三维经食管超声心动图定量评价左心室流出道形态与搏出量的临床研究

Clinical study of three-dimensional transesophageal echocardiography for quantitatively assessing left ventricular outflow tract geometry and stroke volume

目的应用三维经食管超声心动图(3D TEE)研究左室流出道(LVOT)形态,探讨连续方程法低估主动脉瓣口面积的理论依据。方法回顾性分析2010年5月至2011年2月美国维克森林大学医学中心50例患者的二维经胸超声心动图(2D TTE)及3DTEE资料,在远段(主动脉瓣环,A1)、中段(主动脉瓣环以下5 mm,A2)、近段(主动脉瓣环以下10 mm,A3)三个平面测量LVOT直径并计算LVOT横截面积(CSA)。比较2D TTE圆形面积公式(2D TTE_(circular))、3D TEE椭圆形面积公式(3D TEE_(elliptical))与3D TEE几何学方法(3D TEE_(planimetry))计算的CSA与搏出量(SV)。结果 3D TEE显示多数患者LVOT呈漏斗形(76%),CSA在A1平面最小,呈圆形,在A2及A3平面增大,呈椭圆形。在A1平面,CSA_(circular)、CSA_(elliptical)、CSA_(planimetry)分别为(3.7±0.9)cm^2、(3.9±0.8)cm^2、(3.9±1.0)cm^2,差异无统计学意义(F=1.025,P=0.45);在A2及A3平面,CSA_(circular)分别为(3.4±0.8)cm^2、(3.5±0.9)cm^2,显著小于CSAplanimetry的(4.0±1.0)cm^2、(5.0±1.4)cm^2,差异有统计学意义(F=8.055、22.098,P=0.001、<0.001)。A1平面,SV_(circular)及SV_(elliptical)、SV_(planimetry)差异无统计学意义(F=0.579,P=0.56);A2及A3平面,SV_(circular)分别为(64±18)ml、(67±19)ml,显著小于SV_(planimetry)的(76±23)ml、(95±33)ml(F=5.168、15.638,P=0.004、<0.001)。结论 LVOT呈不规则漏斗形,其最小横截面积位于瓣环水平;应用三维超声心动图测量LVOT直径或CSA能够更准确地计算左室每搏量,避免低估主动脉瓣口面积,提高判断主动脉瓣狭窄程度的准确性。

Objective To assess left ventricular outflow tract(LVOT)geometry using threedimensional transesophageal echocardiography(3D TEE),in order to provide a theoretical basis for underestimation of aortic valve area by continuity equation.Methods Fifty patients who underwent twodimensional transthoracic echocardiography(2D TTE)and 3D TEE of 50 patients from May 2010 to February 2011 were assessed retrospectively.LVOT diameters were measured at distal(aortic annulus,A1),middle(5 mm from the annulus)and proximal(10 mm from the annulus)level,and cross-sectional areas(CSA)were calculated respectively.CSA and stroke volume(SV)calculated from 2D TTE circular area formula(2D TTEcircular),3D TEE elliptical area formula(3D TEEelliptical)and 3D TEE planimetry(3D TEEplanimetry)were compared.Results 3D TEE revealed that LVOT was funnel-shaped in most of the patients(76%).CSA was circular at A1 with the smallest area,and was elliptic at A2 and A3 with larger areas.There was no significant difference among CSAcircular[(3.7±0.9)cm2],CSAelliptical[(3.9±0.8)cm2]and CSAplanimetry[(3.9±1.0)cm2]at A1 level(F=1.025,P=0.45).CSAcircular was(3.4±0.8)cm2 at A2 and(3.5±0.9)cm2 at A3,and CSAplanimetry was(4.0±1.0)cm2 at A2 and(5.0±1.4)cm2 at A3.CSAcircular was significantly smaller than CSAplanimetry at both A2 and A3 leves(F=8.055,22.098;P=0.001,<0.001).There was no significant difference among SVcircular,SVelliptical,and SVplanimetry at A1 level(F=0.579,P=0.56).SVcircular was(64±18)ml at A2 and(67±19)ml at A3,and SVplanimetry was(76±23)ml at A2 and(95±33)ml at A3.SVcircular was significantly smaller than SVplanimetry at both A2 and A3 level(F=5.168,15.638;P=0.004,<0.001).Conclusions LVOT is uniformly funnel-shaped with the smallest CSA at the annulus.Using of 3D measurement of LVOT diameters or area may improve the accuracy of calculating SV,reduce the risk for underestimation of aortic valve area and improve accuracy of diagnosing aortic stenosis.