Arterial stiffness assessment in patients with resistant hypertension using pulse wave analysis

Abstract

Abstract Introduction People living with resistant hypertension (RH) have a higher prevalence of target organ damage, and demonstrate increased risk of cardiovascular (CV) morbidity and mortality. There are distinctive vascular structural and functional changes associated with hypertension. Among these, endothelial dysfunction and increased arterial stiffness are prevalent. Increased aortic augmentation index (AIx) is a non-invasive hemodynamic indicator of systemic arterial stiffness, which has been associated with hypertension; however, there are less data in RH patients. Purpose To test the hypothesis that people living with RH have increased AIx compared to those with controlled essential hypertension (CH) and normotensive controls (NC); and to explore demographic and clinical variables related to AIx. Methods In our observational study, 54 participants: 17 with RH (mean age 60.5±12.4 years), 18 with CH (57.7±12.2 years), and 19 NC (54.7±11.9 years) were recruited. Anthropometric and resting office blood pressure (BP) measurements were obtained. Pulse wave analysis was performed using a commercially available device (Vicorder) to measure central BP, aortic pulse pressure, mean arterial pressure (MAP), aortic augmentation pressure and AIx. Results The study groups were matched for age, sex, ethnicity, height, body surface area and heart rate (P>0.05) (Table 1). Both office and central BP readings were elevated in RH group compared to CH and NC (162/102mmHg vs 126/86mmHg and 118/80mmHg, P<0.001) and (163/83mmHg vs 131/73mmHg and 120/67mmHg, P<0.05). Aortic pulse pressure, MAP and aortic augmentation pressure were significantly increased in patients with RH compared to other groups (P<0.001). AIx was markedly increased in RH compared to CH and NC (31±7% vs 23±8% and 21±9%, P=0.001, respectively). Antihypertensive medications were similar between both hypertensive groups, except for diuretics and beta-blockers which were more prevalent in the RH group (100% vs 28% and 47% vs 6%, P<0.05, respectively). In stepwise regression analysis, elevated AIx was significantly and independently associated with the presence of RH (β=6.4, P=0.005), age (β=.23, P=0.005), female sex (β=6.3, P=0.003) and body mass index (β=.71, P=0.038). Conclusion AIx is increased in RH patients and independently related to the presence of RH, age, female sex and body mass index. Increased arterial stiffness and reduced arterial compliance in patients with RH may play an important role in the progression of serious CV complications seen in these patients. The non-invasive assessment of arterial stiffness indices such as AIx in RH patients may be valuable to provide prognostic and therapeutic insights.Table 1