26 and 27 - Anti-hypertensive Therapy Flashcards
Define systemic arterial hypertension
A chronic elevation in arterial pressure above an arbitrarily defined normal value of 140/90 mmHg***
What is a hypertensive urgency?
- SBP ≥180mmHg OR a DBP ≥120mmHg)
- NO associated acute end organ damage of CNS, cardiovascular system, or kidneys.
- BP must be reduced over hours to days, which may occur in a closely monitored outpatient setting.
What is a hypertensive emergency?
- markedly elevated BPs
-
presence of acute end organ damage, often the result of the acute rise in BP
requires immediate therapy to reduce BP within minutes to hours to prevent further morbidity and mortality
What is a hypertensive crisis?
- The termhypertensive crisisencompasses both hypertensive urgencies and emergencies and is more reflective of the high degree of BP elevation.
What is resistant hypertension?
Blood pressure that is uncontrolled despite the use of three or more antihypertensive drugs, ideally taken at optimal doses, and of which one is a diuretic.
18% overall prevalence – increased over time.
What is the most common subset of patients with resistant hypertension?
Secondary causes are more common in the subset of patients with RHTN than in the general hypertensive population
What is pseudo-resistant hypertension?
Pseudo-resistant Hypertension: Uncontrolled blood pressure that can be attributed to the “white coat” effect, poor adherence to medications, or incorrect blood pressure measurement techniques.
What are the risk factors of resistant hypertension?
- Older age, obesity
- Chronic kidney disease (CKD)
- Diabetes
- Obstructive sleep apnea (OSA)
- Consumption of a high-salt diet
- African-American race
- Female gender
What is primary hypertension?
- 90% of cases
- Idiopathic
- A genetic basis for incidence most often found in middle-aged adults
What is secondary hypertension?
10% of cases with a primary disease causing a secondary symptom of hypertension
Common cause
- Renal Parenchymal Disease
- Obstructive sleep apnea
- Renal artery stenosis
- Primary aldosteronism
Uncommon cause
- Pheochromocytoma
- Cushing syndrome
- Hyperparathyroidism
- Coarctation of the aorta
What is evidence-based treatment? (Principle #1 in HTN treatment)
- Treat with the intent of reducing risk of CV events and thereby reducing CV morbidity and mortality.
- Comparative outcomes-based clinical trialsand clinical trials in patients with concomitant cardiovascular disease (CVD) have enhanced the ability of clinicians to implement evidence-based drug therapy to manage hypertension.
What are the JNC8 blood pressure goals? (Principle #2 in HTN treatment)
60 y.o. (
What is step-care therapy? (Principle #3 in HTN treatment)
The hypertension treatment algorithm
- An important principle of management for hypertensive patients is the idea that drug therapy has to be combined with other changes in life style that help alleviate the process
- Step-care therapy has been the standard approach, and is recently revised
- This algorithm should not be used to counter the treating physician’s clinical judgement
Outline the step care therapy outlined by the AHA (this is NOT the JNC8 algorithm)
- If you have stage I hypertension (140-50/90-99) then try lifestyle modification and consider adding a thiazide. Recheck in three months.
- If you have a stage II hypertension (160+/100+) suggest lifestyle modification AND begin with two drugs - a thiazide and an ACEi, ARB or CCb OR a ACEi and a CCB. Check again in 2-4 weeks.
- When either type of patient is rechecked, determine whether patient is at the goal.
- If patient is not at the goal, either start BP meds, increase current meds or add a new one from a different class. Check again in 2-4 weeks.
- If when you recheck, the patient is still not at the goal, optimize dosages or add medications. Assess whether or not the patient is adhering to meds, advise for self-monitoring at home, consider a potential secondary cause. If none work, refer to HTN specialist.
- If at any point the patient is at their goal, encourage self-monitoring, have them visit clinic regularly and alert office with side effects or BP elevation.
What are the main five non-pharmacological lifestyle modifications that can be made for hypertension?
1 - Reduce weight 2 - Adopt the DASH eating plan 3 - Lower sodium intake 4 - Get physical activity 5 - Moderation of alcohol consumption
What is the DASH eating plan?
D = dietary A = approach to S = stop H = hypertension
Consume a diet rich in fruits, vegetables and low-fat dairy products with a reduced content of saturated and total fat
Describe the baroreceptor reflex in hypertension
Chronic hypertension “resets” the baroreflex such that the increased pressure is considered normal
What do you need to consider in terms of the baroreflex when prescribing antihypertensive agents?
