From the Department of Radiology and Research Institute of Radiology, Cardiac Imaging Center (K.H., D.H.Y., S.Y.S., N.K., J.W.K., T.H.L.), Department of Cardiology, Cardiac Imaging Center (D. H. Kim, J.M.S., D. H. Kang, J.K.S.), and Department of Cardiothoracic Surgery (J.B.K., S.H.J., S.J.C., C.H.C., J.W.L.), Asan Medical Center, University of Ulsan College of Medicine, Asanbyeongwon-gil 86, Seoul 138-736, South Korea; and the Department of Radiology, KyungHee University Medical Center, KyungHee University, Seoul, Korea (S.Y.S).
Radiology. 2015 Sep;276(3):724-31. doi: 10.1148/radiol.2015142400. Epub 2015 Apr 22.
To investigate the cardiac computed tomographic (CT) findings and clinical implications of subprosthetic pannus in patients who have undergone aortic valve replacement.
The institutional review board approved this retrospective study, and the need to obtain written informed consent was waived. From April 2011 to March 2012, 88 patients (mean age, 63 years; 45 men) with a prosthetic aortic valve who underwent cardiac CT were retrospectively selected. Dynamic cardiac CT images were analyzed by using a multiplanar reformatted technique. The presence or absence of subprosthetic pannus and its extent were evaluated at cardiac CT. The geometric orifice area and the effective orifice area of each prosthetic valve were measured to enable analysis of the pannus encroachment ratio in the systolic phase. Hemodynamic parameters at echocardiography, including mean transprosthetic pressure gradient (MTPG), were compared between patients with and those without pannus. The encroachment ratio and the MTPG were correlated by using the Spearman test to evaluate the relationship between the two variables.
Seventeen patients (19%) had subprosthetic pannus at cardiac CT. In patients with subprosthetic pannus, MTPG, peak pressure gradient, transvalvular peak velocity, and left ventricular ejection fraction (LVEF) were significantly higher than in patients without pannus (MTPG: 28.1 mm Hg ± 19.8 [standard deviation] vs 14.0 mm Hg ± 6.5, P = .004; peak pressure gradient: 53.1 mm Hg ± 38.4 vs 26.1 mm Hg ± 11.4, P = .004; transvalvular peak velocity: 3.3 m/sec ± 1.3 vs 2.5 m/sec ± 0.5; and LVEF: 64.7% ± 7.4 vs 56.8% ± 10.5, P = .004). A high MTPG (≥40 mm Hg) was observed in four patients at echocardiography, and subprosthetic panni were identified at CT in all four patients. In patients with increased MTPGs, the encroachment ratio by subprosthetic pannus at CT was significantly higher than that in patients with MTPGs of less than 40 mm Hg (42.7 ± 13.3 vs 7.6 ± 3, P = .012).
Cardiac CT revealed subprosthetic pannus to be a cause of the hemodynamic changes in patients who had undergone aortic valve replacement. By helping quantify the encroachment ratio by pannus, cardiac CT may help differentiate which subprosthetic panni might lead to substantial flow limitation over the prosthetic aortic valve.
探讨主动脉瓣置换术后患者瓣下赘生物的心脏 CT 表现及其临床意义。
本研究经机构审查委员会批准，且豁免了书面知情同意书的要求。回顾性选取 2011 年 4 月至 2012 年 3 月间 88 例行心脏 CT 检查的主动脉瓣置换术后患者，患者平均年龄 63 岁（45 名男性）。采用多平面重建技术分析动态心脏 CT 图像。在心脏 CT 上评估瓣下赘生物的有无及其范围。测量每个人工瓣膜的几何开口面积和有效开口面积，以分析收缩期赘生物的侵犯率。比较超声心动图检查的血流动力学参数，包括平均跨瓣压力梯度（MTPG），比较有和无赘生物的患者间的参数差异。采用 Spearman 检验分析两者之间的相关性，以评估两种变量之间的关系。
17 例患者（19%）在心脏 CT 上发现瓣下赘生物。有瓣下赘生物的患者的 MTPG、峰值压力梯度、跨瓣峰值流速和左心室射血分数（LVEF）均明显高于无赘生物的患者（MTPG：28.1mmHg±19.8[标准差] vs. 14.0mmHg±6.5，P=0.004；峰值压力梯度：53.1mmHg±38.4 vs. 26.1mmHg±11.4，P=0.004；跨瓣峰值流速：3.3m/sec±1.3 vs. 2.5m/sec±0.5；LVEF：64.7%±7.4 vs. 56.8%±10.5，P=0.004）。超声心动图检查发现 4 例患者的 MTPG 较高（≥40mmHg），这 4 例患者的 CT 均显示瓣下赘生物。在 MTPG 升高的患者中，瓣下赘生物侵犯率明显高于 MTPG＜40mmHg 的患者（42.7±13.3 vs. 7.6±3，P=0.012）。
心脏 CT 显示瓣下赘生物是主动脉瓣置换术后患者血流动力学改变的原因。通过定量分析赘生物的侵犯率，心脏 CT 有助于区分哪些瓣下赘生物可能会导致主动脉瓣人工瓣膜的显著血流受限。
