• Follow guideline for number that is most out of range
Blood pressure reading (mmHg) Follow-up
< 120 / 80 Recheck in 2 years
120 - 139 / 80 - 89 Recheck in 1 year
140 - 159 / 90 - 99 Recheck within 2 months
160 - 179 / 100 - 110 Recheck within 1 month
≥ 180 / ≥ 110 Treat now or recheck within 1 week

  • Arm circumference should be measured at the midpoint of the acromion and olecranon
Arm circumference (cm) Cuff size
22 - 26 Small adult
(size 12X22 cm)
27 - 34 Standard adult
(size 16X30 cm)
35 - 44 Large adult
(size 16X36 cm)
45 - 52 Extra-large adults (thigh cuff)
(size 16X42 cm)

  • Reference [1,2,47,51]
Proper BP measurement technique
Measurement preparation
  • Relax for 3 - 5 minutes while sitting in a chair with feet flat on floor (legs uncrossed) and back supported. Do not talk to anyone during this period.
  • Caffeine, exercise, and smoking should be avoided ≥ 30 minutes prior to measurement
  • Patient should empty bladder before measurement if necessary
  • The arm should be bare if possible, but a shirtsleeve should not be rolled up if it is too tight because it may act as a tourniquet
  • If back is not supported, SBP and DBP may be increased by 5 – 15 and 6 mm Hg, respectively
  • Having legs that are crossed during BP measurement may raise SBP by 5 – 8 mm Hg and DBP by 3 – 5 mm Hg
Measurement technique
  • Use upper arm cuff
  • Arm should be supported (e.g. resting on a table), but not by the patient
  • Position the middle of the cuff on the upper arm at the level of the right atrium (midpoint of the sternum)
  • Use correct cuff size (see cuff size above)
  • If the upper arm is below the level of the right atrium (eg, when the arm is hanging down while in the seated position), the readings will be too high
  • The cuffed arm should be held up by the observer or resting on a table at heart level. If the arm is held up by the patient, BP will be raised
Measurement frequency
  • At first clinic visit or reading, measure blood pressure on both arms. Arm that gives the highest reading should be used from then on.
  • At least 2 measurements should be made (at least 1 minute apart), and the average should be used
  • If taking BP medication, take 2 readings in the morning before taking meds and two readings in the evening
  • Use average of ≥ 2 readings on ≥ 2 separate occasions to estimate BP. Ideally, BP monitoring period will be ≥ 7 days.
  • Persistent BP differences between arms of ≥ 10 mmHg are common and occur in 11.2% of people with hypertension and about 4% of the general population. Significant BP arm differences can be a sign of coarctation of the aorta (see secondary causes above), but this condition is rare (0.1% of patients with hypertension).
  • A study that included over 38,000 patients found that on average, the median change in clinic SBP on a second reading among patients with hypertension who had a high initial reading was -8 mmHg. [PMID 29710186]
  • In another study, 35% of people with a BP measurement of 140 - 159/90 - 99 mm Hg on their first measurement, had a BP < 140/90 mm Hg when the average of 3 measurements was used [51]

  • Percentages represent prevalence among patients with hypertension
Causes of secondary hypertension
Obstructive sleep apnea (25 - 50%)
  • Signs and symptoms: snoring; daytime sleepiness; obesity; apnea during sleep
  • Diagnosis: sleep study
Renal vascular disease (5 - 34%)
  • Signs and symptoms: resistant hypertension; hypertension of abrupt onset; young females (fibromuscular hyperplasia); abdominal bruit
  • Diagnosis: renal doppler ultrasound; MRA/CT
  • Treatment: A randomized controlled trial found no benefit of renal artery stenting in atherosclerotic renal artery stenosis (see renal artery stenosis below)
Primary aldosteronism (8 - 20%)
  • Signs and symptoms: resistant hypertension with hypokalemia
  • Diagnosis: aldosterone / renin ratio
Drugs and alcohol (2 - 4%)
Renal parenchymal disease (1 - 2%)
  • Signs and symptoms: family history of polycystic kidney disease; abnormal urinalysis; elevated serum creatinine
  • Diagnosis: renal ultrasound
Aortic coarctation (0.1%)
  • Signs and symptoms: young patient (< 30 years) with hypertension; BP higher in upper extremities than in lower extremities; absent femoral pulses
  • Diagnosis: Echocardiogram
Cushing's syndrome (rare, < 0.1%)
  • Signs and symptoms: central obesity; moon face; supraclavicular fat pads; violaceous striae, hirsutism
  • Diagnosis: see HPA axis testing
Hyper / hypothyroidism (rare, < 0.1%)
  • Signs and symptoms: depends on cause
  • Diagnosis: TSH
Primary hyperparathyroidism (rare)
  • Signs and symptoms: none
  • Diagnosis: Serum calcium
Pheochromocytoma (rare, 2 - 8 cases per million persons annually) [27]
  • Signs and symptoms: resistant hypertension; paroxysmal hypertension with headache, sweating, palpitations, and pallor
  • Diagnosis: 24-hour urinary fractionated metanephrines or plasma metanephrines; CT/MRI of adrenals [47]
Congenital adrenal hyperplasia (rare)
  • Signs and symptoms: virilization or incomplete masculinization
  • Diagnosis: Newborn screening, hormone studies
Acromegaly (rare)
  • Signs and symptoms: large hands, feet, head
  • Diagnosis: Growth hormone level

