Sandbox/AIRSG

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

Aortic Regurgitation Resident Survival Guide Microchapters
Overview
Causes
FIRE
Complete Acute Chronic
Treatment
Do's
Don'ts

Overview

Aortic regurgitation (AR) refers to the retrograde or backward flow of blood from the aorta into the left ventricle during diastole. The presentation depends on the response and adaptability of the left ventricle to the increased diastolic volume, in chronic AR the left ventricle has adapted by dilatation of its walls. However, in acute AR, a rapid increase in the diastolic volume is not tolerated by a normal size ventricle and this could lead to cardiogenic shock. The most common causes of acute aortic regurgitation are aortic dissection and infective endocarditis and the preferred treatment in both cases surgical intervention. The most common cause of chronic AR is bicuspid aortic valve and the treatment will depend on the stage of the disease. Acute AR is a life-threatening condition and must be recognized and treated promptly.

Causes

Life Threatening Causes

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

• Aortic dissection
• Infective endocarditis

Common Causes

• Bicuspid aortic valve
• Senile or degenerative calcific aortic valve disease
• Hypertension
• Idiopathic dilatation of the aorta
• Myxomatous degeneration
• Rheumatic fever

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.

Boxes in salmon signify that an urgent management is needed.

Identify cardinal findings that increase the pretest probability of acute aortic regurgitation ❑ ❑ ❑

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

Diagnosis

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

Abbreviations: BP: blood pressure; CXR: chest X-ray; ECG: electrocardiogram; LV: left ventricle

Acute Aortic Regurgitation

Characterize the symptoms: ❑ Sudden and severe dyspnea ❑ Palpitations Symptoms of aortic dissection ❑ Chest pain ❑ Sudden, intense ❑ Tearing, sharp ❑ Interscapular ❑ Syncope Symptoms of infective endocarditis ❑ Fever

Inquire about past medical history: ❑ Cardiac disease: ❑ Hypertension ❑ Bicuspid aortic valve ❑ Rheumatic fever ❑ Marfan syndrome ❑ Connective tissue disorder

Examine the patient: Vitals ❑ Heart rate: ❑ Tachycardia ❑ Blood pressure: ❑ Systolic BP differential > 20 mmHg Cardiovascular examination ❑ Pulses ❑ Weak ❑ Cardiac auscultation ❑ Murmur ❑ Low pitched early diastolic murmur (may be absent) ❑ Heart sounds ❑ Decreased or absent S1 ❑ Increased P2 (suggestive of pulmonary hypertension) ❑ S3 may be present

Order imaging studies: ❑ Chest X-ray ❑ Increase cardiac silhouette (suggestive of aortic dissection) ❑ Widened mediastinum (suggestive of aortic root dilation) ❑ Pulmonary congestion (suggestive of HF) ❑ ECG ❑ Nonspecific changes of ST and T wave (due to LV enlargement) ❑ Right coronary artery ischemic changes (suggestive of aortic dissection) ❑ 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 the results from TTE

Chronic Aortic Regurgitation

Characterize the symptoms: ❑ Dyspnea on exertion ❑ Orthopnea ❑ Paroxysmal nocturnal dyspnea ❑ Palpitations ❑ Chest pain

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

Examine the patient: Vitals ❑ Heart rate: ❑ Tachycardia (suggestive of reduced stroke volume) ❑ Blood pressure: ❑ Wide pulse pressure (≥ 60 mmHg) Cardiovascular examination ❑ Pulses ❑ Corrigan's pulse: a rapid upstroke and collapse of the carotid artery pulse ❑ Cardiac auscultation ❑ Murmur ❑ Early diastolic decrescendo murmur ❑ Best heard at the upper left sternal border ❑ Murmur increases with sitting forward, expiration and handgrip ❑ Austin Flint murmur: a soft mid-diastolic rumble, best heard at the cardiac apex ❑ Heart sounds ❑ S3 may be present (suggestive of left ventricular dysfunction) ❑ Search for other signs suggestive of aortic regurgitation ❑ Traube's sign: systolic and diastolic murmurs described as 'pistol shots' heard over the femoral artery when it is gradually compressed ❑ Müller's sign: systolic pulsations of uvula ❑ de Musset's sign: head bobbing with each heart beat ❑ Hill's sign: ≥ 20 mmHg difference in popliteal and brachial systolic cuff pressures (suggestive of chronic severe AR) ❑ Quincke's sign: pulsation of the capillary bed in the nail Respiratory examination ❑ Rales (seen when congestive heart failure has developed)

