主动脉瓣狭窄为主联合瓣膜病左心室病理改变与术后恢复的关系

Relationship between pathologic features and left ventricular function recovery in patients with predominate aortic valve stenosis undergoing aortic plus mitral valve replacement

目的探讨风湿性心脏病主动脉瓣狭窄为主双瓣膜置换手术患者左心室心肌病理改变和手术后恢复的关系。方法本组患者32例，采用超声心动图对比分析手术前、术后3、6、12个月左心室舒张末内径（left ventricular end—diastolic diameter，LVEDD），左心室射血分数（ejection fraction，EF）、短轴缩短率（fractional shortening，FS），主动脉瓣跨瓣压差（pressure gradient，PG），室间隔厚度（interventricular septal，IVS），左心室后壁厚度（left ventricular posterior wall thickness，LVPW），左心室重量指数（left ventricular mass index，LVMI）等，评估心脏功能恢复情况。术中取患者二尖瓣乳头肌作Massion病理染色，应用多媒体彩色病理图文分析系统测量心肌胶原纤维含量，并与意外死亡成年人乳头肌进行比较。结果无手术早期死亡，均痊愈出院。手术后随访10～20个月，恢复良好，心脏超声结果显示，PG较术前明显降低（P〈0．01），LVEDD和LVMI也有降低（P〈0．05）；EF、FS较术前有改善（P〈0．05），IVS和LVPW与术前比较无差异（P〉0．05）。病理结果显示，手术组左心室心肌肥厚明显，心肌细胞肥大，心肌细胞可见空泡样变，Masson染色显示心肌细胞间质胶原纤维增生明显。定量分析手术组左心室肌间质胶原纤维容积比为（18．11±4．32）％，血管周围胶原纤维面积比例为（1．42±0．80）％，正常组分别为（6．31±1．69）％和（0．87±0．31）％，差异均明显（P〈0．05）。结论胶原成分异常沉积所致心肌纤维化是本组风心病主动脉瓣狭窄为主双瓣膜置换手术患者心肌的主要病理改变之一。术后经心脏超声评估心脏功能有改善，但仍不十分满意，可能与左心室心肌纤维化严重有关。

Objective To analyze pathologic features of left ventricular myocardium in rheumatic heart disease patients with predominate aortic valve stenosis, and observe their left ventricular function recovery after aortic plus mitral valve replacement. Methods Thirty-two rheumatic heart disease patients with predominate aortic valve stenosis underwent aortic plus mitral valve replacement. Echocardiography was used to evaluate the left ventricular function before operation, 3 months, 6 months and 12 months after operation. Left ventricular end-diastolic diameter （LVEDD）, ejection fraction （EF）, fractional shortening （FS） and pressure gradient （PG） of aortic valve, interventricular septal thickness （ IVST）, left ventricular posterior wall thickness （ LVPWT）, left ventricular mass index （LVMI） were observed. Meanwhile, mitral papillary muscle samples were obtained during operation. Histological features were studied by using Massion staining, and collagenous contents were quantitated with a computer-assisted imaging analysis system, comparing with control samples obtained from 4 accidently died adults. Results All 32 patients were discharged without death or complications. There was no death during 10 to 20 months follow-up. The echocardiographic follow-up demonstrated that aortic valve PG significantly decreased （ P 〈 0.01 ）, LVEDD and LVMI decreased （ P 〈 0.05 ） , EF and FS improved （P 〈 0. 05 ） after surgery, while no statistic change was found in IVS and LVPW. Pathologic examination revealed significant myocardial hypertrophy in left ventricle, with vesicles in hypertrophied cardiomyocytes. Significant collagen fibroplasia in myocardial interstitium was observed with Masson＇s staining. Comparing with the control group, left ventricular myocardial collagen volume fraction （CVF） and perivascular circumferential area （PVCA） increased significantly （ P 〈 0.05 ）, （ 18.11±4.32） % vs （6.31 ± 1.69） % for CVF, and （ 1. 42 ± 0.80） % vs （0.87 ± 0.71 ） % for PVCA. Conclusion Myocardial fibrosis caused by abnormal collagen accumulation was one of the main characteristics of myocardial tissue observed with Masson＇s staining. Left ventricular function was improved after aortic plus mitral valve replacement in rheumatic heart disease patients with predominate aortic valve stenosis. Significant myocardial fibrosis may be one of the reasons obstructing left ventricular functional recovery.