The new study found that patients who received drug therapy alone did not experience more heart attacks or die more often than those who also received bypass surgery or stents, tiny wire cages used to open narrowed arteries.

That finding held true for patients with several severely blocked coronary arteries. Stenting and bypass procedures, however, did help some patients with intractable chest pain, called 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. The study, she added, “certainly will challenge our clinical thinking.”