Free-floating left atrial thrombus formed in a few weeks in a patient with a normal mitral prosthesis.
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Bioprosthesis↗
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Results for “HEART VALVE PROSTHESIS”
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Porcine stentless valve/bovine pericardial conduit for right ventricle to pulmonary artery.
BACKGROUND AND OBJECTIVES: We assessed the long-term outcome of a glutaraldehyde-preserved bovine pericardial conduit containing a stentless composite porcine aortic valve. METHODS: Between November 1985 and May 1995, 33 stentless porcine valves attached to bovine pericardial conduits were used in 33 patients with complex congenital cardiac malformations. These patients required a conduit between the right ventricle and the pulmonary artery because of an absent or inadequate pulmonic artery. All patients were approached by midsternotomy. One patient with pulmonic atresia and an interventricular septal defect required left thoracotomy for ligation of collaterals. RESULTS: Of the initial 33 patients, clinical follow-up was performed in 23 discharged patients (70%) for 1.7 to 10.5 years. The echo-Doppler analysis performed in each of the 23 followed patients showed excellent conduit and valve function in all but 4 patients, in whom a valve gradient of 60 mm Hg was noted. There was no tissue structural failure noticed in this study. CONCLUSIONS: The SJM Biocor (Belo Horizonte, Brazil) bovine pericardial stentless valved conduit performed well as a substitute for the right ventricle to pulmonary artery connection.
Adolescent↗
[Correction of the aortic valve without a prosthesis].
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Aortic Valve↗
Implantation of cryopreserved mitral allograft into the tricuspid position in an experimental study in sheep: technical aspects of implantation and immediate results evaluated by epicardial echocardiography.
AIMS: Cryopreserved mitral allograft valve (MAV) offers theoretical advantages over conventional mechanical or biological prostheses in tricuspid position, especially in infectious endocarditis patients. MAV processing and tricuspid valve (TV) replacement in a sheep model is described. METHODS AND RESULTS: In 20 adult sheep, MAV were harvested, processed and cryopreserved. One month later, recipient's TV were excised and the MAVs were transplanted into the tricuspid position in 13 sheep, under general anaesthesia, via a right thoracotomy, with an extracorporeal circulation (ECC) and cardioplegic heart arrest. Both MAV papillary muscles were anchored into the right ventricular wall by transmural stitches and the MAV anulus was sewn into the recipient's tricuspid anulus. After weaning from ECC, the anatomy and function of the MAV in the tricuspid position was assessed by epicardial echocardiography. The average duration of the ECC was 58 minutes (42-88), the cardioplegic heart arrest was 36 minutes (28-45). Weaning from EEC was always uneventful. Right atrial & pulmonary artery pressure measurements and epicardial echocardiography documented good function of all MAVs. CONCLUSION: MAV remained mechanically strong enough for implantation into the tricuspid position. Reproducible technique of MAV transplantation into the tricuspid position with excellent early postoperative haemodynamic performance was developed.
Animals↗
[Acute mitral valve insufficiency caused by a broken mitral valve prosthesis].
Breaks in a mechanical heart valve prosthesis with resulting acute valvar insufficiency are extremely rare. The case is reported of a 49-year-old man who, two-and-a-half years after implantation of a mitral valve prosthesis, suddenly went into acute cardiogenic shock, after having been in good health since the valve replacement. Although the symptoms were unequivocal, the correct diagnosis was not made for more than 40 hours. Emergency re-operation could not prevent death from severe interstitial pulmonary oedema with hyaline membranes. Within the last 20 years 25 similar cases have been reported.
Acute Disease↗
Effect of cutting second-order chordae on in-vivo anterior mitral leaflet compound curvature.
