Objective Fractional flow reserve tests using intracoronary pressure wire are widely used in practice for the assessment of the significance of coronary artery disease. We investigate the meaning of a baseline Pd/Pa during FFR study. Methods and Materials We analyzed the 399 consecutive intracoronary pressure wire study data performed in our hospital using a 'Radi' system for a couple of years. Predictive values of baseline Pd/Pa were calculated by FFR measured after maximal hyperemia. We defined FFR value as positive if FFRhyperemia ��� 0.80 (as in the FAME study) and/or ��� 0.75 (as in the DEFER study). Results A total of 399 studies, 157 (39.3%) were positive when the FAME study criteria was applied and 114 (28.6%) were positive when the DEFER study criteria was applied. A baseline Pd/Pa ��� 0.96 has a 95.9% ( of negative predictive value (NPV) and a 60.2% of positive predictive value (PPV) when a FFRhyperemia ��� 0.80 is defined as a positive (as in the FAME study). And a baseline Pd/Pa ��� 0.96 has a 98.0% of NPV and a 44.2% of PPV when a FFRhyperemia ��� 0.75 is defined as a positive (as in the DEFER study). Conclusion We found that baseline Pd/Pa ��� 0.96 has very high NPV based on either FAME or DEFER criteria. These results would give a important massage that we do not need to induce hyperemia during intracoronary pressure wire study if baseline Pd/Pa is ��� 0.96 in most cases.