Order imaging studies: ❑ Chest X-ray ❑ Increase cardiac silhouette (suggestive of aortic dissection) ❑ Widened mediastinum (suggestive of aortic root dilation) ❑ Pulmonary congestion (suggestive of HF) ❑ ECG ❑ Nonspecific changes of ST and T wave (due to LV enlargement) ❑ 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 the results from TTE

Risk of AI (Stage A) ❑ No regurgitation

Mild (Stage B) ❑ Vena contracta <0.3 cm ❑ Jet/LVOT <25% ❑ Regurgitant volume <30 mL/beat ❑ Regurgitant fraction <30% ❑ Effective regurgitant orifice <0.10 cm²

Moderate (Stage B) ❑ Vena contracta 0.3-0.6 cm ❑ Jet/LVOT 25-64% ❑ Regurgitant volume 30-59 mL/beat ❑ Regurgitant fraction 30-49% ❑ Effective regurgitant orifice 0.10-0.29 cm²

Severe ❑ Vena contracta >0.6 cm ❑ Jet/LVOT ≥ 65% ❑ Regurgitant volume ≥60 mL/beat ❑ Regurgitant fraction ≥50% ❑ Effective regurgitant orifice ≥ 0.30 cm² ❑ Holodiastolic flow reversal in the proximal abdominal aorta

Asymptomatic Stage C1 ❑ Normal LVEF ❑ Mild to moderate dilatation Stage C2 ❑ LV systolic dysfunction ❑ Decreased LVEF or severe LV dilatation

Symptomatic (Stage D) ❑ Normal or decreased LV systolic function ❑ Moderate to severe LV dilatation

Treatment

Treatment of Acute Aortic Regurgitation

Shown below is an algorithm for the treatment of acute aortic regurgitation according to the 2014 AHA/ACC Guidelines for the Management of Valvular Heart Disease.

Treatment ❑ The use of nitroprusside and inotropic agents (such as: dopamine and dobutamine) help reduce the LV end-diastolic pressure before surgery ❑ Avoid the use of beta blockers because may block compensating tachycardia

Infective endocarditis

Aortic dissection

Mild or moderate

Severe

Urgent surgical intervention ❑ Aortic valve replacement ❑ Intra-aortic balloon counterpulsation is contraindicated

Antibiotic treatment A complete list of pathogen specific antibiotics regimens with appropriate dosages and duration of treatment is available here

Chronic Aortic Regurgitation

Shown below is an algorithm summarizing the treatment approach to chronic aortic regurgitation according to the 2014 AHA/ACC Guidelines on the Management of Valvular Heart Disease.

Interpret results from TTE

No regurgitation (Stage A)

Progressive regurgitation (Stage B) Mild ❑ Vena contracta <0.3 cm ❑ Jet/LVOT <25% ❑ Regurgitant volume <30 mL/beat ❑ Regurgitant fraction <30% ❑ Effective regurgitant orifice <0.10 cm² Moderate ❑ Vena contracta 0.3-0.6 cm ❑ Jet/LVOT 25-64% ❑ Regurgitant volume 30-59 mL/beat ❑ Regurgitant fraction 30-49% ❑ Effective regurgitant orifice 0.10-0.29 cm²

Severe regurgitation ❑ Vena contracta >0.6 cm ❑ Jet/LVOT ≥ 65% ❑ Regurgitant volume ≥60 mL/beat ❑ Regurgitant fraction ≥50% ❑ Effective regurgitant orifice ≥ 0.30 cm² ❑ Holodiastolic flow reversal in the proximal abdominal aorta

Asymptomatic patients ❑ Normal valve ❑ Bicuspid valve ❑ Sclerotic valve

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

Asymptomatic (Stage C)

Symptomatic (Stage D)

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

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

Stage C1 ❑ Normal LVEF ❑ Mild to moderate dilatation

Stage C2 ❑ LV systolic dysfunction ❑ Decreased LVEF ❑ Severe LV dilatation

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

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

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

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)

Do's

❑

Don'ts

❑ Do not use beta blockers in AI of causes other than AD as it will block the compensation tachycardia. ❑ Do not use intra-aortic baloon counterpulsation in severe acute AI as it will increase the aortic diastolic pressure and the regurgitant volume.

References

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