Hypertension

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Hypertension is a multisystem disease whose hallmark is the elevation of blood pressure.

Classification

Classification of blood pressure for adults
Blood pressure classification Initial blood pressure mm Hg Followup recommended
SBP DBP
Normal <120 and <80 Recheck in 2 years
Prehypertension 120-139 or 80-99 Recheck in 1 year
Stage 1 Hypertension 140-159 or 90-99 Confirm within 2 months
Stage 2 Hypertension >160 or >100 "Evaluate or refer to source of care within 1 month. For those with higher pressures (e.g., >180/110 mmHg), evaluate and treat immediately or within 1 week depending on clinical situation and complications."

Diagnosis

A systematic review by the Rational Clinical Examination has reviewed the research on measuring the blood pressure.[1]

If the diastolic pressure is below 110 mm Hg, it should be confirmed on two addition visits as some patients will have a lower blood pressure on repeat measurements.[2] A larger cuff should be used for obese patients.[3]

21% of patients with untreated borderline hypertension (diastolic pressure between 90 and 104 mm Hg) may have normal blood pressures outside of the doctor's office.[4]

Some patients may have their blood pressure rise by as much as 25 mm Hg due to an alarm reaction upon seeing a doctor.[5]

Elderly patients may have pseudohypertension due to inability of the blood pressure cuff to compress stiff arteries.[6] Pseudohypertension may be detected by Osler's maneuver.[6]

Excluding secondary hypertension

Listening for an abdominal bruit, especially if it is both systolic and diastolic, may help detect underlying renal artery stenosis.[7]

Among patients with resistant hypertension (blood pressure >140/90 mm Hg despite a three drug regimen, 20% of patients had serum aldosterone and plasma renin activity ratio of more than 65:16 with a aldosterone concentration above 416 pmol/L. However, only 10% of all patients had primary aldosteronism. Half of these patients have a normal serum potassium.[8]

Treatment

Current clinical practice guidelines are based on The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7)[9] and the 2007 guidelines by the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC).[10] Drugs for hypertension, called antihypertensives as a group, have been reviewed by the Medical Letter.[11]

Treatment goals

Per the JNC7 Guidelines:[9]

  • "Treating "most patients" SBP and DBP to targets that are <140/90 mmHg is associated with a decrease in cardiovascular complications.
  • In patients with hypertension and diabetes or renal disease, the BP goal is <130/80 mmHg.

Non-drug treatment

Initial medication

Clinical practice guidelines have tried to make blanket recommendations for all patients:

  • "Thiazide-type diuretics for most" patients are recommended by the JNC7 clinical practice guidelines.[9]
  • "[[|Adrenergic beta-antagonist|ß-blockers]], especially in combination with a thiazide diuretic, should not be used in patients with the metabolic syndrome or at high risk of incident diabetes" is noted by the European ESH/ESC clinical practice guidelines.[10] The ESH/ESC guidelines cite the LIFE[12] and ASCOT[13] trials. Unlike the ALL HAT study[14], both of these trials were in largely anglo populations, supported by industry, and at the same institution. All patients in the LIFE trial had left ventricular hypertension (LVH). Based on these two trials, a meta-analysis has concluded that beta blockers should not be the first choice treatment.[15]
Efficacy of different drugs. From Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.[16]

However, the Veterans Affairs Cooperative trial suggests the initial drug may be better selected based on the patient's age, race, and gender.[16][17] The patient's demographic roughly corresponds with their renin profile, but is more predictive than the renin profile.[17] The molecular basis is being determined.[18]

In the Veterans Affairs Cooperative, among the the high renin demographic (young whites), diuretics had similar efficacy to placebo; whereas in the low renin demographic (older blacks), the ace-inhibitors had similar efficacy to placebo in the Veterans Affairs Cooperative Study Group on Antihypertensive Agents (see figure).[16] Similarly, a meta-analysis has concluded that beta-blockers are a good first choice for younger patients, but not for older patients.[19]

Predicting response to anti-hypertensives based on demographics
Category name demographics Comments Best anti-hypertensive categories
High renin demographic less than 50 years old, anglo salt-sensitive; diuretic responsive diuretics, calcium channel blockers
Low renin demographic more than 50 years old, non-anglo* ace-inhibitors, ß-blockers
* Obesity and female[20] are also associated with low renin.

Several randomized controlled trials have compared initial medications for hypertension.[21][22][23][16]

  • In the Second Australian National Blood Pressure study (ANBP2),[22][[Angiotensin-converting enzyme inhibitor|ace-inhibitors] were better in a population that was 95% white with a body-mass index of 27. This demographic has features of both high (age) and low (race) renin status.
  • In the ALLHAT study,[21] diuretics were better in a population that was 47% white with a body-mass index of 30.

