VALVE REPLACEMENT WITH BILEAFLET HEART VALVE PROSTHESIS: FOLLOW-UP OF 170 CASES

From Feb. 1989 to May 1996, 170 patients underwent valve replacement with bileaflet heart valve prosthesis. There were 13 early deaths (mortality of 7-65% ), and 6 late deaths. The Preoperative cardiac function (NYHA) was grade Ⅱ in 96 cases, Ⅳ in 35 cases and Ⅲ to Ⅳ in 77. 1%.Follow-up of the survivors from 3 to 87 (average 39) months showed that most of them could do light and moderate physical labor, and cardiac function was restored to grade Ⅰ～ Ⅱ in 96. 4%. Anti-coagulating bleeding is a common complicaion. However, severe embolism and valve dysfunction had not been found- The authors analysed the causes of death and follow-up data, then emphasized that it was necessary that valve replacement be performed as early as possible, and bileaflet heart valve substitute was the best choice. Furthermore, therapy of little dose anti-coagulating drug(warfarin 1.5～3- 0mg/d) is safe and dependable to most of the patients.

Self-Care Practice of Patients with Mechanical Heart Valve Prosthesis Accompanied in Nursing Consultation

The objective was to evaluate the practice of self-care of patients with mechanical heart valve prosthesis. A descriptive, cross-sectional study developed in two outpatient valvopathies of teaching hospitals of Fortaleza/CE, from October 2013 to January 2014. The sample consisted of 127 patients with mechanical heart valve prosthesis. It was held an interview using instrument based on the Theory of Orem’s Self-Care and Brazilian Guidelines for Valvular Heart Diseases. The data were presented in tables and charts. Results: Universal self-care practices of larger adhesion: body hygiene (97.6% washed-haired, daily-bath 92.1%);oral hygiene (brushing teeth before sleeping, 87.4%);fluid intake (drinking-water 95.2%);food intake (salt intake ≤ 2 g/day, 92.1%, fruit and vegetable consumption 79.5%);intestinal eliminations (without blood or mucus—96%, non-parasitic 94.4%);urinary elimination (no blood nor pus-96.8%, urination 4 to 6 times a day, 96%). As self-care developmental requirements predominated: never used illegal drugs, tobacco, alcohol, or stopped at the discovery of the disease (70%). As self-care health deviation requirements we have: making use of certain medication at the right dose (95.2%);attending medical appointments (cardiologist—92.1%;nursing—84.2%);INR control (identifies signs of bleeding— 85.8%). We conclude that patients did not perform all recommended self-care practices, being necessary to establish strategies to reduce the self-care deficit.

The Application Effect of Predictive Nursing on Cardiopulmonary Rehabilitation of Patients Undergoing Heart Valve Surgery with Extracorporeal Circulation

Objective:To evaluate the application effect of predictive nursing on patients undergoing heart valve surgery with extracorporeal circulation(ECC).Methods:92 ECC patients admitted to the hospital between July 2021 and July 2023 were selected and grouped by random number table method;the observation group practiced predictive nursing,while the reference group practiced conventional nursing.The cardiopulmonary rehabilitation and other indexes were compared between the groups.Results:The postoperative rehabilitation time of the observation group was shorter than that of the reference group,the treatment compliance was higher than that of the reference group,the cardiopulmonary function indexes were all better than that of the reference group,and the complication rate was lower than that of the reference group(P<0.05).Conclusion:The implementation of predictive nursing for ECC patients can promote postoperative rehabilitation,improve patients’treatment compliance,and enhance the cardiopulmonary rehabilitation effect,and nursing safety is high.

