Load-Dependent Mechanisms Contribute to Increased Aortic Stiffness Among Women with a History of Preeclampsia: Relation with Cardiovagal Baroreflex Sensitivity.

Introduction: Preeclampsia, a hypertensive disorder of pregnancy, results in increased lifetime cardiovascular disease (CVD) risk. Total aortic stiffness, a robust risk factor for CVD, is composed of load-dependent (blood pressure load on arterial wall) and structural (intrinsic changes in arterial wall) mechanisms. Total aortic stiffness is also associated with reduced cardiovagal baroreflex sensitivity (BRS). We sought to determine 1) whether elevated total aortic stiffness among women with a history of preeclampsia (hxPE) is attributed to load-dependent or structural stiffness, and 2) whether either mechanism is associated with lower BRS. Methods: Total aortic stiffness (carotid-femoral pulse wave velocity) and spontaneous cardiovagal BRS (sequence technique) were measured among women 1-5 years postpartum (n=115; age 34 ±4yrs; hxPE n=51; controls n=64). Structural aortic stiffness was calculated from participant-specific exponential models, standardizing aortic stiffness to a 'reference' blood pressure. Load-dependent stiffness was calculated as total minus structural stiffness. Results: Total (+0.8 m/sec, 95% CI (-0.99, -0.23), p=0.002) and load-dependent (+0.4 m/sec, 95% CI (-0.56, -0.22), P<0.001), but not structural (95% CI (-0.52, 0.08), p=0.16), aortic stiffness were higher among women with hxPE compared with controls. Women with a hxPE had lower BRS (p=0.042) that was negatively associated with total (B =-3.24 ms/mmHg, 95% CI (-6.35, -0.13), p=0.042) and load-dependent (B =-5.91ms/mmHg, 95% CI (-11.31, -0.51), p=0.033) aortic stiffness. Conclusion: Load-dependent, not structural, aortic stiffness mechanisms contribute to higher total aortic stiffness among women with hxPE and was associated with lower cardiovagal BRS. Postpartum BP monitoring is critical to reduce increased CVD risk in preeclampsia.