Conceptually, a stent’s design and architecture are based on the underlying rationale of providing adequate endoluminal scaffolding support of recanalized vascular conduit for a desired period of time, with minimally possible obstruction of normal circulatory flow and propensity to reocclusions associated with healing processes or other plausible causes. Stenting device designs also tend to reflect etiological and anatomical specifics of the targeted occlusive conditions and indications, characteristics of preferred device materials, and technical capabilities of existing manufacturing tools and technologies.
Common Peripheral Vascular Metal Stent Designs. The vast majority of peripheral vascular stents on the market (which are usually made of metal structural materials) typically feature one of three basic designs: slotted tube, wire mesh, or flattened coil/spiral. The same basic designs are used in non-vascular metallic stents, which in many instances constitute a line extension of corresponding vascular systems.
The most popular slotted tube stents – which are cut from tubular metal structures with computer-guided laser and electropolished – are available in several design sub-types including closed-cell flexsegment, open-cell multilink and micromesh versions. Generally, all slotted tube stenting devices combine good radial strength, relatively even distribution of scaffolding support, and minimal foreshortening, and compatibility with low profile delivery systems. The closed-cell flexsegment architecture (usually featuring circumferentially distributed hexagonal, heart, or diamond-shaped cells with one or more common sides) offers enhanced scaffolding and relative lesion coverage at the expense of longitudinal flexibility and kink resistance. open-cell multilink design (with sinusoidal ring-segments and evenly spaced co-axial links/ connectors) provides significantly better longitudinal flexibility (particularly with the use of corrugated links) and more even endoluminal support which come at a price of reduced stent to lesion surface ratio and reduced radiopacity. The micromesh configuration (representing a high-density hybrid version of the close-cell flexsegment and open-cell multilink architectures, with larger number of smaller zigzag cells per ring and closely linked ring segments) approximates the advantageous features of the both designs by offering significant improvement in flexibility over the former one better stent-to-vessel/lesion ratio compared to the latter one.
The wire mesh – featuring unrestricted diamond-shaped cells formed by one or several diagonally interwoven (braided) wire filaments – is arguably the oldest type of metal stent design. High stent-to-vessel/lesion surface ratio, good conformability and even scaffolding, along with technological simplicity and relatively low manufacturing cost constitute the primary benefits of braided wire mesh stenting devices. Unfortunately, such devices are also characterized by a mediocre radial strength, very significant (up to 15%) foreshortening, and poor kink resistance, which radically undercut their utility in critical indications.
Coil or spiral stents (which could be configured as a single or double helix with a flat or flattened wire struts) theoretically offer the best combination of radial strength and longitudinal flexibility. However, spiral devices are also characterized by significant foreshortening, propensity to recoil, and uneven scaffolding support in bended or bending circulatory conduits.
Comparative Advantages and Drawbacks of Most Common Stenting Device Designs
See “Global Market Opportunities in Peripheral Arterial and Venous Stents, Forecast to 2020”, Report #V201. Details.
Critical limb ischemia, aortic aneurysm, chronic venous insufficiency and other pathologies continue to represent vertical and horizontal opportunities for medtech manufacturers, with expanded clinical applications and global growth, according to MedMarket Diligence.
“Peripheral arterial and venous vessel pathologies reduce the quality of life and can be fatal, but medtech manufacturers have developed highly effective peripheral stents, using core platform technologies often developed in parallel with those for coronary applications,” says Patrick Driscoll of MedMarket Diligence. These pathologies include the most prevalent occlusive circulatory conditions affecting the abdominal and thoracic trees (including aortic aneurysm) and lower extremities as well as the venous outflow conditions, deep venous thrombosis and chronic venous insufficiency.
“By 2020, these pathologies will produce over 2 million interventions annually worldwide, arising from opportunities for improved performance in challenging vasculature as well as from the growing economies, especially China, in the Asia-Pacific region,” says Driscoll, who notes that venous stenting’s very large potential patient caseload opportunity is of particular interest to a number of key medtech players who have already taken steps toward seizing it.