BACKGROUND AND AIM OF THE STUDY: Leaflet curvature determines leaflet stress. In order to assess the influence of second-order chordae (2 degrees CT) on anterior mitral valve leaflet (AMVL) geometry, AMVL curvature was measured before (Baseline) and after (CUT) cutting the 2 degrees CT. METHODS: Miniature radiopaque markers were sutured onto the AMVL in eight sheep: four along the central-meridian from mid-septal annulus to the free-margin; and one each at the 2 degrees CT insertion. Biplane videofluoroscopic data were acquired (open-chest) before and after CUT. Marker-triplet 3-D coordinates were used to calculate radii-of-curvature at LVPmax along the central-meridian (ROCm) and across the AMVL belly (commissure-commissure axis, ROCc-c). RESULTS: CUT did not change LVPmax (111 +/- 12 versus 106 +/- 11 mmHg; p = 0.19). At baseline, the AMVL central-meridian had compound curvature: Convex to the left ventricle near the annulus (-ROCm) and concave near the free-margin (+ROCm). After CUT, the AMVL flattened: ROCm increased near the annulus (from -1.37 +/- 0.52 to -12.58 +/- 29.04 cm; p = 0.02), but did not change near the edge. In the commissure-commissure axis, ROCc-c was concave to the left ventricle at baseline and increased after CUT in all eight animals. In five sheep, ROCc-c was increased (from 1.93 +/- 1.01 to 2.80 +/- 1.36 cm; p = 0.03), but in three sheep ROCc-c was increased and inverted (from 3.65 +/- 2.17 to -1.72 +/- 0.53 cm; p = 0.03), becoming convex to the left ventricle. CONCLUSION: Compound curvature along the AMVL central-meridian appears to be an intrinsic leaflet property that persists even without support from second-order chordae, whereas concave curvature in the commissure-commissure axis is more dependent on intact second-order chordae. Leaflet compound curvature must be incorporated into future finite element models to characterize leaflet stresses accurately. The importance of second-order chordae in maintaining leaflet shape must be considered during mitral repair. A larger ROC increases leaflet stresses, while reversal of ROC changes tensile stress to compressive stress; this might trigger deleterious leaflet remodeling after chordal cutting.
Animals↗
Is device closure for direct access valved stent implantation safe?
OBJECTIVE: Despite the progress made in the development of valved stents for trans-apical valve replacement, a reliable closure of the access orifice remains a major issue. The present study was designed to evaluate if device closure of the ventricular wall is safe. MATERIALS AND METHODS: Transventricular access for pulmonary valve replacement was simulated with a 26F sheath and the resulting orifice was closed with an Amplatzer Muscular VSD Occluder (AMuscVSDO) in chronic sheep experiments (body weight 45-48 kg). Mean procedure time, blood loss, and standard hemo-dynamics were recorded. The animals were sacrificed electively and the histopathological changes in and around AMuscVSDO in the right ventricular wall were systematically studied by semi-quantitative analysis of collagenisation, inflammatory response and 'resorptive' process. RESULTS: Mean procedure time was 31+/-10.7 min, blood loss was 22.5+/-8.7 ml, heart rate was 123+/-22.6 bits/min before and 128+/-28.7 bits/min after, mean arterial blood pressure was 88+/-16.7 mm Hg before and 82.6+/-18.3 mm Hg after the procedure. Mean survival was 5.3 weeks. The collagen and scar formation studies revealed three different periods: (1) initial fibrosis (0-3 weeks); (2) so-called 'capsulation' (3-9 weeks after the implantation of the Occluder); and (3) final remodelling and differentiation (9 weeks). The fabric inside the Occluder played the role of a collagenisation promoter, active from the 3rd week till it vanishes. Inflammation plays a role as a temporary reaction (0-3 weeks) during the healing process, with no signs of any active, focal or circumscribed, myocardial damage. CONCLUSIONS: (1) The closure of the free ventricular wall perforation with AMuscVSDO is safe due to the scar tissue resulting from the healing process around and in the device. (2) The myocardial healing around and inside an implanted AMuscVSDO represents two processes: extensive fibrosis ensues around metallic wires with the progression towards the inside of the myocardium, whereas inside AMuscVSDO the loose connective tissue fills the myocardial lesion. During cicatrisation, the fabric elements of AMuscVSDO act as the ground for collagen formation and fibroblast proliferation. (3) The cicatrisation processes after ventricular AMuscVSDO implantation show remodelling, with rearrangement of collagen fibres architecture and distribution.
Absorbable Implants↗
"Mosaic" medtronic bioprosthetic valve replacement clinical results and hemodynamical performance.
