Use Of Prosthetic Valves Research Articles

Aortic valve neocuspidization using autologous versus bovine pericardium: Ozaki versus Batista.

The average living age of the population is constantly increasing and so is the incidence and prevalence of aortic valve disease. Surgical aortic valve replacement (SAVR) is the current gold standard treatment. Nevertheless, the use of prosthetic valves in SAVR is associated with issues that impact patients' quality of life. Aortic valve neocuspidization (AV Neo) offers a means to solve this dilemma by minimizing foreign valve tissue. AV Neo can either be performed using glutaraldehyde-treated autologous pericardium (Ozaki procedure) or bovine pericardium (Batista procedure). This commentary aims to discuss the recent study by Chan and colleagues which highlighted the surgical approach, clinical outcomes, and limitations of the Ozaki procedure, and compare this to the Batista procedure. A comprehensive literature search was performed using multiple electronic databases including PubMed, Ovid, Embase, and Scopus to collate the relevant research evidence. Although the Ozaki procedure can achieve favorable results whilst mainly avoiding the need for life-long oral anticoagulation with mechanical valves, it still has several limitations that may hinder results. AV Neo using glutaraldehyde-treated bovine pericardium, developed by pioneer cardiac surgeon Dr. Randas J. Vilela Batista, yields superior clinical outcomes to Ozaki's, including excellent survival, lower complications, and minimal need for reoperation as well as shorter operative times. AV Neo offers a means to perform SAVR whilst escaping the prosthetic valve issues. However, the Batista procedure has shown beyond doubt that it can be considered the superior approach for AV Neo over the Ozaki procedure.

Feasibility and Outcome of Cardiovascular Surgeries Combined with Ozaki Procedure; Single Center Single Surgeon Experience

Objective: Considering aortic valve surgeries, use of prosthetic valves is associated with issues of quality, technology, availability and affordability in developing countries like Sri Lanka. In such setting, Ozaki procedure can be used to treat spectrum of aortic valve diseases, and can be combined with other cardiac surgeries. This study focused on recapitulating the current practice of Ozaki procedure combined with other cardiac surgeries. Methods: This retrospective cross sectional study was carried out from October 2019 to October 2020 at National Hospital Kandy. All patients were operated by a single surgeon. Total number of patients were 10 (6 males, 4 females) with mean age 52 years. Severe aortic stenosis 6, severe aortic regurgitation 3, combination of both 1, were assigned for Ozaki procedure and combined as follows. One patient had undergone isolated Ozaki procedure following aortic valve vegetectomy. Results: All patients were successfully weaned from CPB. Intra-operative echocardiogram showed no significant aortic or mitral regurgitation. Ejection fraction was preserved at 50 ±10%. Mean cross-clamp time for AV reconstruction only was 92 ± 18 minutes and mean length of stay on the intensive care unit was 70 ± 18 hours and hospital stay was 6 ± 1.5 days after combined procedures. No pacemaker implanted after all procedure. No reoperation done. Conclusions: In our experience, this technique can be mastered after a relatively short training period, can be used for variety of aortic valvular pathology, can combined successfully with other surgeries and even with aortic conduits. Ozaki procedure remains a very attractive strategy with excellent haemodynamics and may have the potential to overcome the structural disadvantages of prosthetic valves including use of warfarin. Combined procedure No of cases Coronary artery bypass grafting 5 Mitral valve ring annuloplasty 1 Coronary artery bypass grafting/ Mitral valve ring annuloplasty 1 Ascending aortic replacement 2

Design, Modeling, and Experimental Characterization of A Valveless Pulsatile Flow Mechanical Circulatory Support Device

Abstract Mechanical circulatory support (MCS) devices, i.e., ventricular assist devices (VADs) and total artificial hearts (TAHs), while effective and vital in restoring hemodynamics in patients with circulatory compromise in advanced heart failure, remain limited by significant adverse thrombotic, embolic and bleeding events. Many of these complications relate to chronic exposure, via these devices, to nonpulsatile flow and the high shear stress created by current methods of blood propulsion or use of prosthetic valves. Here we propose a novel noncompressing single sliding vane MCS device to: 1) dramatically reduce pump operating speed thus potentially lowering the shear stress imparted to blood; 2) eliminate utilization of prosthetic valves thus diminishing potential shear stress generations; 3) allow direct flow rate control to generate physically desired blood flow rate include pulsatile flow; and 4) achieve compactness to fit into the majority of patients. The fundamental working principle and governing design equations are introduced first with multiple design and performance objectives presented. A first prototype was fabricated and experimental tests were conducted to validate the model with a 93.10% match between theoretical and experimental flow rate results. After model validation, the proposed MCS was tested to illustrate the ability of pulsatile flow generation. Finally, it was compared with some representative MCS pumps to discuss its potential of improving current MCS design. The presented work offers a novel MCS design and paves the way for next steps in device hemocompatibility testing.