For patients with Stage 2 Hypertension (SBP >160 or DBP>100 mmHg), start with two drugs.[9]

The race and age demographic may partly predict frequency of drug toxicity to different anti-hypertensive medications.[24]

Resistant hypertension

Blood pressure may be difficult to treat, especially in older patients.[25][26] Clinical practice guidelines from the American Heart Association (AHA) address the management of resistant hypertension.[27]

Physiology

Resistant hypertension is characterized by volume expansion and abnormalities of the renin-angiotensin system with high aldosterone and cortisol with low renin levels in the plasma in spite of 85% of patients in the study taking thiazide diuretics.[28] This suggests that high corticotropin may contribute[28], in some cases due to an abnormal cytochrome P-450 3A5 allele that may reduce metabolism of cortisol and corticosterone (a precursor of aldosterone).[29] Resistent hypertension is also associated with insulin resistance.[30]

Evaluation

The AHA defines resistant hypertension as "blood pressure that remains above goal in spite of the concurrent use of 3 antihypertensive agents of different classes."

First, 'pseudoresistance' should be considered:[27]

  • Medication noncompliance
  • Inadequate prescribing by the health care provider[31] may be the most common cause of persistent hypertension.[32][33]
  • White coat hypertension, pseudohypertension and other problems of measurement.[34]

Next, secondary hypertension should be considered:[27]

Treatment

The AHA recommends that one of the three medicines use for hypertension should be a diuretic.[27]

In an unblinded, uncontrolled extension of the ASCOT randomized controlled trial, spironolactone 25-50 mg per day as a fourth medication reduced the blood pressure by 21.9/9.5. This result was not affected by whether one of the first three medications included a diuretic.[37]

Systolic hypertension

For more information, see: Systolic hypertension.


Elderly patients

Treating patients aged 80 years or older for two years who have a systolic pressure over 160 mm hg (the average entry pressure was 173/91 mm Hg) and treating to 150/80 mm Hg may reduce morbidity.[38] In this trial, the average seated blood pressure at the end of the study in the treatment group was 143/78.

Prognosis

References

  1. Reeves RA (1995). "The rational clinical examination. Does this patient have hypertension? How to measure blood pressure". JAMA 273 (15): 1211–8. PMID 7707630[e]
  2. Hartley RM, Velez R, Morris RW, D'Souza MF, Heller RF (1983). "Confirming the diagnosis of mild hypertension". Br Med J (Clin Res Ed) 286 (6361): 287–9. PMID 6402075[e] PubMed Central
  3. Nielsen PE, Larsen B, Holstein P, Poulsen HL (1983). "Accuracy of auscultatory blood pressure measurements in hypertensive and obese subjects". Hypertension 5 (1): 122–7. PMID 6848459[e]
  4. Pickering TG, James GD, Boddie C, Harshfield GA, Blank S, Laragh JH (1988). "How common is white coat hypertension?". JAMA 259 (2): 225–8. PMID 3336140[e]
  5. Mancia G, Parati G, Pomidossi G, Grassi G, Casadei R, Zanchetti A (1987). "Alerting reaction and rise in blood pressure during measurement by physician and nurse". Hypertension 9 (2): 209–15. PMID 3818018[e]
  6. 6.0 6.1 Messerli FH, Ventura HO, Amodeo C (1985). "Osler's maneuver and pseudohypertension". N. Engl. J. Med. 312 (24): 1548–51. PMID 4000185[e]
  7. Turnbull JM (1995). "The rational clinical examination. Is listening for abdominal bruits useful in the evaluation of hypertension?". JAMA 274 (16): 1299–301. PMID 7563536[e]
  8. Lancet 2008; 371:1921-1926 Template:DOI
  9. 9.0 9.1 9.2 9.3 Chobanian AV, Bakris GL, Black HR, et al (2003). "The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report". JAMA 289 (19): 2560-72. DOI:10.1001/jama.289.19.2560. PMID 12748199. Research Blogging. http://www.nhlbi.nih.gov/guidelines/hypertension/jnc7full.pdf
  10. 10.0 10.1 Mancia G, De Backer G, Dominiczak A, et al (June 2007). "2007 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. 28 (12): 1462–536. DOI:10.1093/eurheartj/ehm236. PMID 17562668. Research Blogging.
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  15. Lindholm LH, Carlberg B, Samuelsson O (2005). "Should beta blockers remain first choice in the treatment of primary hypertension? A meta-analysis". Lancet 366 (9496): 1545–53. DOI:10.1016/S0140-6736(05)67573-3. PMID 16257341. Research Blogging. ACP Journal Club review
  16. 16.0 16.1 16.2 16.3 Materson BJ, Reda DJ (1994). "Correction: single-drug therapy for hypertension in men". N. Engl. J. Med. 330 (23): 1689. PMID 8177286[e] Cite error: Invalid <ref> tag; name "pmid8177286" defined multiple times with different content
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See also