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PubMed1995

Isolated cleft mitral valve: valve reconstruction techniques.

Reports concerning an isolated cleft of the anterior mitral valve are rare. This congenital anomaly of the mitral valve is usually repaired by suturing the edges of the cleft. We report 4 cases of isolated anterior mitral cleft. The patients ranged in age from 13 to 41 years. The clinical symptoms were those typical of mitral insufficiency. In all 4 patients, preoperative echocardiography was able to establish the exact anatomic diagnosis. In 1 patient, the cleft was directly sutured, whereas, in the other 3 patients, a fibrous reaction of the edges of the cleft with a subsequent lack of valvular tissue made direct suture technically impossible. Instead, the fibrous edges of the cleft were resected and the anterior leaflet of the mitral valve was reconstructed using an autologous pericardial patch pretreated with buffered glutaraldehyde. All 4 patients underwent annuloplasty together with placement of a Carpentier mitral ring. Postoperative echocardiograms have confirmed good results of the repair; 1 patient has a trivial insufficiency and 3 have a completely competent mitral valve.

Adolescent↗

PubMed1983

Steady flow development past valve prostheses in a model human aorta. I. Centrally occluding valves.

In this paper, laser-Doppler anemometry measurement of steady flow development in a model human aorta has been reported. Studies were made with uniform entry flow at the root of the aorta and our measurements showed the establishment of a pair of Dean vortices in the mid-arch region. Subsequently, the nature of flow development past centrally occluding caged ball valves in the model aorta was investigated. Our studies showed that in the ascending aorta, an asymmetric velocity profile is obtained with larger velocity gradients towards the inner wall of tertiary curvature (anatomically the left lateral wall) with centrally occluding valves. The peripheral flow past these valves prevented the development of Dean vortices in the mid-arch region. The caged ball valves at the root of the aorta had no discernible effect on the velocity profiles in the brachio-cephalic artery.

Aorta↗

PubMed1985

Experimental study of physiological pulsatile flow past valve prostheses in a model of human aorta--I. Caged ball valves.

Pulsatile flow development past a caged ball valve in a model human aorta was studied using laser Doppler anemometry. Velocity profiles measured in the ascending aorta and in the mid-arch region were strongly influenced by the geometry of the valve at the root of the aorta. Velocity profiles distal to the valve were asymmetric with jet-like flow in the peripheral region having larger velocity magnitudes towards the left lateral wall. In early diastole, a streamwise vortex motion was observed throughout the model aorta with fluid moving towards the downstream direction along the left lateral wall and reversed flow along the right lateral wall. With the caged ball valve at the root of the aorta, no reversed flow was observed along the inner wall of curvature in the mid-arch region.

Aortic Valve↗

PubMed2006

Transesophageal echocardiography during mitral valve repair underestimates mitral valve area by pressure half-time calculation.

BACKGROUND: Mitral valve repair (MVRr) has become the mainstay of surgical treatment for mitral valvular regurgitation. Evaluation of MVRr by intraoperative transesophageal echocardiography (IOE) has been routinely employed to guide the operation. While the main objective of IOE is to assess for residual mitral regurgitation, it is also important to exclude significant mitral stenosis. Utilisation of pressure half-time (PHT) to estimate mitral valve area (MVA) has been shown to be reliable in normal clinical situations. However, in MVRr, the accuracy of MVA calculation by PHT needs to be ascertained. METHODS AND RESULTS: Data from IOE and post-MVRr transthoracic echocardiography (TTE) from the year 1998 to 2002 were analysed and when required, offline PHT measurements were made. The mean time interval between the two echocardiographic examinations was 10.6 (1 to 56) weeks. In our 36 cases, the IOE MVA was found to be 2.1+/-0.5 cm2, with the corresponding TTE MVA to be 2.7+/-1.0 cm2. MVA by PHT with IOE underestimated TTE findings by 0.6+/-0.9 cm2 (95% CI: -0.85 to -0.24, P=0.001). In 6 patients, the IOE MVA was moderately reduced. Subsequent TTE in these patients showed that the MVA was adequate and was significantly underestimated by IOE in 5 of these patients. In all these cases, IOE underestimated MVA by a margin, which may result in a need to revise the repair. CONCLUSION: We find that IOE immediately after MVRr tends to underestimate MVA by PHT calculation. The underestimation by IOE may have clinical importance in cases when MVA by IOE is moderately reduced. Therefore, pressure half-time measurement should not be used to assess mitral valve areas during mitral valve repair.

