What are the guidelines for managing hypertension in British Columbia?

British Columbia Hypertension Management Guidelines

The British Columbia hypertension guidelines recommend initiating antihypertensive drug treatment in all patients with sustained systolic blood pressure ≥160 mmHg or sustained diastolic blood pressure ≥100 mmHg, while using non-pharmacological measures for all hypertensive and borderline hypertensive individuals. 1

Blood Pressure Measurement

Proper measurement technique is essential for accurate diagnosis and management:

• Use a validated, properly maintained and calibrated device
• Position patient seated with arm at heart level
• Use appropriate cuff size adjusted for arm circumference
• Deflate cuff at 2 mm/s and measure BP to nearest 2 mmHg
• Record diastolic pressure at disappearance of sounds (phase V)
• Take at least two measurements at each visit over several visits 1

Ambulatory Blood Pressure Monitoring (ABPM) Indications

• Unusual BP variability
• Resistant hypertension (≥3 drugs)
• Suspected hypotension
• Suspected white coat hypertension 1

Thresholds for Intervention

1. Immediate drug treatment required:

   • Sustained SBP ≥160 mmHg or DBP ≥100 mmHg despite non-pharmacological measures
   • Malignant/accelerated hypertension
   • Severely elevated BP (>220/120 mmHg)
   • Impending complications (TIA, left ventricular failure) 1

2. Drug treatment indicated for sustained SBP 140-159 mmHg or DBP 90-99 mmHg if:

   • Target organ damage present
   • Established cardiovascular disease
   • Diabetes
   • 10-year cardiovascular disease risk ≥20% 1

Treatment Targets

• Standard target: ≤140 mmHg systolic and ≤85 mmHg diastolic
• Higher risk patients (diabetes, renal impairment, established cardiovascular disease): ≤130/80 mmHg
• Minimum acceptable control (audit standard): <150/90 mmHg 1
• When using ambulatory readings, targets are approximately 10/5 mmHg lower than office equivalents 1

Non-Pharmacological Management

All hypertensive and borderline hypertensive patients should receive lifestyle modification advice:

1. Weight management: Reduce energy intake to achieve ideal body weight 1
2. Physical activity: Regular dynamic exercise (e.g., brisk walking) rather than isometric exercise 1
3. Alcohol limitation: <21 units/week for men, <14 units/week for women, with alcohol-free days each week 1
4. Dietary sodium reduction: Eliminate table salt, reduce salty foods 1
5. Increased fruit and vegetable consumption 1
6. Smoking cessation 1
7. Dietary fat modification: Reduce saturated fats, increase polyunsaturated/monounsaturated fats 1
8. Increased oily fish consumption 1

These lifestyle modifications can reduce the need for drug treatment or decrease the number/dose of medications required 1.

Pharmacological Treatment

First-line agents (in absence of compelling indications for other drugs):

• Low-dose thiazide or thiazide-like diuretics (e.g., hydrochlorothiazide, chlorthalidone)
• Beta-blockers 1, 2

Other first-line options include:

• Angiotensin-converting enzyme (ACE) inhibitors
• Angiotensin receptor blockers (ARBs)
• Calcium channel blockers 2

Evaluation of Hypertensive Patients

Routine Investigations

• Urine strip test for blood and protein
• Blood electrolytes and creatinine
• Blood glucose
• Serum total:HDL cholesterol ratio
• 12-lead ECG 1

Indications for Specialist Referral

• Urgent treatment needed (malignant hypertension, impending complications)
• Suspected secondary causes of hypertension
• Treatment failures or problems
• Special circumstances (variable BP, white coat hypertension, pregnancy) 1

Implementation Considerations

Effective implementation of lifestyle modifications requires:

• Knowledge and enthusiasm from healthcare providers
• Patience and time spent with patients and families
• Clear written information
• Ideally delivered by well-trained health professionals (e.g., practice or clinic nurses) 1

Common Pitfalls to Avoid

1. Inadequate BP measurement: Ensure proper technique and multiple readings
2. Overlooking white coat hypertension: Consider ABPM when suspected
3. Neglecting orthostatic changes: Measure standing BP in elderly and diabetic patients 1
4. Insufficient lifestyle counseling: Provide comprehensive advice and follow-up
5. Ignoring overall cardiovascular risk: Consider 10-year CVD risk in treatment decisions 1
6. Suboptimal BP targets: Aim for recommended targets based on patient risk profile 1

The BC hypertension guidelines emphasize a comprehensive approach that includes proper diagnosis, risk stratification, lifestyle modifications, and appropriate pharmacological therapy tailored to the individual's risk profile.