Difference between Supine and Upright Blood Pressure Associates to the Efficacy of Midodrine on Postural Orthostatic Tachycardia Syndrome (POTS) in Children

Abstract

Postural orthostatic tachycardia syndrome (POTS) is common, and has a serious impact on children's quality of life. Midodrine hydrochloride, an α1-adrenoreceptor agonist, is an effective treatment. The study was designed to examine the therapeutic efficacy of midodrine hydrochloride by quantifying changes in blood pressure during the head-up test (HUT), in children with POTS. Overall, 104 out of 110 children with POTS were treated with midodrine hydrochloride and successfully followed-up. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) changes were analyzed during the HUT. In a retrospective analysis, a receiver operating characteristic (ROC) curve was used to analyze the therapeutic predictive value of pre-treatment changes in SBP, DBP, and a combination of both, from the supine position to standing, in the subjects. The increase of SBP and DBP from the supine position to standing in responders were significantly lower than that of the non-responders. The ROC curve showed that midodrine hydrochloride for children with POTS would be predicted to be effective when the pre-treatment increase of SBP was ≤ 0 mmHg, or when the pre-treatment increase of DBP was ≤ 6.5 mmHg (from the supine position to standing), yielding a sensitivity of 72% and specificity of 88%. The area under the curve was 0.744 and 0.809, respectively. Hence, the results suggested that looking at the changes in blood pressure during the HUT was useful in predicting the response to midodrine hydrochloride in children with POTS.

2018 Chinese Pediatric Cardiology Society (CPCS) guideline for diagnosis and treatment of syncope in children and adolescents

“…Midodrine hydrochloride is effective for some forms of pediatric POTS [46][47][48][49][50][51]. The initial dose usually is 2.5 mg once or twice a day, with an increase to 2.5 mg three times a day, as necessary [46][47][48][49][50][51]. BP should be monitored during the treatment.…”

“…Hemodynamic indexes and biomarkers are useful for drug selection. Midodrine hydrochloride is indicated with flow-mediated dilation >9.85% [49], hydrogen sulfide production from erythrocytes >27.1 nmol/min [50], plasma midregional proadrenomedullin level >61.5 pg/mL [51], plasma copeptin level >10.5 pmol/L [46], pre-treatment increase of SBP 0 mmHg, or pre-treatment increase of DBP 6.5 mmHg (from the supine position to standing) [47] but with BP greater than the 95th percentile BP value by age and sex or with drug allergy (IIa; B).…”

Pathogenesis and Individualized Treatment for Postural Tachycardia Syndrome in Children

“…To find out a simple and noninvasive method to select the responders to the midodrine treatment, Deng et al . [ 33 ] tried to analyze the usefulness of blood pressure change from supine to upright before treatment to predict the effectiveness of midodrine on POTS in children. They found that children with POTS would respond well to midodrine when the pretreatment increase of systolic blood pressure was ≤0 mmHg (1mmHg=0.133kPa), or when the pretreatment increase of diastolic blood pressure was ≤6.5 mmHg (from the supine position to upright), with a sensitivity of 72% and specificity of 88%.…”

Assessment of therapeutic biomarkers in the treatment of children with postural tachycardia syndrome and vasovagal syncope

“…In 2013, Deng et al found that midodrine hydrochloride for children with postural tachycardia syndrome would be predicted to be effective when the pre-treatment increase in systolic blood pressure was ⩽0 mmHg, or when the pre-treatment increase in diastolic blood pressure was ⩽6.5 mmHgfrom the supine position to standingyielding a sensitivity of 72% and specificity of 88%. 38 Haemodynamic change during head-up tilt test as a predictor for the therapeutic response to β-adrenoceptor blocker in children with vasovagal syncope…”