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
FIRE
Diagnosis
Treatment General Approach Choice of Intervention Type of Valve and Discharge Anticoagulation Therapy
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). The symptoms are caused by a decrease in the stroke volume which reduces blood flow to peripheral tissues. The most common etiology of arotic stenosis is calcific aortic valve disease. The management of aortic stenosis depends on whether the patient is symptomatic or asymptomatic, the area of the valve, and the hemodynamic response to exercise.

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

Click here for the complete list of causes.

FIRE: Focused Initial Rapid Evaluation

A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention.
Boxes in the red signify that an urgent management is needed.

Abbreviations: AVR: Aortic valve replacement; CK-MB: Creatine kinase myocardial type; ECG: Electrocardiogram; NSTEMI: Non ST elevation myocardial infarction; STEMI: ST elevation myocardial infarction; TTE: Transthoracic echocardiography

Identify cardinal findings that increase the pretest probability of aortic stenosis ❑ Systolic ejection murmur ❑ Crescendo-decrescendo ❑ Associated with an ejection click ❑ Best heard at the upper right sternal border ❑ Bilateral radiation to the carotid arteries ❑ Increases with squatting and expiration ❑ Decreases with valsalva maneuver ❑ Pulsus parvus et tardus ❑ Narrow pulse pressure

Does the patient have any of the following findings of decompensated aortic stenosis that require urgent management? ❑ Tachycardia ❑ Hypotension ❑ Severe dyspnea ❑ Loss of consciousness ❑ Chest pain

Yes

No

What is the complication of aortic stenosis that is causing decompensation?

Proceed to the complete diagnostic approach below

Acute heart failure ❑ Suspect in case of: ❑ Severe dyspnea ❑ Signs of volume overload

Atrial fibrillation ❑ Suspect in case of palpitations ❑ Order an ECG immediately looking for ❑ Irregularly irregular rhythm, and ❑ Absent P waves

Syncope ❑ Suspect in case of loss of consciousness of: ❑ Short duration ❑ Rapid onset ❑ Complete spontaneous recovery

Acute coronary syndrome ❑ Suspect in case of severe chest pain ❑ Order an ECG immediately ❑ Order troponin and CK-MB

Click here for acute heart failure resident survival guide

Click here for atrial fibrillation resident survival guide

Click here for syncope resident survival guide

Click here for STEMI resident survival guide, or Click here for NSTEMI resident survival guide

❑ Treat the complications of aortic stenosis that lead to decompensation ❑ Order a TTE to evaluate the severity of the aortic stenosis ❑ Do not give nitrates (could cause severe hypotension) ❑ Monitor vital signs continuously

Does the patient improve with medical therapy?

No

Yes

❑ Proceed with urgent AVR

Continue with the complete diagnostic approach below

Complete Diagnostic Approach

A complete diagnostic approach should be carried out after a focused initial rapid evaluation is conducted and following initiation of any urgent intervention.

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

Characterize the symptoms: ❑ Asymptomatic ❑ Dyspnea on exertion ❑ Dizziness on exertion ❑ Syncope ❑ Chest pain ❑ Palpitations

Inquire about past medical history: ❑ Cardiovascular disease ❑ Hypertension ❑ Bicuspid aortic valve ❑ Rheumatic fever ❑ Pulmonary disease

Examine the patient: Vitals ❑ Heart rate ❑ Normal rhythm and rate (in most cases) ❑ Irregularly irregular rhythm (suggestive of AF in late stage disease) ❑ Blood pressure ❑ Narrow pulse pressure (<25 mmHg) ❑ Mild hypertension in moderate stenosis ❑ Hypotension in severe stenosis ❑ Respiratory rate ❑ Normal in most cases ❑ Tachypnea (suggestive of HF) Cardiovascular examination ❑ Cardiac palpation ❑ Apical impulse (suggestive of LVH) ❑ Palpable thrill ❑ Pulses ❑ Pulsus parvus et tardus ❑ Pulsus bisferiens (suggestive of mixed aortic stenosis and regurgitation) ❑ Cardiac auscultation ❑ Murmur ❑ 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 and expiration ❑ Murmur decreases with valsalva maneuver Click on the video below to listen to an aortic stenosis murmur. {{#ev:youtube|MJg257pyt4I|200}} ❑ Heart sounds ❑ Normal S1 ❑ Paradoxical splitting of S2 (in severe disease) ❑ S3 (suggestive of LVH) Respiratory examination ❑ Rales (suggestive of congestive heart failure) Extremities ❑ Peripheral edema (suggestive of congestive heart failure)

Order tests: ❑ TTE (most important evaluation test) (Class I; Level of Evidence: B) Assess the following: ❑ Valve morphology ❑ Pressure gradient ❑ Aortic valve area ❑ Ejection fraction ❑ Left ventricle wall thickness and motility ❑ ECG (shows non-specific findings): ❑ LVH ❑ Left atrium enlargement ❑ LBBB ❑ AF (in late disease) ❑ Chest X-ray: ❑ Cardiomegaly ❑ Valve calcification ❑ Dilatation of ascending aorta ❑ Pulmonary congestion

Classify aortic stenosis based on the following findings on TTE: ❑ Valve area ❑ Transvalvular pressure gradient

No stenosis ❑ Valve area 2.5-3.5 cm² ❑ No pressure gradient across the valve

Mild stenosis ❑ Valve area 1.5-2.5 cm² ❑ Pressure gradient ≤ 25 mmHg

Moderate stenosis ❑ Valve area 1.0-1.5 cm² ❑ Pressure gradient 25-40 mmHg

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

Treatment

General Approach

Shown below is an algorithm for the treatment of aortic stenosis according to the stage of the disease based on the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease

