芬太尼延迟性预处理对体外循环下心脏瓣膜置换术的心肌保护作用

目的:观察术前给予芬太尼对全麻体外循环下行心脏瓣膜置换术患者心肌的保护作用。方法:择期在全麻体外循环下行心脏瓣膜置换术患者共60例,心功能Ⅱ～Ⅲ级(NYHA标准)。随机被分为芬太尼预处理组和对照组:芬太尼预处理组术前2d给予0.3μg/kg.h芬太尼泵微量持续注射,分别在术前,主动脉开放1h、6h、12h、24h、48h采集血标本,测定肌钙蛋白I(cTnI)水平;并记录术中体外循环时间、主动脉阻闭时间、停跳液量、复跳方式、ICU停留时间等指标以及计算在ICU停留期间正性肌力药物得分。结果:芬太尼组血清cTnI整体升高水平低于对照组,其中在主动脉钳夹开放后6h、12h、24h与对照组相比有显著差异(P均0.05);芬太尼组在ICU停留的时间显著少于对照组(P0.05);在进入ICU后12h、24h、48h的正性肌力药物使用得分显著低于对照组(P均0.05)。结论:术前给予阿片受体激动剂芬太尼的延迟预处理对全麻体外循环下行心脏瓣膜置换术的患者具有心肌保护作用。     

非体外循环下冠状动脉搭桥术的麻醉管理

目的 :总结 2 8例非体外循环下多支冠状动脉搭桥术的麻醉管理。方法 :术前依据患者心脏功能及全身状况 ,给予营养心肌、扩冠、降压、利尿等治疗。采用静吸复合麻醉 ,气管插管控制呼吸 ,在非体外循环下行冠状动脉搭桥术。结果 :手术期间 4例血压过低 ,2例 ST段显著抬高伴室性心律失常 ,改为体外循环辅助下手术 ,余 2 2例术中血流动力学平稳。术毕非体外循环组 2 2例 6～ 8h内拔管 ,明显少于体外循环组 （10～ 16h）。 2 8例预后良好 ,无麻醉并发症。结论 :维持血流动力学平稳和心肌氧供需平衡 ,是非体外循环下冠状动脉搭桥术麻醉的关键     

舒芬太尼预处理对冠脉旁路移植术围术期认知功能和心肌保护的作用

目的:观察术前舒芬太尼延迟性预处理对体外循环下冠状动脉旁路移植术(CABG)围术期认知功能和心肌的保护作用。方法:选择择期在体外循环下行CABG的患者60例,随机均分为舒芬太尼预处理组(舒芬太尼组)和常规治疗对照组(对照组),分别在术前、主动脉开放1h、6h、12h、24h、48h采集血标本,测定心肌肌钙蛋白I(cTnI)水平,并在术前,术后7d接受神经心理(POCD)评价。结果:舒芬太尼组血清cTnI水平在主动脉开放后1h到术后48h均明显低于对照组[1h:(14.96±2.13)ng/ml比(23.66±3.15)ng/ml],P均0.05;两组在进入ICU后12h、24h、48h的正性肌力药物使用得分舒芬太尼组明显低于对照组[12h:(6.4±0.6)分比(8.4±0.6)分],P均0.05;舒芬太尼组术后认知功能障碍(POCD)发生率明显低于对照组(13.3%比30.0%,P=0.041)。结论:舒芬太尼的延迟预处理对体外循环下冠状动脉旁路移植术患者有心肌保护效应,同时可降低认知功能障碍的发生率,具有一定的脑保护作用。     

197例同期行心脏瓣膜手术、冠状动脉搭桥术患者的体外循环管理

目的 总结同期行心脏瓣膜手术、冠状动脉搭桥术患者的体外循环管理经验.方法 197例心脏瓣膜病合并冠心病患者,行心脏瓣膜置换术（或成形术）,同期行冠状动脉搭桥术.术中采用恰当的体外循环灌注方法;心肌保护采用4：1冷含血停搏液,应用单纯顺灌、顺灌联合逆灌、顺灌联合桥灌、顺逆灌联合桥灌技术.结果 术中转流平稳,患者血流动力学稳定,手术顺利.结论 良好的心肌保护和合理的体外循环灌注是心脏瓣膜手术同期行冠状动脉搭桥术手术成功的关键.     

