Athletics Magazine

More on Athletes and Bicuspid Aortic Valve (BAV)

By Lcreswell @athletesheart
More on Athletes and Bicuspid Aortic Valve (BAV)
I probably get more inquiries from athletes with bicuspid aortic valve (BAV) than any other single heart problem.  Maybe that's not surprising, given that I'm a heart surgeon and that many individuals with BAV need operation at some point.  Nonetheless, I think there's considerable confusion about this condition, in terms of diagnosis, implications for the athlete, and its treatment.
I first wrote about BAV in a short post here at the blog back in 2009.  That post is a starting point for today's discussion.
To quickly review, individuals with BAV have an aortic valve with 2 unequal--instead of the usual 3 equal sized--leaflets.  As a consequence, these individuals develop earlier calcification of the valve leaflets, leading to narrowing, or stenosis.  They are also predisposed to enlargement of the ascending aorta, the large blood vessel that carries blood flow away from the heart.  This can lead to stretching apart of the valve leaflets and leakage at the valve, known as regurgitation.
Looking through the reader comments here at the blog and reflecting on the athlete inquiries I've received, I thought I'd cover some of the major issues.
First, you're not alone!

BAV is one of the most common congenital heart conditions, occurring in about 2% of individuals.  In large-scale pre-participation cardiac screening programs for young, competitive athletes, BAV is one of the most commonly identified abnormalities.
Historically, a heart murmur was the most common reason affected individuals were identified.  Today, echocardiography (ultrasound) for screening or diagnostic purposes for some other heart problem is the most common way that BAV is detected.
Finally, athletes are not spared.  Several contemporary elite triathletes have BAV and I've written about their stories in:
Examples from other sports would include Arnold Schwarzenegger, among others.
And of course the problem occurs in everyday, recreational athletes, too.  Check out Anthony DiLemme's blog, Anthony's Heart Valve Replacement Saga.  He's a 30-year-old 8th grade science teacher, a cyclist and outdoorsman, who is chronicling his story with BAV--from diagnosis, to evaluation, to preparations for upcoming valve replacement surgery.  His story is typical.
On the bright side, there is ample evidence that, in the modern era, life-expectancy is not shortened for individuals with BAV compared to the general population.  That's important to keep in mind.
Before operation is needed
It's worth knowing if you have BAV.
Aside from the problems with aortic valve stenosis or regurgitation or with enlargement of the aorta, individuals with BAV can also suddenly develop the problem of aortic dissection.  With aortic dissection, the aorta can develop a tear on its inside wall, leading to unraveling of its layers, and even rupture.  This is thought to occur at a rate of about 0.1% per year in adults.  This can be a life-threatening problem and is more apt to occur with progressive enlargement of the aorta and with uncontrolled high blood pressure.
The American College of Cardiology (ACC) in conjunction with the  American Heart Association (AHA) has issued guidelines for the evaluation, monitoring, and treatment of individuals with BAV:
  • Patients with known BAV should undergo:
    • An echocardiogram to evaluate the aortic valve for stenosis or regurgitation and to assess for any other structural heart problems
    • A chest CT scan to make measurements of the diameter of the aorta at various points along its length.
  • Cardiac CT scan or magnetic resonance imaging (MRI) are alternatives if echocardiography is not available or possible for some reason
  • If there is enlargement of the beginning portion of the aorta to greater than 4.0 cm, the individual should have a yearly assessment of the diameter of the aorta
  • Medical therapy may be useful to slow or halt the progression of aortic valve disease and aortic enlargement by reducing the blood pressure and the blood pressure across the aortic valve.  Beta-blockers (eg, metoprolol) are recommended for this purpose.
  • Because BAV may be an inherited condition, first-degree relatives of individuals with BAV should undergo evaluation.
