Boston Scientific expands structural heart push with US$1.5B MiRus TAVR investment

USA—Boston Scientific has announced a US$1.5 billion investment to acquire a 34% stake in MiRus, a medical technology company developing the SIEGEL balloon-expandable transcatheter aortic valve replacement (TAVR) system.

This agreement also grants Boston Scientific an exclusive option to acquire the TAVR programme, subject to additional payments and to clinical and regulatory milestones.

The investment strengthens Boston Scientific’s cardiovascular portfolio as it continues to expand into structural heart therapies.

Under the terms, the company may acquire full ownership of MiRus’ TAVR business for an additional US$3 billion upon achieving defined milestones, reinforcing its long-term focus on minimally invasive heart valve replacement technologies.

SIEGEL TAVR system design and technology

The SIEGEL valve features a rhenium alloy frame and is the first nickel-free balloon-expandable TAVR system designed to restore blood flow in patients with severe aortic stenosis.

It integrates dry porcine tissue leaflets with a nitric oxide-coated rhenium structure, delivering higher radial strength than cobalt- or titanium-based platforms.

Its open-cell design supports improved anatomical conformity, helping reduce foreshortening and enabling more precise placement during implantation procedures.

Delivery system and procedural efficiency

The system is engineered to be delivered in 23mm, 26mm, and 29mm sizes using an 8-Fr expandable sheath.

This delivery profile is nearly 50% smaller than many current commercial TAVR systems, potentially lowering the risk of vascular complications.

The reduced sheath size also enhances maneuverability through challenging vascular pathways, offering clinicians improved flexibility during complex structural heart interventions.

STAR pivotal trial and expansion pathway

MiRus has launched the STAR pivotal trial, which will enroll up to 1,025 patients with severe, symptomatic aortic stenosis across a range of surgical risk categories.

The study builds on earlier feasibility results presented last year and will evaluate both the safety and performance of the SIEGEL system across multiple valve sizes.

In addition to the TAVR program, Boston Scientific retains the option to expand its acquisition scope to include MiRus’ mitral and tricuspid valve technologies, depending on future development and regulatory progress.

Executive perspective on market growth

Lance Bates, executive vice-president and president of Boston Scientific’s interventional cardiology and vascular therapies division, highlighted the rising global burden of aortic stenosis and the need for advanced treatment options.

He stated that the investment reflects the company’s strategy to introduce differentiated TAVR technologies into its portfolio.

He further emphasized that early clinical data and the system’s proprietary design could position the SIEGEL valve as a distinctive option for physicians managing a broad range of complex patients.

Regulatory progress in adjacent technologies

In a separate development, Boston Scientific secured 510(k) clearance from the US Food and Drug Administration in March 2026 for its Asurys fluid management system.

The platform supports irrigation and distention during endoscopic urologic procedures, including ureteroscopy, strengthening the company’s portfolio of minimally invasive procedural solutions.