Their rationale is that a) no method short of the CT-scan-approach can identify many of the millions of Americans who have active CAD and thus who are at increased risk for heart attack, and b) identifying them can lead to aggressive therapy that can slow, halt or reverse the progression of their CAD and save their lives.
Critics of this "aggressive screening" approach point out that no large, prospective, randomized trial has clearly demonstrated that aggressively treating these individuals will significantly improve their outcomes. (While this is true, a meta-analysis that appeared in a recent issue of the Journal of the American College of Cardiology strongly supports the notion that patients with underlying CAD have significantly improved outcomes with intensive statin therapy.)
Should you be screened for CAD, and if so, which test should you get?
For anyone who has actual symptoms suggestive of CAD - chest discomfort, dizziness, palpitations, etc., - it is probably best to first rule out critical blockages, since symptomatic CAD is usually associated with blockages. For such individuals, the "traditional" approach usually answers the immediate question (i.e., the one about blockages) quickly and definitively.
On the other hand, if you have no symptoms but, by virtue of your risk factors, are worried about the possibility of CAD, it makes sense to have screening with either EBCT or multislice CT scans - as long as the following condition is true: if the test is positive, both you and your doctor will institute aggressive therapy including risk factor modification. It has been demonstrated, unfortunately, that many patients fail to alter their lifestyles even if they are informed they definitely have active coronary artery disease. And many doctors are unwilling to institute aggressive medical therapy in patients with positive CT scans, especially if the patients themselves are unwilling to modify their own risk factors.
If you know ahead of time you're not going to lose weight, exercise, stop smoking, alter your diet, etc., and if your doctor is not going to treat you, then don't waste your money or expose yourself to all the radiation you'll receive with an EBCT or multislice CT scan, just to prove you have a disease you're not going to treat. Just go ahead and keep doing what your doing, and if you're lucky enough that your first symptom of CAD is something other than sudden death (which it is 30 - 40% of the time), you can take the traditional approach to CAD when the time comes. The outcome with this plan is often very bad, but if it's any consolation to you, most "traditional" cardiologists will support your decision.
Sources:
Naghavi M, Falk E, Hecht HS, et al. From vulnerable plaque to vulnerable patient: Part III. Introducing a new paradigm for the prevention of heart attack; identification and treatment of the asymptomatic vulnerable patient. Screening for Heart Attack Prevention And Education (SHAPE) task force report. Executive Summary. American Journal of Cardiology2006;DOI:10.1016.
