The hemodynamic effects of a central iliac arteriovenous anastomosis at 6 months in patients with resistant and uncontrolled hypertension

Abstract

A central iliac arteriovenous anastomosis, termed the "coupler" (ROX Medical), results in a significant reduction in blood pressure (BP) in hypertensive patients. This study assessed functional and hemodynamic changes induced by the device. Twenty-one patients with resistant and/or uncontrolled hypertension underwent stress echocardiography and cardiopulmonary exercise testing (CPET) at baseline and 6 months post-coupler implantation. End points were selected to best evaluate cardiac function including Doppler stroke volume (SV), septal and lateral E/E′, and right ventricular systolic velocity S′ (RV S′). CPET VO 2 peak demonstrated total cardiopulmonary performance. SV increased from 76.4 SD12.2 mL to 92.1 SD22.7 mL 6 months postcoupler insertion; P = .002. No changes in RV S′, septal or lateral E/E′, or VO 2 peak were observed. Five patients experienced increased diuretic requirement ≥3 times baseline. RV S′ fell from 19.0 SD1.87 cm/s to 16.80 SD3.43 cm/s in these patients (P > .05). A significant increase in SV 6 months post-coupler insertion was observed.In patients with increased diuretic requirement, the device was associated with a lower RV S′ suggesting occult RV dysfunction as the mechanism of this pre-specified adverse outcome. |EYSENCK Et al. changes and detailed assessment of these with CPET stress echo predicts patients at risk of increased diuretic requirement post-coupler insertion. | ME THODS | Study design and participantsThis study was performed at Eastbourne General Hospital, East Sussex Healthcare NHS Trust, UK, and was approved by the UK national ethics committee. Twenty-one consecutive participants with resistant and/or uncontrolled hypertension taking part in the ROX Control Hypertension Registry (RH-03) NCT01885390 were included. 10 The rationale and design of the RH-03 registry have been described previously. 10 Inclusion criteria were patients aged 18-85 years with a diagnosis of resistant or uncontrolled hypertension made on the basis of office and 24-hour BP monitoring, medical history, and physical examination. Resistant hypertension was defined as patients with established hypertension (diagnosed ≥12 months prior to baseline) on a guideline-based drug regimen at a stable and a fully tolerated dose, consisting of ≥3 hypertensive medications (including 1 diuretic). Uncontrolled hypertension was defined as patients with hypertension and drug intolerances to antihypertensive medications and unable to take a guideline-based drug regimen. Patients were excluded if they had any serious medical condition that might have adversely affected the patient's safety, limit the subject's ability to participate in the registry, comply with follow-up requirements, or impact the scientific integrity of the study. In addition, patients were excluded if found to have a baseline pulmonary capillary mean wedge pressure >15 mm Hg at right heart catheterization. Written informed consent was obtained from all participants. All 21 participants underwent baseline and 6 months post-coupler stress echo CPET ex...