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]
Synonyms and keywords: AS; critical AS; tight AS; aortic valve stenosis; calcific aortic stenosis; senile calcific aortic stenosis; degenerative calcific aortic stenosis

Aortic Stenosis Resident Survival Guide Microchapters
Overview
Causes
Diagnosis FIRE Complete Diagnostic Approach
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

Diagnosis

First Initial Rapid Evaluation of Suspected Aortic Stenosis

Shown below is an algorithm for the First Initial Rapid Evaluation (FIRE) of suspected aortic stenosis.

Identify cardinal signs and symptoms 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 ❑ Hypotension

Identify alarming signs and symptoms ❑ Tachycardia ❑ Hypotension ❑ Loss of consciousness ❑ Tachypnea

Unstable patient

Stable patient

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

Continue with the diagnostic approach

❑ 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

Angina 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 that not improve with medical therapy: ❑ Perform urgent AVR

Complete Diagnostic Approach to Aortic Stenosis

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

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: Valve heart disease

Characterize the symptoms: ❑ Most patients are asymptomatic ❑ Dyspnea on exertion ❑ Exertional dizziness ❑ Exertional angina ❑ 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 ❑ Arrhythmic (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 (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

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)

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

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

❑ 60 to 70 years of age

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

Mechanical Prosthesis

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

Bioprosthesis

Patient with risk factors

Patient without risk factors

Surgical 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

Avoid the use of direct thrombin inhibitors or anti-Xa agents in patients with mechanical prosthesis (Class III; 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 AS.

References

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