Hashimoto R, Yoshii S, Hosaka S, Suzuki S, Kato J, Tada Y
Second Department of Surgery, Yamanashi Medical University, Japan.
Kyobu Geka. 1995 Nov;48(12):997-1001.
We investigated the left ventricular (LV) systolic function and geometry in mitral valve replacement (MVR) with and without preservation of mitral apparatus. Five patients had conventional MVR without mitral annulus papillary muscle continuity (group C) and five patients had MVR with preservation of the continuity (group P). LV cineangiograms were assessed before and one month after surgery. LV volume was calculated by the method of Kennedy. Long axis dimension is defined as the distance between the apex and the center of mitral orifice in right anterior oblique projection. Short axis dimension is defined as the cross-sectional dimension at the middle point of the long axis. Paired Student's t tests were employed to compare the preoperative and postoperative data. LV ejection fraction decreased significantly from 69.4 +/- 9.5 to 51.8 +/- 10.5% in group C (p < 0.05) and did not change significantly in group P (from 51.6 +/- 19.9 to 56.8 +/- 12.9%). Fractional shortening of the long axis increased significantly from 15.0 +/- 11.8 to 21.2 +/- 14.0% in group P (p < 0.02) and did not change significantly in group C (from 16.5 +/- 8.6 to 13.1 +/- 3.3%). Ratio of LV end-systolic long axis to short axis dimension increased significantly from 1.76 +/- 0.31 to 2.12 +/- 0.21 in group C (p < 0.05) and did not change significantly in group P (from 1.90 +/- 0.22 to 1.95 +/- 0.22). We conclude that the ratio of systolic long to short axis increases, i.e., systolic LV shape changes to become longer and slender, and ejection fraction decreases after surgery in MVR without preservation of mitral apparatus. Conversely, preserving the mitral apparatus in MVR results in no significant change in systolic LV function and geometry, because of preserving fractional shortening of long axis.
我们研究了保留或不保留二尖瓣装置的二尖瓣置换术（MVR）中左心室（LV）的收缩功能和几何形态。5例患者接受了不保留二尖瓣环乳头肌连续性的传统MVR（C组），5例患者接受了保留连续性的MVR（P组）。在手术前和术后1个月评估左心室电影血管造影。左心室容积通过肯尼迪方法计算。长轴维度定义为右前斜位投影中的心尖与二尖瓣口中心之间的距离。短轴维度定义为长轴中点处的横截面维度。采用配对学生t检验比较术前和术后数据。C组左心室射血分数从69.4±9.5%显著下降至51.8±10.5%（p<0.05），而P组无显著变化（从51.6±19.9%至56.8±12.9%）。P组长轴缩短分数从15.0±11.8%显著增加至21.2±14.0%（p<0.02），C组无显著变化（从16.5±8.6%至13.1±3.3%）。C组左心室收缩末期长轴与短轴维度之比从1.76±0.31显著增加至2.12±0.21（p<0.05），P组无显著变化（从1.90±0.22至1.95±0.22）。我们得出结论，在不保留二尖瓣装置的MVR中，术后收缩期长轴与短轴之比增加，即收缩期左心室形状变为更长更细，射血分数降低。相反，在MVR中保留二尖瓣装置可使左心室收缩功能和几何形态无显著变化，这是因为保留了长轴缩短分数。
