Biological Prosthetic Valves Research Articles

Tissue-Engineered Heart Valves: A Call for Mechanistic Studies.

Heart valve disease carries a substantial risk of morbidity and mortality. Outcomes are significantly improved by valve replacement, but currently available mechanical and biological replacement valves are associated with complications of their own. Mechanical valves have a high rate of thromboembolism and require lifelong anticoagulation. Biological prosthetic valves have a much shorter lifespan, and they are prone to tearing and degradation. Both types of valves lack the capacity for growth, making them particularly problematic in pediatric patients. Tissue engineering has the potential to overcome these challenges by creating a neovalve composed of native tissue that is capable of growth and remodeling. The first tissue-engineered heart valve (TEHV) was created more than 20 years ago in an ovine model, and the technology has been advanced to clinical trials in the intervening decades. Some TEHVs have had clinical success, whereas others have failed, with structural degeneration resulting in patient deaths. The etiologies of these complications are poorly understood because much of the research in this field has been performed in large animals and humans, and, therefore, there are few studies of the mechanisms of neotissue formation. This review examines the need for a TEHV to treat pediatric patients with valve disease, the history of TEHVs, and a future that would benefit from extension of the reverse translational trend in this field to include small animal studies.

In vitro study of a biological prosthetic valve for seamless fixation

Aim: to evaluate the manipulative properties of the system being developed for cardiac valve re-operation on an in vitro bovine heart model.Material and methods. The prototype of the prosthesis being developed, mounted on the implant holder, as well as the dilatation balloon of its own design, were used as the objects of the study. The bioprosthesis «UniLine» of 21 mm size for the aortic position was chosen as the target site of implantation, which was established by the «classical» suture method. After that, the implantation of the tested device was carried out as a «valve in valve» and the quality of the installation and the combined operation of all the components of the re-prosthesis system were evaluated.Results. The test implantation demonstrated the consistency of the proposed method on the basis of balloon seamless fi xation, as well as high ergonomic characteristics: the average time of seamless implantation of the developed prototype on an in vitro animal heart model was 3 minutes versus the implantation of the «UniLine» bioprosthesis – 11 min, Implantation provided a reliable prosthesis The breaking force was 12.9 N, which is equivalent to a pressure of 279 mm Hg.

Providencia stuartii Aortic Prosthetic Valve Endocarditis with Formation of Paravalvular Pseudoaneurysm

Infective endocarditis (IE) is characterized by high morbidity and mortality. Providencia stuartii infections are very rare and mainly acquired in a hospital setting, being isolated primarily in urine cultures of patients with longterm urinary catheters; rarely causing bacteremia and endocarditis. The authors present a case of a 74-year-old male patient with vascular risk factors and a biological aortic prosthetic valve hospitalized for urosepsis with P. stuartii bacteremia. He underwent antibiotic susceptibility-guided therapy, resulting in both negative urine and blood cultures. However, the patient was later re-admitted due to persistent P. stuartii urosepsis and bacteremia. A transesophageal echocardiogram revealed endocarditis of the prosthetic aortic valve, complicated with extensive aortic root pseudoaneurysm, fistulized into the left atrium. Given the co-comorbidities and extent of the disease, he was not a candidate for surgical intervention and therefore maintained broad-spectrum antibiotic therapy. Unfortunately, the patient didn’t respond to best medical treatment and died of septic shock.

Mortality Predictors in the Surgical Treatment of Active Infective Endocarditis.

