The Relationship between Resistant Hypertension and Arterial Stiffness

Objectives: With growing awareness of arterial stiffness (AS) in the past 10 years, it was realized that resistant hypertension (RH) and AS share the same associated conditions such as older age, isolated systolic hypertension (HT), obesity, chronic kidney disease (CKD), and so on. Until now, there is no study investigating the role of AS in RH. In our study we aimed to determine whether there is an association between RH and AS. Methods: Among 87 patients enrolled in this study, 30 were resistant hypertensives (Group 1), 29 were controlled hypertensives (Group 2), and 28 were normotensives (Group 3). Arterial stiffness was measured by both applanation tonometry and echocardiography; augmentation index, pulse wave velocity (PWV), aortic strain, and aortic distensibility were recorded in each patient. Diastolic function parameters were also assessed. Results: In resistant hypertensive group, augmentation index and PWV were significantly higher than Group 2 and Group 3 (P = .03 and P < .01). Aortic strain and aortic distensibility parameters were significantly lower in RH group (P < .01 and P < .01). Arterial stiffness parameters were similar among Group 2 and Group 3. Among diastolic function parameters, left atrial volume index and left ventricular mass index significantly differ between groups. These two parameters were significantly lower in control group (P < .01 and P = .02) whereas similar in Group 1 and Group 2. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels were significantly different between groups as expected. When the correlation between two methods of AS was analyzed, a significant strong inverse correlation was found between echocardiographic and tonometric parameters. Conclusion: Arterial stiffness was found to be associated with RH. The inconsistency of this association in controlled hypertensives suggests a possible role of AS in RH pathogenesis. This study also showed that aortic strain and distensibility correlate well with the PWV which is the gold standard in the assessment of AS. This finding is important for the evaluation of AS more commonly in daily practice as echocardiography is a more feasible device than applanation tonometry.