Thrombolytic therapy for obstruction of mechanical prosthetic valves

Bioprosthetic mitral valve stenosis secondary to hypereosinophilic syndrome

Herein we present a case of hypereosinophilic syndrome (HES) with recurrent involvement of mitral valve. The patient developed mitral regurgitation secondary to HES. Surgical mitral valve replacement was performed successfully. The prosthetic valve dysfunction occurred 3 years later and echocardiography showed severe mitral valve stenosis. Extensive mural thrombi were discovered on both sides of the stenotic valve with eosinophilic infiltration. The patient underwent a repeated mechanical prosthesis replacement and recovered uneventfully.

Thrombolysis Is an Effective and Safe Therapy in Stuck Mitral Valves With Delayed Presentation as Well as Hemodynamically Unstable Patients: A Single Centre Study

Background

Thrombosis is a complication of prosthetic valves on oral anticoagulants which is associated with significant morbidity and mortality. A re-operation carries a substantial risk, with mortality rate from 10% to 15% in selected series, which may be 2- or 3-folds higher in critically ill patients. This study conducted in a tertiary care cardiology unit aimed to evaluate the effectiveness and safety of thrombolytic therapy in stuck mitral bileaflet heart valves.

Methods

As a prospective observational study, clinical symptoms and fluoroscopy were the mainstay in diagnosis of stuck mitral valve. Gradient across the valve by transthoracic echocardiography was used to monitor the therapy every 6 h. Fall of mean gradient more than 50% was considered as successful thrombolysis. And final results were again checked by fluoroscopy with documentation of improved leaflet movement.

Results

Totally we studied 34 patients. Patients receiving thrombolytic therapy with streptokinase achieved an overall 91.2% freedom from a repeat operation or major complications, a large subcutaneous hematoma occurred in one ( 2.9%), reoperation required in two due to failure of treatment (5.9%), allergic reaction in one (2.9%), one patient developed transient neurologic dysfunction (2.9%) and one patient died during therapy due to refractory cardiogenic shock(2.9%). All patients including those with delayed presentation (> 14 days) and hemodynamically unstable patients had good results similar to those who presented within 14 days and hemodynamically stable. Mortality was higher in unstable patients and reoperation was higher with delayed presentation.

Conclusions

Thrombolysis with streptokinase is highly successful and safe therapy in hemodynamically stable as well as unstable patients, or those with early or delayed presentation with stuck bileaflet mitral valves, especially in centers where round the clock cardiothoracic surgery backup is not available.

Evaluation of Prosthetic Heart Valves by Transesophageal Echocardiography: Problems, Pitfalls, and Timing of Echocardiography

Transesophageal echocardiography (TEE) is especially suitable for examination of prosthetic valves because of the proximity of the esophagus to the heart and absence of interference with lungs and ribs. This article reviews normal and abnormal morphologic characteristics of prosthetic valves such as spontaneous echocontrast, microbubbles, strands, sutures, vegetations or thrombus. Doppler echocardiographic characteristics of normal and pathologic prosthetic valve function and the management of prosthetic valve pathology is discussed. Physicians taking care of patients with prosthetic valves should be familiar with the characteristics of normal and abnormally functioning prosthetic valves.

Fatal Cerebral Hemorrhage Complicating Thromboembolic Stroke in a Patient with Prosthetic Mitral Valve Thrombosis Treated with Thrombolytic Therapy

We report the case of a 66-year-old male with a history of mitral valve replacement with a Sorin tilting-disk prosthesis and a subsequent operation for severe constrictive pericarditis. After 5 years of stable anticoagulant treatment, he suffered an intracerebral hemorrhage that required temporary withdrawal of warfarin. Thrombosis of the prosthesis, presenting as acute heart failure, was then determined. Due to high-operative and hemorrhagic risk, the patient was treated with low-dose thrombolytic therapy administered as two boluses of recombinant tissue plasminogen activator (r-tPA). The patient's hemodynamics improved strikingly. However, a few hours after the second dose, a devastating cerebral hemorrhagic infarction resulted in death. Autopsy showed the primarily ischemic nature of both strokes. The schemes of thrombolytic therapy in prosthetic heart valve thrombosis and the importance of a correct interpretation of pathogenesis of stroke in anticoagulated patients are discussed. Key Words: Heart valve thrombosis— Thrombolysis—Stroke—Warfarin.

