Recommended reading: The Hypertension Paradox

Hypertension is the increase in systolic pressure, diastolic pressure or both. The threshold at which a person is called hypertensive used to be 140/90mm Hg but there is a suggestion now that 130/80 mm Hg should be the threshold value. However, treatment with anti-hypertensive medication is still recommended only when the BP is persistently 140/90mm Hg or above unless there is a compelling indication to do so at a lower level.

In 1998, data from the Hypertension Optimal Treatment (HOT) trial informed us that for people above 50 years of age, it is adequate to keep the diastolic BP below 90 mm Hg.

In 2009, a meta-analysis of data from 7 trials informed us that treating patients with hypertension to a goal of 135/85mm Hg to 140/90mm Hg was adequate (Reference).

In 2010, the Action to Control Cardiovascular risk in Diabetes (ACCORD) study informed us that for people with Type 2 diabetes, a systolic BP goal of less than 140 mm Hg was adequate to protect against cardiac complications while a systolic BP goal of less than 120mm Hg was better in protecting against stroke.

In 2015, the SPRINT (Systolic Blood Pressure Intervention) trial informed us that for people above 50 years of age who have increased CV risk but not diabetes or stroke, it is better to keep the systolic BP below 120mm Hg even though they may have more adverse effects as a result of treatment.

in 2016, the HOPE-3 (Heart Outcomes Prevention Evaluation) trial informed us that for men above 55 years and women above 65 years who do not have chronic kidney disease or atherosclerotic vascular disease, keeping the systolic blood pressure below 135 mm Hg is good enough.

In 2017, the value of 130/80mm Hg was recommended by the ACC-AHA as the threshold for diagnosis of hypertension. This new recommendation is based largely on the SPRINT trial. Accordingly,

  • Normal BP is less than 120mm Hg systolic and less than 80mm Hg diastolic
  • Elevated BP is 120 – 129mm Hg systolic with a diastolic BP of less than 80mm Hg
  • Stage 1 hypertension is when systolic BP is 130 – 139 mmHg or diastolic BP of 80 – 89 mm Hg
  • Stage 2 hypertension is when systolic BP is 140mm Hg and above or diastolic BP is 90mm Hg and above.

Question: Why is 130mm Hg (systolic) taken as the treatment target in the new guidelines?
Answer: Because the SPRINT trial showed a benefit in preventing myocardial infarction, acute coronary syndromes, strokes, acute heart failure and death from CV causes when systolic blood pressures are below this level in people above 50 years who have increased CV risk [one person avoids one of these events when 61 patients are treated for 3 years].
Increased cardiovascular risk means: clinical or subclinical coronary artery disease, chronic kidney disease (not due to polycystic kidney disease) with eGFR less than 60ml/min (calculated by MDRD formula), age more than 75 years and those with a calculated 10-year coronary risk score of more than 15 percent (calculated by the Framingham risk score method).

Question: Is there any risk in reducing the systolic BP to below 120mm Hg with treatment?
Answer: Yes, hypotension and syncope as well as acute kidney injury and electrolyte abnormalities can occur [one person will develop one of these adverse events when 45 people above the age of 50 years are treated].

Question: If a patient comes to you with a blood pressure of 140/90 mm of Hg, and asks you if he has hypertension, what will you answer?
Answer: The BP is high enough for a diagnosis of hypertension. Whether treatment with medicines is immediately necessary depends on whether the patient has a 10 year CV risk of more than 10% based on Framingham risk score. For those at low risk, pharmacological treatment may not be needed yet but they will need attention to salt intake, weight and exercise. Treatment with medicines may be needed at a later stage.

Question: A 52 year old man asks you: Which is more important - systolic BP or diastolic BP? What will you answer?
Answer: Both systolic BP and diastolic BP are important in adults. Systolic BP becomes increasingly important with older adults. Control of both is needed to reduce cardiovascular risk (Ref. Cardiovascular Health Study). In those below the age of 40 years and in certain populations like black Americans, an increase in diastolic pressure an increase in diastolic BP is associated with increased CV risk. The pulse pressure (difference between systolic and diastolic) can become wider with increasing age because of reduced arterial compliance. In those with an increased pulse pressure due to age (that is, increased vascular stiffness), attempts to reduce the systolic BP to below 140mm Hg may result in frequent adverse events like syncope, poor cognition and acute kidney injury.

Question: You diagnose a patient with "essential hypertension" and prescribe medication. The patient asks: If the hypertension is "essential" why should I take medicines? What will you answer?
Answer: The term essential used to mean "necessary" in the past but that meaning is incorrect. The term essential hypertension simply means that the hypertension is without any obvious cause.

Question: What will make you say: This blood pressure cuff is unsuitable for measuring blood pressure for this person?
Answer: An unsuitable blood pressure cuff is one that does not cover at least 80 percent of the arm circumference.

