Los Angeles ? Angioplasty is significantly better than intensive drug treatment for patients who have had a heart attack and still have partially blocked arteries that impair blood flow to the heart but do not cause symptoms, Swiss researchers reported Wednesday.

Reopening the arteries with angioplasty reduced the risk of death or hospitalization by two-thirds over the 10-year follow-up period, the team reported in the Journal of the American Medical Association.

Cardiologists always have suspected that angioplasty was better for such patients, said Dr. John Warner of the University of Texas Southwestern Medical Center. “But the big surprise here is that the number of cardiac deaths decreased significantly. That’s something that is unexpected,” said Warner, who was not involved in the study.