April 21 , 2008
Postcards From Washington, D.C. — SIR 2008
Vol. 9 No. 8 P. 20
Editor’s Note: This article is compiled from information provided by the Society of Interventional Radiology’s (SIR) media relations staff at the society’s 33rd Annual Scientific Meeting held March 15 to 20 in Washington, D.C.
DVT Registry Demonstrates Effectiveness of Intervention
Registry data for more than 500 patients presented at SIR’s annual scientific meeting show that deep vein thrombosis (DVT) treatment with the Trellis dispersion device breaks up blood clots in most patients more quickly than using drugs alone.
“It gets the clot out right away, restoring blood flow in the vein while the patient’s blood becomes sufficiently thinned by anticoagulation medication to prevent blood clots in the future,” said interventional radiologist Gerard J. O’Sullivan, MD. “Patients experience dramatic relief of pain, swelling, and skin discoloration in just a few hours.”
The Trellis device, developed by Bacchus Vascular of Santa Clara, Calif., combines the use of clot-busting drugs with a drug dispersion device to break up the clot faster. The Trellis is approved by the FDA as a drug-infusion catheter for peripheral vascular clots.
Because the device disperses the clot-dissolving drug throughout the clot, it allows the drug to work more quickly. Currently, most patients are put on blood thinning medication, which prevents future clots but does not break up the existing clot.
Using imaging for guidance, the Trellis-8 Infusion System is positioned at the clot site, and a balloon is inflated on both sides of the clot to prevent pieces of it from traveling to other parts of the body and to isolate the treatment zone so there is less chance the infused drug will cause bleeding. Then a dispersion wire is fed through the system’s catheter. The wire begins to rotate, mixing the clot-busting drug within the clot; the clot pieces are aspirated into the catheter and removed from the body.
The Trellis device removes the clot and restores blood flow more quickly than the current catheter-directed thrombolysis technique, which uses a drug alone and can take as long as two to three days to be effective. “My Trellis patients not only felt better right away, but they continued to feel good months later. With anticoagulation alone, it may take days to months for patients to feel better, and some never feel better,” said O’Sullivan.
Some larger clots do not break up on their own, leaving the patient with an underlying obstruction or lesion that should be corrected to prevent a future clot. Postthrombotic syndrome (PTS), while not life threatening, limits a person’s ability to walk or stand for a period of time and can be disabling.
DVT can lead to serious consequences, including pulmonary embolism (PE) or PTS, a condition characterized by chronic leg pain, swelling, and ulcers. The clot may eventually dissolve on its own, but in the meantime, the veins are permanently damaged. PTS is caused by a combination of vein valve damage and blocked blood flow from residual thrombus.
Approximately 200,000 people die annually from PE. The standard initial treatment with blood thinners is important to prevent a life-threatening PE but does not treat the existing clot. There is growing awareness in the medical community of the need to aggressively treat DVT.
“This is a very significant advance in DVT treatment, which hasn’t changed in more than 40 years,” noted O’Sullivan. “The procedure is now so commonplace where I work that the ER, oncology, and general medicine doctors all refer patients directly to me for this procedure because it works so well and is so safe. With the aid of the Trellis device, this interventional radiology procedure could really change the way DVT patients are treated and should become a standard of care.
“All acute DVT patients should be sent to the interventional radiology department for a consult,” he added. “We can help their physicians determine the best course of action. If the vein is completely or severely blocked, immediate treatment is needed. Not all partial clots will require treatment, but if the area is still swollen after five to seven days, patients should ask for an appointment with an interventional physician at the hospital.”
For the study, there were 565 limbs treated in 532 patients. The vein was reopened in all cases, and the treatment worked on acute or chronic clots. This is important because acute, fresh clots are more easily treated. Sixty-eight percent of the patients’ thrombi were in the iliac vein, 19% in the smaller femoropoliteal veins, and 13% in the subclavian vein.
Thrombus is generally classified by how long it has been present in the body. SIR’s reporting standards define acute as 14 days or less, subacute as 15 to 28 days, and chronic as more than 28 days. Thrombus was acute in 28% of limbs, acute on chronic in 44%, subacute in 11%, 12% subacute on chronic, and chronic in 6%, per the SIR clotage classification guidelines. Combined grades II and III lysis (greater than 50% to 100% thrombus removal) were established in 96.8% of acute onset of symptoms, 93.6% in acute on chronic, 96.7% in subacute, 89.2% in subacute on chronic, and 90.9% with chronic onset of symptoms, with venous patency achieved in all cases.
No adverse events were reported in the acute procedural follow-up period. Venous angioplasty and/or stenting were also used in the study in conjunction with the Trellis procedure to treat underlying problems in some patients, such as narrow areas in the vein that would make them susceptible to future clots.
