Standardized Definition of Structural Valve Degeneration for Surgical and Transcatheter Bioprosthetic Aortic Valves.

Bioprostheses are prone to structural valve degeneration, resulting in limited long-term durability. A significant challenge when comparing the durability of different types of bioprostheses is the lack of a standardized terminology for the definition of a degenerated valve. This issue becomes especially important when we try to compare the degeneration rate of surgically inserted and transcatheter bioprosthetic valves. This document, by the VIVID (Valve-in-Valve International Data), proposes practical and standardized definitions of valve degeneration and provides recommendations for the timing of clinical and imaging follow-up assessments accordingly. Its goal is to improve the quality of research and clinical care for patients with deteriorated bioprostheses by providing objective and strict criteria that can be utilized in future clinical trials. We hope that the adoption of these criteria by both the cardiological and surgical communities will lead to improved comparability and interpretation of durability analyses.

How biophysical in vivo testing techniques can be used to characterize full thickness skin equivalents.

BACKGROUND: The reliability of the biophysical properties of skin equivalents (SEs) remains a challenge for medical applications and for product efficacy tests following the European Directive 2003/15/EC2 on the prohibition of animal experiments for cosmetic products. METHODS: We propose to adapt the biophysical in vivo testing techniques to compare full thickness model growth vs. time. The interest in using such techniques lies in possible comparisons between in vivo and in vitro skin as well as monitoring samples over the culture time. RESULTS: High frequency ultrasound technique, optical coherence tomography (OCT), and laser scanning microscopy were used to analyze SEs morphology at days D42 and D60 whereas their microstructure was assessed through transmission electron microscopy and classical histology. A correlation between these observations and mechanical measurements has been proposed so as to underline the consequence of both the development of the dermis elastic fibers and the epidermis differentiation. CONCLUSION: Ultrasounds measurements show a highly homogeneous dermis whereas the OCT technique clearly distinguishes the stratum corneum and the living epidermis. The increase in the thicknesses of these layers as well as the growth in elastin and collagen fibers results in strong modifications of the samples mechanical properties.

Valve-in-valve procedure: importance of the anatomy of surgical bioprostheses.

Transcatheter aortic valve implantation is an accepted and established alternative to surgical aortic valve replacement for patients with severe symptomatic aortic valve stenosis and multiple comorbidities that would make open surgery a high-risk option. It has also evolved as a suitable treatment option for degenerative surgical heart valve disease, with considerable experience in the aortic and mitral positions. To enable a successful procedure, avoiding malposition, valve embolization and coronary obstruction, clinicians should be familiar with the design, fluoroscopic appearances and implantation technique of the degenerated surgical bioprosthetic valve in situ, as well as its compatibility with currently available transcatheter valves.

The Bentall procedure with a biological valved conduit: substitute options and techniques.

As originally described by Bentall and De Bono, aortic root replacement with reimplantation of the coronary arteries using a composite valved conduit represents the gold standard intervention in patients with aneurysmal disease or dissection involving the aortic root. Over the last decade, the number of Bentall procedures performed using biological valved conduit has dramatically expanded mainly due to the increased incidence of aortic disease in the aging population. Here, we sought to describe the commercially available biological composite grafts and the techniques that, to the best of our knowledge, are most frequently used in this setting.

Concomitant transapical treatment of aortic stenosis and degenerated mitral bioprosthesis with two 29 mm Edwards Sapien XT prostheses.

An 85-year-old woman was admitted to our institution for effort dyspnea. She had a history of mitral valve replacement with a 29 mm Carpentier-Edwards bioprosthesis (Edwards Lifesciences). Transthoracic echocardiography (TTE) showed aortic stenosis and senescence of the mitral bioprosthesis. The heart team opted for a transapical transcatheter aortic valve implantation (TAVI) and mitral valve-in-valve implantation (m-ViV). Two Edwards Sapien XT (ESXT) 29 mm devices were selected. To our knowledge, this is the first description of the concomitant transapical implantation of two 29 mm ESXTs for a combination of failed mitral bioprosthesis and native aortic stenosis.

Durability of bioprosthetic valves in the pulmonary position: long-term follow-up of 181 implants in patients with congenital heart disease.

