Calcificación anillo mitral: reemplazo mitral con prótesis mecánica en posición supra anular / Mitral annular calcification: mitral valve replacement with mechanical prosthesis in supra annular position

Abstract: An 84 year old woman presented with recurrent severe heart failure. She had a heavily calcified mitral valve annulus. Radiological images before and after a mechanical valve was implanted in a supra annular position are shown.

Un caso clínico de implante valve in valve mitral: nuevo horizonte en el tratamiento de la disfunción valvular protésica / A clinical case of mitral valve in valve implant: new skyline in the treatment of prosthetic valve dysfunction / Presentação de um caso clínico do valve in valve mitral: um novo horizonte no tratamento da disfunção valvular protética

La disfunción valvular protésica es cada vez más frecuente debido al envejecimiento de la población portadora de bioprótesis y se presenta como un desafío en el momento de su diagnóstico, valoración y tratamiento. Aplicar un enfoque imagenológico multimodal es fundamental para su manejo. Respecto al tratamiento, surge como nueva alternativa un procedimiento mínimamente invasivo de sustitución valvular percutánea, denominado valve in valve, principalmente en pacientes con riesgo quirúrgico elevado. Presentamos uno de los primeros casos locales de implante percutáneo de prótesis mitral transeptal dentro de una bioprótesis mitral quirúrgica disfuncionante.

Prosthetic valve dysfunction is increasingly common due to the aging of the bioprosthesis-bearing population, and it presents a challenge at the time of diagnosis, evaluation, and treatment. A multimodal imaging approach is essential for its management. In relation to treatment, a minimally invasive percutaneous valve replacement procedure called valve in valve arises as a new alternative, mainly in patients with high surgical risk. We present one of first local cases of percutaneous implantation of a transseptal mitral prosthesis within a dysfunctional surgical mitral bioprosthesis.

A disfunção valvular protética é cada vez mais comum devido ao envelhecimento da população portadora de biopróteses e representa um desafio no momento do diagnóstico, avaliação e tratamento. A multimodalidade da imagem cardiovascular é essencial para sua avaliação. Em relação ao tratamento, um procedimento de troca valvular percutânea minimamente invasivo, denominado valve in valve, surge como uma nova alternativa, principalmente em pacientes com alto risco cirúrgico. Apresentamos um dos primeiros casos realizados no Uruguai de implantação percutânea de prótese mitral transeptal dentro de bioprótese mitral cirúrgica disfuncional.

Valvular surgery in donor hearts before orthotopic heart transplantation.

BACKGROUND: Donor heart shortage has extended the waiting time and increased the mortality of patients on the transplant waiting list. Widening old standard donor criteria has successfully increased the number of heart transplantations, but for many years, a valve disease in a donor heart has been considered a primary contraindication for organ donation. AIMS: To analyse the results of aortic and mitral valvular surgery in marginal donor hearts with valvulopathy before orthotopic heart transplantation. METHODS: Between January 2012 and November 2015, we performed 53 heart transplantations in our department. In four donors, echocardiography performed at the time of organ procurement showed a valvular disease: three had moderate-to-severe mitral regurgitation; and one had moderately severe aortic valve stenosis. RESULTS: The mean bench mitral repair and aortic replacement time, aortic cross-clamp time and total ischaemic time were: 18 (range 7-25) minutes, 78.7 (range 57-98) minutes and 184 (range 89-255) minutes, respectively. Intraoperative transoesophageal echocardiography showed good mitral repair or aortic prosthetic valve function, and good right and left ventricular function. One patient died of infectious pneumonia after 1 month. The mean duration of follow-up for the patients discharged home was 75±13 months, and all have returned to an active unrestricted lifestyle. CONCLUSIONS: Our limited series demonstrates that conventional valvular procedures performed on otherwise healthy donor hearts with mitral and aortic valve pathology can efficaciously expand the donor pool for orthotopic cardiac transplantation and decrease the mortality rate on the waiting list.

First Experience of Sutureless Redo on Mitral Valve Using Valve-in-Valve Technique: Two-Stage Implantation on a Large Animal.

Sutureless implantation of the mitral valve bioprosthesis using the valve-in-valve method was performed on a large animal (sheep). According to the results of a two-stage implantation (primary implantation of a xenopericardial 26-mm framed bioprosthesis and reimplantation of the developed 23-mm bioprosthesis), minor changes in quantitative indicators were revealed: an increase in the transprosthetic gradient by 1.3 mm Hg and a decrease in the area of the mitral orifice by 21.6%. Considerable reduction in the intervention time by 18 min was achieved (by 40% in comparison with the primary prosthesis). The absence of adverse events in the animal and complications in the post-operative period, as well as physiological hemodynamic indicators indicate the safety of the developed medical device.

