“It is really helpful to have some kind of results to show people,” Dr. Lerner said. “I will predict 100 percent that I will have some patients who say, ‘If you are not going to check the LDL level and you cannot tell me the statin is working, then I am not going to take it.’ ”

Monitoring LDL levels has been an ingrained part of preventing heart attacks for decades.

“The terminology that keeps coming to mind is ‘leap of faith,’ ” Dr. Lerner said. “You have to trust your doctor and the people who did the studies that they are correct that you don’t have to check LDL levels.”

Image Dr. Neil J. Stone, chairman of a committee on cholesterol. Credit... Megan Bearder for The New York Times

Patients and doctors striving for low numbers are now being told that they should regard taking a statin as they might regard taking aspirin to reduce their heart attack risk: a pill a day, with no monitoring required. This advice has left some cardiologists wondering what to do about patients who are at high risk but cannot tolerate statins or refuse to take them.

“Clearly, the focus is to get people on statins,” said Dr. Christie Mitchell Ballantyne, the chief of cardiology and cardiovascular research at Baylor College of Medicine, in Houston. “But if someone has seen four doctors and tried six statins and tells me they can’t take them, what am I going to do? Tell them they are a failure?”

Dr. Ballantyne said he would give such patients a nonstatin drug, despite the guidelines.

Still, some doctors agree that cholesterol targets have been too much of a fixation. Many people, both doctors and patients, have lost sight of the fact that the goal is to reduce the risk of heart disease, not just LDL levels, said Dr. Steven Woloshin, an internist at Dartmouth.

“If you ask patients, ‘Why do you take a statin?’ ” Dr. Woloshin said, “they say ‘to lower my cholesterol level,’ not ‘to lower my cardiovascular risk.’ ”