非体外循环下冠状动脉搭桥术的麻醉管理

目的　总结 2 2例非体外循环下多支冠状动脉搭桥术的麻醉管理。方法　术前依据患者心脏功能及全身状贶 ,给予营养心肌、扩冠、控制心率与降压、利尿等治疗。采用静吸复合麻醉 ,气管插管控制呼吸 ,在非体外循环下行冠状动脉搭桥术。结果　手术期间 4例血压过低 ,其中 2例ST段显著抬高伴室性心律失常 ,改为体外循环辅助下手术 ,其余 2 0例术中血流动力学平稳。术毕非体外循环组 2 0例 6～ 8h拔管 ,明显少于体外循环组 ( 1 0 5h～ 1 5h)。全组病例预后良好 ,无麻醉并发症。结论　维持血流动力学平稳和心肌氧供需平衡 ,是非体外循环下冠状动脉搭桥麻醉的关键。     

高龄患者非体外循环下行冠状动脉搭桥术的麻醉管理

目的 :高龄冠心病患者行冠状动脉搭桥术 ,由于常伴有多个重要脏器功能减退 ,增加了冠状动脉搭桥围术期的危险因素 ,总结本组麻醉成功的经验。方法 :回顾性分析 6 8例 75～ 84岁行冠状动脉搭桥术的麻醉管理。术前多脏器功能检查 ,伴随疾病的治疗 ,麻醉用药选择 ,心血管正性肌力药和血管扩张药的选择 ,为高龄冠心病患者行冠状动脉搭桥围术期的治疗提供经验。结果 :6 5例顺利完成非体外循环下冠状动脉搭桥术。 3例在手术中发生室颤 ,经抢救在体外循环下行搭桥成功。术后 7d内死亡4例 ;肺部感染 3例 ,并行气管切开 ;脑栓塞 2例 ;全组无麻醉死亡。结论 :非体外循环下行冠状动脉搭桥术对患者全身生理干扰轻 ,术后恢复快、费用低 ,为高龄冠心病伴有重要脏器功能减退的患者开辟了新的治疗途径     

磷酸肌酸钠对老年全麻患者术后认知功能的影响

目的 通过简易智能状态检查法(MMSE)行神经心理学测试,观察磷酸肌酸钠对老年全麻患者术后认知功能的影响.方法 选择老年全麻腹部手术患者60例,随机分为试验组即磷酸肌酸钠组(30例)和对照组(30例).在全麻插管后试验组静点磷酸肌酸钠2 g,对照组静点等容积生理盐水,两组麻醉诱导方法及维持用药相同.于麻醉前和术后3h、1d、2d时分别记录MMSE评分.结果 MMSE评分在两组术后3h、1d、2d时均较术前明显降低(均P＜0.05),但实验组评分在术后3 h、1d、2d时均明显高于对照组(均P＜0.05).实验组术后3h、1d、2d时术后认知功能障碍(POCD)的发生率较对照组均降低(均P＜0.05).结论 老年全麻患者术中应用磷酸肌酸钠能提高术后认知功能,降低POCD的发生率.     

老年胃肠肿瘤根治术患者全麻术后早期认知功能障碍的危险因素

目的探讨老年胃肠肿瘤根治术患者全麻术后早期认知功能障碍的危险因素。方法 286例择期全麻下行胃肠肿瘤根治术老年患者。分别于手术前1 d、手术后1、3、7 d时经简易智能量表(MMSE)评分,术后评分低于术前1分以上确定有认知功能下降,则诊断为发生术后认知功能障碍(POCD)。对患者的术前、术中及术后一般情况各指标进行单因素分析,筛选出早期POCD的可能危险因素。结果 286例老年胃肠肿瘤根治术患者术后1 d POCD发生率为26.2%(75例),术后3 d发生率为23.8%(68例),术后7 d发生率为8.4%(24例);单因素分析结果表明年龄、受教育程度、术前合并高血压、糖尿病、脑梗死或冠心病、术中出现低血压、术后电解质紊乱及住院时间与POCD的发生有关(P0.05)。Logistic多因素回归分析表明年龄、受教育程度、术前合并高血压或糖尿病、术中低血压及住院时间是POCD的独立危险因素(P0.05)。结论年龄、受教育程度、术前合并高血压或糖尿病、术中低血压及住院时间是老年胃肠肿瘤根治术患者全麻术后早期认知功能障碍的独立危险因素。     