Abstract 4, “An Endovascular Approach to Deep Venous Thrombosis Utilizing Isolated Thrombolysis and Adjunctive Measures,” is available online at www.SIRmeeting.org.
Localized Retinoblastoma Treatment May Save Eyes
A new interventional treatment successfully treats advanced retinoblastoma—a deadly, inherited, pediatric cancer of one or both eyes—and often spares children from having their eyes surgically removed, according to study results released at SIR’s annual scientific meeting. Advanced retinoblastoma is the most common eye cancer in children. Because there is no effective drug treatment, it is usually treated by removing the eye to prevent the cancer from spreading.
“This new interventional radiology treatment is a tremendous advance in treating retinoblastoma. It allows many children to keep their eyes and, in some cases, restores vision,” said Y. Pierre Gobin, MD, attending radiologist, professor of radiology and neurosurgery, and director of interventional neuroradiology at NewYork-Presbyterian Hospital/Weill Cornell Medical Center in New York City. “In this research study, we enrolled 21 patients with advanced retinoblastoma for whom conventional treatment is enucleation.”
During the new treatment, the physician delivers the drug directly to the eye via the ophthalmic artery, which allows a larger curative dose of the cancer drug Melphalan to be given than with intravenous chemotherapy. Using moving x-rays, an interventional radiologist threads a catheter up the femoral artery, guides it to the ophthalmic artery, and injects the drug. The retinoblastoma is very sensitive to Melphalan, and the eye tolerates the drug well while the rest of the body receives a nontoxic dose. Three intra-arterial chemotherapy treatments are usually sufficient; however, physicians have given up to six treatments. The tumor visibly shrinks within three weeks.
The treatment cured one half of the patients for whom there is enough follow-up data and improved vision in some. In some cases of retinal detachment, the interventional treatment also allowed for the recovery of some vision. Whether vision can be improved depends on the tumor size and if vision was already lost before the treatment.
In cases of vision loss, the treatment keeps the eye in place, which is preferable to prosthesis. In cases of advanced retinoblastoma, removing one eye when the fellow eye is intact allows the child to have fully functional vision and is a lifesaving procedure. The interventional treatment is especially important in bilateral retinoblastoma, where vision could be lost entirely.
Retinoblastoma tumors start in the retina, the back portion of the eye, and are caused by a gene mutation. They occur once in every 15,000 to 16,000 births. In most cases, the mutation occurs in a single cell in the eye so only that eye develops a tumor. Scientists do not yet know why these sporadic mutations occur. If left untreated, the tumors can spread to the brain via the optic nerve. One half of children who develop this cancer will die.
In the United States, about 300 children and adolescents are diagnosed with retinoblastoma each year, with almost two thirds of all cases occurring before the age of 2, according to National Cancer Institute statistics. It is often discovered before the age of 3 at an advanced stage because young children do not complain about loss of vision in only one eye. By the time white discoloration of the pupil is noticeable, the tumor is already large.
“We are hopeful that this interventional treatment may avoid removal of the eye in advanced tumors and even replace conventional [whole body] chemotherapy and radiation therapy in less advanced forms of retinoblastoma. Our work comes from the collaboration between an interventional radiologist, an ophthalmologist specialist in cancer, and a pediatric oncologist. Modern medicine is so complex that new treatments are often discovered by physicians working in a team,” explained Gobin.
Abstract 60, “A Phase I/II Study of Intra-Arterial (Ophthalmic Artery) Chemotherapy for Intraocular Retinoblastoma,” is available online at www.SIRmeeting.org.
UFE Treatment Often Overlooked by Gynecologists
Presented at SIR’s annual meeting, a study of 105 patients in the Atlanta metropolitan area shows that only 18% of women who saw a private practice gynecologist were told about uterine fibroid embolization (UFE), sometimes referred to as uterine artery embolization (UAE). UFE is a safe, effective, established treatment that has been widely available for the past decade and is covered by insurance. The majority of women who sought treatment from their private practice gynecologists for uterine fibroids were only offered hysterectomy or myomectomy surgery.
“The scientific evidence of the safety and efficacy of UFE is irrefutable. In medicine, we present the scientific proof at meetings like this in large groups, but we implement these results as individual physicians. Physicians need to incorporate UFE into the treatment algorithm for patients suffering with uterine fibroids. The patient should not have to be the one to suggest her treatment; that is the physician’s responsibility,” said John C. Lipman, MD, director of interventional radiology at Emory-Adventist Hospital in Atlanta.