In my opinion, these are useful guidelines for athletes and non-athletes, alike.  The guidelines do not address the frequency of surveillance for individuals with BAV and no enlargement of the aorta.  For these individuals, provided there is no other relevant heart disease, it may be appropriate to have follow-up echocardiogram and/or CT scanning every 2 years.
The data regarding the progression of disease in athlete patients with BAV are limited.  Guidelines specifically for athletes come from the Proceedings of the 36th Bethesda Conference in 2005.  Parenthetically, it may be time for an update.  The guidelines were developed by an expert panel based on the scientific information available at that time:
  • Athletes with BAV, no significant valve stenosis or regurgitation, and an aortic diameter less than 4.0 cm can participate fully in their sport(s)
  • Athletes with BAV and enlargement of the aorta to between 4.0 and 4.5 cm can participate safely in only low and moderate intensity sports (this would exclude the typical endurance sports of swimming, cycling, running, triathlon, etc.)
  • Athletes with BAV and enlargement of the aorta to greater than 4.5 cm can participate safely only in low intensity sports (eg, golf, bowling, billiards).
The issue has not been studied very well, but one recent study suggests that continued participation in sports for periods of up to 5 years does not change the natural history and progression of BAV.  Instead, even with continued sports participation, the progression of both valvular and aortic disease is no different from that in the general population.
Who needs operation?
Operation is needed if there is severe aortic valve stenosis, severe valve regurgitation, or significant enlargement of the aorta.  Again, there are ACC/AHA guidelines for when operation is needed:
  • Aortic valve replacement is recommended for nearly all patients with severe valve stenosis (valve opening less than 1.0 cm2)
  • Aortic valve replacement is recommended for patients with severe valve regurgitation if there are symptoms due to the regurgitation (eg, shortness of breath with exertion) or evidence that the heart is suffering because of the regurgitation (enlargement of the left ventricle)
  • Repair or replacement of the beginning portion of the aorta is recommended if there is enlargement of the aorta to greater than 5.0 cm or if the rate of increase in the aortic diameter exceeds 0.5 cm per year
Sometimes more than one indication for operation may be present, so there is the additional guideline for patients who need operation for aortic stenosis or regurgitation:
  • In patients needing valve replacement because of stenosis or regurgitation, the aorta should be repaired or replaced if the aortic diameter exceeds 4.5 cm.
I know from discussion with athletes over the past few years that there are differences of opinion among cardiologists and heart surgeons about these guidelines.  These differences of opinion may be legitimate.  Consensus guidelines are developed to be broadly applicable, but the guidelines may not be applicable in a given athlete patient's circumstance.  There are a multitude of patient-specific circumstances that must be considered when deciding if and when operation is needed.  Only your cardiologist and heart surgeon will be in a position to make those considerations.
In practice, the indications for aortic valve replacement for severe aortic stenosis or severe aortic regurgitation are straightforward and uncontroversial.  It's also clear-cut that patients with significant enlargement of the aorta to greater than 5.0 cm need operation for replacement of the aorta.
One situation that seems particularly ripe for differences of opinion is that of the athlete with BAV, no significant stenosis or regurgitation, but with an aortic diameter of 4.5 to 5.0 cm.  This is an unfortunate situation for the athlete patient because the consensus guidelines do not yet recommend operation, yet advise against strenuous sports activities.  My personal approach to endurance athletes in this situation would be to offer operation if the patient wanted to continue to participate in endurance sports (after operation) and was willing to assume the risks of operation.  But I recognize that not all cardiologists or heart surgeons would agree.
Options for operation

