Tuesday, December 2, 2014

Hypertension


Since we often discuss inpatient issues during morning report and noon rounds, let's focus on an outpatient issue instead. Hypertension (HTN) is extremely common (20% of Canadians over the age of 18) and is a signifcant risk factor for end-organ dysfunction. The inpatient management of hypertension is very different from the outpatient management of hypertension. The information below is from the CHEP Guidelines, a Canadian hypertension guideline.

Diagnosis
High blood pressure is defined by a BP >140/90. The flow chart for the diagnosis of HTN can be complication, but basically the diagnosis is often made over the course of 3 ambulatory clinic visits. HTN is defined by a BP greater than 140/90.

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The next step is to use either clinic BP monitoring (BPM), ambulatory monitoring (ABPM), or home monitoring. If using clinic BPM, a BP greater than 140/90 in three subsequent visits clinches the diagnosis, or a BP greater than 160/100 in any of those three diagnosis. For ABPM and Home BPM, a consistent BP of  greater than 135/85  makes the diagnosis.

Beware of two entities:
1. White Coat HTN: BP greater than 140 in the clinic but less than 135 via ABPM (should not treat as HTN).
2. Masked HTN: BP greater than 135 on APM but less than 140 in the clinic (should treat as HTN).

Investigations
Should be done for all patients with newly diagnosed HTN.
1. Urinalysis
2 .Blood chemistry (potassium, sodium and creatinine)
3. Fasting glucose and/or glycated hemoglobin (A1c)
4. Fasting total cholesterol and high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), triglycerides.
5. Standard 12-leads ECG
                                                   
Treatment
1) Non-Pharmacological
o    Physical Exercise – Should be recommended 30-60 minutes of moderate intensity exercise (walking, jogging, cycling, or swimming) x4-7/week
o    Weight loss - BMI should be 18.5 to 24.9 kg/m²
o    Alcohol Consumption -  less than 2 drinks per dayno more than 14 drinks/week for men and 9/week for women
o    Salt Intake – Restrict to 2,000 mg (5g of salt or 87mmol of sodium) per day
o    Stress - Keep it down! Don't make me come over there.

2) Pharmacological
The first step is to remove agents that can induce/aggravate HTN (NSAIDs, steroids, OCP, EPO, MAOIs, SSRIs). Next, decide on a target for BP, which are listed below:

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Next, select an anti-HTN agent. Important considerations for choosing HTN treatment:
  • Use caution when initiating therapy with 2 drugs in whom adverse events are more likely (e.g. frail elderly, those with postural hypotension or who are dehydrated).
  • If a diuretic is not used as first or second line therapy, triple therapy should include a diuretic, when not contraindicated. 
  • ACE inhibitors, renin inhibitors, and ARBs are contraindicated in pregnancy
  • Don’t use an ACE inhibitor and an ARB together, except only in people with advanced heart failure or proteinuric nephropathy. This combination does not reduce cardiovascular events more than the ACEI alone and have more adverse effects.
  • Two drug combinations of beta blockers, ACE inhibitors, and angiotensin receptor blockers have not been proven to have additive hypotensive effects. Therefore, use if together only if non-blood pressure lowering indication.
  • ACE-inhibitors are not recommended (as monotherapy) for black patients without another compelling indication.

Here is the treatment algorithm for systolic/diasltolic HTN. Note that the algorithm is similar for Isolated Systolic HTN, except beta blockers and ACE inhibitors are not considered first line.

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Phewf. That was a lot of stuff.
Why a picture of Wonder Woman at the top? Turns out, the same person who created Wonder Woman also invented the polygraph test. Hence the 'lasso of truth.' Doesn't have much to do with hypertension, except that liars have higher blood pressure....probably.

An excellent resource is  https://www.hypertension.ca/en/chep. There, you can find all the guidelines for HTN diagnosis and treatment.