Anatomy:

Our heart is a muscular pump approximately the size of a clenched fist in an adult, and its main function is to deliver blood to all parts of the body. The heart has four chambers, two in the upper section, which receive blood from the veins and are called atria, and two in the lower section, which are called ventricles.

The ventricles pump blood through the arteries to the rest of the body. To ensure blood flows in an orderly and timed manner, valves are present at the entry and exit of the ventricles. Physiologically, the heart is divided into the right heart and the left heart. The right heart receives deoxygenated blood (impure blood) returning from all parts of the body into the right atrium. Then, the blood passes through the tricuspid valve (between the right atrium and the right ventricle) into the right ventricle.

When the right ventricle contracts, the blood passes through the pulmonary valve (located between the right ventricle and the pulmonary artery) and enters the lungs to exchange gases and receive oxygen. The oxygenated (pure) blood then returns through the pulmonary veins into the left atrium, passes through the mitral valve (between the left atrium and left ventricle), and enters the left ventricle. When the left ventricle contracts, it pumps blood to the entire body. This process repeats regularly and continuously about 60–80 times per minute throughout life.

Mechanism of Valvular Heart Diseases

Normally, each of the four heart valves functions as a one-way valve, allowing blood to flow in only one direction. The main components of the valves are leaflets, thin but strong tissues that open like a door to allow blood to flow during contraction and close tightly afterward to prevent backflow.

Certain diseases cause the valve leaflets not to close properly after blood passes through, resulting in some blood leaking backward — this is called valvular regurgitation (insufficiency). Conversely, some diseases cause the valve opening to narrow or not open completely, creating resistance to blood flow and reducing the volume passing through — this is called valvular stenosis.

To appreciate the precision of creation, note that each of the four heart valves opens and closes more than 100,000 times a day without obstructing blood flow or allowing backflow.

Types of Valvular Heart Diseases

Valvular diseases generally fall into two categories — stenosis and regurgitation — caused by various underlying conditions:

A) Rheumatic Heart Disease

The most common cause of valvular heart disease in our country and many developing nations is rheumatic heart disease. This chronic condition thickens, stiffens, and deforms the valve leaflets, leading to mitral stenosis, aortic stenosis, and occasionally tricuspid or pulmonary stenosis. Often, regurgitation accompanies the stenosis.

B) Degenerative (Dystrophic) Diseases

In these conditions, valve leaflets become thin, weak, and floppy, causing valve dilation and usually leading to regurgitation. In elderly patients, it may also cause aortic stenosis.

C) Infectious Diseases

Sometimes, during bacterial infections, the heart valves become directly infected (endocarditis), leading to valve destruction and acute or chronic valve insufficiency.

D) Congenital Diseases

All heart valves may be congenitally narrowed or insufficient. Valve involvement may also occur as part of a complex congenital heart defect.

E) Trauma

Direct or indirect chest trauma can cause tears in valve structures, leading to insufficiency.

Symptoms of Valvular Heart Diseases

Although symptoms vary depending on which valve is affected, the most common symptom is shortness of breath during physical activity — such as climbing stairs, running, or walking uphill. If this occurs, especially if it is new or appears with lighter activities than before, it should be reported to a physician.

Other common symptoms include fatigue, weakness, chest pain, leg swelling, palpitations, and difficulty breathing while lying flat.

Prevention of Valvular Heart Diseases

While it may seem difficult to prevent these diseases, many causes can be indirectly avoided. For congenital cases, parents can help prevent them by avoiding consanguineous marriage, seeking genetic counseling, abstaining from alcohol and tobacco during pregnancy, and avoiding self-medication.

Surgery and Operating Room Procedures

After being transferred to the operating room, the anesthesiology team prepares the patient by attaching cardiac monitoring electrodes and inserting intravenous lines for anesthesia and fluids. The patient feels minor pain only at this stage. Next, an arterial line is placed to continuously monitor blood pressure.

A mask is then placed on the patient’s mouth and nose to deliver oxygen and anesthetic gases. The anesthesiologist then fully induces anesthesia, and the surgical team begins the operation. In coronary artery bypass graft (CABG) surgery, a heart-lung machine temporarily replaces the functions of the heart and lungs, allowing the surgeon to stop the heart and sew bypass grafts.

Another technique, known as off-pump CABG, performs grafting while the heart is still beating using special stabilizing tools. The number of grafts and duration (typically 3–4 hours) depend on the extent of disease. After surgery, patients are transferred to the ICU while still under mild anesthesia and connected to a ventilator.

When anesthesia wears off, the breathing tube prevents speech, which is normal. Patients should remain calm and breathe normally; the tube is removed once spontaneous breathing is sufficient.

They may feel the need to urinate due to a urinary catheter — again, no cause for concern. In the ICU, multiple monitors and tubes are routine for all patients, not a sign of complications. Chest tubes are placed to drain blood and prevent accumulation in the chest cavity.

After tube removal and recovery, patients gradually resume drinking, eating, and breathing exercises to restore lung function.

Postoperative Care

After ICU, patients usually no longer need IV medications except for heparin (if prescribed). Temporary pacing wires placed during surgery are removed within 4–5 days without pain. Wound dressings are usually discontinued after the third day, and echocardiography is performed to assess heart function before discharge.

Once all tubes are removed, patients can shower, walk, and perform light exercises with rehabilitation staff. Typically, after 3–5 days in recovery, patients are discharged if no complications occur.

After discharge, they must take prescribed cardiac medications, especially aspirin, maintain a low-fat, low-salt diet, avoid polluted and smoky environments, and walk regularly. They should see their doctor 3–4 weeks later for reevaluation.

If symptoms such as fever, severe fatigue, excessive wound pain, leg swelling, shortness of breath, or wound discharge appear, they should consult their doctor immediately.

Common Questions About Coronary Artery Disease

1. Are coronary arteries removed and replaced during bypass surgery?

No. The blocked section is simply bypassed using another vessel to reroute blood from the aorta to the healthy segment of the coronary artery.

2. What are the advantages of endoscopic vein harvesting?

It uses smaller incisions, improving cosmetic outcomes and reducing pain and infection risk, though it requires specialized tools and skill.

3. Are arterial grafts better than venous ones?

Arterial grafts, particularly the internal mammary artery, have superior long-term patency rates (over 90% after 10 years). Radial artery grafts from the forearm are also effective, especially in younger patients. The choice, however, should be made by the surgeon based on individual factors.