GENERAL THERAPIES / HYPERTENSION

Hypertensive crisis

Created 03/11/2022, last revision 06/07/2023

Definition

a hypertensive crisis is a medical emergency characterized by a sudden and severe elevation in blood pressure
- the levels of hypertension are not universally established and are arbitrary (usually > 180/120 mmHg)
- the rate of BP elevation seems more important than its absolute value
- the term crisis gets abandoned in favor of the following terms
the presence of a target-organ lesion distinguishes:
- hypertensive urgency – without target-organs damage
- hypertensive emergency – with acute target-organs complications (heart, kidneys, brain, eyes)
hypertensive crisis has a mortality rate of up to 7% (Katz, 2009)

Etiology

decompensation of chronic hypertension
- most commonly caused by sudden discontinuation of antihypertensive medication or drug interactions
- perioperative
- acute stroke (which may be a cause or a result of uncontrolled hypertension)
secondary hypertension
- pheochromocytoma
- preeclampsia/eclampsia
- abuse of sympathomimetic drugs (amphetamine, LSD, cocaine)

Clinical presentation

cerebrovascular
- hypertensive encephalopathy (confusion, headaches, nausea/vomiting, visual disturbances, seizures)
  - symptoms of hypertensive encephalopathy resolve after blood pressure is lowered and autoregulation of cerebral flow is restored
- posterior reversible encephalopathy syndrome (PRES)
- intracerebral hemorrhage (focal symptoms)
- subarachnoid hemorrhage (headache, meningeal syndrome)
cardiovascular (chest pain, shortness of breath)
- acute left-sided heart failure (dyspnea, pulmonary edema)
- acute MI/unstable AP
- acute aortic dissection (acute and severe chest or back pain)
renal
- acute renal failure
eye symptoms
- hemorrhages, exudates, or edema of the papillae (signs of hypertensive retinopathy grade III or IV) are associated with hypertensive encephalopathy

Diagnostic evaluation

repeated BP measurement or continuous BP monitoring
- start by measuring both arms’ blood pressure (aortic dissection or coarctation, subclavian artery stenosis)
- if aortic dissection is suspected, also measure BP in the lower limbs
look for organ damage
- blood samples
  - CBC + coagulation
  - renal and hepatic tests
  - NT-proBNP (heart failure)
  - cardiac enzymes (in suspected ACS)
  - urine chemistry and urine sediment examination
  - D-dimers (when aortic dissection is suspected)
- ECG
- brain CT + CTA (in patients with acute neurological complaints/signs or case of head injury)
- chest x-ray (in patients with shortness of breath)
- CTA of the chest and abdomen for suspected aortic dissection
- fundoscopic exam (ophthalmoscopy)
exclude secondary hypertension
- CT/MR angiography of renal arteries (renovascular hypertension)
- plasma renin activity (PRA) and aldosterone, plasma or urine metanephrines

Blood pressure monitoring

arterial blood pressure (BP) monitoring is a mainstay of hemodynamic monitoring in neurocritical care
both hypotension and hypertension can impair vital organ function and worsen the outcome
BP monitoring techniques:
- non-invasive BP monitoring (more common)
  - intermittent (inflatable cuff) – the proper cuff size is critical
    - manual (auscultatory, palpatory)
    - automated (oscillometric)
  - continuous
    - volume clamp method
    - arterial applanation tonometry
- invasive BP measurement via arterial cannulation (most commonly automated)
choice of BP monitoring must be individualized
- low-risk patients – intermittent oscillometric BP monitoring
- high-risk, hemodynamically unstable patients – continuous BP monitoring (noninvasive or invasive)
- critically ill patients/hypertensive emergencies – continuous invasive BP monitoring via an arterial catheter is preferred

Proper cuff size

the cuff bladder length should be at least 80% of the upper arm circumference
- arm circumference < 35 cm – cuff 16×30 cm (suitable for most patients)
- arm circumference 35-44 cm – cuff 16×36 cm
- arm circumference > 45 cm – cuff 16×42 cm

