Evaluation of ultramicroporous expanded polytetrafluoroethylene mitral valve under pulsatile flow condition in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To test 25# and 27# ultramicroporous expanded polytetrafluo-roethylene mitral valve (UPMV) under pulsatile flow condition in vitro.</p><p><b>METHODS</b>Six 25# and six 27#UPMV were tested using TH-1200 HV Prosthesis Pulsatile Flow Tester in vitro at the cycling rate of 70 cycle/min, with the systolic pressure maintained at about 16 kPa (120 mmHg), diastolic pressure at 10.7 kPa (80 mmHg), and the percentage of mean forward flow at 35%. The stimulant cardiac output was maintained at 2, 3, 4, 5 and 6 L/min, respectively, for the testing.</p><p><b>RESULTS</b>The mean pressure difference for the 25#UPMV under stimulant cardiac output of 2, 3, 4, 5 and 6 L/min was 2.488-/+0.378, 4.427-/+0.240, 5.460-/+0.449, 6.776-/+0.391 and 8.327-/+0.490 mmHg, and its effective valvular orifice was 1.430-/+0.333, 1.993-/+0.208, 2.260-/+0.477, 3.204-/+0.174 and 3.652-/+0.158 cm(2), respectively. The regurgitant fraction of the 25#UPMV under each stimulant cardiac output was (5.731-/+0.643) %, (5.431-/+0.312) %, (5.059-/+0.708) %, (3.545-/+0.097) % and (2.615-/+0.125) %, respectively. The mean pressure difference of the 27#UPMV under each stimulant cardiac output was 1.618-/+0.497, 3.448-/+0.440, 4.825-/+0.434, 5.494-/+0.446 and 7.482-/+0.455 mmHg, effective valvular orifice was 1.773-/+0.364, 2.113-/+0.305, 2.409-/+0.295, 3.326-/+0.417 and 4.522-/+0.445 cm(2), and regurgitant fraction was (5.357-/+0.509) %, (5.407-/+0.110) %, (4.999-/+0.182) %, (4.010-/+0.254) % and (2.584-/+0.114)%, respectively.</p><p><b>CONCLUSION</b>The mean pressure difference, effective valvular orifice and regurgitant fraction of the UPMVs can measure up to the national criteria for artificial heart valve prosthesis of China.</p>

Accelerated fatigue test in vitro of expanded polytetrafluoroethylene artificial heart valve / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the durability of expanded polytetrafluoroethylene artificial heart valve (ePTFE AHV).</p><p><b>METHODS</b>Six ePTFE AHVs were tested for 400 million times against accelerated fatigue using TH-2200 artificial heart valve exosomatic accelerated fatigue instrument. Hydromechanical parameters of fore-and-aft accelerated fatigue test of the 6 AHVs were obtained by TH-1200 artificial heart valve exosomatic pulsatile stream instrument.</p><p><b>RESULTS AND CONCLUSION</b>The mean gradient pressure spanning the valve and the effective orific area of ePTFE AHVs did not undergo significant changes after fore-and-aft the fatigue test, but the regurgitation volume and regurgitation rate of ePTFE AHVs were reduced after the accelerated fatigue test, suggesting good durability of ePTFE AHV.</p>