Steffi Thiem, 31, and Cassi Oshefsky, 27, share more than a sisterly bond — they have the same congenital heart defect. Steffi and Cassi, of Denmark, Wisconsin, were both born with a bicuspid aortic valve, an abnormality that affects how blood flows between the heart and the aorta. They had surgery to replace their faulty aortic valve with a mechanical heart valve, but this presented some risks when they decided to start their families. 

“We both knew we were going to be dealing with high-risk pregnancies,” Cassi said. “Having each other’s support, especially because we were pregnant with our kids at the same time, was such a blessing.”

Replacing a Bicuspid Aortic Valve with a Mechanical Heart Valve

A normal aortic valve has three cusps or leaflets. The cusps open and close, allowing blood to leave the heart and go out to the body. In some people, two cusps develop instead of three, which can lead to problems with the valve opening and closing. This may cause blood to leak backwards into the heart (aortic regurgitation) or limit the amount of blood that can flow out to the rest of the body (aortic stenosis.) People can live with a bicuspid aortic valve for many years without developing symptoms, but over time, they may notice chest pain, heart palpitations, shortness of breath, fatigue and dizziness.

Cassi was diagnosed with a bicuspid aortic valve at birth. Steffi was diagnosed when she was 17; she found out after her pediatrician found a murmur during a routine physical. Between 2013 and 2014, symptoms for both sisters had progressed to the point where they needed surgery to replace their aortic valves. They chose a mechanical valve over a tissue valve. They made this choice because a mechanical heart valve is more durable, but it meant they would have to be on a daily dose of a blood thinner called warfarin for the rest of their lives in order to prevent clots.

“Even for a woman with a healthy heart, the heart is under more stress during pregnancy because it’s working harder,” said Meredith Cruz, MD, Froedtert & MCW maternal fetal medicine physician. “There are also hormones during pregnancy that can increase the risk of a clot. For a woman with valve disease or with a mechanical heart valve who is on blood thinners, the risk is much higher.”

Managing Mechanical Heart Valves During Pregnancy

Cassi and Steffi each have three children, all a few months apart in age. When they were pregnant with their first daughters, their local obstetrician immediately referred them to the team of experts with the Froedtert & MCW Heart Disease in Pregnancy Program. The program is made up of specialists in adult congenital heart disease, cardiology, maternal fetal medicine, obstetrics and anesthesiology. The team coordinated with Steffi’s and Cassi’s local physicians in the Green Bay area and provided guidance for successful labor and delivery plans. The most important consideration was how to balance the mother’s health with the baby’s health.

“We monitor and adjust the mother’s anticoagulant therapy throughout her pregnancy in a way that allows us to minimize the risk of a clot while protecting the fetus’ development,” said Scott Cohen, MD, Froedtert & MCW congenital heart disease cardiologist. “Warfarin is generally avoided during pregnancy because of the drug’s ability to cross over into the placenta, so we transitioned both women to enoxaparin sodium, also known as Lovenox®, during their pregnancies. When they were admitted, they were put on heparin, which is safer for labor.”

Dr. Cohen worked with Steffi’s and Cassi’s doctors in Green Bay to monitor their bloodwork throughout their pregnancies. They were also able to see him in person for appointments in Green Bay. In addition to his role within the Froedtert & MCW health network, Dr. Cohen is the program director of the Adult Congenital Heart Disease Program within the Herma Heart Institute at Children’s Wisconsin. This means he cares for patients in specialty clinics across the state, including Green Bay, Fond du Lac, Appleton, Kenosha, Delafield and Iron Mountain, Michigan. Steffi and Cassi only had to drive the 100 miles from their homes to the Froedtert Hospital campus twice for each pregnancy — once to meet with their whole care team and the second time to deliver their babies. 

“It was all very convenient,” Steffi said. “I loved how my Froedtert doctors stayed in communication with my doctors at home. And when I did have to drive to Milwaukee, it was well-organized, the team scheduled all of our providers in one day; they made sure we had directions and that we were comfortable. I felt like I was in very good hands.”

Giving Birth With a Mechanical Heart Valve

When it came time to deliver, Steffi and Cassi were admitted to Froedtert Hospital a week in advance so their care team could manage and monitor their transition to different blood thinners and prepare for their deliveries. Steffi and Cassi switched from enoxaparin sodium injections to a heparin drip, which needed to be stopped as soon as their contractions began to manage bleeding risks. Steffi delivered all three of her children via C-section while Cassi had three vaginal births. 

“We generally recommend vaginal births for our patients with congenital heart disease because a C-section comes with its own risks, but in Steffi’s case this wasn’t possible for obstetric reasons,” Dr. Cohen said. “This is an example of how the collaboration and expertise of our team is so important, as we work to keep mom and baby healthy, despite complications.” 

Thanks to the coordinated care between the Froedtert & MCW health network and Children’s Wisconsin, each of Steffi’s and Cassi’s children had an echocardiogram shortly after birth. The echocardiogram shows how the heart and valves are functioning, which is important due to their children’s increased risk of congenital heart disease. All of Cassi’s children were born healthy, but Steffi’s second child was diagnosed with a bicuspid aortic valve at birth. 

“It was emotional, but I’m so relieved to have access to all of the physicians in one place and to be able to get the information about my son’s condition early on,” Steffi said. “We’ll be doing yearly echocardiograms at Children’s Wisconsin and monitoring him for any possible symptoms as he gets older.”

Both sisters recovered well from birth and were discharged with their new babies without any complications. In the weeks that followed, they saw their local physicians for follow-up care while continuing to have their labs monitored by their Froedtert & MCW Heart Disease and Pregnancy Care team. Both say they’re grateful for the expertise and support from all of their providers during such an emotional and life-changing time for their families.

“They took amazing care of us,” Cassi said. “They made us feel comfortable, made sure everything went smoothly and explained it all so well as we went along. We couldn’t have done this without them.”

Learn more about the Froedtert & MCW Heart Disease in Pregnancy Program.