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Valve Function (valve + function)

Distribution by Scientific Domains
Medical Sciences100%

Kinds of Valve Function

  • prosthetic valve function
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    Selected Abstracts

    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]

    Prosthetic Valve Dysfunction Presenting as Intermittent Acute Aortic Regurgitation

    ECHOCARDIOGRAPHY, Issue 8 2008
    Dali Fan M.D., Ph.D.
    We describe the case of a 43 year old man with a history of aortic stenosis, for which he had undergone aortic valve replacement in 1991 with a 25-mm Medtronic Hall prosthesis. He presented with several acute episodes of dyspnea and flash pulmonary edema. Transthoracic and transesophageal echocardiography performed to evaluate prosthetic valve function revealed evidence of "intermittent" episodes of AI, documented on color M-mode flow mapping to have a variable duration of diastolic flow (early vs. pandiastolic) across the left ventricular outflow tract and the pulse wave Doppler in the descending thoracic aorta showed similar variability in the duration of diastolic flow reversal. [source]

    An echocardiographic and auscultation study of right heart responses to training in young National Hunt Thoroughbred horses

    EQUINE VETERINARY JOURNAL, Issue S36 2006
    G. LIGHTFOOT
    Summary Reasons for performing study: There are few data available to determine the effect of training on cardiac valve function. Objectives: To investigate the effect of commercial race training on right ventricular (RV) and tricuspid valve function in an untrained group of National Hunt Thoroughbreds (TB). Material and methods: Cardiac auscultation, guided M-mode echocardiography of the RV, and colour flow Doppler (CFD) tricuspid valve and right atrium were performed in 90 TB horses (age 2,7 years) 1998,2003. Forty horses were examined at least once and 48 horses were examined on at least 2 occasions. Examinations were then classified as: i) before commencement of race training, ii) after cantering exercise had been sustained for a period of 8,12 weeks and iii) at full race fitness. Tricuspid valve regurgitation (TR) murmurs were graded on a 1,6 scale and CFD echocardiography TR signals were graded on a 1,9 scale. Right ventricular internal diameter (RVID) in diastole and systole (RVIDd and RVIDs) was measured by guided M-mode. Associations between continuous RVID and TR measures and explanatory covariates of weight, age, heart rate, yard and stage of training were examined using general linear mixed models with horse-level random effects. Results: On average, RVIDd and RVIDs increased by 0.08 and 0.1 cm, respectively, per year increase in age (P=0.1 and 0.02) and by 0.3 and 0.4 cm, respectively between pre-training and race fitness (P = 0.07 and 0.005). Tricuspid regurgitation score by colour flow Doppler increased by 0.6/year with age (P<0.0001) and by 1.8 between pre-training and race fitness (P< 0.0001). No significant associations were found between any outcomes and weight, heart rate and training yard. Due to the high level of co-linearity between age and training, multivariable models including both terms were not interpretable. Conclusions and clinical relevance: Athletic training of horses exerts independent effects on both severity and prevalence of tricuspid valve incompetence. This effect should therefore be taken into account when examinations are performed. Dimensions of RV increase with age and training in TB horses in a manner that appears to be similar to that of the LV. [source]

    Pacemaker Lead Prolapse through the Pulmonary Valve in Children

    PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2007
    CHARLES I. BERUL M.D.
    Background:Transvenous pacemaker leads in children are often placed with redundant lead length to allow for anticipated patient growth. This excess lead may rarely prolapse into the pulmonary artery and potentially interfere with valve function. We sought to determine the response to lead repositioning on pulmonary valve insufficiency. Methods:Retrospective reviews of demographics, lead type, implant duration, and radiography and echocardiography. Results:A total of 11 pediatric patients were identified with lead prolapse through the pulmonary valve, of which nine patients underwent procedures to retract and reposition the lead (age at implant 9 ± 4 years, age at revision 13 ± 4 years). The implant duration prior to revision was 4 ± 3 years. Two leads required radiofrequency extraction sheaths for removal, two pulled back using a snare, while five leads were simply retracted and repositioned. Tricuspid regurgitation was none/trivial (three), mild (four), or moderate (two) and only two improved with repositioning or replacement. Pulmonary regurgitation preoperatively was mild (three), mild-moderate (two), or moderate (four) compared with trivial (three), mild (four), and moderate (two) after revision. Patients with longer-term implanted leads had less improvement in pulmonary insufficiency. Two patients had mild pulmonary stenosis from lead-related obstruction. Conclusions:Prolapse of transvenous pacing leads into the pulmonary artery can occur when excess slack is left for growth. Leads can often be repositioned, but may require extraction and replacement, particularly if chronically implanted and adherent to valve apparatus. Lead revision does not always resolve pulmonary insufficiency, potentially leaving permanent valve damage. [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]

    A prospective retrieval study to determine how speaking valve failure is effected by colonization

    CLINICAL OTOLARYNGOLOGY, Issue 6 2000
    S.R. Ell
    Introduction. It has been suggested that Groningen Low Resistance (GLR) valve failure is associated with biofouling of the valve's oesophageal surface and hinge areas. However, the valve edges are responsible for efficient valve function. 1 Therefore, valve edge colonization should be the most important factor determining valve failure. The null hypothesis that valve edge colonization was not associated with failure was tested using 106 GLR valves retrieved, after failure, from 41 patients. Methods. The opening pressures, reverse opening pressures and forward resistances of the new valves were determined using apparatus validated previously. 2 The pressure/flow parameters were measured again after removal and the changes calculated. The degree of colonization of each valve edge, oesophageal surface, hinge area, tracheal surface and valve lumen was scored using 100-mm linear analogue scales. The changes, in pressure/flow parameters were examined for associated with colonization of the five areas described above. Results. The increase in the opening pressure and resistance, and decrease in reverse opening pressure, of the retrieved valves was significant compred with new valves. The increase in opening pressure was associated with colonization of the valve edge (rs = 0.262, P = 0.007). The decrease in reverse opening pressure was associated with colonization of the valve edge, hinge areas and oesophageal surface (rs = 0.266, P = 0.006; rs = 0.271, P = 0.005; rs = 0.271, P = 0.004, respectively). The increase in resistance was associated with colonization in all areas (rs , 0.367, P = 0.0005). Conclusion. This study demonstrated that colonization of the valve edge is associated significantly with the changes, in pressure/flow parameters of failed valves. [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]