Zakai Saad Bader, Khan Salman-ur-Rehman, Rabbi Fazle, Tasneem Habiba
Department of Cardiac Surgery, National Institute of Cardiovascular Diseases (NICVD), Karachi, Pakistan.
J Ayub Med Coll Abbottabad. 2010 Jan-Mar;22(1):91-6.
Convention mitral valve (MV) replacement is known to cause deterioration in the left ventricle function, the major mechanism responsible being disruption of the annulo-papillary continuity, thus favoring preservation of the mitral subvalvular apparatus. The aim of this study was to compare the early and midterm results, in terms of cardiac mechanics and clinical outcomes, of preserving the subvalvular apparatus (partial/complete) verses resection during mitral valve replacement.
This was a prospective non randomised trial. One hundred and twenty-two patients (mean age 40.36 +/- 14.27 years) admitted for MV replacement from January 2009 to September 2009 were included in the study. They were divided into 3 groups: complete excision of the subvalvular apparatus (group 1 = 32); preservation of the posterior leaflet (group 2 = 54) and total chordal preservation (group 3 = 36). Echocardiography was done preoperatively, at discharge, and at 6 months follow-up.
The preservation groups 2, 3 revealed marked improvements with respect to the End-diestolic Volume (EDV) and End-Systolic Volume (ESV) as compared to the non-preservation group 1 at discharge from hospital. At followup, the preservation groups showed improved EDV and ESV in contrast to the non-preservation group, where the ventricular volumes had a declining pattern. Ejection fraction remained below the baseline preoperative level in all three groups at discharge from hospital. In the follow-up, chordal preservation groups showed significant improvements in the ejection fraction as compared to the resection group. An interesting finding was that of PA pressures and LA size between the groups. It was significantly improved in the preservation groups as compared to the resection group. At follow-up, 43.5% of patients in group 1 were in AF compared with 27.5% in group 2 and 21.4% in group 3. More patients in group 1 were in NYHA functional class III or IV at follow-up: 30.4% versus 7.5% and 7.1% respectively.
Preservation of the mitral subvalvular apparatus resulted in a greater decrease of ventricular dimensions at discharge which was maintained at follow-up; complete resection resulted in ventricular dilatation at follow-up. Furthermore, the ejection fraction improved in the preservation groups compared to the complete resection group which showed a decline at follow-up.
传统二尖瓣置换术会导致左心室功能恶化，主要机制是瓣环-乳头肌连续性中断，因此提倡保留二尖瓣瓣下结构。本研究旨在比较二尖瓣置换术中保留瓣下结构（部分/完全）与切除瓣下结构在心脏力学和临床结局方面的早期和中期结果。
这是一项前瞻性非随机试验。纳入2009年1月至2009年9月因二尖瓣置换术入院的122例患者（平均年龄40.36±14.27岁）。他们被分为3组：完全切除瓣下结构（第1组=32例）；保留后叶（第2组=54例）和完全保留腱索（第3组=36例）。术前、出院时及随访6个月时进行超声心动图检查。
与非保留组第1组相比，保留组第2、3组出院时舒张末期容积（EDV）和收缩末期容积（ESV）有显著改善。随访时，保留组EDV和ESV有所改善，而非保留组心室容积呈下降趋势。三组患者出院时射血分数均低于术前基线水平。随访时，与切除组相比，腱索保留组射血分数有显著改善。一个有趣的发现是各组之间肺动脉压力和左心房大小的情况。与切除组相比，保留组有显著改善。随访时，第1组43.5%的患者出现房颤，第2组为27.5%，第3组为21.4%。第1组更多患者随访时处于纽约心脏协会（NYHA）功能分级III或IV级：分别为30.4%、7.5%和7.1%。
保留二尖瓣瓣下结构在出院时导致心室尺寸更大程度减小，且在随访中得以维持；完全切除导致随访时心室扩张。此外，与完全切除组相比，保留组射血分数有所改善，完全切除组随访时射血分数下降。
