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Patients with resistant hypertension are at high risk for adverse cardiovascular
events and are more likely than those with controlled hypertension to have a second-
ary cause, which is usually at least in part reversible.
Typical Characteristics of Patients with Resistant
Hypertension
- Older age; especially >75 years
- High baseline blood pressure and chronicity of uncontrolled hypertension
- Target organ damage (e.g. left ventricular hypertrophy, chronic kidney disease)
- Diabetes
- Obesity
- Atherosclerotic vascular disease
- Aortic stiffening—systolic > > diastolic BP elevation
- Female gender
- Black race
- Excessive dietary sodium intake
Biochemical Evaluation for Patients with Suspected Resistant
Hypertension
Preliminary biochemical tests should be conducted before specialist referral. These
can help to delineate a potential secondary cause of resistant hypertension whether
unearthed by the patient’s history and physical examination or not, signal the devel-
opment of renal dysfunction and help monitor the response to and side effects from
antihypertensive agents.
- Urea and electrolytes
- Estimated glomerular filtration rate
- Plasma glucose
- Plasma renin/aldosterone levels
- 24-hour urinary metanephrines or normetanephrines (for phaeochromocytoma)
- Urine analysis—microalbuminuria and macroalbuminuria, invisible haematuria
D. Goldsmith and S. Badarau