Comparison of porcine valve xenografts with mechanical prostheses. A 7 1/2 year experience

A total of 479 valve replacements were performed in 469 patients for aortic, mitral, and tricuspid disease. A total of 529 valves were implanted (311 Carpentier-Edwards, 118 Hancock, 94 Bj?rk-Shiley, and six other mechanical valves). Of the 479 operations, 51.1% (245) were carried out in male patients and 48.9% (234) were carried out in female patients. The mean age was 57.6 years; however, 28.6% (137) of the operations were performed in patients over 65 years of age. One hundred five patients (21.9%) had had previous cardiac operations of one type or another. Follow-up was 99.6% and the average length of follow-up was 36.2 months. The overall operative mortality was 5.6%. The operative mortality in the isolated aortic valve replacement group was 2.0% and that in the mitral valve replacement group, 4.4%. There was a 5.9% valve explant rate in the Hancock series; however, no valve explants were required because of valve dysfunction in either the Carpentier-Edwards or the Bj?rk-Shiley groups. The thromboembolic rate in the aortic valve position was 2.4, 1.1, and 2.1 emboli per 100 patient-years in the Hancock, Carpentier-Edwards, and Bj?rk-Shiley groups, respectively. The thromboembolic rate in the mitral valve position was 2.8, 2.2, and 1.0 emboli per 100 patient-years in the Hancock, Carpentier-Edwards, and Bj?rk-Shiley groups, respectively.     

Operative results of tricuspid valve replacement with St. Jude Medical prosthesis

Since 1974, 14 patients underwent tricuspid valve replacement (TVR) with prosthetic heart valves. Hardy's operation was undergone in 2 patients with Ebstein's anomaly and mitral valve surgery or multiple valve surgery were undergone in 9 patients with rheumatic valvular disease, concomitantly. Four types of prosthetic heart valves were used in the tricuspid position, i.e. 2 Starr-Edwards prostheses, 1 Hancock xenograft, 1 Bj?rk-Shiley prosthesis and 12 st. Jude Medical prostheses. The operative mortality rate was 14.3% (2/14) and 2 hospital deaths were due to low cardiac output syndrome. Twelve survivors have been followed with a maximum follow-up of 13 years and the mean of 4.7 years. There were 3 late deaths due to congestive heart failure and prosthetic valve endocarditis (PVE) of the aortic Bj?rk-Shiley prosthesis. There was 1 PVE of the tricuspid Starr-Edwards prosthesis and 1 thrombosis of the tricuspid Bj?rk-Shiley prosthesis, but no thrombosis and no other valve-related complications of SJM prostheses in the tricuspid position. The post-operative NYHA function class improved satisfactorily in 9 survivors. Judging from our relatively satisfactory post-operative results in TVR cases using SJM prostheses, SJM prosthesis in the tricuspid position is one of advisable prosthesis to get satisfactory hemodynamic improvement post-operatively.     

Three-year clinical results with the Monostrut Bj?rk-Shiley prosthesis

Between November 1981 and June 1983, 351 patients underwent valve replacement with the Monostrut Bj?rk-Shiley prosthesis. There were 214 aortic valve replacements, 101 mitral valve replacements, and 31 double (aortic and mitral) valve replacements. Four patients had valve implanted in the tricuspid position, and one patient underwent exchange of a valved, extracardiac conduit. Mean age was 61 years (range 2 to 78) and 186 (53%) were male. Concomitant procedures were performed in 52 patients (15%) and 17 (5%) were emergency operations. Early mortality (4.3%) was related to New York Heart Association Functional Class IV, emergency operation, or the presence of a concomitant procedure. Follow-up was 100% and covered 870 patients-years (mean 2.6 years per operative survivor). Postmortem examination was performed in 38 (79%) of the 48 fatalities. Only one patient suffered a sudden, unexplained death. The 3 year survival rate (early mortality excluded) was 88.6% (aortic valve replacement 89.2%, mitral valve replacement 89.3%, and double valve replacement 82.5%). The 3 year freedom from thromboembolism in patients receiving anticoagulants was as follows: aortic valve replacement 97.5%, mitral valve replacement 92.8%, and double valve replacement 100%. There were no instances of valve thrombosis or fatal embolism. In contrast, there were two instances of aortic valve thrombosis among 34 patients having aortic valve replacement without anticoagulation. The 3 year freedom from valve failure (modified Stanford definition) was as follows: aortic valve replacement 96.0%, mitral valve replacement 93.9%, and double valve replacement 89.7%. There were no mechanical failures. In conclusion, the Monostrut Bj?rk-Shiley valve showed a low incidence of complications. There were no mechanical failures, no fatal emboli, and, when anticoagulants were administered, no valve thromboses.     