Transplantation of a decellularized mitral valve complex in pigs.

PURPOSE: Conventional mitral valve replacement is associated with the loss of natural continuity of the mitral valve complex. This study evaluated the morphologic/histological characteristics and function of a decellularized mitral valve used as a transplantable graft. METHODS: Hearts excised from pigs were decellularized by perfusion using detergent. Grafts with the mitral annulus, valve, chordae, and papillary muscle isolated from the decellularized heart were then transplanted into recipient pigs. After transplantation, the function of the graft was analyzed through echocardiography. A histological analysis was performed to evaluate the postoperative features of the decellularized graft. RESULTS: The decellularized graft was successfully transplanted in all cases but one. The remaining grafts maintained their morphology and function. They did not exhibit mitral regurgitation or stenosis. Only one animal survived for 3 weeks, and a histological analysis was able to be performed in this case. The transplanted valve was re-covered with endothelial cells. The microvessels in the papillary muscle were recellularized with vascular endothelial cells, and the papillary muscle was completely attached to the papillary muscle of the recipient. CONCLUSION: The early outcome of decellularized mitral graft transplantation was acceptable. This native organ-derived acellular scaffold is a promising candidate for the replacement of the mitral valve complex.

A High Doppler Gradient: Obstruction or No Obstruction?: A Case Report.

The angle correction feature in ultrasound systems is used when there is difficulty accurately aligning the Doppler beam with the flow to be interrogated. The operator can manually "correct" the angle to the actual direction of flow. Subsequently, the machine corrects the peak velocity for the angle. We present a case of aortic valve replacement (AVR) in which falsely high transaortic gradients were obtained immediately after separation from cardiopulmonary bypass (CPB). We recommend that there be a more prominent notification when the angle correction feature is used with machine prompts confirming when a peak velocity is obtained using angle correction.

Atrial Fibrillation Predicts Long-Term Outcome after Transcatheter Edge-to-Edge Mitral Valve Repair by MitraClip Implantation.

Background: Atrial fibrillation is common in patients with mitral regurgitation (MR) and has a negative impact on the clinical outcome of patients with valvular heart disease. We aimed to evaluate the impact of pre-procedural atrial fibrillation on the long-term clinical outcomes of patients with MR undergoing transcatheter mitral valve repair by MitraClip implantation. Methods: We analysed 355 consecutive patients with and without atrial fibrillation with symptomatic, severe MR and inoperability or high surgical risk undergoing MitraClip implantation in a three-year follow-up. Results: In patients with pre-procedural atrial fibrillation undergoing MitraClip implantation, we found advanced age, higher baseline NT-pro-BNP levels, increased left atrial diameter, and higher rate of severe tricuspid regurgitation, compared to patients with sinus rhythm. In the three-year follow-up after MitraClip implantation, mortality and major adverse cardiovascular and cerebral events (MACCE) occur significantly more often in patients with atrial fibrillation, compared to patients without atrial fibrillation. Multivariate regression analysis confirmed atrial fibrillation (hazard ratio 2.39, 95%-confidence interval 1.06⁻5.41, p = 0.036) as an independent predictor for three-year-mortality after MitraClip implantation. Conclusions: Atrial fibrillation is an independent predictor for long-term mortality after MitraClip implantation. We demonstrate the association of atrial fibrillation with mortality and MACCE in the long-term follow-up of patients undergoing MitraClip implantation.

[Structural Deterioration of a Bovine Pericardial Valve in a Tricuspid Position 14 Years Postoperatively;Report of a Case].

Although nonstructural dysfunction of a bioprosthesis caused by pannus formation or native valve attachment has been well described, structural valve deterioration( SVD) caused by calcification or tear of a bioprosthesis, especially a bovine pericardial valve, is very rare in the tricuspid position. We report a case of redo tricuspid valve surgery for SVD 14 years after tricuspid valve replacement( TVR) using a Carpentier-Edwards Perimount (CEP) pericardial valve. A 71-year-old woman was referred to our hospital because of exertional dyspnea and pre-syncope. She had undergone mitral valve replacement with a St. Jude Medical mechanical valve and TVR with a CEP pericardial valve 14 years previously. Transthoracic echocardiography revealed tricuspid valve stenosis with a mean trans-tricuspid valve pressure gradient (TVPG) of 7.3 mmHg. Redo TVR using a CEP Magna Mitral Ease valve was performed under cardiac arrest. Severe calcification was observed on the ventricular side of the leaflets of the explanted valve. The mean TVPG decreased to 3.2 mmHg after surgery, and the patient's postoperative course was uneventful.

