ABSTRACT: Despite continuous development of anticalcification treatment for biological valve prostheses, calcification remains one major cause of structural failure. The following study investigates hemodynamics and changes in opening and closing kinematics in progressively calcified porcine and pericardial valves in a simulated exercise situation.
Five pericardial (Edwards Perimount Magna) and five porcine (Medtronic Mosaic Ultra) aortic valve bioprostheses (23 mm) were investigated in an artificial circulation system (150 beats/min, cardiac output 8l/min). Leaflet kinematics were visualized with a high-speed camera (3000 frames/s). Valves were exposed to a calcifying solution for 6 weeks. Repeated testing was performed every week. All prostheses underwent X-ray and photographic examination including measurement of calcium content for evaluation of progressive calcification.
In the exercise situation pericardial valves demonstrated lower pressure gradients initially compared to the porcine valves (8.5+/-1.4 vs 11+/-1.6 mmHg), but significantly higher closing volume (5.3+/-1.2 ml vs 1.2+/-0.2 ml of stroke volume) leading to an equal total energy. Neither valve type demonstrated a significant increase in gradient or closing volume compared to the normal output situation. Opening and closing times were longer for pericardial valves after 6 weeks (opening time 42+/-10 ms vs 28+/-10 ms, closing time 84+/-12 vs 52+/-10 ms after 6 weeks). Pericardial valves calcified faster and more severely leading to an increase in gradients and closure volume.
In the exercise situation pericardial valves demonstrated superior systolic function compared to porcine valves. Therefore pericardial valves have some advantage in active patients due to the lower gradients. Total energy loss remained constant during progressive calcification for both valves. Leaflet opening and closing is faster in porcine valves; clinical impact of these findings is not known. Diastolic performance is also important and should always be tested also in vivo.
European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 10/2008; 34(5):960-3. · 2.40 Impact Factor
ABSTRACT: Heart failure is common following aortic valve replacement, and optimal prosthesis function is crucial in this critical clinical setting. The study aim was to investigate the hemodynamic performance and leaflet kinematics of fresh and calcified biological aortic valves in a simulated low stroke volume situation.
Edwards Perimount Magna (PM) and Medtronic Mosaic Ultra (MU) valves were investigated in an artificial circulation system (130 beats/min, stroke volume 19 ml), and the results compared to normal output (70 beats/min, stroke volume 70 ml). Leaflet kinematics were visualized using a high-speed camera. All valves were exposed to a calcifying solution for six weeks.
In the low- and normal-output situation, the PM valve initially demonstrated lower pressure gradients compared to the MU valve (low output 2.4 +/- 0.16 versus 3.4 +/- 0.19 mmHg), but showed a significantly higher closing volume (up to 19% of stroke volume) leading to an increased total energy loss. Regurgitation for the PM valve was explained by progressively longer opening and closing times. The PM valve calcified faster and more severely, leading to increasing gradients and closure volume.
In the low stroke volume situation pericardial valves demonstrated superior systolic performance, but inferior diastolic performance, leading to a higher total energy loss compared to porcine valves. This finding may have clinical relevance in heart-failure patients.
The Journal of heart valve disease 06/2008; 17(3):317-24. · 0.81 Impact Factor
ABSTRACT: In vitro testing of biologic valves has been performed using only fresh but treated valves suitable for patient implantation. The present study investigates changes in hemodynamic performance and leaflet kinematics in progressively calcified porcine and pericardial aortic valve prostheses.
Edwards Perimount Magna (Edwards Lifesciences, Irvine, Calif) (n = 5) and Medtronic Mosaic Ultra (Medtronic Inc, Minneapolis, Minn) (n = 5) heart valves (23 mm) were investigated in an artificial circulation system (70 beats/min, cardiac output 5 L/min). Leaflet kinematics were visualized with a high-speed camera (3000 frames/sec). Valves were then exposed to a calcium-phosphate solution at a constant pulse rate of 300 beats/min for a total of 6 weeks. Repeated testing was performed after 1, 2, 3, 4, and 6 weeks of calcification. The calcification process might not be similar to in vivo performance.
Initially, the Perimount Magna valves demonstrated lower pressure gradients compared with the Mosaic Ultra valves (9.7 +/- 0.36 mm Hg vs 14.0 +/- 1.16 mm Hg), but they showed higher closing volume and leakage flow. Total energy loss was equivalent after 1 week of calcification. Perimount Magna valves calcified significantly faster and more severely, leading to an increase in gradients and closure volume. Leaflet kinematics showed progressively longer opening and closing times for the pericardial valves (closing time Perimount Magna 135 +/- 11 msec vs Mosaic Ultra 85 +/- 9 msec after 6 weeks).
On the basis of visual inspection, despite the new ThermaFix (Edwards Lifesciences) tissue treatment, the Perimount Magna pericardial valves calcified in vitro faster and more severely than did the Mosaic Ultra porcine valves, which demonstrated a more constant performance throughout the calcification process. Leaflet kinematics showed a progressive prolongation of opening and closing times for pericardial valves, leading to higher closing volume.
The Journal of thoracic and cardiovascular surgery 10/2007; 134(3):657-62. · 3.41 Impact Factor