Successful fibrinolytic treatment of prosthetic heart valve thrombosis using streptokinase

OBJECTIVES

This study aims to evaluate the clinical outcome of fibrinolytic treatment of prosthetic valve thrombosis (PVT) with 'streptokinase' as a first line treatment for these cases.

METHODS

The study group was 20 consecutive patients (10 females) diagnosed with PVT. The protocol for streptokinase administration was either accelerated (intravenous infusion of 0.5 million IU over 30 minutes followed by 0.15 million IU/h) or conventional (intravenous infusion of 0.25 million IU over 30 minutes followed by 0.15 million IU/h). Success of fibrinolytic therapy was defined as complete restoration of valve function in the presence or absence of complications.

RESULTS

Eighteen patients (90%) had mitral PVT and two (10%) had aortic PVT. Thrombolytic therapy with streptokinase was successful in all but one case, with a total mortality of four cases (20%). In PVT episodes, before streptokinase therapy, the prosthetic valve areas (in all cases, mitral and aortic positions) were 0.82 ± 0.21, 0.83 ± 0.21, and 0.73 ± 0.18 cm²; and the peak and mean transvalvular gradients were 38.7 ± 16.7 and 25.4 ± 8.7, 34.1 ± 8.8 and 23.2 ± 5.4, and 80.0 ± 14.1 and 45.0 ± 7.1 mmHg, respectively. After streptokinase therapy, the prosthetic valve area and peak and mean transvalvular gradients improved significantly (for all cases, mitral and aortic positions: valve area 2.17 ± 0.58, 2.21 ± 0.61, and 1.85 ± 0.07 cm², peak gradient 18.7 ± 11.0, 16.4 ± 7.7, and 39.0 ± 18.4, and mean gradient 9.6 ± 7.1, 8.2 ± 5.3, and 22.0 ± 11.3 mmHg, respectively; paired t-test, P<0.001 for pre- versus post-streptokinase infusion for all variables).

CONCLUSION

Fibrinolytic therapy using streptokinase was an effective therapeutic strategy for the management of PVT and is a reasonable alternative to surgery.

Fibrinolytic therapy for mechanical pulmonary valve thrombosis

Treatment of prosthetic heart valve thrombosis using intravenous thrombolytics, although an acceptable alternative to surgery, is not complication free, and the literature has a dearth of data on the subject. This study analyzed the results of fibrinolytic treatment (FT) among a single-center group of patients with mechanical pulmonary valve thrombosis. Between 2000 and 2013, 23 consecutive patients with 25 episodes of pulmonary valve thrombosis received FT. The diagnosis of mechanical pulmonary valve thrombosis was established by fluoroscopy and echocardiography. Streptokinase (SK) was used in 24 cases and alteplase in 1 case. The FT was continued a second day for 14 patients (58.3%), a third day for 1 patient, and a fourth day for 1 patient. Echocardiography and fluoroscopy were performed every day until improvement of malfunction was achieved. Of the 23 patients, 19 had complete resolution of hemodynamic abnormalities after FT, 1 had partial resolution, and 2 showed no change. No patient had major complications. Five minor complications were detected, namely, fever, nausea, thrombophlebitis, epistaxi, and pain. Seven patients (30%) experienced recurrence of thrombosis, whereas four patients had surgery (biological pulmonary valve replacement) without re-thrombolytic therapy, one patient was treated with Alteplase, one patient received SK, and one patient received intense anticoagulation using heparin and warfarin. Overall, FT had a success rate of 84%. The results indicate that regardless of the time to pulmonary valve replacement and echocardiographic and fluoroscopic findings, FT was effective in most cases of mechanical pulmonary valve thrombosis. The efficacy increased with second-day thrombolytic therapy. Major complications were not common after lytic therapy for mechanical pulmonary valve thrombosis.

Misconceptions, diagnostic challenges and treatment opportunities in bioprosthetic valve thrombosis: lessons from a case series

OBJECTIVES

Bioprosthetic valve thrombosis (BPVT) is a rare but potentially life-threatening complication. Current guidelines favour surgery or thrombolysis as initial treatment. We set forth to characterize timing, diagnostic criteria and treatment strategies in BPVT.

METHODS

A free-text search tool was used to identify patients diagnosed with BPVT at Mayo Clinic between 1997 and 2013. We compared patients treated initially with vitamin K antagonists (VKA group; N = 15) versus surgery/thrombolysis (non-VKA group; N = 17).

