Hemostasis Blog Valued Resource!

The Medical Hemostat Blog has gained wide geographical and company interest. You are welcome to contact me at hemostatguy@gmail.com. I also have consulted with market research firms such as Frost and Sullivan amongst other research organisations.

While I address a need for comprehensive information regarding hemostasis, I am pleased to announce our top, google analytics identified company visitors:

1. Johnson & Johnson
2. CryoLife
3. Baxter
4. Trauma Cure
5. Tyco
6. Zymogenetics
7. Medafor
8. Hemcon
9. King Pharmaceuticals
10. Entegrion
11. St. Jude
12. Aventis Behring

I would appreciate any contributions readers care to send and am actively seeking projects in this field.

Thank You for following the Blog.

HG

Gore Reports First Patient Case Using GORE® DrySeal Sheath

GORE® DrySeal Sheath. The sheath aids in minimally invasive treatment for patients with abdominal aortic aneurysms (AAA) with the GORE® EXCLUDER® AAA Endoprosthesis and thoracic aortic aneurysms (TAA) with the GORE® TAG® Thoracic Endoprosthesis. The successful procedure was performed by Alan Lumsden, M.D., chairman of the Department of Cardiovascular Surgery, The Methodist Hospital (TMH) in Houston, TX, during a Gore-sponsored Acute Symptomatic AAA Workshop conducted in The Methodist DeBakey Heart and Vascular Center.

Gore received FDA clearance in April 2010 to market the GORE DrySeal Sheath, which is comprised of the innovative hemostatic GORE DrySeal Valve attached to the introducer sheath. The GORE DrySeal Valve is truly unique in that it is pressurized to create a seal, thereby minimizing blood loss and accommodating multiple wires and catheters simultaneously. The valve consists of a silicone outer tube and an inner film tube that create an effective hemostatic seal that easily adapts to the profiles of the inserted devices. The device is available in profiles from 12 to 26 Fr, in 2 Fr increments, and has a working length of 28 cm.

According to Dr. Lumsden, “The ability of the GORE DrySeal Valve to accommodate multiple devices during difficult procedures with minimal blood loss keeps the operating field free from excess blood, while helping to prevent unnecessary blood loss to the patient. The GORE DrySeal Sheath requires no intra-procedural manipulation of the valve, delivering consistent performance throughout the procedure and allowing the physician to maintain focus on the endovascular procedure – without being concerned about blood loss at the patient access site.”

Gore Aortic Business Leader David Abeyta added, “This latest addition to Gore’s portfolio of world-class endovascular devices and accessory products minimizes patient blood loss during procedures with endovascular devices, such as the GORE EXCLUDER AAA Endoprosthesis.”

FDA Issues St. Jude Warning Letter Over Epicor Surgical Ablation Device

A Warning Letter from the U.S. Food & Drug Administration (FDA) to St. Jude Medical Inc. has been posted on the agency’s web site. The letter alleges that St. Jude promoted the Epicor surgical ablation device to treat atrial fibrillation, a use that has not been approved by the agency.

Surgical ablation devices like the Epicor system are approved for “ablation,” or the burning of tissue, to seal a wound to stop bleeding. While doctors are permitted to use medical devices in any way they see fit, manufacturers are legally barred from marketing or promoting such uses. St. Jude has received the go-ahead from the FDA to investigate the Epicor system’s use in treating atrial fibrillation, but not approval to market it for this use.

In a Warning Letter dated April 23, the FDA cited marketing statements such as one on the St. Jude’s website last year that the Epicor system is “designed to safely, effectively and reproducibly create a classic box lesion in a single step.” According to The Wall Street Journal, the statement referred to a pattern of burns imprinted on the heart during atrial fibrillation surgery. The letter said statements like that violated the Federal Food, Drug and Cosmetic Act.

The letter also said the FDA found similar problems with marketing brochures and materials aimed at physicians.

Recently, St. Jude acknowledged an investigation by the U.S. Department of Justice into similar false marketing claims involving Epicor. In its most recent quarterly report, the firm stated that it had received a letter from the Department in October 2008.

In March, we reported that Medtronic Inc. and Boston Scientific Inc. had confirmed that the Department of Justice was investigating their marketing of the devices. Another firm, AtriCure, agreed to pay $3.8 million to resolve allegations it marketed its surgical ablation devices for the unapproved purpose of treating atrial fibrillation.

It is estimated the about 80 percent of atrial fibrillation patients are effectively treated with drugs. Unfortunately, there are few studies available that compare the safety of ablation to other types of atrial fibrillation treatments. Since 2008, there have been at least five U.S. patient deaths reported to an FDA data base in procedures using AtriCure devices and one involving a Medtronic device.

New Surgical Device Makes Cleaner Incisions

The scalpel could soon be a thing of the past...A high-tech way to cut through skin and tissue creates less heat damage than standard methods.Wendy Rigby has the story.Deborah Hackworth is about to go under the knife at nix hospital in San Antonio.Her surgeon will be using a new tool to cut out a suspicious lump in her left breast.Hackworth says, "I think patients will recover quicker. I think there will be less pain involved for us."The tool, called the plasma blade, is a new kind of cutting device.Plasma is the same energy used in neon signs and some flat screen TV's.Here in the o-r, the energy is used to cut through skin and tissue, generating less heat than conventional techniques.Breast surgeon Dr. Kathryn Wagner has embraced this new technology.Dr. Kathryn Wagner says, "This is a revolutionary new tool and a way to perform surgery. It replaces both the scalpel and electrocautery, traditional electrosurgery. When you use this device to cut the skin, you get a clean cut with no burn just like a scalpel. Except there's no bleeding."Wagner has been using the plasma blade for about a year now.She says she's impressed with the lack of heat damage it leaves behind.And she's noticed less pain for her patients, a decrease in scarring and faster healing after surgery.Dr. Wagner says, "I think this is the best thing since electrocautery was invented. Aesthetics and pain, a lack of pain from surgery. The difference is pretty impressive."Now, Wagner uses the plasma blade on almost every case.