BACKGROUND: We report the mid-term results of a prospective trial of a new bioprosthetic valve. The Mosaic bioprosthesis consists of porcine aortic valve that has been cross linked ed in glutaraldehyde solution under zero-pressure fixation and treated with alpha amino oleic acid to reduce the potential for calcification. METHODS: Mosaic bioprosthetic valve replacement was performed in 67 consecutive patients between January 1995 and August 1998. There were 37 patients having aortic valve replacement (AVR) and 30 having mitral valve replacement (MVR) who entered this study. The patients age ranged 56 to 86 years (mean 74.9); 38 were female and 29 were male; 44 were in NYHA grade 3 and 21 were NYHA grade 4. All mitral valve replacements were performed with total preservation of subvalvular apparatus. Echocardiographic assessment of valve and LV function were performed on 7th day, 6 months 1,2 and 3 years. RESULTS: There was no hospital mortality. 3 year survival was 85.9+/-5.9% for AVR and 100% for MVR. Freedom from antithromboembolic related haemorrhage has been 96.7% for MVR and 91.9% for AVR. Freedom from the transient neurological event was 96.7+/-3.3% for MVR and 100% for AVR Freedom from structural valve failure, permanent thromboembolism, thrombosis or endocarditis has been 100% for both AVR and MVR. In AVR group left ventricle mass, left ventricle mass index significantly decreased, when cardiac index and effective orifice area increased significantly during study period. Transvalvular gradient did not change. In MVR group transvalvular gradient, effective orifice area and cardiac index did not change. CONCLUSIONS: The valve was user friendly. The early results are very satisfactory. Echocardiography measurements after aortic valve replacement are showing very marked late postoperative remodelling of left ventricle. After mitral valve replacement there were exceptionally low transvalvular gradients, no left ventricle outflow tract obstruction.
Aged↗
Off-pump replacement of the pulmonary valve in large right ventricular outflow tracts: a hybrid approach.
BACKGROUND: Percutaneous pulmonary valve replacement has recently been introduced and is under investigation in humans. This technique is, however, limited to patients with a right ventricular outflow tract that does not exceed 22 mm in diameter. We report our experience of off-pump pulmonary valve replacement using a hybrid approach in animals with large right ventricular outflow tracts. METHODS: Eight ewes were included in the protocol and were equally divided into 2 groups. A left thoracotomy was first performed, and the main pulmonary artery was banded by using 2 radiopaque rings with a diameter of 18 mm that allowed for further pulmonary valve replacement. We then intended to implant a valved stent either percutaneously (group 1) or through a transventricular approach (group 2). All animals were killed after valve implantation. The operation allowed the pulmonary diameter to be reduced from 30 to 17.6 mm. RESULTS: The right ventricular pressure did not significantly increase after reduction of the pulmonary artery diameter (25 vs 36 mm Hg). Subsequent pulmonary valve replacement through a percutaneous or a transventricular approach was always possible without any requirement for extracorporeal circulation. All devices were successfully delivered inside the pulmonary artery banding and were functioning perfectly at early evaluation. CONCLUSIONS: Implantation of a pulmonary valve is possible in ewes through a hybrid approach when the right ventricular outflow tract exceeds 22 mm in diameter. This involves both surgeons and interventionists and allows for a staged procedure in which the valvulation is performed percutaneously or, for a combined hybrid approach, in which the valve is implanted off pump transventricularly during the same operation.
Animals↗
Aortoventriculoplasty in a patient with complex left ventricular outflow tract obstruction, mitral valve stenosis and aneurysm of the ascending aorta.
We describe a new method of aortoventriculoplasty in a patient with calcified mitral stenosis, aortic valvular stenosis, severe left ventricular outflow tract obstruction, and aneurysm of the ascending aorta. This complex pathology was successfully treated with replacement of both the valves and a tubular dacron graft. The proximal end of the dacron tube was tailored as a patch for the repair of the ventricular septum and the aortic root, and the distal end was anastomosed to the distal ascending aorta. The patient had an uneventful recovery and postoperative echocardiography showed no significant residual gradient on the left ventricular outflow tract.
Aortic Aneurysm, Thoracic↗
Influence of patient-prosthesis mismatch on myocardial mass regression and clinical outcome in physically active patients after aortic valve replacement.