- With each antihypertensive agent, one must consider the effects on the baroreflex
- Attempts to lower the pressure activates the reflex mechanisms that act to raise the pressure
What does it mean to say that when the BP is lowered, mechanisms will be activated to raise pressure?
- Sodium and water retention will be initiated by the kidneys
- Sympathetically-induced increases in peripheral vascular resistance, heart rate and cardiac output will occur
How do you calculate the mean arterial pressure?
MAP = CO x TPR
How do you calculate cardiac output?
CO = SV x HR
Why is it important to know these equations?
All antihypertensive agents work to reduces one or more of these components. Some have additional effects on the central nervous system.
According to JNC7 algorithm treatment method, what is a first line regimen?
First-line regimens are therapies proven to reduce the risk of cardiovascular events in the given patient situation. ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; CCB, calcium channel blocker
What five patient conditions would give you a compelling indication for a specific drug therapy?
- Diabetic patients
- Chronic kidney disease patients
- Coronary artery disease patients
- Left ventricular dysfunction patients
- Previous ischemic stroke patients
What if your patient does not have a compelling indication?
Single drug
- ACEi
- ARB
- CCB
- Thiazide
Two drugs
- ACEi or ARB with CCB
- ACEi or ARB with thiazide
- CCB with thiazide
What if your patient has diabetes?
First line
- ACEi or ARB
Add on
- Thiazide
- Then beta blocker and/or CCB
What if your patient has chronic kidney disease?
First line
- ACEi or ARB
What if your patient has coronary artery disease?
First line
- Beta blocker and…
- ACEi or ARB
Add on
- Aldosterone antagonist, CCB and/or thiazide
What if your patient has left ventricular dysfunction?
First line
- Diuretic
- ACEi or ARB and
- Beta blocker
Add on
- Aldosterone antagonist and/or hydralazine with isosorbide dinitrate
What if your patient has previous ischemic stroke?
First line
- ACEi with or without thiazide
Briefly describe the RAAS (renin-angiotensin-aldosterone system)
- Angiotensinogen is cleaved into angiotensin I by renin
- Angiotensin I is cleaved into angiotensin II by ACE
- Angiotensin II causes aldosterone release
- Aldosterone causes renal retention of Na+
- This increases the circulating blood volume
When treating a resistant hypertensive patient, what substance may be interfering with treatment?
EXCESSIVE DIETARY SODIUM
- Sodium reduction needs to be integrated into the plan
- Refer to nutritionist
Why are diuretics necessary in hypertension treatment?
RHTN patients with or without evidence of aldosterone excess have been shown to be fluid overloaded despite treatment with an RAS blocker and a diuretic.
What type of diuretic is preferred?
Thiazide-type
Which drug is a preferred thiazide diuretic?
Chlorthalidone
- it is the agent used in major outcome trials that showed benefit
- Chlorthalidone is more potent, has a longer duration of action, and produces greater BP reductions than hydrochlorothiazide
What does spironalactone do when added into a therapy plan?
Spironolactone produces robust BP reductions when added to a regimen that includes an RAS blocker (ACE inhibitor or ARB).
It is safe and generally well tolerated
What are two other drugs can be added to a resistant hypertensive treatment plan?
Doxazosin
- Useful when added to multidrug antihypertensive regimens in RHTN
- Shown to reduce BP by 33/19 points
Amiloride
- Directly blocks the epithelial sodium channel (ENaC)
- Shown to reduce BP by 31/15 points when combined with hydrochlorothiazide
What is renal sympathetic denervation as a treatment for resistant hypertension?
- Renal somatic afferent nerve activity is a source of elevated central sympathetic tone
- Selective renal artery catheterization –> low-power radiofrequency treatments along the length of both main renal arteries to denervate both kidneys have been shown to be effective in reducing BP in patients with RHTN
What is baroreflex activation therapy for patients with resistant hypertension?
- Increased baroreceptor firing = decreased sympathetic drive
- Electrical stimulation of the baroreceptors using an implantable device can cause up to a 35mmHg SBP drop
Which drugs are acceptable for the treatment of hypertension in pregnancy?
- Methyldopa
- Labetalol
- Long-acting nifedipine
- Hydralazine
- Metoprolol
Which drugs are generally avoided for the treatment of hypertension during pregnancy?
- Diuretics
- Atenolol
- Nitroprusside
Which drugs are strictly contradicted during pregnancy?
- ACE inhibitors
- Angiotensin receptor antagonists