Ventilatory and Diffusion Abnormalities in Potential Heart Transplant Recipients

Few data are available concerning pulmonary function in patients with severe chronic congestive heart failure. Of 315 patients evaluated for potential cardiac transplantation at UCLA, 132 underwent pulmonary function tests. The latter patients had severe heart failure with a mean left ventricular ejection fraction of 19 percent and mean cardiac index of 2.1 L/min/m2. Diffusion impairment either alone or combined with restrictive and/or obstructive ventilatory defects occured in 67 percent of the patients evaluated. Diffusion impairment occurred as the sole abnormality in 31 percent of the patients and in combination with a restrictive ventilatory defect in 21 percent. A reduction in diffusing capacity has not been previously described as a frequent finding in patients with chronic congestive heart failure. In contrast to other studies involving patients with acute heart failure, obstructive ventilatory defects were uncommon. None of the lung function abnormalities was associated with smoking status, prior drug use, chest roentgenographic changes, hemodynamic findings, or clinical features, including duration of congestive heart failure. The mechanism for the diffusion impairment is unclear but could be due to chronic passive congestion with pulmonary fibrosis and/or recurrent pulmonary emboli. Recognition of diffusion impairment as a common finding in patients with severe chronic congestive heart failure who are candidates for heart transplantation is important for proper interpretation of possible post-transplant changes in diffusing capacity due to other causes.

关于严重慢性充血性心力衰竭患者的肺功能，现有数据很少。在加州大学洛杉矶分校接受潜在心脏移植评估的315名患者中，132人进行了肺功能测试。这些患者患有严重心力衰竭，平均左心室射血分数为19%，平均心脏指数为2.1升/分钟/平方米。67%接受评估的患者出现单纯弥散障碍或合并限制性和/或阻塞性通气功能缺陷。31%的患者仅出现弥散障碍这一异常，21%的患者弥散障碍合并限制性通气功能缺陷。此前，弥散能力降低未被描述为慢性充血性心力衰竭患者的常见表现。与其他涉及急性心力衰竭患者的研究不同，阻塞性通气功能缺陷并不常见。任何肺功能异常都与吸烟状况、既往药物使用、胸部X线变化、血流动力学发现或临床特征（包括充血性心力衰竭的病程）无关。弥散障碍的机制尚不清楚，但可能是由于慢性被动性淤血伴肺纤维化和/或反复肺栓塞所致。认识到弥散障碍是严重慢性充血性心力衰竭且适合心脏移植患者的常见表现，对于正确解释因其他原因导致的移植后弥散能力可能发生的变化非常重要。