Cardiovascular risk assessment

Developed in collaboration with CASA Medical.

Coronary artery disease begins in young adult life. Most major adverse cardiac events (MACE) such as heart attacks or sudden cardiac death occur without prior symptoms. Few, if any, aircrew are involved in accidents and incidents suffer from antecedent symptomatic coronary disease. Most coronary events that occur in younger individuals occur because of the rupture of soft coronary plaques, or superficial erosion of remodelled plaque.

The screening of pilots and controllers with elevated cardiovascular risk is undertaken to detect asymptomatic coronary artery disease of safety relevance. CASA and CAA NZ use screening tools such as PREDICT/AUSCVD to determine if pilots or controllers have elevated cardiovascular risk. Pilots or controllers who have estimated elevated cardiovascular risk are required to see a cardiologist to help determine the extent and risk of any coronary artery disease.

A number of cardiac tests may be required to determine the risks of a major adverse cardiac event occurring that may lead to medical incapacitation. These guidelines allow pilots, controllers, and their treating cardiologists a choice of the further investigations. These are outlined in this guideline. Risk factor management is really important as the risk of future events is greatly reduced by lifestyle modification and the use of preventative medications.

CAA NZ Pilots or controllers with PREDICT 5-year risk estimation ≥10% have a condition that is of safety relevance or aeromedical significance unless coronary disease of safety relevance or aeromedical significance has been excluded.

For pilots or controllers with type 1 diabetes the Steno risk (Steno T1 Risk Engine(external link)) is a more specific risk calculator for type 1 diabetes related coronary artery disease risk. The same 5-year risk estimate of ≥10% applies as the threshold for further cardiology investigations.

This guideline does not apply to:

• Pilots or controllers who have symptomatic coronary artery disease or who have a history of major cardiovascular events
• Pilots or controllers who have evidence of inducible ischaemia or significant coronary artery disease on cardiac testing
• Pilots or controllers who have had revascularisation (PCI or CABG) interventions to treat coronary artery disease

Pilot and controller information

• Pilots and controllers who are asymptomatic and have elevated cardiovascular risk are able to continue flying or operating pending further cardiology investigations
• Pilots and controllers must ground themselves if any of the cardiology investigations are abnormal
• Pilots and controllers must ground themselves and inform their MEs if they are diagnosed with or are suspected of to have coronary artery disease, whether or not they have symptoms

Considerations

Cardiovascular events may lead to medical incapacitation. Thus an estimation of the probability of an applicant suffering a cardiovascular (CV) event is an essential part of the assessment. Such estimation is based on community prevalence of ischaemia.

The General Direction, Timetable for Routine Examinations, prescribes when a formal cardiovascular risk assessment is required to be performed.

GD: Timetable for Routine Examinations [PDF 511 KB]

The General Direction, Examinations Procedures, prescribes how a formal cardiovascular risk assessment should be performed.

The General Direction, Examination Procedures, requires that a 5-year CV risk estimate of 10% or above requires exclusion of cardiac ischaemia.

GD: Examination Procedures [PDF 491 KB]

Note: An applicant with a history of peripheral vascular disease, cerebrovascular accident or cardiovascular disease automatically falls in a high 5-year cardiovascular risk category, i.e. well above 10%.

Other cardiac tests

CAA no longer accepts a stress ECG alone as being sufficient to exclude ischaemia.

A stress echocardiogram or myocardial perfusion scan can be undertaken to more reliably exclude ischaemia. Other reasons to undertake such investigations may be the applicant’s cardiovascular history or a previous equivocal stress ECG. In doubt MEs should contact the CAA.

Aeromedical implications

Effect of aviation on the condition

The flight environment can put considerable stress on the cardiovascular system in general and the heart and coronary arteries in particular.  The sympathetic nervous system response to stressful flight situations, acceleration forces or emergencies will increase heart rate, contractility and blood pressure, increasing oxygen demand of heart muscle and blood flow through a potentially compromised coronary circulation.

• Increased cardiac workload during stressful phases of flight and emergencies
• Cardiovascular responses to G forces
• Mild to moderate hypoxia under normal flight conditions
• Moderate to severe hypoxia with loss of cabin pressure
• Potential sedentary nature of aviation occupations
• Dehydration in hot conditions increasing thrombotic risk

Effect of the condition on aviation

Overt incapacitation in the event of sudden and unheralded MACE, from:

• Distracting pain
• Acute shortness of breath
• Syncope
• Arrhythmia
• Sudden death

Effect of treatment on aviation

Aggressive risk factor modification using medications may be selected for pilots or controllers identified as having significant asymptomatic CAD and/or vulnerable plaques.

• Impaired ‘G’ tolerance secondary to drug therapy eg. certain antihypertensives
• Aeromedically significant side effects eg. muscle pains from lipid lowering drugs

Approach to medical certification

Pilots or controllers with a PREDICT or Steno risk estimation ≥10%/5 years may chose different pathways for further cardiac evaluation. Pilots or controllers are able to discuss these options with their CAA ME or treating cardiologist before selecting which pathway to proceed down. 

