An unusual case of bioprosthetic mitral valve thrombosis

Bioprosthetic valve thrombosis and related embolism are considered extremely unlikely, thus allowing most patients to avoid long-term anticoagulation. There is, however, limited experience in the diagnosis and treatment of such a condition. We present the case of a patient with a porcine mitral bioprosthesis who presented with acute thrombosis with unusual echocardiographic features. A favorable outcome was observed after conventional anticoagulant treatment.     

Acute early failure of a bioprosthesis after mitral valve replacement with completely preserved annuloventricular continuity

We report a case of acute early bioprosthetic failure after mitral valve replacement with completely preserved annuloventricular continuity. A 77-year-old man with left ventricular dysfunction underwent double valve replacement with Carpentier-Edwards pericardial bioprostheses. Routine postoperative echocardiography revealed 1.4 cm² of estimated mitral valve area, and computed tomography revealed a large thrombus in the left atrium. Transesophageal echocardiography showed a restricted opening of the bioprosthetic leaflets. After a month of strict anticoagulation therapy, cusp mobility improved, with a calculated mitral valve area of 3.5 cm²; and the left atrial thrombus had almost disappeared 2 months after initiation of therapeutic anticoagulation. Surgeons should be watchful for bioprosthetic thrombosis in patients with left ventricular dysfunction who undergo mitral valve replacement with a preserved mitral subvalvular apparatus.     

Prosthetic valve thrombosis: twenty-year experience at the Montreal Heart Institute

BACKGROUND: Prosthetic valve thrombosis is a life-threatening complication. We reviewed the incidence, risk factors, and treatment strategies of this rare complication. METHODS: From February 1981 through January 2001, 5430 valve operations were performed in 4924 patients at the Montreal Heart Institute. Of this cohort, 39 patients presented with prosthetic valve thrombosis and had complete follow-up data obtained from our prospective valve clinic database. RESULTS: In this series 82% of patients were women, and the mean age was 58 +/- 11 years. The underlying pathology involved the mitral valve in 75% of cases. Most prosthetic valve thromboses occurred with mechanical prostheses (95%). The time interval from first valve replacement to prosthetic valve thrombosis was 39 +/- 42 months. The most frequent clinical presentation was severe congestive heart failure (44%). On prosthetic valve thrombosis presentation, the international normalized ratio was less than 2.5 in 54%, with inadequate anticoagulation management in 26% and poor compliance in 26%. Eighty-two percent of patients underwent a surgical procedure, consisting of thrombectomy in 47%, mitral valve replacement in 47%, and aortic valve replacement in 6% of patients. The 30-day operative mortality and total in-hospital mortality after prosthetic valve thrombosis were 25% and 41%, respectively. The 10-year actuarial survival after prosthetic valve thrombosis was 46% +/- 10%. CONCLUSION: Inadequate level of anticoagulation is the most important factor involved in the pathogenesis of prosthetic valve thrombosis. The overall mortality rate despite surgical treatment remains high. This study underscores the importance of meticulous surveillance of anticoagulation therapy in patients with prosthetic valves.     

Thrombosed Bj?rk-Shiley standard disc mitral valve prosthesis

Between April 1980 and June 1986, 274 patients underwent mitral valve replacement (MVR) with the Bj?rk-Shiley (BS) standard disc mitral valve prosthesis at the American University of Beirut Medical Center (AUBMC). Eleven patients (3.9%) presented 6-41 months after surgery with prosthetic valve dysfunction due to thrombosis. Inadequate control of anticoagulation was the major factor predisposing to thrombosis in all except one. All patients had documented rheumatic valvular disease. Nine patients were operated on an emergency basis and two died before any surgical intervention was possible. Thrombectomy was performed on six patients with four survivors and MVR in three with two survivors. Two patients died intraoperatively (22%). Three pregnant patients underwent mechanical declotting; pregnancy was terminated by abortion in 2 and by caesarean section and live birth in one. We conclude that implantation of the BS mitral valve prosthesis mandates emphasis on anticoagulation and the difficulty encountered with continuous anticoagulant therapy in pregnancy.     

