			Home About us Contact

Prosthetic Valves (prosthetic + valve)

Distribution by Scientific Domains

Medical Sciences	100%

Terms modified by Prosthetic Valves

prosthetic valve function

Selected Abstracts

A Technique of Snaring Method for Fitting a Prosthetic Valve into the Annulus

JOURNAL OF CARDIAC SURGERY, Issue 1 2005
Shigeo Nagasaka M.D.
We modified the previously reported method and designed a simpler tying technique. Patients: We performed 11 aortic (AVR: including four cases for calcified aortic stenosis (AS) with a small annulus and one cases for infective endocarditis with intramuscular abscess cavity), eight mitral valve replacements (MVR), and one tricuspid valve replacement (TVR: for corrected transposition of the great arteries). Techniques and Results: A PV was implanted using 2-0 polyester mattress sutures with a pledget. Each of the two tourniquets held a suture at the bottom of the annulus and at the opposite position to fit a PV. The sutures between each snare were tied down from the bottom to the top. In MVR, after seating of a PV with two tourniquets, we could make sure that no native tissue of any preserved mitral apparatus disturbed PV leaflet motion. In calcific AS, a PV had a good fitting into the annulus because of tourniquets applied to unseated part during tying sutures. In AVR for infective endocarditis, mattress sutures supported by a Teflon pledget were placed to close the abscess cavity. After snaring on one of these sutures, we tied down the sutures, ensuring that they did not cut through the friable tissues. In TVR, we found that native leaflets interfered with PV motion after seating down the prosthesis and those leaflets were resected before tying down the sutures. Postoperative transesophageal echocardiography showed no paravalvular leakage in any patients and excellent PV functions. [source]

Guidelines for the Evaluation of Prosthetic Valves with Echocardiography and Doppler Ultrasound: Value and Limitations

ECHOCARDIOGRAPHY, Issue 1 2010
Fadi G. Hage M.D.
No abstract is available for this article. [source]

I PREVENT Bacterial Resistance.

DERMATOLOGIC SURGERY, Issue 10 2009
An Update on the Use of Antibiotics in Dermatologic Surgery
BACKGROUND AND OBJECTIVES Prophylaxis may be given to prevent a surgical wound infection, infective endocarditis (IE), or infection of a prosthetic joint, but its use before cutaneous surgery is controversial. Our aim was to review the current literature and provide a mnemonic to assist providers in appropriately prescribing prophylactic antibiotics. METHODS AND MATERIALS We reviewed the current literature, including the new guidelines provided by the American Heart Association (AHA). RESULTS The new AHA guidelines recommend prophylaxis for patients with high risk of an adverse outcome from IE instead of high risk of developing IE. The American Academy of Orthopedic Surgeons and the American Dental Association also provide guidelines. Given the paucity of conclusive studies, prophylaxis against a surgical wound infection is based more on clinical judgment. CONCLUSION The mnemonic we propose, "I PREVENT," represents: Immunosuppressed patients; patients with a Prosthetic valve; some patients with a joint Replacement; a history of infective Endocarditis; a Valvulopathy in cardiac transplant recipients; Endocrine disorders such as uncontrolled diabetes mellitus; Neonatal disorders including unrepaired cyanotic heart disorders (CHDs), repaired CHD with prosthetic material, or repaired CHD with residual defects; and the Tetrad of antibiotics: amoxicillin, cephalexin, clindamycin, and ciprofloxacin. [source]

EFFECT OF PARAPROSTHETIC MODERETE TO SEVERE MITRAL REGURGITATION ON EMBOLIC EVENTS IN PATIENTS WITH PROSTHETIC MITRAL VALVES