With UFE, an interventional radiologist inserts a catheter into the femoral artery. Using real-time imaging, the physician guides the catheter up the artery and then releases tiny particles that are the size of grains of sand into the blood vessels feeding the fibroid. The particles cut off the fibroid’s blood supply, causing it to shrink and die, and relieving the patient’s symptoms. Most women return home the next day and can resume normal activities. There is less risk of serious complication with UFE, and complication rates are lower than those of hysterectomy and myomectomy.
Of the women who self-referred to interventional radiologists, the majority found out about UFE on their own, primarily through the Internet or a media advertisement. In some cases, they obtained referrals from their gynecologists but only after asking about the treatment.
Of the 600,000 hysterectomies performed annually in the United States, one third are to relieve symptoms caused by benign fibroids. Uterine fibroids can cause prolonged, heavy menstrual bleeding severe enough to cause anemia or require transfusion, disabling pelvic pain and pressure, urinary frequency, pain during intercourse, miscarriage, interference with fertility, and an abnormally large uterus resembling pregnancy.
Despite evidence of the long-term safety and efficacy of UFE, the hysterectomy numbers in the United States have changed very little in the past decade. Of all the available treatment options studied for fibroids, the largest published series is the Uterine Artery Embolization Fibroid Registry, which has published information on the UFE treatment of more than 3,000 women. The three-year data from this trial was recently published in Obstetrics & Gynecology.
“Women suffering with fibroids need to be given all of their options, not just the ones that gynecologists can offer. With UFE, my patients are treated as outpatients with no hospital stay. They go home with a band-aid and, on average, recover in four to five days. Many of the surgical patients after hysterectomy are still in the hospital by the time my UFE patients have recovered, and these surgical patients still have six to eight weeks of additional recovery at home,” noted Lipman.
Abstract 143, “Community Awareness of UAE as a Treatment Option for Women Suffering With Symptomatic Fibroids,” is available online at www.SIRmeeting.org.
Vertebroplasty for Osteoporotic Spinal Fractures Provides Relief, Decreases Disability
A five-year follow-up study of 884 osteoporosis patients bolsters the use of vertebroplasty for osteoporotic spinal fractures, finding that the procedure provides dramatic pain relief and sustained benefit. The results were presented at SIR’s annual scientific meeting.
“These data provide good news for physicians and osteoporosis patients,” said Giovanni C. Anselmetti, MD, an interventional radiologist at the Institute for Cancer Research and Treatment in Turin, Italy. “Many osteoporosis patients with compression fractures are in terrible pain and have a greatly diminished ability to perform basic daily activities such as dressing themselves.”
The average pretreatment pain score on the 11-point Visual Analog Scale was 7.9 +/- 1.5, and it dropped significantly to an average of 1.3 +/- 1.8 after the vertebroplasty treatment. Patients’ ability to manage everyday life, such as washing, dressing, or standing, was measured by the commonly used Oswestry Disability Questionnaire, completed by patients before and again one month after vertebroplasty. The scores changed from an average of 69.3% +/- 13.5% to 18.8% +/- 6.9%, showing a highly significant improvement in mobility.
Vertebroplasty is an outpatient procedure performed under x-ray imaging guidance and conscious sedation. The interventional radiologist inserts a needle through a nick in the skin of the back, directing it under fluoroscopy into the fractured vertebra. The physician then injects medical-grade bone cement into the vertebra. The cement hardens within about 15 minutes and stabilizes the fracture, an effect similar to that of an internal cast. The procedure is indicated for painful vertebral compression fractures that fail to respond to conventional medical therapies, such as analgesics offering limited pain relief or narcotic doses that are intolerable.
“Osteoporosis patients who have persistent spinal pain lasting more than three months should consult an interventional radiologist, and those who require constant narcotic pain relief should seek help immediately,” noted Anselmetti.
The study also showed that vertebroplasty does not increase the risk of fracture in nearby vertebra. “Vertebroplasty is already known to be a safe and effective treatment for osteoporotic vertebral fractures. Osteoporosis patients remain susceptible to new fractures, which often occur in the contiguous vertebra to an existing fracture. Our large-scale study shows that vertebroplasty does not increase the risk of fracture in the level contiguous to previously treated vertebrae and that these new fractures occur at the same rate as they would in osteoporosis patients who did not have vertebroplasty,” added Anselmetti.
The treatment was completed in all patients without major complications and with good clinical results. The treatment is widely available in the United States at all major institutions and many smaller institutions and is generally covered by health insurance.
Abstract 182, “Percutaneous Vertebroplasty in the Osteoporotic Patients: 5 Years Prospective Follow-Up in 884 Consecutive Patients,” is available online at www.SIRmeeting.org.