Transcatheter aortic valve replacement (TAVR) for aortic stenosis has been confirmed to be safe and efficient, and its status has gradually increased with the continuous updating of guidelines. But for severe pure aortic valve regurgitation, it has long been considered a relative contraindication to TAVR. However, many elderly, high-risk patients with pure aortic regurgitation have also been treated with TAVR and prognosis was improved through off-label use of transcatheter heart valves due to contraindications to surgery or intolerance. But because of the complexity and challenging anatomic features, high technical requirements, limited device success rate, high rate of complications, and lack of randomized controlled studies to confirm its safety and efficacy, TAVR treatment of pure aortic regurgitation has been evolving in a debate. In recent years, with the application of new-generation valves and an increasing number of studies, some new insights have been gained regarding TAVR for severe aortic regurgitation, and this article will review the progress of research on TAVR for severe pure aortic regurgitation.
ObjectiveTo describe the status of quality of life (QOL) and self-management behavior in patients following mechanical heart valve replacement, and explore the relationship between QOL and self-management behavior.
MethodsConvenient sampling was used to recruit 352 patients following mechanical heart valve replacement in a high-level hospital in Chengdu between January 2011 and June 2012. General information questionnaire, MOS SF-36 scales, and self-management behavior questionnaire were used to collect data. T-test was used to analyze the difference between patients and normal people. And correlation analysis was used to see the correlation between QOL and self-management.
ResultsFor MOS SF-36 scale results in patients within one year after surgery, physical functioning (PF) score was 73.44±15.11, role-physical (RP) was 49.52±39.17, body pain (BP) was 63.13±17.93, general health (GH) was 58.85±14.88, vitality (VT) was 63.54±18.10, social functioning (SF) was 76.67±17.40, role-emotional (RE) was 64.96±41.37, and mental health (MH) was 72.76±17.40. All these scores of the patients were significantly lower than the norm of Sichuan Province (P<0.05) except the dimension of mental health. For patients one year or more after surgery, PF score was 76.53±14.41, RP 58.44±39.21, BP 68.16±18.26, GH 61.39±13.57, VT 68.47±16.37, SF 79.79±19.34, RE 72.94±37.29, and MH 75.87±14.70, among which PF, RE, BP and GH scores were lower than the norm (P<0.05). The average total score of self-management behavior was 143.21±20.63. QOL and self-management behavior were positively correlated.
ConclusionThere is still a gap between patients following mechanical heart valve replacement and normal people in terms of quality of life. Patients' self-management behavior is positively correlated with the quality of life. Good self-management behavior contributes to the improvement of QOL.
ObjectiveTo study the hemocompatibility of bioprosthetic heart valve materials respectively based on glutaraldehyde and non-glutaraldehyde treatment. MethodsFresh bovine pericardium was treated with glutaraldehyde or non-glutaraldehyde after adipose tissue was removed. To evaluate the hemocompatibility of the two bioprosthetic heart valve materials, hemolysis test, in vitro fibrinogen adsorption experiment, platelet adhesion experiment, thrombin-antithrombin complex (TAT) test, complement activation assay and ex vivo circulation experiment were performed. ResultsThe hemolysis test results demonstrated that both of the materials showed hemolytic rates lower than 5%. The results of TAT test and complement activation assay showed no statistical differences among the two materials and the blank control group. Compared to the bioprosthetic heart valve materials with glutaraldehyde-based treatment, the materials with non-glutaraldehyde-based treatment showed significantly decreased fibrinogen adsorption, platelet adhesion and thrombosis. ConclusionCompared to the bioprosthetic heart valve materials with glutaraldehyde-based treatment, the materials with non-glutaraldehyde-based treatment show better hemocompatibility.
Objective To explore the role of thrombus precursor protein(TPP) in the monitoring of anticoagulation in the patients with atrial fibrillation (Af) after mechanical heart valve replacement, and suggest the reasonable anticoagulant range. Methods Ninety patients were divided into Af group (n=45), sinus rhythm group (SR group, n=45), and control group (20 patients with non-valvular heart diseases), according to whether Af exist after mitral valve replacement. TPP concentrations and International Normalized Ratio(INR) in the anticoagulant patients were analyzed. Results In patients after mechanical mitral valve replacement, plasma TPP concentrations in both SR group and Af group were lower than that in control group (Plt;0.05,0.01), their INR value were higher than that in control group (Plt;0.01), and Af group had higher plasma TPP concentrations than that in SR group((Plt;)0.05). It was found that there existed contradictions between INR and plasma TPP concentrations in Af group. There were 28 patients with plasma TPP concentrations below 6 μg/ml and without spontaneous bleeding complications in the group with Af, who might be at the optimal anticoagulant status. Their 95% confidence of INR value was 1.90-2.30 and their plasma TPP concentration was 4.29±0.75μg/ml. Conclusion Patients with Af after mechanical heart valve replacement might have higher risk of thromboembolism, INR between 1.90 - 2.30 and plasma TPP concentration between 2.84-6.00 μg/ml might be the optimal anticoagulant therapeutic range.