ECHOCARDIOGRAPHY, Issue 5 2004
C. Cevik
Thromboembolism is the major chronic risk for patients with mechanical prosthetic heart valves. Although optimal oral anticoagulantion is the key determinant for embolic events (EE) in these patients; other factors also contribute to this complication. We studied the prevalence and determinants of embolic events in patients with mitral prosthetic heart valves undergoing transesophageal echocardiography (TEE). 210 patients (86 male and 124 female, mean age 45.1 +/, 9.6 years) underwent a TEE study for evaluation of prosthetic valve functions. Clinical and TEE findings of the patients were as follows: Atrial fibrillation in 132 (%62) patients, prosthetic valve thrombus in 55 (%26) suboptimal INR (INR < 1.8) in 61 (%29) pts, left atrial spontenous echocardiographic contrast (SEC) in 31 (%14) patients, paraprosthetic moderete-severe mitral regurgitation (MR) in 28 (%13), left atrial (LA) and/or left atrial appendix (LAA) thrombus in 41 (%19), LA and/or LAA outflow velocities <0.25 m/sn in 21 patiens (%10), left atrial diameter >6 cm in 47 (%22). 72 patients had a history of EE in the previous 6 months (%34). In no patients were there any EE in the presence of paraprosthetic moderate to severe MR. Both with univariate and multivariate analysis presence of prosthetic valve and LA and/or LAA thrombus, absence of paraprosthetic moderete-severe MR, suboptimal INR, atrial fibrillation were found to be independent predictors for embolic events. Conclusions: Although the presence of prosthetic valve and LA and/or LAA thrombus, suboptimal INR, and AF predict EE, clinical and echocardiographic data support the protective effect of paraprosthetic moderate to severe MR against EE in pts with mitral prosthetic valves. [source]

Treatment for Mechanical Valve Thrombosis in the Right Heart: Combined Pharmacological and Mechanical Thrombolysis

ARTIFICIAL ORGANS, Issue 8 2010
Shigeaki Aoyagi
Abstract We report clinical results of combined pharmacological and mechanical thrombolysis for mechanical prosthetic valve thrombosis (PVT) in the right heart. Between January 1992 and December 2008, combined thrombolysis, which consisted of an intravenous infusion of urokinase together with mechanical disruption of thrombus in a prosthetic valve by temporarily increasing the cardiac pacing rate, was performed in three patients with four cases of mechanical PVT in the right heart. The prosthetic valve in all three patients was a bileaflet mechanical valve, and was located in the tricuspid position in two patients and in the pulmonary position in the remaining patient. PVT was diagnosed by echocardiography and cineradiography. Thrombolysis was successful in all four cases in the three patients, and no hemorrhagic complications or clinically symptomatic pulmonary embolisms were observed. Mechanical disruption of thrombus using a pacemaker appears to be an effective adjunctive modality to thrombolysis with fibrinolytic agents for PVT in the right heart. Combined pharmacological and mechanical thrombolysis may improve success rates and reduce the time required for thrombolysis of PVT. [source]

Usefulness of Live/Real Time Three-Dimensional Transthoracic Echocardiography in Evaluation of Prosthetic Valve Function

ECHOCARDIOGRAPHY, Issue 10 2009
Preeti Singh M.D.
We studied 31 patients with prosthetic valves (PVs) using two-dimensional and three-dimensional transthorathic echocardiography (2DTTE and 3DTTE, respectively) in order to determine whether 3DTTE provides an incremental value on top of 2DTTE in the evaluation of these patients. With 3DTTE both leaflets of the St. Jude mechanical PV can be visualized simultaneously, thereby increasing the diagnostic confidence in excluding valvular abnormalities and overcoming the well-known limitations of 2DTTE in the examination of PVs, which heavily relies on Doppler. Three-dimensional transthorathic echocardiography provides a more comprehensive evaluation of PV regurgitation than 2DTTE with its ability to more precisely quantify PV regurgitation, in determining the mechanism causing regurgitation, and in localizing the regurgitant defect. Furthermore, 3DTTE is superior in identifying, quantifying, and localizing PV thrombi and vegetations, in addition to the unique feature of providing a look inside mass lesions by serial sectioning. These preliminary results suggest the superiority of 3DTTE over 2DTTE in the evaluation of PVs and that it provides incremental knowledge to the echocardiographer. [source]

ORIGINAL INVESTIGATIONS: Tissue Harmonic Imaging in Echocardiography: Better Valve Imaging, But at What Cost?

