Essential Hypertension Review| USMLE Step 2

Cardiology
HYPERTENSION
USMLE Step 2 Review
Marc Imhotep Cray, M.D.
BMS and CK Teacher
http://www.imhotepvirtualmedsch.com/

Cardiology| Hypertensive Vascular Disease
Topics Covered
2
 Definition
 Classification
 BMS Concepts
 RAAS
 Causal Conditions
 Target Organ Damage
 Approach
 Management
 HTN in Elderly

DEFINITION of HTN
• A BP of >140/90 mm Hg on two separate occasions
• If there is end-organ damage, diagnosis is made on
the first visit
3
HY Points:
HTN is not diagnosed until two separate measurements on two separate
occasions are above 140/90 mm Hg (except in pregnancy, when
preeclampsia may be cause of hypertension)
Also, if hypertension is severe (>210 mm Hg systolic, >120 mm Hg diastolic,
or end-organ effects), immediate treatment with medication is warranted

JNC Classification of HTN
4
National High Blood Pressure Education Program. The Seventh Report of the Joint National
Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.
Bethesda (MD): National Heart, Lung, and Blood Institute (US); 2004 Aug. Classification of
Blood Pressure.
Available at http://www.ncbi.nlm.nih.gov/books/NBK9633/

BMS CONCEPTS OF HTN
Effect of CO and SVR on BP:
CO = HR × SV
MAP = TPR × CO
BP ∼ CO × TPR
CO = MAP / TPR
MAP = dBP + 1 / 3 pulse pressure
AUTOREGULATION
↑ CO → ↑ MAP, detected by aortic and carotid baroreceptors →
vasodilation → ↓ TPR and hence ↓ CO (to balance the initial ↑ CO)
PRESSURE NATRIURESIS
↑ MAP = ↑ renal perfusion, ↑ GFR, and ↓ aldosterone → ↑ Na +
H2O excretion (natriuresis)
5

6
 RAAS plays an important role in regulating blood volume and
systemic vascular resistance, which together influence cardiac
output and arterial pressure
 Three important components to this system: 1) renin,
2) angiotensin, and 3) aldosterone
• Renin, which is primarily released by kidneys, stimulates
formation of angiotensin in blood and tissues, which in turn
stimulates the release of aldosterone from the adrenal cortex
Renin-angiotensin-aldosterone
system (RAAS)

RAAS cont.
7
 Renin is a proteolytic enzyme that is released into the
circulation primarily by the kidneys.
Its release is stimulated by:
i. sympathetic nerve activation (acting through β1-
adrenoceptors)
ii. renal artery hypotension (caused by systemic hypotension
or renal artery stenosis)
iii. decreased sodium delivery to distal tubules of kidney

RAAS schematic
8
http://en.wikipedia.org/wiki/File:Renin-angiotensin-aldosterone_system.png

CAUSAL CONDITIONS of HTN
1. 1◦ (essential HTN—95% of cases)
2. 2◦ HTN
• Renal/vascular (↑ CO)
• RF, polycystic kidney disease, CoA, RAS
• Endocrine (↑ SVR)
• Hyperthyroidism, adrenal adenoma (↑ aldosterone, ↑ cortisone),
pheochromocytoma, Hyperparathyroidism
Reversible RF: obesity, poor dietary habits, high Na+ intake,
sedentary lifestyle, high EtOH and/or coffee consumption, high
stress, high normal BP, illicit drug use (e.g., cocaine),
herbal med (e.g., ma huang, ginseng, licorice, ginger)
9

Target Organ Damage in HTN
10
Cerebrovascular disease
• TIA
• Ischemic or hemorrhagic stroke
• Vascular dementia
Hypertensive retinopathy
LV dysfunction
CAD
• MI
• Angina
• CHF
CKD
• Hypertensive nephropathy
• Albuminuria
Peripheral artery disease
• Intermittent claudication

APPROACH
Hx
• Age of onset, duration, prior Rx and response, Hx of refractory
HTN? associated Sx (chest pain, palpitations, SOB, renal problems,
headaches, diaphoresis, polyuria, hematuria, edema), Hx, or
symptom of sleep apnea
• Family Hx, meds, diet, coffee intake, and EtOH
• End-organ damage
(stroke/TIA, MI, CHF, renal disease, retinal disease), CV risk
stratification
• Elicit hypertensive emergency (hypertensive encephalopathy,
strokes, dissecting thoracic aortic aneurysm, malignant HTN, acute
LV failure, acute glomerulonephritis)
11

