TP 13312

•	Foreword
•	Section 1
•	Section 2
•	Neurology
•	Cardiovascular
•	Diabetes
•	Asthma
•	Other Policies
•	Contacts
•	Alternate Formats

Chapter 1: Acute Ischemic Syndromes

• Chest Pain
• Following an Acute Ischemic Syndrome Including Myocardial Infraction
• Following Revascularization
• Risk Factors for Ischemic Heart Disease 
• Smoking
• Increased Serum Cholesterol Levels
• High Blood Pressure
• Therapeutic Considerations
• Multiple Risk Factors
• Comments on Screening

Chest Pain

Chest pain, regardless whether typical or atypical for ischemic heart disease, precludes medical certification insofar as it indicates an elevated probability of significant coronary artery disease and an increased risk of an incapacitating cardiac event. 

An applicant may be considered fit if diagnostic testing indicates that the chest pain is not due to myocardial ischemia. The initial assessment including a review of the symptom history must be made without the effect of anti-ischemic medications that could possibly mask adverse findings. If coronary arteriography reveals normal coronary arteries, coronary vasospasm should be excluded. The presence of continuing symptoms of chest pain in the absence of ischemia is not disqualifying per se; however, such symptoms must not be incapacitating in any way.

Following an Acute Ischemic Syndrome Including Myocardial Infarction

An acute ischemic syndrome is initially incompatible with medical certification. However, disqualification is not necessarily permanent, and medical certification may be considered 6 months after the event (a decision at 6 months must be based on requisite assessments completed no sooner than 5 months after discharge from hospital) provided the
following criteria are met: 

• The result of an exercise test to a minimum effort of 8.5 METS (end of Stage 3) using the Bruce protocol or equivalent places the individual at low (<2%) risk of a significant cardiovascular event over the following 12 months. Medications
  need not be stopped for the test. If a perfusion exercise test is used, there should be no significant reversible defect and no large fixed deficit as explained in the next point. 
• The left ventricular ejection fraction as a measure of left ventricular function using echocardiography or gated radionuclide scintigraphy, is better than 50% at rest and does not show a decrease of more than 5% with satisfactory
  exertion (i.e. 85% predicted maximum heart rate or > 8 METS). A threshold ejection fraction of 45% applies with the use of SPECT (single proton emission computerized tomography) scanning. 
• With a satisfactory ejection fraction as described above, Holter-monitoring is not required. For an ejection fraction between 40% and 50%, restricted medical certification may be considered after review of a 24 hour Holtermonitor. This should reveal no more than 3 ventricular ectopic beats per hour in the absence of antiarrhythmic medication, with no more than 3 consecutive beats and a cycle length that is not less that 500 msec.
• Major modifiable risk factors (see below ) for recurrence of infarction are controlled, and the applicant is a non-smoker. 

A follow-up assessment a year after the infarction and then annually should include a thorough history, physical examination, rest and exercise electrocardiography and a review of modifiable risk factors. If there is no clinical deterioration after 2 years, the treadmill exercise test can be done every 2 years until the applicant is 50 years of age and subsequently the possible need for yearly testing should be considered.

These criteria apply regardless of whether the applicant was treated for acute thrombosis e.g., with a thrombolytic drug, percutaneous coronary intervention (PCI) or bypass surgery or the infarction occurred in the presence of only mild to
moderate atheromatous disease as demonstrated by arteriography.

Following Revascularization

An applicant who has been treated for coronary artery disease by revascularization including bypass surgery, angioplasty with or without stenting, directional atherectomy etc., can be considered for medical certification after an interval of 6 months, provided the following criteria are met:

• The result of an exercise test to a minimum effort of 8.5 METS (end of Stage 3) using the Bruce protocol or equivalent places the individual at low (<2%) risk of a significant cardiovascular event over the following 12 months.
• Patency of the revascularized artery is maintained with no evidence of reversible ischemia on rest and exercise perfusion imaging. 
• Major modifiable risk factors (see below) are controlled and the applicant is a non-smoker. 
• Left ventricular function following bypass surgery is satisfactory.

