OVERVIEW ― Severe hypertension can be classified in to Hypertensive Emergency and Hypertensive Urgency. In Hypertensive Emergency, BP > 180/120 mmHg with target organ damage (new or worsening). Examples include encephalopathy, intracerebral hemorrhage, ischemic stroke, unstable angina, myocardial infarction, left ventricular failure with pulmonary edema, aortic aneurysm dissection, and acute renal failure. Patients might report chest pain shortness of breath; swelling; mental status changes; or speech, vision, or gait changes. Note that patients without target organ damage might still have symptoms (e.g., headache, atypical chest pain, dyspnea, dizziness, lightheadedness, nosebleed).
Hypertensive urgency (some experts prefer “asymptomatic uncontrolled hypertension” or “severe asymptomatic hypertension”), severe blood pressure elevation in a patient who is stable, without actual or impeding impact on target organs. Some experts would handle patients with known aortic or intracranial aneurysms akin to those with emergencies. Note that a blood pressure threshold of > 180/120 mmHg is somewhat arbitrary; also consider baseline blood pressure and rate of increase.
In what settings can severe hypertension be treated? Hypertensive emergency: intensive care setting for continuous BP monitoring and administration of a parenteral antihypertensive. Hypertensive urgency: does not require emergency department or hospital management.
BP GOALS FOR SEVERE HYPERTENSION
What are the BP goals for treatment of severe hypertension? FOR Hypertensive Emergency, Aortic dissection: reduce SBP to ≤ 120 mmHg within the first 20 to 60 min. Pheochromocytoma: reduce SBP to < 140 mmHg within an hour. Acute ischemic stroke: rapidly lowering BP to < 140/90 mm Hg is safe and may be associated with improved radiographic and clinical outcomes. Intracerebral hemorrhage: reduce SBP to < 220 mmHg. Immediate reduction to < 140 mmHg doesn’t help, and may be harmful. For other patients, SBP should be reduced by ≤ 25% within the first hour, then reduce BP to 160/100 mmHg within the next two to six hours if stable. Then reduce to the normal range in the next 24 to 48 hours. Hypertensive urgency: begin/restart/adjust treatment and follow-up in a matter of days. Work toward individualized blood pressure goal with at least monthly follow-up.
TREATMENT
What are the treatment options for hypertensive emergencies? Due to impaired tissue perfusion, the preferred treatment is continuous infusion of a short-acting, titratable antihypertensive to limit target organ damage. No particular agent has been shown in randomized controlled trial (RCT) to improve morbidity or mortality. Consider starting an oral agent 6 to 12 hours after starting parenteral therapy.
What are the treatment options for hypertensive urgencies? Ask about medication adherence, diet (e.g., salt intake), new medications (e.g., NSAIDs), pain, and usual blood pressure. After confirming elevation after 20 to 30 minutes of rest, restart or step-up antihypertensive therapy. Thirty minutes of rest reduces blood pressure to < 180/110 mmHg in a third of patients. Treat anxiety, if applicable. Avoid use of oral antihypertensive loading doses, immediate-release nifedipine, or intravenous medications due to risk of hypotension. In hypertensive urgencies, failure to aggressively reduce blood pressure does not increase risk short-term. In the week after presentation, only 1 in 1,000 patients has a cardiovascular event. Arrange follow-up within 7 days, with phone follow-up in the meantime. Consider earlier follow-up for patients with cardiovascular or renal disease. Patients should be followed at least monthly until blood pressure goal is reached.
What are some patient counseling points or resources pertaining to severe hypertension? Ensure patients are taking their blood pressure correctly to avoid “false alarms” (e.g., advise sitting quietly for five minutes before checking BP, using the correct cuff size, etc).
