Salaymeh K J, Banerjee A
Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Am Heart J. 2001 Sep;142(3):549-55. doi: 10.1067/mhj.2001.116763.
Pathologic studies and surgical observations of thickened aortic walls have suggested an increase in aortic stiffness in patients with Williams syndrome. However, in vivo objective evaluation of aortic and arterial stiffness in Williams syndrome are lacking. Moreover, systemic hypertension, although prevalent in Williams syndrome, does not have a well-defined mechanism in this syndrome. Therefore, the purpose of this study was to quantitate aortic stiffness and arterial compliance in an objective manner, as well as to determine their roles in development of hypertension, in children with Williams syndrome.
We studied 13 patients with Williams syndrome (aged 3-12 years) and 16 age-matched control subjects. Aortic stiffness was calculated from the beta index as follows: beta = (ln[P(s)/P(d)])/ ([D(s) - D(d)]/D(d)), where P(s) and P(d) are systolic and diastolic blood pressures and D(s) and D(d) are systolic and diastolic aortic dimensions, respectively. Arterial compliance (C) was calculated by the area method: C= (A(d) x CO x CL) / (A(t) x [P(es) - P(d)]), where A(t) is the total area and A(d) is the area under the diastolic portion of the arterial pulse tracing, CO is the cardiac output, CL is the cycle length, and P(es) is aortic end-systolic pressure.
In patients with Williams syndrome, the beta index was 2-fold higher than in control patients (9.02 +/- 3.15 vs 4.43 +/- 0.96, P <.005). Moreover, there was a strong positive correlation between the beta index and the systolic blood pressure (r = 0.8 and P <.0001). Compliance was decreased by 42% (0.41 +/- 0.11 vs 0.71 +/- 0.10 mL/mm Hg, P <.05), suggesting decreased arterial compliance.
Our study indicates that in vivo arterial stiffness is increased in patients with Williams syndrome. We speculate that increased arterial stiffness may be the predisposing cause of systemic hypertension in Williams syndrome.
对增厚主动脉壁的病理学研究和手术观察表明，威廉姆斯综合征患者的主动脉僵硬度增加。然而，缺乏对威廉姆斯综合征患者主动脉和动脉僵硬度的体内客观评估。此外，系统性高血压虽然在威廉姆斯综合征中普遍存在，但在该综合征中其发病机制尚不明确。因此，本研究的目的是以客观方式量化威廉姆斯综合征患儿的主动脉僵硬度和动脉顺应性，并确定它们在高血压发展中的作用。
我们研究了13例威廉姆斯综合征患者（年龄3 - 12岁）和16例年龄匹配的对照受试者。主动脉僵硬度通过β指数计算如下：β = (ln[P(s)/P(d)]) / ([D(s) - D(d)]/D(d))，其中P(s)和P(d)分别为收缩压和舒张压，D(s)和D(d)分别为收缩期和舒张期主动脉内径。动脉顺应性（C）通过面积法计算：C = (A(d) × CO × CL) / (A(t) × [P(es) - P(d)])，其中A(t)为总面积，A(d)为动脉脉搏描记舒张期部分下的面积，CO为心输出量，CL为心动周期长度，P(es)为主动脉收缩末期压力。
威廉姆斯综合征患者的β指数比对照患者高2倍（9.02 ± 3.15 vs 4.43 ± 0.96，P <.005）。此外，β指数与收缩压之间存在强正相关（r = 0.8，P <.0001）。顺应性降低了42%（0.41 ± 0.11 vs 0.71 ± 0.10 mL/mm Hg，P <.05），提示动脉顺应性降低。
我们的研究表明，威廉姆斯综合征患者的体内动脉僵硬度增加。我们推测动脉僵硬度增加可能是威廉姆斯综合征中系统性高血压的易感原因。
