PCI vs CABG: The Evidence, Heart Attack Care and Prevention

For complex coronary artery disease, the PCI vs CABG evidence favours bypass surgery. In Dr. Biswarup Purkayastha's reading of the SYNTAX, NOBLE, PRECOMBAT and EXCEL trials, bypass surgery brings fewer adverse events at one year, less repeat revascularisation and more durable grafts than stenting, at the cost of a somewhat higher 30-day adverse event rate. Stenting suits frail patients, acute problems and young patients buying time.

Coronary artery disease is the half of the cardiac burden that Dr. Biswarup Purkayastha, Consultant – Heart & Lung Transplant and Vascular Surgery, Artemis Hospitals, Gurugram, India, regards as largely preventable. His positions are pointed: load antiplatelets aggressively when no catheterisation laboratory is available, choose bypass surgery over stenting for complex disease, graft "an artery for an artery", and stop trusting packaged cooking oils and gym culture to protect the heart. The scale of the problem in sub-Saharan Africa, and how symptoms differ in women and diabetics, are covered in the complete guide to heart failure and coronary artery disease in Africa.

Treating a heart attack without a cath lab

Where no catheterisation laboratory (cath lab, the X-ray suite in which blocked arteries are opened and stented) can be reached in time, Dr. Purkayastha's algorithm is to load the patient with antiplatelet drugs and, where it is available, to give a clot-busting thrombolytic.

Antiplatelet loading as the first-line therapy

In many settings, primary percutaneous coronary intervention (PCI) for a heart attack is not available within the next couple of hours. For that situation Dr. Purkayastha presents a deliberately simple algorithm. Whether the patient has an ST-elevation or a non-ST-elevation myocardial infarction, if PCI cannot be performed promptly, the option in hand is medical therapy: load the patient with aspirin plus clopidogrel or another second-line antiplatelet drug. Standard loading doses are 150 to 325 mg of aspirin and 300 to 600 mg of clopidogrel.

The antiplatelet agents he lists as widely available across Africa are:

• Aspirin, the foundation of the algorithm
• Clopidogrel, available as Plavix
• Ticagrelor, available as Brilinta, which he considers an excellent drug for non-ST-elevation myocardial infarction

Thrombolysis where it is available

The second tool is thrombolysis with a tissue plasminogen activator, which he describes as a clot-busting drug for acute myocardial infarction. Fibrinolysis is most effective in the first few hours after symptom onset and is recommended within 12 hours of onset for ST-elevation myocardial infarction when primary PCI cannot be delivered in time. He acknowledges that availability is limited, but in a resource-constrained setting a thrombolytic agent given at the right time can restore very good flow in the blocked vessel, at times achieving TIMI grade 2 or 3 flow (TIMI grades describe blood flow through the treated artery, with grade 3 being normal flow).

The bleeding question

A heavy antiplatelet load carries a real risk of bleeding, and clinicians often ask how to manage it. Dr. Purkayastha's answer is that, in this situation, you accept it. For a patient who cannot receive PCI, antiplatelet loading, with fibrinolysis where it is available, is the best chance of opening the blocked coronary artery and keeping it open. Bleeding can only be controlled in a living patient. If the patient dies of a myocardial infarction for lack of treatment, he asks, whose bleeding is there left to control? His full answer to this question, and to questions on diet and fitness, is in the Live Discussion from the masterclass.

Blood tests for suspected coronary artery disease

Every patient suspected of coronary artery disease, in his practice, should have a defined set of blood tests:

• full blood count
• kidney and liver function
• cholesterol profile
• clotting studies (APTT and INR) if the patient is on anticoagulants
• HbA1c, to gauge long-term blood sugar control
• BNP or NT-proBNP
• high-sensitivity C-reactive protein, to detect underlying inflammation that creates a hotbed for coronary atherosclerosis

PCI vs CABG: how the choice is made

The choice between PCI and CABG turns on how complex the coronary disease is, graded by the SYNTAX score, and on the patient's age and fitness: the more complex the anatomy, the stronger the case for bypass surgery.

Treatment begins with lifestyle change and medication to bring diabetes and cholesterol under control. When a procedure is needed, the choice is between coronary stenting (PCI), in which a narrowed artery is opened with a balloon and held open with a stent, and coronary artery bypass grafting (CABG), in which blood is routed around the blockage through a graft vessel. The cost of angioplasty with a stent and the cost of CABG are set out separately.

How the decision is made

Dr. Purkayastha describes a structured assessment:

1. A careful evaluation of the patient's angina.
2. A coronary angiogram.
3. Where needed, physiological studies such as fractional flow reserve (FFR) or the instantaneous wave-free ratio (iFR), to establish whether a narrowing actually limits blood flow and whether the patient would benefit from intervention.
4. A SYNTAX score, which grades the complexity of the coronary disease as low, intermediate or high. Scores of 22 or below are low, 23 to 32 intermediate, and 33 or above high.

The higher the SYNTAX score, the worse the coronary anatomy, and the more the patient benefits from bypass surgery rather than stenting. A low score, or an acute problem that needs an immediate solution, points towards a stent.

PCI vs CABG: what the trials show

Drawing on the SYNTAX, NOBLE, PRECOMBAT and EXCEL trials, Dr. Purkayastha summarises the evidence as a trade-off over time.

Bypass surgery has fewer adverse events at one year and a lower chance of repeat revascularisation from stent blockage or graft failure. Grafts are more durable and, ultimately, patients gain more quality-adjusted life years. The cost is front-loaded: CABG carries a somewhat higher 30-day adverse event rate, partly because something as minor as a surgical site infection counts as 30-day morbidity. The first two to three weeks may be difficult. In his view, fear of that early period alone is not a good reason to give up on surgery.

