News From the 2012 Meeting Society of International Radiology

Dr. Mark Garcia Provided Data Showing Minimally Invasive Treatments Can Restore Blood Flow and Improve Quality of Life for Patients Suffering from Post-Thrombotic Syndrome

Mark J. Garcia, M.D., FSIR , chief of vascular interventional radiology and medical director of heart and vascular peripheral labs at Christiana Care Health System in Newark, DE , reported to attendees at this year’s Society for Interventional Radiology that there are better treatments to restore blood flow, which can improve the quality of life for patients suffering from post thrombotic syndrome.

Garcia said that in the United States alone, blood clots affect up to 600,000 individuals annually. And despite providing appropriate medical therapies, as many as 50 percent of patients will go on to develop post-thrombotic syndrome, characterized by chronic, life-altering symptoms that include leg pain, swelling, fatigue and sometimes permanent skin changes including ulcers.

“The important message from our study is there is hope for those patients suffering from post-thrombotic syndrome who have been told there are no treatment options available.” Garcia noted that although great strides have been made in the treatment of acute clots, there have been no real improvements in treatment strategies for chronic clot and post-thrombotic syndrome. He said that medical management with blood thinners and elastic compression stockings are both aimed at the prevention of symptom progression rather than resolution. Garcia serves as chair of the Society of Interventional Radiology’s Venous Service Line.

Garcia says his team found encouraging technical and clinical outcomes when people were aggressively treated for chronic DVT causing post-thrombotic syndrome. “Contrary to popular belief, anticoagulants do not actively dissolve the clot; they just prevent new clots from forming. If people are treated with blood thinners alone, the clot remains in the leg. While the body can dissolve a clot over time, the vein often becomes permanently damaged during that time,” explained Garcia. “While post-thrombotic syndrome used to be considered an unusual, long-term aftereffect of deep vein thrombosis, it actually occurs frequently and can occur within two months of developing DVT ,” said Garcia. In his presentation, Garcia shared that there is increasing evidence that early and complete removal of the blood clot is likely to give people their best chance to avoid disabling symptoms, such as pain, swelling, skin changes and ulcer formation.

“Over a three-year period, we performed minimally invasive treatments to try and restore blood flow in more than 100 people suffering from lifestyle-limiting postthrombotic syndrome from chronic deep vein thrombosis,” explained Garcia. “We evaluated our ability to pass through the blocked area as well as our ability to restore blood flow using a combination of treatments. These included angioplasty, the insertion of a very small balloon through a small nick in the skin and threaded under X-ray guidance into a blood vessel and to the site of the blockage. The balloon is then inflated to open the vessel. We also looked at results of stenting - the insertion of a tiny mesh tube under X-ray guidance, to hold the vessel open, thrombolytic therapy - where drugs that dissolve clots are injected through a catheter to eliminate the clot and restore blood flow, and ultrasound accelerated thrombolysis,” he added.

Bariatric Arterial Embolization Can Allow for Precise Targeting to Decrease Hormone Production that Causes Hunger

According to the Centers for Disease Control and Prevention, approximately 127 million Americans are overweight, obese or morbidly obese. The rate of morbid obesity is also rising rapidly. Two new studies that explored the use of proven interventional radiology treatments in new ways, which may have the potential to help individuals with morbid obesity, were introduced at the Society for Interventional Radiology’s (SIR ) 37th Annual Scientific Meeting in San Francisco, CA .

Charles Y. Kim, M.D., assistant professor of radiology at Duke University Medical Center in Durham, NC , reported minimally invasive treatments that may target hunger at its source. Another uses X-ray visible embolic beads to block arteries to the stomach and suppress hunger, and a third explores the use of stem cells to repair vertebral disc degeneration. Initial results from all these studies were reported at the SIR meeting. Dr. Kim is the lead investigator on one of the studies.

