Covered Flow Diverters for Aneurysm Treatment: A Breakthrough in Endovascular Therapy

Covered flow diverters for aneurysm treatment are advanced endovascular devices that improve patient outcomes by accelerating vessel healing, reducing complications, and shortening recovery time. This article explores how these devices use specialized covering technologies—including polymeric, bioactive, and drug-eluting layers—to enhance the treatment of intracranial aneurysms and other vascular disorders.

By the end of this article, you’ll understand why covered flow diverters are becoming a cornerstone in modern aneurysm management.

What Are Covered Flow Diverters?

Covered flow diverters for aneurysm treatment are stent-like devices inserted into blood vessels to redirect blood flow away from aneurysms. They are commonly used for:

• Intracranial aneurysms (especially large or wide-necked)

• Arteriovenous malformations (AVMs)

• Carotid-cavernous fistulas (CCFs)

Unlike traditional coiling techniques, covered flow diverters focus on long-term vessel remodeling, making them highly effective for complex aneurysm treatment. Learn more about endovascular devices and procedures.

Benefits of Covered Flow Diverters for Aneurysm Treatment

Adding coverings to flow diverters provides several advantages:

• Accelerated endothelialization – faster regrowth of the vessel lining

• Improved biocompatibility – reduced inflammation and clotting risks

• Higher aneurysm occlusion rates – better long-term closure

• Shorter patient recovery – fewer complications and quicker stabilization

• Reduced hospital stays – lower healthcare costs

For additional clinical insights, see this review on aneurysm treatment outcomes (outbound link).

Covering Technologies in Flow Diverters

Different coatings enhance the performance of covered flow diverters for aneurysm treatment:

Polymeric Coatings

Polyurethane, polycarbonate urethane (ChronoFlex®), and fluoropolymers provide controlled porosity and smooth surfaces to support faster vessel healing.

Bioactive Coatings

Incorporating extracellular matrix proteins, adhesion peptides, or growth factors stimulates natural tissue regeneration.

Drug-Eluting Coatings

Controlled release of agents like sirolimus or heparin prevents thrombosis and promotes endothelialization.

Hybrid Approaches

Combining polymeric, bioactive, and drug-eluting strategies maximizes device performance.

Challenges of Covered Flow Diverters for Aneurysm Treatment

Despite their promise, covered flow diverters for aneurysm treatment face challenges:

• Maintaining flexibility and deliverability despite additional layers

• Ensuring long-term durability without delamination or degradation

• Meeting regulatory and clinical validation requirements

Ongoing research in biomaterials and coatings is helping to overcome these limitations. For more information, see our vascular device research page.

Conclusion: The Future of Aneurysm Treatment

Covered flow diverters for aneurysm treatment represent a breakthrough in endovascular therapy. By reducing the time to full therapeutic effect, these devices improve patient outcomes, shorten recovery time, and decrease hospital stays. As innovations in covering technologies continue, these devices are poised to become a cornerstone in the treatment of intracranial aneurysms and complex vascular pathologies.

👉 Stay updated on advanced covering technologies and the latest in vascular device innovation by following our blog.

Expandable sheaths are reshaping minimally invasive medicine. By allowing larger devices to be delivered through smaller access sites, they make procedures safer and recovery faster. Once limited to a handful of uses, these devices are now expanding into new clinical fields—improving outcomes for patients, surgeons, and healthcare systems alike.

What Are Expandable Sheaths in Minimally Invasive Medicine?

Expandable sheaths are introducers that can widen inside the vessel after insertion. This flexibility allows larger devices to be inserted without causing trauma to the artery. Their main advantage is reducing vascular complications such as bleeding, dissection, and stenosis, while maintaining procedural efficiency.

FDA-Approved Expandable Sheaths for Minimally Invasive Procedures

Several devices are already FDA-approved and in wide clinical use:

• Medtronic Solopath™ Balloon-Expandable Sheath – FDA-cleared in 2018 for TAVR. Trial data showed a 52% reduction in vascular complications compared to standard sheaths.

• Edwards Lifesciences eSheath® – FDA-approved for Sapien 3/Ultra valves. The PARTNER 3 trial showed a 40% reduction in major vascular complications.

• Gore DrySeal Flex Introducer Sheath – FDA-approved for TEVAR/EVAR. Registry studies reported a 35% lower rate of access-site hematomas.

Clinical Impact of Expandable Sheaths

Expandable sheaths improve outcomes across multiple procedures:

• TAVR – Vascular complications reduced from 10–15% to 5–7%, with shorter ICU stays.

• TEVAR/EVAR – Access-site injury reduced from 8–12% to 4–6%.

