BACKGROUND:Adenosine induced hyperaemic fractional flow reserve (aFFR) is a validated predictor of clinical outcome and part of routine interventional practice. Protocol issues associated with the adenosine infusion limit the use of aFFR in clinical practice. Contrast medium induced hyperaemic FFR (cFFR) is a simpler procedure from a practical standpoint. We compared the two in a real world setting. METHODS:We analysed 76 patients that had both cFFR and aFFR assessment of 100 angiographically indeterminate coronary stenosis. cFFR was performed with intracoronary contrast medium injections (10ml for left coronary lesions and 8ml for right coronary lesions). The diagnostic performance of cFFR was analysed and compared to the gold standard aFFR. RESULTS:Mean cFFR was 0.87 (±0.07) and mean aFFR was 0.84 (±0.08). Bland-Altman analysis revealed a close agreement between cFFR and aFFR (0.035±0.032; 95% CI: -0.028 to 0.098) and good linear correlation (r=0.92, r2=0.86; p<0.0001). Using cFFR cut-off values of ≤0.83 in predicting an aFFR value of ≤0.80 or a cFFR value ≥0.88, predicting an aFFR value of >0.80 yielded a sensitivity of 100%, specificity of 96.1%, positive predictive value of 92.3%, negative predictive value of 100% and diagnostic accuracy of 96%. Only 24% of cFFR values were in the 0.84 to 0.87 range. CONCLUSION:Contrast medium induced hyperaemic FFR as an initial assessment may limit the need for adenosine to when cFFR falls in the 0.84 to 0.87 range. The use of adenosine infusion potentially could have been avoided in the majority of patients in this study.