Thrombo-embolic and bleeding complications in patients with mechanical valve replacements--a prospective observational study.

BACKGROUND AND OBJECTIVES: Long-term anticoagulation therapy is essential to prevent thrombo-embolic events in patients with mechanical valve replacements. In order to offer indigent patients mechanical heart valve replacement surgery, dedicated anticoagulation clinics are necessary for follow-up. This study assessed the safety and efficacy of lifelong oral anticoagulation therapy in Johannesburg General Hospital mechanical heart valve replacement recipients. The incidence of bleeding and thrombo-embolic complications was documented in three groups of patients with mechanical valve replacements. The groups included patients with aortic valve replacements (AVRs), mitral valve replacements (MVRs) and double (aortic and mitral) valve replacements (DVRs). MATERIALS AND METHODS: A prospective observational study was conducted over a 4-month period. Data on 306 patients attending the Johannesburg General Hospital anticoagulation clinic between 2000 and 2005 were analysed. Of the total patients selected, 205 were assigned to the mechanical valve replacement group (which included 63 patients with AVRs, 93 with MVRs and 49 with DVRs); a control group of 101 nonmechanical valve replacement patients were also included. At each visit the level of anticoagulation was assessed from the international normalised ratio (INR) values, and the presence of bleeding and/or thrombo-embolic complications was documented. RESULTS: There were a total of 51 bleeding and thrombo-embolic complications in the study population. Patients with DVRs had a higher proportion of combined complications (30.61%) than patients with single valve replacements (14.29% in the AVR group and 18.05% in the MVR group) and patients in the control group (12.87%). There were 38 bleeding complications, 30 minor and 8 major. Twelve thrombo-embolic events were documented. Individually, there was no significant difference in thrombo-embolic and bleeding complications between the subgroups. Eighty-two per cent of patients in the mechanical valve replacement group were within the therapeutic range for anticoagulant control (INR 2.5-3.5) v. 54% in the control group (INR 2.0-3.0). Anticoagulant control was of a high quality and was not a contributing factor to the incidence of bleeding and/ or thrombo-embolic complications. CONCLUSION: The finding of a low incidence of bleeding and thrombo-embolic complications in patients with mechanical valve replacements supports the continued placement of mechanical valves in our setting and use of oral anticoagulation therapy at an INR of 2.5-3.5. However the increased risk of both bleeding and thrombo-embolic complications in the DVR group is cause for great concern and warrants further investigation.     

Early bioprosthetic mitral valve "pseudostenosis" after complete preservation of the native mitral apparatus

An advantage of bioprosthetic mitral valve replacement in patients with normal sinus rhythm is avoidance of the need for long-term anticoagulation. Bioprosthetic valve thrombosis is a rare complication, supporting this approach. This case report represents an example of porcine mitral valve stenosis, likely secondary to thrombosis, in which all of the native mitral valve apparatus was left intact. This was successfully treated with standard anticoagulation therapy. This complication should be considered in patients in whom retention of the mitral valve apparatus has been performed. Such patients may benefit from long-term anticoagulation treatment to obviate this event.     

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.     

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.     

Early degeneration of a bioprosthetic mitral valve complicated by a large left atrial thrombus

The authors report the case of a patient with symptomatic early bioprosthetic mitral valve deterioration in the setting of calcium supplementation. This was further complicated by a large left atrial thrombus despite supratherapeutic anticoagulation and a previously oversewn left atrial appendage. As mechanical valves are less predisposed to calcification in comparison with bioprosthetic implants, the patient underwent a mechanical mitral valve replacement in addition to a left atrial thrombectomy.     

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.     

