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 summarize the monitoring experiences of blood glucose for patients with rheumatic heart disease combined with diabetes, in order to prevent postoperative complications caused by abnormal blood sugar, relieve pain and promote rehabilitation. MethodsWe reviewed the medical records of the patients with diabetes after heart valve replacement who were admitted to our department from April 2011 to March 2012. Eighty patients were randomly divided into observation group and control group with 40 in each group. Patients in the control group received conventional treatment with subcutaneous insulin injection, while the observation group patients were treated with intravenous insulin pump, and the dose of insulin was adjusted depending on blood glucose levels. Then we compared the postoperative changes in blood glucose level and complications between the two groups. ResultsThe insulin dose, the time of reaching target blood glucose levels, hospital stays and postoperative complication rates were significantly lower in the observation group than the control group (P<0.05). During the one-year follow-up after operations, 2 and 4 patients died respectively in the observation group and the control group, and the difference was not significant (χ2=0.180, P=0.670). ConclusionFor patients with diabetes after heart valve replacements, intravenous insulin pump is better than subcutaneous insulin injection. It can prevent complications, shorten hospital stays, reduce financial burden, and promote prognosis and harmonious doctor-patient relationship.
Objective To explore the impact of recombinant human growth hormone （rhGH） on T lymphocyte subsets in patients with rheumatic heart disease during the perioperative period of heart valve replacement. Methods A total of 65 patients with rheumatic valvular heart disease who received heart valve replacement in Department of Cardiothoracic Surgery of Xiangyang Central Hospital from June 1， 2011 to March 31， 2012 were enrolled in this double-blind randomized controlled clinical study. All the patients were divided into 2 groups by random number produced by SAS software：the trial group and the control group. There were 35 patients in the trial group including 19 males and 16 females with their average age of 50.57 years， and 30 patients in the control group including 16 males and 14 females with their average age of 49.87 years. Apart from routine cardiac glycosides， diuretics， glucose-insulin-potassium solution， and postoperative anti-infective therapy， patients in the trial group also received subcutaneously injection of rhGH 5 U （1 ml）daily from 1 day before surgery to 3 days after surgery， and patients in the control group received subcutaneously injection of normal saline 1 ml as placebo. Peripheral venous blood samples were taken in the morning 2 days before surgery and 1 st， 3 rd， 7 th day after surgery respectively. Percentages of CD3+， CD4+， CD8+ were examined timely by flow cytometry and CD4+ /CD8+ ratio was calculated. Results In the control group， percentages of CD3+， CD4+ and CD4+ /CD8+ ratio on the 1st， 3rd， 7th postoperative day were significantly lower than preoperative levels， and percentages of CD8+ on the 1st and 3rd postoperative day were significantly lower than preoperative level （P＜0.05）. In the trial group， percentages of CD3+， CD4+， and CD8+ on the 1st and 3rd postoperative day were significantly lower than preoperative levels（P＜0.05）， while percentages of CD3+， CD4+， and CD8+ on the 7th postoperative day were not statistically different from preoperative levels （P＞0.05）; CD4+ /CD8+ ratio on the 1st postoperative day was significantly lower than preoperative level （P＜0.05）， while CD4+ /CD8+ ratios on the 3rd and 7th postoperative day were not statistically different from preoperative level （P＞0.05）. There was no statistical difference in preoperative T lymphocyte subsets between the trial group and the control group （P＞0.05）. The percentages of CD4+ and CD4+/CD8+ ratio in the trial group were significantly higher than those of the control group on the 1st postoperative day （P＜0.05）， while the percentages of CD3+ and CD4+ and CD4+ /CD8+ratio in the trial group were significantly higher than those of the control group on the 3rd and 7th postoperative day（P＜0.05）. Conclusion Use of rhGH can significantly increase T lymphocyte subsets expression， enhance body cellular immunity， and improve postoperative recovery of patients with rheumatic valvular heart disease during the perioperative period of heart valve replacement.