IntroductionActive infective endocarditis is associated with high morbidity and mortality. Surgery is indicated in high-risk conditions, and the main determinants of mortality in surgical treatment should be evaluated.ObjectiveTo identify mortality predictors in the surgical treatment of active infective endocarditis in a long-term follow-up.MethodsThis prospective observational study involved 88 consecutive patients diagnosed with active infective endocarditis, who underwent surgery between January 2005 and December 2015. Fifty-eight (65.9%) patients were male, the mean age was 50.87±16.15 years. A total of 31 (35.2%) patients had a history of rheumatic fever; 48 (54.5%) had had heart surgery with prosthetic valve implantation; 45 (93.8%) had biological prosthetic valve endocarditis and 3 (6.3%) mechanical prosthetic valve; 40 (45.5%) patients had the disease in their native valve. The mean EuroSCORE II was 8.9±6.5%, and the main surgical indication was refractory heart failure in 38 (43.2%) patients. A total of 68 bioprosthesis (36 aortic, 32 mitral) and 29 mechanical prostheses (12 aortic, 17 mitral) were implanted and three mitral valve plasties performed. A total of 25 (28.4%) patients underwent double or triple valve procedures. Aortic annulus reconstruction by abscess was performed in 18 (20.5%) and six (6.81%) patients had combined procedure. The mean surgery time was 359±97.6 minutes.ResultsThe overall survival in up to a 10-year follow-up period was 79.5%. In the univariate analysis, the main mortality predictors were positive blood cultures (P=0.003), presence of typical microorganisms (P=0.008), most frequently Streptococcus viridans (12 cases; 25%); C-reactive protein (hazard ratio [HR] 1.034, 95% confidence interval [CI] 1.000 to 1.070, P=0.04); creatinine clearance (HR 0.977, 95% CI 0.962 to 0.993, P=0.005); length of surgery: every five minutes multiplies the chance of death 1.005-fold (HR 1.005, 95% CI 1.001 to 1.009, P=0.0307); age (HR 1.060, 95% CI 1.026 to 1.096, P=0.001); and EuroSCORE II (HR 1.089, 95% CI 1.030 to 1.151, P=0.003).ConclusionA positive blood culture with typical microorganism, C-reactive protein, age, EuroSCORE II, total surgical time and the presence of postoperative complications were the major predictors of mortality and significantly impacted survival in up to a 10-year follow-up period.

Percutaneous Closure of a Left Ventricular Pseudoaneurysm Causing Recurrent Embolization, With Cerebral Protection and Extracorporeal Membrane Oxygenation Support

A 65-year-old man with a history of inferolateral wall myocardial infarction (MI), complicated by massive mitral regurgitation, treated with biological prosthetic valve implantation (St. Jude Epic 27 mm, St. Jude Medical, St. Paul, Minnesota) and Dacron-patch ventricular repair, was admitted to our

Analytical approach on leaflet flutter on biological prosthetic heart valves

Biological prosthetic valves are known for having good hemodynamics and resistance to clot formation, but they also have the disadvantage of possessing a short lifespan. An understudied effect is the fluttering of cusps, which is associated with calcification, hemolysis, and fatigue. The present study used a mathematical model of eigenvalues calculation to predict the critical speed of flutter onset in porcine and bovine pericardium valves, comparing the results with experiments on a test bench. Most results were below the speeds found experimentally, an outcome usually found in other flutter analytical theories. The analytical method demonstrated that pericardial valves have greater resistance to the onset of flutter than porcine valves, which agrees with experimental results. The sensitivity analysis showed that the internal diameter has a high impact on the critical speed, while thickness has greater importance when considering critical flow. The same analysis demonstrated that the higher thickness and elastic modulus values of pericardial valves explain why it has an increased resistance to cusps oscillation in comparison with porcine. The mathematical model in this paper is the first flutter analytical theory focused on heart valves. It can assist in new bioprosthesis projects that can be more resistant to oscillations and early fatigue failure.

Quantification and Analysis of Leaflet Flutter on Biological Prosthetic Cardiac Valves.

