In unblocking chronic total occlusions (CTOs), experience helps, but only a handful of U.S. interventional cardiologists perform approximately 150 CTO recanalizations annually. Richard R. Heuser, MD, chief of cardiology and chief of the cardiac cath lab at St. Luke’s Hospital and Medical Center in Phoenix, is one of them.
Heuser spends a considerable amount of time training interventionalists to perform CTO PCIs, saying that facilities that perform open-heart surgery should attempt open CTOs. These centers should perform a minimum of 1,000 angioplasties annually. “If you’re not doing that many cases, it’s not worthwhile to stock the CTO specialized equipment,” he says. At a bare minimum, interventionalists should perform between 50 a nd 60 CTO PCIs per year and should attend training sessions.
In a study of 1,000 consecutive CTO PCIs performed between January 2004 and December 2009 by 13 operators, Lefevre et al found that operator experience—identified for the first time—was a strong predictor of success. The study was presented at TCT.10.
The main reason people get referred for open-heart surgery is due to the presence of a CTO, says Heuser. “With modern wires, catheters and techniques, we are able to open CTOs that we couldn’t a few years ago. Quality of life is very important in medicine today. Most of these patients have chronic angina. Opening the CTO may not help them live longer, but it will help improve their lives,” Heuser says.
While definitive data are lacking, several small studies have shown a mortality benefit associated with CTO PCI. In a recent single-center study of 302 patients, for example, Borgia et al found successful CTO recanalization not only improved angina, but also improved long-term cardiac survival and reduced major adverse cardiac events. The study also was presented at TCT.10.
The biggest breakthrough in opening CTOs is guidewire and catheter technology, says Steven J. Yakubov, MD, from MidOhio Cardiology and Vascular Consultants in Columbus, Ohio. Newer guidewires are very hydrophilic, enabling easier gliding to the CTO, while tapered tips allow improved entry into the occlusion. Also, hydrophobic wires facilitate entry into sites of most resistance and newer support catheters allow improved steering and crossing. “These technologies certainly impact the decision whether or not to attempt recanalization,” Yakubov says. “It’s made easier with the likelihood of success.”
Clinical indications for CTO PCI are straightforward: active chest pain despite therapy, cardiac function test indicating insufficient blood supply or hibernating myocardium that should be treated, says Yakubov. Angiographic features give some indication of whether the CTO recanalization will be successful. They include visible stump, lower calcification score and shorter occlusion length, which could be used as a predictive score of success.
Heuser and colleagues run a “radial first” lab, including using the radial approach to access difficult CTOs. In one case, for example, a 40-year-old man was referred to them with an occluded right coronary artery (RCA) that the referring interventionalists could not access via the femoral artery. “I entered through the wrist and crossed the CTO within 10 minutes,” Heuser says. “It’s predominately the RCA where the radial approach is effective, particularly if there are not extensive collaterals,” adding that radial access of the RCA allows imaging to “deeply engage the RCA more avidly than from the groin.”
Heuser has even used the Impella cardiac assist device (Abiomed) about half a dozen times, which is helpful if the patient is ischemic and has diminished ventricular function.
Hospitals that have CTO programs could attract patients that would otherwise be treated medically at another facility, says Heuser. These patients undergo many diagnostic procedures and the specialized CTO equipment is “not that expensive,” he says, adding that a CTO program benefits both the hospital and patients.