Patients that received drug therapy alone, with no surgery, for blocked arteries did not have any more heart attacks than those that did have surgery, the research found, challenging decades of common medical knowledge.

In a study with more than 5,000 people, the most tangible benefit of surgeries like bypasses and stents was helping people with chest pain, or angina. 

"You would think that if you fix the blockage the patient will feel better or do better," said Dr. Alice Jacobs, director of Cath Lab and Interventional Cardiology at Boston University to The New York Times.

The study, she said, "certainly will challenge our clinical thinking."

Another doctor estimated to the Times that patients choosing drug therapy over surgery could save roughly $775 million a year.

The $100 million trial was presented Saturday at the annual meeting of the American Heart Association, and is the latest addition to a divide between specialists over how to treat artery blockages.

Stents and other artery-clearing devices have been challenged for years, but this research, called Ischemia, was the most in-depth and controlled, doctors told the Times.

"This is an extraordinarily important trial," Dr. Glenn Levine, director of cardiac care at Baylor College of Medicine in Houston told the Times.