Clinical
Practice Guideline
for
BICUSPID
AORTIC VALVE
Developed for the
Aerospace Medical Association
by their constituent
organization
American Society of
Aerospace Medicine Specialists
Overview:
Bicuspid
aortic valve (BAV) occurs in 1-2% of the general
In early 2007, the American Heart Association published new
infective endocarditis guidelines that are dramatically different from past
recommendations. Endocarditis
prophylaxis was recommended only for specified high risk groups, and only for
dental procedures, respiratory tract procedures, and procedures on infected
skin, skin structures or musculoskeletal tissue. The high risk group was limited to prosthetic
cardiac valves, previous endocarditis, select congenital heart conditions and
cardiac transplant patients with valvulopathy.
Prophylaxis was no longer recommended for gastrointestinal or
genitourinary procedures. Conditions
commonly seen by most aerospace medicine practitioners were not included in the
list of high risk conditions. Such
common conditions no longer recommended for endocarditis prophylaxis include,
but are not limited to, mitral valve prolapse, bicuspid aortic valve, mitral or
aortic regurgitation with normal valve (e.g. primary MR) and uncorrected small
defects of the atrial and ventricular septum.
Aeromedical
Concerns: Concerns: Aeromedical concerns include
development and progression of AS and/or AI and the risk of infective
endocarditis. Risk of a sudden
incapacitating event is very low and aeromedically acceptable in the absence of
significant AS or severe AI. Waiver
policies are thus primarily dependent on the presence and severity of
associated AS and AI. AI severity is
graded by echo as: trace, mild, moderate
and severe. AS severity
is graded by echo as: mild, mild-to-moderate, moderate and severe.
Medications
to reduce afterload, such as ACE inhibitors, have documented clinical benefit
in chronic AI, including delaying the need for surgery and improvement of
surgical outcome. The use of approved
ACE inhibitors is therefore acceptable in aviators with asymptomatic moderate
and severe AI (check with approval authority for specifics).
Medical Work-up: A complete
history and physical examination is mandatory to include detailed description
of symptoms, medications, activity level and all CAD risk factors (positive and
negative). A copy of the local echo
report and videotape or CD copy of the echo documenting BAV need to be reviewed
by approval authority specialists. Also
important are copies of reports and tracings of any other cardiac tests
performed locally for clinical assessment (e.g. Holter, treadmill, stress
echocardiogram). Depending on the
approval authority and specifics of the case, additional local cardiac testing
is may be required.
Aeromedical
Disposition:
Air Force: BAV is disqualifying for all classes of flying
duties. In the US Air Force, review or evaluation
is required at the Aeromedical Consultation Service for waiver
consideration. As stated above, waiver
recommendations are primarily dependent on the presence and severity of
associated AS and AI.
FC I and IA will only be waived for BAV with ≤ mild
AI and no AS; any greater AI or AS is not waiverable. FC II requires ACS evaluation for waiver
consideration. FC III with trace or no
AI and with no AS may receive a waiver recommendation after ACS review; formal
ACS evaluation will be requested if there is mild or worse AI or any degree of
AS. Other specific concerns about an
individual case may require ACS evaluation.
If the disease process appears mild and stable, waiver for all classes
of flying duties will generally be valid for three years with ACS
reevaluation/review at that time for waiver renewal.
Army:
Bicuspid
aortic valve is not disqualifying in Army Regulation 40-501 Standards of
Medical Fitness, unless there is associated tachyarrhythmia, mitral
regurgitation, aortic stenosis, insufficiency, or cardiomegaly. Army aeromedical policy letter, (APL)
discussion of bicuspid aortic valve articulates the concern that bicuspid
aortic valves become stenotic two-thirds to three-fourths of the time; with
increasing age being the major risk factor.
Pilot applicants are considered for waiver on a case by case basis, but
are usually granted waivers with normal cardiac function. Rated and non-rated Army aviators with
bicuspid aortic valves and no other associated findings are considered
qualified and the condition recorded for information only. Waiver continuation requires submission of a
cardiology evaluation to include echocardiogram with Doppler flow study every 5
years.
Navy: Because congenital
bicuspid aortic valves can degenerate and progress to aortic stenosis or insufficiency,
a bicuspid aortic valve is CD. Waivers will not be considered for applicants.
If an incidental finding in designated aircrew, condition may be waiverable
with possible restriction on aircraft or flight profile.
Civilian: There
is no requirement in the U.S. Civil sector to perform echocardiography on each
airman so unless the airman has a murmur that is detected on examination or
ends up having an echocardiogram performed the FAA would not know. If an airman is discovered to have a bicuspid
aortic valve, they are generally followed using the special issuance process
with status reports and echocardiograms.
For aortic stenosis an airman is disqualified should they
develop a gradient across the valve of 40 mm or the valve area becomes less
than 1 cm2. Aortic insufficiency is also followed with similar requirements and
should the airman develop other problems such as significant chamber
enlargement or atrial fibrillation.
Waiver
Experience:
Air Force: Review of AIMWTS showed 144 cases of BAV; 44 FC I/IA, 76 FC II and 24 FC III. The aeromedical summaries (60) for all disqualified (16) and 44 randomly selected cases were reviewed. Of the 16 BAV cases disqualified, three were FC I/IA, nine FC II and four FC III. Of the 16 BAV cases disqualified, eight were disqualified for BAV and associated cardiac conditions (e.g. moderate to severe AI, dilated aortic root, status post aortic valve replacement due to AI), three for additional cardiac conditions (e.g. coronary artery disease, exercise-induced syncope) and the remaining five for other medical conditions.
Army:
The
Aeromedical Epidemiological Data Repository (AEDR) catalogs all Army flight
physicals since 1960. There have been
approximately 160,000 individual aircrew entered in this database. During this period of time, there have been
76 cases of bicuspid aortic valve discovered, primarily in applicants. Of those, 51 were retained in aviation.
Navy:
Not available at this time
Civilian:
Statistical data on numbers of bicuspid
aortic valve are not kept.
References:
Kruyer
WB. Cardiology. In: Rayman RB, ed. Clinical Aviation Medicine, 3rd
ed.
Kruyer
WB, Gray GW, Leding CJ. Clinical aerospace cardiovascular
medicine. In: DeHart RL,
Bonow
RO, chair. ACC/AHA guidelines for the management of patients
with valvular heart disease. A report of the American
College of Cardiology/American Heart Association task force on practice
guidelines (committee on management of patients with valvular heart disease). J Am Coll Cardiol. 32(5): 1486-588, Nov 1998.
Cheitlin MD,
Douglas PS, Parmley WW. 26th
Wilson
W, chair. Prevention of infective endocarditis: Guidelines from the American Heart
Association. Circulation. 2007; 115: 1-19.
Prepared
by Drs. Bill Kruyer and Dan Van Syoc
11/10/10