Question: How long should a person sit down before the blood pressure is measured? Should coffee and smoking be avoided before checking blood pressure?
Answer: The new hypertensive guidelines from ACC/AHA in 2017 recommend that BP should be measured only after 5 minutes of restful sitting with the arm supported at the heart level and with the legs uncrossed and feet resting on the floor. The average of 3 readings should be taken as the measured BP. Yes, coffee and smoking should be avoided for 30 minutes prior to measuring BP.

Question: In a person who has never measured his blood pressure before, and is now newly noted to have high BP, how will you know whether the blood pressure was long standing or not?
Answer: By looking for evidence of target organ damage in the eyes (retinopathy) and heart (hypertrophy).

Question: When will you suspect that a person has secondary hypertension and not essential hypertension?
Answer: Secondary hypertension should be suspected when high BP is first detected at extremes of age (in the very young or the elderly), when the blood pressure is alarmingly high at first presentation and when the BP is difficult to control with usual medication.

Question: What is the target blood pressure when treating hypertension?
Answer: The usual target is to keep the BP below 140/90mm Hg but the new hypertension guidelines recommend treating to a systolic target below 130 mm Hg for those at high CV risk.

Question: What is the first choice of anti hypertensive drugs?
Answer: The initial choice of anti-hypertensive treatment should be from one of the four classes of antihypertensive agents known to reduce CV risk: ACEI, ARB, Calcium Channel Blockers and Thiazide-type diuretics (chlorthalidone, hydrochlorothiazide, indapamide).

The various classes of anti-hypertensive drugs are: Thiazide diuretics (eg hydrochlorothiazide), Loop diuretics (eg frusemide), Potassium sparing diuretics (eg spironolactone and triamterene), Beta blockers (eg metoprolol), ACE inhibitors (eg perindopril), Angiotensin Receptor Blockers (eg losartan), Alpha adrenergic blockers (eg prazocin), Non dihydropyridine calcium channel blockers (eg diltiazem), Dihydropyridine calcium channel blockers (eg amlodipine), Directly acting vasodilators (eg hydralazine), Centrally acting adrenergic inhibitors (eg methyldopa).

The first choice of anti hypertensive drugs may depend on the presence of existing conditions.

Condition Anti hypertensive drug
Chronic kidney disease ACEI or ARB
Congestive heart failure Beta blocker or diuretic
Ischemic heart disease Beta blocker
Migraine Beta blocker
Benign prostate enlargement Alpha blocker
Essential tremor Beta blocker

Question: Which antihypertensive drug must you try to avoid in patients who……….
a. Are pregnant? Answer: ACE inhibitors and Angiotensin receptor blockers
b. Have asthma or COPD? Answer: Beta blockers
c. Have peripheral vascular disease? Answer: Beta blockers
d. Have gout? Answer: Thiazide diuretics
e. Have first or second degree heart block? Answer: Beta blockers and non-dihydropyridine calcium channel blockers

Question: What side effect should you be concerned about when using the following intravenous antihypertensive drugs?
a. Nitroprusside? Answer: Methaemoglobinemia, thiocyanate and cyanide toxicity (occurs with prolonged administration only)
b. Nitroglycerin? Answer: Headache
c. Labetolol? Answer: Bradycardia

Question: When using an intravenous antihypertensive medication, what is your target BP for a hypertensive urgency situation…
a. in the first two hours? Answer: To lower the mean arterial pressure by about 25% only
b. from 2 to 24 hours? Answer: To lower the BP to about 160/100 mm Hg within this period.

Question: In which group of patients is it better to titrate the doses of antihypertensive drugs to the standing BP?
Answer: In patients who are elderly, who have long standing diabetes and those who, for any reason, are prone to have autonomic neuropathy.

Tidbits of information
The white coat effect should be considered as a possible contributing factor during office measurements of BP whenever the blood pressure is high. Masked hypertension – when BP at home is higher than in the office – should be suspected when the severity of target organ damage is out of proportion to the BP recordings in the office.

Lifestyle changes for hypertension generally refer to: less than 1500mg of sodium per day in the diet; 90 to 150 minutes of aerobic or resistance exercises per week, less than 2 alcoholic drinks per day for men and 1 alcoholic drink per day for women, weight loss if indicated, stop smoking and increase intake of potassium-rich food. Diet alone can reduce systolic BP by as much as 11mm Hg and diastolic BP by 5mm Hg – as seen in those who use the DASH diet

While 80% of people who need a single daily dose will be compliant to their treatment, only 50% of those who need 4 daily doses will be compliant.

It is not sure if strict control of BP according to new guidelines will prevent progression of CKD in those with diabetes and in those without proteinuria.

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