Clinical Practice Guideline

for

CONGENITAL HEART DISEASE

Developed for the

Aerospace Medical Association

by their constituent organization

American Society of Aerospace Medicine Specialists

 

Overview: Congenital heart disease in adults includes common and uncommon defects, with and without correction by surgery or catheter-based interventions.  Consideration of waiver for continued military flying duties or training require normal or near-normal cardiovascular status, acceptably low risk of aeromedically pertinent events and no significant residua.  Otherwise, the most common congenital disorders that will require aeromedical consideration are atrial septal defect (ASD) and ventricular septal defect (VSD).  Patent ductus arteriosus (PDA) and coarctation of the aorta may also be seen. Hemodynamically significant defects are likely to be detected and corrected during infancy or childhood, especially VSD and PDA.  Other, more complicated congenital disorders will be very unusual because most will be detected in infancy or childhood and, even if corrected, will be unacceptable for entrance into military service.  They may also preclude successful civilian flying activities.

 

ASD

There are three types of ASD, ostium secundum (75%) [failure of septum primum to cover the fossa ovalis], ostium primum (15%) [inadequate development of endocardial cushion, thus fails to close ostium primum], and sinus venosus  (10%) [abnormal embryologic evolution of sinus venous and sinus valves].  ASDs allow shunting of blood flow from the left to right atrium, with resultant right-sided volume overload and enlargement of the right atrium and ventricle.  Presence and time course of symptom development depends on the magnitude of the shunt; shunts greater than a 1.5 pulmonary to systemic flow ratio generally produce significant overload with resultant symptoms, including easy fatigue, dyspnea, and arrhythmias, especially atrial fibrillation.  Straining, coughing, Valsalva, anti-G straining maneuvers or positive pressure breathing may cause the blood flow to reverse, which could serve as conduit for embolic material.  ASDs, even large defects, may not be detected until adulthood.  Prognosis after successful and uncomplicated closure of significant secundum and sinus venosus ASD is normal if accomplished before age 25.  Later closure increases the risk of atrial fibrillation, stroke, and right heart failure.

 

VSD

Hemodynamically significant defects are likely to be detected and corrected during infancy or childhood.  Hemodynamically insignificant VSDs will also likely be detected in infancy or childhood due to the very characteristic murmur, but may not be recommended for closure because of the insignificance of the shunt and the likelihood of spontaneous closure over time.  VSDs repaired before age 2 have a good long-term prognosis.

 

PDA

PDAs classically produce a prominent continuous “machinery” murmur heard at the second left intercostal space.  Small PDAs may escape detection until adolescence or adulthood but are unusual.  In the past even small PDAs were often recommended for surgical or catheter-based closure due to anticipated long-term risks of heart failure, endocarditis and pulmonary hypertension.  Recently, a trend has developed to follow small PDAs without correction/closure.  The proper course of therapy for small PDAs is not yet established in the literature.

 

Coarctation

Coarctation of the aorta results in elevated blood pressure in the upper limbs, with normal or low pressure in the lower limbs.  Associated abnormalities with coarctation include bicuspid aortic valve, congenital aneurysms of circle of Willis, and aortic aneurysms.  Unrepaired coarctation with resting gradient ≥ 20 mm Hg between upper and lower extremities carries an increased risk for progressive left ventricular hypertrophy and subsequent left ventricular dysfunction, persistent systolic hypertension and premature atherosclerotic cerebrovascular and coronary heart disease.  Coarctation of the aorta is usually diagnosed in childhood but up to 20% reportedly are not detected until adolescence or adulthood.  Long-term prognosis is related to age of repair, with the best outcome for correction before age 9.

 

Patent foramen ovale and atrial septal aneurysm

Patent foramen ovale (PFO) and atrial septal aneurysm (ASA) are anatomic anomalies of the interatrial septum.  PFO occurs in 25-30% of the general population.  At that frequency it may be considered a normal variant.  ASA is present in about 1-2% of the general population.  PFO and ASA may be present alone or may occur together.  Asymptomatic PFO and/or ASA are typically incidental findings on an echocardiogram performed for unrelated indications.  These are aeromedically considered normal anatomic variants and therefore are qualifying for all classes of flying duties including initial training.

