The Influence of Low and Iso-osmolar Contrast Media on Diagnostic Performance of Contrast Fractional Flow Reserve Measurement

For fractional flow reserve measurement, contrast media can be used as an alterna- tive for adenosine. However, contrast media with different physical characteristics (e.g., osmo- lality and viscosity) may have different effects on hyperemia. This study aimed to determine if the diagnostic accuracy of contrast fractional flow reserve was influenced by 2 commonly used contrast media (Visipaque and Ultravist).In this diagnostic study, candidates for coronary angiography with intermediate cor- onary lesion were enrolled and randomized to receive either an iso-osmolar contrast media (Visipaque) or a low osmolar contrast media (Ultravist) for fractional flow reserve measure- ment. The gold standard was fractional flow reserve measured by adenosine fractional flow reserve. Then cFFR and adenosine fractional flow reserve were compared between the groups, and the diagnostic values of both contrasts were calculated. Finally, the cut-point for diagnos- ing adenosine fractional flow reserve ≤ 0.8 was calculated for cFFR in both groups.In this study, 46 patients were studied (24 patients received Ultravist and 22 patients received Visipaque). There was no significant difference between the groups in adenosine frac- tional flow reserve. Also, the mean cFFR was not different from the mean adenosine fractional flow reserve in both groups. There was a strong correlation between cFFR and adenosine frac- tional flow reserve for each of the contrasts (r = 0.937 for Ultravist and r = 0.927 for Visipaque). Both contrasts had high specificity to diagnose fractional flow reserve ≤ 0.8 (specificity = 1), and the sensitivities of cFFR for Ultravist and Visipaque were 83.3% and 94.7%. The cut-point to predict adenosine fractional flow reserve ≤ 0.80 was 0.845 for Ultravist and 0.835 for Visipaque.Both iso-osmolar or low osmolar contrast media have an acceptable diagnostic accuracy in measuring cFFR.