Paravalvular Leak Assessment: Challenges in Assessing Severity and Interventional Approaches.

With increasing use of prosthetic valves to treat degenerative valvular heart disease (VHD) in an aging population, the incidence and adverse consequences of paravalvular leaks (PVL) are better recognized. The present work aims to provide a cohesive review of the available literature in order to better guide the evaluation and management of PVL. Despite gains in operator experience and design innovation, significant PVL remains a significant complication that may present with congestive heart failure and/or hemolytic anemia. To date, clear consensus or guidelines on the evaluation and management of PVL remain lacking. Although the evolution of transcatheter valve therapies has had a tremendous impact on the management of patients with VHD, the limitations and complications of such techniques, including PVL, present further challenges. Incidence of PVL, graded as moderate or greater, ranges from 4 to 7.4% in surgical and transcatheter valve replacements, respectively. Improved imaging modalities and the advent of novel surgical and percutaneous therapies have undoubtedly yielded a better understanding of PVL including its anatomical location, mechanism, severity, and treatment options. Echocardiography, used in conjunction with cardiac computed tomography and cardiac magnetic resonance, provides essential details for diagnosis and management of PVL. Transcatheter intervention has become a favored approach in lieu of surgical intervention in select patients after previous surgical or percutaneous valve replacement. PVL treatment with vascular plugs, balloon post-dilation, and the valve-in-valve methods have shown technical success with promising clinical outcomes in appropriately selected patients.

Surgery for rheumatic mitral valve disease in sub-saharan African countries: why valve repair is still the best surgical option

Rheumatic valve disease, a consequence of acute rheumatic fever, remains endemic in developing countries in the sub-Saharan region where it is the leading cause of heart failure and cardiovascular death, involving predominantly a young population. The involvement of the mitral valve is pathognomonic and mitral surgery has become the lone therapeutic option for the majority of these patients. However, controversies exist on the choice between valve repair or prosthetic valve replacement. Although the advantages of mitral valve repair over prosthetic valve replacement in degenerative mitral disease are well established, this has not been the case for rheumatic lesions, where the use of prosthetic valves, specifically mechanical devices, even in poorly compliant populations remains very common. These patients deserve more accurate evaluation in the choice of the surgical strategy which strongly impacts the post-operative outcomes. This report discusses the factors supporting mitral repair surgery in rheumatic disease, according to the patients' characteristics and the effectiveness of the current repair techniques compared to prosthetic valve replacement in developing countries.

Mid-term outcome of mechanical pulmonary valve prostheses: the importance of anticoagulation.

Introduction: Pulmonary valve replacement (PVR) is being performed more commonly late after the correction of tetralogy of Fallot. Most valves are replaced with an allograft or xenograft, although reoperations are a common theme. Mechanical prostheses have a less favorable reputation due to the necessity of lifelong anticoagulation therapy and higher risk of thrombosis, but they are also less likely to require reoperation. There is a paucity of data on the use of prosthetic valves in the pulmonary position. We report the midterm outcomes of 38 cases of PVR with mechanical prostheses. Methods: One hundred twenty two patients who underwent PVR were studied. Thirty-eight patients, mean age 25 ± 8.4 years underwent PVR with mechanical prostheses based on the right ventricular function and the preferences of the patients and physicians. Median age of prosthesis was 1 year (range 3 months to 5 years). Results: Seven (18%) patients had malfunctioning pulmonary prostheses and two patients underwent redo PVR. Mean International Normalized Ratio (INR) in these seven patients was 2.1±0.8. Fibrinolytic therapy was tried and five of them responded to it well. There was no significant association between the severity of right ventricular dysfunction, patient’s age, prostheses valve size and age of the prosthesis in the patients with prosthesis malfunction. Conclusion: PVR with mechanical prostheses can be performed with promising midterm outcomes. Thrombosis on mechanical pulmonary valve prostheses remains a serious complication, but most prosthesis malfunction respond to fibrinolytic therapy, underscoring the need for adequate anticoagulation therapy.

