Stefano P L, Oppizzi M, Alfieri O
Divisione di Cardiochirurgia, IRCCS Ospedale San Raffaele Via Olgettina, 60 20132 Milano.
Ital Heart J Suppl. 2001 Nov;2(11):1224-30.
Prophylactic valve replacement in asymptomatic patients with severe aortic stenosis is controversial. Most authors consider that patients could be managed without surgery until symptoms develop. The incidence of sudden death in patients without symptoms is low, < 1%/year and valve replacement is complicated by an operative mortality up to 5 and 1-2% of incidence of valve-related major events. Early surgical approach is suggested by several observations. The first one is the unpredictable risk of myocardial fibrosis after long standing left ventricular hypertrophy and pressure overload, with associated systolic and diastolic dysfunction. Left ventricular impairment can persist after valve replacement influencing exercise capacity and survival in selected patients. On the other hand, major improvement in myocardial protection techniques, intraoperative monitoring with transesophageal echocardiography, prosthetic design (stentless, supra-annular), all have reduced in-hospital mortality and morbidity. More precise recommendations can be made according to an improved characterization of the patients from fast to slow evolution, according to age, type of aortic stenosis, degree of calcification, changes in transaortic gradients over time, tolerance to exercise test and response of aortic valve area to dobutamine. In patients with high risk of progression (severely calcified valve, Doppler velocity > 4 m/s, rapidly increasing with time), indirect evidence of myocardial fibrosis (excessive left ventricular hypertrophy, systolic or diastolic dysfunction), and need of myocardial revascularization, an early surgical approach should be considered.
对无症状的重度主动脉瓣狭窄患者进行预防性瓣膜置换存在争议。大多数作者认为,在症状出现之前,患者可以不进行手术治疗。无症状患者的猝死发生率较低,<1%/年,而瓣膜置换手术的并发症包括手术死亡率高达5%以及瓣膜相关重大事件发生率为1 - 2%。多项观察结果提示应采取早期手术治疗。第一个是长期左心室肥厚和压力超负荷后心肌纤维化的风险不可预测,伴有收缩和舒张功能障碍。瓣膜置换后左心室功能损害可能持续存在,影响部分患者的运动能力和生存率。另一方面,心肌保护技术、经食管超声心动图术中监测、假体设计(无支架、瓣环上)等方面的重大改进,均降低了住院死亡率和发病率。根据患者从快速到缓慢进展的更精确特征描述,可依据年龄、主动脉瓣狭窄类型、钙化程度、经主动脉梯度随时间的变化、运动试验耐受性以及主动脉瓣面积对多巴酚丁胺的反应等做出更精确的建议。对于进展风险高(瓣膜严重钙化、多普勒速度>4 m/s、随时间快速增加)、心肌纤维化的间接证据(左心室过度肥厚、收缩或舒张功能障碍)以及需要心肌血运重建的患者,应考虑早期手术治疗。