A follow-up assessment a year after the revascularization and then annually should include a thorough history, physical examination, rest and exercise electrocardiography and a review of modifiable risk factors. If there is no clinical deterioration after 2 years, the treadmill exercise test can be done every 2 years until the applicant is 50 years of age and subsequently the possible need for yearly testing should be considered.

Risk Factors for Ischemic Heart Disease

The following are major modifiable risk factors for ischemic heart disease. While many of them may have impressively large relative risks, their absolute risk, particularly for sudden incapacitation, is low. Concern about these risk factors is greater in applicants with known ischemic heart disease where the absolute risk is greater. The presence of major modifiable risk factors should be a concern in any applicant and preventive measures are strongly advised.

Smoking

Prohibition of smoking in the cockpit should be the norm for all flights of any duration. An applicant with known ischemic heart disease who continues to smoke should be assessed as “unfit”. 

Increased serum cholesterol levels 

All applicants are encouraged to be aware of their serum cholesterol level and to maintain a normal level. Target levels depend on the level of risk as outlined in the Canadian Working Group Guidelines. Table 1. Total risk can be assessed on the basis of risk points for age, total and HDL cholesterol, systolic blood pressure and smoking status in the absence of existing coronary heart disease or diabetes. Table 2. The presence of either condition places the individual in a very high risk level. All currently approved medications for lipid lowering are compatible with flying.

Table 1 - Target Lipid Levels

Table 2 - 10–Year Absolute Risk of CVD Event

* in individuals who have not had a prior CVD event.

High Blood Pressure

The approach to the diagnosis of hypertension follows that of the Canadian Hypertension Recommendations Working Group. In licence holders with accurately measured blood pressure levels between 140 and 180 mmHg systolic and/or 90 and 105 mmHg diastolic, at least four further visits over 6 months are required to diagnose hypertension. However, in the presence of target organ damage, including coronary artery disease, LVH, LV systolic dysfunction, stroke, aortic and peripheral arterial disease, hypertensive nephropathy (creatinine clearance < 1 mL/s) or retinopathy or asymptomatic atheroscelrosis, a diagnosis of hypertension can be made at the third visit. The search for target organ damage can begin as early as the second visit. 

If pressures remain at or above 160 mmHg systolic or 100 mmHg diastolic, it is strongly recommended that drug treatment be initiated. It should also be considered when the diastolic pressure is between 90 and 100 mmHg. Medical certification can be granted when treatment has been successful in reducing the blood pressure below 160 mmHg systolic and below 100 mmHg diastolic, however the goal of blood pressure control is less than 140/90 mmHg in most
individuals including the elderly and to less than 130/80 mmHg in those with diabetes or renal dysfunction. On any visit, a blood pressure level of 180 mmHg or more systolic or 105 mmHg or more diastolic precludes medical certification.

Therapeutic Considerations

Recommended initial treatment now includes diuretics, long acting dihydropiridine calcium channel blockers and ACE inhibitors. Beta-blockers are included for those under 60 years of age while alpha-blockers are not recommended as first-line therapy. In licence holders, the major challenges with treatment are to minimize postural hypotension, the risks of arrhythmias and adverse CNS effects.  

Preferred drugs include:

1. ß-blockers: hydrophilic drugs are preferred (e.g. atenolol, nadolol, timolol).
2. Calcium channel antagonists: long-acting dihydropyridines are preferred (e.g. amlodipine, felodipine, nifedipine XL).
3. ACE-inhibitors: long-acting ACE-inhibitors are preferred such as ramipril, cilazapril, fosinopril, lisinopril, quinapril, etc.
4. Low dose diuretics: hydrochlorothiazide (< 25 mg/day) or potassium/ magnesium sparing diuretics such as amiloride and spironolactone should be used

Acceptable drugs include:

1. ATII receptor blockers: candesartan, irbesartan, losartan, and others are similar to ACE inhibitors in their hemodynamic action. They can be used singly or in combination. As with ACE inhibitors, ATII receptor blockers are acceptable in pilots who have been on one of these medications for a month or more without any adverse effects.

