A comparison of outcomes in men 11 years after heart-valve replacement with a mechanical valve or bioprosthesis. Veterans Affairs Cooperative Study on Valvular Heart Disease

Myocardial infarction due to coronary embolism after mechanical aortic valve replacement: a case report

Prosthetic valve thrombosis (PVT) in aortic valve and its complication coronary embolism is a very rare condition. Diagnosis and treatment process is challenging. We present a young patient with acute myocardial infarction who underwent mechanical aortic valve replacement (AVR) operation one month earlier. Percutaneous coronary intervention was performed and it was succesful. Transeasophageal ecocardiography (TEE) was performed. Thrombus was seen on the mechanical aortic valve and thrombolytic therapy was initiated. Control TEE was performed and there was no signs of thrombi. The patient was discharged healthfully with anticoagulant and antiaggregan.

Healthcare exposures and associated risk of endocarditis after open-heart cardiac valve surgery

BACKGROUND

Infective endocarditis (IE) following cardiac valve surgery is associated with high morbidity and mortality. Data on the impact of iatrogenic healthcare exposures on this risk are sparse. This study aimed to investigate risk factors including healthcare exposures for post open-heart cardiac valve surgery endocarditis (PVE).

METHODS

In this population-linkage cohort study, 23,720 patients who had their first cardiac valve surgery between 2001 and 2017 were identified from an Australian state-wide hospital-admission database and followed-up to 31 December 2018. Risk factors for PVE were identified from multivariable Cox regression analysis and verified using a case-crossover design sensitivity analysis.

RESULTS

In 23,720 study participants (median age 73, 63% male), the cumulative incidence of PVE 15 years after cardiac valve surgery was 7.8% (95% CI 7.3-8.3%). Thirty-seven percent of PVE was healthcare-associated, which included red cell transfusions (16% of healthcare exposures) and coronary angiograms (7%). The risk of PVE was elevated for 90 days after red cell transfusion (HR = 3.4, 95% CI 2.1-5.4), coronary angiogram (HR = 4.0, 95% CI 2.3-7.0), and healthcare exposures in general (HR = 4.0, 95% CI 3.3-4.8) (all p < 0.001). Sensitivity analysis confirmed red cell transfusion (odds ratio [OR] = 3.9, 95% CI 1.8-8.1) and coronary angiogram (OR = 2.6, 95% CI 1.5-4.6) (both p < 0.001) were associated with PVE. Six-month mortality after PVE was 24% and was higher for healthcare-associated PVE than for non-healthcare-associated PVE (HR = 1.3, 95% CI 1.1-1.5, p = 0.002).

CONCLUSIONS

The risk of PVE is significantly higher for 90 days after healthcare exposures and associated with high mortality.

Rates and Predictors of Structural Valve Degeneration and Failure of Trifecta Bioprosthetic Valve Over a 5-year Follow-up Period: A Single-center Experience

Introduction

The Trifecta bioprosthetic valve has been commonly used for surgical aortic valve replacement (SAVR). Multiple studies have been done to define the rate of structural valve degeneration (SVD) and failure (SVF), but the outcomes are still debatable. Therefore, we aim to conduct this single-center study to estimate the rate and predictors of SVD/SVF.

Methodology

This retrospective observational cohort single-center study was conducted between 2014 and 2019 among Trifecta SAVR patients. Data were patient's characteristics collected from electronic medical records at baseline and follow-up (3-5 years). Statistical analysis was performed with a significance level of P ≤ 0.05.

Results

A total of 271 eligible patients were identified. Most of our sample were males (57.9%), with a mean age of 71.1 ± 10.6 years. The mean baseline preoperative ejection fraction (EF) was 53.0%, with no change (P = 0.88) in the immediate postoperative EF (53.6%). A most recent follow-up EF revealed a significant increase of EF (55.2%), P = 0.01. Furthermore, there was a significant increase from peak velocity to PVMRE (mean difference [MD] ± standard error of mean (SEM) [0.15 ± 0.04], P < 0.01), an increase in pressure gradient (PGIPE) to PGMRE (MD ± SEM [1.70 ± 0.49], P < 0.01), and a decrease in Doppler velocity index (DVIIPE) to DVIMRE (MD ± SEM [-0.037 ± 0.01], P = 0.01). Regarding the SVF rate, 13 (4.8%) patients had failed valves requiring replacement throughout the study period.

Conclusions

Over a 5-year follow-up period, 4.8% had SVF with an SVD of 23.2%, with the majority of SVD not being clinically significant except in six patients. These results corroborate with a previously published study suggesting a bad clinical outcome of Trifecta valve placement.

Contemporary applications of multimodality imaging in infective endocarditis

INTRODUCTION

Infective endocarditis (IE) is an increasingly important condition with significant morbidity and mortality. With advancements in cardiovascular interventions including prosthetic valve implantation and utilization of intracardiac devices, the prevalence of IE is rising in the modern era. Early detection and management of this condition are critical.

AREAS COVERED

This review presents a contemporary review of the applications of multi-modality imaging in IE, taking a comparative approach of the various imaging modalities.

EXPERT OPINION

Transthoracic and transesophageal echocardiography are essential imaging modalities in establishing the diagnosis of IE, as well as evaluating for complications of IE. Other imaging modalities such as cardiac computed tomography and nuclear imaging play an important role as adjuvant imaging modalities for the evaluation of IE, particularly in prosthetic valve IE and cardiovascular implantable device associated IE. It is crucial to understand the strengths, weaknesses, and clinical application of each imaging modality, to improve the diagnosis, management, and outcomes of patients with IE.

Bioinspired polymeric heart valves: A combined in vitro and in silico approach

Background

Polymeric heart valves (PHVs) may address the limitations of mechanical and tissue valves in the treatment of valvular heart disease. In this study, a bioinspired valve was designed, assessed in silico, and validated by an in vitro model to develop a valve with optimum function for pediatric applications.

Methods

A bioinspired heart valve was created computationally with leaflet curvature derived from native valve anatomies. A valve diameter of 18 mm was chosen to approach sizes suitable for younger patients. Valves of different thicknesses were fabricated via dip-coating with siloxane-based polyurethane and tested in a pulse duplicator for their hydrodynamic function. The same valves were tested computationally using an arbitrary Lagrangian-Eulerian plus immersed solid approach, in which the fluid-structure interaction between the valves and fluid passing through them was studied and compared with experimental data.

