A Tale of Two Heart Procedures
The trend in health care is toward less invasive procedures that seek to minimize the risks of surgery. When it comes to treating advanced heart disease, however, new research shows that the scalpel has the edge—except when it doesn’t
Dr. Stephen Fremes is lead author of an influential study comparing coronary artery bypass graft surgery—CABG, pronounced “cabbage”—with angioplasty for patients with advanced heart disease.
Photo: Curtis Lantinga
In 2009, a team of researchers, including U.S. and Egyptian cardiologists, did a study using cross-sectional X-ray pictures of 20 mummies displayed at the Museum of Egyptian Antiquities in Cairo, Egypt.
The bad news: more people die of diseases of the heart and blood vessels each year than from any other cause. The good news: the number of people dying from cardiovascular disease has declined steadily since the 1960s, thanks to advances in research. Following are some life-saving breakthroughs in cardiovascular science from the 20th century.
Electrocardiography
In the early 1900s, Willem Einthoven, a Dutch doctor and physiologist, invented the electrocardiograph, the first practical device to record the heart’s electrical activity. He went on to describe early stages of heart failure, arrhythmia (abnormal heart beat) and other cardiac disorders.
Coronary angiography
This technique uses X-rays and a dye to let doctors see inside coronary blood vessels. In 1941, André Cournand and Dickinson Richards, researchers at Columbia University in New York City, New York, used the catheter as a diagnostic tool for the first time to measure cardiac output.
Preventive cardiology
The Framingham study, published in 1961, looked at development of heart disease in thousands of residents of Framingham, Massachusetts. It set the concept of risk factors, such as high blood pressure, smoking and high cholesterol, providing clinicians with profiles for cardiovascular disease and identifying people who might benefit from preventive measures.
Coronary artery bypass graft surgery
In May 1967, René Favaloro, an Argentine surgeon, used part of the saphenous vein, which runs along the length of the leg, to replace a blocked segment of the right coronary artery. Later that year, he used the saphenous vein to reroute blood around obstructions. Coronary artery bypass graft surgery is one of the most common major surgeries in the U.S. and Canada.
Automatic implantable cardiac defibrillator
This device is placed in the chest to monitor heart rhythms. It uses electric shocks to treat dangerous arrhythmias, especially those that can cause the heart to stop beating suddenly. A team of researchers at Sinai Hospital in Baltimore, Maryland, began working on the device in 1969. Eleven years later the first patient was treated with it.
Coronary angioplasty
On Sept. 16, 1977, German cardiologist Andreas Gruentzig performed the first balloon angioplasty on the human heart. His patient, a 37-year-old man, remained awake. It was a success: Gruentzig opened the narrowed artery in two quick balloon inflations. In Canada, the rate at which doctors performed angioplasties doubled between 1995 and 2005, from 25,000 to 50,000.
Among the 16 mummies—some aged as old as 3,500 years—whose arteries and hearts could be identified, nine had calcification in the arteries or in the path of where the arteries should have been. That atherosclerosis (plaque build-up in and on artery walls) was detected in these mummies suggests that heart disease isn’t a malady of the modern era.
Today, heart disease is the number one cause of death globally. In Canada, cardiovascular disease, comprising disorders of the heart and blood vessels, is the leading cause of hospitalization.
The most common form of heart disease is coronary artery disease, when the thoroughfares supplying blood to the heart become blocked or narrow. For these patients, medicine is the best way of reducing the chance of heart attack or death, says Dr. Harindra Wijeysundera, a scientist in the Schulich Heart Research Program at Sunnybrook Research Institute (SRI) and an interventional cardiologist at Sunnybrook Health Sciences Centre.
In addition to drugs, patients can undergo one of two procedures to restore blood flow to the heart. One option is coronary artery bypass graft surgery (CABG, pronounced “cabbage”), in which doctors open a patient’s chest and sew a healthy artery from the chest or leg to the diseased vessel, thereby bypassing the blockage and rerouting blood to the heart.
Percutaneous coronary intervention (PCI), or angioplasty, is another option. This is a nonsurgical procedure in which an interventional cardiologist makes a small puncture in the groin or arm, and under X-ray guidance threads a catheter with a balloon at its tip to the blockage. The balloon is inflated to widen the artery; sometimes a small mesh tube called a stent is inserted to prop the vessel open.
The trouble is, it’s not clear which is better for certain patients. “It’s a question that comes up frequently and something that cardiologists and cardiovascular surgeons discuss often with their patients,” says Wijeysundera. “Is any form of revascularization needed? What are the benefits of it? And if it is needed, which of the two—PCI or CABG—is most appropriate? For patients who are having a heart attack or have blockages in only one artery, PCI is recommended. However, in advanced coronary disease, there is debate.”
Dr. Harindra Wijeysundera, in the catheterization lab at Sunnybrook, tries to clear a blocked artery in a patient with heart disease, working with fellow interventional cardiologist Dr. Brad Strauss.
