RESISTANT HYPERTENSION – PATHOLOGICAL INSIGHTS FROM CARDIAC MECHANICS

Abstract

Introduction: Patients with resistant hypertension suffer from a high rate of cardiovascular complications and have poor prognosis. Given the poor prognosis in patients with resistant hypertension, early identification of abnormalities in cardiac mechanics, arterial stiffness, endothelial function and autonomic function is of clinical importance to aid in risk stratification and enable timely therapeutic interventions. There are limited data on left ventricular (LV) and left atrial (LA) mechanics, arterial stiffness, endothelial function, and autonomic function assessed by heart rate variability (HRV) in patients with resistant hypertension. Additionally, the relationship between measures of cardiac mechanics, arterial stiffness, endothelial function and autonomic function, as well as the effects of intensified blood pressure (BP) management on these indices, have not yet been investigated in resistant hypertension population.

Aims: This study aimed to investigate LV and LA mechanics, arterial stiffness, endothelial function and autonomic function in patients with resistant hypertension, controlled essential hypertension and normotensive controls, and to determine the association between these measures in patients with resistant hypertension. Furthermore, to evaluate the effects of 8 weeks of intensified BP management on LV and LA mechanics, arterial stiffness, endothelial function and autonomic function in patients with resistant hypertension.

Methods: A prospective cross-sectional study included 54 participants (17 with resistant hypertension, 18 with controlled hypertension, and 19 normotensive controls), while the longitudinal study included 16 patients with resistant hypertension. Participants underwent transthoracic echocardiography, speckle tracking echocardiography to assess LV and LA mechanics, pulse wave analysis to evaluate arterial stiffness determined by aortic augmentation index (AIx), flow-mediated dilatation (FMD) to assess endothelial function, and HRV to evaluate autonomic function. Results: Patients with resistant hypertension had higher office and central BP, pronounced cardiac remodelling, impaired LV and LA mechanics, increased AIx and lower FMD compared to controlled hypertension and normotensive controls. Several HRV variables were significantly reduced in resistant hypertension compared to normotensive controls. Lower FMD was associated with worse LV longitudinal deformation and reduced HRV indices were related to increased LV twist among patients with resistant hypertension. Following 8 weeks of optimising antihypertensive treatment, patients with resistant hypertension exhibited significant reductions in office and central BP, AIx, as well as significant improvements in LV and LA mechanics, FMD, and total power (TP) index of HRV compared to baseline.

Conclusion: Patients with resistant hypertension show evidence of greater cardiac remodelling with concomitant impairment of their LV and LA mechanics, increased arterial stiffness and worsened endothelial function compared to controlled hypertension and normotensive controls. Patients with resistant hypertension exhibited impairment in several HRV indices compared to normotensive controls. Intensive BP management for 8 weeks in patients with resistant hypertension has a favourable impact on LV and LA mechanics, arterial stiffness, endothelial function, and the TP spectrum of HRV. The assessment of cardiac mechanics, arterial stiffness, endothelial and autonomic function in patients with resistant hypertension may have valuable prognostic and therapeutic implications.