Left Main Coronary Artery Disease: When Bypass Beats a Stent

For left main coronary artery disease, coronary artery bypass grafting (CABG) is generally the better treatment than a stent, and the same holds for complex disease with a high SYNTAX score and for younger patients. Bypass grafts last longer and give a longer disease-free life. Stents remain the right choice for frail, older patients, for acute heart attacks and for stabilising a patient before surgery.

That is how Dr. Biswarup Purkayastha, Consultant – Heart & Lung Transplant and Vascular Surgery, Artemis Hospitals, Gurugram, India, summarised the choice between percutaneous coronary intervention (PCI, angioplasty with a stent) and bypass surgery. His "key home message" is short: left main disease, bypass grafting; younger patient, bypass grafting. This article sets out how he reaches those decisions, the tools he uses to grade complexity, and why he asks referring doctors to request total arterial revascularisation by name. The broader management of coronary artery disease is covered in the complete guide.

Left main coronary artery disease: why bypass is preferred

The left main coronary artery is the short trunk that divides into the left anterior descending artery and the circumflex artery. Together these supply most of the left ventricle, the heart's main pumping chamber, so a blockage in the left main puts a large territory of heart muscle at risk at once.

Dr. Purkayastha's position is that any patient whose angiogram shows left main involvement is a better candidate for bypass grafting than for a coronary stent. Several randomised trials have compared the two in left main disease, including EXCEL and NOBLE, and their results have differed in places. Even so, he regards it as generally accepted that bypass surgery gives these patients a longer period of disease-free survival. Current European and American guidelines recommend CABG for significant left main disease, with PCI as a reasonable alternative mainly where the rest of the coronary anatomy is of low complexity.

He was equally clear that stents still have a role here. PCI is a quick, easy fix with rapid recovery, and patients do reasonably well in the first month. A stent can stabilise a patient whose heart attack is evolving, giving the heart a chance to recover some of its function, before the patient is sent for definitive bypass surgery. But where the aim is durability and a longer life, bypass is, in his words, the operation of choice. For any referral where the angiography report mentions the left main, he asks physicians to be very cautious about which therapy they suggest.

What the long-term trials show

Four randomised trials anchor the debate, and in Dr. Purkayastha's reading the long-term results support bypass surgery for disease-free survival. He cited SYNTAX, NOBLE, PRECOMBAT and EXCEL, noting that SYNTAX and PRECOMBAT have followed patients for about ten years.

At ten years, the clearest difference in these trials is in repeat procedures, which are needed considerably more often after stenting. Differences in survival are smaller and depend on the pattern of disease: they favour surgery most clearly in three-vessel disease and are close to even in left main disease of low complexity. Dr. Purkayastha's separate masterclass covers this evidence in more depth in PCI vs CABG: the evidence.

The SYNTAX score: grading complexity

The SYNTAX score guides the decision where the coronary arteries carry a heavy calcium load or the anatomy is complex. It grades the number, position and complexity of the blockages seen on the angiogram. It is usually calculated by a cardiologist using the free online calculator: the findings are entered into a form, and the score places the patient in one of three bands.

Calculating a SYNTAX score requires an angiogram or a CT coronary angiogram. A EuroSCORE, which estimates the risk of heart surgery from the patient's general health, can be calculated without one.

Multivessel disease: bypass or multiple stents?

In a resource-constrained setting, Dr. Purkayastha considers bypass surgery the option of choice for multivessel disease. Some centres have done very well with multiple stents when several coronary arteries are diseased. His concern is that this is not a widely replicable practice, and that in a resource-constrained setting a consistently good multivessel PCI may not be possible.

How long a bypass lasts compared with a stent

In Dr. Purkayastha's assessment, bypass surgery is a reliable, stable and reproducible operation that gives a disease-free life in excess of ten years, and possibly 15 or 20. A stent, in contrast, is a time-limited stop-gap: newer stents are said to last a lifetime, but in his experience more than ten years is a rarity. This difference in durability is central to his reasoning.

The conclusion follows. A young patient with more than ten years of life ahead should, more often than not, have bypass surgery rather than a stent. Younger patients with minor disease that does not need surgery can be managed with medicines.

