CLINICAL PRACTICE FOR ACUTE VASOREACTIVITY TESTING IN PEDIATRIC PULMONARY ARTERIAL HYPERTENSION IN REAL-WORLD

TYPE: Abstract TOPIC: Pediatrics PURPOSE: To evaluate how acute vasoreactivity testing (AVT) and long-term high-dose calcium channel blockers (CCBs) actually work for responders in pediatric pulmonary arterial hypertension (PAH) in real-world. METHODS: Children who were diagnosed idiopathic/heritable PAH from 2006 to 2020 in FuWai hospital were retrospectively analyzed to explore the characteristics of AVT responders, the detailed CCB regimens, and long-term survival for different responsiveness to AVT in the contemporary treatment era. RESULTS: Of 151 children who were confirmed idiopathic/heritable PAH, 33 were acute responders to AVT and 118 non-responders. Responders and nonresponders were followed at a median period of 6.1 years and 4.9 years. Thirty-two (97.0%) responders were initially treated with diltiazem, with the median maximum dose reaching to 330mg/per day (240-420mg/per day) and the median duration for dose uptitration was 24 weeks (18-30 weeks). All but one acute responder were alive with WHO functional class I or II, however, for the nonresponders, the median survival was 9.5 years, and the 1-, 5-, 10-year transplantation-free survival rates were 93.2±2.3%, 73.9±4.8%, 43.6±9.9%. Side effects for the high-dose diltiazem occurred in 77.4% of children, gingival hyperplasia (16/31) and increase in body hair (9/31) were the most frequently reported CONCLUSIONS: Proper administration of chronic high-dose CCB worked well for the long-term responders defined under the current guideline with mild to moderate side effects. Nevertheless, the long-term survival for nonresponders did not seem to improve significantly compared to that reported five to ten years ago CLINICAL IMPLICATIONS: Chronic use of high dose CCB was proved effective and safe for the pediatric responders of PAH in real practice DISCLOSURE: Nothing to declare. KEYWORD: pediatric pulmonary arterial hypertension