血管舒张反应预测盐酸米多君治疗儿童血管迷走性晕厥疗效价值研究

The predictive value of flow-mediated vasodilation on therapeutic efficacy of midorine hydrochloride for vasovagal syncope in children

目的通过测定肱动脉血流介导的血管舒张反应(flow-mediated vasodilation,FMD)研究盐酸米多君治疗血管迷走性晕厥(vasovagal syncope,VVS)儿童的疗效预测指标。方法 2009年2月至2009年8月在北京大学第一医院就诊的不明原因晕厥儿童共24例,经直立倾斜试验诊断为VVS,确诊后检测FMD并给予盐酸米多君治疗,1个月后门诊复诊并复查FMD。治疗满3个月后进行电话随访,随访时间10～18个月,平均(14.5±2.3)个月,随访结束时无复发者判为有效,反之无效。采用ROC曲线分析FMD对盐酸米多君治疗VVS患儿的疗效预测价值。结果 VVS患儿经盐酸米多君治疗后FMD较治疗前明显降低[(11.07±3.11)%VS(7.64±1.81)%,P<0.001],而治疗前后的平卧心率及收缩压、基础肱动脉内径差异均无统计学意义。随访期间共有5例患儿出现晕厥复发,有效率79.2%。不同疗效的患儿治疗前心率、收缩压及基础肱动脉内径差异均无统计学意义,但治疗有效患儿治疗前FMD明显高于治疗无效患儿[(11.93±2.83)%VS(7.80±1.63)%,P<0.01]。采用ROC特征曲线评价FMD预测疗效灵敏度和特异度的结果显示,曲线下面积为0.895,95%置信区间为(0.764,1.026)。以FMD8.85%作为界值时,对疗效的预测效果较好,灵敏度90%,特异度80%。结论 FMD可作为VVS患儿选用盐酸米多君治疗的预测指标,界值为8.85%时具有较好的灵敏度和特异度。

Objective To investigate the predictive value of flow-mediated vasodilation （FMD） of brachial artery on therapeutic efficacy of midorine hydrochloride for vasovagal syncope （VVS） in children. Methods Twenty-four children with unexplained syncope underwent head-up tilt test and were diagnosed with VVS. All the patients received FMD detection and midodrine hydrochloride treatment. The patients were followed up in clinics after one month of treatment and repeated FMD detection was performed. After three months the patients were followed up by telephone. Twenty-four patients were followed up for 10 ~ 18 months, with a mean of （14.5 ± 2.3） months. The recurrence of syncope at the end of followed-up was used to evaluate the therapeutic efficacy. ROC curve was used to explore the predictive value of FMD. Results For 24 patients, FMD was reduced after one month treatment of midodrine hydrochloridc [ （ 11.07 -± 3.11 ）% vs （7.64 ± 1.81 ）%, P 〈 0.001 ] without any change in resting heart rate, resting systolic arterial pressure and baseline brachial artery diameters. During the follow-up period, 5 patients had recurrence of syncope. The effective rate of midodrine hydrochloride was 79.2%. There were no significant differences in resting heart rate, resting systolic arterial pressure and baseline brachial artery diameters before treatment between the patients with different therapeutic response. FMD in patients with good therapeutic efficacy was significantly higher than that with poor therapeutic efficacy [ （11.93 ± 2.83）% vs （7.80 ± 1.63）%, P = 0.005]. ROC curve on predictive value of FMD showed that area under curve was 0.895 with a 95% confidence interval of 0.22- 0.49, and a FMD of 8.85% as cutting value produced both high sensitivity （90%）and specificity （80%） to predict efficacy of midodrine hydrochloride for treating VVS. Conclusion FMD can be considered as an indicator for selecting midorine hydrochloride as a treatment for VVS in children. FMD of 8.85% taken as a cut-off value produces both high sensitivity and specificity.