Hypertension - 4

What is normal BP?

systolic <120 mmHg and diastolic <80 mmHg

What is elevated BP?

systolic 120-129 mmHg and diastolic <80 mmHg

What is stage 1 hypertension BP?

systolic 130 to 139 mmHg or diastolic 80 to 89 mmHg

What is stage 2 hypertension BP?

systolic 140+ mmHg or diastolic 90+ mmHg

What is systolic BP?

peak pressure in the arteries near the end of systole (top number)

What is diastolic BP?

resting pressure in the arteries during diastole (bottom number)

What is target SBP / DBP?

130/80

What is blood pressure (BP)?

pressure that occurs when blood pushes against the walls of your arteries

What is cardiac output (CO)?

amount of blood ejected by each ventricle in one minute

What is cardiac output (CO) equal to?

stroke volume (SV) x heart rate (HR)

What is systemic vascular resistance (SVR)?

the resistance to blood flow in the systemic circulation

What is the equation for blood pressure (BP)?

blood pressure (BP) = cardiac output (CO) x systemic vascular resistance (SVR)

What is preload?

the volume of blood in the ventricles resulting in the stretch on the ventricles at the end of diastole

A higher filling volume _____ SV and ____ BP

increases, increases

What is contractility?

the force of the heart muscle contraction

A stronger contraction leads to ____ SV and ____ BP

increased, increased

What is afterload?

the resistance (pressure) the heart must overcome to circulate blood around the body

Higher resistance _____ SV and _____ BP

decreases, increases

How is preload approximated?

by end-diastolic volume (EDV) via:

• ventricular filling

• force of contraction

• fluid/blood volume

What does the Frank Starling Law associate with?

preload

What does the Frank Starling Law say?

• increased filling → myocardial stretch → stronger contraction

• stretch improves contraction up to an optimal point

• overstretching decreases contraction

Analogy associated with preload

rubber band; optimal stretch = most productive snap

What are the major contributors to afterload?

• ventricular wall tension

• systemic vascular resistance (SVR)

• aortic elasticity

• arterial pressure

Effect of increased afterload

• decreased SV

• increased BP

What type of effect does contractility have on the ANS?

inotropic (inc. contractability = (+) inotrope)

What are the pacemakers of the heart?

• SA node

• AV node

• Purkinje fibers

What is the bpm of the SA node?

60-100 bpm

What is the bpm of the AV node?

40-60 bpm

What is the bpm of the Purkinje fibers?

20-40 bpm

What effect does heart rate have on the ANS?

chronotropic (inc. HR = (+) chronotrope)

What is systemic vascular resistance (SVR)?

resistance to blood flow in systemic circulation

Basic rules of systemic vascular resistance (SVR)

• vasoconstriction = increased resistance = decreased flow

• vasodilation = decreased resistance = increased flow

What are ways that SVR can be regulated in the body?

• neural

  • baroreceptors (pressure/stretch)

  • chemoreceptors (pH, CO2, O2)

• autonomic

  • sympathetic tone (vasoconstriction/vasodilation)

  • parasympathetic (vasodilation of select organs)

• paracrine

  • nitric oxide, bradykinin, prostaglandins

  • smooth muscle relaxation (vasodilation)

How is hypertension diagnosed?

based on average of 2+ readings on 2+ occasions

What are types of out-of-office BP confirmation methods recommended?

• home BP monitoring (HBPM)

• ambulatory BP monitoring (ABPM)

First and foremost for hypertensive PTs

All PT with hypertension should undergo lifestyle modifications

What are lifestyle modifications associated with hypertension treatment?