Adult↗

PubMed1998

Results of Biocor stentless valve replacement for infective endocarditis of the native aortic valve.

The mid-term results in a selected group of 9 patients with native aortic valve endocarditis managed by aortic valve replacement (with or without complex annular reconstruction) using a totally biological stentless valve are outlined. At a mean follow-up of 48 months, there are currently 7 survivors (2 late noncardiac deaths) with 100% freedom from reoperation, valve-related complication, and endocarditis.

Adult↗

PubMed2001

Opening and closing characteristics of the aortic valve after valve-sparing procedures using a new aortic root conduit.

BACKGROUND: The durability of aortic valve-sparing procedures is negatively affected by increased leaflet stress in the absence of normally shaped sinuses of Valsalva. We compared valve motion after remodeling procedures using a standard conduit and a specifically designed aortic root conduit. METHODS: Echocardiographic studies of the aortic valve dynamics were performed in 14 patients after remodeling of the aortic root (7 standard conduits, group A; 7 new conduits, group B) and in 7 controls (group C). Opening and closing leaflet velocities and percent of slow closing leaflet displacement were measured. Root distensibility and the pressure strain of the elastic modulus were measured at all root levels. RESULTS: Root distensibility and the pressure strain of the elastic modulus were different in group A and B only at the sinuses (p < 0.001). Opening and closing leaflet velocities were not different among groups. Slow closing leaflet displacement was markedly more evident in group B patients (24.2%+/-1.9% versus 2.5%+/-1.9% in group A, p < 0.001) and similar to controls (22.1%+/-7.9%). CONCLUSIONS: The new conduit guarantees dynamic features of the aortic valve leaflets superior to those obtained with standard conduits and more similar to normal subjects.

Aged↗

PubMed2001

Left atrial spontaneous echo contrast in patients with rheumatic mitral valve stenosis in sinus rhythm: relationship to mitral valve and left atrial measurements.

We studied 37 consecutive patients with mitral stenosis in sinus rhythm using transthoracic and transesophageal echocardiography to relate the presence of spontaneous echo contrast (SEC) in the left atrium with mitral valve area and left atrial dimensions. We also compared the value of left atrial area by planimetry with that of left atrial dimension by M mode in predicting presence of SEC and monitored the effect of anticoagulation on SEC. Transesophageal echocardiography demonstrated spontaneous echo contrast in 9/37 (24%) patients and thrombus in none. SEC continued to be present despite anticoagulation. Mitral valve orifice area by pressure half time method (P=0.001) and by planimetry (P=0.01), and left atrial area by planimetry (P<0.05) were predictors to presence of SEC. Left atrial dimension by M mode examination failed to predict SEC. Cut off values were mitral valve orifice </=1.4 cm(2) (agreement 86%) and left atrial area >/=25 cm(2) (agreement 81%). On multivariate analysis mitral valve area was the only independent predictor. SEC persisted despite anticoagulation. This supports the view that more than one mechanism is involved in the development of SEC.

Adolescent↗

PubMed1998

Combined tracheal resection and aortic valve replacement with a cryopreserved aortic valve allograft.

A 69-year-old patient presented with an association of tracheal squamous cell carcinoma and severe aortic valve stenosis. As there was no evidence of metastatic spread a potentially curative resection could be considered. The patient underwent tracheal resection and aortic valve replacement in a one-stage procedure. In light of the potential risk of infection to a prosthetic valve, a cryopreserved aortic valve homograft was implanted. The patient made a full recovery and is doing well after 2 years of follow-up.

Aged↗

PubMed1976

[Incidence and relevance of tricuspid-valve insufficiency in acquired mitral-valve defect. Analysis based on right ventricular angiograms].

To detect tricuspid incompetence (TI) right ventricular angiography was performed in 167 patients suffering from moderate to severe mitral valve disease. Holosystolic reflux of contrast medium to the right atrium through the central part of the tricuspid valve was thought to represent true TI, whereas a jet of contrast medium following the injection catheter and originating from the region of its valve passage was assumed to reflect arteficial regurgitation. True TI was found in 35% of the total group (30% mild to moderate, 5% severe TI). TI was often accompanied by atrial fibrillation (91%), pulmonary hypertension (74%) and reduced contraction of the tricuspid annulus (55%). Since tricuspid regurgitation in mitral valve disease commonly represents "functional" incompetence surgical intervention may be recommandable only in case of severe TI or concomitant valvular stenosis.