体外循环心脏瓣膜置换术老年患者血浆谷氨酸和γ-氨基丁酸水平与术后认知障碍的关系

目的探讨体外循环(CPB)心脏瓣膜置换术老年患者血浆谷氨酸(Glu)和γ-氨基丁酸(GABA)水平的变化与术后认知障碍(POCD)发生的关系。方法择期CPB下心脏瓣膜置换术老年患者60例均在静吸复合麻醉中成功实施了手术。分别于麻醉诱导前(T0)、手术结束时(T1)、术后24 h(T2)、48 h(T3)和72 h(T4)时取颈内静脉球部血样,采用反相高效液相色谱荧光方法(RP-HPLC)检测血浆Glu和GABA水平。采用简易智力状态检查(MMSE)于术前1 d、术后1、2、3 d评估所有患者认知功能。术后根据MMSE评分分为正常组(N组)、认知功能障碍组(POCD组)。结果术后3 d,22例(37%)发生POCD。与T0比较,T1～T3各时点POCD组血浆Glu、GABA浓度显著升高(P0. 01),T4时恢复;与N组比较,T1～T3各时点POCD组血浆Glu、GABAA浓度显著升高(P0. 01)。POCD组血浆Glu、GABA浓度与MMSE评分均呈显著负相关(r分别为-0. 97、-0. 87,P均0. 01)。结论 CPB心脏瓣膜置换术老年患者围术期血浆Glu、GABA水平升高可能与POCD发病有关。     

非体外循环下冠状动脉搭桥术的临床应用

目的 总结东莞市人民医院心胸外科2002年2月到2002年8月期间所行8例非体外循环冠状动脉搭桥术(OPCAB)患的临床资料，分析OPCAB手术的优点及疗效。方法 本组8例患，年龄32．65岁，术前心功能Ⅱ-Ⅲ级，左室射血分数49。58％，所有患均在非体外循环、心脏跳动状态下行冠状动脉搭桥术。结果 手术患无一例死亡，术后心绞痛症状均消失，心功能得到不同程度改善。结论 非体外循环冠状动脉搭桥术是一种安全可行、效果良好的冠心病治疗方法。     

重组人促红细胞生成素对瓣膜置换术患者心肌保护作用

目的:探讨重组人促红细胞生成素(rHuEPO)预处理对体外循环下行二尖瓣置换术患者的心肌保护作用及其可能的机制.方法:选择择期在体外循环下行二尖瓣置换术的风湿性心脏病患者30例,随机分为实验组和对照组.实验组患者从术前3 d 起,皮下注射rHuEPO 200 IU/kg,1次/d.2组其他处理条件相同.于术前及术后3 d测定血常规.于术前,主动脉开放后2 h、6 h、12 h及24 h测定血清心肌酶谱及肌钙蛋白I(cTnI)的水平.结果:术前、术后血常规无显著变化.实验组在主动脉开放后各时间点血清心肌酶谱及肌钙蛋白水平显著低于对照组,差异具有统计学意义( P＜0.05).结论:rHuEPO预处理 (皮下注射)能减轻二尖瓣置换术患者的血清心肌酶及肌钙蛋白表达,具有显著的保护心肌作用.     

Cardiac surgery in octogenarians; peri-operative outcome and long-term results.

AIMS: Because the elderly are increasingly referred for operation, we reviewed the results of cardiac surgery in patients of 80 years or older. METHODS AND RESULTS: Records of 182 consecutive octogenarians who had had cardiac operations between 1992 and 1998 were reviewed. Follow-up was 100% complete. Seventy patients had coronary grafting (CABG), 70 aortic valve replacement, 30 aortic valve replacement+CABG, and 12 mitral valve repair/replacement. Rates of hospital death, stroke, and prolonged stay (>14 days) were as follows: CABG: 7 (10%), 2 (2.8%) and 41 (58%); aortic valve replacement: 6 (8.5%), 2 (2.8%) and 32 (45.7%); aortic valve replacement+CABG: 8 (26.5%), 1 (3.8%) and 14 (46.6%); mitral valve repair/replacement: 3 (25%), 1 (8.3%) and 5 (41.6%). Multivariate predictors (P<0.05) of hospital death were New York Heart Association functional class, urgent procedure, prolonged cardiopulmonary bypass time, and, after aortic valve replacement, previous percutaneous aortic valvuloplasty. Ascending aortic atheromatous disease was predictive of stroke, while pre-operative myocardial infarction was predictive of prolonged hospital stay. Actuarial 5-year survival was as follows: CABG, 65.8+/-8.8%; aortic valve replacement, 63.6+/-7.1%; aortic valve replacement+CABG, 62.4+/-6.8%; mitral valve repair/replacement, 57.1+/-5.6%; and total, 63.0+/-5.6%. Multivariate predictors of late death were pre-operative myocardial infarction, and urgent procedure. Ninety percent of long-term survivors were in New York Heart Association class I or II, and 87% believed having a heart operation after age 80 years was a good choice. CONCLUSION: Cardiac operations are successful in most octogenarians with increased hospital mortality, and longer hospital stay. Long-term survival and quality of life are good.     