• weight loss

• dietary salt restriction

• dietary approaches to stop hypertension (DASH) diet

• exercise

• limited alcohol intake

• smoking cessation

• stress reduction

Lifestyle modifications: weight loss

• goal = at least 5% of body weight reduction

• loss of 1 pound = 1 mmHg decreased in BP

Lifestyle modifications: dietary salt restriction

• multiple recommendations

• <1.5-2 grams daily

Lifestyle modifications: DASH diet

• high in:

  • vegetables

  • fruits

  • low-fat dairy products

  • whole grains

  • poultry

  • fish

• low in:

  • sweets

  • sugar-sweetened beverages

  • red meats

Lifestyle modifications: exercise

• moderate-intensity aerobic exercise approx. 150 min/week

• include resistance training >/= 2 days/week

Lifestyle modifications: limited alcohol intake

• abstinence

• </= 1 drink/day for women

• </= 1-2 drinks/day for men

Lifestyle modifications: smoking cessation

• temporary increases in BP and HR

• long-term causes vessel damage and arterial stiffening

Lifestyle modifications: stress reduction

• breathing control

• meditation

What type of hypertension can potentially be managed with just lifestyle changes? What does that entail?

stage 1 HTN

• no diabetes

• no coronary artery disease

• no chronic renal disease

• age < 65 yrs

• re-access every 3-6 months!

When to start medication for a PT with stage 1 HTN

• established ASCVD10-year risk >/=10%

• chronic kidney disease

• diabetes

• age >/= 65 yrs

When to start medication for a PT with stage 2 HTN

• start BP medications for all PTs

• recommend 1-2 first-line agents

  • potential single-pill combination

What is the goal BP for most adults?

<130/80 mmHg

What does ACC stand for?

American College of Cardiology

What does AHA stand for?

American Heart Association

What does JNC 8 stand for?

Joint National Committee 8th guideline

What does AAFP stand for?

American Academy of Family Physicians

What are the recommended 1st line medications for HTN?

• thiazide diuretics

• ACEi

• ARBs

• CCB

Mechanism of thiazide diuretics

inhibits Na+ reabsorption in distal tubules (kidneys) causing increased excretion of Na+, water, K+, and H+

Physiological effects of thiazide diuretics

• increased Na+ and water excretion in urine

• decreased intravascular volume

• decreased preload

• *initially: decreased CO

• *overtime: decreased SVR due to reduced Na+ in vascular smooth muscle

Why are thiazide diuretics 1st line?

• strongest outcome evidence for stroke and HF prevention

• effective in most populations

Names of thiazide diuretics and their prefix

• hydrochlorothiazide (Microzide)

• chlorthalidone (Thalitone)

CHLOR-

What are side effect for all BP meds?

• hypotension/orthostatic hypotension

• headache, dizziness, fatigue

Side effects of thiazide diuretics

• hypokalemia, hyponatremia, hypomagnesemia

• hypercalcemia, hyperglycemia

• photosensitivity

• renal failure

• glaucoma

• gout

• pancreatitis

Contraindications for thiazide diuretics

• known hypersensitivity/anaphylaxis

• anuria (ex. dialysis PT)

Warnings for thiazide diuretics

• PT may require K+ supplementation

  • should monitor electrolytes

• monitor in PT w/ renal disease

What does CCB stand for?

calcium channel blockers

What is the main CCB?

dihydropyridine

• non-dihydropyridine not used for HTN specifically

Mechanism of CCBs

inhibits Ca2+ ion from entering certain areas of vascular smooth muscle and myocardium during depolarization, producing a relaxation of vascular smooth muscle causing vasodilation

Physiologic effects of CCBs

• decreased calcium entry = smooth muscle relaxation

• arteriolar vasodilation

• large reduction in SVR

How do CCBs lower BP?

almost entirely through decreased SVR

• minimal effect on HR or contractility

Why are CCBs first line?

• highly effective across age and race

• particularly effective in:

  • older adults

  • black PTs

• strong strong prevention data

Names of CCBs and their suffix

• nifedipine (Procardia)

• amlodipine (Norvasc)

• nicardipine (Cardene)

-DIPINE

Side effects of CCBs

• peripheral edema

• reflex tachycardia/palpitations

• facial flushing

Contraindications for CCBs

• anaphylactic shock

• severe heart failure

• hypotension

Mechanism of ACEi

prevents conversion of angiotensin 1 to angiotensin 2, blocking vasoconstriction

What cause vasodilation in the body?

bradykinins

Physiologic effects of ACEi

• vasodilation leads to decreased SVR

• decreased aldosterone leads to decreased Na+ and water retention, decreasing the preload

• improved endothelial function

• reduced maladaptive cardiac and vascular remodeling

How do ACEi lower BP?

decreasing SVR

• minor effect: decrease CO through volume reduction (decreased preload)

Why are ACEi first line?

