Will a biosynthetic (bio-prosthetic) aortic valve (AV) sound different?

Acoustic Differences Between Biosynthetic Aortic Valves and Other Valve Types

Yes, a biosynthetic (bio-prosthetic) aortic valve will sound different from a mechanical valve during auscultation due to its structural design and functional characteristics. 1

Acoustic Characteristics of Different Valve Types

Biosynthetic Valves

• Produce sounds similar to native valves with a softer closing sound
• Have a trileaflet structure that creates a box-like opening pattern in systole (aortic position)
• Generate less acoustic shadowing during echocardiography compared to mechanical valves 1
• Do not produce microbubbles (which can create additional sounds in mechanical valves) 1
• Lack the distinct metallic "clicking" sounds characteristic of mechanical valves

Mechanical Valves

• Produce distinct opening and closing clicks that are easily audible with a stethoscope 1
• Different types of mechanical valves have distinctive acoustic signatures:
  • Bileaflet valves: Two separate disks creating synchronized clicks
  • Tilting disc valves: Single movement creating a distinct click
  • Ball-cage valves: Produce multiple distinct echoes 1

Imaging Differences That Correlate With Acoustic Properties

The physical properties that create different sounds also affect imaging:

• Biosynthetic valves:

  • Frame and struts are echogenic but produce less acoustic shadowing than mechanical valves
  • Leaflets appear thin (1-2 mm) with unrestricted motion 1
  • Appear similar to native aortic valves, especially stentless varieties
  • Generate lower artifacts on CT and MRI imaging 1

• Mechanical valves:

  • Create significant acoustic shadowing on echocardiography
  • Produce strong reverberations and artifacts
  • Show characteristic opening and closing patterns on M-mode imaging 1
  • Generate more pronounced artifacts on CT and MRI due to metal components

Clinical Implications

The acoustic differences between valve types have important clinical implications:

• Diagnostic value: The distinctive sounds help clinicians identify valve type and function during routine examination
• Patient experience: Mechanical valve clicks may be audible to patients themselves, potentially affecting quality of life 2
• Follow-up monitoring: Different auscultation findings guide assessment of valve function over time
• Valve selection considerations: Acoustic properties are rarely the primary factor in valve selection, which typically focuses on durability, anticoagulation requirements, and patient age 1

Important Considerations for Valve Selection

While sound differences exist, valve selection should prioritize:

• Patient age: Mechanical valves typically recommended for patients <50 years due to durability 1
• Anticoagulation: Bioprosthetic valves avoid need for lifelong anticoagulation 1
• Durability: Mechanical valves offer greater durability but require anticoagulation 1
• Reoperation risk: Bioprosthetic valves have higher reoperation rates (structural valve degeneration occurs at 10-12 years in younger patients, 15-18 years in older patients) 1

Pitfalls in Auscultation of Prosthetic Valves

• Misinterpreting normal mechanical valve clicks as pathological sounds
• Failing to recognize subtle changes in biosynthetic valve sounds that might indicate degeneration
• Not accounting for the specific valve type when evaluating murmurs or other sounds
• Overlooking that biosynthetic valves may develop calcification over time, altering their acoustic properties

Remember that while the acoustic differences are clinically relevant, they should be considered alongside imaging findings and clinical parameters when evaluating prosthetic valve function.