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Contrast FFR plus intracoronary injection of nitroglycerine accurately predicts FFR for coronary stenosis functional assessment.

BACKGROUND
FFR is the "gold standard" for assessing the physiological significance of coronary disease. In the last decade, several alternative adenosine-free indexes have been proposed in order to facilitate the dissemination of the functional evaluation of coronary stenosis. Our aim was to investigate whether radiographic contrast plus intracoronary nitroglycerin (cFFR-NTG) can predict functional assessment of coronary stenosis offering superior diagnostic agreement with FFR compared to non-hyperemic indexes and contrast mediated FFR (cFFR).


METHODS
329 lesions evaluated with pressure wire in 266 patients were prospectively included in this multicenter study.


RESULTS
The ROC curves for cFFR-NTG using a FFR≤0.80 showed a higher accuracy in predicting FFR (AUC 0.97) than resting Pd/Pa (AUC 0.90, p<0.01) and cFFR (AUC 0.93.5, p<0.01). A significant (p<0.01) strong correlation was found between FFR and the four analyzed indexes: Pd/Pa(r=0.78); iFR/RFR (r=0.73); cFFR(r=0.89) and cFFR-NTG(r=0.93). cFFR-NTG showed the closest agreement at Bland-Altman analysis. The cFFR-NTG cut off value >0.84 showed the highest negative predictive value (88%), specificity (91%), sensitivity (94%) and accuracy (92%) of the studied indexes.


CONCLUSIONS
Submaximal hyperemic adenosine-free indexes are an efficient alternative to adenosine for the physiological assessment of epicardial coronary disease. The most accurate index in predicting the functional significance of coronary stenosis using FFR as reference was cFFRNTG.