Trilayer anisotropic structure versus randomly oriented structure in heart valve leaflet tissue engineering

It has been hypothesized that leaflet substrates with a trilayer structure and anisotropicmechanical properties could be useful for the production of functional and long-lasting tissue-engineered leaflets.To investigate the influence of the anisotropic structural and mechanical characteristics of a substrate on cells,in this study,we electrospun trilayer anisotropic fibrous substrates and randomly oriented isotropic fibrous substrates(used as controls)from polycaprolactone polymers.Consequently,the random substrates had higher radial and lower circumferential tensile properties than the trilayer substrates;however,they had similar flexural properties.Porcine valvular interstitial cells cultured on both substrates produced random and trilayer cell-cultured constructs,respectively.The trilayer cell-cultured constructs had more anisotropic mechanical properties,17%higher cellular proliferation,14%more extracellular matrix(i.e.,collagen and glycosaminoglycan)production,and superior gene and protein expression,suggesting that more cells were in a growth state in the trilayer constructs than in the random constructs.Furthermore,the random and radial layers of the trilayer constructs had more vimentin,collagen,transforming growth factor-beta 1(TGF-ß1),transforming growth factor-beta 3(TGF-ß3)gene expression than in the circumferential layer of the constructs.This study verifies that the differences in structural,tensile,and anisotropic properties of the trilayer and random substrates influence the characteristics of the cells and ECM in the constructs.

Imaging of pannus formation in patients with mechanical heart valves

Patient-prosthesis mismatch(PPM) should be recognized in patients with elevated transprosthetic gradients but without leaflet immobility, since the treatment strategy may differ in either etiology. However, thrombus and/or pannus formation should be excluded before a diagnosis of PPM is made. Particularly, pannus formation may not be diagnosed with 2-dimensional transesophageal echocardiography. Electrocardiographically gated 64-section multidetector computed tomography(MDCT) may be a promising tool in diagnosing or excluding pannus formation. Our report underlines the utility of MDCT in this regard and also emphasizes the importance of recognition of PPM as a differential diagnosis in such patients.

Observations on Cardiac Output in Animal Experiments and Clinical Application of Jiuling Bileaflet Mechanical Valve Prosthesis

Objective： To observe the cardiac output （CO） in animals and patients undergone valve replacement with Jiuling bileaflet mechanical valve prosthesis. Methods： 1. Animal experiments： 6 sheep that subjected to mitral replacement with a 2 I-ram-valve prosthesis were measured by open cardiac catheterization intraoperatively. Echocardiographic and open cardiac catheterization under dobutamine stress were performed on 2 sheep survival for 30 months post-operation.2. Patient measurements： CO of 14 cases of aortic valve and 10 cases of mitral valve was measured by open cardiac catheterization,and after 12 months,it was measured by echocardiography. Results： 1. Animal experiments： The mean CO of 6 sheep was 2.5 L/min intraoperatively by catheterization, and that of 2 sheep survival for 30 months post-implant was 3.0 L/min by echocardiography and 2.9 L/min by catheterization, respectively. 2. Patient measurements： The mean cardiac index of 4 patients with 21 mm valve replacement was （2.55 ± 0.27） L/min/m^2by catheterization, and was （2.84 ± 0.13） L/min/m^2 by echocardiography after 12 months. Conclusion： This study demonstrates that cardiac function on animals and patients return to normal activity after undergone the valve replacement, and the newly valve prosthesis shows excellent hemodynamic performance.

Application of Decellularized Scaffold Combined with Loaded Nanoparticles for Heart Valve Tissue Engineering in vitro

The purpose of this study was to fabricate decelluarized valve scaffold modified with polyethylene glycol nanoparticles loaded with transforming growth factor-β1（TGF-β1）,by which to improve the extracellular matrix microenvironment for heart valve tissue engineering in vitro.Polyethylene glycol nanoparticles were obtained by an emulsion-crosslinking method,and their morphology was observed under a scanning electron microscope.Decelluarized valve scaffolds,prepared by using trypsinase and TritonX-100,were modified with nanoparticles by carbodiimide,and then TGF-β1 was loaded into them by adsorption.The TGF-β1 delivery of the fabricated scaffold was measured by asing enzyme-linked immunosorbent assay.Whether unseeded or reseeded with myofibroblast from rats,the morphologic,biochemical and biomechanical characteristics of hybrid scaffolds were tested and compared with decelluarized scaffolds under the same conditions.The enzyme-linked immunosorbent assay revealed a typical delivery of nanoparticles.The morphologic observations and biological data analysis indicated that fabricated scaffolds possessed advantageous biocompatibility and biomechanical property beyond decelluarized scaffolds.Altogether this study proved that it was feasible to fabricate the hybrid scaffold and effective to improve extracellular matrix microenvironment,which is beneficial for an application in heart valve tissue engineering.