Results

Computational analysis showed that valves of 110 to 200 μm thickness had effective orifice areas (EOAs) of 1.20 to 1.30 cm2, with thinner valves exhibiting larger openings. In vitro tests demonstrated that PHVs of similar thickness had EOAs of 1.05 to 1.35 cm2 and regurgitant fractions (RFs) <7%. Valves with thinner leaflets exhibited optimal systolic performance, whereas thicker valves had lower RFs.

Conclusions

Bioinspired PHVs demonstrated good hydrodynamic performance that exceeded ISO 5840-2 standards. Both methods of analysis showed similar correlations between leaflet thickness and valve systolic function. Further development of this PHV may lead to enhanced durability and thus a more reliable heart valve replacement than contemporary options.

Ultra-multiplex PCR technique to guide treatment of Aspergillus-infected aortic valve prostheses

Prosthetic valve endocarditis is a serious complication after heart valve replacement, accounting for about 20-30% of infective endocarditis (IE). Aspergillosis infection accounts for 25-30% of fungal endocarditis, and the mortality rate is 42-68%. Aspergillus IE often has negative blood cultures and lacks fever, which makes diagnosis difficult and delays antifungal therapy. Our study reported a case of IE in a patient with Aspergillus infection after aortic valve replacement. Ultra-multiplex polymerase chain reaction was used to identify Aspergillus infection and guide treatment. The purpose of this study was to enhance the understanding of the management of patients with endocarditis infected by fungi after valve replacement regarding the early detection, timely intervention, and treatment of the fungal infection to reduce the risk of death and improve the long-term survival of patients.

Scientific Evolution of Artificial Heart Valves: A Narrative Review

Cardiovascular disorders have always been the top contributors to the number of mortality occurring worldwide. But the last few decades have seen a drop in those numbers as the lives of millions of people have been saved due to ground-breaking advances in both therapeutic and surgical treatment modalities. Achieving this level of scientific glory in cardiology was a challenging feat. The credit goes to the scientists and physicians of the previous century who, despite their time's technological limitations, made discoveries and laid a solid foundation for modern medicine. Valvular complications are a major part of the global burden of cardiac diseases. The ongoing development of heart valve replacements remains a fascinating subject, as it continues to progress. Valve replacements comprise either mechanical heart valves or bioprosthetic heart valves. Both types of valves have their merits and demerits; their usage depends mostly on individual patient requirements. This article aims to review the evolution of the implantation of heart valves, and it is the objective of this article to give credit to scientists and physicians for their contributions. The article highlights the research gaps in finding more durable materials and the scope of further research in creating a heart valve that can be universally used for better patient outcomes.

Cost-Effectiveness of the Pharmacist-Managed Warfarin Therapy vs. Standard Care for Patients With Mechanical Mitral Valve Prostheses: An Egyptian Healthcare Perspective

Background

Despite warfarin therapy had been used for decades for patients with mechanical mitral valve prostheses (MMVPs), serious and life-threatening complications are still reported worldwide with a significant economic burden. This study is aimed at assessing the clinical and the cost-effectiveness of adopting pharmacist-managed warfarin therapy (PMWT) services for optimizing warfarin treatment in Egypt.

Methods

A prospective randomized trial in which 59 patients with MMVPs were randomly assigned to receive the PMWT services or the standard care and followed up for 1 year. The primary outcome was percentage time in the therapeutic range (TTR). For the cost-effectiveness analysis, a Markov cohort process model with nine mutually exclusive health states was developed from a medical provider’s perspective. A lifetime horizon was applied. All costs and outcomes were discounted at 3.5% annually.

Results

The study results revealed a significantly higher median TTR in the intervention group as compared to the control group; 96.8% [interquartile range (IQR) 77.9–100%] vs. 73.1% (52.7–95.1%), respectively, p = 0.008. A significant association between standard care and poor anticoagulation control (p = 0.021) was demonstrated by the multivariate regression analysis. For the cost-effectiveness analysis, the total cumulative quality-adjusted life-years (QALYs) and total costs per patient were 21.53 and 10.43; 436.38 and 1,242.25 United States dollar (USD) in the intervention and the control groups, respectively, with an incremental cost-effectiveness ratio (ICER) of −72.5796 for the intervention group.

Conclusion

The PMWT strategy was proven to provide a significantly better anticoagulation control and to be a cost-saving approach in Egyptian patients with MMVPs. Nevertheless, the dominance of this strategy is sustained by maintaining the therapeutic International Normalized Ratio (INR) control within the recommended range. Our findings will benefit Egyptian policy-makers who may seek novel health strategies for better resource allocation.

Clinical Trial Registration

[ClinicalTrials.gov], identifier [NCT04409613].

Mechanical versus Bioprosthetic Valve for Aortic Valve Replacement: Systematic Review and Meta-Analysis of Reconstructed Individual Participant Data

OBJECTIVES

To compare biological versus mechanical aortic valve replacement.

METHODS

We searched MEDLINE, Scopus, and Cochrane Library databases for randomized clinical trials and propensity-score matched studies published by October 14th, 2021 according to PRISMA statement. Individual patient data on overall survival were extracted. One- and two-stage survival analyses, and random-effects meta-analyses were conducted.

RESULTS

25 studies were identified, incorporating 8,721 bioprosthetic and 8,962 mechanical valves:. In the one-stage meta-analysis, mechanical valves cumulatively demonstrated decreased hazard for mortality (Hazard Ratio [HR] : 0.79, 95% Confidence interval [CI] : 0.74-0.84, p < 0.0001). Overall survival was similar between the compared arms for patients <50 years old (HR: 0.88, 95% CI : 0.71-1.1, p = 0.216), increased in the mechanical valve arm for patients 50-70 years old (HR : 0.76, 95% CI : 0.70-0.83, p < 0.0001), and increased in the bioprosthetic arm for patients >70 years old (HR : 1.35, 95% CI : 1.17-1.57, p < 0.0001). Meta-regression analysis revealed that the survival in the 50-70 years old group was not influenced by the publication year of the individual studies. No statistically significant difference was observed regarding in-hospital mortality, post-operative strokes and post-operative reoperation. All-cause mortality was found decreased in the mechanical group, cardiac mortality was comparable between the two groups, major bleeding rates were increased in the mechanical valve group, and reoperation rates were increased in the bioprosthetic valve group.

