Load-dependent mechanisms contribute to increased aortic stiffness among women with a history of preeclampsia: relation with cardiovagal baroreflex sensitivity

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 <i>1</i>) whether elevated total aortic stiffness among women with a history of preeclampsia (hxPE) is attributed to load-dependent or structural stiffness, and <i>2</i>) whether either mechanism is associated with lower BRS. Total aortic stiffness (carotid-femoral pulse wave velocity) and spontaneous cardiovagal BRS (sequence technique) were measured among women 1-5 yr postpartum (<i>n</i> = 115; age 34 ± 4 yr; hxPE <i>n</i> = 51; controls <i>n</i> = 64). Structural aortic stiffness was calculated from participant-specific exponential models by standardizing aortic stiffness to a "reference" blood pressure. Load-dependent stiffness was calculated as total minus structural stiffness. Total [+0.8 m/s, 95% confidence interval (CI) (-0.99, -0.23), <i>P</i> = 0.002] and load-dependent [+0.4 m/s, 95% CI (-0.56, -0.22), <i>P</i> < 0.001], but not structural [95% CI (-0.52, 0.08), <i>P</i> = 0.16] aortic stiffness were higher among women with a hxPE compared with controls. Women with a hxPE had lower BRS (<i>P</i> = 0.042) that was negatively associated with total [<i>B</i> = -3.24 ms/mmHg, 95% CI (-6.35, -0.13), <i>P</i> = 0.042] and load-dependent [<i>B</i> = -5.91 ms/mmHg, 95% CI (-11.31, -0.51), <i>P</i> = 0.033] aortic stiffness. Load-dependent, not structural, aortic stiffness mechanisms contribute to higher total aortic stiffness among women with a hxPE and are associated with lower cardiovagal BRS. Postpartum monitoring for high BP is critical to reduce increased CVD risk after preeclampsia.<b>NEW & NOTEWORTHY</b> The novel finding is that load-dependent stiffness, not structural stiffness, is the primary mechanism of aortic stiffness, and is associated with reduced baroreflex sensitivity in women with a history of preeclampsia. These findings may help tailor high blood pressure prevention and management strategies in this population to prevent structural aortic stiffening, altered baroreflex control, and increased lifetime cardiovascular disease (CVD) risk.