Aortic insufficiency (AI), also known as aortic regurgitation (AR), is a condition where the aortic valve fails to close completely during diastole, allowing blood to leak back from the aorta into the left ventricle. This backflow increases the volume load on the left ventricle, eventually leading to ventricular dilation, hypertrophy, and heart failure if untreated.
AI can develop acutely (e.g., due to aortic dissection, infective endocarditis) or chronically (e.g., due to congenital malformation, rheumatic heart disease). Acute AI is a medical emergency, while chronic AI may remain asymptomatic for years.
Pathophysiology
Normal function: The aortic valve prevents backflow of blood during ventricular diastole.
In AI: Valve leaflet damage, annular dilation, or aortic root disease compromises closure.
- Volume overload of the left ventricle.
- Increased stroke volume (bounding pulses).
- Progressive LV dilation and reduced ejection fraction over time.
Causes – CHEMISTS DAR Mnemonic
The mnemonic CHEMISTS DAR helps recall the key causes of AI:
| Letter | Cause | Explanation |
|---|---|---|
| C | Congenital aortic valve disease | Bicuspid valve, unicuspid valve, associated with genetic syndromes. |
| H | Hypertension | Chronic pressure load can dilate the aortic root and damage the valve. |
| E | Endocarditis | Infective destruction of leaflets causes acute or chronic regurgitation. |
| M | Marfan disease | Connective tissue disorder leading to aortic root dilation. |
| I | Iatrogenic | Post-surgical or catheter-related valve injury. |
| S | SLE | Autoimmune inflammation affecting the valve structure. |
| T | Trauma chest | Blunt trauma can rupture valve leaflets or supporting structures. |
| S | Sedation | Rare, linked with severe hypotension and valve injury during procedures. |
| D | Dissection of aorta | Dissection extending to the aortic root can cause acute AI. |
| A | Aneurysm | Aortic root aneurysm stretches valve leaflets apart. |
| R | Rheumatic heart disease | Post-streptococcal inflammation causes leaflet scarring and retraction. |
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Detailed Discussion of Each Cause
1. Congenital Aortic Valve Disease
- Examples: Bicuspid aortic valve, unicuspid valve.
- May remain asymptomatic until adulthood.
- Often associated with aortic stenosis and aortic root pathology.
2. Hypertension
- Chronic high blood pressure accelerates aortic root dilation.
- Promotes degeneration of valve cusps.
3. Endocarditis
- Bacterial or fungal infection destroys valve tissue.
- Acute AI: Severe, rapid onset → pulmonary edema, hypotension.
- Chronic AI: Scarring and deformation over time.
4. Marfan Disease
- Mutation in fibrillin-1 gene → weak connective tissue.
- Leads to aortic root enlargement and cusp malcoaptation.
5. Iatrogenic
- Complication from aortic valve surgery, transcatheter aortic valve implantation (TAVI), or balloon valvotomy.
6. SLE (Systemic Lupus Erythematosus)
- Autoimmune valvulitis → thickened, retracted leaflets.
- Often associated with Libman–Sacks endocarditis.
7. Trauma Chest
- High-velocity blunt chest trauma (e.g., car accidents) can rupture valve leaflets.
8. Sedation
- Rare cause; usually secondary to peri-procedural hypotension causing ischemic injury to the valve.
9. Dissection of Aorta
- Type A dissection involving the ascending aorta can disrupt valve support.
- Presents as acute severe AI.
10. Aneurysm
- Aortic root aneurysm pulls valve leaflets apart.
- Seen in connective tissue disorders, syphilitic aortitis.
11. Rheumatic Heart Disease
- Post-streptococcal inflammation → leaflet fibrosis and calcification.
- AI often coexists with mitral valve disease.
Clinical Presentation
Acute AI
- Sudden dyspnea, hypotension, cardiogenic shock.
- Pulmonary edema.
- Wide pulse pressure may be absent due to rapid hemodynamic collapse.
Chronic AI
- May be asymptomatic for years.
- Symptoms: Exertional dyspnea, palpitations, angina.
- Signs: Bounding pulses, Corrigan’s pulse, wide pulse pressure, displaced apex beat.
Diagnosis
- Echocardiography (TTE/TEE): Confirms diagnosis, assesses severity.
- Chest X-ray: Cardiomegaly in chronic AI.
- ECG: LV hypertrophy.
- Cardiac MRI: Quantifies regurgitant volume and fraction.
Management
Medical
- Vasodilators (ACE inhibitors, nifedipine) in selected patients with hypertension.
- Diuretics for symptom relief in heart failure.
- Regular follow-up for asymptomatic patients.
Surgical
Valve repair or replacement indicated for:
- Symptomatic severe AI.
- Asymptomatic severe AI with LVEF ≤55%.
- Severe AI with LV end-systolic dimension >50 mm.
Acute Severe AI
- Emergency surgery often required.
- Inotropes and vasodilators as a bridge.
Prognosis
- Chronic AI has a gradual course; early detection allows timely surgery and better outcomes.
- Acute AI carries high mortality without urgent intervention.
Quick Reference – CHEMISTS DAR Table
| Letter | Cause |
|---|---|
| C | Congenital aortic valve disease |
| H | Hypertension |
| E | Endocarditis |
| M | Marfan disease |
| I | Iatrogenic |
| S | SLE |
| T | Trauma chest |
| S | Sedation |
| D | Dissection of aorta |
| A | Aneurysm |
| R | Rheumatic heart disease |
FAQs
1. Can aortic insufficiency be reversed?
Mild AI may improve if the underlying cause (e.g., hypertension, endocarditis) is treated early, but significant structural valve damage requires surgery.
2. Is aortic insufficiency the same as aortic regurgitation?
Yes, both terms describe the same condition.
3. Which cause is most common in developed countries?
Bicuspid aortic valve and degenerative disease are common; rheumatic heart disease remains prevalent in developing nations.
4. Can AI be detected during a routine check-up?
Yes, a diastolic murmur on auscultation can lead to echocardiographic confirmation.
5. What is the life expectancy after AI surgery?
With successful surgery and no other major comorbidities, long-term survival is excellent.
