Valvular heart disease is a structural or functional disease of the heart due to rheumatic fever, congenital malformation, infection, or trauma, resulting in abnormal cardiac hemodynamics and ultimately heart failure. Implantation of artificial heart valves has become the main way to treat heart valvular disease. Because the structure of the artificial heart valve plays a key role in the stress distribution and hemodynamic performance of the valve and stent, the geometric configuration of the artificial heart valve is constantly updated and improved during its development from mechanical valve to biological valve, which closely mimics the geometric characteristics of the normal natural heart valve. This article sums up the design process of geometric configuration of artificial heart valves and the influence of geometric configuration on the central disc stress and durability of artificial heart valves, analyzes the important parameters of geometric modeling for artificial heart valves, and discusses the development of the corresponding modeling method, to provide reference and new ideas for the biomimetic optimization design of artificial valves.
OBJECTIVE: To explore the possibility of detergent acellularized porcine heart valve serving as a scaffold for tissue engineering valve. METHODS: The porcine aortic valves were acellularized by use of trypsin-EDTA. Triton X-100, RNase and DNase treatment. Biomechanical characteristics of fresh valves and acellularized valve were tested; also fresh valves, acellularized valve and valves treated with method of bioprothetic treatment were implanted subcutaneously in rats; frequently seeded with bovine aortic endothelial cells(BAECs), and then cultured for 7 days. RESULTS: The acellularization procedure resulted in complete removal of the cellular components while the construction of matrix was maintained. The matrix could be successfully seeded with in vitro expanded BAECs, which formed a continuous monolayer on the surface. There is no significant difference of PGI2 secretion of BAECs between cells seeded onto the acellular leaflets and that onto the wells of 24-wells plate (P gt; 0.05). CONCLUSION: Acellularied porcine aortic valve can be applied as a scaffold to develop tissue engineering heart valve.
Based on the analysis of the influence of the valve pivot distance on the performance of mechanical heart valve (MHV), such as the valve opening and closing features, flow field characteristics and the valve assembly properties, value constraints of the valve pivot distance were established, and the reasonable valve was obtained by means of the finite element method. It can be shown that the central flow characteristics of the valve could be enhanced with the increasing of the ratio of pivot distance to valve inner diameter, but the plastic deformation of the ring could be liable to occur in the MHV assembly process. It is proved that the valve of specifications can be designed in similar ratio of pivot distance to valve inner diameter according to the result of the valve performance experiment.
ObjectiveTo explore optimal intensity of oral anticoagulation for patients with prosthetic heart valves in Northeast China. MethodsA total of 856 patients in Northeast China who underwent prosthetic heart valve replacement in the Department of Cardiovascular Surgery,Second Hospital of Jilin University from January 2005 to June 2013 were enrolled in this study. There were 406 male and 450 female patients with their age of 45.2±13.3 years. All the patients received low-intensity oral anticoagulation [international normalized ratio (INR) 1.5-2.2,aortic valve replacement (AVR):1.5-1.8,mitral valve replacement (MVR):1.8-2.2]. Patients were followed up after discharge,and the incidence of anticoagulation-related complications was summarized. ResultsThese patients were followed up for 1-78 (18.3±12.2) months,and the follow-up rate was 75.4%. Twelve patients (1.86%) had thromboembolic complications and 10 patients (1.55%) had hemorrhagic complications. Average warfarin dosage was 3.4±0.8 mg/day,and average INR was 1.94±0.54 during follow-up. ConclusionFor patients with prosthetic heart valves in Northeast China,low-intensity anticoagulation can produce satisfactory clinical outcomes to reduce the incidence of anticoagulation-related thromboembolic or hemorrhagic complications.
ObjectiveTo explore the effect of pulmonary hypertension on the clinical efficacy of Cox Maze Ⅳ procedure in treating atrial fibrillation (AF) patients with valvular heart disease.MethodsThe clinical data of 84 patients who received cardiac valve replacement and Cox Maze Ⅳ ablation in our hospital from July 2017 to January 2020 were retrospectively analyzed. According to the estimation of pulmonary artery pressure (PAP) by ultrasound, the patients were divided into two groups: a group A (PAP<45 mm Hg, 20 males, 26 females with an average age of 59.1±7.8 years) and a group B (PAP≥45 mm Hg, 15 males and 23 females with an average age of 58.5±8.5 years). The PAP was less than 70 mm Hgin all patients. A systematic follow-up review was performed for 6 months after operation. The recovery and recurrence rate of sinus rhythm after surgical ablation were compared between the two groups, and the efficacy was analyzed.Results(1) All the patients completed the operation successfully, and there was no statistical difference in the ablation time between the two groups (P>0.05); no patients died of pulmonary infection after the operation, and one patient underwent implantation of a permanent pacemaker due to conduction block. (2) At the end of the operation and 3 months after the operation, the conversion rate of AF in the group A was 91.3% (42 patients) and 82.6% (38 patients), respectively, and in the group B was 89.5% (34 patients) and 73.7% (28 patients), respectively (P>0.05). The conversion rate of AF was 82.6% (38 patients) in the group A and 63.2% (24 patients) in the group B at 6 months after operation (P=0.043). Binary logistic regression analysis showed that PAP≥45 mm Hg had a significant effect on the long-term effect of surgical Maze procedure in treating AF patients with valvular heart disease [P=0.014, OR=5.661, 95%CI (1.429, 22.432)].ConclusionPAP may be an influencing factor for the long-term effect of surgical Maze procedure in treating AF patients with valvular heart disease. Although the long-term recurrence rate of AF in the moderate pulmonary hypertension group is higher than that in the group A, the overall effect is still safe and effective; therefore it is still worth promoting in clinical application.
