This interesting study by Gary Gray et al was published in the British Medical Journal in January 2019. It looked at providing Cardiac Screening Guidelines for Asymptomatic Individuals and Air Crew in particular.
Coronary events remain a major cause of sudden incapacitation, including death, in both the general population and among aviation personnel, and are an ongoing threat to flight safety and operations. The presentation is often unheralded, especially in younger adults, and is often due to rupture of a previously non-obstructive and asymptomatic coronary atheromatous plaque. The challenge for medical practitioners is to identify individuals at increased risk for such events.
This paper presented the NATO Cardiology Working Group (HFM 251) consensus approach for screening and investigation of aircrew for asymptomatic coronary disease.
Their recommendation was to screen all aircrew from the age of forty and initially calculate the Coronary Artery Disease Risk using a risk calculator such as Framingham Risk Score. This scoring system provides an estimate of an individual cardiac risk based on factors such as age, cholesterol, smoking and blood pressure.
All individual Aircrew identified as being at increased cardiovascular risk based on initial screening should then undergo enhanced screening. Enhanced screening includes additional testing with Coronary Artery Calcium Scoring alone, or combined with CT Coronary Artery Angiography.
Calcium Score (extent of calcified plaque in coronary arteries) quantifies cardiac risk as it reflects overall coronary plaque burden. Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens, narrows your arteries and causes heart attacks. The higher the Calcium Score, the more likely an individual is to have separate, non-calcified plaque that is vulnerable to rupture and cause a sudden heart attack.
Therefore, for aircrew identified at higher risk based on traditional risk factor estimation, Calcium Score provides a better estimation of future risk and is the preferred modality for enhanced screening alone or combined with a CT Coronary Artery Angiography. For space flight participants travelling to the International Space Station (and International Space Station (ISS) crew members), Coronary Artery Calcium Score is a required primary screening test.
Not all plaque however is calcified, and plaque rupture events may occur in individuals with only non-calcified plaque and low Calcium score.
CT Coronary Angiography provides additional information about the number, extent and location of narrowing in the coronary arteries. It additionally has the advantage of being able to both image and characterise plaque (into calcified or non-calcified). This allows identification of plaque disease that may be present in significant quantities even with very low/no coronary calcium and thus identify individuals with low coronary calcium scores who are nevertheless at increased risk for coronary events.
We believe that the science behind these guidelines for screening of asymptomatic pilots and air crew is applicable to any health-conscious person who wants to assess and improve his/her cardiac risk.