A new rating scale can help physicians predict whether patients will feel better if their clogged heart arteries are opened non-surgically or with a major bypass operation, researchers report in Circulation: Journal of the American Heart Association.
Although both angioplasty and bypass surgery can improve blood flow to patients’ hearts, the principal limitation of angioplasty is a ‘reclogging’ or ‘restenosis’ after the procedure. The main limitation of bypass surgery is the invasiveness and recovery time after the operation, said John Spertus, M.D., M.P.H., director of cardiovascular education and outcomes research at the Mid-America Heart Institute in Kansas City, Mo.
Previous studies comparing the two approaches have shown that people’s health status is better, on average, after bypass surgery, he added. The researchers used a scale to predict the likelihood of restenosis after angioplasty and compared the outcomes after angioplasty and bypass surgery by the patients’ risk for restenosis.
“We found that patients at intermediate and high risk of restenosis are far more likely to get more benefits from bypass surgery while those at lower risk will do fine without undergoing major surgery,” Spertus said.
Coronary artery bypass surgery reroutes blood around clogged arteries to improve blood flow and oxygen to heart muscle. Surgeons use a segment of healthy blood vessel from another part of the body and create a detour, or bypass, around each blocked portion of artery. Patients usually stay in the hospital at least three days; full recovery may take months.
Angioplasty, an alternative to bypass, is a non-surgical procedure to open a blocked artery, usually by inserting a wire mesh tube called a stent. Physicians thread a catheter with a deflated balloon on its tip through a blood vessel in the arm or leg and into a blocked artery in the heart. When the blockage is reached, the balloon is inflated. This pushes plaque to the side and stretches the artery wider so blood can flow more easily. In some angioplasty procedures, the catheter has a wire mesh stent on the balloon. When the balloon is inflated, the stent opens and locks in position to keep the artery open. After angioplasty, patients usually stay in the hospital at least one night and are told to avoid vigorous activity for a few days.
Both procedures help reduce heart-related chest pain (angina) and the risk of a heart attack. Deciding which one to use depends on technical considerations as well as a patient’s condition and preferences.
The researchers examined the occurrence of angina and quality of life one year after 1,027 patients were treated with angioplasty (83 percent included stents) and 432 with bypass surgery in 1999-2000. This scale was not used when patients were originally assigned to have bypass or angioplasty, but was applied upon review of their medical records.
Researchers divided the patients into three groups based on their pre-procedure scores on a scale that predicts the risk that a stent-widened portion of artery would narrow again.
The pre-procedure scale considers eight characteristics that raise, to various degrees, the risk of restenosis. Four points are given for diabetes, needing a procedure because of an acute heart attack or having a heart attack in the past 24 hours. Daily chest pain or being younger than age 55 is worth three points. Two points are given for having weekly/monthly chest pain, having an angioplasty in the past, or being male. One point is given for blockage in more than one coronary artery.
In the 546 patients with a score of four or less, considered to have a low (15 percent) risk of restenosis within one year, the researchers found no benefit to bypass over the easier angioplasty procedure. In the 678 patients with a score between 5 and 8, with an intermediate (23 percent) risk of restenosis, angina relief was significantly better after bypass surgery than angioplasty.
The greatest advantage in bypass over angioplasty was seen in the 235 patients who started with a high (44 percent) risk of restenosis, scoring more than 8 on the restenosis scale. High-risk patients who underwent bypass had far better scores for angina and quality of life than those who had angioplasty.
The study shows that the patient’s experience of their disease and their quality of life is really influenced by whether angioplasty will be sustained and durable, Spertus said. Patients who are less likely to have a durable result will have lower, on average, control of their symptoms and lower quality of life with angioplasty.