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 transcatheter heart valve interventional therapy has developed rapidly. Valvular thrombosis is a rare postoperative complication, which can affect valvular function early or lead to clinical embolic events, and is gradually being valued by surgeons. The clinical manifestations of thrombosis after different types of interventional valve replacement are different. Although anticoagulant therapy is believed to be effective for valve thrombosis, the selection of anticoagulant drugs and the duration of anticoagulation are still controversial. This article reviews the definition, clinical features, prevention and treatment of valve thrombosis after several types of transcatheter heart valve replacement, mainly related to transcatheter aortic valve replacement and transcatheter mitral valve replacement, and aims to provide a reference for the diagnosis and treatment of valve thrombosis after transcatheter heart valve replacement.
The study of mechanical properties on heart valves can provide an important theoretical basis for doctors to repair heart valves and prosthetic valve materials research. In this paper, we present the current status of the mechanical property study methods of heart valve, expound the methods and special requirements about uniaxial tensile test and biaxial tensile test of the heart valve, and further discuss several establishment methods of heart valve constitutive models. We also discuss the development trend of heart valve mechanics.
Objective To evaluate the quality of anticoagulant therapy in patients with mechanical prosthetic valve replacement during early period through time in therapeutic range(TTR) and fraction of time in therapeutic range(FTTR), and to provide an objective evidence for further improving quality of anticoagulant therapy. Methods All the patients were followed and registered in hospital and at outpatient clinic from July 2012 through April 2014, with a maximum of 6 months after surgery. Targeted international normalized rate (INR) was 1.60 to 2.20, acceptable INR was 1.50 to 2.30. And warfarin weekly dosage adjustment was used as the strategy of anticoagulation management. Adjusting the warfarin dosage when INR was beyond acceptable INR. Events of bleeding, thrombogenesis and thromboembolism, TTR and FTTR of these patients during the follow-up were collected to evaluate quality of anticoagulant therapy in these patients. Results A total 477 patients and 2 755 reports of INR values were included for data analysis. The follow-up time was 78 918 days. Values of INR varied from 0.92 to 7.72(1.83±0.64). Required weekly doses of warfarin in target INR and acceptable INR were 5.00–35.00(18.15±3.99) mg/week and 5.00–39.38(18.29±4.08) mg/week. TTR of target INR and acceptable INR was 36.85%(27 079.5 d/78 918.0 d) and 49.84% (39 331.5 d/78 918.0 d), respectively. FTTR of target INR and acceptable INR was 37.31% (1 028 times/2 755 times), 50.01% (1 378 times/2 755 times), respectively. TTR of target INR and acceptable INR was 46.04%(3 902.5 d/8 475.5 d), 59.49%(5 042 d/8 475.5 d) when the patients’ follow-up was up to six months and FTTR of target INR and acceptable INR value of these patients was 46.81%(206 times/440 times), 60.45%(266 times/440 times). During the follow-up, there were 3 thromboembolism events, 1 transient physical abnormal activity, and 1 thrombogenesis in the left atrium, and there was no bleeding and death events. Conclusion The strategy of anticoagulation management used in our study is reasonable. In order to further improve the patients’ quality of anticoagulant therapy, it is necessary to start anticoagulation after operation as soon as possible, to strengthen the education of patients with anticoagulant knowledge and to increase INR test frequency properly.
Objective To observe whether Cyclo-RGDfK (Arg-Gly-Asp-D-Phe-Lys) could enhance the adhesion of myofibroblast to decellularized scaffolds and upregulate the expression of Integrin αVβ3 gene. Methods Myofibroblast from the rat thoracic aorta was acquired by primary cell culture. The expression of Vimentin and α-smooth muscle actin(α-SMA) has been detected by immunoflurescent labeling. Decellularized valves have been randomly divided into three groups (each n=7). Group A (blank control): valves do not receive any pretreatment; Group B: valves reacted with linking agent NEthylN(3dimethylaminopropyl)carbodiimide hydrochloride (EDC) for 36 hours before being seeded; Experimental group: Cyclo-RGD peptide has been covalently immobilized onto the surface of scaffolds by linking agent EDC. The fifth generation of myofibroblast has been planted on the scaffolds of each group. The adhesion of myofibroblast to the scaffolds was evaluated by HE staining and electron scanning microscope. The expression of Integrin αVβ3 was quantified by halfquantitative reverse transcriptionpolymerase china reaction (RT-PCR). Results We can see that myofibroblast has exhibited b positive staining for Vimentin and α-SMA. Besides, it has been shown that the expression of Integrin αVβ3 was much higher in the experimental group than that of the group A and group B(Plt;0.05). There was no statistically difference in group A and group B (P=0.900). Conclusion RGD pretreatment does enhance the adhesive efficiency of seeding cells to the scaffolds and this effect may be related to the upregulation of Integrin αVβ3.