Definition and diagnosis of HTN; Aortic Stenosis

Question 1

Definition and Classification of Hypertension

Answer 1

• Hypertension is a disease where there is consistent elevation of SBP and DBP
• In Adults, SBP > 140mmHg AND/OR DBP > 90mmHg
• In Children, > 95th percentile for blood pressure or > 130mmHg [for children < 13 years old], while in children > 13 years old, SBP > 130mmHg AND/OR DBP > 90mmHg

Classification: [According to 2020 ISH guidelines]
- Normal SBP < 130 mmHg and DBP < 85 mmHg
- Elevated SBP 130-139 mmHG and DBP 85-89 mmHg
- Stage 1 SBP 140-159 mmHg and DBP 90-99 mmHg
- Stage 2 SBP > 160 mmHg and DBP > 100mmHg

Question 2

Etiology of Hypertension

Answer 2

Broadly divided into Primary and Seconday

Primary HTN:
- Hypertension due to multiactorial development [multiple risk factors that work together than alone] and not due to a particular reason
- Directly related to Total Peripherial Resistance and Cardiac Output

Secondary HTN:
- Hypertension due to an underlying disease or disorder

Question 3

Risk Factors for Primary HTN

Answer 3

Non-modifiable:
- Race and Ethnicity
- Positive Family History
- Advanced age

Modifiable:
- Overweight and Obesity
- Uncontrolled diabetes
- Smoking
- Excessive Alcohol intake
- Diet high in sodium and low in potassium
- Physical inactivity
- Psychological stress

Question 4

RECENT acronym

Causes of Secondary HTN

Answer 4

• Renal: Renal artery stenosis, Glomerulonephritis
• Endocrine: Cushings Syndrome, Hyperthyroidism, Conn Syndrome
• Coarctation of Aorta
• Estrogen: Oral contaceptives
• Neurological: Raised ICP, psychostimulant usage [eg - cocaine]
• Treatment: Glucocorticoids, NSAIDs

Obstructive Sleep apnea is another cause of Secondary HTN

Question 5

Complications of HTN

Answer 5

Cardiovascular:
- LV Hypertrophy
- Hypertrophic Cardiomyopathy
- Dilated Cardiomyopathy
- Congestive HF
- AFib
- Aortic Aneurysm
- Aortic Dissection
- CAD
- PAD
- Atherosclerosis

Brain:
- Stroke [Ischemic or Hemorrhagic]
- TIA
- Memory loss and other cognitive changes
- Subcortical Leukoencephalopathy

Kidneys:
- Hypertensive Nephrosclerosis
- Chronic Kidney Disease

Eye:
- Hypertensive Retinopathy [Cotton wool spots, Papilledema, Retinal hemmorhages, Arteriovenous nicking, Optic atrophy, Elschnig spots]

Question 6

Diagnostic Approach to HTN

Answer 6

On regular health checkups, BP is measured in everyone. Thus any screening of BP should be done during regular physical checkups and the patient must be educated on measuring blood pressure at home AND coming for regular health checkups especially people older than 40 years old AND/OR people with HTN risk factors.

In-office measurement:
- If elevated, repeat on both arms
- Elevated average BP in atleast 2 readings on atleast 2 separate occasions

Out-of-Office measurement:
- ABPM aka Ambulatory Blood Pressure Monitoring [over 12-24 hours while patient goes about their normal day] is preffered and diagnostic
- HBPM aka Home Blood Pressure Monitory where patients are properly taught about right cuff size and how to measure BP accurately

Question 7

Evaluation of new HTN in patients

Focus on End-organ damage, Secondary HTN and ASCVD risk assessment

Answer 7

Physical Exam and Patient History:
- BMI and Waist circumference
- Neurologic examination
- Cardiac examination [including ausculation of Carotid arteries and Palpation of Peripheral pulses]

Routine Tests:
- Fasting Blood Glucose
- Serum Na, K, Ca2+ levels [to establish baselines before anti-HTN therapy]
- RFTs [Serum creatinine, eGFR]
- CBC
- TSH [screen for Hyperthyroidism]
- Lipid Profile [HDL, LDL, triglyceride levels]
- Urinalysis
- ECG

Additional Tests:
- HbA1c
- Fundoscopy
- LFTs
- Serum Uric Acid
- Echocardiogram

All patients with new HTN should have Hyperaldosteronism as part of routine screening

All patients < 30 years old with elevated Brachial BP should also get Thigh BP measured to rule out Coarctation of Aorta

All patients should get an Orthostatic Hypotension assessment

Question 8

Epidemiology and Etiology of Aortic Stenosis

Answer 8

Epidemiology:
- Prevalance increases with age
- Prevalence higher in industrialized countries
- Post-rheumatic AS more common in 3rd world countries with low antibiotic usage
- Frequently associated with Aortic Regurgitation

Etiology:
- Degenerative Calcifications/Sclerosis [most common in older patients > 65 years old; Calcifications and fibrosis]
- Bicuspid Aortic Valve [Congenital, most common in patients < 65 years old; 3:1 predominantly male; predisposes valve to dystrophic calcifications and degenerations]
- Williams Syndrome [Supravalvular Aortic Stenosis; Gene deletions on Chromosome 7 including Elastin gene, leading to Facial and CV abnormalities, developmental delays]
- Post-Rheumatic Disease AS
- Subvalvular [HOCM, disproportionate hypertrophy of ventricular septa blocking aortic outflow track especially on exertion]