“Currently, there are three clinically viable surgical alternatives for obesity: gastric bypass surgery, gastric
pacing and endoscopic gastric banding. These procedures have varying success rates; they are invasive, require extensive gastric/bowel reconstruction or external devices and can have significant surgical complications.” Kim said their promising results led them to believe that bariatric arterial embolization would allow for precise targeting of a specific portion of a person’s stomach in order to decrease production of ghrelin, a hormone that causes hunger. “This treatment could one day be the answer for those who have not been successful with weight loss through diet and exercise,” said Kim.

The interventional radiologist uses a thin catheter to inject tiny particles into an artery supplying the area being treated with the goal of blocking tiny vessels to starve it of its blood supply. “Interventional radiologists have safely and effectively used embolization in many other disease states for decades,” stated Kim. “For this study, we selectively blocked and decreased the blood flow to a very specific part of the stomach using specialized radiologic equipment, which led to significantly decreased levels of ghrelin in the animals that we treated.” Kim said they found that when ghrelin levels decrease, appetite and hunger also decrease, causing weight loss in the treated animals relative to nontreated animals. “Bariatric arterial embolization may have a future use in treating obesity in humans by significantly suppressing appetite to achieve weight loss,” Kim added.

The researchers will continue studies aimed at the reduction and elimination of complications, such as stomach ulcers, and expressed confidence that bariatric arterial embolization is very close to moving toward the clinical trial phase in the United States.

At the same time, a second study tested a new type of X-ray-visible embolic bead in bariatric arterial embolization. “Until now, clinically available embolic beads have not been visible on X-ray during or after delivery. We developed a new embolic bead that can be seen directly by X-ray imaging and have tested them in the new bariatric embolization treatment for obesity,” explained Clifford R. Weiss, M.D., assistant professor of radiology at Johns Hopkins University, School of Medicine in Baltimore, MD .

“The current system requires that the beads be mixed with X-ray-visible contrast agents before delivery. Although this mixture is visible during infusion, the contrast immediately washes away, and the location of the beads can no longer be ‘tracked,’” Weiss said. “By making the beads X-ray visible and using them in tandem with C-arm cone-beam CT , these beads can be tracked both during and after delivery. This allows for more precise assessment of ‘on-target’ embolization,” he said. “Due to the fact that these beads are visible and can be tracked over time, we should be able to assess their longterm presence. If needed, the patient can then be retreated. With the current clinically available beads, it is not possible to determine whether they are intact and functional over time. We recommend further studies to prove the beads’ safety over time and ensure they do not have any unintended effects on the target organs or on the individuals being treated,” he added. “We believe there are myriad possible applications for these beads, such as treating cancer of the liver or noncancerous uterine masses,” stated Weiss.

In a third study, a research team showed in animals that stem cells can be injected using only a needle, under X-ray guidance, into degenerated, painful intervertebral discs and initiate their repair.

“Even though 80 percent of people will have painful degenerated discs by age 65, and degenerated intervertebral discs are a significant contributor to low back pain, effective therapies are lacking. The current treatment is surgical removal of these damaged discs, which often requires more than one surgical procedure. Interventional radiologists acted on a need for a minimally invasive treatment that could mean faster recovery and less need for repeat surgeries in individuals suffering from debilitating disc disease,” explained J. David Prologo, M.D., an interventional radiologist at University Hospitals Case Medical Center in Cleveland, OH. “Stem cell therapies are increasingly showing great promise for disc regeneration and biological repair and may represent a promising alternative to destroying the disc, replacement or immobilization,” noted Prologo.

“All adults have stem cells that can be isolated from their bone marrow, and we observed that repair could be achieved by injecting a person’s own stem cells into the bad discs,” said Prologo. “After attaching an imaging agent to the injected cells, we were able to prove accurate delivery and containment of those cells at the desired site of action. We are now performing the first in human trials of this technique,” he added.

“The use of interventional radiology for the delivery of regenerative therapies, such as stem cells, can lead to other minimally invasive procedures associated with potential symptom relief and decreased cost and complications associated with open surgery,” Prologo stated. “This research may serve as a precedent for a wide variety of stem cell applications in humans through interventional radiology,” he said.