Zannoli Romano, Corazza Ivan, Cremonesi Alberto, Branzi Angelo
Institute of Cardiology, Policlinico S. Orsola-Malpighi, University of Bologna, Pad.21, via Massarenti, 9, 40138 Bologna, Italy.
J Biomech. 2007;40(14):3089-95. doi: 10.1016/j.jbiomech.2007.03.021. Epub 2007 May 4.
Stanford type A aortic dissection often rapidly leads to death from aortic rupture. We considered the possibility of introducing a passive counterpulsating damper into the dissected aorta in order to limit the physical stress associated with ventricular ejection and increase the diastolic aorto-ventricular pressure gradient. We conceived a damping device comprising an intravascular balloon connected to an adjustable external reservoir to regulate the air pressure inside the balloon, and performed a simulation study using a mechanical model of the cardiovascular system, mimicking aortic dissection. When the balloon was completely deflated, the behavior of the aortic pressure signal was typical of low-compliance aortic dissection, as characterized by an augmented maximum systolic value, accentuated diastolic decay, and a very low end-diastolic value. Balloon inflation (at incremental steps to 90 mmHg) progressively restored the aorto-ventricular pressure gradient and reduced peak systolic pressure values, leading to progressive improvements in the characteristics of the aortic pressure curve in terms of reduction in the maximum systolic value and slower diastolic decay. The proposed mechanism might exert beneficial effects at two levels: (1) directly, by reducing mechanical stress on the arterial wall; (2) indirectly, by allowing safer use of pharmaceutical agents (beta-blockers etc.). In vivo animal simulation studies are warranted to verify the effects of the device and optimize balloon shape and volume in a realistic pathophysiological setting.
A型主动脉夹层通常会迅速导致主动脉破裂死亡。我们考虑了在夹层主动脉中引入被动反搏阻尼器的可能性，以限制与心室射血相关的物理应力，并增加舒张期主动脉-心室压力梯度。我们构思了一种阻尼装置，它包括一个与可调节外部储液器相连的血管内球囊，用于调节球囊内的气压，并使用心血管系统的力学模型进行了模拟研究，模拟主动脉夹层。当球囊完全放气时，主动脉压力信号的表现是典型的低顺应性主动脉夹层，其特征是收缩压最大值增加、舒张期衰减加剧以及舒张末期值非常低。球囊充气（逐步增加至90 mmHg）逐渐恢复主动脉-心室压力梯度并降低收缩压峰值，导致主动脉压力曲线特征在最大收缩压值降低和舒张期衰减减慢方面逐步改善。所提出的机制可能在两个层面发挥有益作用：（1）直接作用，通过减少动脉壁上的机械应力；（2）间接作用，通过允许更安全地使用药物（β受体阻滞剂等）。有必要进行体内动物模拟研究，以验证该装置的效果，并在实际病理生理环境中优化球囊形状和体积。