APPROACH
PE
• BP measurement with calibrated instrument and appropriate
cuff size
• Fundi (copper wire, cotton wool spots, AV nicking,
papilledema)
• Complete CV exam (clubbing, cyanosis, peripheral pulses,
bruits, JVP, apex beat, parasternal heave, heart sounds and
murmurs, compare U/E and L/E BP),
• Lungs auscultation,
• Abdo exam for renal mass and bruits, edema, weight
12

APPROACH
Standard Workup
Electrolytes, BUN, CR, fasting gluc., U/A, lipid profile (fasting total
cholesterol, HDL, LDL, triglycerides), EKG (to evaluate LVH s)
13

APPROACH
2◦ Causes Workup
1. Renal and vascular
• Renovascular (older pt, Hx of atherosclerosis, renal artery bruit)
• Captopril renal scan/duplex U/S, MRI, angiography
• Unilateral RAS: normal Cr
• Bilateral RAS: hypervolemia, ↑ Cr
• Renal parenchymal
• BUN, Cr, Cr clearance
• CoA
• ↓ LE pulses, radiofemoral delay, systolic murmur, LVH, rib
notching on CXR
• ECHO, aortogram
2. Endocrine
• TSH, cortical, urinary VMA, PTH, aldosterone, renin, renin /
aldosterone ratio
14

MANAGEMENT
15
Annual F/U with high normal BP is recommended as 40% of pts
with sBP 130 to 39 mm Hg or dBP 85 to 89 mm Hg develop HTN
in 2 years
Home BP monitoring
Goal ↓ BP to <140/90 mm Hg; and if pt has diabetes or renal
disease, BP <130/80 mm Hg
Pharmacologic Rx
• Select med with minimal or Ø adverse effects on diabetes,
asthma, and that benefits CHF or myocardial ischemia
• Initiate pharmacologic Rx for hypertensive pt refractory to
lifestyle s or pre-HTN + diabetes/renal disease

MANAGEMENT
16
HTN Alone
Thiazide diuretics, β-blockers, ACEIs, ARBs, long-acting CCBs as
first-line Rx
• If still Ø response to Rx despite max tolerated dose or Rx-
related adverse effect, add CCB/ARB/α-receptor blocker/centrally
acting agents (methyldopa)
HY Point:
For HTN that is nonresponsive to Rx, consider noncompliance, 2◦
HTN, drug interactions
ACEIs and ARBs are contraindicated in pregnancy
β-Blockers are not recommended for pts older than 60 years without
indication
Avoid diuretic-induced hypokalemia by using K+ sparing agent

Antihypertensives in Pt with
Other Comorbidities
17
Whalen KL, Stewart RD. Pharmacologic management of hypertension in patients
with diabetes. Am Fam Physician. 2008 Dec 1;78(11):1277-82.
Available at http://www.aafp.org/afp/2008/1201/p1277.html#abstract
Which agent you choose is often based on comorbidities

Exogenous Aggravators of HTN
18
Prescription Drugs
• NSAIDs, including coxibs
• OCP and sex hormones
• Corticosteroids and anabolic steroids
• Vasoconstricting / sympathomimetics
• Calcineurin inhibitors
(cyclosporin, tacrolimus)
• EPO and analogs
• MAOIs
• Midodrine
Other
• Salt
• Excessive EtOH use
• Sleep apnea
• Licorice root
• Stimulants including
cocaine
HY Point:
Urinary Albumin Secretion
Identify urinary albumin secretion for DM and CKD:
Rx differs without proteinuria
albumin/ creatinine ratio (ACR) >30 mg/mmol is AbN

Lifestyle Therapies in HTN
19
Refer to United States food guide

HYPERTENSION IN ELDERLY
20
DEFINITION
• A BP of >140/90 mm Hg
• Isolated systolic HTN (sBP >140; dBP <90) is more common in
elderly population
• Prevalence may reach 60% to 80% in pts aged 60 years and older
BMS: Factors that contribute to ↑ prevalence of HTN in elderly:
↓ Compliance of arterial wall
↓ NO dependent arterial vasodilation
↓ Numbers of functioning nephrons
↑ Collagen, ↑ vascular thickening,
↓ elasticity
↓ CV physiological reservoir
Nikolaos Lionakis et. al. Hypertension in the elderly World J Cardiol. May 26,
2012; 4(5): 135–147. Published online May 26, 2012.
Available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3364500/

