Vismara Riccardo, Leopaldi Alberto M, Piola Marco, Asselta Chiara, Lemma Massimo, Antona Carlo, Redaelli Alberto, van de Vosse Frans, Rutten Marcel, Fiore Gianfranco B
Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy ; Forcardiolab, Fondazione per la ricerca in Cardiochirurgia ONLUS, Milan, Italy .
Life Tec Group, Eindhoven, The Netherlands.
Med Eng Phys. 2016 Apr;38(4):346-53. doi: 10.1016/j.medengphy.2016.01.007. Epub 2016 Feb 19.
Recent approaches to the in vitro experimental study of cardiac fluid mechanics involve the use of whole biological structures to investigate in the lab novel therapeutic approaches for the treatment of heart pathologies. To enhance reliability and repeatability, the influence of the actuation strategy of the experimental apparatuses on the biomechanics of biological structures needs to be assessed. Using echography and intracardiac high-speed imaging, we compared the mitral valve (MV) anatomo-functional features (coaptation areas/lengths, papillary muscles-valvular plane distances) in two passive-beating-heart mock loops with internal (IPML) or external (EPML) pressurization of the ventricular chamber. Both apparatuses showed fluid dynamic conditions that closely resembled the physiology. The MVs analyzed in the EPML presented coaptation areas and lengths that were systematically higher, and exhibited greater variability from early-to peak-systole, as compared to those in the IPML. Moreover, in the EPML, the MV leaflets exhibited a convexity with high curvature toward the atrium. With the IPML, MV coaptation lengths ranged similar to available clinical data and the papillary muscles-valve plane distances were more stable throughout systole. In conclusion, both the apparatuses allow for reproducing in vitro the left heart hemodynamics, in terms of flow rates and pressures, with proper mitral valve continence. Results suggest that the IPML is more suitable for replicating the physiological MV functioning, while the EPML may have more potential as a model for the study of MV pathologies.
近期心脏流体力学的体外实验研究方法涉及使用完整的生物结构，在实验室中探究治疗心脏疾病的新型治疗方法。为提高可靠性和可重复性，需要评估实验装置的驱动策略对生物结构生物力学的影响。我们使用超声心动图和心内高速成像技术，比较了两个被动搏动心脏模拟环路中二尖瓣（MV）的解剖功能特征（贴合面积/长度、乳头肌与瓣膜平面的距离），这两个模拟环路分别采用心室腔内部（IPML）或外部（EPML）加压。两种装置均显示出与生理状况极为相似的流体动力学条件。与IPML中的二尖瓣相比，EPML中分析的二尖瓣的贴合面积和长度系统性更高，并且从收缩早期到峰值期表现出更大的变异性。此外，在EPML中，二尖瓣小叶朝向心房呈现出高曲率的凸面。在IPML中，二尖瓣贴合长度范围与现有临床数据相似，并且乳头肌与瓣膜平面的距离在整个收缩期更为稳定。总之，两种装置都能够在体外再现左心血流动力学，包括流速和压力，并具有适当的二尖瓣节制功能。结果表明IPML更适合复制二尖瓣的生理功能，而EPML作为二尖瓣病变研究模型可能具有更大的潜力。