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Actuarial Analysis↗
Surgical management of right ventricular dysfunction late after repair of tetralogy of fallot: right ventricular remodeling surgery.
With the increasing number of late survivors of repair of tetralogy of Fallot, surgical management of patients with right ventricular (RV) dysfunction and limited exercise capacity has become a more frequent problem. The wide variability in clinical status, extent of RV dilatation, and dysfunction at the time of presentation for surgical intervention has resulted in disparate surgical results after pulmonary valve insertion. With increasing use of magnetic resonance imaging, quantitative measures of RV volumes, function, and pulmonary regurgitant fraction have enabled a more systematic analysis of results. While there is a group of patients that responds favorably to pulmonary valve insertion, there is also a large subgroup that does not; this requires further analysis of the mechanisms responsible. We have developed a surgical approach to this latter group of patients, which incorporates the concepts of ventricular remodeling or restoration developed for the left ventricle following myocardial infarction. Preliminary results indicate that this procedure is equally safe to pulmonary valve insertion alone, and may result in improved RV function.
Adolescent↗
Summary of the Mayo Clinic experience with direct left ventricular puncture.
Hemodynamic assessment of patients with prosthetic valves can be challenging. Noninvasive techniques may be limited by interference from the prosthetic material, whereas access to the left ventricle for direct pressure measurements often is not possible using common methods. The technique of direct, percutaneous left ventricular puncture has been proven to be a safe method that often provides needed data to help manage difficult clinical situations. We report our 8-yr experience with this technique for assessment of patients with valvular prostheses. Direct left ventricular puncture is a safe technique in patients with prior cardiac surgery and provided significant diagnostic information in the set of patients with multiple valvular prostheses.
Aortic Valve↗
Reconstruction of the RVOT with valved biological conduits: 25 years experience with allografts and xenografts.
OBJECTIVE: The reconstruction of the RVOT in congenital heart disease often requires the implantation of a valved conduit. Although allografts are considered the conduit of choice their availability is limited and therefore xenografts are implanted as well. We compared the long-term durability of both grafts in the RVOT over a 25-year period. METHODS: Between January 1974 and August 1999, 505 patients (median age 4.0 years, range 2 days-31 years; median weight 14.5 kg, range 2.2-76.6 kg; median body length 103 cm, range 48-183 cm) with congenital malformations (PA 25.3%, TOF 14.5%, TOF+PA 2.4%, DORV 4.2%, TGA+PS 8.7%, TAC 24.8%, and other 20.2%) received their first valved conduit (174 xenografts: median diameter 14 mm, range 8-27 mm; 331 allografts: median diameter 19 mm, range 8-30 mm). RESULTS: Follow-up is 3017 patient-years. The 10-year survival-probability for all patients. was 66% with a mean reoperation-free interval for conduit-exchange of 13.3 years (mean reoperation-free interval for allografts, 16.0 years; mean reoperation-free interval for xenograft, 10.3 years). One hundred and thirteen patients underwent a conduit-exchange, mostly due to conduit stenosis. Fourteen patients had a second exchange and three patients a third exchange. For patients with conduit diameters <18 mm (n=235: allograft n=116, xenograft n=119; median age 9 months, range 0-27.3 years), the mean reoperation-free interval was 11.2 years (mean interval allograft, 13.1 years; mean interval xenograft, 8.6 years, P=0.03). For conduit diameters >/=18 mm (n=270: allograft n=215, xenograft n=55, median age 7.4 years, range 0-34.3 years) the mean interval from freedom of conduit exchange was 15.1 years (for allografts 14.1 years, for xenografts 12.5 years, P<0.01). Comparing xenografts to allografts, we found no difference in patient survival probability (P=0.62). There was no significant difference between antibiotic (n=198) preserved vs. cryopreserved (n=133) allografts (P=0.06). Blood group compatibility of allografts to recipients had no significant influence on allograft function (P=0.42). The donors allograft origin, whether aortic or pulmonary valve, had also no significant influence on allograft long-term function (P=0.15). CONCLUSION: For the reconstruction of the right ventricular outflow tract (RVOT) allografts show significantly better long-term durability than xenografts regardless of the age at implantation and the diameter.
