Abstract
Background
Since the ascending aorta is just distal to the left ventricle, ascending aorta stiffness and ventriculoarterial coupling both have significant implications on cardiac strain and pressure transmission to downstream end-organs. We novelize a method using cardiac MRI (CMR) to quantify aortic global longitudinal strain (AoGLS), pulse wave velocity (AAPWV), and ventriculoarterial coupling (VAC) to characterize strain patterns in ageing adults.
Methods
Community adults without CVD at baseline underwent CMR. AoGLS was the maximal absolute Lagrangian strain tracking the phasic distance between brachiocephalic artery origin and aortic annulus (Figure 1). VAC was calculated as AAPWV divided by LVGLS. Sex-specific Framingham-based (FRS) 10-year risk (TYR) were computed.
Results
Of 202 participants (46.0% women), mean ages between women and men were similar (69.70 years vs 70.69 years, p=0.433). Compared with men, women had better aortic compliance as indicated by lower mean pulse wave velocity (8.408m/s vs 9.131m/s, adjusted-p=0.020) and higher aortic global longitudinal strain (6.164% vs 5.210% adjusted-p=0.030) which remained significant after adjusting for diastolic blood pressure, body surface area, and smoking status (β=0.838 95%CI 0.080, 1.596 adjusted p=0.030). Ventriculoarterial coupling was better (less negative) in women than men (-0.392 m/s·% vs -0.471 m/s·%, adjusted p=0.006) but the strength of association between VAC and sex was negligible. Among women, the correlations between AoGLS and 10-Year Risk (r=-0.400 95%CI -0.558,-0.213 p=0.0001) and Heart/Vascular Age (r=-0.621 95%CI -0.732,-0.478 p<0.0001) were low and moderate negative, respectively; whereas among men, these correlations were both low negative (10-Year Risk r=-0.365 95%CI -0.518,-0.190 p=0.0001; Heart/Vascular Age r=-0.354 95%CI -0.508,-0.178 p=0.0002).
Conclusion
We characterized a central marker of aortic ageing and its anatomical relationship to ventriculoarterial coupling that is novel and non-invasive. Aorto-ventricular strain and coupling in Asian older adults correlated with 10-year CVD risk. Future work will assess the incremental value of using advanced aortic function to define CV aging in Asian cohorts.