What is Aortic Regurgitation (Aortic Insufficiency)?
Aortic regurgitation is the medical term for a leaky aortic valve. It is also known as aortic insufficiency or aortic valve incompetence and is a form of structural heart disease. In this article I will uses the terms aortic regurgitation and aortic insufficiency interchangeably. In severe aortic insufficiency the severe leak can lead to enlargement of the heart and symptoms of heart failure requiring aortic valve replacement. Mild and moderate degrees of regurgitation are usually tolerated well and don’t require treatment or cause symptoms. A tight aortic valve is known as aortic stenosis. Another commonly leaky heart valve is the mitral valve which is known as mitral regurgitation.
What is the Aortic Valve?
The aortic valve is the valve that blood has to go through to leave the main pumping chamber of the heart and get to the body via a large blood vessel called the aorta. Since it is a valve, it stops blood from flowing backward into the heart once it is pumped out. If the aortic valve is leaky, blood can flow backwards into the heart.
What Happens to the Heart in Aortic Regurgitation?
In aortic regurgitation, the leaky aortic valve leads to extra blood flow into the heart. If there are small amounts of leak, the heart hardly notices this. If the leak is larger however, the heart has to grow larger to accommodate the extra blood. Initially this is a good thing as over time it means the aortic insufficiency is tolerated well. Over time however the enlargement can be harmful and lead to failure of the heart muscles and congestion, basically heart failure.
How is Aortic Regurgitation Diagnosed?
Often patients with aortic regurgitation don’t know they have it. The aortic insufficiency is picked up on an ultrasound scan of the heart known as an echocardiogram. Some patients may have a classic murmur of aortic regurgitation that can be heart with a stethoscope. The most common way of diagnosing and following aortic insufficiency is the echocardiogram, an ultrasound scan of the heart.
Acute vs. Chronic Aortic Regurgitation
Acute aortic regurgitation is where there is a sudden event that causes the leak to happen. This is much less common than chronic aortic regurgitation that occurs and progresses over a long time typically. Acute aortic regurgitation, if it is severe, is not handled well. It can lead to congestive heart failure and shock since there is not enough blood going forward to the body. In chronic aortic regurgitation the leak progresses slowly over time and the heart has time to adapt, and so symptoms don’t typically develop for a long time.
Causes of Aortic Regurgitation
Acute aortic regurgitation occurs due to something that can rapidly affect the valve. This includes damage from heart procedures, infection on the heart valve, aortic aneurysm, or conditions that affect the aorta such as aortic dissection where there is a tear in the aorta, the main blood vessel that leaves the heart. Acute aortic insufficiency is not common.
Chronic aortic regurgitation is much more common. This is typically due to disorders of the valve itself, most commonly bicuspid aortic valve or calcified degenerated aortic valve. Sometimes regurgitation can occur as a result of a leak around the prosthetic valve known as paravalvular leak.
Stages of Aortic Regurgitation
Stage A – This is for people who are at risk of developing aortic regurgitation but do not have it yet. This includes patients with bicuspid aortic valve, history of infection on the valve, rheumatic heart disease, and people born with abnormalities of the valve.
Stage B – These patients have mild or moderate aortic regurgitation. The heart function is normal and there are no symptoms. The heart is not significantly enlarged.
Stage C – These patients still have no symptoms, but the aortic valve is severely leaky. The heart pumps relatively normally, however there is clear evidence of enlargement.
Stage D – These patients have both a severely leaky aortic valve and symptoms. The heart is typically significantly enlarged. Symptoms include shortness of breath, particularly on exercise, swelling and fatigue.
Severity of Aortic Regurgitation
Mild regurgitation – This is generally a benign condition, does not cause symptoms and can be found in many people simply by chance. In mild aortic regurgitation less than 30 cc of blood leaks backwards per heart beat. The heart does not generally enlarge in this case.
Moderate regurgitation – This is generally handled well and not associated with symptoms. Typically between 30-60cc of blood leaks backwards per heart beat. The heart may enlarge a little but not a concerning amount. This should be followed over time to ensure severe disease doesn’t develop.
Severe regurgitation – This is often handled well, although after some time heart enlargement and symptoms typically develop. Over 60cc of blood leaks backwards per heart beat. In patients with symptoms or evidence of heart failure, aortic valve replacement is generally recommended. In patients with no symptoms, regular surveillance is required to ensure no development of heart dysfunction.
Medical Treatment of Aortic Regurgitation
In general patients with aortic regurgitation should have attention paid to blood pressure. High blood pressure should be treated with a goal of < 140mmHg with medicines known as calcium channel blockers or ACE inhibitors being preferred. An example of a calcium channel blocker would be amlodipine. An example of an ACE inhibitor would be Lisinopril. In patients with severe aortic insufficiency, beta-blockers are generally not used as they lead to lower heart rate, which means more time for the heart to fill with leaking blood with each beat.
Indications for Surgery in Patients with Aortic Regurgitation
Although some patients with severe aortic insufficiency may be able to have their valves fixed, the majority will require aortic valve replacement. In the future the TAVR procedure may become an option for aortic regurgitation.
Symptoms – In general, the development of symptoms is an indication for surgery for aortic regurgitation. Patients with severe aortic insufficiency and symptoms of heart failure have a significantly increased risk of death. These symptoms include fatigue and shortness of breath.
Heart Dysfunction – Patients that have severe aortic insufficiency and are found to have reduced heart pumping function, even in the absence of symptoms. This strategy is associated with better outcomes than waiting for worse heart dysfunction or the development of symptoms in these patients.
During Surgery for Other Heart Conditions – Patients with severely leaky aortic valve should have the aortic valve replaced if they are undergoing cardiac surgery for any other conditions including bypass surgery for heart blockages or other valve surgery.
Heart Enlargement – Even if there are no symptoms and the heart function is normal, if the heart is noted to enlarge significantly surgery can be considered. Particularly if there is a low risk of undergoing surgery.
Aortic Regurgitation Summary
Aortic regurgitation is a leaky aortic valve. When mild or moderate it is not typically of concern. Severe insufficiency can lead to heart enlargement and symptoms of heart failure so it needs to be watched closely. Severe aortic regurgitation with symptoms typically requires aortic valve replacement.