Assessing the physiologic significance of coronary obstructions in patients: Importance of diffuse undetected atherosclerosis

Abstract

T HE HALLMARK OF coronary atherosclerosis is an apparently localized obstruction of a conduit coronary vessel. Until Sones introduced the technique of selective coronary angiography,’ for the most part the anatomy of these localized coronary obstructions could only be defined at postmortem. The ability to anatomically define coronary obstructions with a broadly applicable clinical technique has vastly altered our approach to the diagnosis and treatment of coronary atherosclerosis. Each new step forward, however, immediately brings forth new questions. Thus, coronary angiography has forced physicians to develop approaches of defining the physiologic significance of coronary lesions that can be demonstrated angiographically. Accurately assessing the physiologic significance of coronary obstructive lesions is critical to clinical decision making. The need for coronary bypass surgery, percutaneous transluminal coronary angioplasty, the adequacy of prior bypass surgery and percutaneous transluminal coronary angioplasty, and the validation of noninvasive approaches to the diagnosis of coronary disease all critically depend on assessing the physiological significance of coronary obstructive lesions. For more than two decades, the physiological significance of coronary obstructions detected by coronary angiography has been assessed primarily by visual estimates of percent stenosis. To a lesser extent clinicians have used other aspects of the patients’ clinical presentation including symptoms and results of various noninvasive procedures. Because percent stenosis remains the gold standard today in more than 99% of hospitals that perform coronary angiography, this review will examine the advantages and disadvantages of this approach.