Excessive use of toxic materials in medical nanotechnology could be avoided

(Nanowerk Spotlight) Metal nanomaterials are often synthesized using the toxic reagent formaldehydeat concentrations thousands of times higher than necessary. Many of these same nanomaterials are being investigated for use in cancer treatment – however, there is a risk that they could do more harm than good. The large excess of formaldehyde that is used originates from methods developed 100 years ago. Because these methods work well, they have stood the test of time. By better understanding the role that formaldehyde plays in nanomaterial synthesis it will become possible to reduce or eliminate this toxic reagent. By eliminating formaldehyde it will become safer to prepare these nanomaterials and safer to use them in cancer treatment.

"The observation that previous synthetic routes for nanoshell and core-shell nanoparticles utilize a large excess of formaldehyde suggested an opportunity for minimizing the quantity of formaldehyde used,"Scott Reed, an assistant professor of chemistry at the University of Colorado at Denver, tells Nanowerk. "However, the synthesis of gold-core, silver-shell nanoparticles that are active in the near-infrared requires the polymer that forms by reaction of formaldehyde and ammonium hydroxide. Until a replacement polymer is found, formaldehyde is required to obtain the desired optical properties."

In a recent paper in the May 19, 2010 online edition of Chemistry of Materials ("Minimizing Formaldehyde Use in the Synthesis of Gold-Silver Core-Shell Nanoparticles"), Reed's team and colleagues from Portland State University describe an effort to minimize the amount of formaldehyde used for coating silver onto gold nanoparticles. They describe a strategy where formaldehyde use can be reduced 100-fold from prior routes and this minimization strategy can be applied to other nanoparticle syntheses.

"We discovered that most of the formaldehyde used in preparing silver nanomaterials is consumed by formation of a polymer" Reed explains. "Formaldehyde reacts with ammonium hydroxide to form a previously unnoticed polymer. When we decreased the ammonium hydroxide concentration it became possible to decrease the formaldehyde concentration, too."

At the same time, these materials maintain optical activity in the near-infrared, the property that makes them attractive for treating cancer with light.

The excessive use of toxic formaldehyde in fabrication processes for nanomaterials is particularly worrisome in the area of nanomedicine where these materials are deliberately injected into the body for diagnostic or therapeutic purposes. Many of the synthetic routes to nanoshells and core-shell metal nanoparticles use a large excess of the toxic reagent formaldehyde as a reducing agent.

Reed notes that one of the early methods reported for coating silver on silica spheres made use of 1 mmol of formaldehyde for reduction of a 0.15 mM solution of silver ("Silver Nanoshells: Variations in Morphologies and Optical Properties").

He estimates that a 3000-fold more formaldehyde is used to prepare silver nanoshells than necessary.

"This large excess is based on Zsigmondy's original silver nanoparticle synthesis reported in 1927 and is typical of coating procedures" he continues. "Other reports have used a 1000-fold excess for coating silver on polystyrene beads or gold nanoparticles, up to 320-fold excess for coating silver on silica nanowires, a 346-fold excess to coat silver onto latex spheres, and a 24000-fold excess for layering silver onto tin-coated silica nanoparticles."

Representative TEM image of core-shell nanoparticles prepared using a mixture of formaldehyde and ascorbic acid. One-half a microliter of formaldehyde was incubated with 4.5 mL water for 15 min prior to addition of 0.5 mL of gold nanoparticles and 0.2 mL of 1.1 mM silver nitrate followed by 21.2 µL ammonium hydroxide after a 5 min incubation and 0.1 mL of 0.534Mascorbic acid after an additional 5 min incubation. Scale bar=20 nm. (Reprinted with permission from American Chemical Society)

Demonstrating an approach to developing greener synthesis methods, Reed and his team fabricated silver-coated gold nanoparticles suitable for phototherapy. Although formaldehyde still is an essential component of this process, they were able to reduce its amount 100-fold compared to previous processes. Part of this minimization resulted from the discovery that ascorbic acid (vitamin C) can be used as a reducing agent in combination with formaldehyde.

"Understanding this previously overlooked polymer formation is a good starting point for minimizing formaldehyde use in the synthesis of nanoshells and other core-shell nanomaterials" says Reed. "We expect that this will result in greener syntheses and more biocompatible nanomaterials suitable for medical applications."

In previous Nanowerk Spotlights we have raised the issue that today's nanomanufacturing processes actually are quite dirty and polluting activities ("Not so 'green' nanotechnology manufacturing"). As Reed and his collaborators show, by designing greener synthetic routes it will become possible to more safely prepare metal nanoparticles without creating hazardous waste. An issue that is particularly important for applications in nonomedicine.

As this particular example shows, this new understanding of formaldehyde will allow for changes in how many types of nanomaterials are synthesized. Nanoparticles prepared using green methods are more likely make it through the regulatory hurdles associated with medical applications.