A comparison of replacement and reconstruction in patients with mitral regurgitation

The factors that make mitral reconstruction an attractive alternative to valve replacement are increased anatomical valve orifice, preservation of the valvular apparatus, improved longevity over porcine xenografts, and no requirement for long-term anticoagulation. In our experience the majority of patients with mitral regurgitation have degenerative valve disease. This comparative series of patients operated on over a 10 year interval includes 72 with replacement and 112 with reconstruction. The average cross-clamp times were 69 minutes for reconstruction and 44 minutes for replacement. The hospital mortalities were 3.6% and 18.1%, respectively. Postoperative valve areas as determined by Doppler echocardiography were 2.69 cm2 for replacement and 2.67 cm2 for reconstruction (p = 0.9). The valve failure rate was 2.0% per patient-year for reconstruction and there were no failures in the replacement group. The reoperation incidence for reconstruction was 20% at 10 years. The remaining patients, although clinically well, had varying degrees of stable, nonprogressive mitral regurgitation. Forty-five percent had mild to trivial regurgitation detectable by echocardiographic studies. The decision between mitral valve reconstruction and mitral valve replacement remains a highly controversial issue. The failure of our data to demonstrate superior valve function for patients with mitral regurgitation undergoing valve reconstruction suggests a need for careful analysis of reconstruction with respect to effective valve orifice and incidence of regurgitation.     

Emergency pulmonary autograft mitral valve replacement in a child

Mitral valve replacement in small children imposes significant clinical difficulties because of the relatively small mechanical prosthetic valves required and the need for lifelong anticoagulation therapy. A child weighing 10.4 kg presented with thrombosis of her 19-mm mechanical mitral prosthesis 4 weeks after implantation despite appropriate oral anticoagulation therapy. An emergency mitral valve replacement with a pulmonary autograft was successfully performed with encouraging short-term results.     

The Ross II procedure: pulmonary autograft in the mitral position

The surgical management of mitral valve disease in women of childbearing age, young patients, and children with congenital mitral valve defects is made difficult by the prospect of lifelong anticoagulation. We suggest the use of a pulmonary autograft in the mitral position (Ross II procedure) as an alternative surgical technique. We present a review of the literature, historical perspectives, indications, selection criteria, and surgical technique for the Ross II procedure. Our literature search identified 14 studies that reported results from the Ross II operation. Performed in 103 patients, the overall in-hospital mortality was 7 (6.7%), with a late mortality of 10 (9%). Although further research is needed, current evidence suggests the Ross II operation is a valuable alternative in low-risk young patients where valve durability and the complication rate from other procedures is unsatisfactory and anticoagulation not ideal.     

Prevention of thromboembolism using aspirin after mitral valve replacement with porcine bioprosthesis

The thromboembolic rate of 768 patients who were treated only with aspirin after mitral valve replacement or mitral plus aortic valve replacement with porcine bioprostheses was evaluated. We analyzed the thromboembolic rate for the whole series and for subgroups of patients categorized by atrial fibrillation, giant left atrium, left atrial thrombosis, and dosage of aspirin (1 gm daily or 0.5 gm every 48 hours). The total embolic rate was 1.4% (11/768). No patient in sinus rhythm had an embolic event. The embolic rate for patients in atrial fibrillation was 1.9% (11/583). There were no embolic events in 31 patients with a giant atrium. An embolic event occurred in 1 of 42 patients with atrial thrombosis (2.4%). Patients treated with 1 gm of aspirin daily had a 3% embolic rate (9/295) while the incidence was 0.4% (2/473) in those treated with 0.5 gm every 48 hours (p less than 0.01). Administration of aspirin after mitral valve replacement with a bioprosthesis is a very effective treatment for prevention of thromboembolism. In our experience, this treatment provides protection equal to or better than that offered by oral anticoagulants for patients in atrial fibrillation as well as for patients with a giant atrium or atrial thrombosis at operation. The dosage and timing of aspirin administration may markedly affect the result of this type of treatment. Oral anticoagulation with coumarin derivatives may not be appropriate after mitral valve replacement with a bioprosthesis, and platelet antiaggregates should be used for this purpose in the future.     

Successful nonsurgical therapy of mural thrombosis of the left atrium after mitral valve replacement

Mural thrombosis of the left atrium is a complication of mitral valve replacement. In this report we present a case of mural thrombosis of the left atrium after mitral valve replacement treated successfully without surgical intervention.     

Combined superior-transseptal approach to the mitral valve]

We report a technique to improve exposure of the mitral valve apparatus. This technique that combines superior left atriotomy and interatrial septotomy can be helpful in patients with a small left atrium and reoperation. It has been used effectively in five patients and potential complication with this procedure has not occurred. The operative technique and indication are discussed in this paper.     

