Heart Valve Evaluation

Exponent’s biomedical engineering (BME) practice and laboratory facilities have the procedures, equipment, and consultants needed to assess new heart valve technologies, including transcatheter aortic and mitral heart valves (TAVR and TMVR) and surgical mechanical and bioprosthetic valves. Exponent can design and perform verification and validation tests in accordance with ISO 5840-2:2015, Cardiovascular implants -- Cardiac valve prostheses: Surgically implanted heart valve substitutes, and ISO 5840-3:2013, Heart valve substitutes implanted by transcatheter techniques.

Evaluations of heart valves typically include both computational modeling and experimental tasks. Exponent’s BME lab is ISO 17025 accredited (A2LA Certificate: 2561.01) for conducting test programs which comply with ISO 5840 for regulatory submission. To compliment modeling, the BME laboratories are equipped with instrumentation, imaging and mechanical testing capabilities to comprehensively evaluate a heart valve device and its components. This includes evaluating diseased conditions and irregular geometries.
Our valve testing capabilities include: 

Accelerated Wear Testing
Heart ValveEquipment: TA Durapulse Test System

  • Customized fixtures and vessels for mounting implants
  • Temperature-controlled and monitored stations that can be maintained at 37 ± 2°C 
  • Testing profiles for aortic and mitral valves at accelerated frequencies
  • Programmable input pressure profiles

Physiologic Flow Testing

Equipment: Custom Pulse Duplicator

  • Valve fixtures are compatible with the Durapulse system to allow seamless transition of samples between accelerated wear testing and pulse duplication evaluation
  • Physiologic hemodynamic pressure and flow waveforms for aortic and mitral valves
  • Programmable input displacement profiles

Steady Flow Testing
Equipment: Custom Steady-Flow Tester

  • Forward flow performance and leakage flow testing at varying pressures and flow rates
  • Systolic and diastolic migration

Mechanical Testing
Heart ValveEquipment: Servohydraulic and Electromechanical test systems equipped with custom fixture sets

  • Device anchoring quantification
  • Stent strut bending properties
  • Wear testing of stent struts
  • Valve pullout force/anchoring quantification
  • Material characterization

Imaging Capabilities

  • High speed cameras for valve imaging during testing
    • Evaluation of opening and closing dynamics
    • Evaluation of effective orifice area
  • High-speed flow visualization
  • Keyence digital microscope
    • Low and high magnifications (1-1000x)
  • Scanning electron microscopes 
    • High-magnification surface imaging (e.g., 5000x)
  • White-light interferometry
    • Average surface roughness evaluation (manufactured vs. worn)
  • Micro-CT
  • Fluoroscopy
    • Deployment verification
    • Regurgitation assessment
    • Simulated deployment

Project Experience

  • Retrieval analysis of heart valves
  • Computational fluid dynamics 
  • Corrosion testing before and after fatigue testing
  • Stent coating analysis
  • Annuloplasty device testing
  • Materials testing
  • Tissue characterization
  • MRI compatibility testing
  • Custom flow chamber and flow loop design.



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