When a stent is better than bypass surgery

A stent is the better choice for older and frail patients, during an acute heart attack, and to stabilise a patient before surgery. Dr. Purkayastha sees a clear place for stenting:

• Older and frail patients, and those who do not want, or cannot tolerate, a long hospital stay. For them, PCI is the ideal.
• Acute heart attack. Primary PCI, opening the blocked artery with a stent during the heart attack, has a definite role in acute management.
• Stabilisation. A stent can hold a patient steady for a period before planned surgery.

He drew on a published framework that sets out the factors favouring each treatment:

Factors favouring PCI:

• severe comorbidity
• advanced age, frailty or reduced life expectancy
• restricted mobility
• a SYNTAX score of 22 or below
• anatomy in which bypass surgery would likely leave revascularisation incomplete, because of very poor quality target vessels or no usable grafts (for example, leg disease that rules out taking a vein, or a chest wall abnormality that prevents harvesting the internal mammary artery)

Factors favouring CABG:

• diabetes
• reduced ejection fraction (weak heart pumping)
• left main coronary artery disease
• heavily calcified coronary arteries
• a high SYNTAX score
• disease of the ascending aorta that needs treatment at the same time

His point is that long-term management of left main disease, of younger patients and of complex coronary disease should not be stenting alone. Much of it is better served by bypass grafting.

The frail, older patient

A case from the session shows the other side of the balance. An older diabetic patient on long-term haemodialysis presented with an NSTEMI (a heart attack without ST elevation on the ECG). Dr. Purkayastha's view was that an older diabetic who has just had a heart attack is not the ideal patient to take straight to the operating table. For frail, older patients who need a quick fix, he considers a stent at times a very good way to buy time and get them through. The early management of that case is described in the complete guide.

Total arterial revascularisation: an artery for an artery

Total arterial revascularisation is bypass surgery in which every graft is an artery, and Dr. Purkayastha argues strongly for it. In conventional CABG, surgeons use an artery from inside the chest wall together with veins taken from the leg. In total arterial revascularisation, no veins are taken from the legs; the grafts come from arteries, usually both internal mammary arteries in the chest wall and often the radial artery in the forearm.

His principle: it is always better to replace an artery with an artery. He regards total arterial bypass grafting as probably the most suitable option for any patient undergoing revascularisation for coronary artery disease. It is a routine part of his practice: he performs 60 to 70% of his coronary bypass operations as total arterial revascularisation.

He described a patient he had revascularised with this technique the night before the session. By the next day the patient's heart function had improved, he was off all inotropic medication (drugs that support the heart's pumping), he was walking, and he had no excess chest pain or wound healing problem.

The evidence he cited

Dr. Purkayastha presented a large published series of about 4,000 patients treated between 2011 and 2018, most of whom had PCI. In his summary of that study, mortality with CABG was about half that with stenting (about 13% against 26%), and the rate of strokes and other major adverse cardiac and cerebrovascular events was also roughly halved. His conclusion is that CABG with arterial grafts gives patients with coronary artery disease better long-term survival and far fewer adverse events.

What a bypass operation involves

He walked through the operation itself. The breastbone is divided and held open with a metal retractor so that the surgeon can see the heart. A tissue stabiliser, a device known as the "octopus", holds the area of the heart where a graft is needed still, and the graft is sewn onto the coronary artery beyond the blockage.

What referring doctors should request

Dr. Purkayastha closed his lecture with a specific request. When a general practitioner refers a patient for bypass surgery, the referral note should ask for total arterial revascularisation wherever it is even remotely possible. He framed it in terms of long horizons: in his view, the choice changes the patient's outcome not over years but over the decades to come. He was careful to add that he recommends it not because he is a surgeon, but because the patient deserves it.

Indicative costs for both procedures are on the CABG cost page and the angioplasty with stent cost page. Recognising a heart attack and the first 120 minutes of care are covered in the article on heart attack symptoms and first steps. Questions from the session are on the Live Discussion page, and more on surgical options is on the cardiac surgery hub.