Aortic stenosis resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alejandro Lemor, M.D. [2]

Aortic Stenosis Resident Survival Guide Microchapters
Overview
Causes
Diagnosis
Treatment
Do's
Don'ts

Overview

Aortic stenosis is the progressive narrowing of the diameter of the aortic valve (normal valve area is 3 - 4 cm²) and symptoms are caused by a decrease in stroke volume that leads to decrease perfusion to peripheral tissues, however, symptoms normally appear when the stenosis is ≤ 1.0 cm². The most common etiology of aortic stenosis is calcific aortic valve disease. The management will depend if the patient is symptomatic or asymptomatic. Surgical intervention is the treatment of choice for patients with symptomatic aortic stenosis.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Infective Endocarditis

Common Causes

• Calcific aortic valve disease
• Rheumatic fever
• Congenital bicuspid aortic valve
• Endocarditis

Diagnosis

Shown below is an algorithm summarizing the diagnosis approach to aortic stenosis based on the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary

Abbreviations: LVH: Left ventricle hypertrophy; CXR: Chest x-ray; ECG: Electrocardiogram; LBBB: Left bundle branch block; AF: Atrial fibrillation; AVR: Aortic valve replacement; VHD: Valve heart disease; TAVR: Transcatheter aortic valve replacement

Characterize the symptoms: ❑ Most patients are asymptomatic ❑ Dyspnea on exertion ❑ Exertional dizziness ❑ Exertional angina ❑ Syncope ❑ Chest pain ❑ Palpitations

Inquire about past medical history: ❑ Previously healthy ❑ Cardiac disease: ❑ Hypertension ❑ Bicuspid aortic valve ❑ Rheumatic fever ❑ Pulmonary disease

Examine the patient: ❑ Heart rate ❑ Pulses ❑ Pulsus parvus et tardus ❑ Cardiac palpation ❑ Apical impulse (due to LVH) ❑ Systolic thrill ❑ Cardiac auscultation ❑ Crescendo-decrescendo systolic ejection murmur with ejection click ❑ Best heard at the upper right sternal border ❑ Bilateral radiation to the carotid arteries ❑ Murmur increases with: squatting, expiration ❑ Murmur decreases with valsalva maneuver {{#ev:youtube|MJg257pyt4I|200}} ❑ Pulmonary auscultation: search for rales (seen when congestive heart failure has developed)

Order imaging and adjuvant studies: ❑ Order an echocardiography, assess: ❑ Valve morphology ❑ Pressure gradient ❑ Aortic valve area ❑ Ejection fraction ❑ LV wall thickness and motility ❑ Order a CXR, look for: ❑ Cardiomegaly ❑ Valve calcification ❑ Dilatation of ascending aorta ❑ Pulmonary congestion ❑ Order a ECG, look for: ❑ LVH ❑ Left atrium enlargement ❑ LBBB ❑ AF (in late disease)

Interpret results from echo

No stenosis (Stage A) ❑ Valve area 2.5-3.5 cm² ❑ No pressure gradient

Mild to moderate stenosis (Stage B) Mild: ❑ Valve area 1.5-2.5 cm² ❑ Pressure gradient ≤ 25 mmHg Moderate: ❑ Valve area 1.0-1.5 cm² ❑ Pressure gradient 25-40 mmHg

Severe stenosis ❑ Valve area ≤ 1.0 cm² ❑ Pressure gradient ≥ 40 mmHg

❑ Normal valve ❑ Bicuspid valve ❑ Sclerotic valve

Perform a periodic echocardiogram (Class I; Level of Evidence: B) ❑ Every 3 -5 years for mild stenosis ❑ Every 1 - 2 years for moderate stenosis

Patient asymptomatic (Stage C)

Patient symptomatic (Stage D)

❑ Control hypertension (Class I; Level of Evidence: B)

If patient undergoes another cardiac surgery: ❑ Schedule for AVR (Class IIa; Level of Evidence: C)