Cardiac surgery in patients over the age of 80 years

The risk-benefit relationship of open heart surgery in octogenarians is not well established. Eighty consecutive patients over the age of 80 who underwent cardiac operations under cardiopulmonary bypass were evaluated. Twenty-five patients were in functional class IV, 42 in class III, and 13 in class II. Forty-four patients had only coronary artery bypass grafts (CABG), 12 only aortic valve replacement (AVR), 6 only mitral valve replacement (MVR), 12 CABG and AVR, 4 CABG and MVR, 1 CABG and aneurysmectomy, and 1 had resection of left atrial myxoma. Operative mortality (within 30 days) was 12.5% for the group. Mortality was related to bleeding, left ventricular failure, primary ventricular fibrillation, pulmonary failure, and renal failure. Mortality was higher in patients with (1) advanced functional class, (2) mitral valve replacement, (3) postoperative hemorrhage, and (4) associated pulmonary disease. While a generally conservative approach is recommended for octogenarian patients, many with life-threatening cardiac disease, especially those free of major multisystem illnesses, should not be denied the benefit of surgical treatment.     

Cardiac surgery in patients on chronic hemodialysis: short and long-term survival

OBJECTIVE: Open-heart surgery carries a high risk for hemodialysis patients. This study focuses on the short and long-term outcomes of hemodialysis patients undergoing heart surgery. DESIGN: The study was carried out as a retrospective analysis in the Department of Cardiothoracic Surgery in a large university-affiliated hospital. PATIENTS: 115 hemodialysis patients underwent cardiac surgery in our department between 1 July 1996 and 31 July 2006. 67.5 % (77 patients) underwent isolated coronary artery bypass grafting (CABG), 13.2 % (15 patients) underwent isolated aortic valve replacement (AVR) and 20.2 % (23 patients) underwent mitral valve surgery or combined valve and coronary artery bypass grafting or multiple valve surgery. METHODS: The relationship between several variables (age, sex, hypertension, diabetes, and previous myocardial infarction, type of disease, preoperative ejection fraction, and congestive heart failure) and operative (30 days) mortality and late survival was analyzed. RESULTS: The overall 30-day mortality was 18.3 % (21 patients). It was 13 % (10/77 patients) for the isolated CABG group and 13.3 % (2/15) for the isolated AVR group. Patients undergoing combined valve and coronary surgery or multiple valve surgery had a higher perioperative mortality of 39.1 % (9/23) compared to the isolated CABG and isolated AVR patients. Perioperative death was also higher in patients with moderate and severe LV dysfunction, and in patients with diabetes. The duration of dialysis periods was not related to perioperative death. Mean follow-up was 26.4 +/- 29.7 months (0.1 to 104 months). Actuarial survival at 1 year and 5 years was 76 % and 55 % for isolated CABG, 59 % and 21 % for isolated AVR, and 44 % and 33 % for all other cases, respectively (log rank P = 0.001). CONCLUSION: Patients on dialysis have a high risk of perioperative mortality and poor long-term survival rates. Mortality is higher and survival is worse after combined CABG and valve-related procedures or multiple valve surgery than after isolated CABG and AVR.     

