Fractional flow reserve in anomalous aortic origin of coronary arteries to evaluate hemodynamic consequences of high risk anatomical features

Abstract Introduction In patients with anomalous aortic origin of a coronary artery (AAOCA) fractional flow reserve (FFR) can be performed for further risk stratification of myocardial ischemia and sudden cardiac death. The aim of this study was to evaluate the hemodynamic consequences (accessed with FFR) of the high-risk anatomical features in AAOCA. Methods In this prospective cohort study, all consecutive patients with AAOCA in whom diagnostic work-up according to the MuSCAT trial, including FFR, was performed between July 2020 and January 2023 in our tertiary AAOCA referral center, were included. Presence and length of the intramural segment was assessed using the interluminal space (ILS) on the CTA and orifice geometry using IVUS. Results Thirty patients, 57% female and mean age at AAOCA diagnosis of 48.7±15.3 years, were included. Twenty-seven (90%) patients presented with an anomalous aortic origin of the right coronary artery. FFR adenosine was measured in all patients (Figure 1), and showed a significant relation with: 1. hypoplasia of the proximal segment on CTA (R=0.400, p=0.029); 2. the ILS at 2mm from the ostium on CTA (R=0.517, p=0.003); 3. the length of the intramural course on CTA (R=0.500, p=0.005); 4. the orifice shape on IVUS (R=0.460, p=0.011) and 5. the minimal lumen area on IVUS (R=0.371, p=0.044). Conclusions FFR was significantly reduced in AAOCA with the following high-risk anatomical features: increased hypoplasia of the proximal segment on CTA, lower ILS at 2mm from the ostium on CTA, longer intramural course on CTA, increased slitlike orifice shape on IVUS and lower minimal lumen area on IVUS. These anatomical high-risk features appear to be hemodynamically relevant in the pathophysiology of AAOCA.Figure 1