Objective To observe the intermediate-term outcome and heart function in patients with small aortic root，and to investigate the feasi bility of small size prosthesis. Methods From July 1990 to Jun e 2003, 62 patients underwent 19mm aortic valve prosthesis(19mm group). The resu lts were compaired with other 62 patients receiving larger prosthesis(≥21 mm,21 mm group). Clinical symptoms, signs, electrocardiogram(ECG) and echocardiogr a phy (UCG) were followedup, KaplanMeier survival curve was used for analysis. Results In 19mm group, there were 38 patients with ≥Ⅱ/Ⅵ grade systolic murmur in aortic valve area,18 patients with ECG ST segm ent change and 11 patients with chest pain and/or chest distress. Postoperative cardiac function showed that 33 patients with heart function New York Heart Ass ociation(NYHA) class Ⅱ and 29 patients with NYHA class Ⅲ. Postoperative ECG sh owed in 21mm group,6 patients with ECG ST segment change,3 patients with chest distress and 6 patients with occasional chest pain and there were 48 patients with NYHA class Ⅱ and 14 patients with NYHA class Ⅲ,there was statis tically difference in heart function between two groups（P＝0.020). Th ere was a significant regression of left ventricular end diastolic diameter(LVEDD),left ventricular wall thickness, mass index,and pressure gradients in both groups（P＜0.05）, and left ventricular ejection f raction (LVEF)had a significant increase in patients 5 years after operation tha n that before operation（P＜0.05）, and there was no statistically differenc e in both groups（P＞0.05）. Actual survival at 1,5 years were 93.5%,74 .2% in 19mm group compared with 95.2%,790% in the 21mm valve group, there were no statistically difference in both groups （P=0.231,0.110）. Conc lus ion Patients with 19mm prosthetic aortic valves can experience a satisf actory improvement and get excellent intermediate-term survival.
Abstract: Objective To observe the physical characteristics of decellularized porcine pulmonary valved conduits crosslinked by carbodiimide (EDC). Methods [WTBZ]Twenty porcine pulmonary valved arteries were mobilized on relative asepsis condition. They were cut longitudinally into three samples at the junction position of pulmonary valve (every sample was comprised of a part of the pulmonary conduit wall and the corresponding valve). The samples were randomly divided into three groups by lotdrawing method. Group A was the control group which was made up of the fresh porcine arterial valved conduit samples without any other treatments. Group B was comprised of porcine pulmonary samples decellularized by trypsindetergent digestion. Group Cincluded the decellularized porcine pulmonary samples crosslinked by EDC. We observed the water content, thickness, tensile strength, and shrinkage temperature of all the samples, based on which the physical characeteristics of these samples were analyzed. Results [WTBZ]Complete cellfree-pulmonary conduit matrix was achieved by trypsindetergent digestion. Compared with group A, in group B, the water content of pulmonary wall was significantly higher (P=0.000), while the water content of pulmonary valve was not significantly different; the thickness of pulmonary wall and valve (P=0.000，0.000) and tensile strength of pulmonary wall and valve (Plt;0.01） was significantly lower, while shrinkage temperature was not significantly different. Compared with group B, in group C, the water content of pulmonary wall was significantly lower (P=0.000), while the water content of pulmonary valve, and the thickness of pulmonary wall and valve were not significantly different; the tensile strength of pulmonary wall (Plt;0.01) and valve (P=0.000), and the shrinkage temperature of them (P=0.000, 0.000) were significantly higher. Compared with group A, in group C, the water content of pulmonary wall and valve, and the tensile strength of them were not statistically different, while the thickness of pulmonary wall and valve was significantly lower (P=0.000, 0.000), and the shrinkage temperature of them was significantly higher (P=0.000, 0.000). Conclusion [WTBZ]EDC crosslinking method is available for treating decellularized porcine pulmonary valved conduits in order to enhance its tensile strength, and decrease water content of pulmonary wall.
ObjectiveTo analyze the reason of 45 patients with cardiac valve reoperation and to evaluate the safety of redo heart valve replacement. MethodsWe retrospectively analyzed the clinical data of 45 patients in our hospital between January 2010 and January 2015. There were 45 patients with 14 males and 31 females at an average age of 51.21± 8.36 years. ResultsThree of 45 patients (6.67%) were died after surgery. Mean follow-up was 36 (4-68) months. A total of 42 patients were alive and without reoperation again. The main reasons of heart valve reoperation included lesions of untreated valve, paravalvular leakage, thrombosis associated with valvular dysfunction, bioprosthesis degeneration, endocarditis, valvular lesions after angioplasty. ConclusionTricuspid regurgitation should be treated aggressively when the mitral valve involved in the first operation. Patients received the secondary heart valve replacement is safe and effective. Strict follow-up system should be established and surgical intervention should be taken timely and appropriately.
