15 - Hypertension Flashcards
What is the trend of age related to HTN?
- Males more likely than females from 35-64
- From 65 and older females become more likely
What determines BP?
Cardiac output * peripheral resistance
Why do we want to lower BP?
For long-term prevention of heart attacks, strokes, kidney failure, eye damage, etc.
HTN is a significant risk factor for…?
- Cerebrovascular disease
- Coronary artery disease
- Congestive heart failure
- Renal failure
- Peripheral vascular disease
- Dementia
- Atrial fib
- Erectile dysfunction
Goals of therapy for adults w/ HTN
- Systolic BP less than 140 mmHg
- Diastolic BP less than 90 mmHg
- Mortality greatly increases if systolic BP > 160 mmHg and/or if diastolic > 90-100 mmHg
Benefit of HTN tx
- *Benefit is related to risk
- Those w/ lower CV risk will have less benefit than those w/ greater CV risk
Describe the sprint study
- Studied px at high risk of CVD (average 10-year CVD risk = 20%), no DM2 (px w/ LVEF < 35% or stroke also excluded)
- Not blinded
- Studied intensive (SBP < 120) vs. standard (SBP < 140) BP control; any standard anti-hypertensive could be used; follow-up after 3.3 years
- Took 2 anti-HTN meds to get px to an average of 135/76
- Took 3 anti-HTN meds to get px to an average of 121/69 (couldn’t get them to an average of 120 SBP)
Describe the results of the sprint study
- ARR (absolute risk reduction) using intensive for primary outcome (ex: MI, ACS, stroke, HF, CV death) was 1.6%; NNT = 62
- ARI (absolute risk increase) using intensive for renal (AKI or ARF) was 1.8%; NNH = 56
- ARI using intensive for >/ 30% decrease in eGFR to < 60 mL/min was 2.7%; NNH = 37
- ARI using intensive for serious adverse effects (life-threatening, permanent disability, hospitalization) was 2.2%; NNH = 46
What are the current Canadian recommendations for HTN tx?
- For high-risk px aged >/ 50 years w/ SBP >/ 130 mmHg, intensive management to target a SBP < 120 mmHg should be considered
- Px selection for intensive management is recommended & caution should be taken in certain high-risk groups
- High-risk adults as candidates for intensive management:
- Clinical or subclinical CVD or
- Chronic kidney disease or
- Estimated 10-year global CV risk >/ 15% or
- Age >/ 75 years
- Px w/ >/ 1 clinical indication should consent to intensive management
Most important drug causes of HTN
- NSAIDs
- Decongestants
- Alcohol
- Estrogen
- Also some herbal supplements (when mixed w/ Rx)
What are some options for non-drug therapy for HTN?
- Allow 3-6 months of lifestyle modification before considering medication (in most cases)
- Examples – exercise (150 min/week of mild-moderate); diet (caffeine intake, fat intake); 1-2 cups of coffee per day isn’t a big deal; stress management; weight reduction
- DASH diet (fruits, vegetables, low-fat dairy, dietary fiber, grains, etc.)
- Reduce sodium intake toward 2000 mg (5 g of salt or 87 mmol Na) per day
MOA of CCBs
Decrease contractility and vasoconstriction
MOA of thiazide diuretics
Decrease sodium/water reabsorption => decrease TPR
Describe the ALLHAT study
- Studied over 33,000 patients w/ HTN & at least 1 other risk factor for CHD events
- Followed them for 5 years on chlorthalidone 12.5-25 mg (thiazide), lisinopril 10-40 mg (ACE inhibitor), or amlodipine 2.5-10 mg (DHP CCB)
- Results = BP reduction chlorthalidone > amlodipine > lisinopril; however, no difference between 3 agents in fatal coronary heart disease or non-fatal MI or mortality
- *Similar efficacy overall
Adverse reactions w/ thiazide diuretics
- Electrolyte imbalances
- Increased uric acid
- Decreased glucose
Adverse reactions w/ ACE inhibitors
- Dry cough
- Increased potassium
Adverse reactions w/ ARBs
Increased potassium and sCr
Adverse reactions w/ beta-blockers
- Cold extremities
- Fatigue
- Nausea
- Decreased exercise tolerance
Adverse reactions w/ DHP CCBs
- Flushing
- Ankle edema
- Headache
- Increased HR
Are beta-blockers useful for lone HTN?
- Better reduction of CV events vs. placebo in < 60 y/o; no benefit in > 60 y/o
- Vs. other anti-HTN agents – beta-blockers have similar reduction of CV events in < 60 y/o, but worse in > 60 y/o (small increase in strokes)
Should beta-blockers ever be used first line for HTN?