CONCLUSIONS

Survival rates seem to not be influenced by the type of prosthesis in patients <50 years old. A survival advantage in favour of mechanical valves is observed in patients 50-70 years old, while in patients >70 years old bioprosthetic valves offer better survival outcomes.

Radiation Induces Valvular Interstitial Cell Calcific Response in an in vitro Model of Calcific Aortic Valve Disease

Background: Mediastinal ionizing radiotherapy is associated with an increased risk of valvular disease, which demonstrates pathological hallmarks similar to calcific aortic valve disease (CAVD). Despite advances in radiotherapy techniques, the prevalence of comorbidities such as radiation-associated valvular disease is still increasing due to improved survival of patients receiving radiotherapy. However, the mechanisms of radiation-associated valvular disease are largely unknown. CAVD is considered to be an actively regulated disease process, mainly controlled by valvular interstitial cells (VICs). We hypothesize that radiation exposure catalyzes the calcific response of VICs and, therefore, contributes to the development of radiation-associated valvular disease.

Methods and Results: To delineate the relationship between radiation and VIC behavior (morphology, calcification, and matrix turnover), two different in vitro models were established: (1) VICs were cultured two-dimensional (2D) on coverslips in control medium (CM) or osteogenic medium (OM) and irradiated with 0, 2, 4, 8, or 16 Gray (Gy); and (2) three-dimensional (3D) hydrogel system was designed, loaded with VICs and exposed to 0, 4, or 16 Gy of radiation. In both models, a dose-dependent decrease in cell viability and proliferation was observed in CM and OM. Radiation exposure caused myofibroblast-like morphological changes and differentiation of VICs, as characterized by decreased αSMA expression. Calcification, as defined by increased alkaline phosphatase activity, was mostly present in the 2D irradiated VICs exposed to 4 Gy, while after exposure to higher doses VICs acquired a unique giant fibroblast-like cell morphology. Finally, matrix turnover was significantly affected by radiation exposure in the 3D irradiated VICs, as shown by decreased collagen staining and increased MMP-2 and MMP-9 activity.

Conclusions: The presented work demonstrates that radiation exposure enhances the calcific response in VICs, a hallmark of CAVD. In addition, high radiation exposure induces differentiation of VICs into a terminally differentiated giant-cell fibroblast. Further studies are essential to elucidate the underlying mechanisms of these radiation-induced valvular changes.

Long-Term Outcomes of the Mosaic Mitral Porcine Bioprosthesis in Japan - Results From the Japan Mosaic Valve Long-Term Multicenter Study

BACKGROUND

This study retrospectively evaluated the long-term patient outcomes and durability of the Mosaic mitral porcine bioprosthesis in the Japan Mosaic valve long-term multicenter study.Methods and Results:The medical records of 390 patients who underwent mitral valve replacement with the Mosaic bioprosthesis at 10 centers in Japan (1999-2014) were reviewed. Patient data were collected using the Research Electronic Data Capture software. Patient survival was determined using the Kaplan-Meier method. Freedom from structural valve deterioration (SVD) and valve-related reoperation and death were determined using actuarial methods. The median (interquartile range [IQR]) age of the cohort was 73 (69-77) years. The median (IQR) follow-up period was 4.83 (1.84-8.26) years. The longest follow-up period was 15.8 years. The 30-day mortality rate was 5.4%. The 12-year actuarial survival rate was 54.1±4.5%, and the freedom from valve-related death was 85.3±3.4%. The freedom from reoperation at 12 years was 74.3±5.7%. The freedom from SVD at 12 years was 81.4±6.6% for patients aged ≥65 years and 71.6±11.1% for those aged <65 years. The median (IQR) mean pressure gradient was 4.1 (3.0-6.0) and 5.6 (4.0-6.7) mmHg at 1 and 10 years, respectively. The median (IQR) effective orifice area was 1.7 (1.4-2.0) and 1.4 (1.2-1.6) cm²at 1 and 10 years, respectively.

CONCLUSIONS

The Mosaic porcine bioprosthesis offered satisfactory long-term outcomes for up to 12 years.

Multimodality imaging in the diagnosis and management of prosthetic valve endocarditis: A contemporary narrative review

Infective endocarditis is one of the leading life-threatening infections around the world. With the exponential growth in the field of transcatheter interventions and advances in specialized surgical techniques, the number of prosthetic valves and cardiac implantable devices has significantly increased. This has led to a steep rise in the number of cases of prosthetic valve endocarditis (PVE) comprising up to 30% of all cases. Clinical guidelines rely on the use of the modified Duke criteria; however, the diagnostic sensitivity of the modified Duke criteria is reduced in the context of PVE. This is in part attributed to prosthesis related artifact which greatly affects the ability of echocardiography to detect early infective changes related to PVE in certain cases. There has been increasing recognition of the roles of complementary imaging modalities and updates in international society recommendations. Prompt diagnosis and treatment can prevent the devastating consequences of this condition. Imaging modalities such as cardiac computed tomography and ¹⁸-fluorodeoxyglucose positron emission tomography/computed tomography are diagnostic tools that provide a complementary role to echocardiography in aiding diagnosis, pre-operative planning, and treatment decision-making process in these challenging cases. Understanding the strengths and limitations of these adjuvant imaging modalities is crucial for the implementation of appropriate imaging modalities in clinical practice.

Late Outcomes of Aortic Valve Replacement with Bioprosthesis and Mechanical Prosthesis

BACKGROUND

Despite constant improvement and refinement of the prostheses, the decision between mechanical and biological valves for aortic valve replacement is still controversial.

OBJECTIVE

To compare outcomes of aortic valve replacement with bioprosthesis and mechanical prosthesis.

METHODS

This was an observational, historical cohort study with review of medical records. A total of 202 patients who underwent heart valve replacement surgery between 2004 and 2008 were selected, with a mean follow-up of 10 years. The level of significance set at 5%.