A case of thrombosed St. Jude Medical valve 16 years after initial mitral valve replacement]

We report successful surgery for a thrombosed St. Jude Medical (SJM) valve 16 years after the initial mitral valve replacement even under conditions of satisfactory anticoagulation therapy. A 61-year-old-female had intermittent claudication and was admitted to our hospital for examination. The prosthetic valve sounds were normal to auscultation and the left ankle-pressure index was decreased to 0.6. Transthoracic echocardiography revealed no mitral regurgitation and a mean mitral valve gradient of 6-7 mmHg. Furthermore, transesophageal echocardiography revealed that one of the leaflets of the prosthetic valve was entirely immobilized at the closing position and a mobile soft tissue mass, 5 mm in diameter, was detected at the atrial side of the obstructed leaflet. Although 96,0000 IU of urokinase was administered intravenously for a week, we could not confirm any change in leaflet mobility. At the time of surgery, the posterior leaflet of the SJM valve, which was implanted at an anatomical orientation, was obstructed at the closing position with old and fresh thrombi. We decided upon replacement with a CarboMedics 29 M prosthetic valve. Postoperative medication consisted of warfarin plus low-dose aspirin. Generally, valve thrombosis occurs within 5 years after valve replacement. However, valve thrombosis is possible even in a reliable SJM valve and as long as 16 years after replacement. Therefore, the implantation of an SJM valve at an anti-anatomical orientation might lower the incidence of valve thrombosis in addition to life-long anticoagulation therapy.     

The risk of thromboembolism and hemorrhage following mitral valve replacement. A comparative analysis between the porcine xenograft valve and Ionescu-Shiley bovine pericardial valve

To ascertain the risk of thromboembolism and anticoagulant-related hemorrhage following mitral valve replacement with bioprostheses, an 8 year retrospective study between two groups of patients was analyzed. Group I included 206 patients undergoing mitral valve replacement with porcine xenograft valves. They were placed on a regimen of long-term oral anticoagulation (greater than 8 weeks, mean 6 months). Follow-up was 524.3 patient-years, mean 30.5 months. There were 24 thromboembolic events (4.6% per patient-year), four of which were fatal. Actuarially, 80.7% +/- 4.3% are free of thromboembolism at 8 years. There were 12 instances of major bleeding episodes, for a linearized incidence of 2.5% per patient-year; two were fatal. Group II included 322 patients undergoing mitral valve replacement with a bovine pericardial valve. They were placed on a program of short-term anticoagulation (6 weeks only). Follow-up was 1,106 patient-years, mean 46.4 months. There were four thromboembolic episodes (none fatal), an incidence of 0.36% per patient-year. Seven bleeding episodes occurred, 0.63% per patient-year; none was fatal. The difference between the groups reached statistical significance (p less than 0.001). The low risk of thromboembolism with the bovine pericardial valve appears to be due to its superior hydraulic characteristics. Use of this valve allows mitral valve replacement without long-term oral anticoagulation and the associated risk of anticoagulant-related hemorrhage.     

Does preservation of the sub-valvular apparatus during mitral valve replacement affect long-term survival and quality of life? A Microsimulation Study

Background  

Techniques to preserve the sub-valvular apparatus in order to reduce morbidity and mortality following mitral valve replacement have been frequently reported. However, it is uncertain what impact sub-valvular apparatus preservation techniques have on long-term outcomes following mitral valve replacement. This study investigated the effect of sub-valvular apparatus preservation on long-term survival and quality of life following mitral valve replacement.     

Surgical treatment of early acute thrombosis of mechanical mitral prosthesis

Prosthetic valve thrombosis is a rare but life threatening complication of mechanical heart valve prosthesis. A 44-year-old woman diagnosed with rheumatic heart disease with severe mitral valve stenosis, moderate tricuspid valve insufficiency, and atrial fibrillation underwent transseptal mitral valve replacement and tricuspid valvuloplasty in our department. Heparin and warfarin were routinely used postoperatively. Although the international normalized ratio (INR), activated partial thromboplastin time ratio, and platelet count were satisfactory, the patient presented with severe dyspnea suddenly 10 days after discharge; echocardiogram showed that the prosthetic posterior leaflet was immobile. The patient suffered cardiac arrest suddenly during the examination and cardiopulmonary resuscitation was carried out successfully. Emergent surgery was performed, confirming the prosthetic valve thrombosis. The prosthetic valve was replaced with another mechanical prosthesis. The patient recovered smoothly and was discharged 14 days later with atrial fibrillation. During the 12-months follow-up period, her prosthetic valve and heart function were normal with INR around 3.0. This case highlights the need for awareness among clinicians for the possibility of valve thrombosis in the early postoperative period.     