Selection of valve prosthesis, reoperation and late result--surgical technique of reoperation with Bj?rk-Shiley prosthesis

Late result of Bj?rk-Shiley prosthesis selected in the aortic and mitral position for valve replacement was reviewed on 222 cases in our 10 years clinical experience. Late survival was 93.8% (5 yrs), 83% (10 yrs) in the aortic position, 94% (5 yrs) and 80% (10 yrs) in the mitral position. Valve-related complication by Bj?rk-Shiley prosthesis was very low in incidence as compared with that published by other institution with respects to thromboembolism, prosthetic valve endocarditis, reoperation, anticoagulation-related bleeding. Inflammatory aortic valve disease which developed valve detachment in the aortic position with Bj?rk-Shiley valve was treated with double-suture technique in the aortic annulus and fixation of the graft with the inside of sinus of Valsalva, en-bloc reconstruction with composite graft using Bj?rk-Shiley valve inside of the sinus Valsalva without touch to coronary ostium. The other surgical procedure was translocation method using Bj?rk-Shiley prosthesis. Our clinical results suggest that Bj?rk-Shiley prosthesis is still recommended in the aortic and mitral positions from low incidence of valve-related complication and good late survival.     

A five-year appraisal and hemodynamic evaluation of the Bj?rk-Shiley Monostrut valve

Two hundred forty-four Bj?rk-Shiley Monostrut valves were implanted in 225 consecutive patients from October 1983 to December 1988. Aortic valve replacement was performed in 90 patients, mitral valve replacement in 118, and double valve replacement in 16 patients. One patient had tricuspid valve replacement. There were 100 female patients and 125 male patients with a mean age of 54 years (range 2 to 71 years). Present data were completely available for all patients. The cumulative follow-up was 541 patient-years with a mean of 2 years, 5 months. The closing date for follow-up was July 1989, and the closing interval was 2 months. The early mortality rate was 3.1%, and the late mortality rate, 3.1%. The 5-year survival rate was 88% +/- 2.0%: 87% +/- 3.0% for aortic valve replacement, 91% +/- 3.3% for mitral valve replacement, and 75% +/- 9.6% for double valve replacement. The actuarial rates of freedom from thromboembolism at 5 years were 93% +/- 3.2% for aortic, 96% +/- 1.4% for mitral, and 94% +/- 6.1% for double valve replacement. There were no instances of structural valve deterioration. Actuarial rate of freedom from valve-related morbidity and mortality was 86% +/- 2.0% at 5 years: 86% +/- 9.5% for aortic, 87% +/- 3.3% for mitral, and 75% +/- 7.3% for double valve replacement. Effective valve areas (average) of 12 mitral and 12 aortic valve prostheses were calculated at rest and during bicycle exercise: 2.4 cm2 at rest and 2.8 cm2 during exercise in 27 mm aortic valves, 2.4 cm2 at rest and 3.0 cm2 during exercise in 25 mm aortic valves, 2.0 cm2 at rest and 2.4 cm2 during exercise in 27 mm mitral valves, and 2.6 cm2 at rest and 2.5 cm2 during exercise in 29 mm mitral valve. On the basis of our follow-up period of 5 years, we have judged the Bj?rk-Shiley Monostrut valve reliable, with a low incidence of valve-related morbidity and with acceptably satisfactory hemodynamic characteristics at rest and during exercise.     

Surgery for atrial fibrillation using radiofrequency catheter ablation

OBJECTIVE: We present the results obtained in 40 patients with chronic atrial fibrillation using direct intraoperative radiofrequency to perform atrial fibrillation surgery. METHODS: Between April 2001 and June 2002, 40 patients underwent surgery for atrial fibrillation using radiofrequency ablation and cardiac surgery at the Department of Cardiovascular Surgery of the University of Bologna [corrected]. There were 8 men and 32 women with a mean age of 62 +/- 11.6 years (range: 20 to 80 years). RESULTS: Concomitant surgical procedures were: mitral valve replacement (n = 13), mitral valve replacement plus tricuspid valvuloplasty (n = 11), combined mitral and aortic valve replacement (n = 8), and combined mitral and aortic valve replacement plus tricuspid valvuloplasty (n = 5). Moreover, 1 patient underwent tricuspid valvuloplasty plus atrial septal defect repair, another required aortic valve replacement plus coronary artery bypass graft, and a third underwent aortic valve replacement. After the mean follow-up time of 16.5 +/- 2.5 months survival was 92.8% and the overall cumulative rate of sinus rhythm was 88.5%. CONCLUSIONS: We conclude that the radiofrequency ablation procedure is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent cardiac surgery (88.5% of our study population).     