Objective To investigate the risk factors and the prevention and cure methods of ischemic stroke during low intensity anticoagulation therapy after mechanical heart valve replacement. Methods From March 2004 to July 2008，twentythree patients with ischemic stroke after mechanical heart valve replacement had been researched(ischemic stroke group). One hundred and twenty patients who had undergone mechanical heart valve replacement were randomly chosen in the same period as control group. Gender, age, the dose of warfarin , anticoagulation intensity(INR), INR review interval, left atrial diameter and heart rhythm were compared between the two groups, and the risk factors of ischemic stroke were analyzed by logistic regression analysis. Results (1) Patients in ischemic stroke group all discharged from hospital after treatment, and they were followed up for 1 month-3 years after discharged. All the patients’ neurological complications improved obviously, and no recurrent embolism and severe hemorrhage was found. (2) There was no statistical significance between two groups in gender, age and the dose of warfarin（Pgt;0.05）. (3) Nonconditional logistic regression analysis on influence factors showed that atrial fibrillation（P=0.000）, left atrial enlargement（P=0.002）, low anticoagulation intensity（P=0.012） and longtime INR review interval（P=0.047）were the risk factors of ischemic stroke during low intensity anticoagulation therapy after mechanical heart valve replacement. Conclusions (1)The prognosis of ischemic stroke during low intensity anticoagulation therapy after mechanical heart valve replacement is better than that of intracranial hemorrhage, and the occurrence of ischemic stroke is related to many risk factors. (2)The influences of risk factors should be minimized in order to avoid ischemic stroke. (3) Early low intensity anticoagulation therapy is safe and effective for patients with ischemic stroke after heart valve replacement.
Abstract: Objective To investigate the in vivo effective orifice area (EOA) and whether prosthesispatient mismatch (PPM) is going to happen after 19mm St.Jude Regent valves replacement were performed. Methods Twentythree patients with valvular heart diseases were divided into 2 groups according to aortic annular diameter. 19mm St. Jude Regent valves were replaced in aortic valve place (Regent valve group), and 21mm other doubleleaflet mechanical valves were replaced in aortic place (other valves group). All of the operations were accomplished under cardiopulmonary bypass in West China Hospital. All of the patients were followed up in 3 to 6 months after their surgery processes. Color Doppler echocardiography was used to measure the hemodynamic parameters in their followup. Then left ventricular mass (LV mass), EOA and effective orifice area index (EOAI) etc. were calculated and compared by using SPSS 12.0. Results No cardiac episodes were detected during the perioperative period and 36 months after operation. LVmass reduced in 36 months after operation in both groups. No statistical significance of EOA, EOAI and LVmass reduction were detected between the two groups. Conclusions (1)The EOA and in vivo hemodynamic effects of 19mm Regent valve are similar to 21mm other double leaflet mechanical valve. (2)It is safe to use 19mm Regent valve in those patients whose aortic annular diameter are small and need double valve replacement. Using 19mm Regent valve will not cause short time cardiac episodes and PPM. (3)More further works should be done to make sure what is the standard of PPM in Chinese people, such as enlarging the patients number and prolonging the followup time. (4) Further clinical and followup works should be done to make St.Jude Regent valve’s feature out.
Heart valve disease (HVD) is one of the common cardiovascular diseases. Heart sound is an important physiological signal for diagnosing HVDs. This paper proposed a model based on combination of basic component features and envelope autocorrelation features to detect early HVDs. Initially, heart sound signals lasting 5 minutes were denoised by empirical mode decomposition (EMD) algorithm and segmented. Then the basic component features and envelope autocorrelation features of heart sound segments were extracted to construct heart sound feature set. Then the max-relevance and min-redundancy (MRMR) algorithm was utilized to select the optimal mixed feature subset. Finally, decision tree, support vector machine (SVM) and k-nearest neighbor (KNN) classifiers were trained to detect the early HVDs from the normal heart sounds and obtained the best accuracy of 99.9% in clinical database. Normal valve, abnormal semilunar valve and abnormal atrioventricular valve heart sounds were classified and the best accuracy was 99.8%. Moreover, normal valve, single-valve abnormal and multi-valve abnormal heart sounds were classified and the best accuracy was 98.2%. In public database, this method also obtained the good overall accuracy. The result demonstrated this proposed method had important value for the clinical diagnosis of early HVDs.
Objective To summarize the experiences of surgical treatment for periprosthetic leakage(PPL). Methods A total of 63 patients with PPL (mitral PPL in 34, aortic PPL in 29), age 41±12 years, underwent reoperation with prosthetic valve replacement from Dec. 1980 to Dec. 2005 in this department. Patient characteristics, operative profiles and follow-up data were described and analyzed in detail. Results The perioperative complications occurred in 11 patients (17.5%), five of whom died (the overall hospital mortality: 7.9%). Fifty-five patients were in close follow-up and three of them lost in that period, five patients died in late. Fifty patients long-term survivals were in New York Heart Association class Ⅰ-Ⅱ and follow-up evaluation by echocardiography showed no evidence of recurrence or residual PPL and PPL-related complications. Conclusion More attention should be paid to the study on etiology, pathophysiology, diagnostic methods, and clinical classification of PPL. For patients with PPL, reoperation with prosthetic valve replacement is considerably effective and can obtain an acceptable longterm results.