Prevalence of Congenital Heart Disease at Extremely High Altitudes in Tibet and the Establishment of a New Free Treatment Model

Background: This study aimed to illustrate the prevalence of CHD by screening children in extremely high-altitude areas (over 4000 m to even 5000 m above sea level) and explore an aid model for early diagnosis and treatment for the Tibetan population. Methods: A total of 2242 students from different schools in Ngamring County, Xigaze City, Tibet from September 2019 to September 2020 were selected for screening. The students were examined through the inquiry of their current medical history and family history, cardiac auscultation and a physical examination, in order to screen out the suspected cases of CHD, and then the suspected cases were confirmed by cardiac color ultrasound examinations. After that, positive patients were be transferred to Shandong Province for free treatment. Results: The prevalence of CHD among children in Ngamring County was 3.70% (83 cases), which is the highest incidence rate ever reported. The most common type of CHD was patent ductus arteriosus (PDA), accounting for 55.42% of the total number of cases screened, followed by atrial septal defect (ASD) and ventricular septal defect (VSD), accounting for 28.92% and 12.05%, respectively. The prevalence of CHD in children at high altitude was significantly higher than that in children at low altitude. The children with CHD were transferred to Shandong Province for surgery, the operations were successful and their recoveries went well. Conclusions: The results show that high altitude is closely related to the prevalence of CHD, and the incidence in Ngamring County is much higher than that in previous reports.