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A new bioprosthesis for aortic and mitral valve replacement: preliminary evaluation of the Tascon valve.

The Tascon valve, a new porcine bioprosthesis, features a detachable sewing ring designed to facilitate insertion and removal. Between April 1984 and June 1986, we implanted the Tascon valve in 25 patients, 12 of whom underwent aortic valve replacement (AVR), and 13 of whom had mitral valve replacement (MVR). Most of the patients were in NYHA class III or IV. Four MVR patients had had previous mitral valve operations, and three AVR patients required composite graft valved conduits. The valve's screw-locking mechanism worked well in all cases, especially in the AVR cases. There were no hospital deaths, and no significant morbidity or valve-related complications were encountered. One late death occurred 3 months after surgery, owing to causes unrelated to the valve. At the end of the study period, most of the survivors had improved by at least two NYHA functional classes. Postoperative aortic and mitral valve gradients and mitral valve areas, as measured by Doppler methods, were excellent. No significant regurgitation was detected. These favorable results indicate that the Tascon valve is a safe, useful bioprosthesis, with satisfactory hemodynamic characteristics.

Journal Article↗

Chordal-sparing mitral valve replacement: pitfalls and techniques to prevent complications.

When feasible, mitral valve repair is the usual treatment of choice for correction of chronic mitral insufficiency. When valve replacement is required, chordal sparing is the preferred technique. Many investigators have pointed out the merits of preserving the subvalvular apparatus during mitral valve replacement. However, many surgeons hesitate to perform chordal-sparing mitral valve replacement because of its technical complexity and potential interference with mechanical valve leaflet motion. We present a modified technique of chordal-sparing mitral valve replacement to avoid these problems.

Chordae Tendineae↗

Development and use of a remote-controlled mitral valve.

A remote-controlled mitral valve was designed and constructed to occlude the mitral or tricuspid orifice at any time in the cardiac cycle. It is used to study ventricular properties in the anesthetized dog by controlling ventricular filling, atrial properties by controlling atrial emptying and interaction of the two chambers by uncoupling them. The device can produce transient or steady-state perturbations in filling volume which make possible studies of intrinsic control of cardiac output. When filling volume is transiently reduced, stroke volume and end-systolic volume are reduced. A compensatory increase in stroke volume of the next cycles occurs due to increased ventricular preload and reduced afterload. The compensation continues until the lost stroke volume is regained, at which time the system returns to its previous steady state.

Animals↗

Evaluation of suture techniques for mitral valve replacement.

Although periprosthetic leak is presently uncommon after mitral valve replacement, suture line disruption still occurs and may be significant in some patients. Suture technique is obviously an important factor in preventing disruption, but few authors have examined this variable. The purpose of this study was to determine which of four suture methods for mitral valve replacement maximized prosthetic stability in the mitral anulus. Horizontal mattress sutures with subannular pledgets, horizontal mattress sutures with supra-annular pledgets, figure-of-eight sutures, and interrupted simple sutures were compared. A Carpentier-Edwards sewing ring was sutured to the mitral anulus of intact canine left ventricles, each technique randomly assigned to eight hearts. Suture size, number of bites, and annular depth were maintained constant in all groups. Progressively increasing force was applied across the suture line until disruption occurred. The yield force at initial suture disruption was measured by a semiconductor strain-gauge transducer and defined the experimental end point. Subannular pledget-supported sutures required the greatest force (38.4 +/- 0.8 N) to produce prosthetic dehiscence and were significantly more secure than supra-annular pledgets (32.7 +/- 0.5 N). The two suture techniques in which pledgets were used were better than the nonsupported sutures, the mean yield force averaging 28.3 +/- 0.3 N for figure-of-eight and 21.3 +/- 0.7 N for interrupted simple sutures. Although clinical techniques may vary with prosthetic valve design, surgical preference, or pathological anatomy, this study suggests that horizontal mattress sutures with subannular pledgets provide the best prosthetic valve stability during mitral valve replacement.

Animals↗

Double orifice mitral valve associated with endocardial cushion defect.