ECHOCARDIOGRAPHY, Issue 2 2008
Karin Hawkins M.D.
Background: Tissue harmonic imaging (THI) improves echocardiographic image quality and is widely utilized. Unfortunately it also makes structures appear artificially thickened. We sought to examine its impact on the imaging of left-sided heart valves. Methods: A large echocardiographic database was searched for full, standard transthoracic echocardiographic exams performed 12-month periods before (n = 3,786) and after (n = 3,914) transition to THI at a single institution. Patients with prosthetic valves were excluded. Results: The mean age of patients was 63 ± 17 years and 65% were men. No appreciable difference in demographics was observed between time periods. While inadequate visualization of the mitral valve was reduced by 30% using THI (P = 0.014), reports of leaflet thickening increased by 28% (P = 0.005). Similarly, inadequate aortic valve visualization was reduced by 53% with THI (P < 0.001), at the expense of more aortic sclerosis (+6%, P = 0.034). Among the 480 patients with echocardiograms using each modality (time interval between studies: 370 ± 143 days), THI did not appreciably improve visualization of the either valve. Although no significant increase in mitral thickness was seen with THI, aortic sclerosis was increased by at least one grade in 24.5% (P < 0.006). Conclusion: This study suggests that while THI enhances imaging of difficult to visualize valves, it may overestimate mitral and aortic valve thickness. This could lead to overdiagnosis and unnecessary follow-up studies. Cardiologists interpreting THI echocardiograms should become familiar with the modality's shortcomings. [source]

EFFECT OF PARAPROSTHETIC MODERETE TO SEVERE MITRAL REGURGITATION ON EMBOLIC EVENTS IN PATIENTS WITH PROSTHETIC MITRAL VALVES

Abciximab Treatment for Obstructive Prosthetic Aortic and Mitral Valve Thrombosis in the Presence of Large Thrombi, Cardiogenic Shock, and Acute Evolving Embolic Stroke

ECHOCARDIOGRAPHY, Issue 1 2004
Atiar M Rahman M.D., Ph.D.
Obstructive thrombosis of left-sided mechanical prosthetic valves is a life-threatening complication. Intravenous thrombolytic therapy is contraindicated due to risk of clot embolization and surgical treatment is often required for hemodynamically unstable patients. We report for the first time the successful use of abciximab in the management of a patient in cardiogenic shock with multiple prosthetic valve obstructive thrombosis and evolving embolic stroke. Serial Doppler echocardiography and cinefluoroscopy demonstrated resolution of thrombi, improvements in transvalvular gradients and improvement in leaflet motion. This observation suggests abciximab should be considered as a therapeutic option in the treatment of obstructed prosthetic heart valves. (ECHOCARDIOGRAPHY, Volume 21, January 2004) [source]

Cavitation versus Degassing: In Vitro Study of the Microbubble Phenomenon Observed During Echocardiography in Patients with Mechanical Prosthetic Cardiac Valves

ECHOCARDIOGRAPHY, Issue 7 2002
Grégoire Girod M.D.
Background: With the advent of second harmonic imaging in echocardiography, microbubbles have been observed during opening and closure of mechanical prosthetic valves. The single phenomenon of cavitation, an extremely short event described in the literature, cannot explain the persistence of microbubbles during several hundred milliseconds. Therefore, in vitro we reproduced two distinct phenomena created by a local depression occurring during the closure and/or opening of prosthetic valves: Cavitation and degassing. Methods: We used a water circuit system enriched with CO2 that passes through a Venturi tube in order to create variable pressure gradients. Three types of observations were performed: (1) the dimensions of the bubbles as a function of pressure, (2) calibration of the echocardiograph, and (3) comparison and illustrations of the difference between bubble formation by cavitation (vaporization) and degassing (liberation of CO2). Results: According to the different pressures exerted, the dimensions of the bubbles only vary by several microns, not measurable in practice. Second, the calibration of the echocardiograph reveals that the dimensions of the bubbles measured by ultrasound are greater by a factor of 1.75. Finally, the observed cavitation is a short phenomenon (several milliseconds) and happens under a great local pressure gradient. The degassing produces microbubbles lasting up to as long as > 1 second under much lower pressure. Conclusion: This in vitro study suggests that microbubbles observed during several hundred milliseconds after the opening of prosthetic cardiac valves are the result of degassing of CO2 in blood rather than a cavitation phenomenon as suggested in the literature. [source]

