Maternal Death Due to Pulmonary Arterial Hypertension - A Nationwide Survey in Japan.

Background: With advances in treatment, the prognosis for pregnancies complicated by pulmonary arterial hypertension (PAH) has been improving. However, PAH-related maternal mortality remains high compared with that due to other cardiovascular diseases. The specifics of PAH-related maternal deaths under advanced medical standards are not well understood.

Methods and results: We used the maternal death registration system established by the Japan Association of Obstetricians and Gynecologists and reviewed 6 PAH-related maternal deaths from 2010 to 2022. All women were initially diagnosed with PAH during pregnancy or immediately after childbirth. The diagnosis of PAH tended to be delayed because symptoms were not reported to healthcare providers and/or a different disease was diagnosed. Cardiogenic shock occurred antepartum in 1 woman and during delivery or within 7 days after delivery in the other 5 women. Four women were resuscitated and started on extracorporeal membrane oxygenation. Pulmonary vasodilators were initiated in 4 women, with a median duration of 8 days from PAH diagnosis to starting medication. Right heart failure was the most common cause of maternal death, with a median duration of 16 days from PAH diagnosis to maternal death.

Conclusions: All PAH-related maternal deaths occurred in women who were diagnosed with PAH after pregnancy. Diagnosing PAH and initiating pulmonary vasodilators takes considerable time, highlighting the importance of early diagnosis and early treatment.