• Lead extraction – Vascular trauma cut in half, lowering procedural mortality.

Fewer complications mean fewer transfusions, faster recovery, and shorter hospitalizations.

Future Applications of Expandable Sheaths

The potential of expandable sheaths extends beyond current uses:

• TMVR (Transcatheter Mitral Valve Replacement): Could cut iliac artery injuries by half.

• Peripheral artery interventions: Projected to lower complication rates from up to 18% to around 8%.

• Pediatric procedures: Smaller expandable sheaths may reduce femoral artery stenosis to 2–4%.

• Neurovascular interventions: Controlled expansion could lower embolism risk to 2–3%.

• High-risk PCI: Safer delivery of mechanical support devices with fewer vascular injuries.

Benefits for Patients, Surgeons, and Healthcare Systems

• Patients – Faster recovery, fewer complications, shorter hospital stays.

• Surgeons – Easier procedures, less risk of vascular injury, reduced operating time.

• Healthcare systems and insurers – Lower readmission rates and cost savings of $3,000–5,000 per case.

Challenges and Barriers to Adoption

Despite clear benefits, adoption of expandable sheaths faces:

• Higher upfront cost (20–30% more than standard sheaths)

• Need for surgeon training in expansion techniques

• Limited compatibility with all devices

Ongoing innovation and cost reduction are expected to broaden adoption.

Conclusion

Expandable sheaths in minimally invasive medicine are a game-changer. FDA-approved devices already show dramatic reductions in vascular complications, and expanding their use could prevent thousands of complications annually. Patients recover faster, surgeons gain procedural confidence, and healthcare systems save costs—highlighting the transformative potential of this technology.

Mechanical properties of vascular grafts play a critical role in medical procedures, serving as substitutes for damaged or diseased blood vessels. Ensuring the right mechanical characteristics is essential for long-term graft functionality and patient safety. This article explores the key mechanical properties required for vascular grafts, the challenges in balancing them, and the latest innovations in materials and manufacturing techniques.

Key Mechanical Properties of Vascular Grafts

Understanding the mechanical properties of vascular grafts is crucial for designing effective implants. The most important properties include:

• Compliance: The ability of a graft to expand and contract with pulsatile blood flow. Mismatched compliance can lead to complications such as intimal hyperplasia.

• Tensile Strength: Measures resistance to longitudinal and circumferential stress, preventing structural failure.

• Burst Pressure: Defines the maximum pressure a graft can endure before rupture, ensuring durability under physiological conditions.

• Suture Retention Strength: Evaluates the graft’s ability to hold sutures without tearing, which is critical during surgical implantation.

• Elastic Recovery: The capacity to return to its original shape after deformation, ensuring consistent performance.

• Stiffness: Resistance to deformation under force, which should ideally align with the mechanical properties of native vessels.

• Wall Thickness: Influences strength, compliance, and the ability to mimic natural vessels.

• Dynamic Compliance: Expansion and contraction under pulsatile flow, crucial for maintaining proper circulation.

• Internal Diameter: Must match the native vessel to prevent flow disturbances and thrombosis.

• Viscoelasticity: A time-dependent response to stress, mimicking natural vessel behavior.

Challenges in Balancing Mechanical Properties

Designing vascular grafts requires careful trade-offs:

• Compliance vs. Strength: High compliance increases flexibility but may reduce tensile strength and burst pressure.

• Wall Thickness vs. Compliance: Thicker walls enhance strength and suture retention but can reduce natural vessel mimicry.

• Stiffness vs. Compliance: While structural integrity is critical, excessive stiffness may lead to graft-vessel mismatch.

• Elastic Recovery vs. Viscoelasticity: Balancing immediate shape recovery with natural time-dependent behavior is challenging.

• Internal Diameter vs. Wall Thickness: Small-diameter grafts make this balance particularly difficult.

• Material Limitations: No single material meets all mechanical requirements, often necessitating composites.

• Long-Term Stability vs. Initial Properties: Maintaining performance over time without degradation is a key concern.

Recent Advancements in Vascular Grafts

Recent developments aim to optimize the mechanical properties of vascular grafts:

Synthetic Materials

• Expanded PTFE (ePTFE): Offers high tensile strength and burst pressure, ideal for large-diameter grafts.

• Thermoplastic Polyurethane (TPU): Provides flexibility and durability, optimizing tensile strength, compliance, and burst pressure.

• Polyethylene Terephthalate (PET) Fabric: Balances durability, tensile strength, and compliance.

Composite and Hybrid Materials

• Layered and Hybrid Grafts: Combining synthetic and natural materials improves mechanical performance and biocompatibility.

