Author + information
- Alejandro Velasco,
- Mohammed Siddiqui,
- Steven Lloyd,
- Suzanne Oparil and
- David Calhoun
Background: Refractory hypertension (RFH) is defined as the lack of blood pressure (BP) control with 5 or more medications, including chlorthalidone and a mineralocorticoid receptor blocker. RFH patients are at high cardiovascular risk. Previous studies from our laboratory suggest that RFH is characterized by increased sympathetic activity as opposed to persistent intravascular fluid retention, as is the case for resistant hypertension (RHTN) in general. Our aim was to perform a detailed cardiac phenotyping of RFH and compare it to patients with controlled RHTN, evaluating cardiac chamber volumes as an index of intravascular volume status.
Methods: Consecutive patients evaluated in the UAB Hypertension Clinic with RFH and controlled RHTN were prospectively enrolled. A clinic cutoff of 140/90 mmHg was used to define controlled BP. Cases of advanced chronic kidney disease, along with masked and white coat hypertension were excluded based on 24-hr ambulatory BP monitoring. Enrolled patients underwent extensive biochemical testing as well as evaluation by cardiac MRI.
Results: Patients with RFH (n=25) were younger (mean age 51±9 vs. 58±12 years, p=0.038) and had a greater proportion of female patients (77% vs. 44%, p=0.021) compared to the controlled RHTN group (n=22). No significant differences were found in BMI, diabetes or sleep apnea among groups. RFH patients, in comparison to controlled RHTN, had a higher left ventricular mass indexed by BSA (91±40 vs. 57±13 gr/m2 p<0.001), greater posterior wall thickness (10.4±3.5 vs. 7.7±1.7 mm, p< 0.001) and interventricular septum thickness (15±4.3 vs. 11.1±2.4 mm, p<0.001). Notably, there was no difference in left atrial volume indexed by BSA (32±9 vs. 33±14 ml/m2, p=0.768) and end diastolic LV volumes (135±35 vs. 142±38 ml, p=0.658). RFH patients had a smaller right atrial volume (40±8 vs. 50±6 ml, p=0.004).
Conclusions: Our findings demonstrate substantially greater LVH in patients with RFH compared to patients with controlled RHTN. The lack of atrial or ventricular volume enlargement suggest that RFH is not attributable to persistent intravascular fluid retention and lends support to an alternative cause of RFH, such as excess sympathetic output.
Poster Hall, Hall C
Friday, March 17, 2017, 3:45 p.m.-4:30 p.m.
Session Title: Novel Mechanical Devices for the Treatment and Assessment of Hypertension
Abstract Category: 33. Prevention: Hypertension
Presentation Number: 1146-037
- 2017 American College of Cardiology Foundation