Opening Totally Blocked Arteries May Improve Quality of Life
Restoring blood flow in the right patient can lessen chest pain, shortness of breath and fatigue.
When blockages in the coronary arteries impair blood flow to the heart muscle, patients can experience chest pain (angina), fatigue and shortness of breath that may not be relieved by medication. When this occurs, angioplasty and stenting (percutaneous coronary intervention, or PCI) or coronary artery bypass grafting (CABG) may be advised to help manage symptoms.
Yet about 30 percent of cardiac catheterizations performed in patients with stable coronary artery disease show evidence of a chronic total occlusion (CTO). In this situation, blood flow through a coronary artery has been totally blocked for more than three months. Studies have shown that when more than 10 percent of the heart muscle is affected by a CTO, the patient has a significantly higher risk of death or major adverse cardiac event. These patients often suffer from angina that is severe enough to impact their quality of life.
Cardiologists generally do not attempt to open such blockages, because success rates are typically low, the risk of complications is high and evidence of benefit has been lacking. Instead, these patients may be told to continue treating their symptoms with medications, because there are no alternatives. But this is not entirely true.
New Thinking About Blockages
Cleveland Clinic researchers studied the issue closely and found that patients who meet certain criteria may gain tremendous benefit from CTO revascularization.
"We have learned that opening the artery and restoring blood flow can help patients feel much better," says Cleveland Clinic interventional cardiologist Jaikirshan Khatri, MD. "In patients with CTO-related angina that does not respond to medical therapy, PCI can produce symptom relief similar to that obtained by CABG and reduce rates of all-cause mortality, major adverse cardiac events and the need for subsequent CABG."
When heart muscle supplied by a CTO-affected artery is healthy, opening the CTO also has been shown to improve left ventricular function. "The heart regains some of its pumping strength," says Dr. Khatri.
Identifying which patients will benefit from having a CTO opened with PCI is challenging. Angiography-moving X-rays taken during a cardiac catheterization-is not sufficient.
"We use other techniques to help us understand the risk-benefit ratio of PCI versus medical management," Dr. Khatri explains. "We also can use myocardial perfusion imaging to obtain a noninvasive assessment of how much heart tissue is affected by the CTO. If it's more than 12.5 percent, we know PCI is likely to produce significant improvement in symptoms."
A Steep Learning Curve
Due to the difficulty of performing CTO PCI, many cardiologists will not try it.
Overall, attempts are made to open only about 5 percent of CTOs with PCI. The success rate is only 59 percent. But at Cleveland Clinic and other high-volume centers with experienced interventionalists, the success rate is as high as 92.9 percent.
"There is a strong correlation between a center's CTO PCI volume and success rates, because there is a steep and long learning curve," says Dr. Khatri.
Dr. Khatri and his colleagues collectively perform more than 100 CTO PCIs every year. The large number of patients enables them to research techniques to simplify and improve the safety of CTO PCI. For example, they conduct the procedure through an artery in the wrist, which greatly reduces the risk of a life threatening bleed.
"We hope to get the technique and technology good enough that it becomes a routine procedure with high safety and success rates," he says.
The Bottom Line
The important thing to know, says Dr. Khatri, is that if you have a totally blocked coronary artery that produces symptoms that cannot be managed medically, there is a treatment option.
"Most patients with a complete blockage are told that nothing can be done, and that's wrong," he says. "CTO PCI is a relatively specialized procedure that gets better results in experienced hands, but in the right patient, it can have many beneficial effects."