Sandbox/AIRSG

# 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

# 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 color signify that an urgent management is needed.
Abbreviations: ECG: electrocardiogram; TTE: transthoracic echocardiography; TEE: transesophageal echocardiography; S1: first heart sound; P2: second heart sound, pulmonary component; S3: third heart sound

# 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; MI: myocardial infarction; TTE: transthoracic echocardiography; TEE: transesophageal echocardiography; TAVR: transcatheter aortic valve replacement; S1: first heart sound; S2: second heart sound; S3: third heart sound;

## Acute Aortic Regurgitation

## Chronic Aortic Regurgitation

# 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 and the 2010 ACCF/AHA Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease

## Treatment of 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.
Abbreviations: TTE: transthoracic echocardiography; AVR: aortic valve replacement; CCB: calcium channel blocker; ACE: angiotensin converting enzyme; ARB: angiotensin receptor blocker

## Type of Valve and Discharge Anticoagulation Therapy
Abbreviations: AVR: Aortic valve replacement; INR: International normalized ratio; TAVR Tansthoracic aortic valve replacement

# Do's
 Perform a cardiac MRI in patients with moderate or severe AR with an inconclusive TTE to assess LV systolic function, systolic and diastolic
volumes, and measurement of AR severity. (Class I; Level of Evidence: B) 
 Exercise stress test could be useful to assess symptomatic status and functional capacity of patents with severe aortic regurgitation 

# Don'ts
 Do not use beta blockers in aortic regurgitation  that is not caused by aortic dissection as it will block the compensatory tachycardia. 
 Do not use intra-aortic baloon counterpulsation in severe acute AI as it will increase the aortic diastolic pressure and the regurgitant volume.
 Do not give antibiotics to patients with known VHD before blood cultures are obtained for unexplained fever.  (Class III; Level of Evidence: C) 
 Do not give ACE inhibitors to pregnant patients with aortic regurgitation. (Class III; Level of Evidence: B)