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]; Rim Halaby, M.D. [3]

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 aortic stenosis is calcific aortic valve disease. The management of aortic stenosis depends on the stage of the disease which is determined by whether the patient is symptomatic or asymptomatic, the area of the valve, and the hemodynamic consequences of the stenosis.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Aortic stenosis is a progressive disease and does not have a life threatening cause.

Common Causes

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

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 (a weak and slow upstroke of the carotid waveform is an excellent indicator of aortic stenosis severity) ❑ Narrow pulse pressure

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

Yes

No

Proceed to the complete diagnostic approach below

The patient has a condition that exacerbates AS

The patient has a decompensated AS causing complications

Atrial fibrillation ❑ Suspect if there are palpitations ❑ Order an ECG immediately looking for ❑ Irregularly irregular rhythm, and ❑ Absent P waves

Acute coronary syndrome ❑ Suspect if there is severe chest pain ❑ Order an ECG immediately ❑ Order troponin and CK-MB

Syncope ❑ Suspect if there is loss of consciousness of: ❑ Short duration ❑ Rapid onset ❑ Complete spontaneous recovery

Acute heart failure ❑ Suspect if there are: ❑ Severe dyspnea ❑ Signs of volume overload

Click here for atrial fibrillation resident survival guide

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

Click here for syncope resident survival guide

Click here for acute heart failure 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: AS: Aortic stenosis; 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: ❑ Chest pain, angina-type pain (Left untreated, the average survival is 5 years after the onset of angina in the patient with AS) ❑ The pain is crushing, squeezing, pressure or tightness in nature ❑ The pain increases with exercise, relieved with rest ❑ Pain under the chest bone, it may move to other areas ❑ Syncope (Left untreated, the average survival is 3 years after the onset of syncope in the patient with AS) ❑ Symptoms suggestive of congestive heart failure (Left untreated, the average survival is 1 years after the onset of heart failure in the patient with AS) ❑ Dyspnea on exertion ❑ Fatigue ❑ Orthopnea ❑ Paroxysmal nocturnal dyspnea ❑ Pulmonary edema ❑ Pulmonary hypertension that can lead to: ❑ Right ventricular failure ❑ Hepatomegaly ❑ Atrial fibrillation ❑ Peripheral edema ❑ Tricuspid regurgitation ❑ 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 (cm²) ❑ Transvalvular pressure gradient (mmHg) ❑ Aortic Vmax (m/s)

No stenosis ❑ Valve area 2.5-3.5 cm² ❑ No pressure gradient across the valve ❑ Aortic Vmax <2 m/s

Mild stenosis ❑ Valve area 1.5-2.5 cm² ❑ Pressure gradient ≤ 25 mmHg ❑ Aortic Vmax 2.0-2.9 m/s

Moderate stenosis ❑ Valve area 1.0-1.5 cm² ❑ Pressure gradient 25-40 mmHg ❑ Aortic Vmax 3.0-3.9 m/s

Severe stenosis ❑ Valve area ≤ 1.0 cm² ❑ Pressure gradient ≥ 40 mmHg (except for stages D2 and D3, low flow low gradient) ❑ Aortic Vmax ≥ 4 m/s

Treatment

Indications for Aortic Valve Replacement

Shown below is an algorithm depicting the indications for aortic valve replacement (AVR). If the patient does not meet any of the decision pathways in the algorithm, regular monitoring is recommended and AVR is not indicated.

Abbreviations: AVR: Aortic valve replacement; LVEF: Left ventricular ejection fraction; ΔP_mean: mean pressure gradient; V_max: maximum velocity

Abnormal aortic valve AND Reduction in systolic opening

Severe aortic stenosis: Vmax≥4m/s AND ΔPmean≥40 mmHg

Vmax3-3.9 m/s AND ΔPmean20-39 mmHg

Is the patient symptomatic?

Is the patient symptomatic?

Yes (Stage D1)

No (Stage C)

Yes

No (Stage B)

LVEF <50% (Stage C2)

Is LVEF <50%?

The patient is undergoing another cardiac surgery

The patient is undergoing another cardiac surgery

Yes

No

Vmax≥5m/s AND ΔPmean≥60 mmHg (Very severe stage C1) AND Low surgical risk

Dobutamine stress echocardiography: Aortic valve area ≤1 cm2 AND Vmax≥4 ms (Stage D2)

Aortic valve area ≤1 cm2 AND LVEF ≥50% (Stage D3)

Abnormal exercise treadmill test

The symptoms are likely the result of the aortic stenosis

ΔVmax>0.3 m/s/y AND Low surgical risk

AVR (Class I)

AVR (Class IIa)

AVR (Class IIb)

AVR (Class IIa)

AVR (Class IIa)

AVR (Class IIa)

Choice of Intervention

Shown below is a table 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

Choice of AVR	Indications
Surgical AVR	- Low or intermediate surgical risk (Class I; Level of Evidence: A)
Tansthoracic aortic valve replacement (TAVR)	- Prohibitive surgical risk and a predicted post-TAVR survival >12 month (Class I; Level of Evidence: B) - High surgical risk (Class IIa; Level of Evidence: B)

Evaluation of Surgical and Interventional Cardiac Risk

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

	STC Predicted Risk of Mortality Score	Frailty*	Major organ system compromised without postoperative improvement	Specific procedural impediment**
Low risk (Must meet ALL criteria in this row)	<4%	None	None	None
Intermediate risk (Must meet ANY criteria in this row)	4% to 8%	1 index (mild)	1 organ system	Possible
High risk (Must meet ANY criteria in this row)	>8%	≥2 indices (moderate to severe)	No more than 2 organ systems	Possible
Prohibitive risk (Must meet ANY criteria in this row)	>50% of predicted risk of death or major morbidity at 1 year	>50% of predicted risk of death or major morbidity at 1 year	≥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 AND ❑ No contraindication for anticoagulation (Class IIa; Level of Evidence: B)

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

❑ Patients ≥ 70 years old (Class IIa; Level of Evidence: B) OR ❑ Patients at any age AND contraindications for anticoagulation therapy (Class I; Level of Evidence: C)

Bioprosthesic OR Mechanical prosthesis (Class IIa; Level of Evidence: B)

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

Bioprosthesis

Does the patient have risk factors for thromboembolism†?

Surgical AVR OR TAVR

Yes

No

Surgical AVR

TAVR

Administer for long term: ❑ Warfarin to achieve INR of 3.0 (Class I; Level of Evidence: B) AND ❑ Aspirin 75-100 mg/d (Class I; Level of Evidence: A)

Administer for long term: ❑ Warfarin to achieve INR of 2.5 (Class I; Level of Evidence: B) AND ❑ Aspirin 75-100 mg/d (Class I; Level of Evidence: A)

Administer ❑ Warfarin to achieve INR of 2.5 for 3 months (Class IIb; Level of Evidence: B) AND ❑ Aspirin 75-100 mg/d long term (Class IIa; Level of Evidence: B)

Administer: ❑ Clopidogrel 75 mg/d (first 6 months) (Class IIb; Level of Evidence: C) AND ❑ Aspirin 75-100 mg/d (for life) (Class IIa; Level of Evidence: B)

†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 to 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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