In this series of posts I will help you understand heart valve problems (valvular heart disease). Today's topic is aortic stenosis.
What Is Aortic Valve Stenosis?
The aorta is the large blood vessel carrying blood to your body; stenosis just means ‘stuck’. In other words, aortic stenosis is a ‘stuck valve’.
Understanding The Anatomy of Your Heart
TIP #1: Try to imagine that your heart is a 4 room house. The two top rooms (chambers) are the atria. The two bottom rooms are the ventricles.
Incidentally, by using this ‘house’ analogy, you can now decipher cardiac terminology. For example, atrial (top chamber) fibrillation (quivering) or left ventricular (bottom chamber) dysfunction (weakness) or premature ventricular (bottom chamber) contractions (heart beats), etc.
Just like a home the heart has electrical wiring. Cardiac electrical problems are known as arrhythmias. Cardiologists who specialize in arrhythmias are electrophysiologists (electricians).
The heart’s ‘plumbing’ are the coronary arteries. The interventional cardiologist is your plumber.
The heart valves are the 'doors' which are best viewed with echocardiography, and the carpenter is your cardiac surgeon.
The role of the general cardiologist, your general contractor, is to oversee the entire health of your heart: diagnosis, monitoring, treatment and coordinating with subcontractors (subspecialty cardiologists) when required.
In keeping with our 'house' analogy: the living room is your left ventricle. The aorta is the hallway leading from the living room. The aortic valve is the door between the living room (left ventricle) and the hallway (aorta).
Aortic stenosis or AS = the stuck door that separates the living room from your hallway.
Causes of Aortic Stenosis
Your heart beats over 100,000 times a day. If you are 70, try opening and closing any door 100,000 times a day for 70 years. The wear and tear on the valve results in either the door becoming stuck (stenosis) or closing improperly (regurgitation). The body’s ‘rust’ is calcium deposits. These build up on the aortic valve causing it to either stick (stenosis) or leak (regurgitation). So now you know the two problems that valves can have: stenosis and regurgitation.
Stenosis = stuck (Imaging your front door having rust on the hinges making it difficult to open the door)
Regurgitation = leaking (your front door doesn’t close properly allowing air conditioning to escape)
The most common cause of aortic valve stenosis (stuck aortic valve) is wear and tear due to age. This is known as degenerative or calcific aortic stenosis.
Another cause is being born with a defective aortic valve. The aortic valve is a three piece (leaflet) structure. In about 2% of the population, a couple of the parts are fused together and this is known as a bicuspid aortic valve. People born with a bicuspid valve generally have aortic valve problems at an early age and may have problems with their aorta.
Rarely, these days, an infection as a youngster may result in the valve becoming damaged later in life (rheumatic heart disease).
Summary: most aortic stenosis is due to wear and tear on the valve over time: calcific aortic (degenerative) stenosis. It is not inevitable that people will develop aortic stenosis.
Severity
Cardiologists grade aortic stenosis in terms of degree. We have various measurements by echo and cardiac catheterization that help characterize severity: Mild, Moderate, Severe/Critical. Aortic stenosis is diagnosed with an echocardiogram and aided by supplemental tests.
Mild aortic stenosis: Observation. Your cardiologist may recommend an echo be repeated very 1-2 years, more or less, to keep an eye on things.
Moderate AS: Observation. Cardiologist performs an annual echo and monitors for symptoms.
Severe AS: Valve replacment. Patients who develop symptoms such as chest pain (angina), shortness of breath/water in the lungs (CHF), fainting (syncope) with moderate or severe aortic stenosis will require aortic valve replacement. In preparation for valve replacement, you will undergo serial echocardiograms, transesophageal echo (TEE), and a left and right heart cardiac catheterization.
Symptoms
As noted above, there are three symptoms being monitored for: chest pain, shortness of breath, dizziness. Symptomatic aortic stenosis is an indication for valve replacement.
Treatment
As noted, symptomatic severe aortic stenosis (AS), requires valve replacement surgery. Some valves are so critically tight that even without symptoms, replacing the valve is warranted. In situations where patients experience symptoms, yet the stenosis is not severe, additional studies such as dobutamine echocardiography may be performed.
There are three treatments for severe aortic stenosis
Observation (serial echo, monitoring for symptoms) for the asymptomatic patient who declines valve replacement.
Types of Artificial (Prosthetic) Valves
For an excellent summary, please visit the Cleveland Clinic website.
Artifical valves are either tissue or metal. Both require antibiotics to prevent infection prior to dental cleaning/procedures and metal (mechanical) valves requires blood thinners in addition to aspirin.
Two Types of Artificial Valves:
1. Tissue (Bioprosthetic) Valves
-Do not require anticoagulation (blood thinners), but tends to need replacement in about 10-20 years. They will need to be replaced when they develop wear and tear.
2. Mechanical (Metal) Valves
-Require anticoagulation (blood thinning) with coumadin/warfarin. These valves are designed to last your entire life.
Post Aortic Valve Replacement Follow up:
Following your recovery aortic valve surgery or TAVR after the usual post-procedure care provided by interventional cardiology or cardiac surgery, your general cardiologist will be monitoring you for symptoms (serial echocardiograms, monitoring for arrhythmias) and preventing infections:
1. Protection Against Infection
An infection of a heart valve is called SBE or bacterial endocarditis and is life-threatening.
Antibiotics are given to all valve patients prior to going to dental procedures to prevent bacteria from attacking the artificial heart valve.
2. . Anticoagulation
Aspirin: Aspirin is recommended for patients with mechanical/metal heart valves and optional with bioprosthetic/tissue valves.
Warfarin: For mechanical valves: asa 81mg with warfarin is recommended by the American Heart Association. However, patients who are unable to maintain stable INR may have bleeding complications.
Summary:
Aortic Stenosis refers to a restricted valve opening due to wear and tear of the valve. Less common causes include a bicuspid/congenital defect or, even rarer, rheumatic heart disease.
Symptoms: Chest pain, Fainting, Shortness of breath.
Treatment of Severe Aortic Stenosis: Valve replacement.
Valve Replacement: TAVR vs. Open surgical replacement
Types of Replacement Valves:
Mechanical: anticoagulation and asa.
Bioprosthetic: no anticoagulation just asa.
SBE prophylaxis: for all patients who have had valve replacement/repair or previous valve infection.
Excellent Websites You Should Visit To Learn More About Aortic Stenosis
After reading this post, visit the excellent websites which I have pre-screened for you. They have high quality content and useful videos.
Note: Understanding your heart condition is not difficult. Patients become frustrated and confused when doctors don’t explain things clearly. If you don’t understand what your doctor is talking about, then you won’t be able to ask meaningful questions. I hope that my posts provide you with a framework that you can build upon to become an active participant in your healthcare.
Stay Healthy!
Gregg M. Yamada MD FACC
Disclaimer: I hope you find my medical blogs to be educational, pertinent, interesting, and thought provoking. The information provided is educational and should not be taken as medical advice. I am a doctor, but I am not your doctor. Please schedule an appointment with your doctor to discuss these issues and to determine what is right for you.
© 2019. Gregg M. Yamada, MD FACC. All rights reserved