RESULTS

Mean age of patients was approximately 50 years; most patients were male (70%). Overall mortality- and reoperation-free survival was significantly higher in patients with mechanical prosthesis (HR=0.33; 95%CI=0.13-0.79; p=0.013). No difference was found in late mortality between the two groups. On the other hand, the risk of reoperation was significantly higher in patients with bioprosthesis than mechanical prosthesis (HR=0.062; 95%CI=0.008-0.457; p=0.006). The risk of composite adverse events - stroke, bleeding, endocarditis, thrombosis and paravalvular leak - was similar between the groups (HR=1.20; 95%CI= 0.74-1.93; p=0.44). The risk of bleeding was significantly higher in patients with mechanical prosthesis (HR=3.65; 95%CI= 1.43-9.29; p = 0.0064), although no case of fatal bleeding was reported.

CONCLUSION

No difference in 10-year mortality was found between the groups. The risk of reoperation significantly increases with the use of bioprosthesis, especially for patients younger than 30 years. Patients with mechanical prosthesis are at increased risk of nonfatal bleeding.

Structural stability of novel composite heart valve prostheses - Fatigue and wear performance

Heart valve replacement is a very effective method to treat severe valvular stenosis or valvular insufficiency. The valve can be divided into the mechanical valve and biological valve according to the main materials of the valve leaflets. The former has good durability, but the patients need to take anticoagulants all their lives, otherwise, thrombosis will occur; the latter has good blood compatibility, and only 3-6 months of postoperative anticoagulation is required, but its durability is lower than the former. Compared with a traditional valve used materials, the fabric composite valve leaflets have both mechanical valve and biological valve advantages, i.e. it can have both good blood compatibility and excellent fatigue resistance. This material is comprised of the internal fabric layer and bilateral external polyurethane layers jointed with adhesive, and it can adjust the flexibility, wear-resistance and fatigue resistance of the valve leaflet through adjusting the thickness of the outer polyurethane protective layer, the weaving method, the fiber diameter and the surface density of the inner ultra-high molecular weight polyethylene (UHMWPE) fabric. In this article, we tested the long-term durability of a fabric composite with its property close to the valve leaflet made of bovine pericardium, to evaluate the material performance loss under long-term fatigue and the wear degree of this material with different polyurethane layer thicknesses. As many as two hundred million cycles of fatigue test and the hydrodynamic performance test before and after the fatigue test proved that the material could withstand a service life of at least five years without structural failure or functional degradation. According to the SEM images after the experiment, it can be predicted that this material can achieve a longer fatigue life.

Staphylococcus Auricularis Endocarditis: A Rare Cause of Subacute Prosthetic Valve Endocarditis with Severe Aortic Stenosis

Prosthetic valve endocarditis (PVE) represents 20% of all cases of endocarditis. Herein, we present a rare cause of PVE by Staphylococcus auricularis (S. auricularis) exhibiting features of subacute endocarditis causing severe aortic stenosis and acute myocardial infarction.

Trilayered tissue construct mimicking the orientations of three layers of a native heart valve leaflet

A tissue-engineered heart valve can be an alternative to a prosthetic valve in heart valve replacement; however, it is not fully efficient in terms of long-lasting functionality, as leaflets in engineered valves do not possess the trilayered native leaflet structure. Previously, we developed a flat, trilayered, oriented nanofibrous (TN) scaffold mimicking the trilayered structure and orientation of native heart valve leaflets. In vivo tissue engineering-a practical regenerative medicine technology-can be used to develop an autologous heart valve. Thus, in this study, we used our flat, trilayered, oriented nanofibrous scaffolds to develop trilayered tissue structures with native leaflet orientations through in vivo tissue engineering in a rat model. After 2 months of in vivo tissue engineering, infiltrated cells and their deposited collagen fibrils were found aligned in the circumferential and radial layers, and randomly oriented in the random layer of the scaffolds, i.e., trilayered tissue constructs (TTCs) were developed. Tensile properties of the TTCs were higher than that of the control tissue constructs (without any scaffolds) due to influence of fibers of the scaffolds in tissue engineering. Different extracellular matrix proteins-collagen, glycosaminoglycans, and elastin-that exist in native leaflets were observed in the TTCs. Gene expression of the TTCs indicated that the tissue constructs were in growing stage. There was no sign of calcification in the tissue constructs. The TTCs developed with the flat TN scaffolds indicate that an autologous leaflet-shaped, trilayered tissue construct that can function as a native leaflet can be developed.

Age-stratified outcomes of bioprosthetic and mechanical aortic valve replacements in an Australian cohort of 13 377 patients

OBJECTIVES

To quantify age-stratified outcomes of bioprosthetic valve (BV) and mechanical valve (MV) surgical aortic valve replacement (AVR) in Australian patients.

DESIGN

Retrospective cohort study using population-based linked hospital morbidity and mortality data.

SETTING

Public and private hospitals.

PARTICIPANTS

Patients aged 18 years and over undergoing AVR from 2001 to 2013, stratified by age (18-64 years; 65+ years).

MAIN OUTCOME MEASURES

Age-standardized index AVR rates; rates and multivariable-adjusted (age, sex, Charlson Comorbidity Index) incidence rate ratios (IRRs) for reoperation, incident cardiovascular events (hospitalization or death for acute myocardial infarction (AMI), stroke, major hemorrhage or thromboembolism) and mortality (cardiovascular and all-cause).

RESULTS

Our cohort comprised 13 377 patients, of whom 3464 (26%) were aged 18-64 years. Annual age-standardized AVR rates increased by 2.7% with BV implants increasing in both age groups. After 5 years of follow-up, patients implanted with BV had lower rates of stroke (IRR: 0.40, 95% CI 0.27 to 0.60) and hemorrhage (IRR: 0.36, 95% CI 0.26 to 0.50). Among patients 65+ years, those implanted with BV had lower rates of AMI, hemorrhage, and cardiovascular and all-cause mortality than those implanted with MV (IRR: 0.71, 95% CI 0.53 to 0.96; IRR: 0.77, 95% CI 0.62 to 0.95; IRR: 0.80, 95% CI 0.69 to 0.92 and IRR: 0.85, 95% CI 0.74 to 0.97, respectively). After 6-10 years of follow-up, reoperation rates among patients 18-64 years were markedly higher in those implanted with BV compared with MV (IRR: 5.48, 95% CI 2.38 to 12.62) and rates of AMI were lower among patients implanted with BV compared with MV (IRR: 0.49, 95% CI 0.26 to 0.94). Among patients 65+ years rates of cardiovascular and all-cause mortality remained significantly lower for patients implanted with BV compared with MV.

