Resistant hypertension is defined as the failure to reach blood pressure control in patients who are adherent to full doses of an appropriate three-drug regimen (including a diuretic). Adherence is a major issue: the rate of partial or complete noncompliance probably approaches 50% in this group of patients; doxazosin, spironolactone, and hydrochlorothiazide were particularly unpopular in one Eastern European study based on drug assay. In the approach to resistant hypertension, the clinician should first confirm compliance and rule out “white coat hypertension,” ideally using ambulatory or home-based measurement of blood pressure. Exacerbating factors should be considered (as outlined above). Finally, identifiable causes of resistant hypertension should be sought (Table 11–14). The clinician should pay particular attention to the type of diuretic being used in relation to the patient’s kidney function. Aldosterone may play an important role in resistant hypertension and aldosterone receptor blockers can be very useful. If goal blood pressure cannot be achieved following completion of these steps, consultation with a hypertension specialist should be considered. Procedure-based approaches to resistant hypertension are being developed, but the Symplicity HTN 3 study failed to show that renal sympathetic ablation improved blood pressure compared to a sham-operated control group. None of the device-based approaches to resistant hypertension have been formally evaluated in controlled, outcomes-based trials and renal artery stenosis linked to renal nerve ablation has been reported. In view of the uncertainties regarding efficacy, these devices have not yet established a place in the management of hypertension in general clinical practice.