Resistant arterial hypertension (RAH) is defined, according to the American Heart Association Scientific Position of 2018, as well as observed in the I Brazilian Position of RAH in 2012, when an individual’s blood pressure (BP) remains elevated above the blood pressure target, in spite of the use of three antihypertensive drugs of different therapeutic classes, commonly a long-acting dihydropyridine slow-calcium-channel antagonist drug; a renin-angiotensin-aldosterone system (RAAS) blocker, which may be an angiotensin II converting-enzyme inhibitor or angiotensin II AT₁ receptor blocker; and an appropriate diuretic, all administered at the maximum doses or at the highest possible tolerated doses, and in accordance with the prescribed administration intervals. These patients are considered to be at greater risk of cardiovascular and renal morbidity and mortality; more likely to have adverse events in response to drug therapy, usually dose-related; a secondary cause of hypertension should be ruled out in this group of individuals, because its prevalence is significantly higher than in the nonresistant hypertensive population.^, The controlled RAH is also currently recognized as that in which patients using four or more medications reached the blood pressure target; and refractory AH, an entity that has a different pathophysiology from RAH, when even the four drugs are not enough to control it. According to this new classification, patients with pseudohypertension should be excluded, that is, it is mandatory for diagnostic confirmation to verify adherence and tolerance to medication; to rule out white-coat hypertension; and thus, it is crucial to perform systematized blood pressure measurements outside the office environment through Ambulatory BP Monitoring (ABPM) or Home BP Measurement (HBPM); and finally, the use of a correct and reliable BP measurement technique.^,,,

Even in primary AH, the existence of a systemic inflammatory process, albeit a subclinical one, is recognized and this condition has been identified with higher intensity in cardiovascular and renal diseases, such as RAH and chronic kidney disease. Specifically in the case of RAH, which is a multifactorial and polygenic entity, often associated with metabolic diseases that occur with insulin resistance, such as diabetes and obesity, inflammatory processes promoted by mediators may be involved, leading to the important endothelial dysfunction of the microvasculature and increased oxidative stress.

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