ASYMPTOMATIC CORONARY-ARTERY DISEASE DETECTION - UPDATE 1996 - A SCREENING PROTOCOL USING 16-LEAD HIGH-RESOLUTION ECG, ULTRAFAST CT, EXERCISE TESTING, AND RADIONUCLEAR IMAGING

The authors have proposed a new four-step screening algorithm to detec t asymptomatic coronary artery disease (CAD) in flight school candidat es, cadets, and rated flyers of the Unites Slates Air Force (USAF). In step 1, the USAF Armstrong Laboratory (USAF/AL) risk profile and impr oved 16-lead high-resolution electrocardiogram/vectorcardiogram will b e recorded at baseline. On routine follow-up evaluations, quantitative serial comparisons will be performed by the method of Kornreich. In s tep 2, beginning with flight school candidates and cadets, all three g roups will be studied by the ultrafast computed tomograph (CT) protoco l. Those candidates positive for coronary calcium will be studied by c oronary angiography and ventriculography, and their eligibility for co ntinued rated flight status will be determined by present criteria. Ln step 3, those candidates negative for coronary calcium by ultrafast C T will then be screened by the newly defined and improved high-sensiti vity treadmill exercise test criteria. In step 4, candidates with a po sitive treadmill exercise test result, or who are also found in the up per quintile of the USAF/AL risk profile, wild also have exercise nucl ear wall motion studies and perfusion scans. Lf these are abnormal and suggestive of myocardial ischemia, this subset will also be studied b y heart catheterization and coronary angiography, and their eligibilit y for continued rated flight status will be determined by present crit eria. The incidence of coronary calcium/no calcium for each degree of stenosis in the 6,000 flyers in each quintile was used to develop the following projections: (1) chat more than 3 of 4 rated flyers with uns uspected CAD, and (2) more than 9 of 10 with severe flow-limiting CAD can be identified by these upgraded screening procedures. Evidence is herein presented that these enhancements will result in a major (5-8-f old) increase in case finding of this disease. Based on the estimate o f four lost high-performance aircrafts per year from sudden incapacita tion of the pilot due to CAD, when this four-step screen is fully oper ational, it can be expected to reduce the $80 million annual losses to the United States government from CAD by 85%, a savings of $68 millio n per year.