Hypertension: Diagnosis and Treatment


Hypertension is a very common condition, affecting around 30% of all US adults. Most of the cases (~95%) are from primary hypertension, with secondary hypertension being responsible for 5% of the cases.

Risk factors for essential hypertension include age, family history, obesity, race (more common in blacks), alcohol consumption, high-sodium intake and sedentary lifestyle.

The impacts of hypertension on health are substantial because it is an important risk factor for cardiovascular disease (heart failure, stroke, MI, left ventricular hypertrophy) and chronic kidney disease.

CLASSIFICATIONS AND DEFINITIONS:

Patients can be classified according to the levels of his systolic blood pressure (SBP) or diastolic blood pressure (DBP).

In American studies, traditionally, blood pressure levels can be classified as:

Normal BP: SBP <120 mmHg and DBP <80 mmHg
Prehypertension: SBP 120-139 mmHg or DBP 80-89 mmHg
Stage 1 hypertension: SBP 140-159 mmHg or DBP 90-99 mmHg
Stage 2 hypertension: SBP ≥ 160 mmHg or DBP ≥ 100 mmHg

In European studies a different classification may be used:

Optimal BP: SBP < 120 mmHg and DBP <80 mmHg
Normal BP: SBP 120-129 mmHg or DBP 80-84 mmHg
High-normal: SBP 130-139 mmHg or DBP 85-89 mmHg
Grade 1 Hypertension: SBP 140-159 mmHg or DBP 90-99 mmHg
Grade 2 Hypertension: SBO 160-179 mmHg or DBP 100-109 mmHg
Grade 3 hypertension: SBP ≥ 180 mmHg or DBP ≥ 110 mmHg

Other relevant nomenclature that is mostly accepted all around the world:

Isolated systolic hypertension: SBP ≥ 140 mmHg with normal DBP.

White coat hypertension: Blood pressure that is high when measured in a medical care facility but normal elsewhere.

Masked hypertension: Blood pressure that is normal when measured in a medical care facility, but elevated out of the facility.

Hypertensive emergency: Large elevations in SBP or DBP (>180 mmHg or >120 mmHg, respectively) associated with impending or progressive organ dysfunction.

Hypertensive urgency: Very high levels of BP (SBP ≥ 180 mmHg or DBP ≥ 110 mmHg) in an asymptomatic patient.

DIAGNOSIS:

In a patient that presents with a BP ≥ 180/110 mmHg or with hypertensive emergency, the diagnosis of hypertension can be made right away. But these cases are rare. Most cases of hypertension are asymptomatic and detected through screening. Since hypertension is a very prevalent condition and often asymptomatic, screening is very important. All individuals over 18 should be screened for hypertension at least once every three years until they reach 40, in which case they should be screened at least once a year. Individuals over 18 with risk factors or prehypertension should be screened at least yearly.

Diagnosis is made when BP values ≥ 140/90 mmHg (measured manually) or ≥ 135/85 mmHg (measured automatically) are obtained in healthcare visits. These values must be confirmed more than once in different visits (at least three to six visits).

If white-coat hypertension is suspected, ambulatory blood pressure monitoring (ABPM) can be used. When using ABPM, the following values are diagnostic of hypertension:

24h average BP > 135/85 mmHg.
Daytime (awake) BP > 140/90 mmHg.
Nighttime (asleep) BP > 125/75 mmHg.

If the patient cannot afford ABPM, he can measure his own BP with an automatic device at home. In this case, if measured BP values are equal or above 135/85 mmHg hypertension is confirmed.

Some individuals should be investigated for secondary hypertension. These individuals include the ones with:

Early onset of hypertension (<30) with no other risk factors.
Acute rise of BP or paroxysmal episodes in an individual with previously normal BP
Resistant hypertension (hypertension that does not improve with adequate doses of three drugs from different classes)

TREATMENT:

Every patient with BP ≥ 140/90 mmHg should be treated. In patients older than 80 it may be acceptable to tolerate higher levels of SBP and in such patients treatment should be started if SBP ≥ 150 mmHg (or DBP ≥ 90 mmHg).

The adoption of lifestyle modification is beneficial for every patient, even for those with prehypertension. Lifestyle modification includes diet sodium reduction (max of 2.4g of sodium or 6g of sodium chloride/day), physical activity (at least 30 minutes, at least 4 days/week), weight reduction, dietary modification and reduction in alcohol consumption.

