Clinical application history of prosthetic heart valves has been over five decades, and mechanical heart valves have satisfactory clinical outcomes for surgical treatment of valvular heart disease. The development history of mechanical heart valves experienced from the first generation of ball valves and caged disc valves to the second generation of single tilting disc valve, and to the third generation of bileaflet valves. In 1960， ball valve was first used for heart valve replacement in abroad. In 1963， China-made ball valve was also produced and used in clinical practice. In 1969， the second generation of single tilting disc valve was developed in abroad. In 1978， China-made single tilting disc valve was produced and widely used in clinical practice with satisfactory clinical outcomes. Since 1980 when it was first produced， bileaflet valve has taken the place of above 2 types of valves for its excellent performance, and become the mainstream product all over the world. Currently, the development of China-made bileaflet valves has lagged behind， and domestic mechanical heart valve market has almost been monopolized by foreign bileaflet valve products. Therefore, the development of ideal China-made mechanical heart valve deserves further research.
The pulsatile flow experiment can not only evaluate the preclinical safety and risk of prosthetic heart valve (PHV) but also play an important role in the computational model and fluid simulation, providing an experimental basis for the performance optimization of PHV. This paper mainly reviews the development and the latest progress of PHV pulsatile flow experiments and the characteristics of experimental pulse duplicator, and discuss the research direction of pulsatile flow experiments, expecting a further development in this field.
Abstract： Objective To evaluate early clinical outcomes and short-term follow-up results of CL-V bileaflet prosthesis. Methods From April 2004 to May 2010， 38 patients with valvular heart diseases underwent mechanical heart valve replacement. Eighteen patients received CL-V bileaflet valve replacement （CL group） including 8 males and 10 females with their mean age of （47.4±6.2）years and mean body weight of （64.7±11.9） kg. Preoperatively，15 patients were in New York Heart Association （NYHA） classⅢ， and 2 patients were in NYHA classⅣ. Mitral valve replacement （MVR） was performed in 16 patients， mitral and aortic valve replacement（DVR） in 2 patients. A total of 20 CL-V bileaflet prostheses were implanted. Twenty patients received St. Jude bileaflet valve replacement （SJM group）including 9 males and 11 females with their mean age of （49.7±7.6） years and mean body weight of （66.1±11.1） kg. Preoperatively， 15 patients were in NYHA classⅢ， and 3 patients were in NYHA classⅣ. MVR was performed in 17 patients，aortic valve replacement （AVR） in 1 patient， and DVR in 2 patients. A total of 22 St. Jude bileaflet prostheses were implanted. Clinical outcomes， hear function， hemodynamics and blood compatibility were measured on the 7th postoperative day and 6 months during follow-up and compared between the two groups. Results There was no early mortality （＜30 d） or postoperative complication in either group. Follow-up rate was 100% and the mean follow-up duration was 19.8 （6-61）months. At 6 months after surgery， those patients who were preoperatively in NYHA classⅢ orⅣall improved to classⅠ orⅡ. In CL group， cardiothoracic ratio was 0.51±0.05， left atrium diameter （44.5±7.8） mm， left ventricular end diastolic diameter （LVEDD，46.6±4.1） mm， LVEF 65.3%±7.7%，and LVFS 35.0%±7.1%. In SJM group， cardiothoracic ratio was 0.51±0.06， left atrium diameter （45.8±9.6） mm， LVEDD （46.2±9.8） mm， LVEF 64.1%±9.0%，and LVFS 34.9%±4.7%， which were not statistically different from those parameters of CL group respectively （P＞0.05）. At 6 months after surgery， transthoracic echocardiography was used to compare hemodynamics of bileaflet prostheses with same size 27 mm in the two groups. Prosthetic transvalvular gradient was （5.1±0.9）mm Hg in CL group and （5.8±0.8） mm Hg in SJM group， and effective orifice area was （2.3±0.3）cm2 in CL group and（2.5±0.2）cm2 in SJM group，which were not statistically significant between the two groups （P＞0.05） respectively. In both groups， the level ofhemoglobin， lactate dehydrogenase and platelet at 6 months postoperatively were all within normal range and not statistically from those respective preoperative parameters（P＞0.05）. Hemolytic reaction and hemolytic anemia were not found. During early and short-term follow-up， there was no thromboembolic complications or anticoagulation-related severe bleeding events in the two groups with same anticoagulation intensity target （target INR value 1.5 to 2.5）. Conclusion Early clinical outcomes and short-term follow-up results of CL-V bileaflet prostheses are similar to those of St. Jude bileaflet prostheses. Postoperative patients have good clinical outcomes， hemodynamics and blood compatibility. Patients’ heart function significantly improve during short-term follow-up without valve-related complication. Mid-term and Long-term follow-up are further needed to demonstrate its good performance.