The use of porcine or bovine pericardium biological cardiac valves has as its main disadvantage a relatively short lifespan, with failures due to calcification and fatigue. Increasing these valves' durability constitutes a great challenge. An understudied phenomenon is the effect of flutter, an oscillation of the leaflets that can cause regurgitation and accelerate calcification and fatigue. As a starting point to study how to reduce or prevent these oscillations, a method was developed to quantify the flutter frequencies occurring at the point of the valve's full opening. On a test bench that simulates the heart flow, the cusp behaviors of eight biological valves were filmed with a high speed camera at 2000 frames per second at different flow rates and motion capture software obtained the frequencies and amplitudes of the vibrations of each leaflet. Oscillations in the range of 200 Hz with average amplitudes of 0.4 mm were found; larger nominal diameter valves obtained lower values, and bovine pericardial valves had superior performance compared to porcine valves. A dimensionless analysis was performed to find a relationship between the geometric and mechanical properties of the valves with the critical speed of the onset of fluttering. This relationship inspired a method to predict whether flutter will occur in the bioprosthesis. This method is a new tool for the consideration of maximizing the life of prosthetic valves.

Postoperative residua and sequelae in adults with repaired tetralogy of Fallot.

Postoperative residua and sequelae after repair of tetralogy of Fallot in adults became one of the major concerns in the field of adult congenital heart disease. Right heart failure and arrhythmia can result fatal, and are considered to be related dilated right ventricle due to pulmonary valve regurgitation. Although precise indication of pulmonary valve replacement (PVR) is still not established, right ventricular end-diastolic volume index less than 150-170ml/m(2) and right ventricular end systolic volume index less than 82-90ml/m(2) may be border line for RV remodeling after PVR. Biological prosthetic valve is generally used at the pulmonary position.

Three-dimensional transesophageal echocardiography in the diagnosis of biological prosthetic valve thrombosis (and its resolution)

Three-dimensional transesophageal echocardiography in the diagnosis of biological prosthetic valve thrombosis (and its resolution)

Three-dimensional transesophageal echocardiography in the diagnosis of biological prosthetic valve thrombosis (and its resolution)

Three-dimensional transesophageal echocardiography in the diagnosis of biological prosthetic valve thrombosis (and its resolution)

Nontuberculous Mycobacteria: An Underestimated Cause of Bioprosthetic Valve Infective Endocarditis.

Background. Atypical mycobacteria, or nontuberculous mycobacteria (NTM), have been barely reported as infective endocarditis (IE) agents. Methods. From January 2010 to December 2013, cardiac valve samples sent to our laboratory as cases of blood culture-negative suspected IE were analyzed by 16S rDNA polymerase chain reaction (PCR). When positive for NTM, hsp PCR allowed species identification. Demographic, clinical, echocardiographic, histopathological, and Ziehl-Neelsen staining data were then collected. Results. Over the study period, 6 of 370 cardiac valves (belonging to 5 patients in 3 hospitals) were positive for Mycobacterium chelonae (n = 5) and Mycobacterium lentiflavum (n = 1) exclusively on bioprosthetic material. The 5 patients presented to the hospital for heart failure without fever 7.1-18.9 months (median 13.1 months) after biological prosthetic valve implantation. Echocardiography revealed paravalvular regurgitation due to prosthesis dehiscence in all patients. Histopathological examination of the explanted material revealed inflammatory infiltrates in all specimens, 3 of which were associated with giant cells. Gram staining and conventional cultures remained negative, whereas Ziehl-Neelsen staining showed acid-fast bacilli in all patients. Allergic etiology was ruled out by antiporcine immunoglobulin E dosages. These 5 cases occurred exclusively on porcine bioprosthetic material, revealing a statistically significant association between bioprosthetic valves and NTM IE (P < .001). Conclusions. The body of evidence confirmed the diagnosis of prosthetic IE. The statistically significant association between bioprosthetic valves and NTM IE encourages systematic Ziehl-Neelsen staining of explanted bioprosthetic valves in case of early bioprosthesis dysfunction, even without an obvious sign of IE. In addition, we strongly question the cardiac bioprosthesis conditioning process after animal sacrifice.