Drugs that are not permitted include:

1. Sympatholytics: guanethidine, most a blockers
2. High dose kaliuretic diuretics (> 25 mg hydrochlorothiazide or equivalent).
3. Clonidine and methyldopa (because of a risk of rebound hypertension if these medications are inadvertantly not taken).

Combination treatment, eg a low dose diuretic with an ACE inhibitor may be allowed particularly as small doses of medications in combination may lead to fewer adverse effects than larger doses of single agents.

Multiple Risk Factors

Coronary atherosclerosis is a multifactorial disease, the risk of early onset increasing with the number of risk factors present. Therefore in applicants the assessment of risk must weigh appropriately the contribution of the various factors present. The cumulative risk conferred by the presence of more than one risk factor, even at levels only moderately above normal, can exceed that conferred by the presence of one major risk factor alone. The presence of only moderately elevated levels of risk when any risk factor is assessed alone should not lead to a false sense of security on the part of the physician or the applicant.

If the 10 year risk score is 20% or greater (9 risk points for men and 15 risk points for women, Table 2) or if diabetes or left ventricular hypertrophy are present, then a cardiovascular assessment including an exercise treadmill test should be carried out. Additional tests will depend on the risk factor profile. If abnormalities are found, resulting in an average annual mortality risk of 1% or more, assuming an additional 1% risk of an incapacitating nonfatal event, then a licence holder is considered unfit. Even if the response to exercise testing is normal, appropriate therapy to modify risk factors should be initiated.

Comments on Screening

Screening of the aircrew and air traffic controller population to identify cardiovascular disease before sudden incapacitation is a problematic and controversial undertaking. On the one hand, the pilot may feel harassed and unfairly burdened by the inconvenience and expense of screening tests. On the other hand, almost every accident involving sudden incapacitation that is suggestive of or attributed to a cardiovascular cause brings impassioned public appeals for more rigorous screening. It is beyond the scope of these guidelines to present the results of analyses that indicate the costs and problems of widespread routine screening. Nevertheless, a rational policy toward screening can be adopted to provide optimal, though never total, prevention of cardiac incapacitation.

The current routine medical examination is intended to ensure that only medically safe aircrew are allowed to fly. This is a shared responsibility with the onus on the applicant to report any symptoms and on the physician to conduct a careful and thorough examination.

A resting electrocardiogram may show no abnormalities even in the presence of severe coronary artery disease; in fact, this may be true in up to 50% of people with advanced coronary artery disease. Since the prevalence of ischemic heart disease increases with age, the utility of routine electrocardiography improves after age 50 and with the presence of major risk factors for ischemic heart disease. The current recommendations for routine electrocardiographic testing which stratify the frequency of testing by age are considered adequate.

Compared with a resting electrocardiogram, exercise electrocardiography increases the likelihood of detection of coronary artery disease. Widespread introduction of routine exercise testing is not advisable because of concerns about inaccuracies in the interpretation of test results as well as adverse economic and psychosocial consequences. The predictive value of a test result i.e. whether a test result is truly positive or truly negative is influenced by the clinical characteristics of the person undergoing such testing. Routine screening of all applicants by a treadmill exercise test will yield falsepositive results more often than true-positive results. On the other hand, the number of true-positive results is increased significantly if such testing is applied only to those who are more likely to have coronary artery disease, such as those with symptoms of angina, those for whom major risk factors are present and those in older age groups. Such a targeted approach will not impose a major burden and will encourage adoption and maintenance of a heart healthy lifestyle.