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.
Heart valve replacement is the major surgical treatment of severe valvular diseases. Due to the durability and reoperation-free, mechanical valves are widely used. Bioprosthesis valves became popular recently because of long service life and no demand for lifelong anticoagulation. However, how to choose the appropriate prosthetic heart valves, especially the application of bioprosthesis valves for patients at 55 to 65 years is still a major problem. This review focuses on more effective and scientific basis for rational choice of mechanical and bioprosthesis valve.
The possibility of polyoxymethylene (POM) as heart valve leaflet material was investigated by comparing the hemocompatibility with that of 316L stainless steel and low-temperature isotropic pyrolytic carbon (LTIC). Surface hydrophobicity was characterized by water contact angle measurement.Platelet adhesion, APTT/PT/TT and hemolysis rate tests were applied for evaluating hemocompatibility. The results showed that POM was hydrophobic and had a low hemolytic rate, adhesion amount and activation degree of platelets on POM surface were less than 316L stainless steel, and was similar to LTIC. This research pointed out potential application of POM as heart valve leaflets.
The heart valve prosthesis must have excellent hydrodynamic performance which is usually tested in vitro, not in vivo. This paper comprehensively introduced the principles and methods of hydrodynamic performance in vitro testing, helping clinicians to understand valve performance parameters, evaluate valve applicability, and reduce clinical risk of the valve prosthesis. In vitro testing not only serves as the "gold standard" for valve prosthesis assessment, but also provides detailed data for design and optimization of the prosthesis. ISO 5840 defines the items and methods for valve in vitro testing, which consists of three parts: (1) pulsatile flow testing, which reproduces the pulsating flow of the valve prosthesis after implantation in the human body; (2) steady flow testing, which assesses valve forward flow resistance; (3) durability testing, which evaluates the durability of the valve prosthesis and determines the expected failure mode. In addition, the paper presented the differences between atrioventricular and aortic valve testing, the method of mitral valve testing, the differences between transcatheter and surgical valve testing, and the method of valve flow visualization.
ObjectiveTo analyze the reason and prevention of late bioprosthetic heart valve thrombosis (LBVT). MethodsBioprosthetic heart valves were implanted in 580 patients between January 2001 and July 2013 in Changhai Hospital, and only found one case of LBVT (0.2%). Reoperation was performed for a 67-year-old male patient 3 years after bioprosthetic aortic valve replacement due to severe aortic valve stenosis. Retrospectively analyzed the clinical data and reviewed the literature between January 1989 and December 2013 in Pubmed. ResultsNo risk factor for thrombosis was revealed in this patient. Pathology revealed valve thrombosis and collagen and elastic fibers fragmentation and disruption in valve leaflets. In literature review, 20 articles and 47 cases were brought in. The morbidity of LBVT was 0.2%-1.0%. At least 18 patients had high risk factors, and 15 of the 18 patients discontinued anticoagulation after 3 months. However, at least 10 patients had no high risk factors. Forty-four of the 47 patients received stented porcine valve replacement, only one patient received stented bovine pericardial valve replacement. ConclusionsLBVT is a rare but serious complication after bioprosthetic valve replacement, the causes of which include the feature of the patients and the bioprosthetic valves. Bovine pericardial valves could be superior to porcine valves in preventing LBVT. Postoperative long-time aspirin therapy is recommended for patients without high risk factors. Patients with any high risk factors should prolong anticoagulation.
In recent years, the field of cardiovascular surgery has undergone revolutionary changes and made rapid progress in various aspects, bringing more hope and possibilities for the health and well-being of patients. The constant emergence of new technologies brings new opportunities and hope, as well as constant challenges to past concepts. This article aims to provide a comprehensive overview of the latest developments in cardiovascular surgery in recent years, especially since 2023. It introduces cutting-edge knowledge and technologies in the field of cardiovascular surgery, including lifelong management of aortic valve disease, artificial valves, mitral valves, treatment options for hypertrophic obstructive cardiomyopathy, heart transplantation, left ventricular assist, coronary artery surgery, cardiac structural interventions for chronic heart failure, aortic dissection, and comprehensive surgical treatment of atrial fibrillation. It also analyzes and explores future development directions in depth, aiming to provide useful references and inspiration for cardiovascular doctors and jointly promote the continuous progress of cardiovascular surgery in China.