RESULTS

Peak incidence of BPVT was 13-24 months after implantation in both groups. VKA and surgery/thrombolysis decreased prosthetic mean gradients to a similar extent (VKA group: 13 ± 5 to 6 ± 2 mmHg in mitral position, 9 ± 3 to 5 ± 1 mmHg in tricuspid position and 39 ± 3 to 24 ± 7 mmHg in aortic/pulmonary position; non-VKA group: 16 ± 12 to 5 ± 1 mmHg in mitral, 10 ± 5 to 4 ± 1 mmHg in tricuspid and 57 ± 9 to 18 ± 6 mmHg in aortic position; P = 0.59 for group effect). NYHA class improved in 11 of 15 patients in the VKA group and 10 of 17 patients in the non-VKA group (P = 0.39). There were no deaths, strokes or recognized embolic events; 1 patient in each group experienced gastrointestinal bleeding requiring transfusion. Index transthoracic echocardiogram formally identified BPVT in a minority of patients.

CONCLUSIONS

BPVT may occur late after surgical implantation. VKA therapy resulted in haemodynamic and clinical improvement with minimal risk, and should be considered the first-line therapy in haemodynamically stable patients. Echocardiographic criteria for improving BPVT diagnosis are proposed.

Management of recurrent mechanical prosthetic tricuspid valve thrombosis in the perioperative period of noncardiac surgery: a case report

Introduction

Mechanical valves in the tricuspid position may be prone to thrombosis with even brief lapses in anticoagulation. The management of patients with a history of recurrent mechanical tricuspid valve thrombosis who require noncardiac surgery is complex.

Case presentation

A 43-year-old Pakistani woman with a mechanical tricuspid valve and a history of multiple episodes of mechanical valve thrombosis presented for noncardiac surgery. After her surgery she was found to have another episode of valve thrombosis and underwent a redo tricuspid valve replacement.

Conclusion

This case brings up the important dilemma that exists when patients with a mechanical tricuspid valve and a history of recurrent valve thrombosis require noncardiac surgery.

Case study and review: treatment of tricuspid prosthetic valve thrombosis

Prosthetic valve thrombosis (PVT) is a severe and life-threatening complication of heart valve replacement. Conventional therapy is surgical thrombectomy or valve replacement. Medical thrombolysis is another emerging option. We report the case of a 57 year old woman with a history of Ebstein anomaly who underwent successful treatment of tricuspid prosthetic valve thrombosis with intra-atrial infusion of very low dose recombinant tissue plasminogen activator (tPA). We review the presentation, etiology, diagnosis, and treatment of tricuspid PVT emphasizing a modified medical option as a safe, minimally invasive alternative to surgical intervention or conventional medical therapy for tricuspid valve thrombosis.

Prosthetic heart valve thrombosis, anticoagulation and pregnancy: a case report and review of literature

In pregnant patients with a prosthetic heart valve (PHV), anticoagulation with warfarin is associated with embryopathy, foetal loss early in pregnancy and maternal bleeding complications in the delivery period. The optimal anticoagulation strategy in the pre-pregnancy period and during pregnancy itself is controversial and a matter of debate. We describe a patient with PHV in the pre-pregnancy period and in a subsequent pregnancy. The optimal anticoagulation treatment strategy in women in their reproductive years with mechanical valve thrombosis is discussed. (Neth Heart J 2007;15:306-9).

Successful fibrinolytic treatment in a pregnant woman with acute mitral prosthetic valve thrombosis

Pregnant patients with mechanical prosthetic heart valves pose a great problem for medical management. The problem is even greater in a pregnant woman with mechanical valve thrombosis. This article describes a pregnant woman with prosthetic mitral valve thrombosis who had a successful fibrinolytic treatment.

Transesophageal echocardiography improves risk assessment of thrombolysis of prosthetic valve thrombosis: results of the international PRO-TEE registry

OBJECTIVES

The goal of this study was to evaluate whether quantitation of thrombus burden with transesophageal echocardiography (TEE) can help risk-stratify patients undergoing thrombolysis of prosthetic valve thrombosis (PVT).

BACKGROUND

Thrombolytic therapy of PVT has an unpredictable risk of embolization and complications.

METHODS

An international registry of patients with suspected PVT undergoing two-dimensional/Doppler and TEE before thrombolysis was established. All TEE studies were reviewed and quantitated by a single observer blinded to all data.

