What is the immediate management of acute severe aortic regurgitation?

Management of Acute Aortic Regurgitation

Acute severe aortic regurgitation is a surgical emergency requiring urgent aortic valve replacement; medical therapy serves only as a temporizing bridge to definitive surgery and should not delay operative intervention, particularly when hypotension, pulmonary edema, or low cardiac output are present. 1

Immediate Diagnostic Approach

Transthoracic or transesophageal echocardiography is mandatory to confirm the diagnosis, assess severity, identify the etiology (endocarditis vs. aortic dissection), and evaluate left ventricular function and size. 1

Key echocardiographic findings indicating severe acute AR and hemodynamic compromise include:

• Pressure half-time <300 ms on the AR velocity curve, indicating rapid equilibration of aortic and LV diastolic pressures 1
• Premature mitral valve closure and short deceleration time on mitral inflow, both markers of markedly elevated LV end-diastolic pressure 1, 2
• Diastolic mitral regurgitation (DMR), which independently predicts decompensation (OR 4.71) 2
• Holodiastolic flow reversal in the aortic arch compared to forward systolic flow provides semi-quantitative assessment of regurgitant fraction 1

For suspected aortic dissection causing acute AR, CT imaging is the primary diagnostic modality (sensitivity/specificity >95%), as it is highly accurate and continuously available; TEE has sensitivity 98-100% and specificity 95-100% when CT is unavailable or for intraoperative assessment. 1

Risk Stratification for Decompensation

Patients at highest risk of rapid hemodynamic deterioration can be identified by:

• Heart rate ≥94 bpm (independent predictor, OR 1.08 per bpm increase; 75.9% decompensation rate vs. 10% when HR ≤81 bpm) 2
• Diastolic blood pressure ≤54 mmHg (61.3% decompensation rate vs. 17.9% when DBP ≥63 mmHg) 2
• Presence of diastolic mitral regurgitation (27.8% vs. 7.4% in stable patients) 2
• Mitral E-wave velocity >113 cm/s and E/e' ratio >12, indicating elevated filling pressures 2

These patients require emergent surgery without delay. 2

Medical Stabilization (Bridge to Surgery Only)

Medical therapy to reduce left ventricular afterload may be administered for temporary stabilization, but surgery must not be delayed. 1

Specific medical management:

• Vasodilators (nitroprusside, ACE inhibitors, or dihydropyridine calcium channel blockers) to reduce afterload and improve forward flow 1, 3, 4
• Positive inotropes (dobutamine) if low cardiac output or cardiogenic shock is present 4, 5
• Diuretics cautiously for pulmonary edema, but avoid excessive preload reduction 4
• Antibiotics immediately if infective endocarditis is suspected or confirmed 4, 5

Critical contraindications:

• Intra-aortic balloon pump is absolutely contraindicated in acute severe AR, as diastolic augmentation worsens regurgitant volume 1
• Beta-blockers should be avoided or used very cautiously (except in aortic dissection), as they prolong diastole and increase regurgitant volume 1, 3, 4

Definitive Surgical Management

Urgent surgical aortic valve replacement is indicated for all patients with acute severe AR, regardless of left ventricular systolic function. 1, 3

Surgery should be performed emergently when:

• Hypotension is present 1
• Pulmonary edema develops 1
• Evidence of low cardiac output or cardiogenic shock exists 1
• Heart rate ≥94 bpm or diastolic mitral regurgitation is present 2

For acute AR due to aortic dissection (Type A), this is a surgical emergency requiring immediate intervention with both aortic root/ascending aorta repair and aortic valve management. 1

For acute AR due to infective endocarditis, surgery should not be delayed even in the setting of active infection, as mortality risk with medical management alone is prohibitive. 1, 6

Special Circumstances

In rare cases of prohibitive surgical risk with cardiogenic shock, percutaneous mechanical circulatory support (e.g., Impella) combined with transcatheter valve occlusion or valve-in-valve TAVI may serve as a bridge to definitive surgery when the patient can be stabilized. 7

However, TAVI should not be performed as definitive therapy in patients with isolated severe AR who are surgical candidates (Class III recommendation). 1, 3

Common Pitfalls to Avoid

• Do not delay surgery for medical optimization in hemodynamically unstable patients—this increases mortality 1
• Do not place an intra-aortic balloon pump—this is contraindicated and worsens outcomes 1
• Do not rely on TTE alone for aortic dissection diagnosis (sensitivity only 60-80%); use CT or TEE 1
• Do not use beta-blockers routinely except in aortic dissection, as they worsen regurgitant volume 1, 3, 4
• Do not wait for "optimal" timing in active endocarditis—surgery is indicated despite active infection 1, 6