Abstract Body (Do not enter title and authors here): Background: Angina with no obstructive coronary arteries (ANOCA) is clinically challenging to diagnose and manage. The agreement between Doppler-derived coronary flow reserve (CFR_Doppl) and PET-derived CFR (CFR_PET) in patients with ANOCA remains unclear.
Aims: To evaluate the correlation between Doppler- and PET-derived CFR in patients with ANOCA.
Methods: We conducted a single-center, retrospective study of adult patients (age ≥18 years) with ANOCA who were referred for evaluation of possible microvascular ischemia with Doppler- and PET-derived CFR at the Mayo Clinic (Rochester, MN) between January 1, 2018, and May 1, 2024. Pearson correlation was used to quantify the association between Doppler- and PET-derived CFR. Agreement between Doppler- and PET-derived CFR was assessed by Bland-Altman analysis using a 2-way mixed effects model with measures of absolute agreement.
Results: A total of 66 patients were initially identified, of which 40 were included in the final analysis (66.7% female, median age 58 years [Q1-Q3: 45-66 years]). Median time between PET- and Doppler-derived CFR was 8 days (Q1-Q3: 1-31 days). Median CFR_Doppl was 2.75 (IQR: 2.23-3.28) and median CFR_PET was 2.50 (IQR: 2.10-3.10). Doppler-derived CFR displayed a wider range than PET-derived CFR (0.8-5.2 vs 1.2-4.0). A strong correlation was found between Doppler- and PET-derived CFR (r=0.81; p<0.001). The corresponding Bland-Altman plot showed an overall bias of 0.27±0.56 (intraclass coefficient=0.85; p<0.001).
Conclusions: While invasive coronary angiography with CFR_Doppl is the gold-standard for the diagnostic evaluation of ANOCA, PET imaging with CFR_PET offers an excellent first line non-invasive modality for diagnosis of coronary microvascular dysfunction.