Peripheral stenting systems are used for the management of occlusive disorders and other pathologies affecting peripheral arterial and venous vasculature. These include lower extremity bare metal and drug-eluting stents for treatment of symptomatic peripheral artery disease and critical limb ischemia resulting from iliac, femoropopliteal and infrapopliteal occlusive disease; stent-grafting devices used in endovascular repair of abdominal and thoracic aortic aneurysms; as well as a subset of indication-specific and multipurpose peripheral stents used in recanalization of iliofemoral and iliocaval occlusions resulting in CVI.
Stents, still a common clinical option in coronary ischemia, have migrated peripherally anatomically and far eastward geographically. Their use in peripheral applications is gaining speed, particularly outside western markets.
U.S. and Western European markets have longer history in the use of stents in peripheral arterial and venous stents, but Japan, India, and China have proven their capacity for demand in medtech.
Peripheral stents in global markets are the subject of the MedMarket Diligence, LLC, report (#V201), “Global Market Opportunities in Peripheral Arterial and Venous Stents, Forecast to 2020”.
The scope of market analysis of the MedMarket Diligence report #V201 is the universe of stenting systems intended for the management of occlusive disorders and other pathologies affecting peripheral arterial and venous vasculature. The cited systems include lower extremity bare metal and drug-eluting stents for treatment of symptomatic PAD and critical limb ischemia resulting from iliac, femoropopliteal and infrapopliteal occlusive disease; stent-grafting devices used in endovascular repair of abdominal and thoracic aortic aneurysms; as well as a subset of indication-specific and multipurpose peripheral stents used in recanalization of iliofemoral and iliocaval occlusions resulting in CVI.
From, “Global Market For Medical Device Technologies in Spine Surgery, 2014-2021”, Report #M540.
Spine surgery remains a uniquely American pastime, based at least on sales of technologies including spinal fusion, minimally invasive spine surgical technologies, and orthobiologics used for spine.
The patient demand and associated utilization rates, prices, reimbursement and other drivers make the U.S. an even bigger than it is in most medtech markets. And globally, as well as in the U.S., thoracolumbar fusion drives the most sales.
From, “Global Market For Medical Device Technologies in Spine Surgery, 2014-2021”, Report #M540.
The content of this post is drawn from the complete Report #S251, “Worldwide Wound Management, Forecast to 2024: Established and Emerging Products, Technologies and Markets in the Americas, Europe, Asia/Pacific and Rest of World”. For separate coverage of sealants, glues, and hemostats in wound management, see Report #S290.
The World Market for Wound Management Report encompasses twelve product segments:
Traditional Adhesive Dressings
Traditional Gauze Dressings
Traditional Non-Adherent Dressings
Negative Pressure Wound Therapy Devices
Bioengineered Skin & Skin Substitutes
Wound Care Growth Factors
The report examines North and South America, the European Union, Asia/Pacific and Rest of World, and looks at markets and growth rates by product and country for the years 2014-2024. The world market in 2024 for the total wound management market represented by the segments listed above is projected to be worth over $22 billion, with segments growing at widely variable rates, with lowest sales growth in traditional adhesive bandages and the highest sales growth in bioengineered skin and skin substitutes
Below are representative examples of each type of wound management product.
Hydrofilm, Release, Tegaderm, Bioclusive
Comes as adhesive, thin transparent polyurethane film, and as a dressing with a low adherent pad attached to the film.
Clean, dry wounds, minimal exudate; also used to cover and secure underlying absorptive dressing, and on hard-to-bandage locations, such as heel.
PermaFoam PolyMem Biatain
Polyurethane foam dressing available in sheets or in cavity filling shapes. Some foam dressing have a semipermeable, waterproof layer as the outer layer of the dressing
Facilitates a moist wound environment for healing. Used to clean granulating wounds which have minimal exudate.