As far as drug therapy goes, the main choices for initial treatment are:

Thiazide diuretics (Hydrochlorothiazide, Chlorthalidone, Metolazone, Indapamide)
ACE inhibitors (Captopril, Lisinopril, Fosinopril, Ramipril, Enalapril. Quinapril)
ARBs (Losartan, Valsartan, Olmesartan, Eprosartan, Azilsartan, Telmisartan)
Calcium channel blockers

Others classes of medications that may reduce BP but are no longer used as first line therapy (except in particular cases) include:

Beta blockers (Atenolol, Metoprolol, Labetalol Propranolol, Pindolol, Carvedilol, Acebutalol, Bisoprolol, Esmolol)
Alpha blockers (Doxazosin, Prazosin, Terazosin)
Central alpha agonists (Methyldopa, Clonidine)
Aldosterone antagonists (Spironolactone, Eplerenone)
Loop diuretics (Furosemide, Torsemide, Bumetanide, Etacrynic acid)
Potassium sparing diuretics (Triamterene, Amiloride)
Vasodilators (Hydralazine, Minoxidil, Nitroprusside, nitroglycerine)
Renin inhibitors (Aliskiren)
Others (Reserpine)

How to treat?

In general, patients should be treated with a single medication at the beginning. If the medication works (reaches the goal) at the maximum dose tolerated, it should be continued. If not, a different drug should be tried or a second drug added.

Starting with two drugs may be considered in patients with a baseline blood pressure more than 20/10 mmHg above goal.

The best choices for initial monotherapy are ACE inhibitors, ARBs, thiazide diuretics or CCBs. Black patients tend to respond better to CCBs or diuretics rather than ACE inhibitors. When using a diuretic, chlorthalidone is probably superior to HCTZ.

If combined therapy is necessary, the best initial combination therapy is an ACE inhibitor or ARB PLUS

It is important to note that lower levels of DBP (<80-85 mmHg) should be avoided since they are may be associated with cardiac events as well.

Patients with CKD (particularly the proteinuric ones with urinary protein ≥ 500mg/day) may be treated with even lower blood pressure levels than the general population, since they have good outcomes with BP levels under 130/80 mmHg

Goal blood pressure:

Recent guidelines (JNC 8) recommend a goal blood pressure of <140/<90 mmHg for all patients, including patients with DM, CKD and the general population <60 years (for patients older than 60, BO should be under 150/90 mmHg).

Other recommendations based in different studies include:

In patients without high risk for CVD or diabetes: <140/<90 mmHg (manual measuring).
If diabetic: < 125 to 130/<90 mmHg.
If stablished cardiovascular disease or very high risk: < 120 to 125/<90 mmHg

Management of Hypertensive urgency:

Patients with very high BP but no evidence of organ damage should be treated with oral medication such as captopril (12.5mg) or clonidine (0.2mg) at the beginning, and then a chronic medication should be started. The BP should be lowered slowly, over a period of hours to days. Around 25% of the BP should be lowered in the first day, with the rest being reach in the days after.

Management of Hypertensive emergency:

The treatment of hypertensive emergencies is discussed in another article and it depends on the particular manifestation. In general, it requires parenteral medications.

REFERENCES & FURTHER READING:

  1. James PA et al. 2014 Evidence-Based Guideline for the Management of High Blood Pressure in AdultsReport From the Panel Members Appointed to the Eighth Joint National Committee (JNC 8).  JAMA. 2014;311(5):507-520. doi:10.1001/jama.2013.284427.
  2. Multiple Authors. 2013 ESH/ESC Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J (2013) 34 (28): 2159-2219.
  3. Franklin SS. et al. Masked Hypertension A Phenomenon of Measurement. Hypertension. 2015;65:16-20
  4. Papadopoulos DP, Makris TK. Masked hypertension definition, impact, outcomes: a critical review. J Clin Hypertens (Greenwich). 2007 Dec;9(12):956-63.
  5. Qaseem A et al. Pharmacologic Treatment of Hypertension in Adults Aged 60 Years or Older to Higher Versus Lower Blood Pressure Targets: A Clinical Practice Guideline From the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med. [Epub ahead of print 17 January 2017] doi: 10.7326/M16-1785.