Yes, inserting a stent to open a blockage that’s causing a heart attack can be lifesaving for a patient having a heart attack—but there is growing controversy about how much it can help if used pre-emptively.

Stenting, an invasive and potentially risky procedure, has become standard practice for too many heart patients—over 1.8 million a year in the US, even though multiple studies have questioned its effectiveness. In the latest trial of over 5,000 participants, researchers found that placing stents in arteries of patients with stable and mild coronary artery disease as a pre-emptive measure doesn’t prevent heart attacks or extend life for most patients and is no more effective than medication and lifestyle changes. Worse, risks include blood clots, strokes, heart attack or infection.

Why doesn’t stenting help? Heart disease is a disease of the endothelium—the tissue that lines blood vessels and organs—and the stent fixes just one damaged spot. For a system-wide problem, you need a whole-body approach that includes managing blood pressure, cholesterol, blood sugar and your weight.

If your doctor suggests a stent, ask about both the risks and benefits for your particular circumstances. For example, a stent may be the answer when symptoms like the pain of angina make it too challenging to exercise—a stent might be necessary to enable you to adopt a healthier lifestyle.

If you already have a stent, remember that it didn’t fix your heart disease. It only added support. Best advice: Exercise and eat a primarily plant-based diet to avoid developing more blockages.