Clinical Practice Guideline

for

MITRAL VALVE PROLAPSE

Developed for the

Aerospace Medical Association

by their constituent organization

American Society of Aerospace Medicine Specialists

 

Overview: The prevalence of mitral valve prolapse (MVP) is reported to be 2-5% in the general U.S. population.  In a USAF database of echocardiograms (echo) performed on pilot training candidates, the prevalence of MVP has been about 0.5% in males and females.  This lower prevalence may partly be due to the young age of this population and also due to elimination of some more obvious cases in the pilot training examination process.  MVP may be diagnosed or suggested by the typical auscultatory finding of a midsystolic click with or without late systolic murmur, but by current standards it is more typically an echocardiogram (echo) diagnosis.  Echo criteria have evolved significantly over the years, but current standards are widely accepted and unlikely to change significantly in the near future.

 

Progressive mitral regurgitation (MR, also termed mitral insufficiency) is one of the primary clinical and aeromedical concerns for MVP.  Abnormalities of the mitral valve annulus, the valve leaflets, the chordae tendinae, or the papillary muscles can cause MR.  In the United States and much of the Western world, the most common cause is MVP, accounting for as much as one-half to two-thirds of MR cases.  In the aircrew population clinically significant MR is also most commonly associated with mitral valve prolapse/myxomatous mitral valve disorder.  Other causes include rheumatic heart disease, endocarditis, ischemic heart disease, collagen vascular disease, and dilated cardiomyopathy.  Primary MR is mitral regurgitation in the absence of any apparent underlying etiology.  Primary MR is considered in a separate waiver guide (Mitral Regurgitation – Primary).  Aeromedical considerations for other etiologies of MR will be addressed per the underlying disease process and the primary MR waiver guide.  This waiver guide will limit discussion to MVP.

 

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 included, but are not limited to, mitral valve prolapse, bicuspid aortic valve, mitral or aortic regurgitation with normal valve and uncorrected small defects of the atrial and ventricular septum.

 

Aeromedical Concerns: Two categories of aeromedical events must be considered with MVP.  Events which might occur abruptly and impact flying performance include sudden cardiac death, cerebral ischemic events, syncope/presyncope and sustained supraventricular and ventricular tachydysrhythmias.  Other aeromedical concerns include progression to severe mitral regurgitation (MR), requirement for surgical mitral valve repair or replacement, other thromboembolic events and nonsustained tachydysrhythmias.  Review of US Air Force experience with 404 trained aviators with MVP yielded event rates of 1.5% per year for all aeromedical endpoints examined.  However, most of these could be readily tracked by serial evaluations and presented a low risk for sudden incapacitation.  For those events which might suddenly impact flying performance, the rate was 0.3% per year.  A subset of this cohort had MVP by auscultation only; all available echos on these aviators did not meet current criteria for MVP.  In this group there were no potentially incapacitating events in the first ten years of follow-up and none of them progressed to severe MR or mitral valve surgery.  In the echo-positive subset, annual event rate at ten years was about 0.5% per year.  None of the 404 had infective endocarditis.  By multivariate analysis the only factors independently predictive of subsequent events were dilation of the left ventricle or left atrium and age older than 45 years at time of initial diagnosis.

 

Static or isometric exercises may worsen MR and thus have deleterious effects.  In general, exercise produces no significant change or a mild decrease in MR because of reduced systemic vascular resistance.  However, patients with elevation of heart rate or blood pressure with exercise may manifest increased MR and pulmonary capillary pressures.  Hence, static exercise that increases arterial pressure is potentially deleterious.  Ejection fraction usually does not change or decreases slightly with exercise, although the ejection fraction response may be completely normal in younger, asymptomatic subjects.  These concerns may be more theoretical than documented, but result in recommendation for restricted static exercise in competitive athletes with significant MR due to any cause.  In the aeromedical environment, “pulling” Gs is a similar situation and thus reduced +Gz tolerance and +Gz-induced tachydysrhythmias would be concerns with severe MR.  In the ACS MVP database review, 95 aviators had a monitored centrifuge assessment.  Nonsustained supraventricular tachycardia and nonsustained ventricular tachycardia each occurred in one individual (1/95, 1%).  G-loss of consciousness occurred in two individuals (2/95, 2%) without associated dysrhythmia in either case.  These occurrences are less than that reported for apparently healthy centrifuge subjects or trainees.  A slight reduction in +Gz tolerance has previously been reported for MVP but was operationally nonsignificant.  Monitored centrifuge assessment is no longer required for MVP.  Unrestricted waiver may be considered for MVP with associated moderate or less MR; waiver consideration for severe MR is limited to low performance aircraft.

