Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 53 5 2015 05 15 266 269 EN Mohammad Hasan Namazi Department of Cardiology, Cardiovascular Research center, Shahid Beheshti Univercity of Medical Sciences, Tehran, Iran. Morteza Safi Department of Cardiology, Cardiovascular Research center, Shahid Beheshti Univercity of Medical Sciences, Tehran, Iran. Hosein Vakili Department of Cardiology, Cardiovascular Research center, Shahid Beheshti Univercity of Medical Sciences, Tehran, Iran Habibollah Saadat Department of Cardiology, Cardiovascular Research center, Shahid Beheshti Univercity of Medical Sciences, Tehran, Iran. Saeed Alipour Department of Cardiology, Cardiovascular Research center, Shahid Beheshti Univercity of Medical Sciences, Tehran, Iran. Abdulkarim Alhuthaifi Department of Cardiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Shamseddin Pedari Department of Cardiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Mohammad Amin Abbasi Department of Internal Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, 2015 10 11 Myocardial fractional flow reserve (FFR) is a new index of the functional significance of intermediate coronary stenoses that is calculated from pressure measurements made during coronary arteriography. The aim of this study was to evaluate the correlation between non-hyperemic coronary pressure dicrotic notch and fractional flow reserve (FFR). A consecutive of 114 patients (73 men and 41 women) was enrolled in this study. Data were shown as means ± SD. Statistical analyses were performed with SPSS software. The statistical significance of differences was determined by chi-square analysis with Yates correction. Significance was defined as P< 0.05. Positive dicrortic notch was observed in 97 patients (85%). Significant association was detected between coronary pressure notch (dicrotic notch), and FFR as loss of the dicrotic notch was detected in 93.8% (15/16) of patients with FFR less than 0.75 (P=0.001). Upon ROC curve, a cutoff FFR value of approximately 0.75 demonstrated sensivity and specifity of 93.8% and 98%, respectively for loss of the dicrotic notch. The positive predictive value for loss of the dicrotic notch was 88.2%. Our study demonstrated loss of non-hyperemic coronary pressure diacrotic notch correlates significantly with FFR and may predict an FFR < 0.75 with high accuracy. In patients with functionally significant coronary stenosis, loss of non-hyperemic diacrotic notch appears to be a useful index of the functional severity of the stenoses and the need for coronary revascularization. https://acta.tums.ac.ir/index.php/acta/article/view/4894 https://acta.tums.ac.ir/index.php/acta/article/download/4894/4454