Hydrosorb Gel Sheet, Purilon, Aquasorb, DuoDerm, Intrasite Gel, Granugel
Colloids which consist of polymers that expand in water. Available in gels, sheets, hydrogel-impregnated dressings.
Provides moist wound environment for cell migration, reduces pain, helps to rehydrate eschar. Used on dry, sloughy or necrotic wounds.
CombiDERM, Hydrocoll, Comfeel, DuoDerm CGF Extra Thin, Granuflex, Tegasorb, Nu-Derm
Made of hydroactive or hydrophilic particles attached to a hydrophobic polymer. The hydrophilic particles absorb moisture from the wound, convert it to a gel at the interface with the wound. Conforms to wound surface; waterproof and bacteria proof.
Gel formation at wound interface provides moist wound environment. Dry necrotic wounds, or for wounds with minimal exudate. Also used for granulating wounds.
A natural polysaccharide derived from seaweed; available in a range of sizes, as well as in ribbons and ropes.
Because highly absorbent, used for wounds with copious exudate. Can be used in rope form for packing exudative wound cavities or sinus tracts.
Biatain Ag Atrauman Ag MediHoney
Both silver and honey are used as antimicrobial elements in dressings.
Silver: Requires wound to be moderately exudative to activate the silver, in order to be effective
SNa V.A.C. Ulta PICO Renasys (not in USA) Prospera PRO series Invia Liberty
Computerized vacuum device applies continuous or intermittent negative or sub-atmospheric pressure to the wound surface. NPWT accelerates wound healing, reduces time to wound closure. Comes in both stationary and portable versions.
May be used for traumatic acute wound, open amputations, open abdomen, etc. Seems to increase burn wound perfusion. Also used in management of DFUs. Contraindicated for arterial insufficiency ulcers. Not to be used if necrotic tissue is present in over 30% of the wound.
There are some market restraints at work, primarily the high cost of the new technologies. Not all country healthcare budgets can afford advanced wound care products, even if they are proven to decrease healing times and hospital costs over the longer run. The development of substitute products threatens existing product categories, while a lack of sufficient clinical and economic evidence backing new technology hinders growth and acceptance of some of the more advanced wound management technologies.
In addition, improved wound prevention and a lack of regulation on tissue engineering in the EU are also expected to hold back the development of new technologies. In addition to market restraints, there are a number of drivers that are expected to shape this market in the years to come. One of the primary drivers is the aging of the global population. Chronic diseases, such as circulatory conditions, anemias and autoimmune diseases influence the healing process as a result of their influence on a number of bodily functions. Illnesses that cause the most significant problems include diabetes, chronic obstructive pulmonary disease (COPD), arteriosclerosis, peripheral vascular disease (PVD), heart disease, and any conditions leading to hypotension, hypovolemia, edema, and anemia. While chronic diseases are more frequent in the elderly, wound healing will be delayed in any patient with underlying illness. Happily, most wounds heal without any problems. However, chronic wounds may take months or years to fully close, or may never close. Chronic wounds adversely affect the individual’s quality of life, and are a leading cause of burgeoning healthcare costs. Type 2 diabetes represents 85-95% of all diabetes in developed countries, and accounts for an even higher percentage in developing countries. There were 26 million diabetic patients in the US in 2012 and 285 million patients globally. Of these patients, approximately 15% will develop a diabetic foot ulcer and 50% of these will become infected, representing an estimated 2 million patients. Diabetic foot infections are currently treated with systemic antibiotics, but the estimated failure rate of antibiotics for diabetic foot ulcers is in excess of 22%. A patient with diabetes is at significant risk of damage to tissues caused by impaired homeostasis due to the disease process. For example there is a tendency for such tissues to develop blockages in smaller blood vessels, which reduces the ability of these vessels to provide sufficient oxygen to tissues already under stress due to compromised nutrient supply and the diabetic condition. These patients then develop arterial ulcers. They may also have a tendency to suffer from venous ulcers, due to the underlying poor condition of cells as a result of the diabetes. The diabetic foot is the most common cause of non-traumatic lower extremity amputations in the US and Europe: there is an average of 82,000 amputations per year in the U.S., costing an estimated $1.6 billion annually. The estimated cost of foot ulcer care in the U.S. ranges from $4,595 per ulcer episode to more than $28,000 and the total annual cost of foot ulcer care in the US has been estimated to be as high as $5 billion.