Catheter ablation for atrial fibrillation after an unsuccessful surgical ablation and biological prosthetic mitral valve replacement: A pilot study

BackgroundPatients with mitral valve (MV) disease and atrial fibrillation (AF) undergo simultaneous prosthetic valve replacement and radiofrequency (RF) ablation procedure; however, this combinational procedure restores sinus rhythm (SR) in only 68–82% of the cases. In patients with ineffective surgical ablation, the use of a biological prosthetic valve might not only be a good choice to perform safe catheter ablation procedure in the left atrium (LA), but also provide a way to discontinue administration of oral anticoagulants. The objective of this study was to assess the efficacy of catheter ablation for AF after MV replacement with a biological prosthesis and an ineffective surgical ablation procedure. MethodsTen consecutive patients aged 48 ± 7 years were enrolled in this study. All patients had long-persistent AF associated with a rheumatic valve disease, which was treated by MV replacement with a biological prosthesis and a surgical RF ablation procedure. In the late postoperative period, all the patients had recurrent hemodynamically significant AF, which required repeated cardioversions. From 1 year to 3 years after the surgery, catheter ablation was performed, including reisolation of pulmonary veins (PVs) with the ablation of ganglionic plexi or linear lesions on the roof of the LA and mitral isthmus. The efficacy was assessed at 3 months, 6 months, and 12 months after the procedure. ResultsRestoration of SR during ablation was achieved in all of the cases. In 6–9 months, all the patients were free of arrhythmia. LA stunning manifested by the absence or decrease of the “A” wave in the transmitral flow and the retrograde wave in the PV flow was observed in nine patients with SR. In five of the patients, LA contractile function was restored in 1–6 months. Prosthetic valve dysfunction was not detected in any of the patients. ConclusionCatheter ablation is an effective method for AF treatment following an ineffective surgical RF ablation procedure and biological prosthetic MV replacement. The use of bioprosthetic MVs allows for performing safe catheter ablation without subsequent prosthetic dysfunction.

Tricuspid Valve Infective Endocarditis In Drug Abusers: Clinical Features and Results of Surgical Treatment

The objective of this study was to evaluate the clinical features, diagnostic criteria and indications for surgery in patients – drug abusers with tricuspid valve infective endocarditis (TVIE), and outcome of surgical treatment in these patients. From December 1999 to August 2009 35 patients (drug addicts) with TVIE were operated in the department of acquired heart diseases of Cardiac and Vascular Surgery Center, Nizhny Novgorod. 25 males and 10 females aged from 15 to 51 years were included in this study. 3 patients were re-operated due to recurrence of endocarditis. Biological prosthetic valve "Bio-Lab" was used in all patients. Intravenous drug abuse was the cause of the disease in all patients. Acute onset with hectic fever, shivering, profuse sweating, intoxication and development of multi-organ failure were the main clinical features of the disease. Embolism of the peripheral branches of pulmonary artery by septic embolus or micro thrombi were common symptoms. Ultrasound investigation played an important role in diagnosis of TVIE. It was the only criteria for the verification of the diagnosis in patients with fever of unknown origin until the appearance of valve damages and cardiac murmurs. All 35 (100%) patients underwent tricuspid valve replacement (TVR). 3 (8.57%) patients underwent redo TVR because of prosthetic valve endocarditis due to persistent intravenous drug abuse after surgery. The hospital mortality rate was 0%. Acute debut of the disease may be the first clinical feature of tricuspid valve infec­tive endocarditis in drug abusers. Ultrasound investigation is important for early diagnosis and effective treatment. Surgical treatment is indicated in cases of ineffective antibiotic therapy and massive tricuspid valve damages. Tricuspid valve replacement by a biological prosthesis was the treatment of choice in these patients. The use of biological prosthetic valve had good clinical re­sults with low thrombogenic risk and high resistance to infection. Nepalese Heart Journal | Volume 7 | No.1 | November 2010 (special issue) | Page 29-34 DOI: http://dx.doi.org/10.3126/njh.v7i1.8499