Effect of L-carnitine on Cardiomyocyte Apoptosis and Cardiac Function in Patients Undergoing Heart Valve Replacement Operation

Summary： The effects of L-carnitine, as an ingredient of cardioplegia solution, on cardiac function and cardiomyocyte apoptosis in patients undergoing heart valve replacement operation were investigated. Twenty-three cases undergoing heart valve replacement with cardiopulmonary bypass （CPB） were randomly allocated into two groups： L-carnitine group （n=12, 12 g/L L-carnitine was put in the ST. Thomas cardioplegia） and control group （n=11, identical to the L-carnitine group except that normal saline was administered instead of L-carnitine）. Serum cardial troponin I （cTnI） levels, the left ventricular ejection fraction （LVEF）, and cardiac index （CI） were measured perioperatively. A bit of myocardial tissue obtained from right atria was taken before CPB and by the end of intracardiac procedure to undergo electron microscopy examination and estimate apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling （TUNEL）. From the end of CPB to 3 days after operation, the serum levels of cTnI in the L-carnitine group was significantly lower than that in the control group （P〈0.05）. Heart color ultrasonogram showed that the CI index and LVEF at 7th day postoperatively in the L-carnitine group were significantly higher than in the control group （P〈0.05）. Compared to the control group, L-carnitine significantly alleviated the morphologic changes of cardiac muscle cells （electron microscopy examination） and decreased the amounts of apoptotic cardiac muscle cells （TUNEL）. Furthermore, the dosage of vasoactive drugs used after operation was significantly less in the L-carnitine group （P〈0.01）. It was concluded that L-carnitine cardioplegia solution could improve cardiac function in patients undergoing heart valve replacement operation and alleviate CPB-mediated apoptosis of cardiac muscle cells.

Anticoagulation early after mechanical heart valve replacement

Objective： To explore the changes of coagulation activity and the characters of anticoagulation early after mechanical heart valve replacement. Methods： All patients only took warfarin orally for anticoagulation. The predicted international normalized ratio （INR） was 1.5 to 2.0. Several coagulation markers were monitored early after valve replacement. Complications associated with anticoagulation were recorded and analyzed. The patients were divided into three groups based on the number and position of mechanical valve prothesis, including group M （mitral valve replacement）, group A （aortic valve replacement） and group D （mitral and aortic valve replacement）.Comparison was made between the three groups. Results： Three events of mild cerebral embolism and five events of mild bleeding occurred during the early postoperative period. One patient suffered from mild cerebral embolism on the 4th day after operation, accompanied by large volume of pericardial drainage. Two patients with bleeding had lower INRs than predicted range. However, INR in one patient with mild cerebral embolism was in the predicted range. There was no significant difference in thrombo time （TT）, activated partial thromboplastin time （APTT） and 1NR on the 3rd day after operation compared to those before operation; meanwhile, plasma fibrinogen （FIB） concentration was higher than that before operation （P〈0.05）. 1NR had no significant changes on the 2nd day after the beginning of anticoagulation compared to that before operation; however, 1NR was significantly elevated on the 4th day （P〈0.05）. Warfarin doses and INRs were similar among the three groups, but FIB concentrations in plasma were higher in groups M and D than in group A （P〈0.01）. Conclusion： Hypercoagulabale state exists early after mechanical heart valve replacement. When anticoagulation begins is determined by the change of coagulation markers, not by the volume of chest or pericardial drainage. INR can not accurately reflect the coagulation state sometimes, especially during the first 3 days after anticoagulation. The number and position of mechanical valve prothesis could affect coagulation state. Therefore, anticoagulation therapy should be regulated accordingly.

Univariate Risk Factors for Prolonged Mechanical Ventilation in Patients Undergoing Prosthetic Heart Valves Replacement Surgery

Data from 736 patients undergoing prosthetic heart valve replacement surgery and concomitant surgery （combined surgery） from January 1998 to January 2004 at Union Hospital were retrospectively reviewed. Univariate logistic regression analyses were conducted to identity risk factors for prolonged mechanical ventilation. The results showed that prolonged cardiopulmonary bypass duration, prolonged aortic cross clamp time and low ejection fraction less than 50 percent （50 %） were found to be independent predictors for prolonged mechanical ventilation. Meanwhile age, weight, and preoperative hospital stay （days） were not found to be associated with prolonged mechanical ventilation. It was concluded that. for age and weight, this might be due to the lower number of old age patients （70 years and above） included in our study and genetic body structure of majority Chinese population that favor them to be in normal weight, respectively.

