jul 19.
Cardiovascular surgeries and mechanical circulatory support devices create non-physiological blood flow conditions that can be detrimental, especially for pediatric patients. A source of complications is mechanical red blood cell (RBC) damage induced by localized supraphysiological shear fields. To understand such complications in single ventricle patients, we introduce a multi-scale numerical model to predict hemolysis risk in idealized anatomies.
We employed our in-house CFD solver coupled with Lagrangian tracking and cell-resolved fluid-structure interaction to measure flow-induced stresses and strains on the RBC membrane. The Norwood procedure, known for its high mortality rate, is selected for its importance to single-ventricle population survival. We simulated three anatomies including 2.5 mm and 4.0 mm diameter modified Blalock-Taussig shunts (mBTS) and a 2.5 mm central shunt (CS), with hundreds of RBCs per case for statistical analysis.
The results show that the conditions created by these surgeries can elongate RBCs by more than two-fold (3.1% of RBCs for 2.5 mm mBTS, 1.4% for 4 mm mBTS, and 8.8% for CS). Shear and areal strain metrics also reveal that CS creates the greatest deformations on the RBC membrane. These conclusions are further confirmed when strain history and different damage thresholds are considered.
The central shunt is more hemolytic in comparison to the modified Blalock-Taussig shunt. Between the two mBTSs, the smaller diameter is slightly more prone to hemolysis. Spatial damage maps produced based on the studied metrics, highlighted hot zones that match the clinical images of shunt thrombosis, demonstrating their potential to enhance cardiac surgery outcomes.
心血管手术和机械循环支持设备会产生非生理性的血流状况，这可能是有害的，尤其是对儿科患者而言。并发症的一个来源是局部超生理性剪切场导致的机械性红细胞（RBC）损伤。为了了解单心室患者的此类并发症，我们引入了一个多尺度数值模型来预测理想化解剖结构中的溶血风险。
我们使用内部计算流体动力学（CFD）求解器，结合拉格朗日追踪和细胞分辨的流固相互作用，来测量红细胞膜上的流动诱导应力和应变。诺伍德手术因其对单心室患者群体生存的重要性而被选中，尽管其死亡率较高。我们模拟了三种解剖结构，包括直径为2.5毫米和4.0毫米的改良布莱洛克 - 陶西格分流术（mBTS）以及一个2.5毫米的中央分流术（CS），每种情况有数百个红细胞用于统计分析。
结果表明，这些手术所产生的状况可使红细胞伸长超过两倍（2.5毫米mBTS的红细胞中有3.1%，4毫米mBTS的为1.4%，CS的为8.8%）。剪切和面积应变指标还表明，CS对红细胞膜产生的变形最大。当考虑应变历史和不同损伤阈值时，这些结论得到了进一步证实。
与改良布莱洛克 - 陶西格分流术相比，中央分流术的溶血作用更强。在两种mBTS中，较小直径的稍微更容易发生溶血。基于所研究指标生成的空间损伤图突出显示了与分流血栓形成临床图像相匹配的热点区域，证明了它们在改善心脏手术结果方面的潜力。
