Heart failure: not just the heart but also the lungs.
Heart failure: not just the heart but also the lungs.
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心力衰竭：不仅是心脏，还有肺。
DOI：
10.1161/circimaging.112.981449
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Vasu,Sujethra
中科院分区：
文献类型：
--
作者：
Little,WilliamC;Vasu,Sujethra
690循环心脏血管成像2012年11月依赖部分(即后方)的血流灌注显著大于最不依赖部分(前部)的血流灌注。据推测，这反映了肺依赖部分的额外静水压力。使用HF时，这种重力梯度被钝化，与左心室舒张末压力成正比地减小。因此，在HF中，肺依赖区域的血流比流向前区的血流减少得更多。在多变量分析中，这种血流灌注改变与平均肺动脉压升高关系最为密切。这表明，与流体静力梯度相反的重新分布是由于肺血管收缩，这种收缩在肺的依赖部分更为明显。因此，血流被重新分配到依赖程度较低的肺部分。直立胸片上可见类似的头侧肺血流重分布，这是心衰的典型表现。HF患者卧床后呼吸困难更为严重(矫形呼吸)。很可能是曹等人描述的仰卧位血流的重新分配导致了矫形呼吸暂停。此外，在HF中，随着仰卧位时间的延长，外周血容量的扩张和中心重新分配导致阵发性夜间呼吸困难，并导致中枢性睡眠呼吸暂停。12在这方面，使用曹等人的技术比较仰卧位较长时间后的水流的重力分布也将是有价值的。运动过程中血容量分布也可能发生变化，肺血流灌注分布也可能发生改变。因此，对锻炼效果的研究也是有价值的。由于肺血管收缩似乎在心力衰竭患者的肺血流再分布中起重要作用，CaO等人的技术可能提供一个强有力的工具来评估肺血管扩张剂西地那非对射血分数减少和保留的心力衰竭患者的益处机制。5、13、14综上所述，心力衰竭的许多临床表现都是由对肺的影响引起的。曹等人的新研究指出，创新的磁共振技术能够为心脏对肺的影响机制提供新的见解。
690 Circ Cardiovasc Imaging November 2012 there was a substantially greater perfusion of the dependent portions (ie, posterior) than the least dependent portion (anterior). Presumably, this reflects the additional hydrostatic pressure in the dependent portions of the lung. With HF, this gravitational gradient was blunted, being reduced in proportion to the left ventricular end-diastolic pressure. Thus, in HF, the perfusion to the dependent regions of the lung was reduced more than the flow to the anterior regions. In a multivariate analysis, this altered perfusion was most closely associated with elevated mean pulmonary artery pressure. This suggests that the redistribution against the hydrostatic gradient was because of pulmonary vasoconstriction that was more marked in the dependent portions of the lungs. Thus, there was a redistribution of flow to the less dependent portions of the lung. A similar cephalad redistribution of pulmonary flow seen on an upright chest x-ray is a classic finding of HF. Dyspnea in HF is worse after lying down (orthopnea). It is likely that the redistribution of flow in the supine position, so elegantly described by Cao et al, contributes to orthopnea. In addition, in HF, an expansion and central redistribution of blood volume from the periphery with prolonged time in the supine position results in paroxysmal nocturnal dyspnea and contributes to central sleep apnea. 12 In this regard, studies using the technique of Cao et al8 comparing the gravitational distribution of flow after a prolonged period in the supine position will also be valuable. There may also be shifts in the distribution of blood volume and alteration of the distribution of pulmonary perfusion during exercise. As such, studies of the effect of exercise would also be valuable. Because pulmonary vasoconstriction seems to play an important role in producing the redistribution of lung perfusion in patients with HF, the technique of Cao et al may provide a powerful tool to assess the mechanism of benefit of the pulmonary vasodilator, sildenafil, in patients with HF with both reduced and preserved ejection fractions. 5, 13, 14 In summary, many of the clinical manifestations of HF result from the impact on the lung. The new study of Cao et al8 points to the ability of innovative magnetic resonance techniques to provide new insight into the mechanisms of the heart’s impact on the lungs.