Chambers J, Cross J, Deverall P, Sowton E
Department of Cardiology, Guy's Hospital, London, England.
J Am Coll Cardiol. 1993 Feb;21(2):398-405. doi: 10.1016/0735-1097(93)90681-p.
The aim of this study was to describe the echocardiographic appearance of the normal CarboMedics prosthesis in the aortic and mitral positions.
Echocardiography is the standard method of assessing prosthetic valves. However, new valve designs may still be marketed without an accompanying echocardiographic description. The CarboMedics prosthesis is in widespread use, but few noninvasive hemodynamic data have been published.
Echocardiography was performed in 147 patients with a total of 96 normally functioning CarboMedics prostheses in the aortic position and 75 in the mitral position; in 24 patients, valves were implanted in both positions. The following variables were measured: peak and mean transvalvular velocities, peak and mean instantaneous gradient estimated from the modified Bernoulli equation, aortic acceleration slope, pressure half-time, transvalvular flow and effective orifice area using the continuity equation. Patterns of regurgitation were observed by transthoracic study in all valves and by transesophageal study in selected mitral valve prostheses.
For the aortic valve prostheses, estimated mean gradient ranged between 6 and 19 mm Hg. Effective area differed markedly among the anulus diameters (p < 0.001), with a mean value of 1 cm2 for the 19-mm valve and 2.6 cm2 for the 29-mm valve. For the mitral valve prostheses, mean gradient ranged from 3 to 7 mm Hg. There were a total of four washing leaks, one on either side of each pivotal point, and these lasted throughout systole or diastole. One jet was commonly more prominent than the other three.
The CarboMedics prosthesis offered relatively little resistance to forward flow except at small anulus diameters. The washing jets were prominent and would be easy to misdiagnose as a sign of paraprosthetic regurgitation.
本研究旨在描述正常的CarboMedics人工瓣膜在主动脉和二尖瓣位置的超声心动图表现。
超声心动图是评估人工瓣膜的标准方法。然而，新的瓣膜设计在上市时可能仍未附带超声心动图描述。CarboMedics人工瓣膜已广泛使用，但很少有非侵入性血流动力学数据发表。
对147例患者进行了超声心动图检查，这些患者共有96个在主动脉位置功能正常的CarboMedics人工瓣膜和75个在二尖瓣位置的人工瓣膜；24例患者在两个位置都植入了瓣膜。测量了以下变量：跨瓣峰值和平均速度、根据改良伯努利方程估算的峰值和平均瞬时压差、主动脉加速度斜率、压力减半时间、跨瓣血流以及使用连续方程计算的有效瓣口面积。通过经胸研究观察所有瓣膜的反流模式，通过经食管研究观察选定二尖瓣人工瓣膜的反流模式。
对于主动脉瓣人工瓣膜，估算的平均压差在6至19 mmHg之间。有效面积在瓣环直径之间存在显著差异（p < 0.001），19毫米瓣膜的平均值为1平方厘米，29毫米瓣膜的平均值为2.6平方厘米。对于二尖瓣人工瓣膜，平均压差范围为3至7 mmHg。共有四处冲洗性漏血，每个枢轴点两侧各一处，这些漏血在整个收缩期或舒张期持续存在。一个喷射通常比其他三个更明显。
除了瓣环直径较小时，CarboMedics人工瓣膜对正向血流的阻力相对较小。冲洗性喷射明显，容易被误诊为人工瓣周反流的迹象。