Photo: Curtis Lantinga
Advanced heart disease includes unprotected left main disease, where there is more than 50% narrowing of the left main coronary artery; narrowing of two or more coronary arteries; blocked arteries and diabetes; and coronary artery disease and left ventricular dysfunction, a sign of heart failure. Historically, surgery was the main treatment. Over time, however, PCI gained traction and was used to treat advanced coronary disease, says Dr. Stephen Fremes, a scientist in the Schulich Heart Research Program at SRI, cardiovascular surgeon at Sunnybrook and professor at the University of Toronto.
To provide evidence-based recommendations on which therapy is better for specific patients, Fremes, Wijeysundera and clinical colleagues did a study comparing the effectiveness of CABG surgery with angioplasty. It was published in the Journal of the American Medical Association in November 2013.
The study summarizes results of research published in the last six years that compared the two procedures in patients with advanced heart disease. The researchers looked at which treatment was associated with adverse events.
They found clear benefits to surgery. “The end points we looked at were hard end points: mortality, myocardial infarction [heart attack], stroke and secondary revascularization. In terms of hard clinical outcomes, surgery is better but much more invasive than angioplasty,” says Fremes, the study’s lead author. They noted, however, that where severity of disease is less complex, or there is a high surgical risk due to advanced age or other health conditions, PCI should be considered.
Percutaneous coronary interventions have evolved since the first coronary angioplasty was performed in 1977. [See sidebar.] In the decades since the inception of PCI, the devices it uses have become smaller and more maneuverable. Success rates have risen, as has the number of procedures carried out. In 1980, 1,000 angioplasties were done worldwide; in 1997, this figure soared to one million, making it one of the most common interventions.
Although PCI is less invasive, it is not without risk. A small percentage of people with stents in their arteries develop a blood clot, which can cause a heart attack or stroke. For this reason, angioplasty candidates must take blood thinners, says Wijeysundera, who performs between 250 and 300 angioplasties annually. Other risks include bleeding, heart attack and stroke; the risk of the last two is low, occurring in less than 1% of procedures. “The biggest drawback, and what our review showed is there’s a higher likelihood of [patients] needing more procedures down the road compared to bypass surgery,” he says.
In the study, the researchers also emphasized a collaborative model of care in which cardiologists, interventionalists and surgeons discuss the patient’s complexity of disease, overall health and treatment preference. “When the surgical risk gets to be too high, the relative advantage of CABG versus PCI changes. That’s part of the ‘heart team’ approach—to try and determine what the surgical risk is,” says Fremes.
At Sunnybrook, many of the angioplasties performed are on patients who have just had a heart attack. In such cases PCI is the best option, notes Wijeysundera, who is also a professor at U of T: “There’s really no debate in the literature about what they should get, because it’s an emergency situation and they have disease that is focal to one artery that’s caused their problem.”
In treating patients for whom either surgery or PCI is viable, the heart team approach comes into play. This is important because once patients are given all of the pertinent information, the decision of which treatment to choose is up to them, says Wijeysundera.
John Russ Smith chose to have bypass graft surgery in December 2005 at the age of 71. A lifelong athlete, Smith enjoyed good health and played in a workplace baseball league for 25 years.
Due to high blood pressure, Smith was referred to a cardiologist. During an angiogram (an imaging test that uses X-rays and a dye to let doctors see inside blood vessels) Smith learned he had heart disease. “I’ve never had chest pain. I’m watching this black ink go through the arteries, and two of them stopped completely, and the other was 50%,” he recalls.
He was shocked to learn he had had two “silent” heart attacks, where blood flow to the heart is partially blocked and symptoms—if any—are few. He was referred to Fremes, who, along with Smith’s cardiologist, recommended bypass surgery as he was at risk of a potentially fatal heart attack. Fremes performed the surgery.
“He did a miraculous job. It’s a very invasive solution. You wouldn’t know it if you looked at me now. I’m forever grateful,” says Smith. He had no complications, and his recovery was quick. A few days after the operation, he could walk around. At his three-month follow-up there was one thing on his mind: could he play baseball?
Fremes reluctantly gave the green light but cautioned him to be careful. Smith, who covers third base or “the hot corner,” played all 42 games of the 2006 season, which was his last. “I went out in a blaze of glory because we won a championship,” he says. Now 80 years old, Smith has slowed down—a little. He works part-time in the insurance industry and has six grandchildren.
Although this study’s findings were clear, Fremes says research comparing the two procedures should be revisited every five years owing to new developments in the fields. He is participating in a large study evaluating a new PCI technology against surgery. The EXCEL clinical trial, slated for completion in 2021, will recruit 2,600 patients from centres across North America, of which Sunnybrook is one. In the meantime, Fremes wants their research to have broad clinical impact. “Hopefully there will be more interest [on the part of] those who refer [patients] to the cardiologists. That may affect the opinions of the original referring doctor to consider surgery rather than angioplasty more liberally.”
This research was supported by the Bernard S. Goldman Chair in Cardiovascular Surgery at Sunnybrook, Canadian Institutes of Health Research, and the Heart and Stroke Foundation of Canada.