• proven reduction in AMI, stroke, heart failure, and CKD progression

• disease-modifying, not just BP-lowering

Names of ACEis and their suffix

• benazepril (Lotensin)

• enalapril (Vasotec)

• lisinopril (Prinivil, Zestril) → most common

• quinapril (Accupril)

• ramipril (Altace)

-PRIL

Side effects of ACEi

• angioedema

• dry cough

• hyperkalemia

• increased creatinine

Contraindications for ACEi

• anaphylazis/hypersensitivity

• angioedema

• renal failure/renal artery stenosis

• hyperkalemia

• hypotension

• PREGNANCY!!!

Mechanism of ARBs

interfere with the RAAS by inhibiting the action of angiotensin 2 (vasconstriction)

Physiological effects of ARBs

• vasodilation leads to decreased SVR

• decreased aldosterone leads to decreaed volume/preload

Why are ARBs first line?

• same BP and CV outcome benefits as ACEi

• better tolerated vs ACEi

  • less cough

  • less angioedema

Names of ARBs and their suffix

• azilsartan (Edarbi)

• candesartan (Atacand)

• irbesartan (avapro)

• losartan (Cozaar) → most common

• olmesartan (Benicar)

• telmisartan (Micardis)

• valsartan (Diovan)

-SARTAN

Side effects of ARBs

• angioedema/dry cough (less than ACEi)

• hyperkalemia

• increased creatinine

Contraindications of ARBs

• anaphylaxis/hypersensitivity

• angioedema (from previous ACEi use)

• renal failure/renal artery stenosis

• hyperkalemia

• hypotension

• PREGNANCY

When should BBs be given?

• after an acute MI

• CAD

• to stable PT with HF (HFrEF only)

What do BBs do following an AMI and in HF?

reduce mortality

What are BBs usually combined with?

ACEi

Mechanism of beta-blockers

• inhibits beta-adrenergic receptors

  • blocks the harmful effects of chronic SNS activation to protect the heart from excessive adrenaline

  • decreases inotrophy (contractility) & chronotrophy (HR)

What do cardio-selective BBs block and effect?

• Beta 1

• heart

What do non-slective BBs block and effect?

• Beta 1 and 2

• heart, lungs, kidneys, GI tract, liver, uterus, and vascular smooth muscle

What BB is newer/second generation?

cardio-selective BB

Physiological effects of BBs

• decreased HR

• decreased myocardial O2 demand

• improved diastolic function

• prevents arrhythmias

• promotes reverse remodeling of left ventricle over time

Names of non-selective 1st gen BB and their suffix

• nadolol (Corgard)

• propranolol (Inderal)

• timolol maleate (Blocadren)

• sotalol hydrochloride (Betapace)

-OLOL

*No Point To Select

Names of cardio-selective 2nd gen BB and their suffix

• atenolol (Tenormin)

• bisoprolol fumarate (Zebata)

• esmolol hydrochloride (Brevibloc)

• metorpolol (tartrate = Lopressor, succinate = Toprol XL)

• nebivolol (Bystolic)

-OLOL
*select MEN with ABs

Side effects of BBs

• bradycardia

• fatigue

• bronchospasm/respiratory distress

• masks hypoglycemia in PT w/ diabetes!!!

Contraindications for BBs

• hypersensitivity/anaphylaxis

• bradycardia

• 2nd/3rd degree AV blood

• hypotension

What are some compelling indications for use of BBs in HTN?

• CAD

• post-MI

• HFrEF

• tachyarrhythmias (a-fib)

What is the mechanism of alpha & beta blockers?

blocks both alpha 1 and beta 1 & 2 receptors

Names of alpha & beta blockers and their suffix

• labetalol (Normodyne)

  • safer in pregnancy

• carvedilol (Coreg)

-LOL

Physiological effect of alpha & beta blockers

vasodilation (alpha) in addition to decreased HR (beta)