肺动脉高压常见于先天性心脏病，新生儿持续肺动脉高压，缺氧性疾患（如支气管哮喘、婴幼儿肺炎、高原性心脏病及支气管发育不良等）和特发性肺动脉高压。最常见的症状是活动后气急和乏力；晕厥也是常见的表现。严重者可导致右心室负荷增大、右心功能不全，引起一系列临床表现。儿童肺动脉高压血流动力学定义为： 在海平面静息状态下， 右心导管测定肺动脉平均压(mPAP)高于25 mm Hg， 肺毛细血管楔压（PCWP）低于或等于15 mm Hg或肺血管阻力（PVR）大于3 Wood单位。治疗主要包括综合治疗,如强心、利尿、吸氧和抗凝等,并根据急性肺血管扩张试验结果选择血管扩张剂治疗或外科治疗。
Hydroxyurea is an effective treatment for sickle cell anemia, but few studies have been conducted in sub-Saharan Africa.
Children 1 to 10 years of age with sickle cell anemia received hydroxyurea at a dose of 15 to 20 mg per kilogram of body weight per day for 6 months, followed by dose escalation.
The retention rate was 94.2% at 3 years of treatment.
Hydroxyurea therapy led to significant increases in both the hemoglobin and fetal hemoglobin levels.
Dose-limiting toxic events occurred in 5.1% of the participants, which was below the protocol-specified threshold for safety.
As compared with the pretreatment period, the rates of clinical adverse events decreased with hydroxyurea use, including rates of vaso-occlusive pain (98.3 vs. 44.6 events per 100 patient-years), nonmalaria infection (142.5 vs. 90.0 events ), malaria (46.9 vs. 22.9 events), transfusion (43.3 vs. 14.2 events ), and death (3.6 vs. 1.1 deaths）
Hydroxyurea treatment was feasible and safe in children with sickle cell anemia living in sub-Saharan Africa.
Hydroxyurea use reduced the incidence of vaso-occlusive events, infections, malaria, transfusions, and death, which supports the need for wider access to treatment. （2019nejm0110-0110-0305）