Fifty percent of patients with coronary artery disease do not have any of the conventional risk factors.

Prinzmetal's variant angina, primarily a vasospastic disease, is a glaring example of the gaps in our knowledge regarding the etiology of coronary heart disease. Half of all patients with coronary heart disease do not have any of the established coronary risk factors. Prinzmetal's variant angina, syndrome X, coronary embolization, and congenital coronary anomalies, are a few examples of conditions that may not be associated with established risk factors. New risk factors that are emerging in an attempt to establish an etiology in this group of patients are homocysteine plasma fibrinogen, estrogen-deficiency lipoprotein (a), C-reactive protein, Chlamydia pneumoniae, factor VII endogenous tissue plasminogen, and endogenous plasminogen activator/inhibitor type I. The battle against cardiovascular disease continues!