CONCLUSIONS

This study provides real-world evidence of AVR use and outcomes. Use of BV implants is increasing irrespective of age. Valve choice in younger patients requires thorough evaluation of patient factors influencing both short-term outcomes and longer-term risks of reoperation, stroke and hemorrhage.

Differences in mortality in patients undergoing surgery for infective endocarditis according to age and valvular surgery

Background

Infective endocarditis (IE) is associated with high mortality. Surgery may improve survival and reduce complications, but the balance between benefit and harm is difficult and may be closely related to age and type of surgical intervention. We aimed to examine how age and type of left-sided surgical intervention modified mortality in patients undergoing surgery for IE.

Methods

By crosslinking nationwide Danish registries we identified patients with first-time IE undergoing surgical treatment 2000–2017. Patients were grouped by age < 60 years, 60–75 years, and ≥ 75 years. Multivariable adjusted Cox proportional hazard analysis was used to examine factors associated with 90-day mortality.

Results

We included 1767 patients with IE undergoing surgery, 735 patients < 60 years (24.1% female), 766 patients 60–75 years (25.8% female), and 266 patients ≥75 years (36.1% female). The proportions of patients undergoing surgery were 35.3, 26.9, and 9.1% for patients < 60 years, 60–75 years, and > 75 years, respectively. Mortality at 90 days were 7.5, 13.9, and 22.3% (p < 0.001) for three age groups. In adjusted analyses, patients 60–75 years and patients ≥75 years were associated with a higher mortality, HR = 1.84 (95% CI: 1.48–2.29) and HR = 2.47 (95% CI: 1.88–3.24) as compared with patients < 60 years. Factors associated with 90-day mortality were: mitral valve surgery, a combination of mitral and aortic valve surgery as compared with isolated aortic valve surgery, age, diabetes, and prosthetic heart valve implantation prior to IE admission.

Conclusions

In patients undergoing surgery for IE, mortality increased significantly with age and 1 in 5 died above age 75 years. Mitral valve surgery as well as multiple valve interventions augmented mortality further.

Anisotropic Fiber-Reinforced Glycosaminoglycan Hydrogels for Heart Valve Tissue Engineering

This study investigates polymer fiber-reinforced protein-polysaccharide-based hydrogels for heart valve tissue engineering applications. Polycaprolactone and gelatin (3:1) blends were jet-spun to fabricate aligned fibers that possessed fiber diameters in the range found in the native heart valve. These fibers were embedded in methacrylated hydrogels made from gelatin, sodium hyaluronate, and chondroitin sulfate to create fiber-reinforced hydrogel composites (HCs). The fiber-reinforced gelatin glycosaminoglycan (GAG)-based HC possessed interconnected porous structures and porosity higher than fiber-only conditions. These fiber-reinforced HCs exhibited compressive modulus and biaxial mechanical behavior comparable to that of native porcine aortic valves. The fiber-reinforced HCs were able to swell higher and degraded less than the hydrogels. Elution studies revealed that less than 20% of incorporated gelatin methacrylate and GAGs were released over 2 weeks, with a steady-state release after the first day. When cultured with porcine valve interstitial cells (VICs), the fiber-reinforced composites were able to maintain higher cell viability compared with fiber-only samples. Quiescent VICs expressed alpha smooth muscle actin and calponin showing an activated phenotype, along with a few cells expressing the proliferation marker Ki67 and negative expression for RUNX2, an osteogenic marker. Our study demonstrated that compared with the hydrogels and fibers alone, combining both components can yield durable, reinforced composites that mimic heart valve mechanical behavior, while maintaining high cell viability and expressing positive activation as well as proliferation markers.

Incidence and factors associated with infective endocarditis in patients undergoing left-sided heart valve replacement

Aims

Patients with left-sided heart valve replacement are considered at high-risk of infective endocarditis (IE). However, data on the incidence and risk factors associated with IE are sparse.

Methods and results

Through Danish administrative registries, we identified patients who underwent left-sided heart valve replacement from January 1996 to December 2015. Patients were categorized in mitral and aortic valve replacement (MVR and AVR) and followed until: 12 years after valve surgery, end of study, death, emigration, or hospitalization due to IE, whichever came first. Multivariable adjusted Cox proportional hazard analysis was used to investigate which baseline characteristics were associated with IE. A total of 18 041 patients were included. The cumulative IE risk at 10 years follow-up was 5.2% in both MVR and AVR patients. In patients with MVR, male sex [hazard ratio (HR) = 1.68, 95% confidence interval (95% CI) 1.06-2.68], bioprosthetic valve (HR = 1.91, 95% CI 1.08-3.37), and heart failure (HR = 1.69, 95% CI 1.06-2.68) were among factors associated with an increased risk of IE. In AVR patients, male sex (HR = 1.59, 95% CI 1.33-1.89), bioprosthetic valve (HR = 1.70, 95% CI 1.35-2.15), and cardiac implantable electronic device (CIED) (HR = 1.57, 95% CI 1.19-2.06) were among factors associated with an increased risk of IE.

Conclusion

Infective endocarditis after left-sided heart valve replacement is not uncommon and occurs in about 1/20 over 10 years. Male, bioprosthetic valve, and heart failure were among factors associated with IE in MVR patients while male, bioprosthetic valve, and CIED were among factors associated with IE in AVR patients.

Short-Term Clinical Follow-Up After Thrombolytic Therapy in Patients With Prosthetic Valve Thrombosis: A Single-Center Experience

Background

Thrombolytic therapy has evolved as an alternative to surgery for prosthetic valve thrombosis (PVT). Therefore, this retrospective, single-center study aimed to evaluate the clinical profile of PVT and the role of thrombolytic therapy in patients with PVT.

Methods

Data from a total of 16 consecutive patients with PVT enrolled between January 2017 and January 2018 at a tertiary care center in India were retrospectively evaluated. PVT was diagnosed based on clinical presentation, transthoracic echocardiography, and fluoroscopy. All patients received 0.25 MU intravenous (IV) bolus streptokinase over 30 min, followed by a 0.1 MU/h IV infusion for a maximum of 72 h. Transthoracic echocardiography and fluoroscopy were repeated after completion of thrombolysis session. The clinical endpoints were death and hemodynamic success within 24 h of thrombolytic therapy or during the hospital stay, and major complications, including stroke or major bleeding (intracranial bleed or bleeding requiring transfusion or surgical treatment) during the hospital stay and within 3 months of thrombolytic therapy.