 

Medications to reduce afterload, such as ACE inhibitors, have documented clinical benefit in acute MR and chronic aortic insufficiency, but no studies have shown such a clinical benefit for MVP with significant chronic MR.  Although some studies have shown hemodynamic improvement and relief of symptoms, this has not been shown to delay the need for surgery or improve surgical outcome, as is the case for severe aortic insufficiency. Use of these medications in asymptomatic MR may or may not be beneficial, but is probably common clinical practice.  Use in symptomatic MR is appropriate, but at that stage the aviator should be disqualified; aeromedical disposition should be secondary to consideration of proper timing of valve surgery.  The use of approved ACE inhibitors is acceptable in aviators with MVP and moderate or asymptomatic severe MR.

 

Medical Work-up: Recommended medical work-up for aviators with MVP involves a complete history and physical examination – to include detailed description of symptoms, medications, activity level and CAD risk factors (positive and negative).  Further documentation should include a report and complete tracing of the echo documenting the MVP diagnosis and copies of reports and tracings of any other cardiac tests performed locally for clinical assessment (e.g. Holter, treadmill, stress echocardiogram).  Finally, a report from the physician caring for the aviator is highly recommended.

 

Aeromedical Disposition:

 

Air Force: MVP is disqualifying for flying classes I/IA. II, and III.  For FC IIU and ATC/GBC duties, it is disqualifying if the condition is symptomatic.  SMOD personnel are covered under retention standards for symptomatic MVP requiring treatment.  ACS review is required for waiver consideration.  ACS evaluation may be required, depending on the flying class or for specific concerns in an individual case.  Waiver considerations will usually be determined by the presence and severity of associated MR.  MVP with mild or less MR is eligible for FC I/IA waiver.  MVP with moderate or less MR is eligible for unrestricted FC II/III waiver.  MVP with asymptomatic severe MR that does not yet meet published guidelines for surgery may be considered for waiver restricted to low performance aircraft.  MVP with symptomatic severe MR or with asymptomatic severe MR that meets published guidelines criteria for surgical repair or replacement is disqualifying without waiver recommendation.  ACS re-evaluations will be performed at 1-3 years intervals, depending on degree of MR and other related considerations, such as cardiac chamber dilation and left ventricular function.  As discussed above, the use of approved ACE inhibitors for afterload reduction is acceptable in aviators with MVP and moderate or asymptomatic severe MR.

 

Additional considerations for waiver recommendation include but are not limited to: normal left ventricular and left atrial size, normal left ventricular function, no prior thromboembolic events, no associated tachydysrhythmias and no symptoms attributable to MVP.  Associated tachydysrhythmias will be addressed per their appropriate waiver guide and on a case-by-case basis.  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.  Each waiver recommendation will specify requirements and timing for waiver renewal.

 

Army: History of valvular heart disease, to include mitral valve prolapse (MVP), as documented by clinical or electrocardiographic findings is disqualifying for flight duty. MVP is discussed in the APL of that name.  Army concerns mirror those of the Air Force in that the associated signs and symptoms of mitral valve prolapse syndrome are more dangerous that an uncomplicated mild valvular prolapse alone.  Applicants for flight training with a history of MVP are reviewed on a case by case basis and are occasionally waivered if mild and stable after thorough evaluation.  Rated aircrew are generally evaluated individually, but favorably considered in the presence of only mild mitral regurgitation and no significant dysrhythmia.  Surgically corrected MVP, even if minimally invasive, is non-waiverable.

 

Navy: Candidates/applicants with MVP are not recommended for waiver, except for air traffic controllers. Designated personnel with MVP and minimal regurgitation, who do not require medication and do not have a history of significant arrhythmias may be considered for waiver.  Beta blockers have been used to reduce the subjective sensation of palpitations, but their use is Considered Disqualifying (CD) with no waiver recommended.

Information required for waiver consideration:

1. Cardiology consultation is required to include:

            a. Physical exam

b. Exercise stress testing

c. Holter monitoring

d. Echocardiogram.

2. "Echo only" MVP does not meet Navy criteria for diagnosis of MVP syndrome (click, murmur

and prolapse in two echo views), but may be sufficient to result in disqualification from flight

duties. Because of conflicting interpretations by local clinicians, all cases of suspected MVP will

be reviewed by NAMI Internal Medicine.