• Electrospinning: Advanced technique for creating nanofibrous scaffolds with precise mechanical properties. Used with polyurethanes and biodegradable polymers like PCL, it allows customization of graft mechanics.

Conclusion

The mechanical properties of vascular grafts are fundamental to their effectiveness and longevity. Achieving the ideal balance between compliance, tensile strength, and durability remains challenging. Nevertheless, innovations such as composite grafts and electrospinning are driving next-generation solutions.

As technology advances, we move closer to creating vascular grafts that fully replicate native vessel behavior, ultimately improving outcomes in cardiovascular procedures.

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Technological advancements in peripheral vascular stents are revolutionizing the management of Peripheral Arterial Disease (PAD), providing safer, more effective solutions for patients. Among the primary options are bare metal stents (BMS) and covered stents, each offering distinct benefits and limitations. This article offers a detailed comparison of these devices, covering design, clinical applications, advantages, limitations, and evidence-based outcomes, while exploring the future of stent technologies in vascular treatment.

What Are Peripheral Vascular Stents? Types & Applications

Peripheral vascular stents are self-expanding devices designed to keep blood vessels open and prevent restenosis.
They are commonly used in:

• Peripheral Arterial Disease (PAD): Treating atherosclerotic blockages in iliac, femoral, or popliteal arteries.

• Aneurysms: Providing structural support to weakened vessel walls.

• Vessel Occlusions: Managing blockages in smaller peripheral arteries.

Types of Peripheral Vascular Stents

1. Bare Metal Stents (BMS): Made from nitinol or stainless steel, relying on natural endothelialization for vessel healing.

2. Covered Stents: Combine a metallic framework with a polymeric or fabric coating (e.g., ePTFE, Dacron) to improve sealing and reduce complications.

3. Hybrid Stents: Merge the features of BMS and covered stents, offering specialized solutions for complex lesions.

For more detailed information, check our guide on ePTFE-coated stents.

Covered vs. Bare Metal Stents: A Comparative Review

Bare Metal Stents (BMS)

BMS are commonly used for short lesions in large arteries, valued for their simplicity and flexibility.

Advantages:

• Superior trackability in tortuous anatomy

• Cost-effective compared to covered stents

• Smaller delivery systems for challenging anatomies

Limitations:

• Higher restenosis rates (20–40%) due to intimal hyperplasia

• Lack of sealing properties, unsuitable for aneurysms or vessel perforations

Covered Stents

Covered stents combine a metallic scaffold with a coating for enhanced sealing and protective functions.

Advantages:

• Improved occlusion rates for complex lesions

• Sealing capacity for aneurysms and perforations

• Lower risk of thrombosis compared to BMS

Limitations:

• Reduced flexibility, challenging deployment in tortuous vessels

• Higher cost

• Requires larger sheath sizes

Key Benefits with Advanced Coatings:

• Faster endothelialization and healing

• Improved biocompatibility, reducing inflammation

• Increased complete occlusion rates in long lesions and aneurysms

• Lower perioperative risks, such as thrombosis and infection

Challenges and Considerations

Despite their advantages, covered stents face some challenges:

• Material biocompatibility concerns may lead to inflammation or tissue growth

• Reduced flexibility may limit use in tortuous or calcified vessels

• Long-term durability and material degradation

• Regulatory approval requires extensive clinical testing

The Future of Peripheral Vascular Stents

Covered and hybrid stents are shaping the future of PAD treatment. With advances in material science, drug-eluting coatings, and bioactive surfaces, these stents are expected to overcome current limitations and enhance patient outcomes. They will likely become central to the management of complex vascular conditions.

Explore our peripheral vascular stent portfolio to learn more about our products and innovative coatings.

Selecting the right material for Dacron vs ePTFE vascular covers is essential for clinical success. Both materials offer unique properties for stents, grafts, and structural heart devices. This article highlights their advantages, disadvantages, and ideal applications to help guide material selection.

Advantages and Disadvantages of Dacron Vascular Covers

Advantages:

• Strong Mechanical Properties: Provides reliable structural support.

• Porous Structure: Facilitates tissue ingrowth and reduces device migration.

• Suitable for Larger Vessels: Ideal for vessels >10mm and structural heart devices.

• Ease of Suturing: Simplifies surgical procedures.

Disadvantages:

• Initial Inflammation: The woven structure can trigger early inflammatory response.

• Potential Complications: May cause thrombosis, intimal hyperplasia, calcification, and chronic inflammation.

• Suturing Requirements: Time-consuming and may increase cover thickness.