RESULTS

From 1985 to 2001, 107 patients (71 females; age 24 to 86 years) from 14 centers (6 in the U.S.) were identified. The majority of cases involved the mitral valve (79 mitral, 13 aortic, and 15 tricuspid). Hemodynamic success rate was achieved in 85% and was similar across valves. Overall complications were observed in 17.8%, and death in 5.6%. Predictors of complications were: New York Heart Association (NYHA) functional class, presence of shock, sinus tachycardia, hypotension, previous history of stroke, thrombus extension beyond the valve ring, and thrombus area. Multivariate analysis demonstrated that two variables were independent predictors of complications: thrombus area by TEE (odds ratio [OR] 2.41 per 1 cm2 increment, 95% confidence interval [CI] 1.12 to 5.19) and prior history of stroke (OR 4.55, 95% CI 1.35 to 15.38). A thrombus area <0.8 cm2 identified patients at lower risk for complications from thrombolysis, irrespective of NYHA functional class.

CONCLUSIONS

In PVT, the thrombus size imaged with TEE is a significant independent predictor of outcome. Transesophageal echocardiography can identify low-risk groups for thrombolysis irrespective of symptom severity and is therefore recommended in the management of prosthetic valve thrombosis.

Successful thrombolysis of a partially obstructed bileaflet prosthetic heart valve in the mitral position

We describe the case of a woman who presented with dyspnea of abrupt onset and who had recently undergone replacement of the mitral valve with a bileaflet mechanical prosthesis. Transthoracic echocardiographic examination with spectral Doppler recording of transvalvular blood flow revealed a velocity spectrum consistent with obstruction. Transesophageal echocardiography demonstrated partial obstruction of the prosthetic valve due to immobilization of 1 hemidisc in the closed position. This immobilization was apparently caused by a small mass whose appearance was consistent with that of a thrombus. The patient was successfully treated by intravenous administration of a thrombolytic agent. This case demonstrates the value of transesophageal echocardiography in the selection of candidates for thrombolytic treatment in cases of thrombosis of a left-sided valve prosthesis.

Thrombotic occlusion of Bjork-Shiley prosthetic aortic valve

Thrombotic occlusion of a prosthetic Bjork-Shiley valve is a potentially fatal complication. We present the case of a male, 62 years of age, diagnosed with thrombotic occlusion of prosthetic Bjork-Shiley aortic valve approximately 17 years post implantation. A brief review of the literature focusing on potential risk factors associated with the development of this condition and currently available diagnostic modalities used for evaluation and treatment are presented.

Fibrinolysis of mechanical prosthetic valve thrombosis: a single-center study of 127 cases

OBJECTIVES

This study was designed to analyze the results of fibrinolytic treatment (FT) in a large single-center group of patients with prosthetic heart valve thrombosis (PHVT).

BACKGROUND

Fibrinolytic treatment of PHVT represents an alternative to surgery, but is still controversial because of the risk of embolism.

METHODS

A total of 110 consecutive patients presenting with 127 instances of PHVT received FT between 1978 and 2001. The diagnosis of PHVT was established mainly by fluoroscopy and/or echocardiography. The first fibrinolytic agent used was streptokinase (SK) in 49 cases, urokinase (UK) in 41 cases, and recombinant tissue-type plasminogen activator (rtPA) in 37 cases. A second FT was consecutively infused in 38 patients (30%) and a third FT in 11 others. The efficacy of FT was assessed from hemodynamic parameters derived from echographic examinations as well as on clinical grounds.

RESULTS

Complete resolution of hemodynamic abnormalities was seen in 90/127 patients, partial resolution in 22/127 patients, and no change in 15/127 patients after one or more consecutive fibrinolytic regimens. When SK or rtPA were used as the first fibrinolytic agent, they appeared significantly superior to UK in terms of valve reopening. Fifteen patients died. Severe hemorrhagic complications were observed in six patients. Nineteen documented embolic events occurred during FT. Finally, PHVT recurred in 24 patients, 17 of whom were retreated with lytic agents.

CONCLUSIONS

These results indicate that FT is effective in most cases of PHVT, regardless of prosthesis or site involved. However, embolism, hemorrhage, and death were not uncommon after lytic therapy of left-sided PHVT, limiting its application to patients at high risk with alternative treatment.