Substitute valves.  There are 2 broad categories of heart valve substitutes that can be used to replace the human aortic valve:  mechanical valves or bioprosthetic ("tissue") valves.
  • Mechanical valve.  These valves are constructed from high-tech materials that are designed to last essentially forever.  Unfortunately, these materials may cause tiny blood clots to form on their surface and, for that reason, patients must take blood-thinning medications (eg, warfarin) forever to prevent this complication.  The major brands include St. Jude Medical, Medtronic, Sorin-Carbomedics, and On-X.
  • Bioprosthetic valve.  This type of valve is made primarily from animal tissues.  One example is the aortic valve "borrowed" from a pig.  Another example is a valve that is made from "fabric" borrowed from the pericardium of the cow.  These valves have the advantage that blood clots are much less likely to form on their surface, so patients do not need to take blood-thinning medications (other than, perhaps, aspirin) in the long term.  They have the disadvantage that they do not last forever.  Young patients who receive these valves may need to have the valve re-replaced because it "wears out" at some point.  The major manufacturers include Medtronic, St. Jude Medical, and Edwards Lifesciences.
Aortic replacement.  When the aorta is enlarged in the setting of BAV, there are a couple possibilities:  the valve needs to be replaced--or it doesn't:
  • With valve replacement.  When the aorta needs to be replaced along with the aortic valve, we call this procedure an aortic root replacement.  This is a complicated operation technically and must be tailored very carefully to the patient's specific situation.  Options include:
    • Mechanical valve conduit.  Products are available that combine a mechanical valve attached to a Dacron fabric tube.  This is used, as a unit, to replace the patient's aortic valve and beginning portion of the aorta.  The coronary arteries are re-implanted into the Dacron tube.  Of the options listed here for aortic root replacement, this is by far the most common.
    • Bioprosthetic valve conduit.  This is not commercially available, but can be assembled in the operating room.  The operation is like described above for the mechanical valve conduit.
    • Medtronic Freestyle valve.  This is a unique product that is a porcine aortic root that can be used to replace the human patient's aortic root, like the other operations above.
    • Ross procedure.  This is the most technically complicated option.  The patient's aortic valve and beginning portion of the aorta are removed.  The patient's own pulmonary valve is removed and then used to replace the aortic valve and beginning portion of the aorta.  The coronary arteries are re-implanted into the pulmonary valve trunk.  A cryopreserved pulmonary allograft (the pulmonary valve and trunk from a human cadaver) is then used to replace the patient's pulmonary artery.
  • Without valve replacement.  When only the aorta must be replaced, a Dacron fabric tube is used.
Valve repair.  There is recent interest and experience with aortic valve repair--instead of replacement--for patients with BAV.  These techniques are most applicable to situations in which there is regurgitation, rather than stenosis, of the valve and when there is also enlargement of the aorta.  To help correct the regurgitation, the cusps of the patient's valve leaflets can be tailored, with the valve leaflets left in place.  Then, a Dacron fabric tube can be used to reconstruct the aorta, in a so-called valve-sparing aortic root replacement.  This procedure has the particular benefit that no artificial valve (with the disadvantages described above) needs to be used.  The potential downside relates to durability.  Questions currently remain about how long such repairs will last and whether patients might require re-operation at some point in the future.  This valve repair option is one that might best be pursued at a center that specializes in this problem.
After operation
The recovery from heart surgery can be hard to predict for any given patient, but we know that young otherwise healthy patients tend to do well.  Most patients spend about a week in the hospital after operation and then are able to go home.
Early after operation, and for perhaps the first month, we typically limit activities that place stress on the shoulders and sternum.  This gives a chance for the sternum, which was split during the operation, to heal completely.  So for that first month, we usually advise no driving, lifting, pulling, pushing, reaching, etc.  During that first month we recommend ample walking as the best form of exercise.  After the first month, patients are generally allowed to return gradually to all of their previous activities.
Patients who've had aortic valve replacement and/or replacement of the aorta will require life-long monitoring by their doctor, with periodic echocardiogram and/or chest CT scanning.  Over time, there will be some patients who develop problems with the prosthetic heart valve or enlargement of some portion of the aorta (that hasn't already been replaced) that requires operation.
Athletes will ask when they can return to their sports.  Consensus guidelines from the Proceedings of the 36th Bethesda Conference recommend:
  • Athletes with mechanical or bioprosthetic heart valves may participate in low and moderate intensity sports
  • Athletes who are taking blood-thinning medications should avoid sports where bodily injury, with potentially life-threatening bleeding, might occur
The first recommendation does not include the endurance sports.  The truth is that there is not much scientific information about what happens to such athletes if they do return to endurance sports.  At issue are the potential long-term effects of repeated episodes of high heart rate and high blood pressure that accompany intense exercise.  Unanswered questions include:  Can a bioprosthetic valve wear out more quickly than expected?  Does the (unreplaced) aorta enlarge over time?  If so, how quickly?  Do medications like beta-blockers limit any potential harm?  We just don't know.
Yet I'm personally aware of a good number of athletes who've returned to endurance sport after operations of various sorts for BAV, presumably after discussion with their doctors.  Athletes should have detailed discussion with their doctors about any prudent limitations to exercise after operation and settle on a mutually agreeable plan.
Related posts:
1.  Aortic stenosis and bicuspid aortic valve (BAV)
2.  Elite triathletes and heart problems
3.  Index to blog posts and online articles

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