Results

The median age of the patients was 40 ± 11.60 years and about 62.5% (n = 10) were females. The median time between the valve placement and presentation for PVT was 3 years (range: 1 - 4 years). The peak gradient across the thrombotic mitral and aortic valve was 43.79 ± 18.47 and 93.5 ± 33.11 mmHg, respectively. At 3 days post-thrombolysis, peak gradient across both mitral valve (15.91 ± 7.56; mean gradient: 8.45 ± 4.01) and aortic valve (23.50 ± 6.45; mean gradient: 13.60 ± 3.83) decreased significantly (P ≤ 0.05). The thrombolytic therapy was successful in 13 (81.25%) patients. While, two (12.50%) patients died, none developed stroke or myocardial infarction during the study period.

Conclusions

The present study with short-term follow-up demonstrated the acceptable clinical efficacy of thrombolytic therapy. However, larger trials with a greater number of patients and longer follow-up are warranted to establish the safety and effectiveness of thrombolytic therapy in patients with PVT.

An overlooked fact: thrombocytopenia following bioprosthetic aortic valve replacement

Introduction

Thrombocytopenia observed after bioprosthetic aortic valve replacement has remained a puzzle to solve.

Aim

To analyze thrombocytopenia occurring after bioprosthetic aortic valve replacement by comparison to mechanical aortic valve replacement and coronary artery bypass grafting procedures.

Material and methods

The study was conducted retrospectively on a total of 297 patients who underwent bioprosthetic aortic valve replacement, mechanical prosthetic aortic valve replacement and coronary artery bypass grafting at the cardiovascular surgery department of our clinical center between January 2013 and September 2017. Preoperative and postoperative first 14-day thrombocyte levels of the patients were analyzed.

Results

The postoperative blood thrombocyte level decrease was found to be more significant in patients who underwent bioprosthetic aortic valve replacement than in patients who underwent mechanical aortic valve replacement and coronary artery bypass grafting (p < 0.01). There was also a statistically significant difference in the time to reach the lowest postoperative platelet levels according to type of surgery (p = 0.001; p < 0.01).

Conclusions

When compared to the patients who underwent coronary artery bypass grafting and mechanical prosthetic aortic valve replacement, postoperative thrombocytopenia was found to be more severe in patients who underwent bioprosthetic aortic valve replacement, with a dramatic decrease in thrombocyte count being observed on the postoperative second day. It was found that the thrombocytopenia recovers without causing any problem. We think that the shear forces may play a role in this recovery through washout of chemicals responsible for thrombocytopenia from the glutaraldehyde treated bioprostheses.

Comparison of Biological and Mechanical Prostheses for Heart Valve Surgery: A Systematic Review of Randomized Controlled Trials

Background

The choice of a mechanical (MP) or biological prosthesis (BP) for patients with valvular heart disease undergoing replacement is still not a consensus.

Objective

We aimed to determine the clinical outcomes of MP or BP placement in those patients.

Methods

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that compared biological prostheses and mechanical prostheses in patients with valvular heart diseases and assessed the outcomes. RCTs were searched in the MEDLINE, EMBASE, LILACS, CENTRAL, SCOPUS and Web of Science (from inception to November 2014) databases. Meta-analyses were performed using inverse variance with random effects models. The GRADE system was used to rate the quality of the evidence. A P-value lower than 0.05 was considered significant.

Results

A total of four RCTs were included in the meta-analyses (1,528 patients) with follow up ranging from 2 to 20 years. Three used old generation mechanical and biological prostheses, and one used contemporary prostheses. No significant difference in mortality was found between BP and MP patients (risk ratio (RR = 1.07; 95% CI 0.99-1.15). The risk of bleeding was significantly lower in BP patients than MP patients (RR = 0.64; 95% CI 0.52-0.78); however, reoperations were significantly more frequent in BP patients (RR = 3.60; 95% CI 2.44-5.32). There were no statistically significant differences between BP and MP patients with respect to systemic arterial embolisms and infective endocarditis (RR = 0.93; 95% CI 0.66-1.31, RR = 1.21; CI95% 0.78-1.88, respectively). Results in the trials with modern and old prostheses were similar.

Conclusions

The mortality rate and the risk of thromboembolic events and endocarditis were similar between BP and MP patients. The risk of bleeding was approximately one third lower for BP patients than for MP patients, while the risk of reoperations was more than three times higher for BP patients.

Prosthetic valve endocarditis - A trouble or a challenge?

Prosthetic valve endocarditis (PVE) represents a rare and serious complication of valve replacement associated with high morbidity and mortality, which significantly differs from native valve endocarditis (NVE). There are two major problems: establishing diagnosis and treatment of PVE. Diagnosis in PVE is challenging and often requires several imaging methods besides standard microbiological analyzes. Transesophageal echocardiographic examination remains the widely used imaging technique in PVE diagnosis, but additional techniques such as computed tomography (CT) and ¹⁸F-fluodeoxyglucose positron emission tomography/CT are often necessary. Persistent fever, embolic complications, valve dehiscence, intracardial abscess, heart failure, as well as staphylococcal and fungal PVE require surgical treatment to avoid lethal outcome. The introduction of transcatheter valve implantations and devices significantly complicated the approach - diagnostic and therapeutic to PVE patients. Despite constantly increasing knowledge regarding pathogenesis and treatment of PVE, the optimal therapy remains a matter of debate. Additional studies are necessary to define therapeutic strategies for this potentially fatal complication.

Transcatheter Aortic Valve-in-Valve Procedure in Patients with Bioprosthetic Structural Valve Deterioration

Surgical aortic valve replacement is the gold standard procedure to treat patients with severe, symptomatic aortic valve stenosis or insufficiency. Bioprosthetic valves are used for surgical aortic valve replacement with a much greater prevalence than mechanical valves. However, bioprosthetic valves may fail over time because of structural valve deterioration; this often requires intervention due to severe bioprosthetic valve stenosis or regurgitation or a combination of both. In select patients, transcatheter aortic valve replacement is an alternative to surgical aortic valve replacement. Transcatheter valve-in-valve (ViV) replacement is performed by implanting a transcatheter heart valve within a failing bioprosthetic valve. The transcatheter ViV operation is a less invasive procedure compared with reoperative surgical aortic valve replacement, but it has been associated with specific complications and requires extensive preoperative work-up and planning by the heart team. Data from experimental studies and analyses of results from clinical procedures have led to strategies to improve outcomes of these procedures. The type, size, and implant position of the transcatheter valve can be optimized for individual patients with knowledge of detailed dimensions of the surgical valve and radiographic and echocardiographic measurements of the patient's anatomy. Understanding the complexities of the ViV procedure can lead surgeons to make choices during the original surgical valve implantation that can make a future ViV operation more technically feasible years before it is required.