Successful thrombolysis of st. Jude medical aortic prosthesis with tissue-type plasminogen activator in a pregnant woman: a case report

Mechanical valve thrombosis is a life-threatening event. Pregnancy is associated with a hypercoagulable state that further emphasizes the importance of adequate anticoagulation. This is associated with a therapeutic dilemma. Continued anticoagulation with warfarin throughout the first trimester can result in fetopathic effects, while replacement of warfarin by heparin between 6 and 12 weeks of gestation does not completely prevent the risk of valve thrombosis. There are a small number of reported cases of pregnant women with prosthetic heart valve thrombosis under low molecular weight heparin and consecutive lytic therapy. The authors report a 33-year-old pregnant woman with a St. Jude Medical aortic prosthesis, anticoagulated with a therapeutic dosage of low molecular weight heparin from 6 weeks of gestation, who developed prosthetic heart valve thrombosis at 17 weeks of gestation. A thrombolysis with recombinant tissue-type plasminogen activator (50 mg for 2 hours) was performed. Under thrombolysis, ST-segment elevation in leads II, III, aVF, V5, and V6 developed electrocardiographically with a maximal creatine kinase (CK) of 349 U/L (CK-MB isoenzyme of 48 U/L). Echocardiography revealed normal function of the St. Jude Medical aortic prosthesis 2 hours after thrombolysis and normal wall motions. Short-course thrombolytic therapy appears to be an effective alternative to surgical intervention for the treatment of thrombotic dysfunction of valve prostheses in pregnancy.

[Prosthetic valve thrombosis: which is the most appropriate initial therapy?]

INTRODUCTION AND OBJECTIVES

This study aims to investigate what is the best initial therapy for patients with obstructive prosthetic valve thrombosis.

METHODS

Data from 47 patients diagnosed with prosthetic valve thrombosis in two tertiary hospitals during an 8-years period were analyzed.

RESULTS

The involved prostheses were in mitral position in 34 cases (2 biological valves), in aortic position in 12, and in double mitral and aortic position in one. The thrombosis was not obstructive in 12 patients. In the remaining 35 patients, the prosthetic obstruction was treated by heparin (n = 2), thrombolysis (n = 19), or direct surgery (n = 14). There was no mortality in the thrombolytic group, although 6 patients needed surgery before discharge because of an abnormal prosthetic residual gradient (n = 5) or a persisting abnormal disc valve motion (n = 1). Five out of 14 patients of direct surgery died, 2 before the planned operation could be performed. Thus, mortality rate, in an intention to treat analysis, was very favourable to thrombolytic therapy (p = 0.008); and this, despite the higher index of clinical severity (on a scale from 0 to 4) was superior in this group of thrombolyzed patients: 3.3 0.6 vs. 2.1 0.9 in those who underwent surgery; p < 0.0001.

CONCLUSIONS

In terms of mortality rate, thrombolysis is a better alternative than direct surgery to fight against obstructive prosthetic valve thrombosis. Even if the result is suboptimal, it allows the performance of surgery in better clinical conditions and, thus, with minor risk.

Prosthetic valve thrombosis and thrombolysis: a case report and review of the literature

Prosthetic valve thrombosis is a rare but serious complication of implanted mechanical valves. Thrombolysis has emerged as an alternative to surgical therapy in the management of these patients. The indications for such therapy and appropriate patient selection are evolving. Our report describes management of a patient we encountered with this complication and reviews the current status of thrombolysis in such patients.

Reoperation for prosthetic aortic valve obstruction in the era of echocardiography: trends in diagnostic testing and comparison with surgical findings

OBJECTIVES

We sought to: 1) identify trends in the diagnostic testing of patients with prosthetic aortic valve (AVR) obstruction who undergo reoperation and 2) compare diagnostic test results with pathologic findings at surgery.

BACKGROUND

It is unclear whether Doppler transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) have reduced hemodynamic catheterization rates.

METHODS

We reviewed 92 consecutive cases ofAVR reoperation at a single center from 1989 to 1998, comparing 49 cases of mechanical AVR obstruction (group A) to 43 cases of bioprosthetic obstruction (group B). Preoperative Doppler TTE was performed in all cases.

RESULTS

In group A cases, there was a marginally significant trend towards lower catheterization rates for the Gorlin AVR area, from 36% in 1989 to 1990 to 10% in 1997 to 1998 (p = 0.07), but diagnostic TEE utilization (47% of cases) did not vary. The cause of mechanical AVR obstruction was pannus in 26 cases (53%), mismatch (P-PM) in 19 (39%) and thrombosis in 4 (8%). The mechanism (pannus/thrombus vs. mismatch) was identified in 10% by TTE and 49% by TEE (p < 0.001). In group B cases, hemodynamic catheterization rates (21%) and diagnostic TEE utilization (21%) did not vary with time. Obstruction was caused by structural degeneration in 37 cases (86%), thrombosis in 3 (7%), mismatch in 2 (5%) and pannus in 1 (2%). The mechanism was correctly identified in 63% by TTE and in 81% by TEE (p = 0.18).

