In patients with a complete blockage in the heart's arteries that persists over time, treatment with medications alone was found to be equal to percutaneous coronary intervention (PCI), a procedure to open blocked arteries, in terms of major adverse events over three years, according to a study presented at the American College of Cardiology's 66th Annual Scientific Session.
Overall, about 20 percent of patients died or experienced a non-fatal heart attack, stroke or subsequent revascularization procedure (such as PCI or bypass surgery)--which together comprised the trial's composite primary endpoint--within three years after enrolling in the study. That proportion was not significantly different for patients randomly assigned to receive PCI compared with those assigned to receive only drugs, which included aspirin, a beta-blocker, a calcium channel blocker and a statin.
The findings are in line with evidence from previous studies suggesting that PCI does not improve long-term patient outcomes compared with medications alone in patients with coronary heart disease (buildup of plaque in the heart's arteries, the most common form of heart disease) who have not experienced a sudden change in symptoms. This is the first study to compare clinical outcomes from the two treatment approaches in patients with a complete or near-complete blockage in the heart's arteries that persists over time, known as chronic total occlusion. Chronic total occlusion occurs in about a quarter of people with coronary heart disease and can cause chest pain, fatigue, shortness of breath and ischemia (damage that results when tissues are deprived of oxygen).
"PCI is not the only solution to treat chronic total occlusion, and in terms of patient outcomes, cost versus benefit, and other considerations, it is not beneficial to use PCI for all chronic total occlusion lesions," said Seung-Jung Park, MD, a cardiologist at Asan Medical Center in Seoul, South Korea, and the study's lead author. "The size of the ischemia, patient symptoms and cardiac function must be taken into account prior to the decision to perform PCI."
The trial aimed to shed light on whether PCI or medication alone should be used as a first-line treatment for patients with chronic total occlusion. In these patients, drugs can ease symptoms and reduce the risk of events such as heart attacks and strokes, but they do not remove the blockage. With PCI, doctors thread a thin wire to the blockage via an artery and then use a tiny balloon, and sometimes also a mesh tube called a stent, to open the artery and allow blood to flow freely. Although it is frequently used in patients with coronary artery disease, PCI is more complicated when one or more arteries is fully blocked, and it has been unclear whether doctors should first use PCI or drugs alone for these patients.
The researchers enrolled 815 patients with chronic total occlusion at 19 cardiac centers in Asia. They randomly assigned 417 patients to receive PCI plus drugs and 398 patients to receive drugs alone. After tracking outcomes for three years, the results revealed no significant differences in the composite primary endpoint and no differences in rates of death, heart attack, stroke and subsequent revascularization procedures considered separately. Measures of health-related quality of life, assessed by the Seattle Angina Questionnaire, also did not differ significantly between the two groups throughout the follow-up period.
According to researchers, the findings suggest that it is not always necessary to open blocked arteries using PCI, which substantially increases costs and also can increase the risk of a heart attack around the time of the procedure.
"If patients suffer from a large ischemic burden, PCI is crucial to open the lesion, but for small occlusions, optimal medical treatment [with drugs alone] is sufficient," Park said.
Park pointed to two potential reasons why patients with total occlusion might not benefit from opening the blockage. If a blockage builds up over a long period of time, sometimes a patient will develop new blood vessels that allow blood to circumvent the blockage, akin to a "natural bypass." It is also possible that a total blockage actually carries a lower risk of heart attack or stroke compared with a partial blockage. Because no blood is flowing through the blockage, it may be less likely to rupture and travel through the bloodstream to the heart or brain compared with plaque that lines, but does not block, the artery.
Due to slow enrollment, the study stopped enrollment after 815 patients instead of 1,284 patients, as was originally planned. Park said interventional cardiologists may have been reluctant to enroll patients because of the predominant view that blocked arteries should be opened, despite a lack of evidence for long-term benefits of the intervention in these patients. Nonetheless, statisticians determined that the study was sufficiently large to show statistically valid results.
Park suggested that a large, global, multi-center study would allow researchers to further validate the study findings.