OBJECTIVES: Durability of bioprosthetic valves in the pulmonary position is not well defined. We examined the durability of bioprosthetic valves in the pulmonary position and risk factors associated with bioprosthetic pulmonary valve failure. METHODS: Between 1993 and 2004, 181 patients underwent pulmonary valve replacement using bioprostheses. Patients who underwent valved conduit or homograft implantation were excluded. Mean age was 14.2 ± 9.8 years and median valve size was 23 mm (range, 19-27 mm). Types of bioprosthesis used were Hancock II (n = 83), Perimount (n = 53), Freestyle (n = 23), Carpentier-Edwards porcine valve (n = 18), and others (n = 4). RESULTS: There were 3 early and 7 late deaths. Follow-up completeness was 88.6% and mean follow-up duration was 7.3 ± 2.9 years. Forty-three patients underwent redo pulmonary valve replacement. Overall freedom from redo pulmonary valve replacement at 5 and 10 years was 93.9% ± 1.9% and 51.7% ± 8.6%, respectively. Overall freedom from both valve failure and valve dysfunction at 5 and 10 years was 92.2% ± 2.1% and 20.2% ± 6.7%, respectively. In multivariable analysis, younger age at operation, diagnosis of pulmonary atresia with ventricular septal defect, and use of stentless valve were identified as risk factors for redo pulmonary valve replacement. CONCLUSIONS: Durability of bioprosthetic valves in the pulmonary position was suboptimal. Valve function was maintained stable until 5 years after operation. By 10 years, however, about 80% will require reoperation or manifest valve dysfunction. In our experience, the stentless valve was less durable than stented valves.

[Does the material of stapes prosthesis influence hearing improvement in stapes surgery--retrospective analysis of 350 cases]. / Wplyw rodzaju protezki strzemiqczka na stopien poprawy sluchu w chirurgii strzemiaczka--analiza retrospektywna 350 przypadków.

AIM: Retrospective analysis of the post-op hearing results in stapes surgery using different types of materials for stapes prosthesis after 12 months follow up. MATERIAL AND METHODS: The total number of 350 otosclerosis patients who underwent surgical treatment at the Otosurgery Department, Medical University of Lodz from 1980-2002. All patients included in the study were divided into 4 groups: group 1 (N=54)--Portmann's method interposition, group 2 (N=160)--stapes replaced with the Shea-type prosthesis, group 3 (N=60)--platinum wire prosthesis (Zini-type), group 4 (N=76)--teflon-piston operation (Fisch-type). RESULTS: The 12 months post-op mean value for air-bone gap (500, 1000, 2000 Hz) presented the following values: group 1-19 dB, group 2-15.9 dB, group 3-18.4 dB, group 4-13.5 dB. The percentage of patients with the mean air-bone gap value of 15 dB or less (500, 1000, 2000 Hz) has the following values in each group: group 1-75%, group 2-81.3%, group 3-83%, group 4-85%. CONCLUSIONS: 12 months post-op hearing results compared between the 4 studied groups showed statistically not significant differences. Our experience with teflon-piston prosthesis shows the lowest post-op mean value of the air-bone gap.

In vitro study of percutaneous aortic valve replacement: selection of a tissue valve.

BACKGROUND: Selection of the best tissue valve is an essential step before percutaneous aortic valve replacement (PAVR) becomes a clinical reality. The aim of this study was to evaluate in vitro three different tissue valves mounted within the same endovascular stent. METHODS: Thirty stented valves (10 aortic porcine, 10 pulmonary porcine, and 10 pericardial tubular) were sutured within a 32-mm long by 23-mm diameter cobalt-nickel stent. The porcine valves were trimmed down close to the cusps. All valves were delivered with a percutaneous valvuloplasty catheter and placed orthotopically in a latex root that was cast from a sheep's aorta. The roots were tested in a pulse duplicator at a rate of 60 beats per minute and 3.5 liters per minute. The transvalvular gradient, maximum valve orifice area, and presence of central and paravalvular leaks were recorded echocardiographically. RESULTS: Within the limitations of implantation in a synthetic, noncalcified annulus, the pericardial valve performed best in terms of orifice area, transvalvular gradients, and tissue bulk; but four of the ten valves showed a central leak due to the type of stent used. CONCLUSION: The ideal valve for PAVR should collapse with minimal bulk to avoid coronary obstruction and central and paravalvular leaks. The tubular pericardial valve showed the lowest pressure gradients and was the most compressible, but was more open to manufacturing errors.

Hemodynamic performance and clinical consequences of aortic valve replacement with 21-mm sized pericardial bioprostheses.