CONCLUSIONS

Doppler TTE is the primary means to diagnose AVR obstruction; hemodynamic catheterization is not routinely needed. In unselected patients with mechanical AVR obstruction, TEE differentiation of pannus or thrombus from mismatch is challenging.

Prediction of thrombus-related mechanical prosthetic valve dysfunction using transesophageal echocardiography

Identification of thrombus-related mechanical prosthetic valve dysfunction (MPVD) has important therapeutic implications. We sought to develop an algorithm, combining clinical and echocardiographic parameters, for prediction of thrombus-related MPVD in a series of 53 patients (24 men, age 52 +/- 16 years) who had intraoperative diagnosis of thrombus or pannus from 1992 to 1997. Clinical and echocardiographic parameters were analyzed to identify predictors of thrombus and pannus. Prevalence of thrombus and diagnostic yields relative to the number of predictors were determined. There were 22 patients with thrombus, 19 patients with pannus, and 12 patients with both. Forty-two of 53 masses were visualized using transesophageal echocardiography (TEE), including 29 of 34 thrombi or both thrombi and panni and 13 of 19 isolated panni. Predictors of thrombus or mixed presentation include mobile mass (p = 0.009), attachment to occluder (p = 0.02), elevated gradients (p = 0.04), and an international normalized ratio of < or = 2.5 (p = 0.03). All 34 patients with thrombus or mixed presentation had > or = 1 predictor. The prevalence of thrombus in the presence of < or = 1, 2, and > or = 3 predictors is 14%, 69%, and 91%, respectively. Thus, TEE is sensitive in the identification of abnormal mass in the setting of MPVD. An algorithm based on clinical and transesophageal echocardiographic predictors may be useful to estimate the likelihood of thrombus in the setting of MPVD. In the presence of > or = 3 predictors, the probability of thrombus is high.

Thrombolysis is an effective and safe therapy in stuck bileaflet mitral valves in the absence of high-risk thrombi

OBJECTIVES

We sought to evaluate the effectiveness and safety of thrombolytic therapy in stuck mitral bileaflet heart valves in the absence of high-risk thrombi.

BACKGROUND

Current recommendations for the thrombolytic treatment of stuck prosthetic mitral valves are partially based on older valve models and inclusion of patients in whom high-risk thrombi were either ignored or not sought for. The feasibility and safety of thrombolysis in bileaflet models may be affected by the predilection of thrombi to catch the leaflet hinge.

METHODS

We studied 12 consecutive patients (men/women = 5/7, age 58.8 +/- 14.9 years) who experienced one or more episodes of stuck bileaflet mitral valve over a 33-month period and received thrombolytic therapy with streptokinase, urokinase or tissue-type plasminogen activator. Transesophageal echocardiography was performed in all patients. Patients with mobile or large (>5 mm) thrombi were excluded. Functional class at initial episode was I-II in 4 patients (33.3%) and III-IV in 8 patients (66.6%).

RESULTS

Patients receiving thrombolytic therapy achieved an overall 83.3% freedom from a repeat operation or major complications (95% confidence interval 51.6-97.9%). Minor bleeding occurred in three patients (25%) and allergic reaction in one (8.3%). Transient vague neurologic complaints, without subjective findings, occurred in four patients (33.3%). Three patients had one or more relapses within 5.2 +/- 3.1 months from the previous episode, and readministration of thrombolytics was successful.

CONCLUSIONS

In clinically stable patients with stuck bileaflet mitral valves and no high-risk thrombi, thrombolysis is highly successful and safe, both in the primary episode and in recurrence. The best thrombolytic regimen is yet to be established.

Intravenous thrombolytic treatment of mechanical prosthetic valve thrombosis: a study using serial transesophageal echocardiography

OBJECTIVE

We analyzed the results of intravenous thrombolytic treatment under transesophageal echocardiographic (TEE) guidance in prosthetic valve thrombosis.

BACKGROUND

Thrombotic occlusion of prosthetic valves continues to be an uncommon but serious complication. Intravenous thrombolytic treatment has been proposed as an alternative to surgical intervention.

