运动负荷超声评价主动脉瓣置换术后左心室收缩功能储备

目的:应用二维超声斑点追踪技术,评价主动脉瓣置换术后运动负荷试验中的左心室收缩功能储备。方法:21例因重度主动脉瓣狭窄进行瓣膜置换术的患者(左心室射血分数>50%)行运动负荷超声心动图检查,应用二维超声斑点追踪技术测量运动负荷试验中静息状态下及峰值负荷时的左心室收缩期长轴整体应变率(GLSRs),同时记录峰值负荷时的心肌摄氧量(pVO2)。结果与21例正常健康对照者进行比较。结果:静息状态下,病例组与对照组超声指标无明显差异。峰值负荷时,病例组pVO2低于正常组(P<0.05);GLSRs及二尖瓣环心肌收缩速度(Sm)均明显低于正常组(P<0.001)且与pVO2呈正相关(GLSRs:r=0.60,P=0.0007;Sm:r=0.65,P=0.002)。多重线性回归分析,病例组峰值负荷时的左心室收缩期应变率为pVO2的唯一影响因素。结论:主动脉瓣狭窄患者瓣膜置换术后,尽管静息状态下左心室功能正常,但运动负荷试验后,左心室收缩功能储备仍然低于正常。

Evaluation of left ventricular contractile reserve after aortic valve replacement by exercise echocardiography

Objective:To evaluate the left ventricular(LV) contractile reserve after aortic valve replacement(AVR) in aortic stenosis(AS) by two-dimensional speckle tracking echocardiography(STE) during exercise.Methods:21 AVR patients(age(61±12) years,14 male) with normal LV ejection fraction(LVEF>50%) and 21 age and sex matched normal controls(age(57±9) years,10 male) were studied.Global longitudinal systolic strain rate(GLSRs) using STE and Doppler echocardiographic parameters were measured at rest and peak exercise.Peak oxygen consumption(pVO2) was also collected at peak exercise.Results:At rest,the two groups had comparable resting echocardiographic measurements.At peak exercise,pVO2 was lower in patients than controls(P<0.05).GLSRs(P<0.001) and mitral annular systolic myocardial velocity(Sm)(P<0.001) were also significantly lower in patients than controls.In patients,pVO2 correlated with peak exercise GLSRs(r=0.60,P=0.0007) and Sm(r=0.65,P=0.002).In a multivariate model,peak exercise GLSRs was the only independent predictor of pVO2 in the patients group.Conclusion:Exercise capacity is subnormal after AVR for aortic stenosis,irrespective of normal LVEF suggesting compromised myocardial functional reserve after surgery.