CONGENITAL HEART DISORDER: AORTIC STENOSIS by SHEENA PATEL

Eight out of every 1000 newborns arrive with mild to severe congenital heart defects. These defects are abnormalities in the heart’s structure that are present at birth, which develops during the earlier weeks of pregnancy. Some are related to genetic disorders such as Down syndrome, but the cause of most congenital disorders is unknown. These disorders cannot be prevented, but several treatment options are available. There are several commonly known heart defects such as atrial septal defects (ASD), Atrioventricular Canal Defect, Hypoplastic Left Heart Syndrome, Coarctation of the Aorta (COA), Patent Ductus Arteriosus (PDA), etc., but our main focus is going to be on Aortic Valve Stenosis (Baffa 2008).


To understand more about the congenital disorders and their functionality, it’s helpful to get an overview of a healthy heart and its relationship with the lungs and blood vessels. The heart is the central pump of our body’s circulatory system and consists of four chambers, the left atrium and left ventricle ventricle and the right atrium and right ventricle. The heart also has four valves, which direct the flow of blood through the heart and into the body. The left atrium receives oxygenated blood from the lungs, and empties it into the left ventricle through the bicuspid, also known as the mitral valve. The left ventricle then pumps oxygen rich blood through the aortic bicuspid valve, into the aorta. The aorta is the largest artery in the body. Blood then flows from the aorta into the branches of many small arteries providing the body’s organs and tissues with the oxygen and nutrients they need. After delivering oxygen to the tissues, the now deoxygenated blood returns to the heart through veins. This blood then enters the right atrium of the heart and travels across the tricuspid valve into the right ventricle. The right ventricle then pumps deoxygenated blood through the pulmonary valves into the lungs. The oxygen rich blood, then returns to the left atrium and enters the left ventricle, where it is pumped out to the body once again. This is how blood travels through the heart and body in a normal functioning heart. However, abnormalities in the structures of the heart, such as congenital heart defects can hinder its ability to function properly (Baffa 2008).

One of the more common types of congenital heart disorder is the aortic valve stenosis or aortic stenosis. This condition is present at birth and occurs in about 2% of the population. In people that have this condition, the heart’s aortic valve narrows, preventing the valve from either opening fully or becoming leaky, also known as regurgitation. This narrowing obstructs blood flow from the heart into the aorta and onward to the rest of the body. This obstruction then requires the heart to work harder to pump blood. Overtime, the extra work limits the amount of blood the heart can pump and can weaken the heart muscle, leading to symptoms such as fatigue and dizziness (Mayo 2011). Aortic valve stenosis ranges from mild to severe. During the early stages this condition may not produce any warning signs right away, making it difficult to detect. As the narrowing of the valve develops and becomes more severe symptoms include chest tightness or pain, also known as angina, feeling faint or fainting with exertion. Shortness of breath, fatigue at times of increased activity, heart palpitations and heart murmur (Mayo 2011). A heart murmur is an abnormal heart sound produced in addition to the normal “lub dub” sound. A heart murmur results from the turbulent blood flow through the narrowed valve. This murmur can be heard with a stethoscope during a routine physical performed by a doctor (Mayo 2011).

During a routine physical, if a heart murmur is discovered several tests are taken, and a cardiologist is expected to get the results and gauge the seriousness of the problem. Tests such as an Electrocardiogram (ECG), Chest X-ray, Echocardiogram and Cardiac Catheterization are used to determine how narrow or tight the aortic valve may be. Usually once diagnosed with aortic valve stenosis regular checkups are required to monitor the valve so that surgery can be done at the appropriate time (Mayo 2011).

Symptoms of aortic valve stenosis can sometimes be alleviated with medications, although surgery to repair or replace the valve and opening up the passageway, is the only long term option to treat this condition. Medications that help lower blood pressure or cholesterol may prevent or slow the development of aortic stenosis, but no medications can reverse this. A less invasive procedure known as Balloon Valvuloplasty is sometimes performed in infants and children to relieve aortic valve stenosis and its symptoms. This procedure uses a soft, thin catheter tipped with a balloon that is inserted through a blood vessel in the arm or groin and into the narrowed aortic valve. Once in position, the balloon is inflated so it can push open the aortic valve and stretch the valve opening, thus improving blood flow. The balloon is then deflated and the catheter with the balloon is guided back out of the body. This procedure may work for children; however in adults it isn’t usually successful.

A more complex operation known as Ross procedure is the primary surgical treatment for aortic valve stenosis. The Ross Procedure is also called Switch Procedure and it is named after Dr. Donald Ross, a cardiac surgeon from the United Kingdom (Pettersson 2009). He was the first to propose this procedure in the year 1962, and performed it first in 1967. During this complex procedure the patient’s own pulmonary valve replaces the diseased aortic valve. A homograft, then takes the place of the original site of the pulmonary valve (Weitzel 2009). A donated pulmonary or aortic valve from a human heart, which is preserved, treated with antibiotics and stored under sterile conditions, is known as a homograft. The surgery involves replacing two major heart valves, resulting in the Ross procedure being considered a long and difficult surgery. It begins with the pulmonary valve being taken out and transplanted into the aortic high pressure system as the new aortic bicuspid valve. (Pettersson 2011). Then the homograft, a tissue valve obtained from a pig, cow, or human deceased donor, is used to replace the pulmonic valve (Mayo 2011). Although the Ross procedure is very involved and risky its benefits weigh out the risks. First of all, since a homograft is a tissue valve it is very similar to the native valves of the body and therefore is well tolerated? In addition, people that have their valves replaced with a homograft versus a mechanical valve don’t have to worry about life long medications, such as anti-coagulants, or therapy. Anti-coagulants include Coumadin or its generic Warfarin that is necessary to prevent blood clotting that may occur if a mechanical valve is present (Pettersson 2011).

Aortic valve stenosis, is a very serious condition, because it can weaken the heart. When the valve is narrowed, the left ventricle has to work harder to pump enough blood into the aorta and moving on to the rest of the body. This causes the left ventricle to thicken and damage. At first, these adaptations help the left ventricle pump blood with more force, but eventually these changes weaken the left ventricle and eventually the heart itself. When left undiagnosed aortic valve stenosis can lead to life-threatening heart problems, such as chest pain also known as angina, fainting, heart failure, irregular heart rhythms also known as arrhythmias and cardiac arrest (Mayo 2011). There are however, many treatment options available for a person with congenital heart defects. Most of these defects can be treated successfully, so the sooner a person gets medical help, the better chances they have of making a full recovery and leading a normal life (Baffa 2008).

 

WORKS CITED PAGE

Baffa, Gina. Congenital Heart Defects. Kids Health.org, June 2008. Web. 16 November 2011.
Mayo Clinic Staff. Aortic Valve Stenosis. Mayoclinic.com, 22 September 2011.
Web. 16 November 2011.
Pettersson, Gosta. Aortic Valve Surgery in the Young Adult Patient. Cleveland
Clinic, 2011. Web. 16 November 2011.
Weitzel, Nathaen. Using Real Time Three- Dimensional Transesophageal
echocardiography during Ross Procedure in the Operating Room. Wiley Periodicals, Inc. 26 (2009): 1278-1280. Print.