ObjectiveTo investigate hemodynamic changes in the early postoperative period of isolated aortic valve replacement (AVR) with different types of 19-mm mechanical heart valves. MethodsClinical data of 116 patients with aortic stenosis who underwent AVR in Beijing Anzhen hospital from January 2007 to January 2012 were retrospectively analyzed. There were 61 male and 55 female patients with their age of 52±13 years. All the patients were divided into 3 groups according to different types of mechanical heart valves they received. In SJ. Regent valve group,there were 38 patients (33%) including 20 males and 18 females with their average age of 52±15 years. In Carbomedics valve group,there were 40 patients (34%) including 21 males and 19 females with their average age of 51±17 years. In On-X valve group,there were 38 patients (33%) including 20 male and 18 female patients with their average age of 55±16 years. Preoperative and postoperative left ventricular end-systolic diameter (LVESD) left ventricular end-diastolic diameter (LVEDD) ejection fraction (EF) interventricular septal thickness,left ventricular wall thickness,trans-aortic valve velocity and pressure,and postoperative effective orifice area index (EOAI) were compared. ResultsThere was no statistical difference in preoperative and postoperative LVESD,LVEDD,EF,interventricular septum thickness and left ventricular wall thickness among the 3 groups (P>0.05). There was statistical difference in preoperative and postoperative trans-aortic valve velocity and pressure. Trans-aortic valve velocity of SJ. Regent valve group and Carbomedics valve group (244.30±33.67 cm/s vs. 249.69±79.13 cm/s vs. 294.83±52.05 cm/s) and trans-aortic valve pressure of SJ.Regent valve group and Carbomedics valve group (27.77±3.33 mm Hg vs. 33.58±18.90 mm Hg vs. 38.56±13.21 mm Hg) were significantly smaller than those of On-X valve group. ConclusionSt. Regent and Carbomedics mechanical heart valves demonstrate better hemodynamics in AVR patients receiving 19-mm mechanical heart valves.
Abstract: Objective To investigate the anticoagulation effect of warfarin on pregnant women with prosthetic mechanical heart valves during the whole course of pregnancy and their fetuses. Methods Followup survey was carried out on 103 pregnant women with prosthetic mechanical heart valves treated in the Second Xiangya Hospital of Central South University from April 1998 to June 2010. Their age ranged from 19 and 38 years (26.4±3.8 years). All the 103 pregnant women were given oral administration of warfarin during the whole course of pregnancy. The average dose of domestic warfarin was 3.30±0.43 mg/d (87 cases), while the average dose of imported warfarin was 2.90±1.05 mg/d (16 cases). Results None of the patients suffered from serious embolic events. One patient suffered from spontaneous peritoneal hemorrhage. There were 4 cases of intrauterine deaths, and 5 cases of fetal malformation including 1 case of Down’s syndrome and 4 cases of hydrocephalus. Six cases of low birth weight infants and 1 case of ABO hemolytic disease were also found. All the other neonates were healthy with normal weight. No pregnant women suffered from postpartum hemorrhage. Conclusion Oral administration of low dose warfarin (lt;5 mg/d) during the whole course of pregnancy is a relative safe and effective anticoagulation protocol.
Abstract:Objective To investigate the reoperation indication,surgical timing and the key point of surgical treatment of prosthetic valve endocarditis （PVE） after valve replacement. Methods From February 2000 to July 2005,18 patients with PVE underwent surgery ,their clinical manifestation ,process of treatment and their prognosis outcome were analyzed. Results There were 3 patients （16.7 %） of early-death, 1 patient died of septic shock, and 2 patients died of multiple organ failure. Since 2003,there was no operative death for all 11 patients. There were 6 patients with respiratory insufficiency, 2 patients with renal insufficiency,which were recovered after treatment. The 15 survivors were followed up from 1 month to 5years. There was recurrence of infection in 1 patient who died after ineffective medical treatment. The other 14 patients recovered well. Conclusion It has high risk and high mortality for reoperation for PVE. Accurate reoperative indication,optimal surgical timing,radical debridment of infected tissue and correct perioperative use of antibiotics are the key factors to improve the reoperative result for PVE.
Abstract:Since 1978 the definition of prosthesis-patient mismatch（PPM） was first introduced by Rahimtoola, it has attracted the attention of foreign researchers. The PPM phenomenon is concerned to be an important factor which will affect patients＇ survival rate and quality of life. Till now, a lot of effort should still be put on this problem. But unfortunately, this problem is still being neglected in our country. This paper is a review of PPM from it＇s many aspects, such as definition, current research status, prevention, and it＇s research prospect. We hope this paper will intensify the clinicians＇ knowledge on PPM.