主动脉瓣环扩大术在主动脉瓣置换术中的应用

目的 总结主动脉瓣置换术中处理小主动脉瓣环的体会.方法 我院在2000年至2010年期间收治主动脉瓣环细小的主动脉瓣病变18例,均采取改良Manouguian方法扩大主动脉瓣环,再置入较合适的机械主动脉瓣.同期行二尖瓣置换6例,室间隔修补1例,三尖瓣成形5例.结果 17例有效开口面积指数(EOAI)均达到0.85cm2/m2以上,1例0.80cm2/m2.术后严重低心排综合征1例,室性心律失常3例,心脏压塞1例.18例痊愈出院,随访1～10年,术后6个月复查发现EOAI为0.80cm2/m2的患者主动脉跨瓣压差较高,室间隔及左室壁厚度恢复较慢,左室射血分数较低;而比值在0.85～1.0之间与大于1.0的患者相比,主动脉跨瓣压差、室间隔及左室壁厚度平均值稍高,但差异无统计学意义.2例术后6年因身高、体重增加EOAI分别下降到0.79、0.81cm2/m2,出现活动后心慌,心电图提示左室高电压,经扩管等药物治疗和一般处理,症状明显改善.结论 改良Manouguian方法扩大主动脉瓣环安全、有效,可置入合适的机械主动脉瓣,有利于提高手术疗效.     

The dynamic anterior mitral annulus

Background

The anterior mitral annulus is considered a fixed structure. Recent data suggest otherwise. This study tested the hypothesis that the size of the anterior annulus varies with hemodynamic loading and ventricular contractility.

Methods

Sonomicrometry array localization measured annular area, total annular circumference, anterior circumference, and posterior circumference in 6 sheep before and after neosynephrine increased systolic blood pressure by at least 150% during atrial pacing at 120 beats/min. In 6 additional animals the same dimensions were measured during atrial pacing (at 120 and 150 beats/min) and during isoproteronol infusions to increase heart rate to 120 and 150 beats/min.

Results

Neosynephrine increased systolic total annular circumference from 99.7 ± 5.5 mm to 106.9 ± 9.6 mm. Anterior circumference increased from 40.8 ± 4.0 mm to 45.3 ± 5.7 mm whereas posterior circumference only increased from 59.0 ± 5.5 mm to 61.6 ± 7.0 mm. Low isoproteronol infusion decreased systolic total annular circumference from 107.5 ± 8.3 mm to 101.9 ± 10.6 mm. Most of this change occurred in the posterior circumference. Higher infusions of isoproteronol decreased total annular circumference from 106.8 ± 8.3 mm to 98.3 ± 9.7 mm. At this higher inotropic state the decrease in annular size was similar in the anterior and posterior annulus.

Conclusions

In sheep, the anterior annulus is a dynamic structure that varies in size in response to changes in hemodynamic loading and ventricular contractility.     

脱细胞纤维环基质对兔纤维环源干细胞分化的影响

目的观察脱细胞纤维环基质(DAFM)对纤维环源干细胞(AFSC)分化行为的影响,为新型纤维环组织工程支架材料的开发提供依据。方法将从新西兰大白兔获得的AFSC接种于由猪纤维环组织制备的DAFM膜和无DAFM膜培养皿,分别进行成脂、成骨、成软骨分化诱导,考察DAFM对AFSC分化行为的影响。结果 AFSC在DAFM膜上生长良好。DAFM膜上AFSC成脂、成软骨诱导分化水平低于无DAFM膜者,而成骨诱导分化水平显著高于无DAFM膜者;DAFM膜上的成脂、成骨及成软骨诱导比值(诱导组基因表达量/对照组基因表达量)均高于无DAFM膜者。结论猪DAFM有利于促进兔AFSC成骨分化,抑制其成脂及成软骨分化,较好地维持AFSC的差异性分化潜能。     

Calcification of the mitral annulus.

Successful valve replacement has been achieved within the first three years in two patients who had extensive calcification of the mitral valve annulus. This condition, although commonly reported in pathology and autopsy studies, has been rare in our clinical experience. Surgical management does not appear to us to have been reported previously. It was regarded in our earlier experience as a deterrent to mitral valve surgery. Certain technical factors which contributed to success are emphasized in the two cases described in this report.     