Percutaneous stent-mounted valve for treatment of aortic or pulmonary valve disease

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2004
John G. Webb MD
Abstract The objective of this study was to develop a prosthetic cardiac valve designed for percutaneous transcatheter implantation. Percutaneous catheter-based therapies play a limited role in the management of cardiac valve disease. Surgical implantation of prosthetic valves usually requires thoracotomy and cardiopulmonary bypass. The stent-valve is constructed of a rolled sheet of heat-treated nitinol. Although malleable when cooled, once released from a restraining sheath at body temperature the stent unrolls, becomes rigid, and assumes its predetermined cylindrical conformation. A ratcheting lock-out mechanism prevents recoil and external protrusions facilitate anchoring. Valve leaflets are constructed of bovine pericardium. The feasibility of catheter implantation, prosthetic valve function, and survival were investigated in an animal model. In vitro and pulse duplicator testing documented valve durability. Endovascular delivery of the prototype stent-valve to the aortic or pulmonary position was feasible. Accurate positioning was required to ensure exclusion of the native valve leaflets and, in the case of the aortic valve, to avoid compromise of the coronary ostia or mitral apparatus. Oversizing of the stent in relation to the valve annulus was desirable to facilitate anchoring and prevent paravalvular insufficiency. Stent-valve implantation proved feasible and compatible with survival in an animal model. Transcatheter implantation of prosthetic valves is possible. Further evolution of this technology will involve lower-profile devices with design features that facilitate vascular delivery, visualization, positioning, deployment, and valvular function. Catheter Cardiovasc Interv 2004;63:89,93. © 2004 Wiley-Liss, Inc. [source]

Infective endocarditis in Greece: a changing profile.

CLINICAL MICROBIOLOGY AND INFECTION, Issue 6 2004
Epidemiological, microbiological, therapeutic data
Abstract The epidemiology, and clinical and microbiological spectrum, of infective endocarditis (IE) in Greece was analysed in a prospective 4-year study in a tertiary hospital and a heart surgery centre in Athens. In total, 101 cases of IE (71 men, 30 women, aged 54.4 ± 17.1 years) were studied, with a follow-up period of 3 months. Seventy-seven cases were definite and 24 possible; 59 involved native valves (native valve endocarditis; NVE), 31 prosthetic valves (prosthetic valve endocarditis; PVE), of which nine were early and 22 late, and 11 permanent pacemakers (pacemaker endocarditis; PME). There was a predominant involvement of aortic (48/101) and mitral (40/101) valves. Seven patients had rheumatic valvular disease, two had mitral valve prolapse, and eight had a previous history of IE. Thirteen and six patients had undergone dental and endoscopic procedures, respectively. In 13 patients, intravenous catheters were used within the 3 months before diagnosis of IE. There were three intravenous drug users among the patients. Staphylococcus aureus was the most important pathogen, isolated in 22% of cases, followed by viridans streptococci (19%) and coagulase-negative staphylococci (16%). Enterococcus spp. were responsible for 3%, HACEK group for 2%, and fungi for 6% of cases. Viridans streptococci were the leading cause of NVE (29%), Staphylococcus epidermidis of PVE (16%), and S. aureus of PME (54.5%). Six of 22 S. aureus and ten of 16 S. epidermidis isolates were methicillin-resistant. Surgical intervention, including total pacemaker removal, was performed in 51.5% of patients. Overall mortality was 16%, but was 29% with PVE, and was significantly higher with medical than with combined surgical and medical therapy (24.5% vs. 8%). Compared with previous studies, there were changing trends in the epidemiology, microbiology, treatment and prognosis of IE in Greece. [source]