Question 9

Clinical Features of Aortic Stenosis

Answer 9

Signs and Symptoms: Classic triad of symptoms
- Exertional Dyspnea
- Syncope
- Angina Pectoris
- In infants wheezing and difficulty feeding

Physical Exam findings:
- Low BP amplitude
- Low pulse pressure
- Pulsus parvus et tardus

Auscultation:
- Harsh Crescendo-Decrescendo, late Systolic Ejection murmur radiating bilaterally to carotids
- Heard best on 2nd intercoastal space on right
- Valsalva maneuver decreases intensity of murmur
- Soft S2 [due to desyned closing of aortic and pulmonary valves, softer closing of aortic valve]
- S4 best heard at apex [LVH leading to atrium forcefully squeexing blood into non-compliant LV]
- Early systolic Ejection click [abrupt stop of aortic valve leaflets due to stiffening]

Question 10

Classification of Aortic Stenosis

Answer 10

According to AHA/ACC, AS is divided into:
- Stage A = normal AVA; normal Transaortic velocity; normal gradient pressure
- Stage B = 1,0 - 2,9 cmsq AVA; 2,0-3,9 m/sec velocity; 10-39 mmHg gradient pressure
- Stage C1 = Asymptomatic severe AS with LVEF normal
- Stage C2 = Asymptomatic severe AS with LV dysdunction [< 50%]
- Stage D = Symptomatic severe [has further 3 subdivisions]

AVA - Aortic Valve Area [3-4 cmsq normal]

Stages C1, C2 and D have < 1,0 cmsq AVA; > 4,0 m/sec velocity; > 40mmHg gradient pressure

Question 11

Diagnostic approach and methods for AS

Answer 11

• ECG for patients complaining of angina and dyspnea [may show LV and LA abnormalities]
• Echocardiography: TTE gold standard for dx and severity of AS; TEE second line and for confirmation of TTE findings, or operative planning

Supportive findings in Echo:
- Calcifications and narrowing of AS
- Increased mean gradient pressure and transvalvular velocity
- Sings of cardiac remodelling [concentric LV hypertrophy]

Other methods:
- Chest Xray: Mainly for ddx of dyspnea, however we could find Visible calcifications in aortic valve, Narrowing of retrocardiac space [lat view], signs of cardiac remodelling and associated HF/congestion/LVH
- Lab studies: non specific, BNP/NT-proBNP; Troponin T/I

Question 12

Critical Complications of AS and general rules to manage

Answer 12

• Cardiogenic shock
• Acute HF
• AFib with RVR

General rules to manage hemodynamic instability of AS:
- Maintain Preload
- Avoid Iatrogenic Hypotension
- Maintain normal HR and Sinus Rhythm
- Consider focused cardiac US to help guide resuscitation
- Diuretics for Hypervolemia
- Nitrates and PPV for Flash pulmonary edema
- Judicious use of fluid for Hypovolemia
- Inoconstrictor drugs at lowest possible dose for Persistent hypotension
- Dobutamine for Unstable bradycardia
- Electrocardioversion for Unstable tachycardia

Do not delay surgery for Critical Complications of AS

Question 13

Management and Treatment for AS

Answer 13

Approach:
- Supportive for asymptomatic or mild-to-moderate AS patients [Conservative therapy]
- Aortic Valve Replacement for symptomatic and/or severe AS. Can be Open-surgery or Catheter based
- Manage comorbidities like HTN, diabetes, hyperlipidemia
- Promptly identify and treat critical complications of AS [do not delay surgical intervention]
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Supportive Care
Comodbidities:
- Ace inhibitors, Beta blockers, Diuretics for HTN
- Statins and other treatments for AS [statins unlikely to prevent progress of AS]
- Metformin and lifestyle modifications for Diabetes Mellitus

Echocardiography monitoring:
- Monitor changes in regular follow-ups in asymptomatic patients

Prophylactic Antibiotics:
- Rheumatic Heart diseases
- Dental procedures [infective endocarditis]

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AVR and repair
- For asymptomatic patients with severe AS [Stage C2 AS or undergoing cardiac surgery for other indications]
- Symptomatic patients with severe, high gradient AS [Stage D]
- Surgical AVR [for patients < 65 years old with > 20 years life expectancy and low to moderate surgical risk]
- Transcatheter AVR [for patients > 80 years old with < 10 years life expectancy and high or prohibitive surgical risk + predicted survival > 12 months]
- Percutaneous Ballon Valvuloplasty [in children, adolescents and young adults with no valve calcifications
- Antithrombotic therapy post surgery lifelong [mainly warfarin and ASA combinations]

Consider surgery for Stages C1, C2 and D

Based on criteria and age, consider AVR for young patients with long survival

Surgical indications include the Triad symptoms for AS

Question 14

Complications of AVR in AS

Answer 14

• Vascular complications [thromboembolism/stroke]
• Major bleeding
• Renal failure
• Arrhythmias [AV blocks, AFib]
• Aortic Regurgitation/Paravalvular leak
• Infections like Endocarditis