The effect of glutamate and aspartate on myocardial protection at cardiopulmonary bypass]

OBJECTIVE: To determine whether glutamat and aspartat enriched cold crystalloid cardioplegia which was given in antegrade way has any effect on the myocardial protection during cardiopulmonary bypass. METHODS: Thirty-four patients who were electively undergone open heart surgery at Osmangazi University Faculty of Medicine, thoracic and cardiovascular surgery department, between March 2001 and May 2001 were included in this study. The patients were divided in two groups, each consisting of 17 patients. In group 1 coronary artery bypass surgery (CABG) was performed in 11 patients, mitral valve replacement (MVR) in 3 patients, aortic valve replacement (AVR) in 1 patient and AVR and MVR in 2 patients. While in group 2 CABG was performed in 13 patients and MVR was done in 4 patients. Group 1 patients received antegrade glutamat and aspartat (15 mmol/L) enriched cold crystalloid cardioplegia and group 2 patients were given cold crystalloid cardioplegia by antegrade route. Age, gender, diabetes mellitus, hypertension, preoperative myocardial infarction, smoking, ejection fraction, aortic cross-clamp time, need to defibrillation, inotropic support, and intraaortic balloon pump were recorded. The levels of cardiac troponin I (cTI) and creatine kinase myocardial band fraction (CK-MB) were measured in arterial blood samples at five different times. Statistical analysis was performed using Student's t-test and Chi-square test. RESULTS: There were no statistically significant differences in cTI and CK-MB values in blood samples taken at 5 different times pre and postoperatively between group 1 and group 2. CONCLUSION: It is concluded that glutamat and aspartat enriched cold crystalloid cardioplegia does not have any effect on myocardial protection.     

Prediction of operative mortality after valve replacement surgery.

OBJECTIVES: We sought to develop national benchmarks for valve replacement surgery by developing statistical risk models of operative mortality. BACKGROUND: National risk models for coronary artery bypass graft surgery (CABG) have gained widespread acceptance, but there are no similar models for valve replacement surgery. METHODS: The Society of Thoracic Surgeons National Cardiac Surgery Database was used to identify risk factors associated with valve surgery from 1994 through 1997. The population was drawn from 49,073 patients undergoing isolated aortic valve replacement (AVR) or mitral valve replacement (MVR) and from 43,463 patients undergoing CABG combined with AVR or MVR. Two multivariable risk models were developed: one for isolated AVR or MVR and one for CABG plus AVR or CABG plus MVR. RESULTS: Operative mortality rates for AVR, MVR, combined CABG/AVR and combined CABG/ MVR were 4.00%, 6.04%, 6.80% and 13.29%, respectively. The strongest independent risk factors were emergency/salvage procedures, recent infarction, reoperations and renal failure. The c-indexes were 0.77 and 0.74 for the isolated valve replacement and combined CABG/valve replacement models, respectively. These models retained their predictive accuracy when applied to a prospective patient population undergoing operation from 1998 to 1999. The Hosmer-Lemeshow goodness-of-fit statistic was 10.6 (p = 0.225) for the isolated valve replacement model and 12.2 (p = 0.141) for the CABG/valve replacement model. CONCLUSIONS: Statistical models have been developed to accurately predict operative mortality after valve replacement surgery. These models can be used to enhance quality by providing a national benchmark for valve replacement surgery.     

七氟醚复合麻醉对纯二尖瓣病变患者术后认知功能及神经功能的影响

目的探讨七氟醚复合麻醉对纯二尖瓣病变患者术后认知功能及神经功能的影响。 方法选择2016年3月至2017年10月胶州市人民医院择期行心脏二尖瓣置换术的纯二尖瓣病变患者112例,以随机数表法分为对照组(56例)和试验组(56例)。对照组接受丙泊酚复合麻醉,试验组接受七氟醚复合麻醉。对比两组麻醉诱导前、体外循环开始后0.5 h、术毕、术后12 h的血清神经损伤指标[神经元特异性烯醇化酶(NSE)、S－100β蛋白]水平,术前、术后2 d的认知功能评分(MMSE),术后2 d时认知功能障碍(POCD)发生率。 结果试验组体外循环开始后0.5 h、术毕、术后12 h的血清NSE、S－100β蛋白水平均较对照组低(P<0.05)。试验组术后2 d的MMSE评分高于对照组,POCD发生率低于对照组(P<0.05)。 结论七氟醚复合麻醉对纯二尖瓣病变患者术后认知功能及神经功能影响小,利于减少术后认知功能障碍的发生。     

