February 23, 2009
ISET Reporter’s Notebook
Vol. 10 No. 4 P. 18
Editor’s Note: This article was based on material provided by the media relations staff of the International Symposium on Endovascular Therapy from its meeting last month in Hollywood, Fla.
Study Looks at Stents for Stroke Treatment, Not Just Prevention
Stents can be placed in the brain to treat a stroke as it’s occurring, suggest preliminary data that was presented at the annual International Symposium on Endovascular Therapy.
Stents have long been used to open blocked blood vessels in the heart to prevent heart attacks and in the neck to prevent strokes. More recently, stents have been used in the heart to treat occurring heart attacks by opening up the blocked arteries. This early research suggests stents also can be used to treat occurring strokes by opening up blocked arteries in the brain.
Treatments for ischemic stroke currently include delivering clot-busting drugs to the blockage site through the veins or directly into the clot through an artery, or by removing the clot mechanically with a tiny corkscrewlike device on a catheter or vacuuming it out. But early research suggests stents may work better than those treatments.
“Most patients had significant improvement; for instance, they could go home rather than having to be placed in a nursing home, which is pretty dramatic,” said L. Nelson Hopkins, MD, a professor and the chairman of neurosurgery and a professor of radiology at the State University of New York at Buffalo, who presented the data. “Stents seem to work when clot busters or other mechanical devices can’t.”
The researchers reported preliminary results on 16 patients who received stents to treat their strokes as part of a single-center investigational device exemption from the FDA. Stents were placed and opened blocked arteries in the brain in all patients, and 11 patients (69%) had significant improvement in their stroke symptoms.
Researchers used CT perfusion to determine whether the use of a stent would be beneficial. “With CT perfusion, we can tell if the brain is dead or alive,” Hopkins said. “Some patients experience brain death within an hour; others can have a viable brain 24 hours after the stroke starts.” In those cases, it may still be possible to place a stent.
Liver Cancer Interventions
Using tiny chemotherapy-soaked beads to choke off and kill cancerous liver tumors is becoming more successful, according to research that was presented at the annual International Symposium on Endovascular Therapy.
Transarterial chemoembolization is a minimally invasive therapy that takes a two-pronged approach to treating cancer. Interventional physicians use minimally invasive methods to deliver the beads (also called microspheres) to the blood vessels that feed a tumor. The beads are combined with cancer-killing chemotherapeutic agents and then delivered to the blood vessels. The beads lodge in the blood vessels, blocking blood flow to the artery and cutting off the blood supply to the tumor. Several embolization studies presented at the symposium reported on research seeking to improve the treatment.
The most effective way to treat most cancerous tumors is by surgically removing them. However, more than two thirds of people with liver cancer aren’t candidates for surgery due to tumor size or location or because the tumor has grown into the blood vessels. Doctors have turned to other methods of treatment, including transarterial chemoembolization. Because the chemotherapy is delivered directly to the tumor rather than to the entire body as is the case with traditional chemotherapy, there are generally fewer side effects.
On average, only about one in four liver cancer patients is alive after two years. Although transarterial chemoembolization is typically used to slow the disease, not cure it, improvements in the beads are making it more effective and promising as a cure in some cases. Improvements include beads that absorb the chemotherapeutic agent (rather than just being mixed with it) and then release the drug once in the body, as well as modifications to bead uniformity and size, so they can more fully block the blood vessel and further guard against potential blood leakage that could feed the tumor.
Two Drugs Studied
A study at St. Joseph’s Hospital and Medical Center in Tampa, Fla., included 25 patients who had colorectal cancer that had spread to the liver and 11 with primary liver cancer. All of the patients with primary liver cancer received LC Beads that emitted doxorubicin, a type of chemotherapeutic agent, while 13 of the colorectal patients received doxorubicin-emitting beads and 12 received beads that emitted irinotecan, another chemotherapeutic agent. The patients who received the doxorubicin-eluting beads fared better. Ten of 11 (91%) of the primary liver cancer patients and 10 of the 13 (77%) colorectal patients were alive after two years. Conversely, one of 12 (8.3%) of the irinotecan patients were alive after two years. Researchers are studying why doxorubicin appears to work better in these cases.
LC Beads slowly elute the chemotherapeutic agent over the course of two weeks, providing a constant dose of the drug to the tumor without leading to systemic side effects.
“There is definitely a chance of cancer cure with this procedure beyond just palliation,” said Glenn Stambo, MD, vascular and interventional radiologist at St. Joseph’s Hospital. “The more isolated the tumor and its blood vessel feeders, the better the chance for a complete cure.”
