婴幼儿圆锥动脉干畸形型先天性心脏病合并冠状动脉异位起源的MSCT诊断

目的:研究圆锥动脉干畸形型先天性心脏病合并冠状动脉异位起源的类型、发生率、构成比,探讨术前MSCT心脏成像诊断对术前计划制定的重要性。方法:回顾性分析276例经手术证实的圆锥动脉干畸形型先天性心脏病,所有患儿均在本院行MSCT心脏成像,并记录先天性心脏病类型、冠状动脉异位起源的类型及数量。对不同类型先天性心脏病的冠状动脉异位起源的发生率采用行×列Person卡方检验进行比较,对不同先天性心脏病的冠状动脉异位起源构成比采用Fisher确切概率法进行比较。与手术结果对照,探讨术前MSCT心脏成像诊断对术前计划制定的重要性。结果:圆锥动脉干畸形型先天性心脏病共276例,合并冠状动脉异位起源者47例,平均发病率为17%,其中肺动脉闭锁PA 11例,大动脉转位TGA 15例,法洛氏四联症TOF 4例,永存动脉干PTA 6例,右室双出口DORV 11例。在本组圆锥动脉干畸形型先天性心脏病伴发冠状动脉异位起源中,单冠状动脉SCA最多,占48.94%,其次为对侧冠状动脉或无冠窦起源OO,占29.79%,冠状动脉多发起源MO占14.89%,冠状动脉高位起源HO为4.26%,冠状动脉肺动脉起源PO最少,占2.13%。Fisher确切概率法比较,卡方值为15.452,P值为0.472,说明不同类型先天性心脏病的冠状动脉异位起源构成比差异无统计学意义,可以认为不同类型先天性心脏病的冠状动脉异位起源构成比不全相同,与圆锥动脉干畸形的严重程度相关。本研究冠状动脉异位起源发生率由高到低依次为PTA(35.3%)>TGA(27.3%)>DORV(25%)>PA(16.9%)>TOF(4.2%)。但是TGA的构成比高达32%。结论:不同类型圆锥动脉干畸形型先天性心脏病合并冠状动脉异位起源的发生率及构成比不同,与圆锥动脉干畸形的严重程度相关;我们应该更多地关注大动脉转位伴发冠状动脉异位起源的患儿。

On Belly-flap for Pitch Control at Transonic Airfoil

One of the issues about Blended-Wing-Body configuration （BWB） is its difficulty in pitch control due to the missing tail. To solve this problem, a novel pitch control surface, belly-flap, has been presented. In this paper, the feasibility of belly-flap being used as a transonic pitch control device for tailless configuration is investigated on a BWB in-body airfoil, using the computationalfluid dynamic （CFD） method. The size, location and deflection angle of the flap are studied to detect their effect on the aerodynamic characteristics. The results reveal that the bubble separation due to the belly-flap can affect shock position on the upper surface of the airfoil and change the surface pressure distribution. By choosing appropriate geometry parameters, the load distribution can be improved to obtain significant pitch-up moment increment in a wide angle of attack with no lift-loss and less lift-drag ratio decrement.