Stryker Acquires Inari Medical for $4.9B: Mechanical Thrombectomy, Venous Thromboembolism Device Market, and the $10B Endovascular Opportunity

Deal at a Glance

On January 6, 2025, Stryker Corporation (NYSE: SYK) announced a definitive agreement to acquire Inari Medical, Inc. (Nasdaq: NARI) for $80 per share in cash, representing a fully diluted equity value of approximately $4.9 billion. The all-cash tender offer closed rapidly — by February 19, 2025, Stryker had acquired approximately 81.69% of outstanding Inari shares and completed the second-step merger, making Inari a wholly owned subsidiary.

This is Stryker's largest acquisition since the $4 billion Wright Medical Group deal in 2020 ($5.4 billion including debt) and marks the company's decisive entry into the high-growth peripheral vascular and venous thromboembolism (VTE) device market. The acquisition creates a comprehensive interventional endovascular portfolio, combining Stryker's existing neurovascular business with Inari's mechanical thrombectomy platforms.

Deal Structure and Timeline

Stryker structured the acquisition as a two-step transaction: a cash tender offer for all outstanding Inari shares at $80 per share, followed by a second-step merger at the same price for any remaining shares. The merger entity, Eagle 1 Merger Sub, Inc., a wholly owned subsidiary of Stryker, was the acquisition vehicle.

The transaction moved with unusual speed for a deal of this size:

• January 6, 2025: Definitive agreement announced; Stryker commences tender offer
• February 18, 2025: Tender offer expires at 11:59 p.m. ET; 48,504,444 shares validly tendered (~81.69%)
• February 19, 2025: Stryker accepts tendered shares; second-step merger completed same day; Inari delisted from Nasdaq

The rapid closing was facilitated by the all-cash structure (no shareholder vote required), a clean regulatory review under the Hart-Scott-Rodino (HSR) Antitrust Improvements Act, and the tender condition requiring only a majority of outstanding shares.

Valuation Context

At $4.9 billion for a company generating approximately $603 million in 2024 revenue, Stryker paid approximately 8.1x revenue. This premium multiple reflects several factors: Inari's exceptional revenue growth trajectory (from $51 million in 2019 to $603 million in 2024, a compound annual growth rate exceeding 85%), the large and underpenetrated VTE market, Inari's dominant position in mechanical thrombectomy for PE and DVT, and the scarcity value of a high-growth, commercially scaled vascular device platform.

For context, Stryker's other major recent acquisitions include Wright Medical Group ($4 billion, 2020), Vocera Communications ($3 billion, 2022), and Sage Products ($2.8 billion, 2016). The Inari deal ranks among Stryker's largest transactions in its history of more than 60 acquisitions over the past decade.

Inari Medical: Company and Technology

Company Profile

Founded in 2011 and headquartered in Irvine, California, Inari Medical built its business on a single thesis: that mechanical thrombectomy — physically removing blood clots from blood vessels using catheter-based devices — could replace or supplement thrombolytic drug therapy as the standard of care for venous thromboembolism. The company's revenue growth has been remarkable:

Inari has treated more than 150,000 patients for VTE across 30+ countries, with products sold through a direct commercial organization focused on interventional radiologists, interventional cardiologists, and vascular surgeons.

FlowTriever System: Pulmonary Embolism

The FlowTriever Retrieval/Aspiration System is Inari's flagship product, designed for the treatment of pulmonary embolism (PE) — a condition in which blood clots travel to the lungs, potentially causing death. PE affects approximately 280,000 intermediate and high-risk patients annually in the United States.

The FlowTriever system enables minimally invasive, catheter-based removal of pulmonary emboli through a single-session procedure that does not require thrombolytic drugs. The device is delivered through a catheter inserted via the femoral or jugular vein, navigated to the pulmonary artery, where it mechanically extracts the clot using a combination of aspiration and mechanical engagement.

The drug-free approach is clinically significant: thrombolytic therapy carries a risk of major bleeding, including intracranial hemorrhage, which limits its use in many patients. Mechanical thrombectomy with FlowTriever eliminates this bleeding risk while achieving immediate clot burden reduction.

ClotTriever System: Deep Vein Thrombosis

The ClotTriever Thrombectomy System treats deep vein thrombosis (DVT) — blood clots that form in the deep veins, typically in the legs. Left untreated, DVT can lead to post-thrombotic syndrome (PTS), a chronic condition causing pain, swelling, and skin changes. The ClotTriever system removes venous thrombi through a mechanical, single-session approach, similarly avoiding the bleeding risks of thrombolytic drugs.

Emerging Products and Expansion Targets

Beyond PE and DVT, Inari is developing therapies for four additional disease states:

1. RevCore Thrombectomy Catheter: For in-stent thrombosis
2. InThrill Thrombectomy System: For arteriovenous fistula thrombosis (dialysis access management)
3. Chronic venous disease: Treating long-term venous insufficiency
4. Acute limb ischemia and chronic limb-threatening ischemia: Treating arterial blockages in the extremities

These expansion targets represent a combined $4 billion addressable U.S. market opportunity, layered on top of the $6 billion VTE thrombectomy market.

The VTE and Mechanical Thrombectomy Market

Disease Burden

Venous thromboembolism — encompassing both deep vein thrombosis and pulmonary embolism — affects up to 900,000 lives annually in the United States, according to the CDC. The condition is a leading cause of preventable hospital death, with patients at particularly high risk during or after hospitalization, cancer treatment, and pregnancy. Despite the significant disease burden, the vast majority of VTE patients are still treated with anticoagulation alone or with systemic thrombolytic drugs, leaving a large underpenetrated opportunity for mechanical thrombectomy.

