Sex Differences in Cardiac Flow Dynamics of Healthy Volunteers

Abstract

Purpose To further understand the relationship between cardiac function and flow, on the basis of sex, by quantifying cardiac flow characteristics and relating them to cardiac muscle performance in young adults. Materials and Methods In this cross-sectional study, cardiac four-dimensional flow MRI and two-dimensional cine MRI were performed in 20 male and 19 female volunteers aged 20–35 years. Velocity-based metrics of flow, kinetic energy (KE), vorticity, and efficiency indexes were quantified, as well as cardiac strain metrics. Results Peak systolic blood KE (men: 4.76 mJ ± 2.66 [standard deviation]; women: 3.36 mJ ± 1.43; P = .047) was significantly higher in the male left ventricle (LV) than in the female LV. Peak systolic vorticity index (men: 0.008 radian · m2/mL · sec ± 0.005; women: 0.014 radian · m2/mL · sec ± 0.007; P = .007), peak diastolic vorticity index (men: 0.007 radian · m2/mL · sec ± 0.006; women: 0.014 radian · m2/mL · sec ± 0.010; P = .015), and cycle-average vorticity (men: 0.006 radian/sec ± 0.001; women: 0.011 radian/sec ± 0.002; P = .001) were significantly higher in the LV of women than they were in the LV of men. Radial, circumferential, and long-axis strain metrics were significantly higher in the female LV than in the male LV (P < .05). Circumferential systolic and diastolic strain rates displayed moderate correlation to peak systolic (r = −0.38; P = .022) and diastolic vorticity (r = 0.40; P = .015) values, respectively. Results are reported as mean ± standard deviation. Conclusion LV vorticity metrics were observed to be higher in women than in men and displayed moderate correlation to cardiac strain metrics. The methods and results of this study may be used to further understand the sex-based cardiac efficiency relationship between cardiac function and flow. Keywords: Adults, Cardiac, Heart, MR-Imaging, Physiological Studies © RSNA, 2020 See also the commentary by Ordovas in this issue.

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