Definition and Overview
A valve replacement, as the term suggests, is a surgical procedure that involves replacing one or more of the valves of the heart to treat diseases including stenosis and regurgitation.
The heart has four different valves, which are called (1) tricuspid, which is found between the right atrium and the right ventricle, (2) mitral, which connects the left ventricle to the left atrium, (3) pulmonary, which helps the blood flow from the right ventricle to the lung, and (4) aortic, which delivers oxygenated blood from the heart to other blood vessels of the body. Their job can be classified into two: open themselves to allow blood to pass through the empty the chamber and close at the right time to avoid leaking and prevent the blood from flowing back.
In cases wherein the valves become diseased, doctors can choose to prescribe medications and lifestyle changes, repair the affected valves, or replace them. The last option is only considered when all the other choices have failed to correct the condition and if its benefits significantly outweigh the risks and complications.
When the valves are replaced, mechanical and biological materials are considered, but the choice always depends on the durability, performance, medication requirements, and risks and complications. In the end, the ultimate goal is to restore the patient’s health and vitality and improve the quality of life.
Who Should Undergo and Expected Results
A valve replacement surgery is performed when conditions that affect any of the valves are considered severe or cannot be corrected using other non-invasive or minimally invasive methods. These conditions include:
Stenosis - This refers to the constriction or narrowing of the valves increasing the risk of blood flow obstruction. This condition can be caused by a congenital defect such as a bicuspid valve (two flaps of the valve are fused together), the buildup of calcium deposits, infections, rheumatic fever, and the deterioration of the valve due to age.
Regurgitation – This means that the valves are leaking the blood in more than one direction or the blood is flowing back to its previous chamber. This can be due a heart defect or an infection.
Infective endocarditis (IE) – This refers to an acute infection of the lining of the heart due to bacteria that have invaded the bloodstream and traveled to the heart, affecting the valves or the blood vessels.
Valve replacement is rarely performed on people who have mitral valve prolapse. Rather, this condition is treated with medications such as beta blockers or the valve is repaired. In many cases, the condition is left alone since it doesn’t pose a threat to the person’s health or cause any serious signs and symptoms. In the majority of cases, surgeons opt for less invasive treatments like medications and valve repair before considering replacing the damaged or diseased valve.
If a person with a serious heart valve disease does not undergo valve replacement procedure for any reason, his lifespan can be reduced by up to 25% within the next five years after diagnosis.
How Does the Procedure Work?
There are different surgical options for valve replacement, and the surgeon will choose based on several factors including the overall health of the patient, age, desired result, the new valve’s durability, and the need for medications after.
Two of the most popular methods are called Ross, or pulmonary autograft, and transcatheter aortic valve replacement or implantation (TAVR/TAVI).
In Ross procedure, the problematic aortic valve is replaced by an autograft material. Since it’s derived from the patient’s body, the risk of rejection and complications is significantly reduced.
Meanwhile, the TAVR/TAVI technique is minimally invasive since it requires only small incisions in the chest or femoral artery, after which a catheter is threaded into the damaged valve so the new one can be wedged, creating a better path for the blood to flow.
In many cases, however, the standard valve replacement surgery that involves the opening of the chest (sternotomy) is still performed unless the patient has an underlying condition that can affect the procedure or if the procedure is deemed to significantly reduced the patient’s lifespan, in which case, TAVR/TAVI is considered. Patients may also elect to undergo other less invasive procedures such as robot assisted (where robotic arms are controlled by the surgeons) or endoscopic (where a tube with a camera is inserted in one of the small incisions to see the diseased valve in real time and use the other incisions to operate with microsurgical instruments).
During the valve replacement surgery, the patient is administered with general anaesthesia and is connected to a machine that monitors the heart's performance. A heart-lung machine is also used if the procedure requires the heart to be stopped temporarily.
Possible Risks and Complications
Blood clots and embolisms are not entirely uncommon with people who have undergone valve replacement using a mechanical valve, so they are usually provided with blood thinners before and after surgery. Their long-term response to these medications is also monitored. A valve replacement also doesn’t guarantee that the condition won’t recur, although that’s less likely with individuals who have a mechanical valve since it’s the most durable.
Common surgical risks and complications can also be experienced regardless if the procedure is invasive or minimally invasive. These include scarring on the incision site and certain parts of the heart, damage to the heart’s muscle and tissue, infection, bleeding, cardiac arrest, pain, and breathing difficulties. Minimally invasive techniques, however, have lesser risks due to faster recovery time, less exposure of unaffected cardiac muscles, and smaller incisions.
Fullerton DA, Harken AH. Acquired heart disease: valvular. In: Townsend CM Jr., Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 19th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 61.
Otto CM, Bonow RO. Valvular heart disease. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 66.