Automated quantification of mitral valve geometry on multi-slice computed tomography in patients with dilated cardiomyopathy - Implications for transcatheter mitral valve replacement.

OBJECTIVES: The primary aim of this study was to quantify the dimensions and geometry of the mitral valve complex in patients with dilated cardiomyopathy and significant mitral regurgitation. The secondary aim was to evaluate the validity of an automated segmentation algorithm for assessment of the mitral valve compared to manual assessment on computed tomography. BACKGROUND: Transcatheter mitral valve replacement (TMVR) is an evolving technique which relies heavily on the lengthy evaluation of cardiac computed tomography (CT) datasets. Limited data is available on the dimensions and geometry of the mitral valve in pathological states throughout the cardiac cycle, which may have implications for TMVR device design, screening of suitable candidates and annular sizing prior to TMVR. METHODS: A retrospective study of 15 of patients with dilated cardiomyopathy who had undergone full multiphase ECG gated cardiac CT. A comprehensive evaluation of mitral valve geometry was performed at 10 phases of the cardiac cycle using the recommended D-shaped mitral valve annulus (MA) segmentation model using manual and automated CT interpretation platforms. Mitral annular dimensions and geometries were compared between manual and automated methods. RESULTS: Mitral valve dimensions in patients with dilated cardiomyopathy were similar to previously reported values (MAarea Diastole: 12.22 ±â€¯1.90 cm2), with dynamic changes in size and geometry between systole and diastole of up to 5%. The distance from the centre of the MA to the left ventricular apex demonstrated moderate agreement between automated and manual methods (ρc = 0.90) with other measurements demonstrating poor agreement between the two methods (ρc = 0.75-0.86). CONCLUSIONS: Variability of mitral valve annulus measurements are small during the cardiac cycle. Novel automated algorithms to determine cardiac cycle variations in mitral valve geometry may offer improved segmentation accuracy as well as improved CT interpretation times.

Tiara Valve Implantation in a Patient With Previously Implanted Mono-disk Mechanical Aortic Prosthesis.

Transcatheter mitral valve replacement with the Tiara valve can be performed in inoperable patients with severe functional regurgitation. Risk of left ventricular outflow tract obstruction can be prevented using preoperative 3D imaging and 3D-printed models. However, in the case of mono-disk mechanical prostheses previously implanted in aortic position (Bjork-Shiley), there is an additional risk of mechanical interference leading to reduced leaflet motion and aortic valve dysfunction. Hereafter, we describe the case of a patient with a 27-mm mono-disk mechanical aortic valve implanted in 1978, a EuroSCORE II of 18%, and a Society of Thoracic Surgeon score (mortality) of 16% who successfully underwent a transapical Tiara valve implantation.

Decellularized mitral valve in a long-term sheep model.

OBJECTIVES: The objective of this study was to evaluate surgical handling, in vivo hemodynamic performance and morphological characteristics of decellularized mitral valves (DMVs) in a long-term sheep model. METHODS: Ovine mitral valves were decellularized using detergents and ß-mercaptoethanol. Orthotopic implantations were performed in 6-month-old sheep (41.3 ± 1.2 kg, n = 11) without annulus reinforcement. Commercially available stented porcine aortic valves [biological mitral valve (BMV), n = 3] were implanted conventionally and used as controls. Valve function was evaluated by transoesophageal echocardiography and explants were investigated by a routine bright field microscopy and immunofluorescent histology. RESULTS: During implantation, 2 DMVs required cleft closure of the anterior leaflet. All valves were competent on water test and early postoperative transoesophageal echocardiography. Six animals (DMV, n = 4; BMV, n = 2) survived 12 months. Six animals died within the first 4 months due to valve-related complications. At 12 months, transoesophageal echocardiography revealed severe degeneration in all BMVs. Macroscopically, BMV revealed calcification at the commissures and leaflet insertion area. Histological examination showed sporadic cells negative for endothelial nitric oxide synthase, von Willebrand factor and CD45 on their surface. In contrast, DMV showed no calcification or stenosis, and the regurgitation was trivial to moderate in all animals. Fibrotic hardening occurred only along the suture line of the valve annulus, immunostaining revealed collagen IV covering the entire leaflet surface and a repopulation with endothelial cells. CONCLUSIONS: Surgical implantation of DMV is feasible and results in good early graft function. Additional in vivo investigations are required to minimize the procedure-related complications and to increase the reproducibility of surgical implantation. Degenerative profile of allogeneic DMV is superior to commercially available porcine aortic prosthesis.

