Efficacy and Safety of High-Dose Intracoronary Adenosine Injection in Fractional Flow Reserve Assessment

Background: The recommended dosage of intracoronary adenosine in fractional flow reserve (FFR) assessment is controversial. High-dose adenosine may overcome the biological variability of adenosine response in hyperemia. Objectives: We aimed to test the efficacy and safety of a high-dose escalation protocol at our institute. Methods: Using the adenosine dose escalation protocol, the percentages of FFR ≤ 0.75 and 0.80 after high-dose escalation were compared with those at conventional doses. The chi-squared test was used to evaluate the accuracy of FFR values with the tested doses by comparing them with the results of a non-invasive pretest. Results: A total of 87 patients (130 vessels) were included, and protocol adherence was 93.1%. High-dose intracoronary adenosine was injected in 78.5% of the vessels. The dose escalation strategy was well-tolerated without serious complications. The positive rate increased significantly after conducting the protocol compared to that with a conventional dose (28.2% vs. 23.6% with an FFR threshold of 0.75, and 48.7% vs. 42.5% with a threshold of 0.80, both p < 0.05). In the validation cohort, only FFR ≤ 0.75 was associated with the binary result of the non-invasive pretest (p < 0.01 vs. p = 0.37). The high-dose adenosine escalation strategy did not increase the accuracy of FFR (77.8% vs. 75.6% in conventional dose and high-dose adenosine, respectively). Conclusions: The use of a high-dose escalation strategy increased the positive rate in FFR assessments.