METHODS

In a four-year period, 32 symptomatic patients with prosthetic valve related thrombosis underwent 54 thrombolytic treatment sessions for the treatment of 36 distinct episodes. All patients had low international normalized ratio values at the presentation. Transesophageal echocardiography was performed at baseline and repeated after each thrombolytic treatment session (total 98 TEE examinations). Streptokinase was used as the initial agent with a repeat dose given within 24 h when necessary. Recurrent thrombosis was treated either with tissue plasminogen activator or urokinase.

RESULTS

The initial success after first dose was only 53% (17/32) but increased up to 88% (28/32) after repeated thrombolytic sessions upon documentation of suboptimal results on TEE examination (p < 0.01). In addition, four asymptomatic patients with large thrombi were also successfully treated with single infusion. The TEE characteristics of thrombus correlated with clinical presentation and response to lytics. Success was achieved with single lytic infusion in 40% of the obstructive thrombi as compared with 75% of the nonobstructive ones (p < 0.05). The success rates of lytic treatment were similar for mitral versus aortic valves, and for tilting disk versus bileaflet valves. Rapid (3 h) and slow (15 to 24 h) infusion of streptokinase resulted in similar success rates. However, major complications (three patients) occurred only in the rapid infusion group.

CONCLUSION

In patients with prosthetic valve thrombosis, intravenous slow infusion thrombolysis given in discrete, successive sessions guided by serial TEE and transthoracic echocardiography can be achieved with a low risk of complications and a high rate of success.

Thrombosis of bileaflet tricuspid valve prosthesis: clinical spectrum and the role of nonsurgical treatment

BACKGROUND

Thrombosis of a mechanical tricuspid valve prosthesis is a potentially hazardous event. This study aimed to explore the incidence and the clinical presentation of tricuspid valve thrombosis occurring in bileaflet valves and to evaluate the diagnostic and the therapeutic approach.

METHODS AND RESULTS

Tricuspid valve thrombosis was sought in 22 late survivors with the CarboMedics valve in a follow-up period of 36.0 +/- 20.8 months. Limited leaflet motion and/or a visible thrombus were considered diagnostic of valve thrombosis. Eight episodes of tricuspid valve thrombosis were diagnosed among 5 patients (12.1 episodes per 100 patient-years). Anticoagulation was inadequate in 3 patients and fair in 2. Florid right heart failure occurred in 3 episodes. Common physical findings included increased jugular venous pulse (5 patients), diastolic tricuspid murmur (4 patients), and peripheral edema (4 patients). The diagnosis was suspected in all clinically and by transthoracic echocardiography and confirmed by fluoroscopy and/or transesophageal echocardiography. In 4 patients, both leaflets were involved. No thrombi were visualized. Three patients received thrombolytic therapy in 4 episodes (complete success in 3, partial success in 1) without hemorrhagic or embolic complications. One patient responded to aggressive anticoagulant therapy. One patient required an emergent repeat surgery. In 1 patient, valve thrombosis recurred thrice.

CONCLUSIONS

In patients with fair or poor anticoagulation, a bileaflet valve in the tricuspid position is associated with a high incidence of valve thrombosis. Hinge entrapment requires only a small amount of thrombotic material. Valve thrombosis may be asymptomatic. Involvement of both leaflets is usually required to produce symptoms. A nonsurgical approach (thrombolysis or intensified anticoagulation) is usually successful. Patients should be instructed about heralding signs of valve thrombosis.

Mechanical Prosthetic Valve Thrombosis: Case Report and Review of the Literature

Mechanical prosthetic valve thrombosis is a life-threatening complication necessitating immediate intervention. The presenting signs and symptoms of this illness are somewhat variable, but physical examination and transesophageal echocardiography enable rapid diagnosis. To avoid catastrophic complications, valve replacement or debridement, or thrombolysis in the correct setting, must be performed without delay. It is not entirely clear which therapy is superior. For any given patient, the risks of thrombolytic therapy, including bleeding, systemic embolism, and failure to restore valvular function, must be weighed against the risks of surgical intervention. Once the decision is made to operate, the choice of valve replacement versus debridement is one best made intraoperatively, upon visual inspection of the valve apparatus. Despite aggressive therapy, morbidity and mortality from prosthetic valve thrombosis and its treatment are not trivial. Fortunately, with current prosthetic devices and aggressive prophylactic anticoagulation, the incidence of prosthetic valve thrombosis remains low. Antiplatelet therapy may offer additional benefit to patients being prophylaxed with warfarin. This report details the case of a woman with aortic and mitral prosthetic valves who presented with heart failure and evidence of severe aortic prosthetic dysfunction after a period of suboptimal anticoagulation. She successfully underwent debridement of the mitral prosthesis and replacement of the aortic valve. The relevant literature is reviewed.