Abbreviations: AVR: Aortic valve replacement; LVEF: Left ventricular ejection fraction; TTE: Transthoracic echocardiography

Classify aortic stenosis based on the following findings on TTE: ❑ Valve area ❑ Transvalvular pressure gradient

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

Asymptomatic patients ❑ Normal valve ❑ Bicuspid valve ❑ Sclerotic valve

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

Asymptomatic (Stage C) ❑ Pressure gradient ≥ 40 mmHg

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 pressure gradient (≥ 40 mmHg) (Stage D1)

Low pressure gradient (≤ 40 mmHg) ❑ LVEF < 50% (Stage D2) ❑ Normal LVEF (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) Click here for low flow low gradient aortic stenosis resident survival guide

If aortic velocity ≥ 5 m/s or there is a 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 aortic valve replacement among patients with aortic stenosis based on the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease
Abbreviations: AVR: Aortic valve replacement; TAVR Tansthoracic aortic valve replacement

What is the surgical and interventional risk of the patient? (The risk score is shown below)

High risk

Low to moderate risk

❑ A multidisciplinary group should decide intervention (surgical AVR or TAVR) (Class I; Level of Evidence: C) ❑ Consider TAVR (Class IIa; Level of Evidence: B)

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

Evaluation of Surgical and Interventional Cardiac Risk

Shown below is a table to assess the surgical and interventional risk which combines the STS risk estimate, frailty, major organ system dysfunction and procedure-specific impediments.

	Society of Thoracic Surgeons Predicted Risk of Mortality Score	Frailty*	Major organ system compromised without postoperative improvement	Specific procedural impediment **
Low risk	<4% AND	None AND	None AND	None
Intermediate risk	4% to 8% OR	1 index OR	1 organ system OR	Possible
High risk	>8% OR	≥2 indices (moderate to severe) OR	No more than 2 organ systems OR	Possible
Prohibitive risk	>50% of predicted risk of death or major morbidity at 1 year OR	>50% of predicted risk of death or major morbidity at 1 year OR	≥3 organ systems	Severe

*Seven frailty indices: Katz Activites of Daily Living (self-sufficient in feeding, bathing, dressing, transferring, toileting and urinary continence) and self-sufficient in deambulation (no walking aid or assist required or 5-meter walk in <6 s).
**Examples of specific procedural impediment: tracheostomy present, heavily calcified ascending aorta, chest malformation, arterial coronary graft adherent to posterior chest wall or radiation damage.

Type of Valve and Discharge Anticoagulation Therapy

Abbreviations: AVR: Aortic valve replacement; INR: International normalized ratio; TAVR Tansthoracic aortic valve replacement

Determine: ❑ Age ❑ Contraindications for anticoagulation ❑ Major bleeding diathesis or coagulopathy ❑ Uncontrolled severe hypertension (systolic blood pressure >200 mmHg) ❑ Recent head trauma ❑ Platelet count < 100 000 ❑ Pregnancy ❑ Hypersensitivity to warfarin ❑ Hemorrhagic stroke

❑ Patients ≤ 60 years old (Class IIa; Level of Evidence: B), AND ❑ No contraindication for anticoagulation

❑ Patients 60 - 70 years old ❑ No contraindication for anticoagulation

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

Mechanical Prosthesis Avoid the use of direct thrombin inhibitors or anti-Xa agents in patients with mechanical prosthesis (Class III; Level of Evidence: B)

Either a bioprosthesic or mechanical valve is reasonable (Class IIa; Level of Evidence: B).

Bioprosthesis

Patient with risk factors†

Patient without risk factors†

Surgical AVR

TAVR

Administer for long term: ❑ Warfarin to achieve INR of 3.0 ❑ Aspirin 75-100 mg/d

Administer for long term: ❑ Warfarin to achieve INR of 2.5 ❑ Aspirin 75-100 mg/d

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

Administer for 6 months: ❑ Clopidogrel 75 mg/d ❑ Aspirin 75-100 mg/d

†Risk factors for thromboembolism include atrial fibrillation, hypercoagulable conditions, left ventricle dysfunction, and previous thromboembolism.

Do's

• Administer ACE inhibitors to control hypertension among patients with asymptomatic aortic stenosis.

• Perform a transthoracic echocardiography (TTE) after aortic valve replacement fto evaluate the valve hemodynamics (Class I; Level of Evidence: B).

• Perform a TTE when clinical symptoms or signs suggest prosthetic valve dysfunction (Class I; Level of Evidence: C).

• Consider exercise testing in asymptomatic patients with aortic stenosis to elicit exercise-induced symptoms and abnormal blood pressure responses (Class IIb; Level of Evidence: B).

• Consider dobutamine stress echocardiography to evaluate patients with low-flow/low-gradient AS and LV dysfunction (Stage D3) (Class IIa; Level of Evidence: B).

• Consider aortic balloon valvotomy as a bridge to surgery in hemodynamically unstable adult patients with aortic stenosis among whom aortic valve replacement cannot be performed because of a high surgical risk or due to the presence 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 administer statins to prevent hemodynamic progression in patients with mild to moderate calcific aortic valve disease (Class III; Level of Evidence: A).

• Do not perform a transcatheter aortic valve implantation (TAVR) among patients in whom existing comorbidities would preclude the expected benefit from the correction of aortic stenosis (Class III; Level of Evidence: B).

• Do not administer vasodilators to patients with severe aortic stenosis because vasodilators may cause severe hypotension which can precipitate or exacerbate the symptoms of aortic stenosis.

• Do not administer endocarditis prophylaxis among patients with aortic stenosis.

References

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