Vegetation with a lizard-tail appearance in the left atrium / Vegetación en forma de cola de lagarto en aurícula izquierda

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Development and Characterization of a Porcine Mitral Valve Scaffold for Tissue Engineering.

Decellularized scaffolds represent a promising alternative for mitral valve (MV) replacement. This work developed and characterized a protocol for the decellularization of whole MVs. Porcine MVs were decellularized with 0.5% (w/v) SDS and 0.5% (w/v) SD and sterilized with 0.1% (v/v) PAA. Decellularized samples were seeded with human foreskin fibroblasts and human adipose-derived stem cells to investigate cellular repopulation and infiltration, and with human colony-forming endothelial cells to investigate collagen IV formation. Histology revealed an acellular scaffold with a generally conserved histoarchitecture, but collagen IV loss. Following decellularization, no significant changes were observed in the hydroxyproline content, but there was a significant reduction in the glycosaminoglycan content. SEM/TEM analysis confirmed cellular removal and loss of some extracellular matrix components. Collagen and elastin were generally preserved. The endothelial cells produced newly formed collagen IV on the non-cytotoxic scaffold. The protocol produced acellular scaffolds with generally preserved histoarchitecture, biochemistry, and biomechanics.

A systematic review and meta-analysis of chordal replacement versus leaflet resection for isolated posterior mitral valve prolapse.

INTRODUCTION: Chordal replacement (Chord MVr) for isolated posterior mitral valve prolapse allows for preservation of the native mitral valve apparatus. The potential benefits of this approach, as compared with leaflet resection (Resection), are not clearly defined. EVIDENCE ACQUISITION: A systematic review and meta-analysis was conducted on operative, clinical, and echocardiographic outcomes. Risk ratios (RR) were calculated by the Mantel-Haenszel method under a fixed or random effects model, as appropriate. EVIDENCE SYNTHESIS: Eight studies were included, with a total of 1922 patients (Chord MVr, N.=835; Resection, N.=1087). Baseline characteristics were similar, except for a higher incidence of atrial fibrillation in the Chord MVr group (15.5% versus 9.9%, P=0.03), and a slightly greater mitral regurgitation grade in the Resection group (3.5 versus 3.4, P=0.008). P2 segment prolapse was the most common pathology, however, patients undergoing Chord MVr had a higher incidence of multi-segment prolapse (32.1% versus 13.9%, P=0.0006). There was no difference in operative mortality (1.1% for both) or perioperative complications. At a mean follow-up of 2.9±2.8 years (median=2.8 years, IQR 1.6-4.4), Chord MVr was associated with a lower risk of reoperation (1.1% versus 4.3%; RR 0.26, 95% CI 0.12-0.56, P=0.0007), and similar survival and recurrence of moderate mitral regurgitation, when compared with Resection. Finally, a lower transmitral gradient (2.5 versus 2.8 mmHg, P=0.0004) and larger orifice area (3.2 versus 3.0 cm2, P=0.002) were observed with Chord MVr. CONCLUSIONS: At 2.9-year follow-up, Chord MVr for isolated posterior mitral valve prolapse was associated with a lower reoperation rate and favorable valve hemodynamics, when compared with leaflet resection.

Biomechanical drawbacks of different techniques of mitral neochordal implantation: When an apparently optimal repair can fail.

