This is a pilot study to assess the effectiveness, safety and feasibility of carotid body removal in patients with high blood pressure (hypertension) resistant to medical treatment. Patients with high blood pressure are at significant risk of medical complications including stroke and heart disease. The principle research question is whether removal of the carotid body will lead to an improvement in the blood pressure of this patient group.

Inclusion Criteria:

• Age of participants will be 18-75 years

• Resistant HTN criteria:

  1. Daytime mean ambulatory systolic blood pressure ≥135mmHg and office systolic blood pressure ≥150mmHg
  2. Patients on at least three anti-hypertensive medications, including a diuretic, at maximum tolerated dose
  3. No evidence of causes for secondary HTN following thorough clinical assessment
  4. Patient medication concordance will be monitored via medication/blood pressure diary

Exclusion Criteria:

• Calculated GFR <45ml/min/1.73m2
• Carotid body located outside the defined carotid septum
• Obstructive carotid atherosclerotic disease with >50% stenosis
• Oxygen desaturation at rest below 92%
• Known structural lung disease
• Requirement for oxygen therapy to maintain oxygen saturation
• Patients wish to participate in mountain climbing, skin diving or free diving
• Pregnancy or anticipation of pregnancy
• Palliative care/chemotherapy
• Acute coronary syndrome or unstable angina
• Stroke or transient ischaemic attack (TIA) < 6 months prior to procedure
• Expected life expectancy less than 12 months due to other disease
• Intravenous drug use
• Alcohol intake >28 units/week
• Febrile illness within two weeks of participation
• Unable to attend for follow up appointments in Bristol at 1, 3, 6, 12 and 24 months post-operatively.

MR imaging related exclusion criteria (all participants):

• Pace-maker, implantable cardiac defibrillator, cerebral metallic clips or other implanted metal devices/structures
• Unable to tolerate scanner or history of panic attacks/claustrophobia
• Learning disability, significant hearing or visual impairment (participant would need to able to communicate from within the MRI scanner)