  • Reference [50]
AHA 2018 recommendations for treating resistant hypertension
(Start with Step 1. Proceed to next step if BP does not reach target.)
Step 1
  • Ensure that patient meets definition
  • Maximize lifestyle interventions
    • Low sodium diet (< 2400 mg/day)
    • ≥ 6 hours of uninterrupted sleep
    • Weight loss and exercise
Step 2
Step 3
Step 4
Step 5
  • Add hydralazine 25 mg three times a day and titrate
  • Patients with heart failure and reduced EF should receive isosorbide mononitrate with hydralazine
  • Because of side effects (edema, tachycardia), hydralazine should be given with a beta blocker and loop diuretic
Step 6
  • Substitute minoxidil 2.5 mg two to three times a day for hydralazine and titrate
  • Because of side effects (edema, tachycardia), minoxidil should be given with a beta blocker and loop diuretic

Lifestyle change Goal Approximate SBP reduction
Weight loss Maintain BMI 18 - 25 5 - 20 mmHg depending on starting weight
Adopt DASH diet Consume diet rich in fruits, vegetables, and low-fat dairy products 8 - 14 mmHg
Decrease sodium
(see sodium below)
Decrease daily sodium intake to ≤ 2400 mg 2 - 8 mmHg
Increase exercise At least 30 minutes a day, 5 days a week 4 - 9 mmHg
Moderate alcohol consumption No more than 2 drinks a day for males, and 1 drink a day for females 2 - 4 mmHg
Increase potassium intake 4 - 5 servings of fruits and vegetables will usually provide 1500 to >3000 mg (38 to >77 mEq) of potassium per day 4 - 5 mmHg
Stop smoking ∼7 mmHg [1,5,6,47]

Medication class Compelling indication
ACE inhibitors diabetes, heart failure, kidney disease
Aldosterone antagonists heart failure, liver failure, resistant hypertension, acne
ARBs diabetes, heart failure, kidney disease
Alpha-2 agonists hypertensive urgency
Alpha blockers benign prostatic hyperplasia
Beta blockers heart failure, heart attack, angina, atrial fibrillation, esophageal varices
Calcium channel blockers angina, atrial fibrillation (nondihydropyridines), black patients
Loop diuretics heart failure, kidney failure, liver failure
Thiazide diuretics heart failure, calcium-based kidney stones, black patients
Vasodilators angina, heart failure, resistant hypertension

  • Renal artery stenosis is narrowing of the arteries that perfuse the kidneys. It is typically caused by atherosclerotic vascular disease but may also occur secondary to fibromuscular dysplasia (more common in women < 50 years old)
  • Renal artery stenosis can lead to resistant hypertension and decreased kidney function. Revascularization with stent placement has been used for years to treat renal artery stenosis despite clear evidence that it is beneficial.
  • The CORAL trial detailed below was specifically designed to evaluate what benefit, if any, that stenting has over medical therapy alone.
CORAL Trial - Renal Artery Stenting + Medical Therapy vs Medical Therapy, NEJM (2014) [PubMed abstract]
  • The CORAL trial enrolled 947 patients with atherosclerotic renal artery stenosis
Main inclusion criteria
  • Severe renal artery stenosis (defined as ≥ 80%; or ≥ 60% with a systolic pressure gradient of at least 20 mmHg)
  • SBP ≥ 155 mm Hg while receiving ≥ 2 BP meds OR GFR < 60 ml/min
Main exclusion criteria
  • Fibromuscular dysplasia
  • Chronic kidney disease other than ischemic nephropathy
  • Serum creatinine > 4 mg/dl
  • Vascular lesion requiring more than one stent
Baseline characteristics
  • Average age 69 years
  • Average systolic BP - 150 mmHg
  • Average GFR - 58 ml/min
  • Average % stenosis - 67%
  • Bilateral stenosis - 20%
Randomized treatment groups
  • Group 1 (459 patients): Renal artery stent + medical therapy
  • Group 2 (472 patients): Medical therapy alone
  • Medical therapy consisted of antiplatelet therapy, candesartan, amlodipine, atorvastatin, and HCTZ if needed
  • Target blood pressure was < 140/90 in general, and < 130/80 in patients with diabetes or chronic kidney disease
Primary outcome: Composite of death from cardiovascular or kidney causes, stroke, heart attack, hospitalization for congestive heart failure, progressive kidney disease, or the need for permanent kidney-replacement therapy

