Heart surgery during pregnancy: Tracking the safety of a rare, sometimes unavoidable, scenario
Pregnant patients rarely undergo cardiac surgery, but it is unavoidable in certain clinical scenarios. To learn more about these uncommon occurrences, a team of Mayo Clinic researchers explored six decades of data from their institution, sharing their findings in The Annals of Thoracic Surgery.[1]
“Cardiac surgery during pregnancy is associated with morbidity or mortality for both mother and fetus; however, as cardiovascular surgical techniques, technology and obstetric care have advanced, the current maternal risk for cardiovascular surgery in pregnancy is reportedly similar to nonpregnant individuals,” wrote Katie T. Schmitz, MD, a physician with Mayo Clinic’s department of internal medicine, and colleagues. “For patients in whom medical management or less invasive techniques prove unsuccessful, expert opinion suggests the optimal timing of cardiopulmonary bypass (CPB) surgery to be the second trimester (14-28 weeks) because higher rates of maternal complications have been reported for procedures performed in the third trimester (28-42 weeks). Some studies support elective cesarean delivery before CPB surgery to minimize risk to the fetus if at a gestational age ≥26 weeks.”
Schmitz et al. examined data from 29 pregnant patients who underwent cardiac surgery using CPB at Mayo Clinic from 1978 to 2023. The median patient age was 28 years old and the median gestation was 25 weeks.
Surgery occurred during the first trimester for 10% of patients, during the second trimester for 55% and during the third trimester for the remaining 35%. The reason for surgery was aneurysm/dissection for 14% of patients, valve pathology for 55%, a thrombosed prosthetic valve for 14%, pulmonary embolism for 3%, endocarditis for 3% and “other” for 14%. The median CPB time was 53 minutes and median hospitalization lasted nine days.
Overall, maternal death after two weeks was quite low. In fact, it was only seen in 3% of patients—which translates to a single mother’s death. Fetal mortality, meanwhile, was seen in 17% of patients, though just two deaths occurred after 2011.
Focusing exclusively on the cases where there was a fetal death, researchers noted that the median bypass time was significantly longer than it was for cases that did not end in death, “suggestive of a relationship between complexity or extent of required cardiac surgical procedure and risk of loss.”
Schmitz and colleagues also highlighted the many factors that clinicians should take into account when determining the best course of action when pregnant patients may require cardiac surgery.
“Timing of CPB surgery and delivery are difficult and individualized decisions and should be based on maternal functional status, gestational age and shared decision making between patients and a multidisciplinary pregnancy heart team,” the authors wrote. “Current expert consensus indicates that the best timing for CPB surgery is the second trimester when the development of the fetus is largely complete. A recent study demonstrated that fetal mortality is lower when elective cesarean delivery is completed before CPB. In addition, fetal mortality was lower with elective cesarean section before CPB in the third trimester compared with the second trimester.”
Click here to read the team’s full analysis.
Additional details to consider about heart surgery during pregnancy
A separate editorial, also published in The Annals of Thoracic Surgery, reviewed key points related to the safety of performing cardiac surgery on pregnant patients.
“Valvular heart disease and aortic aneurysms / dissection are the most common pathologies in pregnant women requiring cardiac surgery,” wrote co-authors Marjan Jahangiri, MBBS, FRCS, and Basky Thilaganathan, MD, two specialists with the University of London. “The valvular pathologies in women of childbearing age are most commonly congenital, but may include rheumatic, acquired, and native degenerative causes. Women with a history of valvular heart disease should undergo preconception evaluation by the cardio-obstetric team. The overall risks and benefits should be discussed before pregnancy.”
Jahangiri and Thilaganathan also noted that many patients with asymptomatic heart disease become symptomatic over the course of their pregnancies.
“Echocardiographers and magnetic resonance imaging specialists should take these physiologic changes into account when interpreting images during pregnancy and assessing progression of disease,” the two co-authors explained. “Severe aortic stenosis can result from bicuspid aortic valve, degenerative tricuspid valve, or rheumatic disease. It is associated with increased maternal and fetal risk during pregnancy, including heart failure, arrhythmias and death. Due to reduced forward flow, risks to the fetus include prematurity and reduced growth.”
In addition, the duo repeated a point made by Schmitz et al. in their own analysis: cesarean delivery prior to CPB should be considered whenever possible.
“If the fetus is thought not viable and maternal condition is stable, cardiac surgery should be postponed allowing safe delivery of the fetus through cesarean section later,” they wrote. “Cardiac surgery could also be performed postpartum, if the mother remains stable.”
Click here to read the full editorial.
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.