DRUG OPTIONS FOR HYPERTENSIVE EMERGENCY
| Table (1). Drug options for hypertensive emergency | |||
|---|---|---|---|
| Drug | Adult Dose | A preferred agent in.. | Comments |
| Alpha Blocker | |||
| Phentolamine | 5 mg IV bolus. May repeat every 10 min as needed to meet BP target. | Pheochromocytoma MAOI interactions Cocaine overdose Amphetamine overdose Clonidine withdrawal |
Onset: 1 to 2 min Duration: 10 to 30 min |
| Angiotensin-Converting Enzyme Inhibitor | |||
| Enalaprilat | 1.25 mg IV over 5 minutes. Max dose 5 mg every 6 h. | High plasma renin activity. | Hard to titrate. Unpredictable response. Slow onset (5 to 15 minutes). Duration 4 to 6 hrs. |
| Beta-Blockers | |||
| Esmolol | 500 to 1,000 mcg/kg/min over one minute, then 50 mcg/kg/min. If dosage increase is needed, rebolus and increase by 50 mcg/kg/min. Max 200 mcg/kg/min. |
Acute aortic dissection Acute coronary syndrome |
Avoid in acute pulmonary edema, decompensated heart failure, bradycardia, poor peripheral perfusion, second- or third-degree heart block, or reactive airway disease. Onset: 1 to 2 min; duration: 10 to 30 min |
| Labetalol | 0.3 to 1 mg/kg (max 20 mg) slow IV push every 10 minutes, or 0.4 to 1 mg/kg/h infusion. Max 3 mg/kg/h. Total cumulative dose 300 mg. May repeat every 4 to 6 hours. |
Acute aortic dissection Acute coronary syndrome (esmolol or nitroglycerin preferred) Hyperadrenergic state |
Avoid in acute pulmonary edema, decompensated heart failure, bradycardia, poor peripheral perfusion, second- or third-degree heart block, or reactive airway disease. Caution in cocaine overdose. Onset: 5 to 10 min Duration: 3 to 6 hrs |
| Calcium Channel Blockers | |||
| Clevidipine | 1 to 2 mg/h, doubled every 90 seconds until near BP target, then increased more slowly (less than doubled) every 5 to 10 minutes. Max 32 mg/h. Max duration 72 hours. Dose cautiously in elderly. |
Acute pulmonary edema Acute renal failure States of catecholamine excess |
Avoid in soy or egg allergy, acute pancreatitis, lipoid nephrosis, pathological hyperlipidemia, or other disorders of lipid metabolism. (It is a lipid emulsion) Avoid in acute coronary ischemia due to reflex tachycardia. |
| Nicardipine | 5 mg/h, increased every five minutes by 2.5 mg/h. Max 15 mg/h. | Acute renal failure Acute coronary syndrome (esmolol or nitroglycerin preferred) |
May be preferable to labetalol in regard to achieving short-term BP targets. Avoid in advanced aortic stenosis. Avoid in patients with acute coronary ischemia unless a beta-blocker has already been started. Onset: 5 to 15 min; duration: 30 to 40 min. |
| Dopamine Receptor (D1) Agonist | |||
| Fenoldopam | 0.1 to 0.3 mcg/kg/min, increased by 0.05 to 0.1 mcg/kg/min every 15 min. Max 1.6 mcg/kg/min. | Acute renal failure | Avoid in patients at risk of increased intraocular pressure (glaucoma) or increased intracranial pressure. Avoid in sulfite allergy. Onset: 5 to 15 min; duration: 30 to 60 min. |
| Vasodilators | |||
| Nitroglycerin | 5 mcg/min, increased by 5 mcg/min every three to five min. Max 20 mcg/min. | Acute coronary syndrome Acute pulmonary edema |
Avoid in volume-depleted patients. Can cause serious hypotension in patients taking phosphodiesterase-5 inhibitors (e.g., sildenafil). Onset: 1 to 5 min; duration: 3 to 5 min |
| Sodium nitroprusside | 0.3 to 0.5 mcg/kg/min, increased by 0.5 mcg/kg/min every 5 min to target BP. Max 10 mcg/kg/min. Dose cautiously in elderly. Discontinue as soon as possible due to risk of cyanide toxicity and tachyphylaxis. |
Acute pulmonary edema | Should be used with intra-arterial blood pressure monitoring. Consider use of sodium thiosulfate for infusion rates ≥ 4 to 10 mcg/kg/min or duration > 30 min. Renal impairment increases risk of thiocyanate toxicity, and liver impairment increases the risk of cyanide toxicity. Increases intracranial pressure. May cause dose-dependent methhemoglobinemia. Onset immediate; duration: 1 to 2 min |
| Hydralazine | 10 to 20 mg slow IV bolus. Repeat every 4 to 6 hours as needed. | Not desirable for most patients due to unpredictable and prolonged response. May worsen coronary ischemia. |
Onset: 10 to 30 minutes; duration: 2 to 4 hours. |
REFERENCES
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Whelton, Williamson, J.D. and Wright, J.T. (2018). 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension, 71(6). Available at: https://pubmed.ncbi.nlm.nih.gov/29133356
Shayne, P.H. and Pitts, S.R. (2003). Severely increased blood pressure in the emergency department. Annals of Emergency Medicine, 41(4), pp.513–529
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