Fabrication and In Vitro Characterization of a Tissue Engineered PCL-PLLA Heart Valve

Heart valve diseases are among the leading causes of cardiac failure around the globe. Nearly 90,000 heart valve replacements occur in the USA annually. Currently, available options for heart valve replacement include bioprosthetic and mechanical valves, both of which have severe limitations. Bioprosthetic valves can last for only 10-20 years while patients with mechanical valves always require blood-thinning medications throughout the remainder of the patient's life. Tissue engineering has emerged as a promising solution for the development of a viable, biocompatible and durable heart valve; however, a human implantable tissue engineered heart valve is yet to be achieved. In this study, a tri-leaflet heart valve structure is developed using electrospun polycaprolactone (PCL) and poly L-lactic acid (PLLA) scaffolds, and a set of in vitro testing protocol has been developed for routine manufacturing of tissue engineered heart valves. Stress-strain curves were obtained for mechanical characterization of different valves. The performances of the developed valves were hemodynamically tested using a pulse duplicator, and an echocardiography machine. Results confirmed the superiority of the PCL-PLLA heart valve compared to pure PCL or pure PLLA. The developed in vitro test protocol involving pulse duplicator and echocardiography tests have enormous potential for routine application in tissue engineering of heart valves.

Reversible bioprosthetic valve thrombosis from eosinophilia

A 31-year-old man with a mitral bioprosthetic valve presented with recent worsening of exertional dyspnoea 7 years after the mitral valve replacement. Evaluation revealed an increased gradient across the thickened mitral bioprosthetic valve leaflets. Marked eosinophilia was present and was considered as a putative cause for bioprosthetic valve thrombosis. The treatment with systemic corticosteroids and oral anticoagulation led to complete resolution of symptoms with significant decrease in mitral bioprosthetic valve gradient and leaflet thinning. The case is reported to highlight the fact that eosinophilia may cause reversible bioprosthetic valve thrombosis.

Recurrent Hemorrhagic Conversion of Ischemic Stroke in a Patient with Mechanical Heart Valve: A Case Report and Literature Review

The authors present a unique case of recurrent stroke, discovered to be secondary to hemorrhagic conversion of microemboli from a mechanical aortic valve despite anticoagulation with Coumadin. The complexity of this case was magnified by the patient’s young age, a mechanical heart valve (MHV), and a need for anticoagulation to maintain MHV patency in a setting of potentially life-threatening intracranial hemorrhage. Anticoagulant and antiplatelet therapy are risk factors for hemorrhagic conversion post-cerebral ischemia; however, the pathophysiology underlying endothelial cell dysfunction causing red blood cell extravasation is an active area of basic and clinical research. The need for randomized clinical trials to aid in the creation of standardized treatment protocol continues to go unmet. Consequently, there is marked variation in therapeutic approaches to treating intracranial hemorrhage in patients with an MHV. Unfortunately, patients with an MHV are considered at high thromboembolic (TE) risk, and these patients are often excluded from clinical trials of acute stroke due to their increased TE potential. The authors feel this case represents an example of endothelial dysfunction secondary to microthrombotic events originating from an MHV, which caused ischemic stroke with hemorrhagic conversion complicated by the need for anticoagulation for an MHV. This case offers a definitive treatment algorithm for a complex clinical dilemma.

Developing a Clinically Relevant Tissue Engineered Heart Valve-A Review of Current Approaches

Tissue engineered heart valves (TEHVs) have the potential to address the shortcomings of current implants through the combination of cells and bioactive biomaterials that promote growth and proper mechanical function in physiological conditions. The ideal TEHV should be anti-thrombogenic, biocompatible, durable, and resistant to calcification, and should exhibit a physiological hemodynamic profile. In addition, TEHVs may possess the capability to integrate and grow with somatic growth, eliminating the need for multiple surgeries children must undergo. Thus, this review assesses clinically available heart valve prostheses, outlines the design criteria for developing a heart valve, and evaluates three types of biomaterials (decellularized, natural, and synthetic) for tissue engineering heart valves. While significant progress has been made in biomaterials and fabrication techniques, a viable tissue engineered heart valve has yet to be translated into a clinical product. Thus, current strategies and future perspectives are also discussed to facilitate the development of new approaches and considerations for heart valve tissue engineering.

[Transcatheter aortic valve thrombosis]

GOALS

Transcatheter aortic valve or leaflets thrombosis are mainly misapprehended. It negatively impacts the long-term efficiency of such prosthesis. Moreover, its incidence is presumably higher than previously described.

EPIDEMIOLOGY

Recently reported subclinical leaflet thrombosis, occurring between first to third months after implantation, is about 10to 15%. All prosthesis are concerned by potential thrombosis.

DIAGNOSIS

Transcatheter aortic valve thrombosis is usually detected on the basis of increased transvalvular pressure gradients or symptoms at routine follow-up. Main causes of post-TAVI thrombosis are: elderly patients, incomplete TAVI expansion, incomplete TAVI apposition to the aortic wall, areas of diminished blood flow and stagnation around the prosthesis. Main risk-factors of thrombosis are: large valves, patients with ejection fraction lower than 35%, valve-in-valve implantation, males, patients with large sinus of Valsalva, patients without anticoagulants.

TREATMENT

Post-TAVI anti thrombotic regimen remains empirical. It is based on aspirin alone or dual antiplatelet therapy for 1-6months, followed by aspirin for life. Symptomatic patients with thrombus-based valve dysfunction are to be treated by oral anticoagulation (i.e., VKA or new oral anticoagulants NOAC). This treatment allows the restoration of normal leaflet motion in patients with a median time of 14 days.

