The naturally occurring antithrombins, primarily anti- thrombin-III, are key modulators of coagulation and appear to protect against increased fibrin deposition. The role of antithrombin-III with respect to atherogenesis and myocardial infarction remains unclear; however, it has been reported that antithrombin-III levels are decreased in many individuals with coronary artery disease and in those at high risk for coronary artery occlusion. However, the several reports available do not agree and remain inconclusive. To better define the role of antithrombins in coronary artery disease antithrombin-III levels were determined in 86 individuals undergoing coronary artery angiography. Angiography was performed by the brachial or femoral route and evaluation was by cineradiographic technique using standard RAO and LAO projections. Patients were categorized as 0=no coronary artery disease, Class I = 50% stenosis of 1 or 2 vessels, Class II = 75% stenosis of 1 or 2 vessels, Class III = 75% stenosis of 3 vessels, and Class IV = stenosis of
3 vessels and abnormal left ventricular function. Samples for AT-III determinations were drawn at both the initiation and cessation of the procedure. Results of these determinations reveal that the majority of patients with documented coronary artery disease by angiographic studies have normal antithrombin-III levels. Additionally, there was found to be no correlation between antithrombin-III levels and severity of coronary artery disease. The only finding was that during the angiographic procedure antithrombin-III levels tend to decrease, confirming the work of others that angiographic dyes in general may alter hemostasis. The results of this study would suggest that plasma antithrombin-III levels are of no particular significance in determining the presence, absence, or severity of coronary artery disease.
Cardiac syncope due to transient coronary artery occlusion: the role of percutaneous angioplasty.