3. A Local Board of Flight Surgeons is thus inappropriate until NAMI has reviewed the case (not via phone consult).

 

Civilian: MVP is not disqualifying in civil aviation.  Echocardiograms are not part of a routine FAA medical examination.  Should an AME feel an airman has MVP, they should obtain an echocardiogram and cardiovascular evaluation.  If there is evidence of mitral regurgitation, the presence/absence of chamber enlargement may determine whether the airman will be able to get an authorization. This condition does require an authorization.  The AME will likely be granted permission to follow the airman yearly. 

 

Waiver Experience:

 

Air Force: Review of AIMWTS revealed 214 cases of mitral valve prolapse with a total of 23 disqualifications.  Of the total cases, 9 were FC I/IA (3 disqualifications), 126 were FC II (9 disqualifications), 76 FC were III (9 disqualifications), 2 were ATC (1 disqualification), and 1 was SMOD (1 disqualification).  Of the 23 disqualified, three were due to MVP with mild MR (all FC I/IA {disqualifying at the time}), three were due to symptomatic mild MR, one was due to mod-severe MR, ten were due to MVP and other cardiac abnormalities (e.g. other valve disease, cardiomyopathy, atrial fibrillation, coronary artery disease, recurrent atrial tachycardia, annuplasty/chordae repair) and six were due to other medical conditions.

 

Army: Mitral valve prolapse has been a relatively uncommon diagnosis among rated Army aviators.  Between 2009 and 2011 there was an average rated aviator population of 14919 as identified by having an annual flight physical.  During this period, there was an average of 30 cases carrying the diagnosis of mitral valve prolapse in any given year, yielding an average one year period prevalence of 20 cases per 10,000 aircrew.  During the period of this study there was an average incidence of 1 case per year among both applicants and rated personnel.  Of the 3 applicants, one was given a waiver.  Of the 3 rated aviators, two were given waivers

 

Navy: Not available at this time

 

Civilian: As of December 2011 there are 447 first-, 260 second-, and 960 third-class airmen currently issued with Mitral Valve Prolapse. 

 

ICD 9 codes for mitral valve prolapse

394.9

Other and unspecified mitral valve disease

424.0

Mitral valve disorders

 

References:

 

Kruyer WB.  Cardiology.  In: Rayman RB, ed. Clinical Aviation Medicine, 4th ed. New York: Graduate Medical Publishing, LLC.  2006; 199-201.

 

Davis, JR, et al. Fundamentals of Aerospace Medicine, 4th ed.  Philadelphia: Lippincott Williams & Wilkins.  2008; 339-340.

 

Wilson W, chair.  Prevention of infective endocarditis: Guidelines from the American Heart Association.  Circulation.  2007; 115:  1-19.

 

Osswald SS, Gaffney FA, Kruyer WB, Pickard JS, Jackson WG.  Analysis of aeromedical endpoints and evaluation in USAF aviators with mitral valve prolapse.  Submitted for publication.

 

Osswald SS, Gaffney FA, Hardy JC.  Mitral Valve Prolapse in Military Members: Long-term Follow-up and Clinical Risk Analysis.  J Am Coll Cardiol.  1997 Feb; 29(Suppl A):  506A.

 

Bonow RO, Cheitlin MD, Crawford MH, Douglas PS.  36th Bethesda conference: Eligibility recommendations for competitive athletes with cardiovascular abnormalities.  Task force 3: Valvular heart disease.  J Am Coll Cardiol.  2005; 45(8):  1334-40.

 

Whinnery JE.  Dysrhythmia comparison in apparently healthy males during and after treadmill and acceleration stress testing.  Am Heart J.  1983; 105:  732-737.

 

McKenzie I, Gillingham KK.  Incidence of Cardiac Dysrhythmias Occurring During Centrifuge Training.  Aviat Space Environ Med.  1993; 64:  687-91.

 

Whinnery JE. Acceleration Tolerance of Asymptomatic Aircrew with Mitral Valve Prolapse. Aviat Space Environ Med. 1986;57:986-92.

 

Whinnery JE, Hickman JR.  Acceleration Tolerance of Asymptomatic Aircrew with Mitral Valve Prolapse and Significant +Gz-induced Ventricular Dysrhythmias.  Aviat Space Environ Med.  1988; 59:  711-7.

 

Whinnery JE.  Acceleration-Induced Ventricular Tachycardia in Asymptomatic Men: Relation to Mitral Valve Prolapse.  Aviat Space Environ Med.  1983; 54(1):  58-64.

 

Bonow RO, chair.  ACC/AHA 2006 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.  J Am Coll Cardiol.  2006; 48(3):  e1-e148.

 

 

 

Prepared by Drs. Michael Madrid, Dan Van Syoc, and William Kruyer

May 21, 2012