Preeclampsia and eclampsia

preeclampsia = new onset hypertension >140/90 mmHg + proteinuria > 500 mg/24 h or 300 mg/l occurring after 20 weeks gestation or during the second half of pregnancy
- most commonly occurs during the 3rd trimester of pregnancy and may occur before, during, or after delivery
eclampsia = elevated BP associated with seizures, multi-organ damage (aspiration pneumonia, cerebral hemorrhage, kidney failure, pulmonary edema, HELLP syndrome), and coagulopathy

Classification

The severity of a hypertensive crisis depends on:

current BP values
presence of acute target-organ damage
rate of BP increase (how long it took for BP to increase from the baseline values to the current values)

Hypertensive emergency

life-threatening condition
hypertension + signs of organ damage
- hypertensive encephalopathy (incl. hyperperfusion syndrome following revascularization procedures – CEA, CAS)
- cardiac failure +/- pulmonary edema
- acute coronary syndrome (ACS)
- aortic dissection
- SAH/ICH
etiology
- discontinuation of chronic antihypertensive medication
- pre-/eclampsia
- pheochromocytoma crisis
requires aggressive parenteral therapy

Hypertensive urgency

not a life-threatening condition; no signs of organ damage (provoked by acute BP elevation)
usually results from the decompensation of chronic hypertension
- decompensation during invasive procedures, panic attacks, or after administration of psychoactive substances (cocaine, meth)
it can usually be managed on an outpatient basis
use oral medications and lower the blood pressure within 24 h

Management of hypertensive emergency

admission + monitoring of vital signs (incl. continuous BP monitoring)
use analgesia or sedation if needed
assess for target organ injury + start parenteral medications (rapid BP lowering is the mainstay of therapy)
except for aortic dissection, avoid excessive BP reduction (⇒ risk of cerebral and myocardial hypoperfusion, provocation of arrhythmias, etc.)
- reduce mean BP by 20-25% in the first hour, then to 160/100 mm Hg over the next 2-6 hours, and then gradually to baseline values over 2 days
- aortic dissection: reduce SBP to < 100-120 mmHg + reduce heart rate to < 60/min within 20 min
use fast-acting and easily titratable antihypertensive drugs – parenteral drugs allow bolus administration + continuous infusion
- in patients with significant tachycardia, metoprolol or clonidine (which also has a sedative effect) are appropriate BP-lowering drugs
- in pregnancy, IV hydralazine or oral nifedipine may be used (avoid ACE inhibitors or ARBs)
- avoid nitrates in patients with intracranial hypertension
start specific treatment of affected organs

Hypertensive emergency	Medication
acute MI / unstable angina	*nitroglycerin* or isosorbide dinitrate (ISOKET) metoprolol (BETALOC) bolus 1,25–5 mg IV / esmolol (ESMOCARD, BREVIBLOC) + urapidil (EBRANTIL)
acute left-sided heart failure	loop diuretics + vasodilators nitroglycerine 1-10 mg/h / ISOKET + FUROSEMIDE (20-40mg) enalapril (ENAP)
aortic dissection	esmolol (ESMOCARD, BREVIBLOC) nebo metoprolol (BETALOC) nitroprusid (NIPRUSS) (+ propanol) reduce SBP to < 100–120 mm Hg + HR < 60/min within 20 minutes
hypertensive encephalopathy	*labetalol (TRANDATE)* / urapidil (EBRANTIL) / esmolol (ESMOCARD, BREVIBLOC) enalapril (ENAP)
ICH → BP management in an acute stroke	urapidil (EBRANTIL) / *labetalol (TRANDATE)*
SAH	nimodipine (DILCEREN) / urapidil (EBRANTIL)
pheochromocytoma abuse of the sympathomimetic drug	urapidil (EBRANTIL) / isosorbide dinitrate (ISOKET) / *labetalol (TRANDATE*)
preeclampsia/eclampsia	*labetalol (TRANDATE) / nitropruside (NIPRUSS)* hydralazine i.v. (2.5–20 mg in eclampsia with the insufficient effect of labetalol)
renal insufficiency	urapidil (EBRANTIL) / furosemide (20-40mg)
rebound after discontinuing beta-blockers	metoprolol (BETALOC)