Hypertension Circulatory System Hypertensive diseases
Conditions
Interventions
Participants with high blood pressure will be recruited from the Hypertension Clinic at the Bristol Heart Institute. We will also apply for the study to be included in the NIHR Clincial Research Netwo
study adverts placed in community/University newsletters
study adverts emailed through University Faculty email
and information on the CRIC Bristol Website. Permission will be gained before posters/leaflets are left in public spaces and before adverts are emailed through University email. The study will also be
Sponsors
University of Bristol
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: 1. Aged 18-75 years 2. Hypertensive patients: Office blood pressure = 140/90 mmHg and daytime ambulatory blood pressure =135/85 mmHg 3. Normotensive participants: Office blood pressure < 140/90 mmHg and daytime ambulatory blood pressure < 135/85 mmHg 4. Postmenopausal women: No period for at least 12 months and not using hormonal contraception (NICE, 2015)
Exclusion criteria
Exclusion criteria: 1. Secondary causes of hypertension 2. Body mass index > = 30 kg/m2 3. Oophorectomy (removal of ovaries) prior to onset of natural menopause 4. Pregnancy/breastfeeding women 5. Taking hormone replacement therapy 6. Taking nitrate, steroid, anti-coagulant or immunosuppressant medication or medication as part of a clinical trial 7. Major illness e.g. cancer, inflammatory disease (including vasculitis) or receiving palliative care 8. Diagnosed cardiovascular (including arrhythmia), respiratory (including asthma), psychiatric, renal or ophthalmic disease 9. Congenital or acquired neurological conditions (including dementia), language disorders, repeated or chronic pain conditions (excluding menstrual pain and minor sporadic headaches) 10. Diabetes 11. Symptoms of febrile illness less than a week before experiment 12. Excessive alcohol consumption (> 28 units/week) or use of illicit drugs 13. Needle phobia 14. Inability to understand instructions given in English 15. Mild, moderate or severe persistent asthma (due to potential broncho effects of a systemic beta-blocker) For premenopausal women and younger men only (relating to the propranolol infusion): 1. Individuals with any of the conditions listed in the instructions for use document of Dociton solution of injection (propranolol hydrochloride) in which Dociton must not be used: 1.1. Hypersensitivity to propranolol/beta-blockers or other ingredients in Dociton 1.2. Heart muscle weakness 1.3. Shock 1.4. Grade II or III AV block 1.5. Sick sinus syndrome 1.6. Sino-atrial block 1.7. Bradycardia (resting pulse < 50 beats/min) 1.8. Hypotension 1.9. Acidosis 1.10. Taking MAO inhibitors 1.11. Late stage peripheral blood flow disorders 1.12. tendency towards bronchial spasm e.g. bronchial asthma. 2. Individuals with any condition listed in the instructions for use document in which Dociton should be used with caution: 2.1. Grade I AV block 2.2. Diabetes mellitus 2.3. Lengthy strict fasting and severe physical stress 2.4. Phaeochomocytoma 2.5. Impaired liver or kidney function 2.6. Individual/family history of psoriasis 2.7. History of severe hypersensitivity reaction or receiving treatment to weaken allergic reactivity). 3. Individuals taking/recently taken any medication listed in the instructions for use document as being affected by Dociton or affecting Dociton: 3.1. Insulin/oral antidiabetics 3.2. Other blood pressure-lowering medications, nitroglycerin, diuretics, vasodilators, tricyclic antidepressants, phenothiazines, barbituates 3.3. Calcium antagonists of the nifedipine type 3.4. Calcium antagonists of the verapamil or diltiazem type 3.5. Antiarrhythmics, e.g. disopyramine or others 3.6. Cardiac glycosides 3.7. Reserpine 3.8. Alpha-methyldopa 3.9. G
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. Level of sympathetic nerve activity measured using microneurography at baseline 2. Level of sympathetic vascular transduction measured using microneurography & vascular ultrasound at baseline | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. The change in sympathetic vascular transduction measured using microneurography & vascular ultrasound at baseline and during block of beta-adrenergic receptors (during propranolol infusion) 2. The vasodilator response (increase in blood flow) to handgrip exercise measured using vascular ultrasound at baseline | — |
Countries
United Kingdom
Outcome results
None listed