HYPERTENSION

Raised blood pressure (BP). BP is the pressure of the blood on the walls of the arteries, and depends on the energy of the heart’s action, the elasticity of the artery walls and the volume and viscosity of the blood. BP is measured with a sphygmomanometer (sphygmo-, relating to the pulse; manometer, device for measuring pressure) and the result expressed in millimetres of mercury (mmHg) as, e.g. 140/75 mmHg, where 140 mmHg is the systolic pressure (maximum pressure, as the ventricles contract) and 75 mmHg is the diastolic pressure (minimum pressure, as the heart rests). Hypertension (raised blood pressure) is a major risk factor for coronary heart disease and stroke. It is a clinical sign that causes few symptoms until there is end-organ damage. In most people with hypertension, it has no single, identifiable cause; in others it is secondary to another disorder.

See also Diabetes, CHD, CKD

Measuring blood pressure

• Use a validated monitor – see list at https://bihsoc.org
• Have patient rest for 3 min before taking reading
• Use an appropriately sized cuff
• Rest arm at level of heart
• Initially check reading in both arms. Subsequently use arm with highest reading
• In elderly people and those with diabetes, check BP readings standing and sitting
• Record reading immediately
• Repeat reading after 2 min

Confirming the diagnosis

If clinic blood pressure is 140/90mmHg or higher, offer ambulatory BP monitoring (ABPM) to confirm diagnosis. Home BP monitoring (HBPM) is a suitable alternative for people unable to tolerate ABPM. Carry out investigations for target organ damage (heart, eyes, kidneys) and formally assess cardiovascular risk.

For all people with hypertension, offer to:

• Test for the presence of protein in the urine by sending a urine sample for the estimation of the albumin: creatinine ratio, and test for haematuria using a reagent strip
• Take a blood sample to measure HbA1c, electrolytes, creatinine, eGFR, total cholesterol and HDL cholesterol
• Examine the fundi for the presence of hypertensive retinopathy
• Perform, or arrange for, a 12-lead ECG.

For a visual summary of treatment recommendations from NICE, see Choice of antihypertensive drug, monitoring treatment and BP targets, https://www.nice.org.uk/guidance/ng136/resources/visual-summary-pdf-6899919517