三尖瓣置换术及抗凝治疗70例临床分析

目的 探讨三尖瓣置换术(TVR)的手术指征、瓣膜选择及术后抗凝治疗方法.方法 1998年5月至2008年1月,共有70例患者接受TVR,其中风湿性心脏病患者59例.手术包括:二尖瓣置换术(MVR)+TVR 37例,MVR+主动脉瓣置换术(AVR)+TVR 18例,TVR 13例,TVR+AVR 2例.全部患者自术后2 d开始采用华法林进行抗凝治疗.结果 术后3例患者因低心排血量死亡,死亡率4.3%.1例发生Ⅲ度房窒传导阻滞,1例发生急性肾功能衰竭,并发症率7.1%.随访59例,随访率88.1%,平均随访(3.6±5.2)年,共243.5人年.1例患者于术后3个月死亡;远期死亡率0.4%人年.5例患者出现一般性出血,出血率2.1%人年.1例发生脑梗死,1例因三尖瓣血栓形成再手术,栓塞率0.8%人年.门诊随访INR均值1.87±0.68.患者术后心功能(NYHA分级)Ⅰ～Ⅱ级52例,Ⅲ级7例.结论 风湿性心脏病三尖瓣病变严重者应行TVR;双叶机械瓣膜应用于TVR效果满意;TVR术后抗凝治疗强度尚有待探讨.     

Better anticoagulation control improves survival after valve replacement

OBJECTIVE: We sought to assess the effect of anticoagulation control on long-term survival after valve replacement with the Medtronic Hall valve (Medtronic, Inc, Minneapolis, Minn). METHODS: Prospective follow-up data, including 82,297 international normalized ratios, were collected for 1476 patients undergoing single valve replacement with the Medtronic Hall valve between 1979 and 1994, with follow-up to the end of 1998. After excluding 204 patients who either died within 30 days or had fewer than 10 international normalized ratios recorded beyond 30 days, there were 10,203 patient years of follow-up for analysis. Anticoagulation variability was measured as the percentage of international normalized ratios outside a target range of 2.0 to 4.0 for each patient. RESULTS: Linearized rates for late death rose progressively with increasing deciles of anticoagulation variability for both aortic and mitral valve replacement (2.7% and 3.3% per year, respectively, in deciles 1 and 2 up to 9.5% and 14.6% per year, respectively, in deciles 6-10; P <.001). Survival at 15 years after aortic valve replacement was 59% for low anticoagulation variability (deciles 1 and 2), 55% for intermediate anticoagulation variability (decile 3), and 28% for high anticoagulation variability (deciles 4-10); survivals at 15 years after mitral valve replacement were 56%, 42%, and 24%, respectively (P <.001 between low-intermediate anticoagulation variability and high anticoagulation variability for both aortic and mitral valve replacement). On multivariate analysis, significant predictors of reduced survival were anticoagulation variability per 20% increase (hazard ratio, 1.8), diabetes (hazard ratio, 1.6), decade of age (hazard ratio, 1.6), concomitant coronary artery bypass grafting (hazard ratio, 1.5), male sex (hazard ratio, 1.4), hypertension (hazard ratio, 1.4), New York Heart Association class III or IV (hazard ratio, 1.3), and non-sinus rhythm (hazard ratio, 1.2). Patients with low anticoagulation variability who were in sinus rhythm and did not have diabetes, coronary bypass grafting, or hypertension had survivals equal to those of the age- and sex-matched general population at 15 years. The incidence of valve-related deaths was significantly higher with high anticoagulation variability compared with the incidence with low-intermediate anticoagulation variability for both aortic (1.4% vs 0.5% per year, P <.001) and mitral valve replacement (1.5% vs 0.5% per year, P <.001). By means of univariate analysis, high anticoagulation variability was significantly associated with New York Heart Association class III or IV at 5 years postoperatively (P <.001) and with age of greater than 60 years at the time of the operation (P =.002). CONCLUSIONS: High anticoagulation variability is the most important independent predictor of reduced survival after valve replacement with a mechanical valve. Better anticoagulation control should improve survival.     

Anticoagulation for prosthetic heart valves during pregnancy: is low-molecular-weight heparin an alternative?