 

However, PFO and ASA, alone or in combination, have been associated with possible paradoxical embolic events, notably stroke and transient ischemic attack.  Although the relative risk for such an event is increased, the absolute risk is low.  The occurrence of both PFO and ASA are increased in cryptogenic stoke populations.  Regarding stroke, a correctable etiology theoretically would alter the risk of recurrent stroke.  Patent foramen ovale (PFO) is common (autopsy prevalence 29%) and has been associated with stroke.  Previously, the risk for recurrent stroke was thought to decrease to less than 1% after two years if the PFO was surgically closed or occluded with a transcatheter device and no residual shunt exists, based on case series demonstrating effectiveness of closure.  One retrospective study of 45 patients noted 44 (98%) had no recurrence (mean follow-up 5.3 months) while another retrospective noted zero strokes in 185 patients (mean follow-up 19 months).  While many retrospective surgical series are showing success there remains to be demonstrated in prospective randomized controlled studies that percutaneous closure is of benefit in decreasing the incidence of recurrent stroke.  Furthermore, prospective studies of PFO have not shown a difference in stroke recurrence based on the presence or absence of PFO.  In the PFO in Cryptogenic Stroke Study (PICSS), a subpopulation of the Warfarin-Aspirin Recurrent Stroke Study (WARSS), the two-year recurrence incidence was 14.3% with PFO and 12.7% without PFO for the cryptogenic subgroup (as classified by the TOAST criteria) and 14.8% versus 15.4% for the entire population, irrespective of whether they received warfarin or aspirin.  The French PFO/ASA (patent foramen ovale/atrial septal aneurysm) study (age less than 55; mean follow up 37.8 months) noted 4.2% recurrent stroke without PFO, 2.3% with PFO, and 15.2% with PFO and ASA.  Medical treatment did not alter the recurrence rate in either study.  Optimal treatment of PFO and CVA remains to be defined and at this time medical evidence does not definitively demonstrate that closure will lessen the likelihood of recurrence.  Results of the ongoing randomized studies comparing medical therapy to percutaneous closure of a PFO are needed before PFO closure can be recommended.

 

Aeromedical Concerns: Aeromedical concerns are primarily related to the long-term effects of shunting with volume overload and include, for example, atrial and ventricular dilation and dysfunction, tachydysrhythmias, endocarditis or endarteritis.

 

Medical Work-up: The aviator needs to submit a complete history and physical exam to include description of any symptoms, treatment, medications, and activity level.  Also needed is all ECGs and the official report of all echocardiograms along with a CD copy of the images, and copies of reports and tracings/images of any other cardiac tests performed locally for clinical assessment (e.g. treadmill, Holter monitor, cardiac cath, cardiac CT or MRI).  The official cardiology consultation report is also critical as is the operative note if surgery occurred.  If the aviator is military, a medical board report may be indicated prior to consideration for waiver.


Aeromedical Disposition:

 

Air Force: In the US Air Force, congenital heart defects, uncorrected or corrected by surgical or catheter-based procedures, are disqualifying for all flying classes.  Also any history of cardiac surgery or catheter-based therapeutic intervention [including closure of PFO] is disqualifying for all flying classes.  ASD, VSD and PDA successfully corrected by surgery or catheter-based techniques, especially in childhood, may be favorably considered for waiver for all classes of flying duties, as may uncorrected but hemodynamically insignificant ASD and VSD.  Because the appropriate treatment of hemodynamically insignificant PDA is unsettled; uncorrected small PDAs will be considered on a case-by-case basis.  Coarctation of the aorta will also be considered on a case-by-case basis.

 

Army: Generally congenital heart diseases are disqualifying conditions specified in AR 40-501 Standards of Medical Fitness, the exception being corrected PDA which is not disqualifying.  Of primary concern is disease that has long term risks, complications, or impact on duty performance.  The exceptions are those congenital heart disease conditions that can be repaired with resolution of long term risks, complications, and impact on duty performance.

 

ASD is discussed in its own Army APL.  Waivers are usually granted provided complete cardiology work-up is normal and without sequelae, or post-operatively with normal recovery for all classes.  Newly discovered cases of ASD, as well as patent foramen ovale, undergoing repair with a patch are not deployable for 6 months while they undergo anti-platelet therapy.  Cases involving childhood repair require no periodic follow-up, otherwise, a cardiology evaluation is required every 5 years for waiver continuation including a 24-hour Holter monitor and echocardiogram with Doppler flow study.

 

VSD is also discussed in its own APL.  Applicants presenting with VSD are not considered for exception to policy, though applicants with a history of spontaneous or surgical closure and no significant childhood sequelae may be considered on a case-by-case basis.  Newly discovered VSD in a rated aviator, with a history of spontaneous or surgical closure, may be recommended for waiver on a case-by-case basis provided complete recovery and normal cardiology evaluation.

