Although invasive procedures improved chest pain and quality of life in some patients, several important outcomes did not differ significantly – namely, subsequent heart attack, hospitalization for unstable chest pain or heart failure, resuscitation after cardiac arrest, and death from cardiovascular causes.
"Patients want to know, will this treatment make me live longer?" said study chair Dr. Judith Hochman, senior associate dean of clinical science at NYU Langone Health. "Based on what we saw, we saw no evidence that would lead them to live longer."
Stents and bypass surgery are commonly used for heart attack patients, but the issue of intervening with stable patients – who have blockages or chest pain during exercise but not an acute heart attack – have been hotly debated.
Patients who had a heart attack were not included in the study, nor other groups, including those with poor heart muscle function or narrowing of the main coronary artery of the heart.
But when it comes to patients with stable heart disease, "we selected patients with a very abnormal stress test," explained Hochman. "It was believed that if someone would benefit from an invasive stent or bypass implant surgery strategy, those would benefit."
The international study, launched in 2012, included more than 5,000 patients in 37 countries, making it the largest study of its kind, the researchers said. Hochman said it is based on two previous studies that drew similar conclusions, but partly because of their design, failed to gain greater acceptance among doctors.
If asymptomatic patients renounce invasive therapies, Hochman estimates the savings could reach hundreds of millions of dollars in the United States, based on previous research.
"The implications are quite large worldwide and in the United States," she said.