Market Size and Growth

The mechanical thrombectomy market for VTE is growing at more than 20% annually, driven by expanding clinical evidence supporting interventional treatment over anticoagulation alone, increasing physician awareness, the establishment of dedicated reimbursement pathways, and the shift from thrombolytic drugs to device-based clot removal.

Competitive Landscape: The Two-Horse Race

Health Advances, a leading healthcare consulting firm, characterized the VTE thrombectomy market as a "two-horse race between Inari and Penumbra against thrombolytic therapy." This framing highlights the competitive dynamics:

Penumbra is Inari's primary device competitor. The company's Indigo aspiration platform competes directly in the mechanical thrombectomy space, though with a different technological approach (vacuum aspiration vs. Inari's mechanical engagement and extraction).

The competitive landscape also includes the broader shift from pharmacological treatment to device-based intervention. Thrombolytic therapy remains the established treatment for many VTE patients, but the bleeding risk, ICU stay requirements, and cost associated with lytic drugs are driving adoption of mechanical alternatives.

Regulatory Pathway

FDA Clearance for Thrombectomy Devices

Inari's thrombectomy devices were cleared through the FDA's 510(k) pathway for peripheral vascular applications. Mechanical thrombectomy catheters are classified as Class II devices under 21 CFR 870.1250 (Percutaneous Catheter). The regulatory pathway for these devices has become well-established, with predicate devices dating back to earlier aspiration and mechanical thrombectomy systems.

Key regulatory considerations for the thrombectomy market:

• Procedural reimbursement: Established procedural reimbursement codes exist for mechanical thrombectomy procedures, which has been a critical enabler of market adoption
• Clinical evidence: Inari has invested heavily in clinical research and program development to support its products, building an evidence base that validates mechanical thrombectomy as a standard of care
• Label expansion: As Inari/Stryker pursue new indications (chronic venous disease, dialysis access, limb ischemia), additional clinical data will be required to support FDA submissions

Strategic Implications

For Stryker

The Inari acquisition is transformative for Stryker's portfolio strategy. Kevin Lobo, Stryker's Chairman and CEO, articulated the rationale: "The acquisition of Inari expands Stryker's portfolio to provide life-saving solutions to patients who suffer from peripheral vascular diseases. These innovations elevate the standard of care for venous thromboembolism patients and will accelerate Stryker's impact in endovascular procedures."

Prior to the deal, Stryker's vascular presence was concentrated in neurovascular (stroke thrombectomy). The Inari acquisition adds a high-growth peripheral vascular franchise that is "highly complementary" to the existing neurovascular business, creating what Stryker calls a "comprehensive interventional endovascular portfolio."

The deal also reflects Stryker's proven M&A integration playbook. With more than 60 acquisitions completed over the past decade — including the transformative Wright Medical, Vocera, and Sage deals — Stryker has demonstrated the ability to acquire, integrate, and accelerate growth of acquired platforms.

For Inari Medical

Drew Hykes, Inari's CEO, described the strategic benefit: "With Stryker's capabilities and global infrastructure, we will be even better positioned to accelerate the development of innovative new solutions and expand our footprint." Access to Stryker's global commercial infrastructure, established relationships with hospitals and health systems, and capital resources positions Inari's technology for accelerated international expansion and faster development of emerging indications.

For the Competitive Landscape

The acquisition intensifies the competitive dynamics in several ways. Stryker's financial resources and global scale will likely accelerate Inari's expansion into the four emerging therapy areas, potentially widening the competitive moat against Penumbra. The deal also validates the VTE mechanical thrombectomy market as a major medtech opportunity, which could attract additional entrants and investment.

Frequently Asked Questions

What is venous thromboembolism (VTE)? VTE encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT occurs when blood clots form in deep veins, typically in the legs. PE occurs when clots break free and travel to the lungs. VTE affects up to 900,000 people annually in the US and is a leading cause of preventable hospital death.

What is mechanical thrombectomy? Mechanical thrombectomy is a minimally invasive procedure that uses catheter-based devices to physically remove blood clots from blood vessels. Unlike thrombolytic drug therapy, which dissolves clots chemically over hours or days and carries bleeding risks, mechanical thrombectomy removes clots in a single session without drugs.

What devices does Inari Medical make? Inari Medical's primary products are the FlowTriever system for pulmonary embolism and the ClotTriever system for deep vein thrombosis. Emerging products include the RevCore catheter for in-stent thrombosis and the InThrill system for dialysis access thrombosis.

How big is the mechanical thrombectomy market? The VTE thrombectomy market is estimated at approximately $6 billion in the US, growing at more than 20% annually. Including emerging indications (chronic venous disease, dialysis access, limb ischemia), the total addressable opportunity is approximately $10 billion.

Who are Inari Medical's main competitors? Penumbra is the primary device competitor in mechanical thrombectomy. Both companies compete against the established standard of thrombolytic drug therapy. Emerging competitors include Thrombolex, E2 Endovascular Engineering, and ICHOR Vascular.

Why did Stryker acquire Inari Medical? Stryker acquired Inari to enter the high-growth VTE and peripheral vascular device market, complement its existing neurovascular business, and create a comprehensive interventional endovascular portfolio. The deal also gives Stryker access to Inari's $10 billion total addressable market opportunity.