Resistant hypertension: What to do after trying 'the usual'

Hypertension is considered to be 'resistant' if a patient's diastolic blood pressure remains above 90 mm Hg despite the use of full doses of three antihypertensive medications. The most likely causes of ineffective blood pressure control include inadequate drug regimens and patient factors such as noncompliance, obesity, cigarette smoking, alcoholism, and 'office hypertension.' The two most common physiologic causes of resistance are volume overload and secondary hypertension, particularly renovascular disease. When suspicion of renovascular hypertension is high, immediate renal arteriography is indicated. In most patients, however, the less invasive captopril challenge is an adequate screening test. Most hypertensive patients with true resistance can be treated by altering their medication regimen.