How is aortic regurgitation severity graded on an aortogram?

Aortic Regurgitation Grading on Aortogram

On aortography, severe aortic regurgitation is graded as Sellers grade 3-4 (also referred to as angiographic grades 3-4), which is one of the markers used to support the diagnosis of severe AR according to current guidelines 1.

Angiographic Grading System (Sellers Classification)

The traditional Sellers classification grades AR from 1+ to 4+ based on the degree and persistence of contrast opacification in the left ventricle:

• Grade 1+: Minimal contrast enters the LV and clears with each beat
• Grade 2+: Contrast enters the LV but doesn't fully opacify it, and clears over several beats
• Grade 3+: Progressive opacification of the LV with contrast density equal to the aorta
• Grade 4+: Complete opacification of the LV on first beat with greater density than the aorta

Grades 3-4 are considered severe AR 1.

Important Limitations and Clinical Context

Significant Overlap Between Grades

Angiographic grading has substantial limitations that you must recognize. Research demonstrates that regurgitant volume varies widely within each angiographic grade, with considerable overlap between grades 2. Specifically:

• Grades 1+ and 2+ AR showed no significant difference in regurgitant volume (0.87 vs 1.72 L/min/m²)
• Grades 3+ and 4+ AR also showed no significant difference (3.0 vs 4.80 L/min/m²)
• There is particularly wide variation in grades 3+ and 4+ 2

Moderate Correlation with Quantitative Methods

When compared to cardiac magnetic resonance (CMR) - the gold standard for AR quantification - aortic root angiography shows only moderate correlation (r=0.41-0.42) 3. Using Sellers grade ≥2 as a cutoff has:

• Sensitivity: 71% for detecting moderate-to-severe AR
• Specificity: 98% 3

This means angiography can miss significant AR in nearly 30% of cases.

Current Guideline Recommendations

The 2020 ACC/AHA guidelines indicate that aortic angiography can provide additional information when TTE is suboptimal or when there's discrepancy between clinical findings and echocardiography 4. However, it is not the primary diagnostic modality.

The guidelines recommend cardiac catheterization as Class IIa (reasonable) to assess hemodynamics and AR severity only when:

• TTE images are suboptimal, AND/OR
• There is discrepancy between symptoms and echo findings 1

Practical Algorithm for AR Assessment

Start with transthoracic echocardiography (TTE) as your primary diagnostic tool 4:

1. TTE is Class I indication for assessing AR cause, severity, LV size, and systolic function
2. If TTE is adequate and correlates with clinical findings → use echo parameters for severity grading
3. If TTE is suboptimal or discordant with clinical picture → proceed to:
   • TEE (transesophageal echo)
   • CMR (cardiac magnetic resonance) - preferred for quantification
   • Cardiac catheterization with aortography - when other modalities unavailable or contraindicated

Multimodality Severe AR Criteria

Severe AR should be diagnosed using multiple converging parameters 1:

• Vena contracta ≥0.6 cm
• Regurgitant volume ≥60 mL/beat
• Effective regurgitant orifice area (EROA) ≥0.3 cm²
• Regurgitant fraction ≥50%
• Holodiastolic flow reversal in descending aorta
• Pressure half-time <200 ms
• Angiographic grades 3-4
• Evidence of LV dilation

Key Clinical Pitfall

Do not rely on angiographic grading alone to make treatment decisions. The qualitative nature of angiographic assessment, combined with its moderate correlation with quantitative methods and significant inter-grade overlap, means it should be integrated with other imaging modalities - particularly echocardiographic quantitative parameters or CMR - rather than used in isolation 2, 3. When uncertainty exists in AR grading on angiography, multimodality imaging including hemodynamic analysis should be considered 3.