Resistant hypertension represents a specific clinical diagnosis distinct from typical high blood pressure. This condition is characterized by blood pressure that remains above target levels despite a treatment regimen involving three or more antihypertensive medications from different classes, all administered at their optimal or maximally tolerated doses. A diuretic medication must be included as one of these agents for the diagnosis to be considered. Alternatively, blood pressure that is controlled but requires four or more different antihypertensive drugs also falls under this definition.
Confirming the Diagnosis and Investigating Causes
Before a diagnosis of resistant hypertension is confirmed, healthcare providers first investigate factors that can make blood pressure appear higher than it truly is, known as pseudoresistance. Inaccurate blood pressure measurement techniques, such as using an improperly sized cuff or incorrect patient positioning, can lead to falsely elevated readings. The “white coat effect,” where blood pressure is elevated only in a clinical setting but normal outside of it, also contributes to pseudoresistance and requires out-of-office monitoring. Furthermore, poor adherence to prescribed medications, often due to forgetfulness or side effects, can mimic true resistance.
Once pseudoresistance is ruled out, the focus shifts to identifying underlying medical conditions, known as secondary causes, that contribute to elevated blood pressure. Obstructive sleep apnea, characterized by repeated breathing interruptions during sleep, is a common secondary cause that raises blood pressure. Primary aldosteronism, a hormonal disorder of excess aldosterone production, also contributes by promoting sodium and water retention. Chronic kidney disease often presents with hypertension that is difficult to control, as impaired kidney function affects fluid balance and blood pressure regulation. Other less common but important causes include renal artery stenosis, a narrowing of the arteries supplying the kidneys, and certain medications or supplements that can elevate blood pressure.
Optimizing Medication and Lifestyle Strategies
Managing resistant hypertension often begins with a thorough review and optimization of the patient’s existing medication regimen. This involves ensuring all prescribed antihypertensive drugs are at maximum tolerated doses and the combination is appropriate for the individual’s needs. The addition of a fourth medication, particularly a mineralocorticoid receptor antagonist (MRA), is a common next step when blood pressure remains uncontrolled.
Mineralocorticoid receptor antagonists, such as spironolactone and eplerenone, work by blocking the action of aldosterone, a hormone causing sodium and water retention. By inhibiting aldosterone’s effects on the kidneys, these medications increase the excretion of sodium and water, reducing blood volume and lowering blood pressure. This mechanism also helps to spare potassium, preventing its loss. Spironolactone has demonstrated effectiveness as an add-on therapy for resistant hypertension.
Intensified lifestyle modifications play a substantial role alongside medication adjustments. Adopting a very low sodium diet, aiming for less than 1,500 milligrams per day, is particularly important as excessive sodium intake contributes to fluid retention and higher blood pressure. Regular aerobic exercise, typically 30 to 45 minutes performed three times per week, has been shown to lower blood pressure. Limiting alcohol consumption and achieving weight loss for those who are overweight or obese also contribute significantly to better blood pressure control. These lifestyle changes can be challenging but offer meaningful reductions in blood pressure and improved cardiovascular health.
Advanced Interventional Therapies
When optimized medication and lifestyle strategies are insufficient to control blood pressure, advanced interventional therapies may be considered. One such procedure is renal denervation, a minimally invasive treatment targeting overactive nerves in the kidney arteries. This procedure typically uses radiofrequency or ultrasound energy delivered via a catheter inserted into the femoral artery to ablate these nerves.
The goal of renal denervation is to reduce the heightened sympathetic nerve activity that contributes to hypertension; disrupting these nerve signals can decrease blood pressure. Renal denervation is an approved treatment in some regions for unresponsive hypertension. Another investigational procedure is baroreceptor activation therapy, which involves implanting a small device, similar to a pacemaker, near the carotid artery in the neck. This device electrically stimulates baroreceptors, specialized pressure sensors that regulate blood pressure. This stimulation reduces sympathetic nervous system activity and increases vagal activity, both contributing to lower blood pressure.
Assembling a Specialized Care Team
Managing resistant hypertension often requires a collaborative, specialized healthcare team, beyond the primary care physician. Given the complexity of the condition, referral to specialists is recommended if blood pressure goals are not met after several months of therapy.
A cardiologist, specializing in heart conditions, contributes expertise in managing cardiovascular risks. A nephrologist, specializing in kidney diseases, is often a central figure in the care team, as chronic kidney disease is a common cause of resistant hypertension. An endocrinologist, specializing in hormonal disorders, plays a role if conditions like primary aldosteronism are identified. This multidisciplinary approach ensures thorough investigation of potential causes and a tailored treatment plan for achieving blood pressure control.