Study Warns TAVR Implants May Increase Hemolysis Risks

Researchers have found that numerous factors may be at play between TAVR and hemolytic anemia, including mild and even trace level valve leaks.

A new study warns that the most advanced valves used in transcatheter aortic valve replacement (TAVR) may be causing the destruction of healthy red blood cells, which could cause patients to develop anemia and other complications.

The findings were outlined by Japanese researchers in a report published in the Journal of the American College of Cardiology (JACC): Asia on January 12, warning that they have seen an increase in reports of hemolytic anemia (HA) linked to fifth-generation SAPIEN 3 Ultra RESILIA (S3UR) valves, when compared to older models, such as the third-generation SAPIEN 3 (S3).

TAVR is a procedure where the heart valve is replaced by threading it through an artery in the leg instead of via open chest surgery. It places the valve directly over the damaged aortic valve in a less invasive procedure, leading to it being favored by many doctors.

Previous studies have linked TAVR valve implants to serious complications, including an increased risk of death, rapid valve deterioration and the need for additional surgeries, with some research also indicating a heightened risk of end-stage kidney disease.

Other studies have linked TAVR surgery to an increased risk of endocarditis, a serious inflammation of the lining of the heart and heart valves. That data indicated patients undergoing TAVR surgery faced nearly double the risk of death.

For the study, researchers at Japan’s National Cerebral and Cardiovascular Center reviewed outcomes for 230 patients who underwent transcatheter aortic valve replacement, comparing those implanted with the newer SAPIEN 3 Ultra RESILIA valve to patients who received the older SAPIEN 3 model. The researchers focused on whether patients developed hemolytic anemia, a condition caused when red blood cells are damaged or destroyed as they pass through an artificial heart valve.

Hemolytic anemia can occur when blood is forced through narrow gaps or turbulent flow around a valve, causing red blood cells to rupture. When this process happens repeatedly, the body cannot replace the damaged cells fast enough, leading to anemia and symptoms such as fatigue, weakness and shortness of breath.

The newer S3UR valve includes several design changes intended to improve performance, including a significantly taller outer sealing skirt designed to reduce blood leakage around the valve, known as paravalvular leak. It also uses a different type of treated cow tissue for the valve leaflets, which is intended to slow wear and calcification over time. However, the researchers noted that even small leaks around heart valves have long been associated with hemolysis in both transcatheter and surgically implanted valves.

According to the study’s findings, 10 of the 117 patients who received the newer S3UR valve developed hemolytic anemia, compared to just one of the 113 patients implanted with the older S3 valve. The researchers reported no major differences in how the procedures were performed between the two groups, suggesting the higher rate of hemolysis was not explained by surgical technique alone.

“We report that although there were no remarkable differences in procedural details, including final inflation volume, predilatation or postdilatation, and oversizing rate, and annular calcification was more severe in the S3 group than S3UR, the incidence of HA was significantly higher in S3UR than in S3.”

— Shinichi Kurashima, Hemolysis After TAVR Using the Fifth-Generation Balloon-Expandable Valve: Comparison With the Third-Generation Valve

The researchers concluded that patients who received the newer valve faced a higher risk of hemolytic anemia, particularly those with severe calcification around the valve opening, those undergoing dialysis, or those who received smaller valve sizes. 

They cautioned that multiple factors are likely involved, but said the findings raise concerns that certain design changes intended to improve valve performance may also increase the risk of blood damage in some patients.

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