Preexisting mitral valve prosthesis in patients undergoing left ventricular assist device implantation

Experience with patients undergoing left ventricular assist device (LVAD) implantation with preexisting mitral valve prostheses is limited. Patients with mechanical heart valves might have an increased risk of thromboembolism; in patients with biologic valves, there might be a risk of structural deterioration of the leaflets. Out of 597 patients supported with a LVAD system between 2000 and 2009, 18 patients had mitral valve surgery prior to implantation. We excluded all patients below 18 years of age, those with postcardiotomy failure, and patients who had had mitral valve reconstruction. Only 1% of the studied patient population (n= 6) had mitral valve replacement. The mitral valve implantation has been performed 7.4 ± 9.4 years prior to LVAD insertion. None of the valves (one biologic, five mechanical) were exchanged or explanted. LVAD implantation was done either with left lateral thoracotomy (n= 5) or with midline resternotomy (n= 1). Temporary right ventricular assist device support was necessary in one case (16.6%); 30-day mortality was 16.6% (n= 1). Median support time was 14 ± 15 months. Two patients received heart transplantation after 6 and 26 months on the device; four patients died on mechanical circulatory support after 1, 2, 5, and 40 months. No valve or pump thrombosis or other clinically relevant thromboembolic events were observed. Only a small number of patients (1%) had a preexisting mitral valve prosthesis prior to LVAD implantation. No severe adverse events were observed when the prosthesis was left in place. Attention should be paid to the anticoagulation regime.     

Evaluation of the mitral valve leaflet morphology after mitral valve reconstruction with a concept "coaptation length index"

BACKGROUND: In clinical settings, information on morphology of mitral valve leaflet after mitral valve reconstruction is limited. METHODS: Between January 1996 and June 2000, 36 underwent mitral valve repair for mitral regurgitation (MR). The etiology of mitral insufficiency was prolapse, dilated annulus, and ischemic. Ring annuloplasty was performed in all cases. Mitral valve short-axis dimension (MVd), vertical distance between annular line and closing point (Vd), coaptation length (CL), coaptation length index (CL/MVd) were measured by the two-dimensional transesophageal echocardiography for the present 11 cases. RESULTS: In 11 cases, residual MR, using a scale from 0 to 4, was 0 in 5 patients, 1 in 4 patients, 2 in 2 patients whose etiology of regurgitation was cardiomyopathy. MVd and Vd decreased significantly (38.7 +/- 6.2 to 27.0 +/- 5.6 mm, 10.1 +/- 7.7 to 6.5 +/- 4.6 mm, respectively). CL and CLI increased significantly (6.4 +/- 2.4 to 11.6 +/- 4.6 mm, 0.16 +/- 0.06 to 0.44 +/- 0.21, respectively). Among those index, only CLI have a statistically significant negative correlation with the degree of residual MR. CONCLUSION: The mitral valve ring annuloplasty produce the morphologic change of mitral apparatus, especially the increase of CLI, which may be one of the main factors in regulation of regurgitation.     

Long-term performance of prostheses in mitral valve replacement

The long-term performance of prostheses in mitral valve replacement (MVR) is now available with representatives of current generation prostheses to 15 years. Mechanical prostheses have been implanted for 33 years and bioprostheses for 22 years. The predominant complication of mechanical prostheses is hemorrhage from anticoagulation and reoperation for late structural valve deterioration of bioprostheses. Mitral valve (MV) reconstruction, over MVR, is recommended whenever possible, especially with the advancement of atrial fibrillation ablation techniques. The current indications for MVR are those valvular lesions that are unlikely to be repaired by most surgeons or which long-term results are suboptimal with reconstruction. Reconstruction is more common for degenerative disease, replacement for rheumatic disease and variable for advanced ischemic and infective disease. The recommendations for MVR for mitral stenosis (MS) are moderate to severe MS with advanced functional status and severe pulmonary hypertension when percutaneous balloon valvotomy or mitral reconstruction is not feasible. MVR is recommended in non-ischemic severe mitral regurgitation (MR) and for non-reparable acute symptomatic MR, advanced symptomatic status, systolic dysfunction and/or ventricular dysfunction. The recommendations for MV surgery in ischemic MR are acute post-infarction MR with cardiogenic shock, unstable angina with persistent moderate-severe and severe MR and chronic, dilated ischemic cardiomyopathy with moderate-severe and severe MR.     