 

Navy: Personnel found to have a Patent Foramen Ovale or hemodynamically stable ASD are PQ for aviation duty. Hemodynamically stable is defined as: (1) asymptomatic, (2) no right ventricular enlargement on echocardiogram, (3) no fixed splitting of S2, (4) normal EKG and (5) normal CXR. Designated aviators with surgically corrected ASD may be considered for waiver. Waivers are not recommended for candidates

INFORMATION REQUIRED:

 

1. Cardiac consultation to include contrast echocardiography is required.

2. NOMI evaluation may be required.

3. There is a risk of atrial dysrhythmias following surgical repair of an ASD.

a. Waiver recommendations for this group must include:

i. Serial Holter monitors (monthly over three months)

ii. Repeat contrast echocardiogram to document closure of the defect.

 

Civilian: Atrial Septal Defect: The majority of cases seen have had surgery when they are young.  The FAA requires the airman to provide a complete current cardiovascular evaluation that preferably includes as many of the pertinent medical records from the surgery as possible.  An echocardiogram is also required.  Should an airman present with a history of a peripheral embolus secondary to an ASD it is expected that the defect is repaired prior to granting medical certification.

 

Ventricular septal defect generally also is discovered historically on the medical history.  Once again attempt to obtain all the pertinent medical records, a current status report from the treating physician and current echocardiogram.

 

Coarctation of the aorta is another historical item that is brought to the attention of the AME when and airman records such a history on the examination.

 

One is expected to follow a similar protocol to clear the airman for medical certification. 

Patent foramen ovale is generally brought to the attention of the FAA when an airman has a stroke and it is discovered. Since one cannot be sure that the PFO caused the stroke, unless it is a large defect, it is expected that the airman is placed on Coumadin or surgical closure is accomplished.  Nevertheless, when an airman has a stroke, they are grounded for one year if there is a possible correctable etiology, such as a PFO.  As mentioned above atrial septal aneurysm is considered a “normal variant” when it is discovered on an echocardiogram usually performed for another reason.  The FAA does accept airmen for all classes when they have had treatment of a PFO.

 

Waiver Experience:

 

Air Force: Query of the AIMWTS database showed 39 congenital heart disease cases and of these cases, 10 were disqualified for an acceptance rate of 74%.  Of the 10 disqualified, three were disqualified for congenital defects not hemodynamically stable (ASD, VSD and coarctation of aorta), one for a PFO, five for TIA/CVA and one for color vision deficiency.

 

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 80 cases of congenital heart disease of all types discovered. Interestingly, most of these records were prior to 1988.  Of the 80 cases, 48 were retained.

 

Navy: Not available at this time.

 

Civilian: In the current PATH CODE system at the FAA they combine all of the congenital heart conditions into one grouping. There are currently issued: 167 first-, 87 second-, and 350 third-class airmen with the congenital heart conditions. 

 

ICD 9 Codes for congenital heart diseases

745.4

Ventricular septal defect

745.5

Patent foramen ovale and ostium secundum atrial septal defect

745.6

Ostium primum atrial septal defect

745.9

Unspecified defect of septal closure

747.0

Patent ductus arteriosus

747.1

Coarctation of aorta

 

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References:

 

Kruyer WB.  Cardiology.  In: Rayman RB, et al eds, Clinical Aviation Medicine, 4th ed.  New York: Graduate Medical Publishing, LLC, 2006; 243-254.

 

Maron BJ, Zipes DP, co-chairs.  36th Bethesda conference: Eligibility recommendations for competitive athletes with cardiovascular abnormalities.  J Am Coll Cardiol.  2005; 45(8):  1326-1333.

 

Strader JR, Jr, Gray GW, Kruyer WB.  Clinical aerospace cardiovascular medicine.  In: Davis JR, et al eds, Fundamentals of Aerospace Medicine, 4th ed.  Philadelphia: Lippincott Williams & Wilkins, 2008; 338-343.

 

Webb GD, Smallhorn JF, Therrien J, Redington AN.  Chapter 61 – Congenital Heart Disease.  In: Libby P, Bonow RO, Mann DL, et al eds, Brauwald’s Heart Disease:  A Textbook of Cardiovascular Medicine, 8th ed.  Philadelphia: Saunders Elsevier, 2008.

 

 

 

Prepared by Drs. William Kruyer and Karen Fox

Date: September 26, 2010