OBJECTIVES: Intraoperative assessment of the proper neochordal length during mitral plasty may be complex sometimes. Patient-specific finite element models were used to elucidate the biomechanical drawbacks underlying an apparently correct mitral repair for isolated posterior prolapse. METHODS: Preoperative patient-specific models were derived from cardiac magnetic resonance images; integrated with intraoperative surgical details to assess the location and extent of the prolapsing region, including the number and type of diseased chordae; and complemented by the biomechanical properties of mitral leaflets, chordae tendineae, and artificial neochordae. We investigated postoperative mitral valve biomechanics in a wide spectrum of different techniques (single neochorda, double neochordae, and preconfigured neochordal loop), all reestablishing adequate valvular competence, but differing in suboptimal millimetric expanded polytetrafluoroethylene suture lengths in a range of ±2 mm, compared with the corresponding "ideal repair." RESULTS: Despite the absence of residual regurgitation, alterations in chordal forces and leaflet stresses arose simulating suboptimal repairs; alterations were increasingly relevant as more complex prolapse anatomies were considered and were worst when simulating single neochorda implantation. Multiple chordae implantations were less sensitive to errors in neochordal length tuning, but associated postoperative biomechanics were hampered when asymmetric configurations were reproduced. Computational outcomes were consistent with the presence and entity of recurrent mitral regurgitation at midterm follow-up of simulated patients. CONCLUSIONS: Suboptimal suture length tuning significantly alters chordal forces and leaflet stresses, which may be key parameters in determining the long-term outcome of the repair. The comparison of the different simulated techniques suggests possible criteria for the selection and implementation of neochordae implantation techniques.

One-year results from cryopreserved mitral allograft transplantation into the tricuspid position in a sheep experimental model.

Mitral allografts are still used only exceptionally in the mitral or tricuspid position. The main indication remains infectious endocarditis of atrioventricular valves for its flexibility and low risk of infection. The aim of our study was to evaluate 1-year results of mitral allografts transplantation into the tricuspid position in a sheep model. Mitral allografts were processed, cryopreserved, and transplanted into the tricuspid position anatomically (Group I - 11 animals) or antianatomically (Group II - 8 animals). All survivors (4 from Group I, and 3 from Group II) were checked at 3, 6, and 12 months by echocardiography with the exception of one survivor from Group II (which was examinated only visually). Examination throughout follow-up included for mitral allograft regurgitation and annuli dilatation. At postmortem, the papillary muscles were healed and firmly anchored to the right ventricular wall in all subjects. Transventricular fixation of the papillary muscles with buttressed sutures was proven to be a stable, reproducible, and safe method for anchoring mitral allograft leaflets. There were no significant differences between the two implantation methods. Annulus support of mitral allografts might be very useful in this type of operation and could prevent annular dilatation.

Warfarin Metabolites in Patients Following Cardiac Valve Implantation: A Contribution of Clinical and Genetic Factors.

INTRODUCTION: Warfarin, a racemic mixture of S- and R-enantiomers, is the cornerstone of therapy in patients following cardiac valve replacement. S-warfarin is metabolized to 7-S-hydroxywarfarin by the cytochrome P450 isoform 2C9 encoded by CYP2C9 gene. R-warfarin is metabolized by multiple cytochromes P450. We sought to assess the impact of clinical and genetic factors on circulating warfarin metabolites following valve implantation. MATERIAL AND METHODS: Venous blood was collected from 120 patients after 3 months since elective mitral and/or aortic valve replacement. Plasma S-warfarin, R-warfarin, S-7-hydroxywarfarin, and R-7-hydroxywarfarin were determined using high-performance liquid chromatography. The S-7-hydroxywarfarin/S-warfarin and S-warfarin/R-warfarin (S/R) ratios, along with warfarin sensitivity index (WSI), defined as INR/S-warfarin ratio, were calculated. Vitamin K epoxide reductase complex subunit 1 (VKORC1) c.-1639A, CYP2C9*3 and CYP2C9*2 alleles were determined using real-time polymerase chain reaction. RESULTS: The S-warfarin was higher in former smokers (p = 0.047) and the VKORC1 c.-1639A allele carriers (p < 0.0001). The S-7-hydroxywarfarin was lower in carriers of the VKORC1 c.-1639A allele (p = 0.0005) and CYP2C9*3 (p = 0.047). The S-7-hydroxywarfarin/S-warfarin ratio was lower in the carriers of CYP2C9*3 (p = 0.008), but not in those with VKORC1 -c.1639A allele. The S/R ratio was higher in patients with hypertension (p = 0.01). The independent predictors of elevated S/R ratio defined as the upper quartile were diabetes (p = 0.045), CYP2C9*3 (p < 0.0001) and CYP2C9*2 (p = 0.0002). The independent predictors of elevated WSI were current smoking (p = 0.049), implantation of mechanical valve (p = 0.006) and VKORC1c.-1639A allele (p = 0.007). CONCLUSION: We conclude that not only genetic, but also several clinical factors affect warfarin metabolites in patients following cardiac valve implantation.