We report on the treatment failure of low molecular weight heparin (LMWH) for anticoagulation in a pregnant woman that underwent artificial mitral valve replacement 10 years prior to her pregnancy. Until she became pregnant warfarin was administered for anticoagulation, but due to the often mentioned increased risk for warfarin-induced maternal and fetal complications, at gestational week 5 the anticoagulation regimen was switched to subcutaneous application of low molecular weight heparin. At gestational week 24 our patient developed acute life-threatening pulmonary edema and hemodynamic instability due to acute mitral valve thrombosis and underwent emergency valve re-replacement with a biological porcine valve. She recovered uneventfully and gave birth to a healthy child at gestational week 35. In addition to our case presentation we review the sparse evidence in the literature regarding anticoagulation in pregnant women with mechanical heart valves and discuss the rational of different anticoagulation regimens with regards to maternal and fetal outcome. Special consideration is directed towards LMWH administration as an alternative to oral anticoagulation during pregnancy in women with mechanical heart valves.     

Mitralklappenrekonstruktion bei degenerativer Mitralinsuffizienz

Over the years mitral valve repair has become the therapy of choice for the surgical treatment of degenerative mitral valve disease. Mitral valve repair avoids the drawbacks of mitral valve replacement: mandatory life-long anticoagulation in case of mechanical prostheses, and limited durability associated with bioprostheses. Furthermore, mitral valve repair respects the integrity of the valvular apparatus, and consequently preserves the systolic function of the left ventricle. Alain Carpentier developed and conceptualized the functional approach for mitral valve reconstruction aimed at restoring the coaptation surface, the essence of the ??French Correction??. Major milestones have played an important role in the development and refinement of mitral valve repair. Transesophageal echocardiography enabled better visualization of the dynamics of the mitral valve and has established itself as an essential quality control tool. The minimally invasive approach to the mitral valve adopted in the late 1990??s represents another step in the development of mitral valve repair. Aimed at reducing surgical trauma as far as possible, it offers the same results as conventional median sternotomy. Surgery for mitral valve insufficiency has been a very dynamic field over the past 40?years, aiming at repairing most of the degenerative valves and at the same time minimizing surgical trauma.     

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.     

Long-term results of mechanical valves in aortic position and biological valves in mitral and tricuspid positions

The long-term results of patients undergoing aortic valve replacement (AVR) with a mechanical valve (AM), mitral valve replacement with a biological valve (MB), and tricuspid valve replacement (TVR) with a biological valve (TB) operated upon from 1977 to 1988 were retrospectively analysed. A total of 899 patients received 1117 valves (381 AM, 633 TB, 103 TB) with a follow-up 3778 patient-years and 4582 valve-years. A significant incidence of thromboembolism, hemorrhage, and endocarditis was not found among AVR, MVR, TVR, or multiple valve replacement. We found a significantly decreased incidence of survival rate in multiple valve replacement compared with AVR or MVR, and a significantly increased incidence of reoperation in MB compared with AM and TB. We use AM and TB in any adult patients as a first choice. However, we prefer a mechanical valve in the mitral position except in patients over 65 years old, who have a short life expectancy, in whom anticoagulation is thought to be difficult, and who desire a biological valve.     

A case of mitral valve replacement with autologous pulmonic valve in congenital mitral stenosis

A one-year-old infant with congenital mitral stenosis and pulmonary hypertension underwent by mitral valve replacement with his pulmonic valve autograft and pulmonary tract reconstruction with heterogeneous pericardial conduit. His postoperative hemodynamics data showed that left atrial pressure decreased and pulmonary hypertension continued. Echocardiography showed that the implanted autograft functioned properly. On the seventh postoperative day, he died of pulmonary hypertension. In case with congenital mitral stenosis with the small mitral annulus and the small left ventricular cavity, it is difficult to perform mitral valve replacement by commercially available mechanical or tissue valves. Because these valves are not suitable for the small mitral annulus. The mitral valve replacement with pulmonic valve autograft is recommended in such a case with the congenital mitral stenosis.     

Supravalvular mitral remnant: The other side of the… valve

We report a challenging clinical case of an atypical supravalvular mitral remnant in recent mitral and aortic valve replacement with mechanical valve prostheses, associated with postoperative recurrent inflammatory episodes overlapped with difficult anticoagulation. Negative myocardial scintigraphy was associated with persistence of negative blood cultures. Serial echocardiographic evaluation was performed before and after antimicrobial treatment, and at 3 months follow-up a transesophageal echocardiography showed the persistence of the mass. Diagnostic suspect was finally confirmed.     