Tensile properties of the annulus fibrosus

Summary Part I of this study showed that collagen fibres do need not need to be continuous to reinforce the annulus fibrosus, and that 15-mm-wide samples of annulus retain about 44% of their in situ stiffness and strength when stretched vertically. Part II investigated the ultimate tensile strength (UTS) and fatigue life of such samples. Vertical slices, 5 mm thick and 30 mm wide, were cut from the anterior and posterior margins of the annulus and adjacent vertebral bodies. Each slice was divided sagittally to obtain a matched pair of specimens. The bony ends of each specimen were secured in a materials testing machine so that the annulus could be stretched vertically, as occurs during bending movements of the spine in life. One of each pair of specimens was stretched to failure to obtain its UTS; the other was cyclically loaded at some fraction of the UTS until failure occurred. Tensile failure started with the hyaline cartilage end-plate being stripped off the underlying bone and ended with the most peripheral annular fibres pulling out of the matrix. The estimated in situ strength in the vertical direction was 3.9 MPa for the anterior annulus and 8.6 MPa for the posterior annulus. Fatigue failure could occur in less than 10000 cycles if the tensile force exceeded 45% of the UTS. The results explain why radial fissures often fail to penetrate the peripheral annulus. When compared with in vivo measurements of spinal loading, they suggest that repetitive forward bending movements could cause fatigue failure of the posterior annulus.     

Patch closure of aortic annulus mycotic aneurysms

Twenty-three patients with bacterial endocarditis and mycotic aneurysms of the aortic annulus were treated between 1978 and 1985. There were 18 men and 5 women ranging from 24 to 72 years old. All patients had congestive heart failure and positive blood cultures as a complication of the endocarditis and were in New York Heart Association (NYHA) Functional Class III or IV. The aneurysm complicated late prosthetic valve endocarditis in 7 patients and native valve endocarditis in 16. The most common infecting organisms were streptococci (12 patients) and staphylococci (7 patients). The noncoronary sinus was the most frequent site for aneurysm formation. Following debridement of the abscess cavity, the orifice of the aneurysm was closed with a patch of Dacron in 20 patients and autologous pericardium in 3. A prosthetic valve (18 bioprosthetic and 5 mechanical) was secured to the noninfected portion of the native annulus and to the patch at the level of annulus. There were 3 deaths, 1 perioperative and 2 late, each without evidence of residual infection or aortic insufficiency. There are 20 late survivors (87%). After a mean follow-up of 1 year, all patients are in NYHA Functional Class I. Patch closure of mycotic aneurysms involving the aortic annulus permits aggressive debridement of the abscess cavity and affords closure of the orifice without tension. The prosthetic valve can be seated at the level of the native annulus, thus avoiding complicated reconstructive procedures of the aortic root and coronary arteries. This technique is an effective alternative in selected cases of mycotic aneurysms involving the aortic annulus.     

Transseptal control of the difficult aortic annulus

Successful control of the aortic root in extensive erosive endocarditis, with or without mycotic ventricular septal defect, frequently depends on secure prosthetic fixation to the interventricular septum. We describe transseptal suture fixation of aortic root prostheses through a pulmonary infundibular approach and recommend its early use to avoid difficult, often injurious, attempts at septal suture from within the left ventricular outflow tract.     

瓣环结构重建的瓣膜置换手术

目的 总结瓣环结构重建的瓣膜置换手术技术及临床效果.方法 2003年1月至2009年5月59例病人行瓣环结构重建的瓣膜置换手术,其中细小主动脉根部43例,感染性心内膜炎累及瓣环结构13例,钙化性主动脉瓣病变钙化斑累及主动脉瓣环2例,主动脉瓣二尖瓣置换手术后主动脉根部出血1例.行主动脉瓣环重建加主动脉瓣置换术40例,二尖瓣瓣环重建二尖瓣置换术7例,主动脉-二尖瓣纤维环重建加主动脉二尖瓣置换术12例.结果 二尖瓣瓣环重建加二尖瓣置换手术与常规二尖瓣置换手术的主动脉阻断时间差异无统计学意义;而主动脉瓣瓣环重建加主动脉瓣置换以及二尖瓣-主动脉瓣纤维连接重建加二尖瓣主动脉瓣置换手术的主动脉阻断时间均明显延长.本组术后早期死亡4例,占6.7%.术后再次开胸止血2例,Ⅲ度房室传导阻滞2例,呼吸功能不全2例,急性肾功能衰竭2例.术后6个月复查超声心动图,无瓣周漏.结论 瓣环结构重建手术适合于瓣环过小需置人与体表面积相匹配的人工瓣膜、瓣膜病变累及瓣环结构的完整性或手术损伤等情况,尽管其手术操作较为复杂,主动脉阻断和体外循环时问均有所延长,但手术操作引起死亡的比率并未增加.