The Ross Procedure: Clinical and Echocardiographic Follow-Up in 219 Consecutive Patients

The replacement of the diseased aortic valve with a pulmonary autograft has been shown to provide excellent hemodynamic results and to be associated with low morbidity and mortality rates. From 1991 to 2005, 219 patients undergoing the Ross operation were identified. All patients underwent transthoracic echocardiography at discharge and were scheduled for a yearly study thereafter. The echocardiographic study consisted of a morphologic analysis of the pulmonary autograft with measurement of end-systolic diameters at three levels: annulus, sinuses of Valsalva, and origin of the ascending aorta 2 cm above the sinotubular junction. The dynamic analysis evaluated the function of the aortic autograft and the pulmonary homograft. Maximal and mean aortic and pulmonary transvalvular pressure gradients were investigated. The 30-day mortality was 1.8% (n = 4). Cardiac deaths were not related to the autograft. The 10-year actuarial survival was 95.7% +/- 2.1%. Six patients (2.8%) had grade 2 autograft valve regurgitation. No grade 3 or 4 pulmonary regurgitation was identified. At their most recent follow-up, 28 patients (13.1%) had grade 1 insufficiency of the pulmonary homograft, and 10 patients (4.6%) had a peak transvalvular gradient of 17.9 +/- 10.2 mm Hg. Our current experience suggests that replacement of the aortic root with a pulmonary autograft can be safely performed in infants, children, and adults and is associated with low mortality and morbidity rates. It constitutes an elegant alternative to the use of prosthetic valves in the treatment of aortic valve diseases.

Invited commentary

Invited commentary

Surgical management of isolated congenital tricuspid regurgitation

Background. Isolated congenital tricuspid regurgitation without downward displacement of the leaflet is a rare clinical entity. Degenerative cusps and lack of chordae may preclude valvuloplasty and require valve replacement. Methods. Three consecutive patients with isolated congenital tricuspid regurgitation underwent surgical repair between May 1995 and April 1997. Their ages were 23, 15, and 8 years old. Tricuspid valvuloplasty was feasible in all of them, with use of a gathering suture of the anterior leaflet, artificial chordae implantation, and ring annuloplasty. Results. All 3 patients survived and recovered well after the operation. The cardiothoracic ratios on their chest roentgenograms decreased from 0.64 to 0.52 in patient 1, from 0.58 to 0.48 in patient 2, and from 0.60 to 0.44 in patient 3. Postoperative echocardiograms showed competent tricuspid valves and the disappearance of regurgitation in all cases. Conclusions. Although malformation of the valve is extensive in isolated congenital tricuspid regurgitation, application of artificial chordae with conventional valvuloplasty technique can avoid the use of prosthetic valves by establishing the competence of the tricuspid valve.

Valve Replacement in Children

With increasing experience in the surgical management of children with congenital heart disease has come an increasing use of prosthetic valves. They have been employed in a wide variety of conditions ranging from simple congenital stenosis or incompetence to an essential part of repair of more complex disorders. As in adult cardiac surgery, there has been considerable debate over the exact prostheses that should be used in individual circumstances. As we point out in this article, experience has varied both geographically and with time. Our own experience at Great Ormond Street, for example, has been of initial satisfaction with results of mechanical valves followed by enthusiasm for, sequentially, the Hancock and the Ionescu prostheses. Now we have turned full circle and predominantly use mechanical valves, primarily owing to the extraordinary incidence of premature, degenerative calcification of bioprosthetic valves in children. The exact rates of degeneration of these valves are variable; thus it is difficult to relate prosthesis survival to the growth rate of the child. The experience with homograft valve replacements is encouraging, since they do not seem to degenerate so rapidly. Valve replacement in children carries a high risk. The younger the child, the higher the risk, with mitral valve replacement being the most dangerous procedure of all. We conclude that valve replacement in children is a procedure that should not be taken lightly and for which, at present, mechanical valves offer the best prognosis, despite the small risk of anticoagulation.

Valve replacement in children.