Development of Biofunctionalized Cellulose Acetate Nanoscaffolds for Heart Valve Tissue Engineering

Currently-used mechanical and biological heart valve prostheses have a satisfactory short-term performance, but may exhibit several major drawbacks on the long-term. Mechanical prostheses, based on carbon, metallic and polymeric components, require permanent anticoagulation treatment, and their usage often leads to adverse reactions, e.g. thromboembolic complications and endocarditis. In recent years, there is a need for a heart valve prosthesis that can grow, repair and remodel. The concept of tissue engineering offers good prospects into the development of such a device. An ideal scaffold should mimic the structural and purposeful profile of materials found in the natural extracellular matrix (ECM) architecture. The goal of this study was to develop cellulose acetate scaffolds (CA) for valve tissue regeneration. After their thorough physicochemical and biological characterization, a biofunctionalization process was made to increase the cell proliferation. Especially, the surface of scaffolds was amplified with functional molecules, such as RGD peptides (Arg-Gly-Asp) and YIGSRG laminins (Tyrosine-Isoleucine-Glycine-Serine-Arginine-Glycine) which immobilized through biotin-streptavidin bond, the strongest non-covalent bond in nature. Last step was to successfully coat an aortic metallic valve with CA biofunctionallized nanoscaffolds and cultivate cells in order to create an anatomical structure comparable to the native valve. Promising results have been obtained with CA-based nanoscaffolds. We found that cells grown successfully on the biofunctionalized valve surface thereby scaffolds that resemble the native tissues, elaborated with bioactive factors such as RGD peptides and laminins not only make the valve’s surface biocompatible but also they could promote endothyliazation of cardiac valves causing an anti-coagulant effect

Fabrication of a Novel Hybrid Scaffold for Tissue Engineered Heart Valve

The aim of this study was to fabricate biomatrix/polymer hybrid scaffolds using an electrospinning technique. Then tissue engineered heart valves were engineered by seeding mesenchymal stromal cells （MSCs） onto the scaffolds. The effects of the hybrid scaffolds on the proliferation of seed cells, formation of extracellular matrix and mechanical properties of tissue engineered heart valves were investigated. MSCs were obtained from rats. Porcine aortic heart valves were decellularized, coated with poly（3-hydroxybutyrate-co-4-hydroxybutyrate） using an electrospinning technique, and reseeded and cultured over a time period of 14 days. In control group, the decellularized valve scaffolds were reseeded and cultured over an equivalent time period. Specimens of each group were examined histologically （hematoxylin-eosin [HE] staining, immunohistostaining, and scanning electron microscopy）, biochemically （DNA and 4-hydroxyproline） and mechanically. The results showed that recellularization was comparable to the specimens of hybrid scaffolds and controls. The specimens of hybrid scaffolds and controls revealed comparable amounts of cell mass and 4-hydroxyproline （P〉0.05）. However, the specimens of hybrid scaffolds showed a significant increase in mechanical strength, compared to the controls （P〈0.05）. This study demonstrated the superiority of the hybrid scaffolds to increase the mechanical strength of tissue engineered heart valves. And compared to the decellularized valve scaffolds, the hybrid scaffolds showed similar effects on the proliferation of MSCs and formation of extracellular matrix. It was believed that the hybrid scaffolds could be used for the construction of tissue engineered heart valves.

Pathogenic Mineralization of Calcium Phosphate on Human Heart Valves

When calcium phosphate forms in soft tissues such as blood vessels and heart valves, it causes disease. The abnormal formation of calcium phosphate is called pathogenic mineralization or pathogenic calcification. Cases of rheumatic heart disease （RHD） always occur with fibrotic and calcified tissue of heart valve. In this article, samples taken from calcified human heart wdves were studied. The characterization was performend by scanning electronic microscope, X-ray Diffraction and transmission electron microscopy with selective diffraction patterns. It is found for the first time that calcium phosphate grains existing in the calcified human heart valves contain octacalcium phosphate （ OCP ）.

