Yun K L, Sintek C F, Miller D C, Schuyler G T, Fletcher A D, Pfeffer T A, Kochamba G S, Khonsari S, Zile M R
Department of Cardiac Surgery, Kaiser Permanente Medical Center, Los Angeles, CA, USA.
Circulation. 1999 Nov 9;100(19 Suppl):II90-4. doi: 10.1161/01.cir.100.suppl_2.ii-90.
The merits of retaining the subvalvular apparatus during mitral valve replacement for chronic mitral regurgitation have been demonstrated in numerous clinical and laboratory investigations. In this preliminary report, we analyzed the early effects of complete versus partial chordal preservation on left ventricular mechanics.
Fifty patients undergoing isolated surgical correction of mitral insufficiency were prospectively randomized to either total or partial chordal-sparing mitral valve replacement. Of the first 19 patients studied, 8 had preservation of the posterior leaflet only, and 11 had complete preservation of all chordal structures. A comparison group consisted of 6 patients who had primary mitral valve repair. Echocardiography was performed preoperatively and at discharge from the hospital to determine dimensions, wall stress, and ejection fraction. Preservation of the posterior leaflet only resulted in a reduction in end-diastolic volume, an increase in end-systolic volume (P=0.058), a rising trend in end-systolic stress, a decrease in long-axis fractional shortening, and a fall in ejection fraction from 0.68+/-0.16 to 0. 46+/-0.19 (P=0.001). Although patients who had preservation of all chordal structures also had decreased end-diastolic volume, long-axis fractional shortening, and ejection fraction (0.60+/-0.13 to 0.52+/-0.07, P=0.01), end-systolic stress fell and end-systolic volume decreased instead of increased. Compared with the posterior leaflet preservation group, those in the group with completely preserved chordal structures had a larger decline in end-diastolic volume and smaller decreases in long-axis fractional shortening and ejection fraction. Changes in end-systolic volume and stress were also statistically different between the 2 cohorts. No differences were detected between the group with total preserved chordal structures and the mitral repair group in any of the measured parameters.
Compared with posterior chordal preservation only, complete retention of the subvalvular apparatus during mitral valve replacement resulted in improved ejection performance and smaller chamber volumes due to reduced systolic wall stress. These hemodynamic advantages are comparable to those observed with primary mitral reconstruction.
在众多临床和实验室研究中已证实，在二尖瓣置换治疗慢性二尖瓣反流时保留瓣下装置的优点。在本初步报告中，我们分析了完全保留与部分保留腱索对左心室力学的早期影响。
50例接受单纯二尖瓣反流手术矫正的患者被前瞻性随机分为完全保留腱索或部分保留腱索的二尖瓣置换组。在最初研究的19例患者中，8例仅保留后叶，11例保留所有腱索结构。一个对照组由6例接受初次二尖瓣修复的患者组成。术前及出院时进行超声心动图检查，以确定心室大小、壁应力和射血分数。仅保留后叶导致舒张末期容积减小，收缩末期容积增加（P = 0.058），收缩末期应力呈上升趋势，长轴缩短分数降低，射血分数从0.68±0.16降至0.46±0.19（P = 0.001）。尽管保留所有腱索结构患者的舒张末期容积、长轴缩短分数和射血分数也降低（从0.60±0.13降至0.52±0.07，P = 0.01），但收缩末期应力下降，收缩末期容积减小而非增加。与保留后叶组相比，完全保留腱索结构组的舒张末期容积下降幅度更大，长轴缩短分数和射血分数下降幅度更小。两组间收缩末期容积和应力的变化也有统计学差异。在任何测量参数方面，完全保留腱索结构组与二尖瓣修复组之间均未检测到差异。
与仅保留后腱索相比，二尖瓣置换时完全保留瓣下装置可改善射血功能，由于收缩期壁应力降低，心室容积减小。这些血流动力学优势与初次二尖瓣重建相当。