Duplication of the mitral valve is a rare congenital cardiac anomaly. We encountered a case of duplication of the mitral valve associated with a partial form of endocardial cushion defect in a 6-year-old girl. The mitral orifice was separated by a fibrous tissue and each orifice provided papillary muscle and complete subvalvular mechanisms except for the cleft region. The fibrous tissue also provided a subvalvular apparatus. The cleft was repaired without complication. The short axis view of the two-dimensional echocardiogram demonstrated two separate holes in the mitral valve, which constituted the most obvious diagnostic sign prior to surgery.

Child↗

Results of endocardial radiofrequency ablation of atrial fibrillation during mitral valve surgery.

AIM: The aim of the study is to evaluate the efficacy of thermocontrolled endocardial radiofrequency (RF) ablation for the patients with mitral valve disorder and associated chronic atrial fibrillation during mitral valve replacement operation. METHODS: Between February 2002 and January 2004, 43 patients with mitral valve disease and associated chronic atrial fibrillation underwent mitral valve replacement and thermocontrolled endocardial RF ablation with Cobra RF system flexible probe at Gulhane Military Academy of Medicine, Department of Cardiovascular Surgery. Eighteen of the patients (41.8%) were males, while the remaining 25 (58.2%) were females. The average age of the patients was 44+/-14.21 (18-66) years. Functional capacity of the patients was class II in 15 (34. 9%), class III in 24 (55.8%), class IV in 4 (9.3%) according to the NYHA classification. At the preoperative period all of the patients were evaluated routinely by twelve-lead ECG, chest film and transthoracic echocardiography (TTE). For the patients over 40 years of age, we performed additional coronary angiography to delineate any coronary lesions. The patients were evaluated at months 1, 3, 6 and annually by twelve-lead ECG, TTE and holter monitoring after discharge. RESULTS: There were not any complications related to the performed technique. No operative and hospital mortality were recorded. At the follow-up period for 35 of 43 patients (81.4%) sinus rhythm was restored. The mean follow-up time was 24.3+/-11.2 (12-35) months. CONCLUSION: Endocardial RF ablation especially during mitral valve surgery is a simple technique to be performed. Early and midterm results of the cohort are satisfying.

Adolescent↗

Long-term results of mitral valve repair in active endocarditis.

BACKGROUND: Several investigators have reported the feasibility of mitral valve repair in active endocarditis, but the long-term results are still unknown. METHODS AND RESULTS: We reviewed 37 consecutive patients who underwent mitral valve repair with the Carpentier technique for active endocarditis in our center between 1989 and 1994. This repair involved prosthetic annuloplasty in 31 patients (84%), valve resection in 31 (84%), chordal shortening or transposition in 19 (51%), pericardial patch in 16 (43%), and direct suture of leaflet perforation in 4 (11%). Associated procedures were primarily aortic valve repair or replacement in 11 (30%) and tricuspid repair in 2 (6%). Early complications included 1 operative death (3%; 95% CI, 0 to 15.5) and 1 reoperation for pericardial patch dehiscence. Recurrence of endocarditis was observed in 1 patient (3%; 95% CI, 0 to 16). The 10-year survival rate and freedom from mitral valve reoperation were 80% (95% CI, 66 to 94) and 91% (95% CI, 81 to 100), respectively. At 10 years, most patients (96%) were in good functional status (NYHA class I to II) with no or trivial mitral regurgitation (92%) on echocardiography. CONCLUSIONS: Mitral valve repair using Carpentier's techniques in patients with active endocarditis offers very good long-term results with a low rate of recurrence or reoperation.

Adolescent↗

A clinical profile of mitral valve prolapse syndrome.

Clinical, radiologic, electrocardiographic and 2-dimensional echocardiographic findings of fifty cases of mitral valve prolapse syndrome attending the Pediatric Cardiology clinic of I.C.H. and Childrens Hospital, Medical College, Kottayam over a period of ten years from 1980-1989 are presented. Mitral valve prolapse syndrome (MVPS) accounted for 2% of cardiac problems attending our pediatric cardiology clinic. Isolated MVPS constituted 64% of the cases. The common causes of secondary MVPS were Marfan Syndrome-18%, Atrial Septal Defect-10% and Rheumatic fever-8%. Associations of MVPS included Pectus excavatum (8%), Isolated arachnodactyly (2%) and Straight back syndrome (2%). 2-D echocardiogram demonstrated prolapse of both leaflets of Mitral valve in 44%, Isolated posterior mitral valve leaflet prolapse in 32% and Isolated anterior mitral valve leaflet prolapse in 24% of cases. No complications were seen during follow up.

