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Valve Annulus (valve + annulus)
Selected AbstractsRole of Echocardiography in Assessing the Mechanism and Effect of Ramipril on Functional Mitral Regurgitation in Dilated CardiomyopathyECHOCARDIOGRAPHY, Issue 4 2005D.M. (Card), F.I.A.E., F.I.A.M.S., F.I.C.C., F.I.C.P., I.B. Vijayalakshmi M.D. The objectives of this article are to determine the possible mechanism of functional mitral regurgitation in patients with dilated cardiomyopathy (DCM) and to know the effect of ramipril on left ventricle (LV) and mitral regurgitation by ECHO. Several postulates are put forth for functional mitral regurgitation in DCM, and mitral annular dilatation is said to be the primary mechanism in the past, but the exact mechanism is not clear. Though angiotensin converting enzyme (ACE) inhibitors are known to remodel the LV, their beneficial effect in patients with DCM with functional mitral regurgitation is not known. Various cardiac dimensions and degree of mitral regurgitation were measured by echocardiography in 30 normal control group and in 30 patients with DCM of various etiologies except ischemic, before and after ramipril therapy. There was a significant difference in all parameters especially sphericity of left ventricle and position of papillary muscles (P < 0.0003) in DCM patients, but mitral valve annulus did not show significant change (P < 0.3) compared to control group. In 50% of the patients, the functional mitral regurgitation totally disappeared. In 30% of patients, it came down from grade II to I or became trivial. In 20% of patients, it remained unchanged. There was remarkable improvement in sphericity, LV dimension, volumes, and EF%, which increased from 31 ± 9.81 to 39.3 ± 8.3% (P < 0.0003). It is concluded that echocardiography clearly demonstrates the increased sphericity of LV in DCM. The lateral migration of papillary muscles possibly plays a major role in functional mitral regurgitation. Ramipril significantly reduces not only sphericity but also functional mitral regurgitation. [source] Percutaneous Treatment for Mitral Regurgitation: The QuantumCor SystemJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2008RICHARD R. HEUSER M.D. Aims:Percutaneous edge-to-edge techniques and annuloplasty have been used to treat mitral regurgitation (MR). However, neither intervention can be performed reliably a second time and, with annuloplasty, a foreign body is left behind. The mitral and tricuspid annuli are areas of dense collagen (Fig. 1); treatment with radiofrequency (RF) energy in sheep reduces their size, and can be repeated without affecting the coronary sinus. RF energy may also be used in leaflet procedures. Our aim was to improve mitral valve competence using techniques that can be incorporated into a minimally invasive approach. Figure 1. This trichrome stain slide shows the amount of collagen present in the mitral annulus (in green). Methods:In open-heart procedures in 16 healthy sheep (6 with naturally occurring MR), we used a malleable probe (QuantumCor, Inc., Lake Forest, CA) that conforms to the annular shape to deliver RF energy via a standard generator to replicate a surgical mitral annular ring. Four segments of the posterior mitral valve annulus were treated while on cardiopulmonary support via a left thoracotomy with access via the atrial appendage. Seven sheep were followed chronically. Results:All sheep underwent intracardiac echocardiography (ICE) or direct circumferential measurement of the mitral annulus before and after RF therapy. RF therapy was administered in less than 4 minutes in each case, and the mean anteroposterior (AP) annular distance was reduced by a mean of 5.75 ± 0.86 mm (23.8% reduction, P< 0.001). In the 6 sheep with nonischemic MR, regurgitation was eliminated. Acute histopathology (HP) demonstrated no damage to the leaflets, coronary sinuses, or coronary arteries. At 30 days, the AP distance continued to be reduced in the 7 surviving sheep (mean 5.0 ± .6 mm, 21.4% reduction, P< 0.001). Conclusions:In a sheep model, RF energy applied for less than 4 minutes per case at subablative temperatures in four quadrants of the posterior mitral valve annulus reduced the AP and circumferential annular distances significantly, and eliminated nonischemic MR. Results will need to be confirmed in follow-up studies to determine safety and efficacy. RF energy administered as a novel, percutaneous method of mitral valve annuloplasty may have the potential to reduce morbidity and mortality associated with current surgical techniques. [source] Aortic and mitral regurgitation: Quantification using moving slice velocity mappingJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2001Sebastian Kozerke PhD Abstract Comprehensive assessment of the severity of valvular insufficiency includes quantification of regurgitant volumes. Previous methods lack reliable slice positioning with respect to the valve and are prone to velocity offsets due to through-plane motion of the valvular plane of the heart. Recently, the moving slice velocity mapping technique was proposed. In this study, the technique was applied for quantification of mitral and aortic regurgitation. Time-efficient navigator-based respiratory artifact suppression was achieved by implementing a prospective k-space reordering scheme in conjunction with slice position correction. Twelve patients with aortic insufficiency and three patients with mitral insufficiency were studied. Aortic regurgitant volumes were calculated from diastolic velocities mapped with a moving slice 5 mm distal to the aortic valve annulus. Mitral regurgitant flow was indirectly assessed by measuring mitral inflow at the level of the mitral annulus and net aortic outflow. Regurgitant fractions, derived from velocity data corrected for through-plane motion, were compared to data without correction for through-plane motion. In patients with mild and moderate aortic regurgitation, regurgitant fractions differed by 60% and 15%, on average, when comparing corrected and uncorrected data, respectively. Differences in severe aortic regurgitation were less (7%). Due to the large orifice area of the mitral valve, differences were still substantial in moderate-to-severe mitral regurgitation (19%). The moving slice velocity mapping technique was successfully applied in patients with aortic and mitral regurgitation. The importance of correction for valvular through-plane motion is demonstrated. J. Magn. Reson. Imaging 2001;14:106,112. © 2001 Wiley-Liss, Inc. [source] Percutaneous stent-mounted valve for treatment of aortic or pulmonary valve diseaseCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2004John 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] | ||||||||||