Normal LVEF (Stage C1)

LVEF < 50% (Stage C2)

High gradient (ΔP ≥ 40 mmHg) (Stage D1)

Low gradient (ΔP ≤ 40 mmHg) ❑ Normal LVEF (Stage D2) ❑ LVEF < 50% (Stage D3)

Perform a periodic echocardiogram every 6 - 12 months (Class I; Level of Evidence: B)

Schedule for AVR (Class I; Level of Evidence: A)

Schedule for AVR (Class IIa; Level of Evidence: B-C)

If aortic velocity ≥ 5 m/s or decrease in exercise tolerance: ❑ Schedule for AVR (Class IIa; Level of Evidence: B)

Choice of Intervention

Shown below is an algorithm summarizing the choice of the intervention to aortic stenosis based on the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary
STS: Society of Thoracic Surgeons

Patient scheduled for AVR

High risk ❑ STS Score > 10 ❑ EuroScore > 20

Low to moderate risk ❑ STS Score < 10 ❑ EuroScore < 20

❑ A multidisciplinary group of physicians with expertise in VHD, cardiac imaging, interventional cardiology, cardiac anesthesia, and cardiac surgery should decide intervention (Surgical AVR or TAVR) (Class I; Level of Evidence: C) ❑ Schedule for TAVR (Class IIa; Level of Evidence: B)

❑ Schedule for surgical AVR (Class I; Level of Evidence: A)

Type of Valve and Discharge Anticoagulation Therapy

❑ Determine the age of the patient ❑ Check for contraindications for anticoagulation

❑ Patients ≤ 70 years old (Class IIa; Level of Evidence: B), and ❑ No contraindication for anticoagulation

❑ Patients ≥ 70 years old (Class IIa; Level of Evidence: B), or ❑ Patients with anticoagulant therapy contraindications (Class I; Level of Evidence: C)

Mechanical Prosthesis

Bioprosthesis

Patient with risk factors

Patient without risk factors

AVR

TAVR

❑ Give warfarin to achieve INR of 3.0 ❑ Give aspirin 75-100 mg/d ❑ Both long term

❑ Give warfarin to achieve INR of 2.5 ❑ Give aspirin 75-100 mg/d ❑ Both long term

❑ Give warfarin to achieve INR of 2.5 for 3 months ❑ Then give aspirin 75-100 mg/d long term

❑ Give clopidogrel 75 mg/d ❑ Give aspirin 75-100 mg/d ❑ Both for 6 months

❑ Either a bioprosthetic or mechanical valve is reasonable in patients between 60 and 70 years of age. (Class IIa; Level of Evidence: B).

Do's

❑ Give ACE inhibitors to control hypertension in patients with asymptomatic aortic stenosis.
❑ Exercise testing in asymptomatic patients with AS may be considered to elicit exercise-induced symptoms and abnormal blood pressure responses (Class IIb; Level of Evidence: B).
❑ Dobutamine stress echocardiography is reasonable to evaluate patients with low-flow/low-gradient AS and LV dysfunction (Stage D3) (Class IIa; Level of Evidence: B)
❑ Aortic balloon valvotomy might be reasonable as a bridge to surgery in hemodynamically unstable adult patients with AS who are at high risk for AVR or cannot be performed because of serious comorbid conditions.(Class IIb; Level of Evidence: C).

Don'ts

❑ Do not perform a stress test in a symptomatic patient with stage D aortic stenosis (Class III; Level of Evidence: B).
❑ Do not give statins to prevent hemodynamic progression in patients with mild to moderate calcific aortic valve disease (Class III; Level of Evidence: A).
❑ TAVR is not recommended in patients in whom existing comorbidities would preclude the expected benefit from correction of AS (Class III; Level of Evidence: B)
❑ Do not give vasodilators to patients with severe AS as they may cause severe hypotension.
❑ Endocarditis prophylaxis is not indicated in patients with AR.

References

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