Differentiating thrombus from pannus formation in obstructed mechanical prosthetic valves: an evaluation of clinical, transthoracic and transesophageal echocardiographic parameters

OBJECTIVES

We sought to determine the clinical and echocardiographic parameters that differentiate thrombus from pannus formation as the etiology of obstructed mechanical prosthetic valves.

BACKGROUND

Distinction of thrombus from pannus on obstructed prosthetic valves is essential because thrombolytic therapy has emerged as an alternative to reoperation.

METHODS

We analyzed clinical, transthoracic and transesophageal echocardiography (TEE) data in 23 patients presenting with 24 obstructed prosthetic valves and compared the findings to pathology at surgery.

RESULTS

Fourteen valves had thrombus and 10 had pannus formation. Patients with thrombus had a shorter duration from time of valve insertion to malfunction, shorter duration of symptoms, but similar New York Heart Association functional class at the time of operation. Patients with thrombus had a lower rate of adequate anticoagulation (21% vs. 89%; p=0.0028). Pannus formation was more common in the aortic position (70% vs. 21%; p=0.035). Abnormal prosthetic valve motion was detected by TEE in all cases with thrombus formation but in 60% with pannus (p=0.0198). Thrombi were larger than pannuses (total length 2.8+/-2.47 cm vs. 1.17+/-0.43 cm; p=0.038). This was mostly due to extension of thrombi into the left atrium in prosthetic mitral valves. Thrombi appeared as a soft mass on the valve in 92% of cases, whereas 29% of pannuses had a soft echo density (p= 0.007). Ultrasound video intensity ratio, derived as the videointensity of the mass to that of the prosthetic valve, was lower in the thrombus group (0.46+/-0.14 vs. 0.71+/-0.17, p=0.006). A videointensity ratio of <0.70 had a positive predictive value of 87% and a negative predictive value of 89% for thrombus. Duration from onset of symptoms to reoperation of <1 month separated thrombus from pannus formation. The best objective clinical parameter for prediction of thrombus was inadequate anticoagulation, whereas the best TEE parameters were qualitative and quantitative ultrasound intensity of the mass. The presence of either inadequate anticoagulation or a soft mass by TEE improved the predictive power of either parameter alone and was similar to that of ultrasound videointensity ratio.

CONCLUSIONS

Duration of symptoms, anticoagulation status and qualitative and quantitative ultrasound intensity of the mass obstructing a mechanical prosthetic valve can help differentiate pannus formation from thrombus and may therefore be of value in refining the selection of patients for thrombolytic therapy of prosthetic valve obstruction.

Evaluation of prosthetic valve function and associated complications

Significant advances in imaging modalities have occurred to evaluate prosthetic valve function and associated complications. These developments involve predominantly the introduction of Doppler technology for the non-invasive determination of gradients and valve areas and TEE for an improved assessment of valve structure, function, and associated complications. The current role of cinefluoroscopy is mostly to complement TEE in the evaluation of motion of mechanical prosthetic valves in the aortic position. Cardiac catheterization is now rarely needed to assess valve function. Diagnosis of prosthetic valve obstruction can be performed in the majority of cases with transthoracic Doppler echocardiography. Differentiation of valve obstruction from normal valve function in small valves with high flow conditions, however, may be difficult. Because of this and the variability in normal valves among different prostheses, knowledge of the type and size of the implanted valve is essential. Patients and ultrasound laboratories are encouraged to seek and provide this information on a routine basis. Although transthoracic echocardiography is the main diagnostic modality for the serial evaluation of prosthetic valve function, it is important to recognize its limitations in assessing prosthetic mitral regurgitation and evaluating structural abnormalities of prosthetic valves. These are the situations in which TEE has the most impact. A summary of general indications of TEE in prosthetic valves is provided in Table 6. Finally, a baseline transthoracic Doppler study is essential in the overall follow-up and serial evaluation of valve function. For future comparisons, the best indices of valve functions are those obtained for patients as their own control, from a baseline Doppler echocardiographic study performed early after the operation.

Thrombosis of a mechanical tricuspid valve prosthesis and of the left subclavian vein: successful therapy with thrombolysis

A patient with thrombosis of a mechanical prosthetic valve in the tricuspid position, simultaneous extensive left subclavian vein thrombotic occlusion, and pulmonary embolism is successfully treated with a urokinase infusion delivered using catheter-based techniques.