Resistant Hypertension

Resistant hypertension is defined in JNC 7 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). In this situation, the clinician should first exclude potential identifiable causes of hypertension (Table 11-3), and then carefully explore reasons why the patient might not be at goal blood pressure (Table 11-11). The clinician should pay particular attention to the type of diuretic being used in relation to the patient's renal function. If goal blood pressure cannot be achieved by these measures, consultation with a hypertension specialist should be considered.

Resistant hypertension is high blood pressure that does not respond to treatment. Specifically, resistant hypertension is defined as blood pressure that remains elevated above treatment goals despite administration of an optimal three drug regimen that includes a diuretic. Because some cases of high blood pressure are difficult to treat, and may require a combination of multiple drugs before control is established, high blood pressure cannot be called “resistant” until this three-drug combination therapy has failed.

How is Resistant Hypertension Diagnosed?

Resistant hypertension is diagnosed when the blood pressure continues to be elevated despite trying combination therapy with three drugs. The standard guidelines state that:

* Proper blood pressure measurement technique must be used
* The size of the blood pressure cuff should be double checked for accuracy
* The blood pressure readings must be recorded on two separate occasions

What Causes Resistant Hypertension?

There are many things that can cause resistant hypertension, and proper medical testing is required to investigate each of these potential causes. The three most common causes of resistant hypertension are:

* Patient noncompliance with treatment
* Secondary hypertension (Usually from overactive adrenal glands)
* Fluid retention (usually expansion from kidney failure)

Additionally, it is important to make sure that what appears to be resistant hypertension isn’t actually pseudohypertension or white coat hypertension.

The most common cause of resistant hypertension, and the most difficult to treat, is what medical researchers commonly refer to as "patient noncompliance." The term "patient noncompliance" refers to instances where patients are not adherent to the prescribed treatment, but is not meant to imply the patient is always to blame. To the contrary, most cases of "noncompliance" actually indicate that circumstances not in the patient's control have made following the recommended therapy either impractical or intolerable.