A multicenter Italian trial used HepaSphere beads loaded with chemotherapeutic agents to deliver treatment to 53 patients with liver cancer. HepaSphere beads are designed to expand after they lodge in the arteries that feed the tumor, so that blood flow is more effectively blocked. These microspheres absorb the chemotherapeutic agent and then the drug is released directly into the tumor.
A month after treatment, tumors in 27 patients (51%) showed a complete response, 18 (34%) showed a partial response, and eight (15%) showed stable disease. Six months later, 19 of 34 patients (55.9%) had complete tumor response, eight (23.5%) had a partial response, and seven (20.5%) had growing disease. Of the remaining 19 patients, three died, four were lost at follow-up, and 12 receive other treatments.
“Patients who still had good liver function and who had tumors in only one lobe of the liver did better with this treatment,” said Maurizio Grosso, MD, chairman of the department of radiology at Santa Croce and Carle Hospital in Cuneo, Italy. “We’re hopeful that treatment with HepaSphere will be an improvement over traditional chemoembolization.”
Embolization Without Chemotherapy
Researchers at the European Institute of Oncology in Milan, Italy, are studying using embolization without chemotherapy for liver cancer. The study included 25 patients with 34 primary liver tumors. All patients received Embozene microspheres without the addition of any chemotherapeutic agents. The patients had 35 sessions with the microspheres.
After one month follow-up, 18 tumors (52%) had shrunk in size, while 16 (48%) were the same size with no tumor growth detected. In a group of 16 tumors with follow-up ranging between six and 12 months, two tumors (12%) completely disappeared, seven tumors (44%) continued to shrink, two (12%) were stable, and five (31%) grew, although they were still of a size suitable for new local treatments. To date, 14 patients have had more than one year of follow-up care, and 93% of them are still alive.
“One concern with embolization is that blocking the tumor-feeding vessels in some cases leads to restriction in blood flow and cell death,” said Franco Orsi, MD, chief of interventional radiology at the European Institute of Oncology. “One of the main benefits of Embozene microspheres is the precise, well-calibrated sizing, which match the small blood vessels that feed the tumors. The larger the particles used, the further away the embolization from the tumor and the less effective the treatment will be. Moreover, embolization without drugs usually causes few or no posttreatment side effects and the patient can usually be discharged the next day.”
Orsi noted that another important feature of this new material is its ability to prevent inflammatory reactions, which is one of the leading causes of tumor growth.
Comparing Radial and Femoral Access in Cardiac Interventions
New data presented at the annual International Symposium on Endovascular Therapy suggest that performing an angioplasty procedure by entering through the wrist, rather than traditional femoral access, will make it safer and easier on patients. The radial access translates to less bleeding, less downtime, lower costs, and less risk overall, particularly for obese patients, according to the data presented.
To access the arteries, an interventional physician typically makes a small incision in the groin and advances the catheter through the femoral artery to the blockage site to open the artery and often place a stent.
To reduce the risk of bleeding and nerve damage at the femoral artery access site, patients must lie down for two to six hours after treatment. Femoral access is particularly challenging and risky for obese people.
Accessing the blocked blood vessels through the wrist’s radial artery significantly reduces the risk of bleeding and nerve damage, suggest data on more than 5,000 procedures performed at Baptist Cardiac & Vascular Institute in Miami. The radial approach also is easier on patients because they can sit up after the procedure and walk away almost immediately. Currently, only about 2% of all minimally invasive heart treatments are performed using radial access.
“I believe 75% of patients would be candidates for the radial approach if it were an option,” said Ramon Quesada, MD, medical director of interventional cardiology at Baptist Cardiac & Vascular Institute. “The radial approach is a bit more technically challenging for physicians, but once they master it, I think most would prefer it. One of the main barriers is a lack of training opportunities.”
When the femoral access approach is used, there is a 2.8% risk of bleeding or nerve damage, according to studies. Most patients spend at least one night in the hospital after the procedure. Although rare, the bleeding can lead to kidney failure, blood infection, and death. At Baptist Cardiac & Vascular Institute, the complication rates for the radial approach are extremely low; only 0.3% of patients had bleeding complications, and none suffered nerve damage. An overnight stay may be advisable, depending on the complexity of the intervention performed, not because of the access approach.
The radial approach isn’t appropriate for all patients, including those who have very small or twisted arteries or are extremely thin, said Quesada.
“Using the radial approach results in lower cost, less time before the patient can get up and walk around, and fewer complications,” said Quesada. “Patients who are ideal candidates for the radial approach are those who are obese or have severe peripheral arterial disease.”