Observations on Durability of a Pyrolytic Carbon Bileaflet Mechanical Heart Valve

This study aims to observe the durability of a pyrolytic carbon bileaflet mechanical valve prosthesis. The mechanical valves prosthesis was tested in vitro by the durability test instrument of valve prosthesis. Then in vivo, the durability of the implanted valves was observed with animal experiments and elinieal application. In the impact test for 5 min and durability test of 380 million eyeles in vitro, there was no the phenomenon of flyer, perforation and fracture observed, as well as no wear or pit found on the surface of valve leaflets. The valve leaflets could normally be turned on or off. The weight of the valve was（1.0031 ± 0.0004） g for 23 mm and（1.6003 ± 0.0002） g for 27 mm. The hydrodynamies test demonstrated that the valve prosthesis had still exeellent hemodynamic performance after the durability test. The animal autopsy showed that the valve leaflets could normally be turned on or off, and no wear was found. By follow-up of 62 patients implanted the valves, all patients had long-terms survival, no complication caused by valve was found. The age of the longest survival was more than 10 years. This study demonstrates that the new meehanieal valve prosthesis have excellent durable performance.

Very late transcatheter heart valve thrombosis

We describe a case of very late transcatheter heart valve(THV) thrombosis of a first-generation SAPIEN prosthesis(Edwards Lifesciences, Irvine, CA) implanted in a 64-yearold woman with severe symptomatic aortic stenosis. More than 54 mo after implantation, she presented with severe symptomatic prosthesis dysfunction(stenosis) which was successfully treated with oral anticoagulation. To our knowledge, this is the tardiest case of THV thrombosis ever reported. This case should increase clinical awareness for THV thrombosis even beyond the first two-year period following implantation.

Body-temperature circadian rhythm in 67 patients after heart valve replacement surgery secondary to valvular heart disease

Purpose:Patient body temperature was monitored after cardiac valve replacement,in order to explore the characteristics of body-temperature circadian rhythm and the factors influencing that rhythm.Methods:A cohort of 67 patients who received cardiac valve replacement in a Fuzhou,Fujian province,China,general hospital underwent temperature measurements and analysis(by cosine curve)of their body-temperature circadian rhythm.A biological rhythm model was established through principal component analysis and evaluation of biological rhythm features.Multiple circadian parameters were included through linear regression analysis.Results:Patients’temperature after cardiac valve replacement exhibited circadian characteristics(p<0.05),among which the scores of temperature mesor,amplitude,and acrophase were respectively(37.61
0.08),(0.10
0.09),and33(e355,e119).Body-temperature rhythms were influenced by both gender and cardiopulmonary bypass time(p<0.05).Conclusion:Although some patients’circadian characteristics disappeared after cardiac valve replacement,circadian rhythms remained intact for most patients.Measures that were found to mitigate body-temperature circadian rhythm disruption included building a natural rhythm of light/darkness and decreasing cardiopulmonary bypass time.

In vitro calcification studies on bioprosthetic and decellularized heart valves under quasi-physiological flow conditions

The lifespan of biological heart valve prostheses available in the market is limited due to structural alterations caused by calcium phosphate deposits formed from blood plasma in contact with the tissues.The objective of this work is to present a comparative methodology for the investigation of the formation of calcium phosphate deposits on bioprosthetic and tissue-engineered scaffolds in vitro and the influence of mechanical forces on tissue mineralization.Based on earlier investigations on biological mineralization at constant supersaturation,a circulatory loop simulating dynamic blood flow and physiological pressure conditions was developed.The system was appropriately adapted to evaluate the calcification potential of decellularized(DCV)and glutaraldehyde-fixed(GAV)porcine aortic valves.Results indicated that DCV calcified at higher,statistically nonsignificant,rates in comparison with GAV.This difference was attributed to the tissue surface modifications and cell debris leftovers from the decellularization process.Morphological analysis of the solids deposited after 20 h by scanning electron microscopy in combination with chemical microanalysis electron-dispersive spectroscopy identified the solid formed as octacalcium phosphate(Ca8(PO4)6H2·5H2O,OCP).OCP crystallites were preferentially deposited in high mechanical stress areas of the test tissues.Moreover,GAV tissues developed a significant transvalvular pressure gradient increase past 36 h with a calcium deposition distribution similar to the one found in explanted prostheses.In conclusion,the presented in vitro circulatory model serves as a valuable prescreening methodology for the investigation of the calcification process of bioprosthetic and tissue-engineered valves under physiological mechanical load.

