Boston Scientific Invests in MiRus With Option to Acquire TAVR System

May 21, 2026—Boston Scientific announced it has invested $1.5 billion in MiRus LLC, in return for an approximately 34% equity stake in the company.

MiRus is a privately held company developing and commercializing biomaterials, implants, and procedural solutions for the treatment of cardiovascular and orthopedic diseases, including the Siegel balloon-expandable transcatheter aortic valve replacement (TAVR) system, stated Boston Scientific.

The press release advised that as part of the investment agreement, Boston Scientific also received an exclusive option to acquire MiRus’s TAVR system, subject to additional payments and the completion of certain milestones.

Boston Scientific noted that it may exercise the option to acquire the MiRus TAVR business by making additional aggregate cash payments totaling $3 billion, which would result in 100% ownership of the TAVR business, subject to customary closing conditions.

If Boston Scientific exercises the option, MiRus will have the right to receive additional payments based on net sales of the Siegel TAVR valve over a specified period and the company will also have an exclusive option to acquire mitral and tricuspid replacement valve assets from MiRus for an additional payment, stated Boston Scientific.

The Siegel TAVR system is a nickel-free device built on MiRus’s rhenium alloy in three sizes—23 mm, 26 mm, and 29 mm—that can be delivered through an 8-F expandable sheath. The Siegel TAVR system is an investigational device, which is not yet approved for commercial distribution in any country, advised the company.

The Boston Scientific press release further noted that MiRus recently initiated the STAR pivotal trial that is evaluating the safety and effectiveness of the three sizes of the Siegel valve in up to 1,025 patients with severe, symptomatic aortic stenosis considered to be at low, intermediate, or high risk for surgical complications. In 2025, MiRus announced the presentation of findings from the United States early feasibility study assessing the safety and performance of the Siegel device.