Women with pulmonary arterial hypertension (PAH) secondary to congenital heart disease (PAH-CHD) are at a high risk of heart failure, pulmonary hypertensive crisis, or even death during pregnancy, a study reports.
Those at a higher risk appeared to be women with PAH who also had advanced heart disease, called Eisenmenger syndrome, or who had their heart defects corrected.
Preconception counseling is strongly advised for these women, as well as close monitoring throughout their pregnancy, especially in the days prior to or just before delivery, the researchers said.
The study with these findings, “Peripartum outcomes in a large population of women with pulmonary arterial hypertension associated with congenital heart disease,” was published recently in the European Journal of Preventive Cardiology.
PAH caused by congenital heart disease is a serious complication that brings additional risks to pregnant patients. During pregnancy, women’s blood volume — the amount of blood that needs to be pumped from the heart — increases from 30% to 50% compared with the normal amount, putting increased stress on the organs and circulatory system.
In this study, a team of researchers at Beijing Anzhen Hospital in China analyzed a variety of clinical presentations, maternal outcomes, and risk factors for pregnant women with PAH, around the time of childbirth (just before or after delivery, i.e., the peripartum period). The study included 93 women with an average age of 27.5 years.
A little more than half (54.3%) had PAH associated with systemic-to-pulmonary (i.e., left-to-right) shunts — a hole in the heart that causes blood from the left side of the heart to go to the right side.
Nearly one-third (31.9%) had Eisenmenger syndrome (ES), the most advanced disease, due to heart shunts. In these patients, the blood pressure in the lungs becomes so high that blood starts to flow in the reverse direction, causing oxygen-poor blood to be pumped into the body, reducing the amount of oxygen that reaches organs and tissues.
The remaining women, 13.8%, had received surgery to correct their CHD defect.
About half (54.2%) had to take PAH medications during pregnancy, and 24.5% required admission to the hospital two days before delivery.
Nearly all (95.7%) gave birth through a planned (or elective) Caesarean section.
A substantial number of women had a poor outcome: six (6.4%) women died, 33 (35.1%) developed heart failure, and 10 (10.6%) had a pulmonary hypertensive crisis.
Researchers also looked at potential factors that could be associated with and predict these adverse outcomes, finding that women who had these complications (36.2%) were more likely to have Eisenmenger syndrome or repaired heart defects.
Other factors associated with a higher likelihood of complications included low blood oxygen (which causes cyanosis), higher brain natriuretic peptide (BNP; a biomarker of heart failure), and accumulation of fluid around the heart (pericardial effusion) identified by an echocardiogram (ultrasound).
Fetal or neonatal complications occurred in almost half of the babies born to women with ES (46.7%), in 19.6% of those with left-right shunts, and in 15.4% of patients with repaired defects.
“This article presents the largest single center experience of patients with PAH-CHD giving birth to date,” the researchers said.
Mortality in this group of patients was lower than previously reported, but still significantly worse than in the general population.
In total, 16.7% of the women with ES and 7.7% of the women with corrected heart defects died, while none with left-to-right shunts died.
The number of fatalities in the first two groups may have been even higher, as the study did not address women who may have died earlier in their pregnancies.
Most deaths happened within hours or days following delivery, “underlining the importance of close monitoring for several days after delivery,” the researchers wrote.
Prior studies have indicated that severe PAH and cyanosis are associated with “the greatest maternal mortality and morbidity, and pregnancy should be discouraged in all such cases,” the authors said, adding that “pre-conception counseling is important and pregnancy should be advised against in most [PAH-CHD] cases, offering appropriate advice on contraception.”
If women still decide to move forward with a pregnancy, they should be placed under appropriate tertiary care, and with the use of PAH therapies.
Careful delivery planning also is essential, the researchers said, recommending “a large multi-disciplinary team (including obstetricians, cardiologists, anesthetists, neonatologists) and the patient.”
Women at a higher risk of complications — including those with a high BNP, low blood oxygen, and pericardial effusion — should remain “under very close monitoring” the researchers advised, adding that a late diagnosis and urgent referral to the hospital close to delivery likely increases the chances of death or other complications for both mother and child.