Adult↗

PubMed1975

[Thrombosis of the Björk-Shiley valve as an early fatal complication of the prothetic aortic valve replacement (author's transl)].

From a series of 28 patients subjected to aortic valve replacement with the Björk-Shiley tilting disc valve prosthesis 3 cases are reported in which massive thrombosis with valve dysfunction and fatal outcome occurred in the very early postoperative period. The autopsy findings and the examination of the blood coagulation state during the first 24 hours postoperatively disclosed in all 3 cases a hypercoagulability being responsible for the massive clot formation. The early recognition and establishment of the diagnosis of a hypercoagulability state and an immediate anticoagulant therapy with heparin are necessary for preventing such early fatal complications in patients with cardiac valve replacement.

Adult↗

PubMed2002

Failure to detect Chlamydia pneumoniae in aortic valves and peripheral blood mononuclear cells from patients undergoing aortic valve replacement in Norway.

The association of Chlamydia pneumoniae with atherosclerosis is still controversial. Reports from different laboratories have varied widely and "gold standards" for the detection of C. pneumoniae are lacking. In the present study, aortic valves and peripheral blood mononuclear cells from 48 patients undergoing aortic valve replacement were examined for the presence of C. pneumoniae using a nested PCR. C. pneumoniae-specific DNA was not detected in any of the clinical samples. No PCR inhibition was observed by spiking the samples with target C. pneumoniae. A total of 31/46 patients (67%) were seropositive for C. pneumoniae IgG. These results do not support the association of C. pneumoniae with aortic valves and peripheral blood mononuclear cells in patients with atherosclerotic aortic heart valve disease.

Adult↗

PubMed2000

The radiographic quantitation of aortic valve calcification: implications for assessing bioprosthetic valve calcification in vitro.

Calcification of natural aortic and bioprosthetic heart valves is a poorly understood phenomenon that results in valvular obstruction and tissue failure. We describe a non-destructive quantitative computed microtomographic (QCT) technique for determining both calcium content and local calcium distribution within explanted valves. As a reference standard, a dual-energy x-ray absorptiometry (DEXA) system with an accuracy demonstrated to be within 1% of the true calcium mass of test material was used to obtain the total calcium content of 24 human aortic valve cusps recovered at autopsy from patients aged 51-80 years. These cusps were then scanned using our unique volume QCT scanner, with multiple x-ray projections acquired by rotating the explanted tissue through a single axis of rotation. A three-dimensional cross-sectional map was reconstructed for each cusp. Voxel size was 0.003 mm3 and a calibration phantom was used to calculate calcium content. The minimum detection limit for calcium mass was 1 mg within the whole cusp. The DEXA and QCT scans were compared with respect to total calcium content, which ranged from 0 to 15 mg. An excellent correlation between the two independent techniques was demonstrated with an r2 value of 0.94 (p < 0.001). Non-destructive microtomographic CT scanning provided excellent volumetric density measurements, with quantitative 3D images permitting an assessment of any individual area of the cusp for calcium content and spatial distribution. This new approach to valve tissue analysis allows for subsequent histologic assessment.

Absorptiometry, Photon↗

PubMed1986

Aortic valve orifice equation independent of valvular flow intervals: application to aortic valve area computation in aortic stenosis and comparison with the Gorlin formula.

An orifice equation is derived relating the effective aortic valve area, A, the average aortic valve pressure gradient, dP, the stroke volume, SV, and the heart frequency, FH, through considerations of momentum conservation across the aortic valve. This leads to a formula consistent with Newton's second law of motion. The form of the new equation is A = (7.5 X 10(-5)) SV FH2/Pd, where A, VS, FH and Pd are expressed in cm2, ml, s-1 and mmHg, respectively. Aortic valve areas computed with the new orifice equation are found to correlate with those computed by the Gorlin formula in conditions of resting haemodynamic states at a level of r = 0.86, SE = 0.25 cm2, N = 120. The results suggest that the new formula may be considered as an independent orifice equation having a similar domain of validity as the Gorlin formula. The new equation offers the possibility of deriving additional useful haemodynamic relationships through combination with established cardiological formulas and applying it in a noninvasive Doppler ultrasonic or echocardiographic context.

Aged↗

PubMedDate not supplied

Platelets are deposited early post-operatively on the leaflet of a mechanical heart valve in sheep without post-operative anticoagulants or antiplatelet agents. A scanning electron microscopic observation of the pyrolytic carbon surface in a mechanical heart valve.