The pathways available are:

• Pilots or controllers may decide not to proceed with further cardiac investigations, but this may lead to restricted or denied medical certification
• Functional cardiac testing with stress echocardiography
• Calcium scoring (CACS)
• Coronary CT angiography (CTCA) (+/- FFR as available)
• Invasive coronary angiography (ICA) +/- IFR or FFR

Stress echocardiograms are required to exclude inducible myocardial ischaemia – stress ECGs alone are no longer acceptable. CASA or CAA NZ will review the results from nuclear perfusion scans. Negative nuclear perfusion scan results are acceptable for excluding ischaemia of safety relevance or aeromedical significance. 

Table 1 below outlines the following:

• ME guidance for the interpretation of the results of the initial cardiac investigations for Class 1, 2 and 3.
• Further cardiac investigations if CAA NZ criteria for the initial testing are not met and the next steps regarding medical certification decision making depending upon these results.
• Acceptable CTCA criteria:
  • Left main coronary artery lesion ≤ 50%
  • Other single vessel disease lesion ≤ 70%
  • Aggregate stenoses ≤ 95%

Table 2 outlines the following:

• Timing of routine stress echocardiography and CACS investigations that applies after initial cardiology investigations (CTCA and/or stress echocardiogram) demonstrate the absence of coronary artery disease of aeromedical significance. 

Table 3 outlines the following:

• The timing of follow up routine stress echocardiograms and CACS* depending upon CACS score.

Note: Where investigations demonstrate coronary artery disease of aeromedical significance the application of flexibility to the CAA NZ CAR 67 cardiology standards and individualised risk assessment are required for aeromedical certification.

Risk factor management

This guideline strongly recommends the importance of good risk factor management for all pilots or controllers who have been identified as having elevated cardiovascular risk. Risk factor management strongly influences the risk of future cardiac events that may lead to acute medical incapacitation or loss of medical certification. Medical certification by CAA will take into account risk factor management.

MEs and treating cardiologists are strongly encouraged to discuss current management of risk factors such as:

2023 Australian Heart Foundation Guideline(external link)

NZ Guidelines(external link)

2021 BPAC Statin guidelines(external link)

Table 1 - Matrix of Testing modalities and ME decision outcome

Testing modality if estimated cardiovascular risk ≥ 10% over 5 years	Stress echocardiogram	CACS	CTCA
Acceptable criteria for ME medical certification Medical certification may proceed	Structurally normal heart No evidence of inducible ischaemia LVEF > 50% Exercise induced arrhythmia  Risk factor modification	Score ≤ 100 Score >100 – 399 with a normal stress echo Score 400 – 999 with stress echo and CTCA meeting acceptable criteria Risk factor modification	< 50% left main coronary lesion/ Proximal LAD OR < 70% other SVD lesions OR < 95% aggregate stenoses  Risk factor modification
Criteria not met for ME certification AMC application required Ground from flying or operating pending further evaluation	Any of the following are met: Evidence of inducible ischaemia Exercise induced arrhythmia Unable to complete at least a 9 minute exercise test LVEF < 50%	Score > 100 – 999 Acceptable criteria for Stress echo and/ or CTCA are not meet Score ≥ 1000	≥ 50% left main coronary lesion/ proximal LAD OR ≥70% other SVD lesions OR ≥ 95% aggregate stenoses
Recommended next tests	CTCA ICA +/- IFR or FFR depending upon CTCA result	Score ≥ 1000 - Stress echo AND ICA +/- IFR or FFR	Stress echo AND ICA +/- IFR or FFR

Table 2 - Explanation of testing

Stress echocardiogram*	Stress echocardiogram is requested to assess cardiac function, exclude exercise induced ischaemia or arrhythmia, cardiac structure of potential aeromedical concern due to aviation related factors such as hypoxia, G-forces, elevated heart rate. Normal stress echo means: Stress ECG completed to standards defined by CASA or CAA NZshows no evidence of ischaemic changes or arrhythmia Applicant/participant is asymptomatic, normal LV function and LVEF ≥ 50%, no evidence of inducible ischaemia on stress echocardiogram, no other pathology An abnormal stress echo is of safety relevance or aeromedical significance- proceed to CTCA or IAC
Calcium artery score (CACS)**	CAC score 0 - ≤ 100 – relevant risk factor management discussion with treating health providers recommended. If an individual’s score is ≤ 100 but is ≥75% for age and gender, then it is of safety relevance or aeromedical significance. CAC scores > 100 are of safety relevance or aeromedical significance and proceed to investigations in Table 1 CAC score 101 – 399 – relevant risk factor modification discussion strongly encouraged and will be considered in medical certification CAC score ≥ 400 - 999 - Proceed to CTCA and stress echocardiogram OR ICA alone if any lesion > 50% seen on ICA is assessed by IFR/FFR. Relevant risk factor modification discussion very strongly encouraged and will be considered as part of condition of medical certification CAC score ≥ 1000 - current ability of CTCA to accurately rule out stenoses in heavily calcified vessels is limited. Proceed to ICA and stress echocardiogram.  Any ICA lesion > 50% to be assessed by IFR/FFR. Relevant risk factor modification discussion very strongly encouraged and may be considered as part of condition of medical certification.
CT coronary angiogram (CTCA)	Percentages apply to maximum measured critical stenosis. Stenosis ≥ 50% left main coronary artery or LAD - proceed to further investigations for lesions ≥ 70% outlined in the table above, or aggregate stenoses ≥ 95%. The above criteria are of safety relevance or aeromedical significance and require further investigations such as stress echo, CT-FFR, PCCT, or ICA as outlined in Table 1
CT coronary angiogram FFR (CT-FFR)	CT-FFR < 80% is of safety relevance or aeromedical significance- further investigation such as ICA is an informed clinical decision between the applicant/participant and treating cardiologist.
Invasive coronary angiography (ICA)	The decision to proceed to ICA is an informed clinical decision between the applicant/participant and treating cardiologist. ICA – the presence of any lesions > 50% requires IFR/FFR measurement. IFRs ≤ 0.89 or FFRs < 0.80 identify haemodynamically significant lesions and are of aeromedical significance. The demonstration of such disease requires functional testing (stress echocardiogram) if not already undertaken. Any further evaluation or treatment is an informed clinical decision between the applicant/participant and treating cardiologist.