Middle cerebral and anterior choroidal artery watershed infarction

A 73-year-old patient (with arterial hypertension, aortic biological prosthetic valve, and atrial fibrillation as cardiovascular risk factors) presented with acute left-sided hemiplegia, hemianesthesia, and homonymous hemianopsia. Brain magnetic resonance imaging (MRI) revealed restricted diffusion (Fig. 1) in two areas corresponding to the watershed territories between the middle cerebral (MCA) and the anterior choroidal artery (AChA) territory, i.e. in the anterior part of the temporal lobe (Fig. 1a) between the medial and the lateral area (vascularised by AChA and MCA, respectively) and between the pars medialis and the pars lateralis (Fig. 1b) of the pallidum (vascularised by AChA and MCA, respectively) [1, 2]. Magnetic resonance angiography (MRA) showed carotid T-occlusion (Fig. 1e). Intravenous thrombolysis was given, followed by endovascular mechanical thrombectomy resulting in complete recanalisation and clinical recovery. Four days later, MRI showed stable diffusion-weighted imaging (DWI) abnormalities, now also seen on fluid attenuated inversion recovery (FLAIR) sequence (Fig. 1c, d). Hypoperfusion in the proper MCA and/or AChA territories was probably less profound (explaining clinical recovery after treatment and absence of MRI abnormalities) than in their watershed area (leaving FLAIR abnormalities).

104: Comparison of multidetector row computed tomography to echocardiography for evaluation of patients with mechanical and biological prosthetic valves

Our objective was to evaluate whether ECG gated multidetector-row computed tomographic (MDCT) imaging could detect the abnormalities of prosthetic heart valves. We reviewed the image sequences of 35 patients who underwent a MDCT and a echocardiography (TTE) with a total of 46 prosthetic valves (PV) in different position: 27 bileaflet PV, 2 tilting disc, 2 caged ball PV, and 15 biological PV. According to TTE data, 21 were abnormal and 25 normal. MDCT data were retrospectively reconstructed and analyzed using reformatting in anatomically adapted planes. The abnormalities on CT were following: 12 obstructions, 14 dehiscences and 1 vegetation. MDCT identified obstruction with a sensitivity of 100% and specificity of 84%. The causes for obstruction were subprosthetic tissue (pannus) (n=3), thrombus (n=2), leaflets calcifications (n=4), periprostetic and annulus calcifications (n=6). A good correlation was found between the mean prosthetic gradient on TTE and difference of angles for bileaflet PV on MDCT (r=0,7, p=0,0005). 4 patients with PV obstruction were re-operated and the MDCT imaging was confirmed by surgery. MDCT identified dehiscence of PV with a sensitivity of 100% and specificity of 84%. MDCT detect the false aneurysms (n=4) and sequels of ancient abscess (n=6). 5 patients were re-operated and the MDCT imaging of dehiscence was confirmed by surgery. In 6 cases, MDCT showed abnormalities that were not seen during TTE: 3 dehiscences of PV and 3 opening dysfunction of PV without significant obstruction (1 pannus, 1 calcification of prosthetic annulus and 1 asymmetry of opening. The Bjork PV cannot be exanimated on MDCT because of numerous artifacts. This experience demonstrates that MDCT have additional value because it can show perivalvular structures as well as cardiac and mediastinal abnormalities and can identify causes of PV dysfunction that constitute indications for surgery, but could be are missed at TTE.