Adolescent↗
Long-term outcomes after valve replacement for low-gradient aortic stenosis: impact of prosthesis-patient mismatch.
BACKGROUND: The long-term outcomes of patients with low-gradient aortic stenosis (LGAS) after aortic valve replacement (AVR) are poorly defined. The purpose of this study was to define the long-term outcomes of LGAS patients after AVR and to evaluate the potential impact of prosthesis-patient mismatch (PPM) in these patients. METHODS AND RESULTS: A cohort of 664 patients undergoing AVR for aortic stenosis after 1990 were followed-up prospectively with annual clinical assessment and echocardiography (total follow-up 3447 patient-years; mean follow-up 5.2+/-3.3 years). LGAS was defined as an aortic valve area <1.2 cm2, a mean transvalvular pressure gradient <40 mm Hg, and a left ventricular (LV) ejection fraction <50%, and was present in 79 patients. Rates and correlates of survival, freedom from congestive heart failure (CHF), and LV mass regression after AVR were determined using multivariate regression methods. Ten-year survival and freedom from CHF after AVR were 72.7+/-7.5% and 68.2+/-9.5%, respectively, for patients with LGAS, compared with 89.6+/-1.8% and 84.1+/-4.2% for patients without LGAS (hazard ratio [HR] for death and postoperative CHF, 3.1+/-1.1 and 2.7+/-0.9, respectively; P<0.01). In LGAS patients, PPM, defined as an indexed effective orifice area < or = 0.85 cm2/m2, was independently associated with increased rates of CHF (HR, 3.6+/-2.2; P=0.039), impaired LV mass regression (P=0.037), and a trend toward increased late mortality (HR, 3.0+/-1.9; P=0.084). CONCLUSIONS: Patients with LGAS have worse long-term outcomes after AVR compared with patients without LGAS. PPM adversely affects the long-term outcomes of LGAS patients and should be avoided in this population.
Aged↗
Clinical outcomes and indicators of normalization of left ventricular dimensions after Ross procedure in children.
Between 1993 and 2000, 50 patients (age range, 1 month to 18 years) who had left ventricular outflow tract (LVOT) disease and had undergone a Ross procedure were assessed using echocardiography. Aortic annulus size, valvular gradient, valve insufficiency, LV dimensions at end-systole and end-diastole, LV interventricular septal and posterior wall thickness, and LV mass index (LVMI) were measured. There was 1 early and 2 late deaths, and 5 reoperations. Aortic annulus size increased and degree of aortic insufficiency (AI) decreased, as did LV internal dimensions and LVMI. Peak pressure gradients declined from 73 +/- 18 mm Hg to 7 +/- 7 mm Hg, and LVMI regressed (167 +/- 6 g/m(2) v 108 +/- 6 g/m(2), P <.001) after 3 years. The degree of AI ranged from none to mild, and no patient has LVOT stenosis. Regression of LV dilatation and hypertrophy, good autograft valve function and durability, and a high survival rate suggest that the Ross procedure is preferred for most children who require aortic valve replacement.
Adolescent↗
Left ventricular free wall rupture following mitral valve replacement.
During a 10-year period, 110 patients underwent mitral valve replacement (MVR). We experienced three left ventricular ruptures among these patients. Two had a type I immediate rupture, and one had a type III delayed rupture. Two patients (type I, III) survived after repair of the rupture. It was possible to control bleeding by manual compression with oxidized cellulose, collagen mat and fibrin glue with or without external mattress sutures. Following the repair, an intra-aortic balloon pump and sedative agents were used in both patients. In the other patient with a type I early rupture, control of bleeding was attempted by external direct suture using Teflon felt. The bleeding was controlled by this repair and the use of a left ventricular assist device, but the patient died of a brain infarction 5 days after the operation. The manual compression technique using oxidized cellulose, collagen mat and fibrin glue may be useful for minor lacerations, and for reinforcing repairs. The intra-aortic balloon pump and continuous sedation are useful for unloading the ventricle and reducing the tension on repairs.
Aged↗
Long-term durability of three mechanical valves.
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Aortic Valve↗