Ex vivo hemodynamic assessment of mechanical aortic valve gradients using a high-fidelity pressure wire.
OBJECTIVE
Accurate assessment of prosthetic mechanical valve malfunction is challenging for non-invasive and invasive techniques. We evaluated a 0.014-inch pressure-sensing coronary guidewire to assess mechanical valve dysfunction.


BACKGROUND
Several case reports have shown that transaortic pressure gradients can be recorded using a 0.014-inch guidewire during cardiac catheterization.


METHODS
We performed an ex vivo study measuring the effects of sequentially crossing the center of each valve with a 6 French coronary angiographic catheter, a 0.035-inch guidewire, and a 0.014-inch pressure-sensing guidewire on valve dysfunction using the following 23 mm bileaflet and tilting-disc aortic valves: St. Jude Regent™, CarboMedics, Medtronic Hall™, and Björk-Shiley Monostut. A left heart model pulse duplicator recorded 10 consecutive cycles.


RESULTS
For all valves, the greatest increase in valve regurgitation occurred with the 6 French catheter, causing a reduction in aortic valve back pressure and cardiac output, with an increase in leakage rate, regurgitant fraction, and energy loss. In comparison to the 0.035-inch guidewire, the 0.014-inch guidewire had greater regurgitation for St. Jude, lower for Medtronic Hall, and equivalent for CarboMedics and Björk-Shiley valves. For the CarboMedics valve, the 0.035-inch guidewire caused a significant increase in regurgitant fraction and energy loss, while the pressure wire had no change compared to baseline.


CONCLUSIONS
The degree of regurgitation caused by the 0.014-inch guidewire varies with the type of mechanical aortic valve. While prior case reports have shown that valve hemodynamics may be measured using a pressure-sensing guidewire, valve regurgitation occurs when crossing a St. Jude, Medtronic Hall, or Björk-Shiley aortic valve.
Humboldt Medical Specialists, Eureka, California, USA. andrew.michaels@stjoe.org
Andrew D
AD
Michaels
David
D
Mester
D000208:Acute Disease; D001022:Aortic Valve Insufficiency / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation*; D057785:Catheters; D017023:Coronary Angiography / Q000295:instrumentation; D004867:Equipment Design; D006350:Heart Valve Prosthesis; D006439:Hemodynamics; D008422:Materials Testing; D011475:Prosthesis Failure; D013997:Time Factors; D014160:Transducers, Pressure; D014741:Video Recording