A new approach to the interventional therapy of tricuspid regurgitation

Currently, there are no fully developed interventional approaches for the treatment of tricuspid regurgitation (TR). The aim of this study was to evaluate the feasibility of orthotopic interventional placement of a biological prosthetic valve in the tricuspid position by inserting, with a transvenous approach, a self-expandable valve-bearing stent into the right atrium. Based on findings of computerized tomography (CT), a model of the porcine right heart was obtained. A self-expanding vascular endoprosthesis, carrying a prosthetic heart valve, was reshaped to fit the superior vena cava and the tricuspid annulus. Fenestrations were created to allow blood flow from the inferior vena cava and coronary sinus. This new device ("tricuspid endoprosthesis": TE) was implanted operatively into the superior vena cava, right atrium, and tricuspid annulus in six pigs. CT demonstrated proper fitting of the device, and echocardiography demonstrated correct positioning and function of the TE. Five animals were successfully weaned from cardiopulmonary bypass. Autopsy confirmed correct positioning of the TE without major trauma to surrounding tissues. These findings demonstrate a complete interventional approach for treating TR.

Percutaneous Closure of an Aorto-Atrial Fistula After Surgery for Infective Endocarditis

A 44-year-old man was referred to the cardiology outpatient clinic due to dyspnea on exertion. He had undergone aortic valve replacement with a biological prosthetic valve (Carpentier-Edwards 23 mm, Edwards Lifesciences, Irvine, California) and reconstruction of the mitroaortic junction due to

Midterm Evaluation of Biological Prosthetic Valves in the Pulmonary Position of Grown-Up Patients

To examine the midterm clinical outcome of pulmonary valve replacement (PVR) with prosthetic valves. We reviewed 37 consecutive patients who underwent PVR with biological prosthetic valves between September 1999 and June 2010. The median age was 22.6 years (range: 6 to 70 years; three children). The primary diagnosis was Tetralogy of Fallot in 20 patients (54%). Valve pathology was regurgitation in 27 patients (72.9%). Cardiac surgery had been previously performed in 35 patients (94.5%). The median size of the prosthesis was 25 mm (range: 21 to 31 mm). The median follow-up was 42 months (range: 1.2 to 129 months). There were no early valve-related deaths. Hospital mortality was 2.7% (n = 1) and no patient required early rereplacement of prosthesis. Two patients required permanent pacemaker insertion. During follow-up, there was no late death, reoperation for structural valve degeneration, or valve thrombosis. Only one patient required repeated operation for endocarditis at 37 months follow-up. The actuarial survival at 5 years was 95.1 ± 3.8%. Overall freedom from reoperation after PVR at 5 years was 93.0 ± 8.6%. At last follow-up, 34 patients (91.8%) were NYHA class I versus 20 patients (54%) preoperatively (p < 0.05). In the 35 surviving patients who did not undergo redo-PVR, there was no-mild regurgitation and the peak PV gradient was 20.4 ± 10.2 mm Hg (16.2 ± 9.3 mm Hg preoperatively). Thirty-two patients (91.4%) had good right ventricular function compared with 26 patients (74.2%) preoperatively. PVR with biological prosthetic valves can be performed with good midterm survival, functional status, and haemodynamics.

Chronic Q Fever with No Elevation of Inflammatory Markers: A Case Report

We describe the case of a 55-year-old man with a biological prosthetic aortic valve who suffered from epigastrium and right hypochondrium pain associated with intermittent night sweats. Liver biopsy showed infectious hepatitis pattern without pathognomonic features. Coxiella burnetii serology was suggestive of chronic Q fever, and modified Duke's criteria for endocarditis were also fulfilled. The authors present a brief literature review concerning chronic Q fever, emphasizing absent previous reports of chronic Q fever with hepatitis and endocarditis and no increase in inflammatory markers.

A vanishing left ventricular thrombus: Live imaging by trans-thoracic 2D-echocardiography

A 81-year-old was admitted to our intensive care unit because of syncope and recent onset palpitations . His clinical history included chronic heart failure with severe left ventricular dysfunction and previous mitral and aortic valves replacement by biological prosthetic valves, previous pace-maker implantation and chronic atrial fibrillation requiring oral anticoagulant therapy. At admission, the patient was conscious, eupnoic, without signs of peripheral ipoperfusion , although blood pressure was 80/60mmHg.