DETERMINANTS OF SEVERITY OF CORONARY-ARTERY DISEASE IN AUSTRALIAN MENAND WOMEN

Background Factors predicting the occurrence of premature coronary art ery disease (CAD) may not be quantitatively the same as those predicti ng CAD severity, particularly in women, in whom there have been few st udies. Methods and Results To determine factors predictive of severity of CAD and of angina pectoris, we documented atherogenic variables an d the extent of CAD at angiography in 594 consecutively studied men an d women aged 65 years or less. Severity was assessed from the number o f involved major coronary arteries with significant (>50%) luminal obs tructions and from a coronary disease severity score. We related sever ity to quantitative and categorical atherogenic variables and assessed severity of angina (no angina, stable angina, or unstable angina) at the time of study in the same way. There were eight variables independ ently predictive of severity: in descending order of relative importan ce, male gender, diabetes, smoking dose, ratio of total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C), lipoprotein(a) [Lp(a )], age, positive family history, and hypertension. These correctly cl assified 43.3% of patients into no-, one-, two-, and three-vessel dise ase categories and accounted for 25.8% of variance of severity. Among 246 patients not taking lipid-lowering or beta-blocking drugs, these v ariables (in slightly different order) correctly classified 49.2% of p atients and accounted for 36% of the variance. Among men (n=427), seve n significant variables correctly classified 39.3% of patients compare d with 54.5% in women (n=167). For those not taking the above drugs, t hese proportions were 49.4% and 65.4%, respectively. Among the quantit ative variables, total smoking dose was the most predictive independen t variable irrespective of current or ex-smoking habit and was more pr edictive in women than in men; of the lipid variables, high TC/HDL-C ( or low HDL-C) and high Lp(a) were consistently highly predictive for a ll patients and in the subgroup analyses. Patients with unstable angin a had higher coronary severity scores and Lp(a) levels and were more l ikely to have diabetes, hypertension, or a positive family history.Con clusions We conclude that the quantitative variables most relevant to severity of premature CAD and to its prevention in Australian men and women are total amount of lifetime smoking, TC/HDL-C (or HDL-C), and L p(a) and that patients with unstable versus stable angina usually have more severe disease and higher Lp(a).