Echocardiography, Doppler↗

Less invasive techniques for mitral valve surgery.

OBJECTIVE: Minimally invasive surgical techniques aim at reducing the consequences of currently used large incisions, such as bleeding, pain, and risk of infection. Although this new approach developed rapidly in coronary surgery, it remains questionable in mitral valve surgery. This article reports the longest experience with minimally invasive mitral valve surgery, with particular attention to approach and techniques. METHODS: From February 1996, the date of the first case of minimally invasive mitral valve reconstruction, to April 1997, 22 patients with a mean age of 54 +/- 2.7 years were subjected to mitral valve surgery performed with less invasive techniques. Exposure of the mitral valve was achieved through a minithoracotomy (n = 12) or a ministernotomy (n = 10). Video assistance was used in all cases. Peripheral arterial cannulation (n = 21) and venous drainage (n = 22) were used in most cases. RESULTS: In this series, valve surgery consisted in 19 repairs, two replacements, and one closure of a periprosthetic leak. In two cases it was necessary to convert to a larger incision. The average duration of cardiopulmonary bypass was 157 +/- 8.2 minutes, ventilatory assistance 16 +/- 4.6 hours, and intensive care unit stay 2.1 +/- 0.4 days. Two patients required reoperation for bleeding and another for early recurrence of mitral valve regurgitation. There were no deaths and all patients were discharged with normal valve function. At most recent follow-up, all patients were in functional class I, with resumption of normal activity. CONCLUSION: Mitral valve surgery can be performed safely by means of less invasive techniques, but with increased technical difficulty. A low asymmetric median sternotomy seems preferable to an anterior thoracotomy.

Cardiopulmonary Bypass↗

Characteristic pulsed Doppler findings in patients with flail mitral valve.

Pulsed mode Doppler findings in the left atrium were studied in 18 patients with moderate to severe catheterization-proven mitral regurgitation, four with and 14 without flail mitral valve. Atypical markedly turbulent antegrade flow in the left atrium was observed in all four patients with flail mitral valve, whereas the typical retrograde mitral regurgitation pattern of flow was observed in the 14 patients without flail mitral valve. This Doppler pattern appears to be indicative of a flail mitral valve.

Aged↗

Mitral valve stiffening in end-stage heart failure: evidence of an organic contribution to functional mitral regurgitation.

OBJECTIVE: Mitral regurgitation is a complication for many patients with congestive heart failure. Although this regurgitation is considered purely functional, we hypothesize that the alterations in cardiac geometry and function induce dysfunctional remodeling of the mitral valve, which can be demonstrated by alterations in the material behavior of the leaflets and chordae. METHODS: Mitral leaflets and chordae from 23 valves from transplant recipient hearts (11 with dilated and 12 with ischemic cardiomyopathy) and from 21 normal valves (from autopsy) were mechanically tested. RESULTS: Radially oriented anterior mitral leaflet strips from failing hearts were 61% stiffer and 23% less viscous on average than those from autopsy control hearts. The mean stiffness of circumferentially oriented anterior leaflet strips was 50% higher than that of control hearts. Leaflet extensibility was reduced 35% overall. Likewise, the failing heart chordae were an average of 16% stiffer (all P < or = .05). CONCLUSIONS: Mitral valves in congestive heart failure have significantly altered mechanics that suggest that the tissue is permanently distended and fibrotic and might be unable to stretch sufficiently to cover the valve orifice. These material changes in the valve tissues accompany the biochemical alterations in extracellular matrix composition that we have previously reported. Our finding of leaflet and chordal remodeling suggests that mitral regurgitation in patients experiencing heart failure might not be purely functional and that these mitral valves should not be considered normal. Moreover, there are implications for strategies of mitral valve surgery or percutaneous approaches in this patient population.

Chordae Tendineae↗

[Surgical treatment of left ventricular aneurysm with acute myocardial infarction associated to mitral valve stenosis: a case report].