* These intervals are at the discretion of CAA depending on individual circumstances and risks. These intervals do not apply if an individual becomes symptomatic, following a diagnosis of coronary artery disease, or revascularisation procedures

** Acceptable cardiac testing includes normal stress echocardiogram, CACS <400, or CTCA criteria met

Table 3 - Timing of follow up investigations

	Class 1 and 3 Currency period in asymptomatic applicant/participant with normal follow up cardiac investigations and inducible ischaemia excluded	Class 2
CACS 0-100 or  Negative stress echo or Acceptable CTCA	Repeat CACs every 6 years. 2 yearly stress echocardiogram  Repeat CTCA as recommended by cardiologist. Indicated risk factor management is strongly recommended.	Repeat CACs every 6 years Stress echocardiogram 3 yearly. Repeat CTCA as recommended by cardiologist. Indicated risk factor management is strongly recommended.
CACS > 100– 399 With negative stress echocardiogram or An acceptable CTCA	Annual stress echocardiogram. Repeat CACS every 6 years. Repeat CTCA as recommended by cardiologist. Risk factor management required. If risk factor management is not optimal the frequency of stress echocardiograms may be reduced.	Stress echocardiogram 2 yearly. Repeat CACS every 6 years. Repeat CTCA as recommended by cardiologist. Risk factor management required. If risk factor management is not optimal the frequency of stress echocardiograms may be reduced.
CACS ≥ 400 Stress echo and CTCA+/-FFR  (ICA at cardiology discretion); if all clear	Annual stress echocardiogram. Repeat CTCA as recommended by cardiologist. Risk factor management us required and will be considered as part of condition of medical certification.	Annual stress echocardiogram. Repeat CTCA as recommended by cardiologist. Risk factor management required and will be considered as part of condition of medical certification.

These intervals are at the discretion of CAA, depending on individual circumstances and risks.

These intervals do not apply if an individual becomes symptomatic, following a diagnosis of coronary artery disease, or revascularisation procedures.

Risk assessment protocol - information required

If there is elevated cardiovascular risk, CAA require a report from a cardiologist. The report should detail:

• Confirmed absence of myocardial ischaemia or significant coronary artery atheroma OR
• If present, confirmed diagnosis and extent of any coronary atheroma identified, noting any functional ischaemia if present.
• Clinical status
  • Symptoms, if any, such as pain, palpitations, dizziness, breathlessness
• Investigations conducted (which may include):
  • Coronary artery calcium score
  • CT coronary angiogram
  • Results of a stress echocardiogram with ejection fraction
  • Angiographic findings (if performed)
  • Surgical report (if performed)
• Investigations required:
  • Serum lipids, glucose, HbA1c
  • Stress echocardiogram, CACS or CTCA as indicated in these guidelines
• Management (if applicable)
  • Control of cardiac risk factors
  • Treatment or interventions (note any residual stenoses)
  • Side-effects of medications
• Proposed monitoring and follow-up plan
• Prognosis including estimated annualised percentage risk of MACE and incapacitation from rupture of vulnerable plaques

ME aeromedical decision guide

If ALL the criteria in the table below are met the ME may issue the controller or the pilot a medical certificate. Evidence supporting the ME’s decision (for example reports and results) must be sent to CAA. 

ME must confirm	Tick
No history of coronary artery or other cardiovascular disease
No symptoms of coronary artery disease or cardiovascular disease
Investigations have excluded inducible ischaemia or significant anatomic disease
Investigations have excluded other significant cardiac disease
ME has discussed and reviewed risk factor modification with pilot or controller if indicated
ME considers safe to certify

An AMC referral to CAA NZ Aviation Medicine teams is required if a pilot’s or controller’s condition does not meet all the above criteria and they consent to their condition being considered under flexibility to the CAR 67 rules.

ME letters

Cardiovascular risk asymptomatic pilots and controllers medical certificate letter [DOCX 22 KB]