Advantages and Disadvantages of ePTFE Vascular Covers

Advantages:

• Excellent Biocompatibility: Highly compatible with body tissues.

• Lower Thrombogenicity: Reduced risk of thrombosis compared to Dacron.

• Porous Structure & Controlled Porosity: Promotes tissue integration.

• Suitable for Smaller Vessels: Performs well in vessels <6mm.

Disadvantages:

• Difficulty Suturing: More challenging to stitch than Dacron.

• Potential Complications: Can still lead to intimal hyperplasia and calcification.

• Higher Cost: Generally more expensive than Dacron.

Applications of Dacron

• Large-Diameter Vascular Grafts (>10mm): High patency rates (>85% at 5 years) and structural support.

• Structural Heart Devices: Heart valve sewing rings, annuloplasty rings.

• Hernia Repair Meshes: Durable support for abdominal wall defects.

• Ligament and Tendon Reconstruction: Used as artificial ligaments or reinforcement.

• Sutures: Non-absorbable sutures for long-term wound closure.

• Fabric-Covered Stents: Provides durable coverage promoting tissue integration.

Applications of ePTFE

• Small-Diameter Vascular Grafts (<6mm): Reduced thrombogenicity and optimized tissue integration.

• Hemodialysis Access Grafts: Lower infection rates and easy needle puncture.

• Aortic Replacement: Withstands high pressure and flow, customizable for flexibility.

• Cardiovascular Patches: Used in congenital heart defect repairs and vessel reconstructions.

• Endovascular Stent Grafts: Low profile, conforms to vessel walls, reduces endoleaks.

• Soft Tissue Augmentation: Plastic surgery for facial reconstruction and body contouring.

• Patches for Vessel Repair: Smaller vessels benefit from lower thrombogenicity and better handling.

Combined Applications

• Hybrid Vascular Grafts: Combines Dacron and ePTFE for complex reconstructions.

• Composite Hernia Meshes: Leverages both materials for strength and tissue integration.

Conclusion: Choosing the Right Material

The choice between Dacron and ePTFE depends on clinical requirements:

• Dacron: Best for larger vessels and high-stress areas due to strength and ease of suturing.

• ePTFE: Ideal for smaller vessels where biocompatibility and reduced thrombogenicity are essential.

Ongoing research continues to refine both materials, enhancing their performance and expanding their medical applications.

Precision in Modern Medical Devices

In today’s world of advanced medical technologies, precision is crucial, especially in developing minimally invasive devices. The growing demand for microlayer tubes made from low durometer materials is driving significant advancements in the field. While extruded tubes have traditionally been used for applications requiring stiffness and thick walls, they face challenges when applied to miniature devices with ultra-thin walls—such as those measuring 0.001″. This is where microlayer tubes make a difference.

The Advantages of Medibrane’s Microlayer Technology

At Medibrane, we offer a diverse selection of microlayer tubes designed to meet the most stringent requirements. These tubes feature a minimum wall thickness of just 0.00059″ and diameters ranging from 0.00394″ to 0.984″. Moreover, our proprietary polymer deposition methods enable us to create layers as thin as 0.0001″, achieving tolerances as precise as +/- 0.0002″.

Unparalleled Control and Flexibility

One of the standout benefits of microlayer tubes is their ability to provide superior control over wall thickness. As a result, inner lumen space is maximized, while the overall device profile remains minimal. Additionally, these tubes feature variable durometers along their length, enhancing flexibility and adaptability for diverse applications.

Meeting Manufacturing Challenges

Historically, producing large bore polymer tubing with ultra-thin walls posed significant challenges. However, Medibrane’s microlayer technology overcomes these obstacles. By leveraging innovative techniques, we can manufacture tubing that meets the needs of even the most demanding applications.

Material Adaptability for Custom Solutions

Our microlayer technology supports various durometer polyurethane resins, ranging from 55 shore D to 40 shore A. This flexibility allows us to cater to specific project requirements, ensuring optimal performance every time.

Practical Benefits for Medical Applications

In addition to their precision, microlayer tubes offer other key advantages. For instance, they significantly reduce the tackiness of soft materials. This characteristic is critical in applications requiring smooth and non-sticky surfaces, such as neurovascular microcatheters and large-diameter delivery systems for structural heart devices.

Transforming the Medical Industry

As the demand for precision in minimally invasive devices continues to grow, microlayer tubes are poised to revolutionize the industry. Their exceptional control over wall thickness and ability to adapt to various durometers make them invaluable for developing advanced medical technologies.

Learn more about our advanced polymer solutions, or explore our custom coating processes that complement microlayer tubing.
For a quick purchase of our microlayer tubes, visit us on Chamfr.