Sundareswaran Kartik S, Kanter Kirk R, Kitajima Hiroumi D, Krishnankutty Resmi, Sabatier Jennifer F, Parks W James, Sharma Shiva, Yoganathan Ajit P, Fogel Mark
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0535, USA.
Ann Thorac Surg. 2006 Oct;82(4):1267-75; discussion 1275-7. doi: 10.1016/j.athoracsur.2006.05.020.
Unfavorable cardiac mechanics in children with hypoplastic left heart syndrome (HLHS) when compared with other single-ventricle defects may affect long-term morbidity and outcome. Using noninvasive phase contrast magnetic resonance imaging (PC MRI), we examined cardiac mechanics in children with HLHS and compared the results to other single-ventricle defects.
Eighteen children with HLHS and 18 children with other single-ventricle defects were studied after the Fontan operation. Phase contrast MRI scans were obtained perpendicular to the ascending aorta, and flow was quantified using an in-house segmentation and reconstruction scheme. The total power output was determined using the modified Bernoulli equation along with cardiac output and systemic vascular resistance index.
Compared with non-HLHS congenital heart defects, children with HLHS had significantly lower power output (1.40 +/- 0.39 versus 1.78 +/- 0.38 W/m2, p < 0.004) and cardiac index (3.15 +/- 0.97 versus 4.09 +/- 1.23 L x Min(-1) x m(-2), p < 0.009) with a concomitant higher systemic vascular resistance index (28.94 +/- 11.5 versus 22.7 +/- 8.53 WU, p < 0.03) despite generating similar systolic blood pressures (112.9 +/- 22.4 versus 115.2 +/- 23 mm Hg, p > 0.05).
Minimally invasive measurements with PC MRI in children with HLHS showed significantly lower power output and cardiac index when compared with other single-ventricle physiologies. Abnormal aortic flow patterns may contribute to power loss and may have long-term survival and morbidity implications associated with the Fontan procedure. Elevated systemic vascular resistance index despite similar blood pressure opens avenues for therapeutic intervention for afterload reduction.
与其他单心室缺陷相比，左心发育不全综合征（HLHS）患儿的心脏力学不良可能会影响长期发病率和预后。我们使用无创相位对比磁共振成像（PC MRI）检查了HLHS患儿的心脏力学，并将结果与其他单心室缺陷进行了比较。
对18例HLHS患儿和18例其他单心室缺陷患儿在Fontan手术后进行了研究。垂直于升主动脉进行相位对比MRI扫描，并使用内部分割和重建方案对血流进行量化。使用修正的伯努利方程以及心输出量和全身血管阻力指数来确定总功率输出。
与非HLHS先天性心脏病相比，HLHS患儿的功率输出（1.40±0.39对1.78±0.38 W/m²，p<0.004）和心脏指数（3.15±0.97对4.09±1.23 L×Min⁻¹×m⁻²，p<0.009）显著降低，同时全身血管阻力指数更高（28.94±11.5对22.7±8.53 WU，p<0.03），尽管收缩压相似（112.9±22.4对115.2±23 mmHg，p>0.05）。
与其他单心室生理情况相比，对HLHS患儿进行PC MRI的微创测量显示功率输出和心脏指数显著降低。异常的主动脉血流模式可能导致功率损失，并可能对Fontan手术的长期生存和发病率产生影响。尽管血压相似，但全身血管阻力指数升高为降低后负荷的治疗干预开辟了途径。