BACKGROUND: Aortic valve replacement (AVR) with a 21-mm sized bioprothesis is still discussed controversially. Since better results have been reported for pericardial valves, the aim of the current study was to analyze the hemodynamic performance as well as clinical parameters in our patients and to compare pericardial and standard porcine valves in particular. METHODS: 342 patients underwent AVR with a bioprosthesis between 1987 and 2000. A 21 mm prosthesis was used in 39 patients (group S), while 303 patients received at least a 23-mm sized valve (group L). Group S was further divided into 19 patients with a pericardial valve (group S1) and 20 patients with a standard porcine valve (group S2). The hemodynamic and clinical parameters were studied in all three groups. RESULTS: The peak and mean transprosthetic gradients were significantly lower in the pericardial group than in the porcine group, particularly between patients with 21 mm valves (peak/mean: S1: 24 +/- 9/20.8 +/- 6.5 mm Hg vs. S2: 38 +/- 15/33 +/- 9 mm Hg, p < 0.05) at discharge. We could also observe that the peak transprosthetic gradient 7 days postoperatively was not significantly higher in patients with a 21 mm pericardial valve compared to group L patients. Comparing clinical parameters, we found significantly more cerebral ischemic events, a prolonged mechanical ventilation, a higher mortality and a longer stay in hospital in the group S2 compared to the group S1. CONCLUSION: The current study shows that pericardial valves perform well, particularly in patients with small aortic roots. Postoperative hemodynamics and clinical results were better than for comparable standard porcine valves. As the outcome of patients with a 21 mm pericardial valve was no worse than that in patients with bigger valves, enlarging procedures for the aortic root are not necessary in the majority of these patients.

Biometrial-associated infections in surgery: part II: clinical perspective

O quadro clinico da infeccao associada a biomateriais e bastante variavel. Pode se apresentar de uma maneira aguda ou cronica, dependendo, na maioria dos casos, da etiologia bacteriana. Este tipo de infeccao deve ser vista como uma infeccao hospitalar e, como tal, medidas profilaticas como tecnica cirurgica apurada, competente cuidado pos-operatorio e um uso apropriado de antimicrobianos, sao capazes de diminuir o risco de infeccao destes pacientes. A infeccao em biomateriais associa-se frequentemente com um serio dilema clinico pois, na maioria dos casos, este tipo de infeccao e resistente ao uso de antimicrobianos e a remocao da protese e vista como a unica alternativa de tratamento para o paciente...

Valve prosthesis hemodynamics and the problem of high transprosthetic pressure gradients.

Recent studies suggest that all prosthetic valves are at least mildly stenotic and may cause relatively high pressure gradients despite normal prosthesis function; such gradients could be due to a mismatch between prosthesis effective orifice area and patient's body size. In order to address this problem more directly, we derived, using a physiologic pulse duplicator system, the theoretical relations between transprosthetic pressure gradients and prosthesis effective orifice areas indexed for body surface area, assuming a normal resting cardiac index of 3.0 l/min m-2 and 10-50% increases in stroke volume such as may occur during maximal upright exercise. These exponential relations show that a small decrease in indexed effective orifice area produces a large increase in pressure gradient, and that the indexed effective orifice area should ideally be not less than 0.9-1.0 cm2/m2 for aortic prostheses and 1.3-1.5 cm2/m2 for mitral prostheses in order to minimize postoperative gradients. Thus, high postoperative gradients do not necessarily indicate intrinsic prosthesis dysfunction but may also be due to patient prosthesis mismatch. Intrinsic prosthetic performance is best assessed by comparing in vivo calculated effective orifice areas to in vitro measurements for same type and size of prosthesis. Patient prosthesis mismatch can be avoided by calculating before operation the projected indexed effective orifice area of the prosthesis being implanted.

The stentless bioprosthesis: surgical challenges and implications for long-term durability.

An attempt is made to analyse the factors which are expected to influence clinical results following implantation of a stentless porcine bioprosthesis. Long experience with implantation of allograft aortic valves provides a meaningful basis for comparison with a glutaraldehyde-fixed device. Morphological differences between the two valves involve the aortic wall and muscle shelf, and differences in valve preparation include the strength and stiffness of the aorta and the extensibility of the valve leaflets. As a result of these differences, sizing of the porcine valve is expected to be more critical than the allograft valve and the porcine valve is also expected to be more obstructive. Methods for reducing the obstructive element include the use of a composite aortic valve, a porcine pulmonary valve, or a valve in which the aorta is glutaraldehyde-fixed under pressure while the leaflets are pressure-free. The techniques available for implantation, namely freehand insertion, total root replacement and mini-root replacement, are examined.

The first step to understanding valve failure: an overview of pathology.

The most frequent valve-related complications are thromboembolic problems (including anticoagulant-related hemorrhage), infective endocarditis, paravalvular leak, intrinsic degradative dysfunction, and extrinsic interference with function, including tissue overgrowth. Tissue overgrowth, endocarditis, and paravalvular leak are largely prosthesis-independent. Thrombosis, the major cause of mechanical valve dysfunction, is infrequent with bioprostheses; in contrast, the overwhelming cause of bioprosthetic valve failure is primary tissue degeneration.