Heart Bypass Surgery (CABG): A Surgeon's Step-by-Step Guide

If you've just been told you need a heart bypass, you probably have more questions than answers right now. Let me explain it the way I do when a patient sits across from me in my clinic.

Coronary Artery Bypass Grafting — CABG, or simply “bypass” — does not clear a blocked artery from the inside. Instead, I take a healthy blood vessel from your own body and build a new road for blood to travel around the blockage and reach the heart muscle beyond it. For advanced coronary artery disease, this is still the most complete and durable fix we have. After fifteen years and more than 5,000 surgical cases, it remains the surgery I trust most for the right patient.

In this guide I'll walk you through why bypass is done, how it actually works, the techniques we use today, what happens on the day of surgery, and what recovery really looks like — without the jargon.

Your heart is a muscle, and like any muscle it needs its own steady blood supply. That job belongs to the coronary arteries. When plaque narrows or blocks them, the heart begins to starve — and that starvation is what you feel as chest pain, or angina. Left alone, it can tip into a heart attack, or worse, a cardiac arrest.

Bypass fixes this at the root. I carry blood past the blockage to the muscle waiting beyond it. Relieve the starvation, and the chest pain and breathlessness ease — and, just as importantly to me, the risk of a future heart attack drops.

The fear I hear most before surgery:

"The most common fear before bypass surgery is death — patients ask me, ‘Will I survive this operation?' I tell them the survival rate is around 99%; with the advances and skills we've gained over the years, the risk is less than 1%. Their second fear is that they'll be stuck at home afterwards, of no use. That's simply not true — after recovery, my patients are active. They work, they exercise, they live fully, guided by our advice."

— Dr. Amjad Shaikh

Not every blockage lands on my operating table. Many are managed perfectly well with stents or medication. Bypass earns its place when the disease is widespread, or when it sits in the arteries that matter most. In practice, I recommend it when there is:

• More than two blockages, or all the major arteries affected — what we call triple-vessel disease
• A blockage in the left main artery, which feeds the largest share of the heart
• Multiple blockages in a younger patient, or a diabetic patient — where surgery protects the heart better over time than stenting does

The map I'm working from

It helps to picture the heart's arteries. Two main vessels supply it — the left and the right. The left main quickly splits into the left anterior descending artery (the LAD, running down the front of the heart) and the circumflex (which curves around the side). The LAD sends off diagonal branches; the circumflex sends off obtuse marginal branches; and the right coronary artery covers the rest.

A blockage can sit anywhere along this map. When all three main arteries are badly narrowed — triple-vessel disease — that's the classic situation where bypass gives the best long-term result.

Watch: a real operation

LIMA–RIMA beating-heart bypass with four graftsi.

Why the choice of graft matters so much

A “graft” is simply the new vessel I use to reroute the blood. There are two families to choose from, and picking the right one is one of the most important decisions I make in the whole operation.

Arterial grafts are the ones I reach for first, because they stay open the longest — often around 20 to 25 years. The workhorses here are the LIMA (Left Internal Mammary Artery) and RIMA (Right Internal Mammary Artery) from inside the chest wall, and the radial artery from the forearm. There's something elegant about these vessels: they naturally resist the very plaque that blocks everything else.

Vein grafts — usually the saphenous vein from the leg — are dependable and versatile, but I use them selectively. They just don't last quite as long, typically around 10 to 15 years.

Supporting evidence: Arterial grafts, including the internal mammary artery, showed patency of up to ~96% at 15 years in a study of over 2,000 conduits (Tatoulis et al., Ann Thorac Surg 2004); the landmark Loop et al. study (NEJM 1986) showed mammary-artery grafts improve long-term survival — Tatoulis 2004 (Ann Thorac Surg)

Why I prefer off-pump surgery and arterial grafts:

"Off-pump surgery avoids the heart-lung machine, and with it the risks of stroke, infection, and multiple blood transfusions — it's quicker, less expensive, and done on a beating heart. As for grafts: a vein lasts approx. 10 to 15 years, but the LIMA and RIMA arteries work for approx. 20 to 25 years, with studies showing around 95% still open at approx. 25 years. That's why total arterial grafting with LIMA-RIMA is my preferred approach — though how long any graft lasts also depends on the patient's lifestyle after surgery: controlling diabetes, blood pressure, and cholesterol, staying active, and avoiding tobacco."

— Dr. Amjad Shaikh

One graft, or five?

It depends entirely on how many vessels are blocked. A single blockage at the start of the LAD may need just one graft. When several arteries are involved, I do all the grafts in the same operation — four or five in one sitting is common when the disease is widespread.

I'll be honest about something I see almost every week in my practice. Diabetes is common among my patients here, and it rarely blocks just one artery politely — it tends to cause multiple, diffuse blockages throughout the coronary tree. For these patients, the evidence and my own experience point the same way: bypass usually protects the heart better than stenting.

