Purpose : The cold pressor test(CPT) has been used to detect vasospastic angina, but its sensitivity for predicting vasospasm was low. The aim of this study was to test whether the estimation of coronary flow reserve capacity in left anterior descening coronary artery using transthoracic Doppler echocardiography(TTE) and CPT can predict coronary artery spasm. Methods: The provocation test of coronary artery spasm using acetylcholine (50 and 80 關g) was performed in 65 subjects(52짹10 yrs, M:F=41:24) with chest pain and normal coronary angiogram. Before and during CPT, the peak(PDV) and mean diastolic flow velocity(MDV) of distal left anterior descending coronary artery using high frequency TTE were estimated(Figure) and ECG, blood pressure and symptoms were monitored every minute. CPT%PDV and CPT%MDV were defined as % change of PDV and MDV during CPT, respectively. The subjects were divided into two groups [(Spasm+group, 31) and (Spasm-group, 34)] and compared. Results : 1.CPT%PDV was 52.75짹24 % in Spasm-group and 4.99짹23.62 % in Spasm+group(p<0.001). 2.CPT%MDV was 50.22짹27.83% in Spasm-group and 6.83짹23.81 in Spasm+group (p<0.001). 3.CPT%PDV<31.1% had sensitivity of 93.5% and specificity of 90 % for predicting coronary artery spasm (95% CI:0.939-0.979, p<0.001). 4.CPT%MDV<30.55% had sensitivity of 90 % and specificity of 76.5 % for predicting coronary artery spasm(95% CI:0.884-0.950,p<0.001). Conclusion : Estimation of coronary flow reserve capacity using TTE and CPT is a promising noninvasive test for predicting variant angina.