Pressure, or decubitus, ulcers are another of the most common types of chronic wounds. The treatment of pressure ulcers places a major burden on healthcare systems worldwide, with an emerging additional cost of litigation increasing in importance over recent years. Healthcare practitioners need to be aware of both the direct and indirect costs and consider how the implementation of prevention protocols may offer cost savings in the longer term. The cost of a dressing for example as a prevention tool is minimal in comparison to the costs of treating an established pressure ulcer. Following are a few hard numbers on the true financial cost of pressure ulceration:
The estimated cost to the US hospital sector is $11 billion per annum
The estimated cost to the UK national health service is estimated at £1.4-£2.1 billion annually (4% of total NHS expenditure)
Lawsuits remain common in both acute and long term care — with high payments in certain cases
The average cost to treat an individual with an unstageable ulcer or a deep tissue injury is estimated to be $43,180
The average length of stay in hospital is almost three times longer for chronic wounds
The mean hospital cost for management of pressure ulcers in the U.S. is $14,426. In comparison, the same cost in Korea is identified as $3,000-$7,000.
The cost of treating chronic wounds is one element driving the development and utilization of advanced wound care technologies. Other drivers are the aging of the population, and the obesity epidemic, which is expected to produce a wave of diabetics in the years to come.
Whether sales growth arises by a preferred adoption of one technology over another or by better than average economic conditions — or both, sales of wound management products are driven by technology adoption rates that vary by country, clinical practice patterns, reimbursement and other variables.
We assessed current and forecast sales for the following products:
Traditional Adhesive Dressings
Negative Pressure Wound Therapy
Bioengineered Skin & Skin Substitutes
For all product segments but the traditional adhesive, gauze, and non-adherent wound care products (which were assessed only at the global level), we assessed growth in each of the following countries/regions: Americas (USA, Rest of North America, Latin America), Europe (United Kingdom, Germany, Italy, France, Spain, Rest of Europe), Asia/Pacific (Japan, Korea, Rest of Asia/Pacific), and Rest of World.
From our examination (report #S251) of the global market for wound management products, below are the top product-country cohorts in terms of projected compounded sales growth from 2015 to 2024.
Bioengineered skin, skin substitutes, foam dressings, hydrocolloids, and growth factors are among top growth segments in a global market for advanced wound management that is otherwise modest in growth, but high in volume.
The 2016 global wound management market will hit nearly $15 billion. With sales growing at just better than 5% annually on population growth, migration of technologies to developing markets, and increased per capita utilization, the aggregate market is stably tied to persistent caseload. This regular, high volume of wound product sales supports a steady stream of innovation intended to gain even the smallest edge in share, an advantage that gains its value in real terms from the multiple of such a large global caseload.
In a market in which autografts and allografts have long been common, the development of cost-effective and safe bioengineered skin and skin substitutes is finding ready adoption in wounds of all types, but particularly burn wounds.
Due to their small base of existing sales thus far, even incremental expansion of sales in the use of biological growth factors in wound management reflects high growth through the forecast period.
Biotech need not be behind the higher growth in wound management technologies. Excellent growth prospects are also seen in foams, hydrogels, hydrocolloids, and other dressing materials.
Physical systems, including negative pressure wound devices, are not demonstrating growth prospects as good as traditional wound dressing products, let alone advanced wound products.
In short, the large global market is stable and growing at best modestly, but within this market, advanced wound management technologies’ sales are accelerating at the expense of traditional wound products. Growth in wound management is clearly coming from within.