Stent retriever

• Acute Distal Internal Carotid Artery Occlusion in Which Angiography during Mechanical Thrombectomy Revealed a Shunt between the Internal Carotid Artery and the Cavernous Sinus: A Case Report
• Types of stent retrievers used in mechanical thrombectomy for acute ischaemic stroke: A scoping review
• Stent-Retriever Thrombectomy in STEMI With Large Thrombus Burden: The RETRIEVE AMI Randomized Trial
• Does endovascular thrombectomy using super-bore 0.088" large distal platform offer advantages over balloon guide catheters in acute ischemic stroke secondary to large vessel occlusion?
• Early results with EmboTrap III stent retriever: A multicenter US experience
• Contemporary Results of Mechanical Thrombectomy and Impact of First-Line Technique on Outcome: The INSPIRE-S Global Registry
• Association between M1 tortuosity and intracranial hemorrhage after mechanical thrombectomy using a stent retriever for M2 occlusions
• Breaking the 12-hour barrier: A case report on stent-retriever mechanical thrombectomy in a late-presenting acute ischemic stroke

Stent retrievers, approved by the U.S. Food and Drug Administration in 2012, are tiny mesh tubes that grab and extract blood clots in blocked arteries

Stent retriever thrombectomy is the standard treatment for acute ischemic stroke (AIS) with large vessel occlusion (LVO) in the anterior circulation ¹⁾.

Stent retrievers are classified based on several factors, including their design, size, and the specific purpose of the procedure. Below is a general classification of stent retrievers:

1. Design and Mechanism of Action:

Single-Stent Retrievers: These devices consist of a single stent that is deployed inside the clot. The stent's structure is designed to capture and hold the clot when the device is retracted.

Double-Stent Retrievers: These devices have two stent-like structures designed to trap a larger clot or clots, improving the chances of complete clot retrieval in cases of larger occlusions. Double-stent retrievers can provide better clot engagement.

Self-Expanding Stent Retrievers: These stents are made of a material that expands when deployed in the blood vessel, helping to increase the surface area in contact with the clot for better engagement and retrieval.

2. Size and Diameter:

Stent retrievers come in various sizes to accommodate different arterial diameters and types of clot occlusions. The size is chosen based on the specific anatomy of the patient and the characteristics of the clot:

Small: These are used for smaller vessels or more delicate procedures.

Medium: A typical choice for most middle-sized arteries.

Large: Designed for larger vessels like the internal carotid or basilar arteries, where larger clot burdens may be present.

3. Material Composition:

Stent retrievers are made from different materials, often a combination of metals (such as nitinol) or polymers that offer flexibility and durability. Nitinol, a nickel-titanium alloy, is commonly used for its shape-memory properties, enabling the stent to expand and adapt to the clot.

4. Clinical Application:

Acute Ischemic Stroke Treatment: Stent retrievers are primarily used in thrombectomy procedures for the treatment of acute ischemic strokes, where they are deployed to retrieve blood clots that block blood flow to the brain.

Coronary Artery and Peripheral Vascular Use: Though primarily used in neurointervention, stent retrievers have also been explored for use in coronary and peripheral vascular procedures.

5. Deployment Mechanism: Manual Deployment: The stent is deployed manually, where the physician actively controls the expansion and retrieval process.

Automated or Catheter-Driven Deployment: Some systems are designed to allow for catheter-driven deployment and retrieval, giving the physician more control over the procedure.

6. Retrieval Method:

Proximal Retrieval: The retrieval mechanism begins at the proximal part of the clot (closer to the heart) and pulls the clot out, which is commonly used in most thrombectomy procedures.

Distal Retrieval: Some systems are designed to engage the clot from a more distal part of the occlusion, which can be useful in certain types of occlusions or when more precise clot removal is needed.

Several stent retrievers are currently used in mechanical thrombectomy (MT) to treat acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). These devices vary in design, performance, and specific applications. Below is an overview of notable stent retrievers:

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### 1. Solitaire™ FR (Medtronic) - Design:

1. Self-expanding nitinol stent.
2. Features a closed-cell design to ensure consistent clot engagement.

- Clinical Performance:

1. One of the most studied and widely used stent retrievers.
2. Demonstrated high recanalization rates (~85-90%) in clinical trials like SWIFT and SWIFT PRIME.

- Advantages:

1. Robust safety and efficacy data.
2. High first-pass efficacy and low risk of distal embolization.

- Applications:

1. Suitable for a variety of clot types and vessel anatomies.

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### 2. Trevo XP ProVue Retriever (Stryker) - Design:

1. Open-cell nitinol design with varying radial force along its length.
2. Radiopaque, allowing for real-time visualization under fluoroscopy.

- Clinical Performance:

1. Supported by trials like TREVO 2 and DAWN, which validated its safety and efficacy in MT.
2. Often favored for its ability to effectively remove large, firm clots.

- Advantages:

1. Effective in both anterior and posterior circulation strokes.
2. Low complication rates and high recanalization success (~86-90%).

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### 3. EmboTrap II (Cerenovus, Johnson & Johnson) - Design:

1. Dual-layer nitinol stent retriever designed to trap and remove thrombi while preserving endothelial integrity.

- Clinical Performance:

1. Demonstrates high rates of complete reperfusion and low rates of symptomatic intracranial hemorrhage.
2. Used in a variety of clinical settings, especially for fibrin-rich clots.

- Advantages:

1. Gentle clot retrieval, reducing vessel damage.
2. High rates of first-pass success.

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### 4. Capture L (Balt) - Design:

1. Braided nitinol stent retriever optimized for larger vessels.
2. Features a large distal section to capture and extract clots effectively.

- Clinical Performance:

1. Effective in treating LVOs in the anterior circulation.

- Advantages:

1. Specifically designed for larger clots and vessel diameters.

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### 5. Revive SE (Codman Neuro, Johnson & Johnson) - Design:

1. Laser-cut nitinol stent with a hybrid design combining open and closed cells.

- Clinical Performance:

1. Known for smooth deployment and consistent clot removal.

- Advantages:

1. Reliable for medium-to-large vessel occlusions.
2. Minimal risk of distal embolization.

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### 6. Aperio (Acandis) - Design:

1. Self-expanding nitinol device with unique strut configuration for clot integration.

- Clinical Performance:

1. Used in European stroke centers; preliminary data suggests efficacy similar to Solitaire and Trevo.

- Advantages:

1. Gentle on vessel walls, reducing complications.

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### 7. Tigertriever (Rapid Medical) - Design:

1. Adjustable stent retriever that allows physicians to control the device diameter during deployment.

- Clinical Performance:

1. Innovative adjustability enables customized engagement with clots, potentially improving outcomes.

- Advantages:

1. Real-time adjustability offers flexibility during thrombectomy.
2. High first-pass success rates.

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### 8. MindFrame Capture LP (Medtronic) - Design:

1. Miniature nitinol stent retriever designed for small vessels and distal occlusions.

- Clinical Performance:

1. Effective for smaller clots, especially in medium and distal vessels.

- Advantages:

1. Ideal for more challenging anatomies.
2. High safety profile.

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### Comparison of Stent Retrievers

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### Conclusion: The pRESET stent retriever joins a competitive field of devices, with Solitaire and Trevo serving as benchmarks due to their extensive data and consistent performance. Emerging devices like Tigertriever and EmboTrap II offer innovative solutions that may address specific challenges in clot retrieval. The choice of stent retriever often depends on individual patient characteristics, clot location, and physician preference.

Stent retriever for acute ischemic stroke treatment

Stent-Retriever for Cerebral Vasospasm Treatment