Papillary fibroelastoma of the mitral valve associated with rheumatic mitral valve stenosis

With the advent of echocardiography, diagnosis of papillary fibroelastoma in living patients has been made possible, yet papillary fibroelastoma found in the living remains a very rare cardiac tumor. We report a case of papillary fibroelastoma of the mitral valve with rheumatic mitral valve stenosis. A 68-year-old woman was referred to our hospital with a mitral valve tumor and rheumatic mitral valve stenosis. She underwent anticoagulation therapy with Warfarin for 8 years since having a cerebral embolization. Echocardiography revealed a mass attached to the mitral valve, with severe mitral valve stenosis. Electrocardiography demonstrated a chronic atrial fibrillation. Tumor excision with mitral valve replacement and maze procedure were performed. Both the surgical and histological findings depicted papillary fibroelastoma. The postoperative course was uneventful and the patient has remained symptom-free one year after surgery.     

Early and late results of partial plication annuloplasty for congenital mitral insufficiency

BACKGROUND: Partial plication annuloplasty is the main technique for congenital mitral insufficiency because this technique allows the mitral anulus to grow, in contrast to ring annuloplasty. However, this technique is not satisfactory for mitral insufficiency with some anomalies of the mitral valve apparatus. METHODS: Forty-one patients underwent partial plication annuloplasty for mitral regurgitation from July 1979 to December 1998. Mitral regurgitation associated with an atrioventricular defect, an atrioventricular discordance, and a univentricular heart was excluded from this study. RESULTS: There were no early or late deaths. In early results, partial plication annuloplasty was more effective for mitral regurgitation with abnormality of the posterior leaflet (n = 14) or normal leaflet motion (n = 8) than with abnormality of the anterior leaflet and its apparatus (n = 14) or absence of chordae (n = 4). The mean follow-up period was 145.8 months. During the follow-up period, 2 patients underwent mitral valve replacement, and a third patient underwent mitral valve repair with partial plication annuloplasty after the first repair. The main cause of mitral regurgitation of 2 of the 3 patients was absence of chordae. The actuarial freedom from reoperation rate was 94.9% +/- 3.6%, 91.9% +/- 4.7%, and 91.9% +/- 4.7% at 5, 10, and 15 years after the operation, respectively. CONCLUSION: Early and long-term results of partial plication annuloplasty were acceptable for congenital mitral insufficiency with any type of malformation of the mitral valve, and results were excellent with abnormality of the posterior leaflet and its apparatus or normal leaflet motion. However, late results were suboptimal for mitral regurgitation with absence of chordae. Other techniques, such as artificial chorda replacement, should be adapted in these cases.     

Evaluation of the mitral valve leaflet morphology after mitral valve reconstruction with a concept "coaptation length index"

BACKGROUND: In clinical settings, information on morphology of mitral valve leaflet after mitral valve reconstruction is limited. METHODS: Between January 1996 and June 2000, 36 patients underwent mitral valve repair for mitral regurgitation (MR). The etiology of mitral insufficiency was prolapse, dilated annulus, and ischemia. Ring annuloplasty was performed in all cases. Mitral valve short-axis dimension (MVd), vertical distance between annular line and closing point (Vd), coaptation length (CL), and coaptation length index (CLI) were measured by two-dimensional transesophageal echocardiography for the present 11 cases. RESULTS: In 11 cases, residual MR, using a scale from 0 to 4, was 0 in 5 patients, 1 in 4 patients, 2 in 2 patients whose etiology of regurgitation was cardiomyopathy. MVd and Vd decreased significantly (38.7+/- 6.2 to 27.0 +/- 5.6 mm, 10.1 +/- 7.7 to 6.5 +/- 4.6 mm, respectively). CL and CLI increased significantly (6.4 +/- 2.4 to 11.6 +/- 4.6 mm, 0.16 +/- 0.06 to 0.44 +/- 0.21, respectively). Among those indices, only CLI has a statistically significant negative correlation with the degree of residual MR. CONCLUSION: Mitral valve ring annuloplasty produces the morphologic change of the mitral apparatus, especially increase of CLI, which may be one of the main factors in regulation of regurgitation.