Bypass surgery or stents? How the choice is made when several heart arteries are narrowed

The two treatments, in plain terms

In a coronary angioplasty, a thin tube is passed from an artery in the wrist or groin to the heart. A small balloon widens each narrowing and a mesh tube, the stent, holds it open. It is done under local anaesthetic, and people treated for angina usually go home the same day or the next [7][9].

Bypass surgery (coronary artery bypass grafting, or CABG) is an operation under general anaesthetic. The surgeon takes healthy blood vessels from the chest, leg or arm and attaches them so that blood flows around the narrowed sections [6][8]. Most people spend about a week in hospital and are back to most normal activities after around six weeks; full recovery usually takes two to three months [6][8].

Medication comes first for most people

For stable angina, tablets and treatment of risk factors come first, and a procedure is usually considered when symptoms are not controlled despite good medication [1][2]. Our article on whether you need a stent explains what the large trials found about this.

There is an important exception. When the narrowings involve the left main stem, the short artery that feeds most of the heart muscle, or all three main arteries, a procedure may be recommended to protect the heart in the long term, even when symptoms are well controlled [1][2].

What the large trials found

The SYNTAX trial randomly assigned 1,800 people with narrowing in all three main arteries or in the left main stem to stents or surgery. At one year, the combined rate of death, stroke, heart attack or a repeat procedure was higher with stents, mainly because more people needed a further procedure. Stroke was more common after surgery [3]. The trial also gave its name to the SYNTAX score, which grades how complex the narrowings are [3][5].

The FREEDOM trial studied people with diabetes and narrowing in more than one artery. Over five years, surgery led to fewer deaths and fewer heart attacks than stents, although strokes were more frequent after surgery [4].

In 2018 The Lancet published a combined analysis of 11 trials and more than 11,500 patients. For narrowing in several arteries, survival at five years was better after surgery, particularly in people with diabetes or more complex disease. In people without diabetes there was no clear difference, and for narrowing of the left main stem survival was similar with either treatment [5].

What tips the balance

Taking the guidelines and the trials together, these are the main things weighed [1][2][5]:

• How complex the narrowings are — the more complex the pattern, the more the evidence favours surgery [1][5].
• Diabetes — for people with diabetes and narrowing in several arteries, guidelines recommend surgery over stents [1][4].
• Whether stents could treat the narrowings as completely as surgery — when they can, and the disease is less complex, stents are a recommended alternative [1][2].
• Your general health — other medical conditions, frailty and how well you would be likely to recover from an operation [1][2].
• What matters to you — a longer recovery now, against a lower chance of needing another procedure later [2][3].

Who makes the decision

UK and European guidance both say that when either treatment could be suitable, the case should be discussed by a team that includes cardiac surgeons and interventional cardiologists [1][2]. The 2024 European guideline adds that, in that situation, stents should not be placed straight away during the diagnostic angiogram, so that the discussion can happen first [1]. You should be given balanced information on the benefits and risks of each option, including staying on medication alone [1][2].

Our article on the Heart Team explains how this works. At WellHeart London, a cardiac surgeon, an interventional cardiologist and a consultant cardiac radiologist assess the case and agree the recommendation together — including whether a procedure is needed at all.

What to ask

These questions are worth taking to the appointment:

• How many arteries are narrowed, and how complex is the pattern?
• Could stents treat all of it as completely as surgery would?
• Does diabetes, or anything else in my health, change the advice?
• Have a surgeon and an interventional cardiologist looked at my angiogram together?