Abstract：

Objective To investigate the surgical technique and clinical outcomes of reconstruction of the annulus and the intervalvular fibrous body during valve replacements. Methods Fifty-nine patients underwent reconstruction of the annulus or the intervalvular fibrous body during the valve replacement. Indications for the operation were small aortic annulus which may cause patient/prosthesis mismatch in 43, active infective endocarditis with the abscess in the periannulus tissue in 13, extensive calcification of the aortic annulus in 2 and an active bleeding complication of the aortic root after aortic and mitral valve replacement in 1. The reconstruction was done with fresh autologous pericardium. Results The aortic clamping time in reconstruction of the intervalvular fibrous body with double valve replacement was longer than that of the regular double valve replacement. Four patients died in the perioperative period, giving an overall in- hospital mortality of 6.7%. Postoperative complication were: re-sternotomy for bleeding in 2, Ⅲ degree A-V block in 2, respiratory dysfunction in 2, and acute renal failure in 2. Patients were followed up for 6 months by echocardiography study, and no periannular leakage was found. Conclusion Reconstruction of the annulus is an effective technique for patients with a small aortic annulus, extensive calcification of the interventricular fibrous body and active infective endocarditis with abscess. Although the operative procedure is challenging and taking more time, the technique is safe and reproducible.     

Calcified mitral valve annulus: prosthesis insertion

We describe a technique for insertion of a mitral valve prosthesis in the presence of a heavily calcified annulus. The valve leaflets are used for securing the prosthesis, and both the anterior and posterior chordae tendineae and papillary muscle complexes are preserved.     

人工生物膜修复椎间盘纤维环的研究

目的 用不同方法处理椎间盘纤维环,观察人工生物膜对椎间盘纤维环缺损的修复作用.方法 成年山羊8只,雌雄各4只,对每只羊的腰椎(腰2/3、腰3/4、腰4/5)椎间盘纤维环进行随机处理,处理方法包括:(1)暴露出椎间盘纤维环,不作任何处理;(2)暴露出椎间盘纤维环后,将其切开,用人下生物膜填充缺口;(3)暴露出椎间盘纤维环,尖刀将其切开,作为对照组.12周后,通过生物力学测试、核磁共振(MRI)及脱钙病理切片染色观察椎间盘纤维环的修复效果.结果 12周后,测试纤维环承受最大压力,单纯暴露组为(4.92±0.17)MPa,纤维环单纯切开组为(2.48±0.39)MPa,人工生物膜修复组为(3.76±1.56)MPa.人工生物膜修复组与单纯切开组,椎间盘纤维环完整性及生物强度均不如单纯暴露组,人工生物膜修复组优于单纯切开组,两组间的差异有统计学意义(P＜0.05),人工生物膜可与椎间盘纤维环的胶原纤维良好融合.结论 人工生物膜可对椎间盘纤维环缺口起到修复作用,能使其生物力学强度平均恢复76.4%,人工生物膜可以促进椎间盘结构完整性的恢复.     

Aortic valve replacement for the small aortic annulus

Aortic valve surgery for the small aortic annulus is still challenging for surgeons. Recently, the new types of high performance prosthesis have been developed and the chance of an aortic root enlargement (ARE) is decreasing. In this study, we propose the ideal strategy of the aortic surgery for the small aortic annulus. We analyzed the clinical records of 158 patients who underwent aortic valve replacement from August 1999 to October 2005 in our institution. The small aortic annulus was observed in 38 patients (24%). Fourteen patients of this group underwent ARE. Patient-prosthesis mismatch (PPM) was less frequently observed in patients with ARE compared to those without ARE. The additional time required for ARE was not considerable, and neither ischemic time nor cardiopulmonary bypass time was significantly prolonged by ARE. In conclusion, we have to select a prosthesis with sufficient orifice area to avoid PPM, otherwise we should choose an option of ARE. For this consideration, we definitely need the chart that demonstrates the relationship between the nominal size of various types of prostheses and the size of a patient's annulus that those prostheses actually fit.