Yes, if CHF or angina, or as an option for A Fib
What are some special considerations for anti-HTN agents?
- Thiazides are less effective if Clcr < 30 mL/min
- ACE inhibitors, ARBs, & beta blockers may be less effective in black patients
- CCBs have CYP 3A4 interactions
What are some generalizations about choosing an anti-HTN agent?
- Efficacy, convenience, & cost are all similar
- Safety/adverse effects is what varies & what determines the agent based on pt
Which agent should be chosen for initial thiazide therapy?
- HCTZ considered (at best) equal to and very likely inferior to chlorthalidone
- Therefore, consider chlorthalidone or indapamide when initiating thiazide diuretic therapy for HTN
What is the recommendation for HTN in type 2 diabetes?
- Meta-analyses of over 73,000 px concluded that if SBP < 140 mmHg, further tx associated w/ increased risk of CV death, w/ no observed benefit
- Didn’t persuade CHEP or CDA to change guidelines that state BP target is 130/80
Which anti-HTN agent is best for type 2 diabetes?
- CHEP 2018 recommendation = ACE inhibitor, ARB, DHP CCB, or thiazide/thiazide-like diuretic (no preference)
- Dipiro = ACE inhibitor or ARB
Describe the ALLHAT study of diabetes subgroup
- Looked at over 13,000 px taking chlorthalidone, lisinopril, & amlodipine
- No difference in incidence of end-stage renal disease between chlorthalidone & lisinopril
- No difference in coronary heart disease, stroke, or combined CV disease between the 3
Describe the role of ACE inhibitors/ARBs in renal protection for type 2 diabetes
- When compared to placebo or other anti-HTN in px w/o albuminuria (no kidney disease):
- ACEi are only agents shown to reduce incidence of microalbuminuria in diabetics
- No significant decrease in incidence of double of sCr or ESRD
- Vs. placebo or other anti-HTN in px w/ albuminuria -> reduced progression of nephropathy -> ESRD
Describe the general rules for HTN in type 2 diabetes
- Best evidence for target of DBP < 85-90 mmHg and SBP < 140 mmHg
- Long-term CV protection is similar for first-line agents
- For those w/o diabetic kidney disease, ACEi & ARB reduce likelihood of developing microalbuminuria but not doubling of sCr or ESRD
- For those w/ diabetic kidney disease, ACEi & ARB both delay progression of nephropathy to ESRD
Describe the research done regarding combination therapy for HTN?
- Summary of 354 HTN trials => using half-standard doses results in 20% less BP reduction
- 119 trials compared mono vs. combo therapy => greater incidence of adverse effects w/ combo (5.2% w/ mono vs. 7.5% w/ combo)
What is the general consensus of combination therapy in HTN?
- Use of 2 drugs initially generally not a rational approach
- Smaller doses often do almost as good of a job at BP reduction as larger doses
- Adding an agent is additive for BP reduction, but less than additive for adverse effects
What is the importance of treating HTN in elderly?
- Elderly more sensitive to symp inhibition & volume depletion => increased orthostatic hypotension => increased risk of falls & morbidity
- Low BP may be associated w/ dementia, cancer, HF, & MI
- Age > 85 y/o w/ low SBP (< 120) associated w/ increased mortality
- Age ~ 70 y/o w/ low DBP (< 65) associated w/ increased stroke & CV event risk
- Isolated systolic HTN & wide pulse pressures increase risk of MI, stroke, & renal failure
What was the HYVET study researching?
HTN in the very elderly
Describe the HYVET study
- Over 3,000 px aged 80 y/o and older; SBP >/ 160 mmHg (baseline 173/91)
- Target BP was 150/80
- Active-tx group = indapamide 1.5 mg OD + perindopril 2-4 mg OD added if necessary, vs. placebo
- Placebo decreased BP to 159/84; active decreased to 144/78 (20% of placebo reached target; 48% of active reached target)
- Reduction to < 150/80 decreased CV events by 3% over 3 years and decreases mortality by 2.2% -> is this worth it to the pt? probably not
What is the general approach to treating HTN in the elderly?
- BP reduction in very elderly w/ HTN is beneficial
- Target = < 150/80 (likely not applicable to frail elderly)
- Outcome benefits apparent w/in first year
- Agent doesn’t matter; thiazide or ACEi reasonable first line options
- 50% will reach target BP w/ 2 agents, but only start w/ 1 (think about tx burden)