AbstractWith increasing experience in the surgical management of children with congenital heart disease has come an increasing use of prosthetic valves. They have been employed in a wide variety of conditions ranging from simple congenital stenosis or incompetence to an essential part of repair of more complex disorders. As in adult cardiac surgery, there has been considerable debate over the exact prostheses that should be used in individual circumstances. As we point out in this article, experience has varied both geographically and with time. Our own experience at Great Ormond Street, for example, has been of initial satisfaction with results of mechanical valves followed by enthusiasm for, sequentially, the Hancock and the Ionescu prostheses. Now we have turned full circle and predominantly use mechanical valves, primarily owing to the extraordinary incidence of premature, degenerative calcification of bioprosthetic valves in children. The exact rates of degeneration of these valves are variable; thus it is difficult to relate prosthesis survival to the growth rate of the child. The experience with homograft valve replacements is encouraging, since they do not seem to degenerate so rapidly. Valve replacement in children carries a high risk. The younger the child, the higher the risk, with mitral valve replacement being the most dangerous procedure of all. We conclude that valve replacement in children is a procedure that should not be taken lightly and for which, at present, mechanical valves offer the best prognosis, despite the small risk of anticoagulation.

Mitral valve replacement in the baboon (Papio ursinus) and the human with the University of Stellenbosch mitral valve prosthesis

To study the problem of thromboembolism that occurs following the use of prosthetic valves, the mitral valve was replaced in 20 Cape Chagma baboons with the University of Stellenbosch (U.S.B.) mitral valve prosthesis. In the absence of anticoagulants massive thrombus invariably formed on the metal portion of the prosthesis when the latter was left uncovered by material that allows for tissue ingrowth. Smooth, fairly well controlled tissue ingrowth occurred when the prosthetic ring was covered by Dacron velour material. Massive thrombus formation was never encountered although small fibrin thrombi, a potential source of emboli, became loosely attached to the Dacron velour covered prosthetic ring during the first eight post-operative weeks. Thereafter the smooth ingrowth of living tissue into the prosthesis appears capable of preventing thromboembolism. The clinical use of anticoagulants during the initial 3-4 post-operative months is recommended in view of our experimental findings and clinical experience of early embolism that occurred in 3 of 10 patients in whom the U.S.B. Dacron velour covered prosthesis was used in the absence of anticoagulants. This is the first reported study in which a sub-human primate was used to study the problem of thromboembolism associated with prosthetic valve replacement. The baboon can be highly recommended for this purpose.

Heart valve replacement with reinforced aortic heterografts: Technique and results

Summary Because of the disadvantages connected with the use of prosthetic valves, a technique for heart valve replacement was developed using reinforced heterologous aortic valves. Two types of graft were used clinically. One of them, a reconstructed aortic valve reinforced with a semirigid Teflon ring, was used for mitral valve replacement only. The second one, an aortic valve attached to a Dacron-covered titanium frame, was used for replacing the mitral, aortic, and tricuspid valves. The technique for preparing and inserting these grafts is briefly described. Since February, 1967, 63 patients were operated upon by means of this technique. In 48 patients the mitral valve was replaced, in 9 the aortic, in 3 the mitral and tricuspid valves, in 2 the mitral, aortic and tricuspid valves, and in 1 patient the tricuspid valve only. There have been thirteen deaths. Ten patients died within the first 6 weeks postoperatively from causes not related to the graft, and 3 died 7, 8, and 16 weeks, respectively, after the operation because of graft failure. These 3 patients were operated upon early in this series and had the grafts reinforced with a Teflon ring. Fifty patients were greatly benefited by surgery. No systemic embolization occurred, although anticoagulants were not used for more than 4 to 6 weeks postoperatively. Data concerning follow-up studies up to 14 months since the operation are presented to evaluate the results obtained (clinical condition, mechanograms, catheter findings, angiography). Technical and biologic reasons for using this method are given and the long-term fate of devitalized aortic heterografts as heart valve replacement, with clinical and experimental data, is discussed. The authors are grateful to Miss M. Gallagher, Miss E. Loach, and Miss P. Massey, Dr. Y. A. S. Mashhour, Dr. B. J. Garcia, and Dr. A. Barankay for their help in the operating theatre and in the postoperative management of these patients.

MITRAL VALVE REPLACEMENT IN CHILDREN

SUMMARY The cases of 2 children with severe mitral insufficiency have been presented with emphasis on the pathologic physiology and surgical treatment. The Starr-Edwards prosthesis was used to totally replace the diseased mitral valve in each instance. In selected cases, the use of prosthetic valves is indicated for the treatment of severe mitral valvular disease in children.

Criteria for surgery in aortic valvular disease

Aortic valvular disease in many patients causes progressive myocardial impairment leading to premature death. The present state of progress in surgical correction would indicate operative therapy at the onset of symptoms. The results so far in the use of prosthetic valves demonstrated that this is an effective method of treatment in the surgical correction of these valvular deformities.