Kim Hyung Wook, Park Cheol Whee, Shin Young Shin, Kim Young Soo, Shin Seok Jun, Kim Yong-Soo, Choi Euy Jin, Chang Yoon Sik, Bang Byung Kee
Division of Nephrology, Department of Internal Medicine, College of Medicine, Catholic University of Korea, Seoul, Korea.
Nephron Clin Pract. 2006;102(1):c21-9. doi: 10.1159/000088295. Epub 2005 Sep 13.
Sudden cardiac death is common in patients on hemodialysis (HD), and its rate is as high as 25% of all cardiac deaths associated with left ventricular hypertrophy (LVH) and secondary hyperparathyroidism. A prolonged QT interval on standard electrocardiography is related to an increase in sudden death in various patient groups. It is also well known that LVH has been noted in uremic patients with high parathyroid hormone levels.
To evaluate the response of intravenous calcitriol treatment on the QT interval and LVH in HD patients with secondary hyperparathyroidism (intact parathyroid hormone, iPTH, > 450 ng/ml), echocardiographic, electrocardiographic (ECG), and biochemical assessments were performed over a 15-week period in 25 HD patients before and after intravenous calcitriol treatment. We also evaluated 25 age-, sex-, HD duration-, and BMI-matched HD control patients with secondary hyperparathyroidism.
In patients receiving intravenous calcitriol, a significant reduction in iPTH levels (p < 0.05) and alkaline phosphatase levels (p < 0.01) was found without changes in values of serum calcium and ionized Ca2+, phosphorus, Na+, K+, Mg2+, hematocrit, blood pressure, or other hemodynamic changes. Echocardiograms showed significant decreases in the thickness of the interventricular septum (p < 0.05), left posterior wall thickness (p < 0.05), and left ventricle mass index (LVMi, p < 0.01). In addition, sequential ECG measurement in patients with calcitriol treatment showed significant reductions in QTcmax (QTmax interval corrected for heart rates, p < 0.01) and QTc dispersion (QT dispersion corrected for heart rates, p < 0.01). However, in the control patients, biochemical, hemodynamic, and ECG changes, as well as myocardial structural and functional changes were not seen. Multiple regression analysis in all patients indicated that iPTH and LVMi levels were independent predictors of QTcmax while the LVMi level was the only independent predictor of QTc dispersion (p < 0.05).
Our study showed a significant correlation between LVMi and QT dispersion in HD patients with secondary hyperparathyroidism. Intravenous calcitriol treatment, to be used for the control of secondary hyperparathyroidism, was found to cause regression of myocardial hypertrophy and a reduction in the QTc interval and dispersion, without biochemical and hemodynamic changes. These findings suggest that an active vitamin D metabolite has a cardioprotective action in HD patients.
心脏性猝死在血液透析（HD）患者中很常见，其发生率高达所有与左心室肥厚（LVH）和继发性甲状旁腺功能亢进相关的心脏性死亡的25%。标准心电图上QT间期延长与各类患者群体猝死风险增加有关。众所周知，甲状旁腺激素水平高的尿毒症患者存在LVH。
为评估静脉注射骨化三醇治疗对继发性甲状旁腺功能亢进（完整甲状旁腺激素，iPTH，>450 ng/ml）的HD患者QT间期和LVH的影响，在25例HD患者静脉注射骨化三醇治疗前后的15周内进行了超声心动图、心电图（ECG）和生化评估。我们还评估了25例年龄、性别、HD病程和BMI匹配的继发性甲状旁腺功能亢进的HD对照患者。
接受静脉注射骨化三醇的患者，iPTH水平（p<0.05）和碱性磷酸酶水平显著降低（p<0.01），而血清钙、离子钙、磷、钠、钾、镁水平、血细胞比容、血压或其他血流动力学参数无变化。超声心动图显示室间隔厚度（p<0.05）、左后壁厚度（p<0.05）和左心室质量指数（LVMi，p<0.01）显著降低。此外，骨化三醇治疗患者的连续心电图测量显示QTcmax（校正心率后的QTmax间期，p<0.01）和QTc离散度（校正心率后的QT离散度，p<0.01）显著降低。然而，对照患者未观察到生化、血流动力学和心电图变化，以及心肌结构和功能变化。所有患者的多元回归分析表明，iPTH和LVMi水平是QTcmax的独立预测因子，而LVMi水平是QTc离散度的唯一独立预测因子（p<0.05）。
我们的研究表明，继发性甲状旁腺功能亢进的HD患者中LVMi与QT离散度之间存在显著相关性。发现用于控制继发性甲状旁腺功能亢进的静脉注射骨化三醇治疗可使心肌肥厚消退，并使QTc间期和离散度降低，且无生化和血流动力学变化。这些发现表明活性维生素D代谢物对HD患者具有心脏保护作用。