A 55-year-old female afflicted with mitral valve stenosis and atrial fibrillation was admitted to our hospital complaining of chest pain, ST elevation of ECG (V2-5) and elevated CPK value were recognized. She was diagnosed as having acute myocardial infarction, and percutaneous transluminal coronary recanalization was performed immediately. The coronary angiogram showed occlusion by the thrombus at the proximal left anterior descending branch (#7), even, left ventriculogram showed ventricular aneurysm on the anterior wall. But these lesions could not be recanalized by 960,000 IU urokinase administration. She underwent aneurysmectomy and mitral valve replacement with 27 mm SJM prosthesis. When mitral valve stenosis accompanied with left ventricular aneurysm we considered in order to improve left ventricular function, it is necessary to undergo not only mitral valve operation but left ventricular aneurysmectomy aggressively.

Female↗

Misleading noninvasive signs of Bjork--Shiley mitral valve dysfunction.

Three months after receiving a Bjork--Shiley mitral valve prosthesis, a patient experienced acute gastronintestinal bleeding associated with heavy alcohol intake and poor compliance with oral anticoagulation therapy. As a result of the gastrointestinal bleeding, treatment with warfarin was discontinued. Ten months later, the patient presented with symptoms of transient cerebral ischemia. Despite demonstrated loss by phonocardiography of the previously well-recorded opening click and echocardiographic suggestion of a thrombosed prosthetic mitral valve, no thrombosis or dysfunction of the prosthetic mitral valve was revealed at reoperation.

Diagnosis, Differential↗

Instantaneous mitral valve leaflet velocity and its relation to left ventricular wall movement in normal subjects.

Echocardiograms showing mitral valve leaflets, interventricular septum, and posterior wall of the left ventricle simultaneously were recorded at a paper speed of 100 mm/s in 20 normal subjects. These records were manually digitized and a computer was used to derive mitral valve velocity, left ventricular dimension, and its rate of change continuously throughout a single cardiac cycle. The pattern of instantaneous mitral valve velocity with respect to time was similar in all subjects studied, showing a peak opening rate of 400 +/- 60 mm/s (mean +/- 1 SD), and continuously changing velocity throughout the period of mid-diastolic closure. The peak diastolic closure rate was 250 +/- 60 mm/s and thus appreciably higher than average velocities obtained by manually measuring the slope. A close time relation existed between mitral valve and left ventricular wall movement in early diastole. Forward movement of the anterior leaflet began 1 +/- 6 ms after the onset of outward wall movement, and peak velocity was reached 2 +/- 7 ms after the maximum rate of change of dimension. Later, a discontinuity in wall movement at the end of rapid filling preceded a corresponding discontinuity in the mitral valve velocity tracing by 5 +/- 10 ms. The technique, therefore, allows continuous measurement of mitral valve velocity, and demonstrates its close relation to left ventricular wall movement during diastole.

Adolescent↗

Non-invasive assessment of mitral valve area during percutaneous balloon mitral valvuloplasty: role of real-time 3D echocardiography.

BACKGROUND: In the last decade, multiple studies depicted discrepancies between mitral valvular orifice area (MVA) measurements obtained with the pressure half-time (PHT) method and invasive methods during the immediate post-percutaneous mitral valvuloplasty (PMV) period. Our aim was to assess the accuracy of Real-Time 3D echo (RT3D) to measure the MVA in the immediate post-PMV period. The invasively determined MVA was used as the gold standard. METHODS AND RESULTS: We studied 29 patients with rheumatic mitral stenosis from two centres (27 women; mean age 48.2+/-11.3 years), all of which had underwent PMV. MVA was calculated before and after PMV using the PHT method, 2D echo planimetry, RT3D echo planimetry and invasive determination (Gorlin's method). The RT3D MVA assessment showed a better agreement with the invasively derived MVA before and in the immediate post-PMV period (Bland-Altman analysis: Average difference between both methods and limits of agreement: 0.01 (-0.31 to 0.33) cm(2) and -0.12 (-0.71 to 0.47) cm(2)) before and immediately after the PMV, respectively. CONCLUSIONS: RT3D is a feasible and accurate technique for measuring MVA in patients with RMVS. It has the best agreement with the invasively determined MVA, particularly in the immediate post-PMV period.

Adult↗