Sex differences in the visual-functional mismatch between coronary angiography or intravascular ultrasound versus fractional flow reserve.

OBJECTIVES: This study sought to assess differences in visual-functional mismatches between men and women.

BACKGROUND: Sex differences in mismatch between coronary anatomy and function remain poorly understood.

METHODS: We assessed quantitative coronary angiography, intravascular ultrasound (IVUS), fractional flow reserve (FFR), and echocardiographic left ventricular mass in a prospective cohort of 700 patients (493 male and 207 female patients) with 700 left anterior descending coronary lesions.

RESULTS: The female patients were older than the male patients (64 ± 10 years vs. 60 ± 10 years, p < 0.001) and body surface area (BSA) (57 ± 0.13 m(2) vs. 1.79 ± 0.13 m(2), p < 0.001) and left ventricular mass (151 ± 37g vs. 171 ± 41 g, p < 0.001) were smaller. Although there were no sex differences in angiographic diameter stenosis, lesion length, and IVUS minimal lumen area (MLA), FFR was higher in female patients (0.83 ± 0.09 vs. 0.79 ± 0.09, p < 0.001). Female patients had a smaller reference vessel area (11.4 ± 3.3 mm(2) vs. 13.1 ± 4.0 mm(2)), vessel area (9.0 ± 3.3 mm(2) vs. 11.1 ± 4.2 mm(2)), and plaque burden (69.8 ± 13.7% vs. 73.8 ± 12.2%) at the MLA site compared with male patients (all p < 0.001). To predict FFR <0.80, angiography had a lower positive predictive value in female patients (44% vs. 60%, p = 0.014); this was also seen in the IVUS analysis. Unlike angiography, the IVUS-MLA had a lower concordance rate in female patients (64% vs. 71%, p = 0.046). Independent predictors of FFR were age, BSA, lesion length, angiographic diameter stenosis, and IVUS-MLA and plaque burden. When left ventricular mass was included, it also predicted FFR, replacing BSA.

CONCLUSIONS: In female patients with smaller BSA, left ventricular mass, and vessel size, smaller myocardial territory may be responsible for the higher FFR value for any given stenosis compared with male patients. Considering the higher rate of visual-functional mismatch, FFR-guided decision making is especially important in female patients to avoid unnecessary procedures. (Natural History of FFR-Guided Deferred Coronary Lesions [IRIS FFR-DEFER Registry]; NCT01366404).