Search results for "Heart Valves"

Long-term storage in liquid nitrogen does not affect cell viability in cardiac valve allografts

2007

Liquid nitrogen is the most common medium used by tissue banks for the storage of cryopreserved heart valves. This study evaluates the effect of the length of storage on human cryopreserved heart valves. Human tissues (14 aortic and 13 pulmonary) were frozen in a controlled-rate freezer (1 degrees C/min) and stored in the liquid phase of a nitrogen tank for 9.1+/-1.6 years. The preservative solution was medium M199 containing 5% human serum albumin and 10% Me(2)SO. After thawing in a water bath at 42 degrees C, the cryoprotectant was removed. Then, fragments from vascular wall and leaflet were dissected. Explant cultures and histological studies were performed in order to assess cell viabil…

Incidence of thromboembolic complications in patients with mechanical heart valves with a subtherapeutic international normalized ratio.

2008

Objective Subtherapeutic international normalized ratios are frequently encountered in clinical practice, and patients with mechanical heart valves with inadequate anticoagulation may be exposed to an increased risk of thromboembolic events. There are no data on thromboembolic event risk for these patients. Methods We assessed the current practice patterns in the management of patients with mechanical heart valves with subtherapeutic international normalized ratios and assessed the risk of thromboembolic complications in this setting. The charts of patients with mechanical heart valves followed up in two anticoagulation clinics were reviewed. Patients with a history of stable, therapeutic a…

Clinical and morphological characteristics in Streptococcus bovis endocarditis: a comparison with other causative microorganisms in 177 cases

1999

Aim—To compare the clinical and morphological characteristics of patients with Streptococcus bovis endocarditis with those of patients with endocarditis caused by other microorganisms. Methods—177 consecutive patients (Streptococcus bovis, 22; other streptococci, 94; staphylococci, 44; other, 17) with definite infective endocarditis according to the Duke criteria were included. All patients underwent transthoracic and transoesophageal echocardiography. In 88 patients, findings from surgery/necropsy were obtained. Results—S bovis endocarditis was associated with older patients, with a higher mortality (p = 0.04), and with a higher rate of cardiac surgery (p < 0.001) than other microorganisms…

The presence of infection-related antiphospholipid antibodies in infective endocarditis determines a major risk factor for embolic events.

1999

Abstract OBJECTIVES The impact of infection-associated antiphospholipid antibodies (APA) on endothelial cell activation, blood coagulation and fibrinolysis was evaluated in patients with infective endocarditis with and without major embolic events. BACKGROUND An embolic event is a common and severe complication of infective endocarditis. Despite the fact that APAs are known to be associated with infectious diseases, their pathogenic role in infective endocarditis has not been clearly defined. METHODS The relationship among the occurrence of major embolic events, echocardiographic vegetation size, endothelial cell activation, thrombin generation, fibrinolysis and APA was examined in 91 patie…

Assessment of successful valve reconstruction by intraoperative transesophageal echocardiography (TEE)

1986

In 17 patients (10 patients with mitral insufficiency, 5 patients with tricuspid regurgitation, 2 patients with mitral stenosis) the result of valve reconstruction was evaluated by intraoperative two-dimensional transesophageal contrast-echocardiography (TEE). Therefore, 1–2 cc of an agitated contrast-medium (GelifundolR) were injected into the left or right ventricle. The result of reconstruction was assessed by the extent of regurgitant microbubbles into the left or right atrium. A successful valve repair could be demonstrated in 15 patients without or with only minimal regurgitation of contrast-fluid. In one patient residual severe mitral insufficiency after valve reconstruction could on…

Heart Valve Abnormalities in Systemic Sclerosis Patients; A Multicenter Cohort Study and Review of the Literature

2020

Background Systemic sclerosis (SSc) is a chronic autoimmune disease that is characterized by vasculopathy and fibrosis of the skin and visceral organs. Heart valve diseases are poorly described and generally not considered typical of SSc. We aimed to describe valvular abnormalities in a multicenter cohort of SSc patients and to investigate their correlation with SSc features. Methods We recruited 118 consecutive SSc patients (male/female, 14/104; mean age, 55.2 ± 12.1 years) in 3 rheumatology centers in Sicily, Italy, from January to October 2019. Results Mitral and tricuspid valve insufficiency was found in 85% and 91% of patients, respectively; regurgitations were generally mild and never…

Heart valve tissue engineering: how far is the bedside from the bench?

2015

Heart disease, including valve pathologies, is the leading cause of death worldwide. Despite the progress made thanks to improving transplantation techniques, a perfect valve substitute has not yet been developed: once a diseased valve is replaced with current technologies, the newly implanted valve still needs to be changed some time in the future. This situation is particularly dramatic in the case of children and young adults, because of the necessity of valve growth during the patient's life. Our review focuses on the current status of heart valve (HV) therapy and the challenges that must be solved in the development of new approaches based on tissue engineering. Scientists and physicia…

Effect of Physiologic Oscillatory Fluid Shear Stress on Engineered Heart Valve Tissue Formation.

2010

It was previously demonstrated that combined flexure and flow in vitro conditioning augments engineered heart valve tissue formation using bone marrow-derived mesenchymal stem cells (MSC) seeded on polyglycolic acid (PGA)/poly-L-lactic acid (PLLA) blend nonwoven fibrous scaffolds (Engelmayr, et al., Biomaterials 2006; vol. 27 pp. 6083-95). Additionally, seeded scaffolds incorporated into a tissue engineered valve construct experienced significant increases in tissue formation rates with media supplementation (basic fibroblast growth factor [bFGF] and ascorbic acid-2-phosphate [AA2P]) and dynamic conditioning approximating pulmonary valve levels (Ramaswamy, et al., Biomaterials 2010; vol. 31…

Effects of Rastering Velocity on Electrospun Polyeurthane Structure and Mechanical Properties

2010

Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering

2014

Native semi-lunar heart valves are composed of a dense fibrous network that generally follows a curvilinear path along the width of the leaflet. Recent models of engineered valve leaflets have predicted that such curvilinear fiber orientations would homogenize the strain field and reduce stress concentrations at the commissure. In the present work, a method was developed to reproduce this curvilinear fiber alignment in electrospun scaffolds by varying the geometry of the collecting mandrel. Elastomeric poly(ester urethane)urea was electrospun onto rotating conical mandrels of varying angles to produce fibrous scaffolds where the angle of fiber alignment varied linearly over scaffold length.…