The $100 million ISCHEMIA Trial, the largest and best-controlled study on the subject to date, was presented at the American Heart Association’s annual scientific conference on November 16, 2019 in Philadelphia. It followed 5,179 high-risk patients and showed that after four years, surgical treatments (stents or coronary artery bypass surgery) were not more effective than lifestyle changes and medication in preventing heart attack deaths in patients with stable heart disease. More than 9.4 million North Americans today suffer from coronary artery disease and 650,000 die from heart attacks each year. Everyone should take notice of the ISCHEMIA results because:
• coronary artery bypass surgery is so extensive that it takes up to a year for a patient to recover from the surgery, and
• stents increase risk for future heart attacks and strokes, so people with stents usually must take anti-clotting medications for the rest of their lives.
The ISCHEMIA Trial enrolled participants from 37 countries who had treadmill stress tests that showed “ischemia,” partially blocked blood flow to the heart. More than 75 percent of the participants also had tests showing obstruction in their heart arteries. People who did not have narrowing of their coronary arteries were not included in the study. The patients were randomly placed in groups to receive either bypass surgery, drug-eluting stent procedures, or medication plus instruction on lifestyle changes. After four years, there was no difference in
• rate of heart attacks,
• deaths from heart attacks,
• resuscitation after the heart stopped beating, or
• hospitalization for chest pain or heart failure.
Differences between the groups that occurred earlier evened out later in the study. After six months, the surgically-treated groups had a significantly higher rate of heart attacks, but after four years they had a slightly lower rate of heart attacks. The earlier increased risk for death at six months was balanced by the later decreased risk of death at four years to make the total death rate the same after four years.The surgeries were more effective in patients with severe chest pain during exercise (“angina”). The ISCHEMIA Trial participants will be followed for another five years to provide more long-term data.
Other Studies Comparing Surgeries and Lifestyle Changes
• The EXCEL Trial showed that after five years, there was no significant difference between stents and bypass surgeries in death rates, strokes, or heart attacks (N Engl J Med, Sept, 2019; 381:1820-1830).
• The ORBITA study showed that in patients with medically-treated heart pain and severe heart artery blockage, stents did not increase exercise time more than a placebo procedure (Lancet, Jan 6, 2018;391(10115):31-40). This study did show that stents and bypass surgery are more effective than just taking medications and changing lifestyle risk factors to relieve the heart pain called angina, as did the ISCHEMIA Trial.
• The COURAGE Trial showed that in patients with stable angina, stents did not reduce the risk of death, heart attacks, or other major heart problems when added to optimal medical therapy (N Engl J Med, April 12, 2007;356:1503-1516). Patients also did just as well with medical treatment (drugs, exercise and a high-plant diet that restricted sugared drinks, sugar-added foods, red meat and fried foods) as they did with bypass surgery.
• A review of 11 randomized trials involving the follow-up of 11,518 patients with plaques in multiple arteries leading to their hearts showed that those who had bypass surgery were less likely to die than those who had stents (Lancet, Mar 10, 2018; 391(10124):939-48).
Stents Should Be Used within Three Hours of a Heart Attack
A heart attack is caused by sudden complete blockage of all blood flow that deprives a part of the heart muscle of all oxygen. Heart attacks are usually caused by a breaking off of plaque from the inner lining of a heart artery, followed by bleeding and clotting, and then the clot can extend to block completely all flow of blood to part of the heart muscle. If blood flow and oxygen are not supplied to the heart muscle within three hours, the heart muscle dies and is replaced by scar tissue that cannot contract and pump blood. During a heart attack, the heart may stop pumping blood to the body and the person can die. To save a person’s life, a doctor inserts a tube through the arm or leg into the heart artery, uses a balloon to open the blocked artery and then places a stent in the widened area to keep the artery from closing again. Some doctors place stents in heart arteries just because a patient suffers chest pain when exercising or climbing stairs, and there is data to show that stents can decrease chest pain on exertion.
In bypass surgery, a surgeon moves blood vessels from other parts of the body to bring blood to the heart muscle to “bypass” the blocked heart arteries. There is data to show that bypass surgery can prevent heart attacks and chest pain.
Comparing Stents and Bypass Heart Surgery
Stents have been proven to be of benefit for:
• sudden blockage of an artery leading to the heart,
• blockage of one heart artery, and
• in some non-diabetics, blockage of up to two arteries.
Bypass heart surgery may be indicated to increase blood flow to the heart when the doctor feels that symptoms are too severe to wait for medical treatment and lifestyle changes:
• heart failure,
• angina not controllable medically,
• blocked blood vessels that need to be opened immediately, or
• when medical treatment is not likely to be effective, such as having three or more blocked arteries. Generally, bypass patients are less likely than stent patients to need repeat surgery (N Engl J Med, March 26, 2015;372:1204-1212).
Since 50 percent of all North Americans will eventually suffer from heart and blood vessel disease (Circulation, Jan 2019;139(10):e56-e525), everyone should follow the rules for preventing heart attacks to avoid being put into a position where they have to be considered for treatment with stents or bypass surgery. The ISCHEMIA Trial shows that lifestyle changes plus medication are as effective as surgical procedures in treating many, but not all, people who suffer from stable heart disease. For a detailed list of risk factors for heart disease, lifestyle changes to help prevent and treat heart disease, and a discussion on statin drugs, see my report on Heart Attack Prevention