P5621Diagnostic accuracy of resting full-cycle ratio in the non-culprit artery of acute patients

Abstract

Abstract Introduction Resting full-cycle ratio (RFR) is a novel non-hyperemic index of coronary stenosis severity, independent of the timing within the cardiac cycle. Recent data has demonstrated good correlation between RFR and Fractional Flow Reserve (FFR) in stable coronary disease (SCD). However, there are no data regarding the reliability of RFR in non-culprit arteries of patients presenting with acute myocardial infarction (AMI). Purpose To study the diagnostic accuracy of RFR versus FFR in the non-culprit artery in AMI compared to stable lesions. Methods RFR, FFR, Coronary Flow Reserve (CFR), Index of Microcirculatory Resistance (IMR), and Resistance Reserve Ratio (RRR) were calculated in 67 patients with AMI and an intermediate lesion in a non-culprit artery (median time from primary PCI to study: 48 hours). Data were compared with those of a retrospective group of 66 patients with SCD. Results There was a higher proportion of males among patients of the AMI group (85% vs 62%, p=0.0026). Mean age was 64.5±11 years, being AMI cohort younger at presentation [62±11 vs 67±12 years in SCD cohort (p=0.04)]. Patients with AMI had a significantly lower prevalence of hypertension (52% vs 75%, p=0.006), diabetes (10% vs 32%), p=0.002) and hyperlipemia (37% vs 79%, p=0.002). Coronary physiology parameters showed a non-normal distribution, and are expressed as median [IQR] (Table 1). In patients with AMI, FFR was lower than in patients with SCD. In contrast, RFR showed no significant difference. Both CFR and RRR were higher in the AMI group. No significant differences in IMR were found between cohorts. Importantly, in the AMI group the correlation between RFR and FFR was 0.84 and the overall agreement 82%, with rates of false positive and negative of 15% and 3%, respectively. In SCD the correlation was 0.81 with a lower overall agreement of 69%, due mostly to a higher rate of false positive RFR (28%) (Figure 1). Table 1. Microcirculatory parameters in non-culprit artery (AMI) and stable coronary disease (SCD) AMI (N=66) Stable (N=67) p value FFR 0.84 [0.76–0.9] 0.84 [0.76–0.9] 0.006 RFR 0.89 [0.82–0.94] 0,9 [0.84–0.94] 0.24 CFR 2.2 [1.7–3.1] 1.8 [1.1–2.6] 0.011 IMR 17 [14–27] 25 [14–38] 0.051 RRR 2.7 [2.17 - 3.9] 2.1 [1.4–3.1] 0.005 Median [IQR]. Figure 1. Correlation between RFR and FFR valueS Conclusions RFR shows a good correlation with FFR in AMI. Surprisingly, overall agreement is higher in the non-culprit artery in an acute setting, with a lower percentage of false positive results. Acknowledgement/Funding None