Clinical Practice Guideline
for
AORTIC VALVE STENOSIS
Developed
for the
Aerospace
Medical Association
by their
constituent organization
American
Society of Aerospace Medicine Specialists
Overview: Aortic
stenosis (AS) usually occurs at the level of the aortic valve. Supravalvular and subvalvular forms of AS
exist but are unusual congenital defects unlikely to present as a new diagnosis
in an adult military aviator/aircrew.
These would be addressed aeromedically on a case-by-case basis. Valvular AS has several causes. In older adults the most common is senile AS,
an aging-related calcifying, degenerative process. In the military aviator/aircrew population
the most common cause will be associated bicuspid aortic valve. AS will still be unusual in military
aviator/aircrew with bicuspid aortic valve because this complication usually
occurs in middle-aged or older patients.
Bicuspid aortic valve (BAV) occurs in 1-2% of the general
Aeromedical Concerns: While the diagnosis may be suspected
by careful auscultation, AS is primarily an echocardiographic (echo)
diagnosis. On echo AS is graded by a
combination of mean pressure gradient across the stenotic valve and calculated
valve area. Grading categories are mild,
mild-to-moderate, moderate and severe.
Aeromedical concerns for AS include infective endocarditis, progression
to significant stenosis and requirement for aortic valve replacement or
repair. The prognosis of mild AS is good
for at least five years after diagnosis.
Once AS has progressed to moderate or severe, aeromedical and clinical
concerns also include sudden cardiac death, syncope, angina and dyspnea. Angina may occur in the absence of
significant coronary atherosclerosis.
Dyspnea is due to left ventricular dysfunction. Event rates are 5% and 10% per year for
asymptomatic and symptomatic moderate AS, respectively. Event rates are considerably higher for
severe AS.
Medical Work-up: An initial waiver can be
considered following the review and/or evaluation by the Aeromedical
Consultation Service (ACS). Please refer
to items A through D, listed below, as the most commonly requested clinical
data.
B. Copy of the local echo report and videotape or CD copy of
the echo (required for ACS confirmation of the diagnosis).
C. Additional local cardiac testing is not routinely
required but may be requested in individual cases.
D. Copies of reports and tracings of any other cardiac tests
performed locally for clinical assessment (e.g. electrocardiogram (ECG),
treadmill, Holter monitor).
Waiver renewal
requires an interval AMS with particular attention to clinical signs and
symptoms. No studies are required prior
to the ACS evaluation for renewal except for FCIII renewal for BAV with trace
AI and no AS. In that case a local
echocardiogram needs to be sent to the ACS for review. If studies were accomplished during routine
work-up, submit with waiver package.
Civil Aviation
Medicine (Federal Aviation Administration): The FAA grants medical
certification for all classes for aortic stenosis. The follow up requirements are a yearly
echocardiogram. Once the gradient across
the aortic valve reaches 40 mm Hg or the valve area is less than 1.0 cm2 the
airman is denied and will not gain medical certification until they have a
valve replacement.
Aeromedical
Disposition (military): Table 1 is a summary of the clinical
manifestations and most common requirements for the separate flying class (FC)
duties.
Table 1. Summary of Degree of Aortic Stenosis and ACS
Requirements.
|
Associated Levels of Aortic
Stenosis (AS) |
Flying Class |
Waiver Issued Waiver Authority |
Required ACS Review and/or ACS
Evaluation |
|
mild AS |
FCI and
IA |
No AETC Yes MAJCOM |
FCI/IA:
ACS evaluation FCII/III:
ACS evaluation |
|
mild-to-moderate
AS |
(low G-
aircraft) (low G-
aircraft) |
Yes AFMSA Yes MAJCOM |
|
|
> moderate AS |
All
Flying Classes |
No |
N/A MEB
required |
Initially,
waiver will typically be valid for one year with ACS reevaluation required for
waiver renewal consideration. If AS is mild
and appears stable after several ACS evaluations, waiver recommendation by the
ACS may be extended to
Aeromedical Disposition (civilian):
In the FAA once the valve has been replaced the airman is required to be
grounded for six months immediately following the surgery. At that time the airman must undergo a
maximal nuclear stress test for either first- or second-class certification and
a plain
Follow up testing is required yearly for all classes. It consists of current status report, twelve
lead electrocardiogram tracings, 2-D echocardiogram, lipid panel and fasting
blood sugar.
In the civil sector airmen are permitted to fly while being treated with
Warfarin anticoagulation. Should the
airman require Warfarin anticoagulation for a mechanical valve they are
required to have International Normalized Ratios of between 2.5 and 3.5.
The FAA also permits the airman with aortic stenosis to be treated with
the
Waiver Experience (military): In the
Waiver
Experience (civilian): As of March 15, 2007 currently issued airmen
with mechanical aortic valve replacement: first-class 33, second-class 33, and
third-class 139. Currently issued airmen
with tissue aortic valve replacement: first-class 36, second-class 35, and
third-class 172.
References.
1.
2.
3.
4.
March 19, 2007