Stenting has its own merits. It is a quick procedure, recovery in the first month is almost immediate, and patients go home right away. He sees three clear roles for it:

• an older or frail patient who is not fit enough for surgery or is extremely sick
• a patient with an acute problem that needs an acute solution
• a very young patient who wants to buy time before a definitive operation, with PCI as a bridge to a later, interval CABG

He adds that anaesthesia and open cardiac surgery have evolved to the point where they become safer every year, and in his view very few patients today are genuinely too sick to undergo and recover from them.

PCI and CABG success rates and risks

In Dr. Purkayastha's view, surgical success rates for coronary disease are comparable across the world, upward of 90%. Across units, pathologies and degrees of severity, Dr. Purkayastha expects a 5 to 7% risk of morbidity and mortality after bypass surgery, and a similar figure applies to stenting.

Total arterial CABG: "an artery for an artery"

Total arterial grafting uses only arteries as bypass conduits, and Dr. Purkayastha regards it as the best form of coronary surgery.

The case for arterial conduits

If transplantation is the holy grail of heart failure treatment, Dr. Purkayastha regards total arterial bypass grafting as the epitome of coronary surgery. His preferred configuration uses both the left and right internal mammary arteries, which run down the inside of the chest wall, known as bilateral internal mammary artery (BIMA) grafting.

He points to a study published in the Annals of Thoracic Surgery that compared multi-arterial CABG with PCI in about 850 patients in each arm, treated between 2013 and 2018. Bypass with arterial conduits improved survival and reduced adverse events compared with stenting.

Reading the stent trials critically

Dr. Purkayastha makes a pointed observation about the design of the trials that support stenting. They are non-inferiority trials, not superiority trials. The best they have shown is that PCI is not inferior to CABG. In his assessment, no trial to date has claimed PCI to be better than CABG without being heavily criticised for serious industry involvement. His summary: if a blocked artery is to be bypassed, bypass it with an artery.

Graft quality over surgical technique

He is equally direct about minimally invasive and robotic coronary surgery. His unit offers minimally invasive CABG for the right anatomy. But at international meetings such as the ISMICS meeting, which he describes as the largest gathering for minimally invasive cardiac surgery, senior practitioners, he says, acknowledge that right-sided grafting remains a struggle with either a robotic or a minimally invasive approach, and that some problems are still best addressed with conventional surgery.

For younger patients his priority is unambiguous: the quality of the grafts matters more than the technique of grafting. A robotic CABG using one internal mammary artery plus vein grafts is, in his view, worse than a conventional total arterial CABG. The patient should leave the choice of technique to the surgeon, and should not accept a compromise on graft quality.

Preventing coronary artery disease: diet, cooking oil and fitness

The basics

Prevention starts with healthy eating, stress management, giving up smoking, a reasonable amount of daily walking, keeping weight in check and knowing one's blood numbers more regularly than others do. A first-degree family history of heart disease calls for extra vigilance. Dr. Purkayastha points out that a single habit, such as cycling to and from work, delivers several of these benefits at once: exercise, stress relief and weight control.

The 2-3-4-5 plate

His standard dietary guidance is a plant-based pyramid of 2-3-4-5. Every day, a person should eat:

• 2 or more plant-based legumes
• 3 or more fruits
• 4 or more vegetables
• 5 or more different whole grains

The cooking oil problem

A common objection is that much of the Indian population is vegetarian and broadly follows this pattern, yet cardiac events have risen over the last two to three decades. Dr. Purkayastha's explanation is the cooking medium. The traditional diet moved from mustard oil and other naturally sourced oils to artificial, packaged oils marketed on their omega fatty acid content. Consumers were persuaded that the same oil used to fry fast-food chicken would deliver excellent cardiac health. First it was omega-3, then omega-6, and, he says wryly, the numbers will keep climbing.

His advice is to stop chasing omega numbers. Returning to traditional olive or mustard oil, and giving up clarified butter and modified, omega-loaded packaged cooking oils, would in his estimate eliminate half of the heart disease in the country.

Does being fit mean a healthy heart?

Dr. Purkayastha is sceptical that physical fitness alone signals a healthy heart. A gym will ask a new member for a medical certificate, but not for blood work: not triglycerides, homocysteine or CRP, and not a reliable body fat measurement beyond a handheld gadget. Meanwhile many gym-goers take large quantities of supplements, most of them unapproved and unregulated, from a billion-dollar industry selling jars of powders whose contents nobody really knows.

The focus on building muscle mass overlooks the fact that the heart is also a muscle, and it thickens too. Training-related thickening is usually a benign adaptation known as athlete's heart; hypertrophic cardiomyopathy is a distinct, usually inherited disease that has to be told apart from it, because it is a leading cause of sudden cardiac death in young athletes.

Athletes, arrhythmias and wearables

Well-trained athletes characteristically have a slow resting heart rate, known as athletic bradycardia, which results from cardiac hypertrophy, increased vagal tone and other complex physiology. Medicine has recognised it for a long time. What has changed is detection. With wearables and other monitoring devices, more arrhythmias are being found than ever before. Something as simple as an Apple Watch can detect atrial fibrillation, and people have benefited from it. For athletes and others with dangerous rhythm disorders, the protective role of the ICD is discussed in heart failure surgery: valve repair, LVADs and transplant.