Just shy of 400 physicians and allied health care professionals gathered to discuss the latest trends and strategies for treating the toughest coronary blockages at the Seventh International Chronic Total Occlusion Summit, held February 4-5, 2010, in New York, NY.
Catheter-based treatments for chronic total occlusions (CTOs) are evolving, with more and more interventional cardiologists willing to attempt procedures. Despite this, undertreatment remains an issue.
Europe on the Move
Carlo Di Mario, MD, of the Royal Brompton Hospital (London, United Kingdom), presented details from the Euro CTO Club’s 2008-2009 registry. During that period, information was available for CTO procedures in 1,000 patients who were treated mostly in Italy, Germany, and the United Kingdom. The procedures were successful in 80% of cases, which took about 1 hour and 40 minutes to complete. The registry also documented low rates of in-hospital complications such as heart attack, cardiac death, and bleeding.
One important take-away message from the first annual meeting of the Euro CTO Club last year, Dr. Di Mario said, is that angioplasty for CTOs is not practiced enough in Europe. “Too often patients are left on medical therapy or sent to [bypass surgery].” Remedies include increased training as well as changing cardiologists’ mindset so that complex cases are sent to experienced hospitals.
“We are moving as a club towards a real trial of [angioplasty] versus medical therapy,” he said.
Modest Improvements Seen in the United States
In his presentation on the US experience, J. Aaron Grantham, MD, of Saint Luke’s Mid America Heart Institute (Kansas City, MO), shared results gathered from the National Cardiovascular Disease Registry. The findings were published in the June 2009 issue of JACC: Cardiovascular Interventions. The registry first began looking at patients treated between January 2004 and March 2005. Since then, it has been updated annually.
The first group, treated in 2004-2005, included over 35,000 patients with CTOs. Among them, nearly 5,000 patients received angioplasty. By 2008, physicians were less likely to try angioplasty but success rates had increased. Clinical outcomes held steady. Most cases were diagnosed in hospitals that saw relatively few patients with the condition. Hospitals that saw the lowest number were less likely to try angioplasty than those who saw more CTO cases. The procedure was also more likely to be done in patients with heart disease in only 1 coronary vessel.
“US CTO angioplasty attempt rates are not increasing measurably, but success rates are improving modestly,” Dr. Grantham concluded, adding that the procedure appears safe. On the downside, he noted, the fact that physicians with less experience are less likely to attempt angioplasty suggests that patients do not have equal access to care.
Promising New Tools Await Clinical Validation
Several presentations highlighted innovative technologies that are starting to move from preclinical testing to patient care.
For example, the Crosser catheter uses high-frequency mechanical vibration at its tip to pulverize calcified atherosclerotic plaque. This facilitates navigation of a guidewire through the blockage. Alfredo R. Galassi, MD, of the University of Catania/Ferrarotto Hospital (Catania, Italy), and colleagues recently compared the Crosser system with conventional wire devices as a front-line strategy in complex cases. Although Crosser-treated lesions tended to be longer than those treated with conventional wires, rates of procedural success and major complications were similar for the two approaches, while the average procedure time was shorter with the Crosser device. In addition, no perforations of the vessel occurred with the Crosser.
Amit Segev, MD, of Chaim Sheba Medical Center (Tel Hashomer, Israel), discussed the CiTop ExPander guidewire. Manipulating the tip of this stainless steel guidewire enables it to bore tiny channels through occlusions with a low risk of perforation. The CiTop showed its mettle in a small ‘first-in-man’ study, with an average time needed to cross blockages of only 14 minutes. There were no mechanical problems with the wire and no device-related adverse events, Dr. Segev reported.
The recently FDA-approved Enabler-P peripheral system uses cycles of balloon inflation and deflation to help propel the guidewire forward with increasing force. The safety and effectiveness of the system are currently being evaluated in CTOs in certain leg arteries. According to Maurice Buchbinder, MD, of the Foundation for Cardiovascular Medicine (La Jolla, CA), crossing proved successful in 15 of 16 patients with an average crossing time of only 2 minutes. There were no serious adverse events.
R. Michael Wyman, MD, of Torrance Memorial Medical Center (Torrance, CA), reviewed experience with the CrossBoss, which includes a catheter with a guidewire tip advanced by a spin technique and a balloon that reorients the guidewire toward the main channel of the vessel if it strays.
Results of a ‘first-in-man’ study of 49 patients showed a technical success rate of 83.7% and a low rate of major complications at 30 days. The procedure took an average of about 100 minutes. A multicenter clinical trial is now underway in stubborn blockages comparing outcomes using the BridgePoint system with previous experience using conventional technology. In initial results from his institution, Dr. Wyman reported, blockages were successfully crossed in 77% of patients, and the average procedure time was 93 minutes.