Duration: Median of 43 months
Outcome Stent None Comparisons
Primary outcome 35.1% 35.8% HR 0.94, 95%CI [0.76 - 1.17], p=0.58
Overall mortality 13.7% 16.1% HR 0.80, 95%CI [0.58 - 1.12], p=0.20
Progressive kidney disease (defined as 30% reduction in GFR) 16.8% 18.9% HR 0.86, 95%CI [0.64 - 1.17], p=0.34
  • Average SBP was slightly lower in the Stent group (diff -2.3 mmHg, p=0.03)

Findings: Renal-artery stenting did not confer a significant benefit with respect to the prevention of clinical events when added to comprehensive, multifactorial medical therapy in people with atherosclerotic renal-artery stenosis and hypertension or chronic kidney disease.
AHA 2017 recommendations
  • Medical therapy is recommended for adults with atherosclerotic renal artery stenosis
  • In adults with renal artery stenosis for whom medical management has failed (refractory hypertension, worsening renal function, and/or intractable heart failure) and those with nonatherosclerotic disease, including fibromuscular dysplasia, it may be reasonable to refer the patient for consideration of revascularization (percutaneous renal artery angioplasty and/or stent placement) [47]
StraightHealthcare analysis
  • In the CORAL trial detailed above, renal artery stenting did not improve outcomes in patients with atherosclerotic renal artery stenosis
  • Stenting has not been studied extensively in other types of renal artery stenosis (e.g. fibromuscular dysplasia), and its effects on these conditions is unknown

Beetroot juice and nitric oxide
  • Nitric oxide is a potent vasodilator produced by endothelial cells
  • Nitric oxide is formed from the reduction of nitrite, and nitrite is formed from the reduction of nitrate
  • Nitrates consumed in the diet are converted to nitric oxide through a multistep process
  • Dietary nitrates are absorbed through the small intestine. The nitrates are then extracted from the blood by the salivary glands and secreted into the oral cavity. Bacteria in the oral cavity reduce nitrates to nitrites. Nitrites are swallowed and absorbed into the circulation where they come into contact with nitrite reductase. Nitrite reductase converts nitrites to nitric oxide. [45]
  • Beetroot juice has a very high nitrate concentration (∼6 mmol per 250ml)
  • A study published in 2015 compared beetroot juice to placebo for blood pressure lowering
Beetroot juice vs Placebo for Hypertension, Hypertension (2015) [PubMed abstract]
  • The study enrolled 68 patients with hypertension
Main inclusion criteria
  • Age 18 - 85 years
  • Ambulatory daytime BP > 130/85 mmHg
  • BMI 18 - 40
Main exclusion criteria
  • History of CVD
  • CrCl < 50 ml/min
  • History of heart failure
Baseline characteristics
  • Average age 56 years
  • Average ambulatory BP - 148/88
  • Average # of Hypertension drugs - 1
Randomized treatment groups
  • Group 1 (32 patients): Beetroot juice 250 ml (∼6.4 mmol of nitrates) every morning for 4 weeks
  • Group 2 (32 patients): Nitrate-depleted beetroot juice for 4 weeks
  • Half the randomized patients were drug-naïve and half were receiving hypertension meds
  • The study included a 2-week run-in phase in which baseline BP was assessed. The study also included a 2-week post-treatment phase where BP was assessed again.
Primary outcome: Change in clinic, ambulatory, and home BP compared with placebo

Duration: 4 weeks
Outcome Beetroot juice Placebo Comparisons
Change in ambulatory BP (SBP / DBP) -6.6 / -4.3 mmHg +0.8 / +0.9 mmHg p<0.001
Change in clinic BP (SBP / DBP) -8.7 / -3.2 mmHg -1 / -0.7 mmHg p<0.001
  • Home BP was significantly reduced in Group 1 compared to Group 2 (Group 1 minus Group 2: SBP -8.1 mmHg, DBP -3.8 mmHg)
  • Markers of endothelial function and arterial stiffness were also significantly improved in Group 1 when compared to Group 2
  • There was no evidence of methemoglobinemia or tachyphylaxis (sudden loss of effect) in Group 1
  • Discoloration of the urine and feces was common (known side effect of beets)

Findings: These findings suggest a role for dietary nitrate as an affordable, readily-available, adjunctive treatment in the management of patients with hypertension
StraightHealthcare analysis
  • This study is interesting because it found that beetroot juice lowers blood pressure
  • Beetroot juice may be the only dietary treatment ever proven to lower blood pressure in a randomized controlled trial
  • The long-term efficacy and side effects of consuming daily beetroot juice are unknown