Transcatheter aortic valve replacement has revolutionized the management of aortic stenosis and become the gold standard for the treatment of symptomatic and severe aortic valve stenosis in elderly patients. With the improvement in design and materials, newer generation transcatheter aortic valve prostheses had overcome the limitations of early-generation devices that were susceptible to paravalvular leak, atrioventricular block and vascular complications, to a certain extent. This review provides an update on the latest advances in transcatheter aortic valve prostheses.
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.
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.
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.
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 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.
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.
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.
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.
The management of women with mechanical heart valves during pregnancy remains difficult and controversial. The selection of prosthetic heart valve, management during pregnancy and delivery period, guidelines and anticoagulation strategy used in patients with a mechanical heart valve in China are summarized in this review.