Resistant Hypertension Management

Resistant hypertension:

 

Resistant hypertension is defined as blood pressure that remains above target despite the use of three antihypertensive medications at optimal doses, including a diuretic, or when four or more drugs are needed to control it.

🧠 Key Criteria

Confirmed diagnosis:

Office BP ≥140/90 mmHg (or ≥130/80 mmHg in diabetics) despite ≥3 drugs, one of which is a diuretic.

OR controlled BP but requiring ≥4 medications.

True vs. pseudo-resistance:

Rule out poor adherence, incorrect BP measurement, white coat effect, and suboptimal drug dosing.

🔍 Why it matters

Resistant hypertension is a red flag for:

Secondary causes (e.g., primary aldosteronism, renal artery stenosis, obstructive sleep apnea, pheochromocytoma).

End-organ damage (e.g., LVH, CKD, retinopathy).

Increased cardiovascular risk (stroke, MI, heart failure).

It requires a structured evaluation to rule out secondary causes, optimize therapy, and assess end-organ damage. Labs should target renal, endocrine, and cardiovascular systems. Management includes lifestyle, pharmacologic intensification, and specialist referral.

🧪 Stepwise Evaluation: Labs and Diagnostics

Confirm true resistance:

Ensure adherence, correct BP measurement, and exclude white coat effect (ambulatory BP monitoring).

Basic labs:

Electrolytes, BUN, creatinine: assess renal function.

eGFR and urine albumin-to-creatinine ratio: screen for diabetic nephropathy.

HbA1c, fasting glucose: glycemic control.

Lipid panel: cardiovascular risk.

Secondary hypertension workup:

Renin and aldosterone levels: screen for primary aldosteronism (especially if hypokalemia).

TSH: rule out hypothyroidism.

24-hour urinary metanephrines or plasma free metanephrines: pheochromocytoma.

Sleep study: if clinical suspicion of obstructive sleep apnea.

Renal artery Doppler or CTA/MRA: if renal artery stenosis suspected.

Cardiac evaluation:

ECG: LVH or ischemia.

Echocardiogram: LV function, hypertrophy, diastolic dysfunction.

💊 Pharmacologic Management

Triple therapy must include a diuretic:

Thiazide-like diuretics (chlorthalidone or indapamide) preferred over hydrochlorothiazide.

If eGFR <30, switch to loop diuretic (e.g., furosemide).

Optimize other agents:

ACE inhibitor or ARB (especially in DM with albuminuria).

Calcium channel blocker (e.g., amlodipine).

Beta-blocker only if compelling indication (CAD, heart failure).

Add-on options:

Mineralocorticoid receptor antagonist (spironolactone or eplerenone): effective in resistant HTN, especially if aldosterone excess.

Alpha-blockers (e.g., doxazosin): useful in BPH.

Central agents (e.g., clonidine): last resort due to side effects.

🧠 Lifestyle and Specialist Referral

Lifestyle:

Sodium restriction <2.3 g/day.

Weight loss, DASH diet, physical activity.

Limit alcohol, smoking cessation.

Referral:

Endocrinology: if secondary cause suspected.

Nephrology: if CKD or r

enal artery stenosis.

Sleep medicine: if OSA suspected.