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 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). Symptoms of aortic stenosis are evident when the stenosis is ≤ 1.0 cm². The symptoms are caused by a decrease in the stroke volume and the subsequent decreased perfusion to peripheral tissues. The most common etiology is calcific aortic valve disease. The management of aortic stenosis depends on whether the patient is symptomatic or asymptomatic. Aortic valve replacement is the treatment of choice for symptomatic patients.

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. The algorithm below is based on the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease .
Abbreviations: STEMI: ST elevation myocardial infarction; AVR: aortic valve replacement
Boxes in red signify that an urgent management is needed.

Identify cardinal findings that increase the pretest probability of acute aortic stenosis ❑ Systolic ejection murmur ❑ Best heard at the upper right sternal border ❑ Bilateral radiation to the carotid arteries ❑ Pulsus parvus et tardus ❑ Severe dyspnea

Does the patient have any of the following findings that require urgent management? ❑ Tachycardia ❑ Hypotension ❑ Loss of consciousness ❑ Tachypnea

Yes

No

❑ Assess airway, breathing, and circulation ❑ Administer oxygen if necessary ❑ Monitor vitals continuously

Continue with the diagnostic approach below

❑ Treat the underling cause of the decompensation ❑ Do not give nitrates (could cause severe hypotension)

Acute heart failure Suspect if: ❑ Severe dyspnea ❑ Signs of volume overload ❑ Manage volume overload with diuretics

Atrial fibrillation Suspect if: ❑ Palpitations ❑ Order EKG immediately ❑ Control rhythm

Syncope Suspect if: ❑ Loss of consciousness of: ❑ Short duration ❑ Rapid onset ❑ Complete spontaneous recovery ❑ Determine the etiology of the syncope ❑ Cardiogenic ❑ Reflex ❑ Orthostatic hypotension

Acute coronary syndrome Suspect if: ❑ Severe chest pain ❑ Order an EKG immediately

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 Click here for NSTEMI resident survival guide

Patients with severe aortic stenosis and failure to improve with medical therapy: ❑ Perform urgent AVR

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 ❑ Exertional dizziness ❑ 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 ❑ Rhythm and rate are normal 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) ❑ Systolic 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 {{#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 imaging and adjuvant studies: ❑ 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 ❑ TTE (most important evaluation test) (Class I; Level of Evidence: B) Assess the following: ❑ Valve morphology ❑ Pressure gradient ❑ Aortic valve area ❑ Ejection fraction ❑ LV wall thickness and motility

Interpret results from TTE

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

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

Interpret results from TTE

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 gradient (ΔP ≥ 40 mmHg) (Stage D1)

Low gradient (ΔP ≤ 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 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

Patient scheduled for AVR

High risk

Low to moderate risk

❑ A multidisciplinary group 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)

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

Determine: ❑ Age ❑ Contraindications for anticoagulation ❑ Major bleeding diathesis or coagulopathy ❑ Uncontrolled severe hypertension (systolic BP >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, LV dysfunction, and previous thromboembolism.

Do's

❑ Give ACE inhibitors to control hypertension in patients with asymptomatic aortic stenosis.
❑ Perform a TTE after aortic valve replacement for evaluation of 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 AS 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 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 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 TAVR in patients in whom existing comorbidities would preclude the expected benefit from correction of AS (Class III; Level of Evidence: B)
❑ Do not administer vasodilators to patients with severe AS as they may cause severe hypotension.
❑ Do not administer endocarditis prophylaxis in patients with AS.

References

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