Hydrodynamic Assessment of Aortic Valves Prepared from Porcine Small Intestinal Submucosa

Infants and children born with severe cardiac valve lesions have no effective long term treatment options since currently available tissue or mechanical prosthetic valves have sizing limitations and no avenue to accommodate the growth of the pediatric patient. Tissue engineered heart valves (TEHVs) which could provide for growth, self-repair, infection resistance, and long-term replacement could be an ideal solution. Porcine small intestinal submucosa (PSIS) has recently emerged as a potentially attractive bioscaffold for TEHVs. PSIS may possess the ability to recruit endogenous cardiovascular cells, leading to phenotypically-matched replacement tissue when the scaffold has completely degraded. Our group has successfully implanted custom-made PSIS valves in 4 infants with critical valve defects in whom standard bioprosthetic or mechanical valves were not an option. Short term clinical follow-up has been promising. However, no hydrodynamic data has been reported to date on these valves. The purpose of this study was to assess the functional effectiveness of tri-leaflet PSIS bioscaffolds in the aortic position compared to standard tri-leaflet porcine bioprosthetic valves. Hydrodynamic evaluation of acute PSIS function was conducted using a left heart simulator in our laboratory. Our results demonstrated similar flow and pressure profiles (p > 0.05) between the PSIS valves and the control valves. However, forward flow energy losses were found to be significantly greater (p < 0.05) in the PSIS valves compared to the controls possibly as a result of stiffer material properties of PSIS relative to glutaraldehyde-fixed porcine valve tissue. Our findings suggest that optimization of valve dimensions and shape may be important in accelerating de novo valve tissue growth and avoidance of long-term complications associated with higher energy losses (e.g. left ventricular hypertrophy). Furthermore, long term animal and clinical studies will be needed in order to conclusively address somatic growth potential of PSIS valves.

Degradable Chitosan-Collagen Composites Seeded with Cells as Tissue Engineered Heart Valves

BACKGROUND

Degradable collagen-chitosan composite materials have been used to fabricate tissue engineered heart valves. The aims of this study were to demonstrate that the collagen-chitosan composite scaffolds are cytocompatible, and endothelial cells can be differentiated from bone marrow mesenchymal stem cells (BMSCs) when seeded onto the scaffolds. The adhesion and biological activities of the seeded cells were also investigated.

METHODS

Collagen-chitosan composite material was used as the cell matrix, and smooth muscle cells, fibroblasts and BMSCs were used as seed cells. After four weeks of in vitro culture, the smooth muscle cells, fibroblasts, and BMSCs were sequentially seeded into the collagen-chitosan composite material. After four weeks in culture, the cellular density and activity were assessed on segments of the tissue engineered heart valve scaffolds to determine the cell viability and proliferation in the collagen-chitosan composite material.

RESULTS

The tissue engineered heart valves stained positively for both smooth muscle actin and endothelial cell factor VIII, suggesting that the seeded cells were in fact smooth muscle cells, fibroblasts, and endothelial cells. The 6-ketone prostaglandin content, as measured by radioimmunoassay, of the collagen-chitosan cell culture fluid was higher than that of the serum-free medium (P <0.01). Light and electron microscopy showed that the seeded cells had shapes similar to the morphology of smooth muscle cells, fibroblasts, and endothelial cells.

CONCLUSIONS

Endothelial cells can be differentiated from BMSCs when seeded onto the collagen-chitosan composite scaffolds. The seeded cells retained their biological activity after being cultured in vitro and seeded into the collagen-chitosan composite material.

Late Mortality and Morbidity in Elderly Patients with Mechanical Heart Valves

A retrospective study was performed in patients under and over 65 years old implanted with a mechanical valve, to compare late mortality and morbidity. Of 381 patients who underwent mechanical valve replacement at Nagoya University in the 1990s, 357 (11 hospital deaths and 13 lost to follow-up; 96.4% follow-up rate) were followed up for 7.9 ± 3.3 years (2,811 patient-years). They were divided into two groups either side of 65 years of age at operation. The young and elderly patient groups contained 275 and 82 patients, respectively. The survival rate in the young group was 96.1% (95% confidence interval, 93.7%–98.5%) at 5 years and 92.0% (95% confidence interval, 88.3%–95.7%) at 10 years, which was significantly better than 88.0% (95% confidence interval, 80.6%–95.4%) at 5 years and 73.8% (95% confidence interval, 66.2%–85.4%) at 10 years in the elderly group. The two groups did not differ significantly in the incidence of thromboembolic events, bleeding events, endocarditis, or reoperation. We are also encouraged by the fact that mechanical valves are not a risk factor for late mortality or morbidity, even in elderly patients.

Approach to the analysis of cardiac valve prostheses as surgical pathology or autopsy specimens

Pathologists are likely to encounter substitute heart valves with increasing frequency. Informed evaluation of such valves provides valuable information that contributes to both patient care and our understanding of the pathobiology of host interactions with mechanical devices. This article summarizes the most important considerations underlying such analyses-including valve identification, common morphologic features and modes of failure, technical details of evaluation, and potential pitfalls.

Left ventricular hypertrophy in valvular aortic stenosis: mechanisms and clinical implications

Valvular aortic stenosis is the second most prevalent adult valve disease in the United States and causes progressive pressure overload, invariably leading to life-threatening complications. Surgical aortic valve replacement and, more recently, transcatheter aortic valve replacement effectively relieve the hemodynamic burden and improve the symptoms and survival of affected individuals. However, according to current American College of Cardiology/American Heart Association guidelines on the management of valvular heart disease, the indications for aortic valve replacement, including transcatheter aortic valve replacement, are based primarily on the development of clinical symptoms, because their presence indicates a dismal prognosis. Left ventricular hypertrophy develops in a sizeable proportion of patients before the onset of symptoms, and a growing body of literature demonstrates that regression of left ventricular hypertrophy resulting from aortic stenosis is incomplete after aortic valve replacement and associated with adverse early postoperative outcomes and worse long-term outcomes. Thus, reliance on the development of symptoms alone without consideration of structural abnormalities of the myocardium for optimal timing of aortic valve replacement potentially constitutes a missed opportunity to prevent postoperative morbidity and mortality from severe aortic stenosis, especially in the face of the quickly expanding indications of lower-risk transcatheter aortic valve replacement. The purpose of this review is to discuss the mechanisms and clinical implications of left ventricular hypertrophy in severe valvular aortic stenosis, which may eventually move to center stage as an indication for aortic valve replacement in the asymptomatic patient.