Acute mechanical valve thrombosis of the St. Jude medical prosthesis

From 1986 to 1996, 2585 patients underwent valve replacement with the St. Jude medical prosthesis. Sixty experienced mechanical valve thrombosis. Seventeen of 60 patients (28.3%) had isolated aortic valve replacements, 33 had isolated mitral valve replacements (55%), and 10 had double valve replacements (16.7%) (aortic and mitral valve replacement). All patients who underwent reoperation for mechanical valve thrombosis were functional Class III or IV. Against medical advice, systemic anticoagulation with warfarin sodium had been discontinued or used only intermittently. Thus, anticoagulant activity was not adequate. The diagnosis of thrombosis was made by clinical examination, laboratory findings, and echocardiography and cineradiography. Of the 60 patients, 9 patients died early after surgery or before discharge. Most of the deaths were attributed to low cardiac output. The overall hospital mortality was 15%. The overall 10-year actuarial survival rate was 82.8+/-1.6%. In our study, reoperation for thrombosed mechanical prosthesis was not an independent parameter determining mortality. Age was the only statistically important hospital mortality predictor. Of this group, 90% suffered mechanical valve obstruction within the first 5 years after operation. These results suggest that valve re-replacement appears to be a suitable surgical treatment for thrombosis of mechanical prosthetic valves, especially in the young. In these patients subsequent anticoagulation management is necessary.     

心脏瓣膜术后心室辅助治疗

目的 总结瓣膜病变术后重症心衰病人置入心室辅助(VADs)装置时,心脏瓣膜或人工瓣膜处理方法及围术期抗凝管理的经验.方法 回顾1994年1月到2008年6月,宾夕法尼亚大学附属医院心脏中心157例置入VADs病人中,10例为瓣膜术后重症心衰者.对于二尖瓣和三尖瓣病变,无论成形或置换,置入VADs时均未处理原瓣膜或人工瓣膜(环).5例主动脉瓣病变病例置入VADs时,2例用生物瓣膜取代了原机械瓣膜,1例未处理原来生物瓣膜,1例未处理原机械瓣膜,1例取出机械瓣膜,用牛心包封闭主动脉根部.结果 所有病人置入VADs术后应用抗凝治疗.10例病人中,停VAD出院和VAD姑息治疗各1例;转心脏移植4例;4例死亡,3例为多器官衰竭,1例为血栓栓塞事件.结论 瓣膜病变术后置入VADs总的生存率是60%,与非瓣膜病心衰病人置入VADs相比,未增加手术风险.

Abstract：

Objective An increasing number of patients requiring ventricular assist devices (VAD) have had previous valvular corrections,including valve repair,and valve replacement with mechanical or bioprosthetic valves.The operative and peri-operative management of these patients has been varied.Methods A retrospective study of VADs between Jan 1994 and June 2008 revealed 10 patients with previous prosthetic valves requiring management during and after VAD placement.Three patients were supported post-cardiotomy after valve surgery.Two patients were supported due to cardiogenic shock postopera-tively.Four patients were supported as a bridge to transplantation.One patient was supported as a destination therapy.Results The mitral valve was left untreated during VAD implantation regardless of valve repair or replacement.For aortic valves,the mechanical aortic valve was replaced with tissue valve in two patients and left untreated in one case.One patient had tricuspid valve repair previously and was left untouched.All patients with prosthetic valves in aortic,mitral and tricuspid position during VAD support received anticoagulation therapy.There were 4 deaths,and 4 went on to transplantation.One patient weaned from VAD and discharge from hospital.One patient received HeartMate Ⅰ as destination therapy.The most common causes of death were multisystem organ failure and sepsis.One patient had a thromboembolic event.Conclusion The survival rate of 60% is encouraging when compared to overall survival rates.The most common cause of death was multisystem organ failure.Patients with prosthetic valves may be safely managed during VAD support.     