Pyrolytic carbon has been used for mechanical heart valves as a thromboresistant, wear resistant, and fatigue resistant material. Thrombosis and thromboembolism, however, remain major mechanical heart valve associated complications and may frequently occur during the early post-operative period. In depth morphologic studies on blood-pyrolytic carbon surface interactions are limited. The purpose of this study was to evaluate the blood compatibility of the pyrolytic carbon surface of St. Jude Medical mechanical heart valves that were implanted in the mitral position of sheep without the administration of post-operative anticoagulants or antiplatelet agents for 2, 4, and 6 weeks. Almost the entire leaflet and orifice ring surfaces were observed by scanning electron microscopy. Although the surfaces appeared clean macroscopically, when observed by electron microscopy, the surface were mottled, mainly by solitary platelets and aggregations. There were only a few leukocytes or red blood cells observed. No fibrin clots were observed on the leaflets. The density of platelet deposition was higher in the vicinity of the pivots and near the edges of the leaflets. The sizes of the platelet aggregations decreased with longer duration. The outer surfaces of the pivot guards were covered by various amounts of deposition composed of platelet aggregations and thrombi. Thus, the administration of antiplatelet agents is recommended during the early post-operative period after mechanical heart valve implantation.

Animals↗

PubMedDate not supplied

Anterior mitral valve aneurysm: a subaortic complication of aortic valve endocarditis: a case report and review of literature.

Mitral valve aneurysm is a rare cause of mitral regurgitation, and is usually associated with aortic valve endocarditis. Prompt diagnosis and early surgical treatment can prevent complications such as embolization and rupture of the aneurysm. The authors report a case of aortic valve endocarditis and mitral valve aneurysm in a patient who initially presented with urinary tract infection.

Aortic Valve↗

PubMed2006

Hydrodynamic evaluation of kangaroo aortic valve matrices for tissue valve engineering.

We evaluated the hydrodynamic performance of kangaroo aortic valve matrices (KMs) (19, 21, and 23 mm), as potential scaffolds in tissue valve engineering using a pulsatile left heart model at low and high cardiac outputs (COs) and heart rates (HRs) of 60 and 90 beats/min. Data were measured in two samples of each type, pooled in two CO levels (2.1 +/- 0.7 and 4.2 +/- 0.6 L/min; mean +/- standard errors on the mean), and analyzed using analysis of variance with CO level, HR, and valve type as fixed factors and compared to similar porcine matrices (PMs). Transvalvular pressure gradient (DeltaP) was a function of HR (P < 0.001) and CO (P < 0.001) but not of valve type (P = 0.39). DeltaP was consistently lower in KMs but not significantly different from PMs. The effective orifice area and performance index of kangaroo matrices was statistically larger for all sizes at both COs and HRs.

Animals↗

PubMed1990

Predictors of outcome in patients with prosthetic valve endocarditis (PVE) and potential advantages of homograft aortic root replacement for prosthetic ascending aortic valve-graft infections.

Seventy-five surgically treated patients with prosthetic valve endocarditis were treated at the Stanford University Medical Center. This was a multivariate analysis analyzing both patient related factors, bacteriology, and surgical findings. The conclusions among 10 patients with allograft valves, 20% had an annular abscess; this occurred in 36% of 29 patients with porcine valves, and 65% of these with mechanical prosthesis. Though prevention, again, is key in this especially devastating disease, once infection has been established and an aggressive approach is indicated, it would appear that a homograft re-replacement or free aortic homograft valve replacement can deal with severe tissue destruction to prevent recurrence.

Abscess↗

PubMed1981

A simplified valve formula for the calculation of stenotic cardiac valve areas.

We have simplified the Gorlin formula and have compared our measurements of the aortic or mitral valve area, using the original Gorlin formula and the simplified valve formula in 100 consecutive patients. The valve area was measured by the simplified formula as cardiac output (l/min) divided by the square root of pressure differences across the valve. In patients with aortic stenosis of varying severity there were excellent correlation between the original Gorlin formula and the simplified formula (r = 0.96, y = 0.99x + 0.01, SEE = +/- 0.10, p less than 0.001). The correlation was unchanged when the peak gradient was used instead of the mean gradient in the simplified formula. Excellent correlation was also seen in patients with mitral stenosis of varying severity (r = 0.94, y = 0.97x - 0.02, SEE = +/- 0.19; p less than 0.001). The simplicity of the formula makes it easy to memorize and use.

Adult↗