Our heart requires a steady flow of blood without interruption to keep us alive. Two large blood vessels known as the left and right coronary arteries supply the blood to the heart, but the accumulation of fatty deposits known as plaques can cause these arteries to constrict and stiffen over time. Medical professionals call this process “Atherosclerosis”. Those who have atherosclerosis of the coronary arteries are diagnosed with coronary Artery (Blockages) disease. Coronary artery bypass grafting (CABG), a form of revascularization surgery, is done to increase cardiac blood flow to patients with severe coronary artery disease. Revascularization restores the blood flow to the carrying myocardium.

CABG surgery is a significant surgical procedure in which harvested venous or arterial tubes are used to bypass atheromatous obstructions in a patient's coronary arteries. By restoring blood flow, the bypass helps to alleviate symptoms and restore function and viability to the normal state. CABG is the most frequently done major heart surgery here in India, with more than 60,000 operations performed successfully every year. 

What is CABG Surgery?

With the use of coronary artery bypass grafting (CABG) surgery, blood flow is restored to parts of your heart that aren't receiving enough blood and enough oxygen. This procedure can help your heart work better and make you healthier, especially if you recently had a heart attack or are at a higher risk of having one soon. In a coronary artery bypass grafting, a blood vessel from another location of the body, typically the arm, leg, or chest, is attached to the coronary artery below the blockage or the restricted section to restore normal blood flow.

Medical professionals call this new blood vessel “graft”. The severity of your coronary heart disease and the number of constricted coronary blood arteries will determine how many grafts you require. A coronary artery bypass graft is performed under general anaesthesia, and typically, it takes three to six hours.

The Candidates of a Coronary Artery Bypass Grafting 

Only those with severe coronary artery disease (CAD) that might result in a heart attack are candidates for coronary artery bypass grafting (CABG), especially if other therapies, such as medication or lifestyle modifications, have failed. There are international guidelines  and indications for CABG. Patients are selected on the basis of those guidelines. Your doctor could also suggest CABG if you have significant blockages in the big coronary arteries that provide blood to a significant portion of the heart muscle, particularly if your heart's pumping activity has already been compromised! 

The percentage and location of coronary artery blockages, the intensity of CAD symptoms, your quality of life, how well you respond to various therapies, and any additional health issues you may be experiencing, all of these factors will be considered before the surgery is performed. Remember, CABG may occasionally be carried out in an emergency, such as when a heart attack occurs and the patient needs immediate life-saving treatment.

The primary substitute for a coronary artery bypass graft is coronary angioplasty, and many people are confused about the differences between CABG vs. angioplasty. The thing is, if several coronary arteries have constricted and become clogged, or if the anatomy of the blood vessels is not suitable for stenting, a coronary angioplasty most likely will not be advised by your surgeon. It also depends upon the co-morbid conditions in the patient(DM, HTN, Low EF).

Coronary Artery Bypass Grafting Procedure

Coronary artery bypass grafting is performed by cardiovascular surgeons and a group of other healthcare professionals assist with your treatment.

• The anaesthesist gives you a mild sedative to keep you calm and puts an IV into your forearm before taking you to the operating room. 
• In the operating theatre, you will be put under general anaesthesia.  
• A breathing tube is inserted into your mouth, and this tube connects to a ventilator, a breathing apparatus.  
• A heart-lung machine maintains blood and oxygen flow throughout your body while you undergo surgery during an on-pump coronary bypass.

Typically, Coronary artery bypass grafting takes three to six hours, but the number of blocked arteries determines how long the operation takes.

A surgeon makes a lengthy incision along the breastbone in the middle of the chest, and to reveal the heart, the surgeon opens the rib cage. Following the opening of the chest, medication is used to momentarily halt the heart, and then the switch to the heart-lung machine is done. A portion of a healthy blood artery called a graft, is cut out by the surgeon, usually from the lower leg or inside the chest wall, and then the graft's ends are attached by the surgeon beneath the clogged heart artery. As a result, a new blood vessel is formed to bypass the obstruction, but in some cases, many grafts may be used if necessary.  

CABG has Transformed Heart Surgery with the Latest Techniques 

1. Off-pump Coronary Artery Bypass Surgery (OPCAB)

Off-pump coronary artery bypass surgery (OPCAB) is a modification of the standard operation and is now being performed by many surgeons. In the traditional “on-pump surgery”, a heart-lung bypass machine is used to pump blood and oxygen throughout your body while the heart is momentarily halted, but this heart-lung bypass machine is not used during OPCAB. Instead, your heart continues to pump while the new blood vascular grafts are implanted by the surgeons. 

The National Institute for Health and Care Excellence states that this operation process is just as effective as “on-pump surgery”, but more importantly, OPCAB comes with extra advantages. Compared to the traditional technique, it frequently takes less time to complete, and this procedure also lessens the likelihood that you will bleed heavily during the surgery. Following surgery, you would have a lower chance of experiencing some severe side effects, such as a stroke, and as a result, your hospital stay for observation will be shorter.

OPCAB's primary drawback is that it requires more surgical expertise because the grafted veins must be properly attached while the heart is beating without the help of a machine. This indicates that if many blood vessels need to be grafted, the process could be too challenging to complete. 

2. Totally Endoscopic Robotically Assisted Coronary Artery Bypass (TECAB) Grafting

Totally endoscopic robotically assisted coronary artery bypass (TECAB) grafting is a more recent method in CABG surgery, and the main draw is that it is a keyhole technique for minimally invasive surgery. The surgeon makes many tiny incisions between your ribs and deflates your lungs during a TECAB grafting surgery, and then the operation is performed using robotic arms under the surgeon's direction. 

The robotic arms are equipped with an endoscope, which allows the surgeon to look inside your body and watch the surgical outcomes on a screen! TECAB grafting can be performed off-pump or with a heart-lung bypass equipment depending on the surgeon’s assessment of your condition. This kind of surgery has a quicker CABG recovery period, less scarring, and a decreased risk of wound infection, and that’s why this process is gaining popularity among medical professionals! 

3. Endoscopic Saphenous Vein Harvesting (ESVH)

With endoscopic saphenous vein harvesting (ESVH), the veins in your legs can be removed less invasively to be used as CABG heart surgery grafts. It is called a keyhole surgery because the surgeon makes several little incisions close to your knee instead of a big one in your leg, and after the cut, an endoscope, a specialized tool, will be placed into the cut. The surgeon can find your saphenous vein using the endoscope, and a portion of the vein will be removed with surgical tools to be used as a graft for the CABG surgery. 

Advantages and Possible Complications of Coronary Artery Bypass Grafting 

Advantages  | Possible Complication 
CABG is an established medical procedure with a long history of success   | Temporary problem with irregular heart rhythms (arrhythmias)
Best for the treatment of multiple blockages or blockages in certain arteries | Possibility of post-surgery bleeding if the patient was on blood-thinning medication 
Has a lower risk for follow-up procedures | Chance of infection 

Final Remarks 

Coronary artery bypass grafting has significantly altered the landscape of critical heart surgeries with the use of modern techniques and innovations! The chance of success is high with the use of CABG, and the post-surgery complications are also much lower than traditional surgeries. However, it's crucial to speak with your healthcare provider before you undergo any major surgery, and in the case of heart surgeries, you must discuss with your surgeon about the best option for your condition.