Role of thrombus precursor protein in assessment of anticoagulation in patients with atrial fibrillation after mechanical heart valve replacement

Objective: To explore the role of thrombus precursor protein (TpP) in assessment of anticoagulation and predict the risk of thromboembolism in the patients with atrial fibrillation (AF) after mechanical heart valve replacement. Methods: TpP plasma concentration and international normalization ratio (INR) were measured in 45 patients with atrial fibrillation and 45 patients with sinus rhythm both after mechanical heart valve replacement. Twenty patients with non valvular heart diseases were selected as the control. Furthermore, the patients with AF were divided into groups based on different TpP plasma concentration and TpP plasma concentration and INR were analyzed. Results: After mechanical heart valve replacement, those with AF had higher TpP plasma concentration than those with sinus rhythm. It was found that discordancy existed between INR and TpP plasma concentration in the patients with AF. There were 28 AF patients with TpP plasma concentration lower than 6 μg/ml and without bleeding, who might be at the optimal anticoagulant state. The 95% confidence of the mean INR value was 1.90-2.30 in these patients and TpP plasma concentration was between 2.84-5.74 μg/ml. Conclusion: Patients with AF might face higher risk of thromboembolism after mechanical valve replacement; INR between 1.90-2.30 and TpP plasma concentration between 2.84-6 μg/ml might be the optimal anticoagulant range for patients with AF after mechanical valve replacement.

Application of modified polyethylene glycol hydrogels in the construction of tissue engineered heart valve

To enhance the adhesion of seeding-cells to the biomaterial scaffolds, the PEG-hydrogels were modified. Porcine aortic valves were decellularized with Triton X-100 and trypsin. The cells were encapsulated into the PEG-hydrogels to complete the process of the cells attaching to the acellular porcine aortic valves. Herein, the autologous mesenchymal stem cells （MSCs） of goats were selected as the seeding-cells and the tendency of MSCs toward differentiation was observed when the single semilunar TEHV had been implanted into their abdominal aortas. Furthermore, VEGF, TGF-β1, and the cell adhesive peptide motif RGD were incorporated. Light and electron microscopy observations were performed. Analysis of modified PEG-hydrogels TEHV＇s （PEG-TEHV） tensile strength, and the ratio of reendothelial and mural thrombosis revealed much better improvement than the naked acellular porcine aortic valve （NAPAV）. The data illustrated the critical importance of MSC differentiation into endothelial and myofibroblast for remodeling into native tissue. Our results indicate that it is feasible to reconstruct TEHV efficiently by combining modified PEG-hydrogels with acellular biomaterial scaffold andautologous MSCs cells.

Effect of Psychological Nursing on the Mental State and Quality of Life of Patients After Heart Valve Replacement for Rheumatic Heart Disease

Objective:To explore the effect of psychological nursing on the mental state and quality of life of patients after heart valve replacement for rheumatic heart disease.Methods:Seventy-four patients with rheumatic heart disease that underwent heart valve replacement in Zhenjiang First People's Hospital from January 2017 to May 2020 were selected as the research subjects.Thirty-seven patients that were treated from January 2017 to September 2018 were included in the control group.Routine care was provided for the patients in the control group.From October 2018 to May 2020,the Department of Cardiothoracic Surgery improved their preoperative and postoperative psychological care.Thirty-seven patients that were treated during this period were included in the research group.The research group received psychological nursing care in addition to routine care.The efiects of different nursing modes on the quality of life and postoperative mental state of the patients were determined.Results:The scores for depression,anxiety,somatization,and compulsion in the research group were significantly lower than those in the control group(p<0.05);the scores for the quality of life of patients in the research group were significantly higher than those in the control group(p<0.05).Conclusions:Strengthening psychological nursing for patients with rheumatic heart disease is helpful to improve their quality of life and mental state after heart valve replacement.