Preliminary Experience with Aspirin for Anticoagulation in Children with Prosthetic Cardiac Valves

Twenty-four children (ages 1 to 18 years, mean 12.2 years) underwent 27 operations for aortic, mitral, or combined aortic and mitral valve replacement. There was 1 operative death. Of the 23 operative survivors (12 aortic, 8 mitral, 3 combined valve replacement), only 5 were given warfarin for long-term anticoagulation. The remaining 18 (10 aortic, 8 mitral valve replacement) were given aspirin (plus dipyridamole in 5). Twelve of the 18 had at least one mechanical valve (11 Björk-Shiley and Beall valves; 1 Björk-Shiley valve was replaced with a Beall disc valve as the child grew).These 18 patients were followed for 1 to 59 months (mean, 20.4 months). There was no thrombotic, embolic, or bleeding complications. There were 2 late deaths (one cardiac).Review of the available literature indicates that in children with prosthetic cardiac valves, aspirin (with or without dipyridamole) provides adequate protection against thromboemboli and avoids the hemorrhagic complications associated with warfarin.     

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.     

Long-term results of mitral valve repair

(1) Carpentier techniques of repair are the dominant method today because of durability and reproducible results. (2) Mitral valve repair results in high survival, low risk of anticoagulant-related complications, and low risk of infective endocarditis. (3) Long-term anticoagulation is avoided in approximately half of the patients; yet, over the long term, thromboembolism occurs significantly less with repair than with valve replacement. (4) The rate of reoperation after mitral valve repair is not significantly different from that of mechanical valve replacement up to 10 postoperative years. (5) Mitral valve repair for degenerative mitral regurgitation results in a higher freedom from reoperation at 5 years and beyond, compared with rheumatic causes of regurgitation. (6) Ischemic and congenital etiologies for mitral regurgitation demand repair whenever feasible. Results in these patient groups favor repair over other options.     

A 5 1/2 year experience with the St. Jude Medical cardiac valve prosthesis. Early and late results of 737 valve replacements in 671 patients

Between June 12, 1978, and June 12, 1983, 737 St. Jude Medical valves were implanted in 671 patients (431 males, 240 females) ranging in age from 9 months to 82 years (mean 55 years); 16 of these patients (2.3%) were less than or equal to 15 years and 82 (12.2%) were greater than or equal to 70 years. Associated procedures were performed in 28.2% of the 500 aortic valve replacements, 13.3% of the 105 mitral valve replacements, and 10.6% of the 66 double mitral and aortic valve replacements. Hospital mortality (less than or equal to 30 days) was 3.6% (18/500 patients) for aortic, 4.7% (5/105 patients) for mitral, and 0% for double valve replacement. Only one of these 23 hospital deaths was possibly valve-related. Complete follow-up was achieved during December, 1983, and January, 1984, to provide a minimum follow-up of 6 months. Follow-up has been 100% for a total of 1,619 patient-years, with a mean follow-up of 2 1/2 years. There were 41 late deaths (6.1%): 30 in the aortic group, eight in the mitral group, and three in the double valve replacement group. Fourteen (34.2%) of these late deaths have been considered valve-related. At 5 1/2 years, the actuarial survival rate, hospital mortality excluded, is 91% for aortic, 90% for mitral, and 95% for double valve replacement. Functional improvement of these patients is quite satisfactory: Preoperatively, 60.3% were in Class III or IV of the New York Heart Association, whereas postoperatively, 99.5% of the patients are in Class I or II. As 78 patients (65 aortic, 10 mitral, and three double valve replacement) did not receive anticoagulation therapy for a total period of 84 patient-years, the incidence of valve thrombosis, systemic embolism, and sudden or suspicious deaths in this group was compared with that in a group of 630 patients (including 60 patients from the first group who were given anticoagulants afterwards) subjected to long-term anticoagulation for a total period of 1,535 patient-years. A significantly higher incidence of valve thrombosis and systemic embolism was observed in the absence of anticoagulation. Anticoagulant-related complications occurred in 10 patients, with an incidence of 0.65/100 patient-years. On the basis of this 5 1/2 years of experience, the St. Jude Medical valve appears to be an excellent mechanical prosthesis for cardiac valve replacement, in terms of hemodynamic performance and low thrombogenicity, in patients receiving anticoagulants.