Images in Cardiovascular Medicine Left Ventricular Assist Device-Related Systolic Aortic Regurgitation
Images in Cardiovascular Medicine Left Ventricular Assist Device-Related Systolic Aortic Regurgitation
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心血管医学图像 左心室辅助装置相关的收缩期主动脉瓣关闭不全
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
J. Lahpor
中科院分区：
文献类型：
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作者：
J. Martina;N. Jonge;E. Sukkel;J. Lahpor
一名39岁女性在心脏移植过程中接受了经食管超声心动图检查，此前接受了2.5年的连续流左心室辅助装置（cf-LVAD）支持。患者在供体心脏可用时入院，在cf-LVAD支持下未出现任何心力衰竭症状或体征。彩色血流成像显示明显的收缩期主动脉瓣返流（AR），而LVAD提供了充分的支持。这种不寻常的LVAD相关收缩期AR的发展可能涉及一种未知机制的主动脉瓣流动阻力的动态变化。在大多数涉及cf-LVAD支持和主动脉瓣关闭不全的病例中，AR表现为轻度至中度舒张期或连续性瓣膜关闭不全。1令人惊讶的是，患者在使用Heartmate II LVAD（Thoratec Corp，普莱森顿，CA）支持时表现出明显的收缩期AR（图1和仅在线数据补充中的电影）。当时，心电图显示低电压和广泛的T-top异常，但与之前的登记相比没有变化（图2）。此外，在LVAD支持下，胸部X线检查未显示心脏扩张和失代偿迹象（图3）。在超声心动图评估时，泵速设置为9400 rpm时，平均动脉压为非搏动性（平均值为70 mm Hg）。提示收缩期AR的发生可能与主动脉瓣沿着关闭时主动脉瓣血流阻力的动态变化有关。允许收缩期AR出现的机制尚未得到解释。因此，当主动脉瓣持续关闭且同时关闭不全时，主动脉AR可能在整个心动周期中发生。可能是收缩期主动脉瓣的流动阻力降低而不是舒张期主动脉瓣的流动阻力降低可能导致该患者出现明确的收缩期AR。因此，LVAD支持期间主动脉瓣环和瓣叶的动态运动可以解释这种现象。同样，cf-LVAD的湍流模式引起的瓣叶周围的局部压力扰动也可能是一个潜在原因。即便如此，我们不知道这种现象是由cf-LVAD的纯生理效应引起的，还是主要涉及解剖因素。可能与心脏移植时功能良好的cf-LVAD相关，没有证据表明该患者的收缩期AR具有任何血流动力学意义。因此，更详细的评估策略见图1。(A)心脏收缩期使用连续流LVAD支持的患者经食管超声心动图胸骨旁长轴的彩色多普勒标测。该图像显示了主动脉瓣关闭时的收缩期AR（箭头），沿着出现二尖瓣AR（箭头）。(B)在舒张期未观察到AR。这证实了该患者AR的明确收缩性质。LVAD表示左心室辅助装置; AR表示主动脉瓣返流。
A 39-year-old woman underwent transesophageal echocardiography during heart transplantation after 2.5 years of support with a continuous-flow left ventricular assist device (cf-LVAD). The patient was admitted to the hospital when a donor heart became available, and did not present with any symptoms or signs of heart failure on cf-LVAD support. Color-flow imaging demonstrated pronounced systolic aortic regurgitation (AR) while the LVAD was providing full support. The development of this unusual LVAD-related systolic AR may involve dynamic changes in resistance to flow of the aortic valve of an unknown mechanism. In most cases involving a combination of cf-LVAD support and aortic valve incompetence, AR would manifest as a mild-to-moderate diastolic or continuous valve regurgitation.1 Surprisingly, the patient demonstrated pronounced systolic AR (Figure 1and Movie in the online-only Data Supplement) on support with a Heartmate II LVAD (Thoratec Corp, Pleasanton, CA). At that time, the electrocardiogram showed low voltage and widespread T-top abnormalities, but was not changed in comparison with previous registrations (Figure 2). Furthermore, the chest x-ray showed no signs of heart dilation and decompensation while on LVAD support (Figure 3). Mean arterial pressures were nonpulsatile (mean, 70 mm Hg) at a pump speed setting of 9400 rpm at the time of echocardiography assessment. It is suggested that the development of systolic AR might be related to dynamic changes in the resistance to flow of the aortic valve along with consistent aortic valve closure. The mechanism allowing systolic AR to manifest has yet to be explained. Hence, when the aortic valve would be consistently closed and incompetent at the same time, aortic AR might occur throughout the entire cardiac cycle. It is possible that decrease in resistance to flow of the aortic valve during systole rather than diastole may have caused explicitly systolic AR in this patient to manifest. Accordingly, dynamic movements of the aortic valve annulus and valve leaflets during LVAD support may explain this phenomenon. Similarly, local pressure disturbances around the valve leaflets induced by turbulent flow patterns of the cf-LVAD may be a potential cause as well. Even so, we do not know whether this phenomenon is caused by purely physiological effects of the cf-LVAD, or it involves primarily anatomic factors. Perhaps in association with good-functioning cf-LVAD at the time of heart transplantation, no evidence was found that indicates that the systolic AR carried any hemodynamic significance in this patient. Thus, more detailed assessment strategies are Figure 1. (A) Color Doppler mapping of the parasternal long axis with transesophageal echocardiography of a patient supported by a continuous-flow LVAD during systole. This image shows systolic AR while the aortic valve is closed (arrow) along with coexistence of mitral AR (arrowhead). (B) Through the diastolic phase no AR is observed. This confirms the explicit systolic nature of the AR in this patient. LVAD indicates left ventricular assist device; AR, aortic regurgitation.