BMS of HTN in Elderly
21
• Age-related s in aortic vascular property
• ↑ Age → progressive thickening of arterial walls—predominantly
in the intimal
layer→↑intimal to medial thickness ratio
• ↑ Fragmentation and depletion of arterial elastin coupled with
medial deposition of matrix metalloproteins and collagen
• Collectively, this leads to thicker and stiffer arteries, predominantly
central elastic arteries
• In elderly, ↑ sBP is characterized by widened arterial pulse
pressure or s in vascular morphology associated with ↑ age →
small artery constriction that ↑ reflected component of the pulse
wave
• Large artery stiffening that ↑ velocity of reflected wave, where it
moves from diastole to systole hence ↑ sBP

HTN in Elderly cont.
22
CAUSAL CONDITIONS
• 1◦ HTN
• 2◦ HTN
• Med related (Na+ retaining agents e.g.,mineralocorticoids, anabolic
steroids, NSAIDs, antidepressants, sympathomimetics e.g.,
pseudoephedrine, herbal agents)
• Endocrine: thyrotoxicosis, pheochromocytoma, Cushing disease,
1◦ aldosteronism, hyperparathyroidism, hyper/hypothyroidism
• Renal: renovascular disease (RAS), renal parenchymal disease
• Vascular: aortic coarctation
• Sleep apnea
Other causes
• White coat HTN
• Pseudohypertension also prevalent in the elderly population due
to thickening and calcification of the arteries

23
APPROACH
Hx
In addition to usual Hx taking for HTN:
• Meds: Prescribed, OTC and herbal drugs
• Past medical history: DM, CRF, pre-HTN, hyperlipidemia, CAD
• Social Hx: smoking, EtOH intake, dietary habits (↑ salt &↑ fat diet)
PE
• Vitals: BP (compare for both arms), weight, height, BMI, waist
circumference (assess for MS)
• Head and Neck: funduscopy for retinal s, thyroid exam, JVP, carotid
bruit
• Chest: signs of CHF, palpable murmur
• CV exam: murmurs, Abdo aorta bruit, renal artery bruit,
Abdo. aorta aneurysm

24
MANAGEMENT
sBP and pulse pressure should be regarded as major
predictor of outcome
• Rx should be initiated when sBP >160 mm Hg or >140 mm Hg
when pt has other RF like diabetes and smoking
• Nonpharmacologic Rx: lifestyle modification, achieve target
BMI through diet and exercise, Na restriction, cessation of
smoking, judicious consumption of EtOH
• Pharmacologic Rx: initiated if the above is inadequate
• Benefit in treating systolic HTN in the elderly is two to four
times greater than in younger pt with 1◦ HTN

HTN in Elderly Mx cont.
25
• Thiazide diuretic-First-line choice for elderly pt
• Use lower doses (half of what is usually used in younger
population) to minimize side effects like postural
hypotension due to sluggish autoregulation in elderly
population
• Periodically monitor lytes; hypokalemia may negate CV benefit
• Dihydropyridines (nifedipine ) may also be used as an
alternative
William JE, Black HR Treatment of Hypertension in the Elderly
Am J Geriatr Cardiol. 2002;11(1)
Available at http://www.medscape.com/viewarticle/423503_1

Further Study
26
 Chobanian AV, Bakris GL, Black HR, et al. The Seventh Report of the Joint
National Committee on Prevention, Detection, Evaluation, and Treatment of
High Blood Pressure: The JNC 7 Report. JAMA. 2003;289(19):2560-2571.
Available at http://jama.jamanetwork.com/article.aspx?articleid=196589
 Kotchen TA Hypertensive Vascular Disease Ch. 247
In Kasper DL, Braunwald E, Fauci AS, et al. Harrison's Principles of Internal
Medicine (18th ed.). New York, NY: McGraw-Hill 2013. pp. 2040–58.
For more like this visit IVMS’s latest Website/ Blog
http://drimhotepmd.wordpress.com/
 Medscape Meena SM Hypertension
Available at http://emedicine.medscape.com/article/241381-overview
 Nikolaos Lionakis et. al. Hypertension in the elderly World J Cardiol. May 26,
2012; 4(5): 135–147. Published online May 26, 2012.
Available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3364500/

Essential Hypertension Review| USMLE Step 2

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Essential Hypertension Review| USMLE Step 2