Objective To develop a tissue engineering scaffold by using 4arm branched polyethylene glycol-VS (PEG-VS) crosslinked with decellularized valved conduits (DVC), and to research on its mechanical and biological functions. Methods The valved aortic conduits of rabbits were taken and decellularized by trypsin method and then were crosslinked with 4arm branched PEG-VS to construct the composite scaffolds (CS). The functions of decellularized valved conduits and the composite scaffolds were tested by mechanics test system. Thirty New Zealand white rabbits were equally and randomly assigned to one of the three groups: the control group, the DVC group, and the CS group. Valved aortic conduits, decellularized valved conduits and composite scaffoldswere transplanted into the common carotid artery of the abovementioned three groups of rabbits respectively. Twentyeight days after the operation, patency of the transplants was tested by Color Doppler ultrasound; micromorphology and inflammatory infiltration were observed by hematoxylin eosin（HE） staining andscanning electron microscope (SEM)，and endothelialization of composite scaffolds was detected by immunofluorescent staining. Results A series of biomechanical analyses revealed that the composite scaffolds had highly similar mechanical properties as fresh tissue, and had superior elastic modulus (P=3.1×10-9) and tensile strength (P=1.1×10-6) compared with decellularized valved conduits. Color Doppler ultrasound revealed that the graft patency for the CS group was better than the control group (P=0.054) and the DVC group (P=0.019), and the intraaortic thrombosis rate and distortion rate decreased significantly. HE staining and SEM showed that the endothelialization of composite scaffolds in the CS group was significantly higher than the other two groups with the endothelial cells evenly distributed on the scaffolds. The [CM(159mm]immunofluorescent staining indicated that the positive rate of the endothelial cell marker CD34 was higher than the other two groups. Conclusion The composite scaffolds using 4arm branched PEGVS crosslinked with DVC have great mechanical and biological properties.
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.
ObjectiveTo evaluate the reasonableness of anticoagulation management strategy in patients after mechanical heart valve replacement.
MethodsAll patients were followed and registered continually at outpatient clinic from July 2011 to February 2013, with a minimum of 6 months after surgery. Targeted international normalized rate (INR) 1.60 to 2.20 and warfarin weekly dosage adjustment were used as the strategy of anticoagulation management. Except bleeding, thrombogenesis and thromboembolism, time in therapeutic range (TTR) and fraction of TTR (FTTR) were adopted to evaluate the quality of anticoagulation management.
ResultsA total 1 442 patients and 6 461 INR values were included for data analysis. The patients had a mean age of 48.2±10.6 years (14-80 years) and the following up time were 6 to 180 months (39.2±37.4 months) after surgery. Of these patients, 1 043 (72.3%) was female and 399 (27.7%) was male. INR values varied from 0.90-8.39 (1.85±0.49) and required weekly doses of warfarin were 2.50-61.25 (20.89±6.93 mg). TTR of target INR and acceptable INR were 51.1% (156 640.5 days/306 415.0 days), 64.9% (198 856.0 days/306 415.0 days), respectively. FTTR of target INR and acceptable INR were 49.4% (3 193 times/6 461 times), 62.6% (4 047 times/6 461 times). There were 8 major bleeding events, 7 mild bleeding events, 2 thromboembolism events, and 2 thrombogenesis in the left atrium.
ConclusionIt is reasonable to use target INR 1.60-2.20 and warfarin weekly dosage adjustment for patients after mechanical heart valve replacement.
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 Using Amplex red fluorometric assay to detect the lysyl oxidase (LOX) enzyme activity in tissue engineered heart valve (TEHV). Methods Porcine aortic valves were decellularized with trypsin+ethylene diaminetetraacetic acid(EDTA), TritonX-100, and RNaseⅠ＋DNaseⅠ, then they were seeded by myo-fibroblasts that harvested from rats. Then they were fed with Dulbecco’s modified Eagle medium (DMEM) which contained high glucose for 27 days, they were fed with phenol red-free and serumfree DMEM for 24 hours, and the medium was harvested and used for LOX enzyme activity assays with the Amplex red fluorometric assay. And reverse transcription-polymerase chain reaction (RT-PCR) technique was used to analyze the expression of LOXmRNA in TEHV. Results All the samples produced measurable amounts of active LOX enzyme. The fluorescence units were 45.60±1.66, and the corresponding concentration of LOX enzyme were 0.123±0.003μg/ml. At the same time, all the samples expressed LOXmRNA. The expression of LOXmRNA was corresponding to the results of the Amplex red fluorometric assay. Conclusion It is feasible to detect the LOX enzyme activity in TEHV with the Amplex red fluorometric assay. And this assay gives a way to reflect that LOX plays an important role in collagen cross-linking of extracellar matrix in TEHV.
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.