Supporting evidence: In the FREEDOM trial and its long-term follow-on study (Farkouh et al., J Am Coll Cardiol 2019), people with diabetes and multivessel disease had significantly better long-term survival with bypass surgery than with drug-eluting stents — FREEDOM Follow-On 2019 (JACC)

How diabetes shapes my approach:

"Diabetes is one of the most important causes of coronary disease, and it tends to cause multiple, diffuse blockages. I control the patient's diabetes precisely before and after surgery — keeping HbA1c around 7 — because good control slows the build-up of new blockages and cholesterol deposits. In a diabetic with multiple blockages, I prefer bypass with multiple grafts; putting in multiple stents is not a good idea."

— Dr. Amjad Shaikh

Patients often arrive expecting me to argue for surgery. I don't. Bypass and angioplasty aren't rivals — they're two tools for two different problems. A stent is excellent for one or two discrete blockages, and it's often the fastest way to open an artery during a heart attack. But when the disease is spread across three vessels, or sits in the left main, bypass gives more complete and longer-lasting relief. That's the honest distinction I draw for every patient.

On-pump (traditional). A heart-lung machine takes over while the heart is stopped, and I do the bypass on a still heart. It served us well for decades, and still has its place in certain cases.

Off-pump (beating-heart). My preferred approach for most patients. No heart-lung machine — the heart keeps beating while a stabiliser holds steady just the small patch I'm working on. Skipping the machine avoids a whole set of its complications, from stroke to infection.

Supporting evidence: In the large CORONARY trial, including its 5-year results (Lamy et al., NEJM 2016), off-pump surgery reduced bleeding and transfusion needs, with long-term survival similar to on-pump; off-pump outcomes are best in experienced hands — CORONARY 5-year 2016 (NEJM)

Minimally invasive. Here I reach the heart through a small cut on the side of the chest, without dividing the breastbone at all. Recovery is faster and the scar is smaller — though not every set of blockages suits this approach.

Emerging techniques. Robotic-assisted bypass, through keyhole incisions, is an advancing field aiming for even greater precision and quicker recovery as the technology and training mature.

This is not the operation it was when I started. The field keeps moving — more arterial grafts for longer-lasting results, hybrid procedures that pair bypass with a stent, steadily better minimally invasive techniques, and now the early role of robotics.

What's changed in fifteen years:

"In my 15 years, bypass surgery has changed enormously. We moved from on-pump to off-pump, beating-heart surgery. We shifted from using mostly vein grafts to using the LIMA and RIMA arteries, because they last far longer. And instead of opening the chest, we now do minimally invasive, keyhole surgery without cutting the breastbone — each step making recovery faster and safer for patients."

— Dr. Amjad Shaikh

In hospital

Most patients go home in five to six days. Once the drains are out and you're walking comfortably, you're ready. I'll ask you to stay active at home, and to wear a chest support belt for about 45 days while the breastbone knits.

Pain and wounds

Kidney-safe painkillers cover the first week, and the pain usually settles a lot after the first couple of days. Wound problems are uncommon — the main exception is a patient whose diabetes isn't well controlled, where the risk climbs to around 3%. That's exactly why I'm so strict about blood sugar.

Getting back to life

Everyday activities usually resume around 20 days after surgery, and most patients are back at work within a month.

The mistake I see families make most:

"The most common mistake I see is families keeping the patient confined to bed, not letting them walk or talk — thinking they're protecting them. It harms both mind and body. Patients need to know their life will be good after surgery, and they need to stay mobile to rebuild physical strength. I always ask families to encourage movement and follow our advice."

— Dr. Amjad Shaikh

If it was minimally invasive CABG

When I can do the bypass without dividing the breastbone, recovery is noticeably quicker — less pain, a smaller scar, and routine activities back in around 8 days rather than 15 to 20. There's no long cut in the chest either. Not everyone is a candidate; it depends on the pattern of blockages, comorbidities and my assessment.

When to call us

Ring your surgeon promptly if you feel very weak, giddy, or have chest pain coming back during recovery. Don't wait it out.

The section above is the “what”; this table is the “when.” It's a general guide — I tailor it to each patient, and no two people heal at quite the same pace.

Every operation carries some risk, and I'd rather you hear them from me. The usual ones are infection, bleeding, an irregular rhythm (atrial fibrillation), and a small stroke risk. In experienced hands and a well-equipped centre, the chance of a serious complication is low. A minority of patients get some chest-wall discomfort later, in under 2% of cases. And doing the bypass on a beating heart, without the heart-lung machine, sidesteps many of the complications people used to associate with this surgery.

Versus angioplasty. One or two blockages? Often a stent is the answer. But more than three, or left main disease, or a critical blockage right at the start of an artery — that's where bypass is the more durable choice.

Versus medication alone. Medicines have their place — for very elderly patients, those unfit for surgery, or those with serious other illnesses. They ease symptoms, but they don't cure advanced blockages.

Here's the part patients underestimate: the surgery is only half the story. I can build you perfect grafts, but what you do afterwards decides how long they last. A daily 30-minute walk is one of the best things you can do. Go easy on deep-fried food and red meat. If you're diabetic, keep that sugar tight.

The good news is that most of my patients need few medicines afterwards, with a check-up every six months. The strongest protection against new blockages isn't in my hands at that point — it's in yours: staying active, controlling diabetes, and staying away from tobacco completely.