[Predictive value of upright blood pressure change for long-term prognosis of children with postural tachycardia syndrome treated with midodrine hydrochloride].

Objective: To explore the predictive value of upright blood pressure change for long-term prognosis of children with postural tachycardia syndrome (POTS) treated with midodrine hydrochloride.
Method: A total of 90 children (male 41, female 49) were enrolled in this study. Their mean age was (11.8±2.7) years. They were diagnosed as POTS in Peking University First Hospital from 2005 to 2011. According to the upright change of blood pressure at the first visit, they were divided into two groups, effective group (n=55) and ineffective group(n=35). The follow-up time was 53-130 months. The orthostatic intolerance symptom score and symptom free survival rate were compared between the two groups.
Result: The change of systolic blood pressure and of diastolic blood pressure was lower in effective group than those in ineffective group (0(-6, 0) mmHg (1 mmHg=0.133 kPa) vs. 9(6, 11) mmHg, Z=-8.303, P<0.01; 0(0, 5) mmHg vs. 11(10, 16) mmHg, Z=-7.058, P<0.01). Two groups had no significant difference in symptom scores before treatment((4.8±0.9) points vs. (5.0±0.8) points, t=-0.53, P=0.595), while symptom scores were lower in effective group than that in ineffective group((1.3±0.9) points vs. (4.7±0.9) points, t=-15.60, P<0.01 ). The symptom free survival rate was higher in effective group than that in ineffective group (48/55(87.3%) vs. 23/35(65.7%), χ(2)=5.969, P<0.01).
Conclusion: The upright change of blood pressure has a good predictive value on the long-term survival of POTS children treated with midodrine hydrochloride.