Outcomes of cardiac surgery in patients > or = 80 years: results from the National Cardiovascular Network

OBJECTIVES: The purpose of this study was to evaluate characteristics and outcomes of patients age > or =80 undergoing cardiac surgery. BACKGROUND: Prior single-institution series have found high mortality rates in octogenarians after cardiac surgery. However, the major preoperative risk factors in this age group have not been identified. In addition, the additive risks in the elderly of valve replacement surgery at the time of bypass are unknown. METHODS: We report in-hospital morbidity and mortality in 67,764 patients (4,743 octogenarians) undergoing cardiac surgery at 22 centers in the National Cardiovascular Network. We examine the predictors of in-hospital mortality in octogenarians compared with those predictors in younger patients. RESULTS: Octogenarians undergoing cardiac surgery had fewer comorbid illnesses but higher disease severity and surgical urgency than younger patients. Octogenarians had significantly higher in-hospital mortality after cardiac surgery than younger patients: coronary artery bypass grafting (CABG) only (8.1% vs. 3.0%), CABG/aortic valve (10.1% vs. 7.9%), CABG/mitral valve (19.6% vs. 12.2%). In addition, they had twice the incidence of postoperative stroke and renal failure. The preoperative clinical factors predicting CABG mortality in the very elderly were quite similar to those for younger patients with age, emergency surgery and prior CABG being the powerful predictors of outcome in both age categories. Of note, elderly patients without significant comorbidity had in-hospital mortality rates of 4.2% after CABG, 7% after CABG with aortic valve replacement (CABG/AVR), and 18.2% after CABG with mitral valve replacement (CABG/MVR). CONCLUSIONS: Risks for octogenarians undergoing cardiac surgery are less than previously reported, especially for CABG only or CABG/AVR. In selected octogenarians without significant comorbidity, mortality approaches that seen in younger patients.     

Apico-Aortic Conduit for severe aortic stenosis: Technique,applications, and systematic review

Patients referred for aortic valve replacement are often elderly and may have increased surgical risk associated with ascending aortic calcification, left ventricular dysfunction, presence of coronary artery disease, previous surgery, and/or presence of several co-morbidities. Some of these patients may not be considered candidates for conventional surgery because of their high risk profile. While transcatheter aortic valve replacement constitutes a widely accepted alternative, some patients may not be eligible for this modality due to anatomic factors. Apico-Aortic Conduit (AAC) insertion (aortic valve bypass surgery) constitutes a possible option in those patients. Apico-Aortic Conduit is not a new technique, as it has been used for decades in both pediatric and adult populations. However, there is a resurging interest in this technique due to the expanding scope of elderly patients being considered for the treatment of aortic stenosis. Herein, we describe our surgical technique and provide a systematic review of recent publications on AAC insertion, reporting that there is continued use and several modifications of this technique, such as performing it through a small thoracotomy without the use of the cardiopulmonary bypass.Abbreviations: AAC, Apico Aortic Conduit; AS, aortic stenosis; AVR, aortic valve replacement; BSA, body surface area; CABG, coronary artery bypass grafting surgery; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CPB, cardiopulmonary bypass; DHCA, deep hypothermic circulatory arrest; FEM-FEM, femoro-femoral; ITA, internal thoracic artery; LITA, left internal thoracic artery; LVH, left ventricular hypertrophy; LVOT, left ventricle outflow tract; NYHA, New York Heart Association; MDCT, multidetector-computerized tomography; MVR, mitral valve replacement; OPCAB, off pump coronary artery bypass; PH, pulmonary hypertension; RITA, right internal thoracic artery; TEE, transesophageal echocardiography; TAVI, transcatheter aortic valve implantation     

107例双瓣置换手术临床分析

目的：回顾分析107例双瓣置换手术围手术期资料,探讨双瓣置换的围手术期临床特点。方法：手术在体外循环,中度低温情况下进行,其中保留二尖瓣及瓣下结构98例,左房折叠10例,二尖瓣成形82例,同时行冠脉旁路移植术（CABG）5例。结果：105例患者康复出院,死亡2例,死因分别是低心排综合症及恶性心律失常。结论：双瓣膜置换是治疗瓣膜病变的有效手段,适当的手术时机,不断改进和提高体外循环技术,手术技巧,尽量保留瓣下结构,可降低手术风险,提高疗效。