Background & Objectives: Usually, among the candidate patients for cardiac valve's surgery, the coronary artery angiography is performed according to their age and gender. By this research, the prevalence of coronary artery disease is studied in addition we have tried to consider the risk - factors of coronary artery disease to predict the probability of coronary artery disease among them.

  Methods: we studied prospectively a population of 320 patients (144 male and 176 female) who were candidate to cardiac valve's surgery and underwent preoperative angiography in the cath - Lab of Imam Khomeini hospital in Tehran, from April - 1999 to October - 2003.

  Result: There was aortic valvulopathy in 131 patients, mitral in 90 and combined Mitro-aortic in 99. Angina was present in 35% and coronary artery disease risk factors in 27.8% of patients. The prevalence of coronary artery disease was 13.1 %. The prevalence of coronary artery disease in patients with angina was significantly higher (22.3% versus 8.2% in patients without angina). In addition the prevalence of coronary artery disease was significantly higher in patients with coronary artery disease risk factors (22.5% versus 9.5% in patients without risk factors). Three predictive factors of CAD in these patients were age, presence of angina pectoris and presence of CAD risk Factors. The prevalence of CAD in patients who have neither angina nor risk factors was 4.6%. In this group of patients no male under 60 years old and only 3.5% of female patients under 65 years old had coronary artery disease.

  Conclusion: The study showed that due to the low prevalence of coronary artery disease in patients with none of the coronary risk factors or without angina, we can avoid preoperative coronary angiography in males under 60 years old and females under 65 years old who have neither angina nor risk factors of CAD.