Comparative analysis of mechanical and bioprosthetic valves after aortic valve replacement

Comparative long-term performance characteristics of Bj?rk-Shiley mechanical and bioprosthetic valves were analyzed for patients undergoing aortic valve replacement between 1976 and 1981. A total of 419 patients received either a standard Bj?rk-Shiley (n = 266) or bioprosthetic (porcine, n = 126, or pericardial, n = 27) aortic valve. Cumulative patient follow-up was 1,705 patient-years; the average patient follow-up was 4.1 +/- 2.7 years. Survival data were obtained for all but 11 patients (97% complete follow-up) up to 9 years after operation. Survival at 5 years was 81% +/- 4% (+/- standard error) for Bj?rk-Shiley and for bioprosthetic valve recipients. Valve failure in the Bj?rk-Shiley group was predominantly due to valve-related mortality and did not result from structural failure. Patients with bioprosthetic valves experienced valve failure as a result of prosthetic valve endocarditis and intrinsic valve degeneration. Although patients with bioprostheses experienced a lower incidence of valve-related morbidity than Bj?rk-Shiley valve recipients (p less than 0.03), no difference could be demonstrated in the incidence of valve-related mortality or valve failure at 5 years between bioprosthetic and Bj?rk-Shiley valves. Mortality rate from valve failure was higher for Bj?rk-Shiley (86%, 12/14) than bioprosthetic valves (36%, 5/14) (p less than 0.01).     

Mitral and aortic valve replacement with tricuspid annuloplasty in a patient suffering from hereditary spherocytosis

A 51-year-old woman was admitted with increasing shortness of breath. Preoperative evaluation disclosed MSr + ASr + TR. She had been undergone a splenectomy at 35-year-old for hereditary spherocytosis (HS). The patient underwent successful mitral valve replacement with a No. 25 Bj?rk-Shiley (BS) valve, aortic valve replacement with a No. 21 BS valve, and tricuspid valve annuloplasty by means of membrane oxygenator (COBE). Haptoglobin and poloxamer 188 were used for prevention of hemolysis during extracorporeal circulation. No significant hemolysis occurred intra-or postoperatively. A very rare case of open heart surgery associated with HS was reported.     

Clinical evaluation of the Bj?rk-Shiley disc valve in the tricuspid position. Long-term results

Between 1971 and 1981, 1210 Bj?rk-Shiley prostheses were implanted. Of these, 79 were in the tricuspid position, comprising 30 triple valve replacements, 46 mitral plus tricuspid, and 3 isolated tricuspid replacements. The ages ranged from 10-55 years (mean 45 years). Sixty-three patients (80%) were in NYHA grades III or IV preoperatively. Thirteen patients died in hospital after surgery (16.5%). The 66 survivors have been followed for up to 16 years (mean 7.5 years). There have been 37 late deaths (7.5 per patient year). Twelve were valve-related: 4 tricuspid complications, 4 mitral complications, 2 prosthetic endocarditis, 1 aortic leak and 1 anticoagulant-related bleed. Twenty-one late deaths were not valve-related, and 4 causes of death are unknown. Expressed actuarially, survival at 5 years was 68%, and at 10 years, 49.4% +/- 12%. Freedom from valve-related death at 10 years was 80.7% +/- 7%. At last follow-up, 90% of the survivors were in NYHA class 1 or 2 with only modest signs of venous hypertension. The commonest life-threatening complication was obstruction of the tricuspid prosthesis by tissue ingrowth. This occurred in 7 patients (1.4% per patient year) 4 were re-operated upon and survived, 3 died. Doppler echocardiography has been carried out on 27 survivors of whom 5 had abnormal pressure-half times but only 3 of these were symptomatic. This series shows that function of the standard disc Bj?rk-Shiley prosthesis in the tricuspid position compares favourably with other prostheses. The problem of tissue ingrowth can be diagnosed by echo Doppler and reoperation successfully carried out.     

Mechanical heart valve prostheses: sound level and related complaints.

In a randomised study, we investigated the sound production of mechanical heart valve prostheses and the complaints related to this sound. The CarboMedics, Bj?rk-Shiley monostrut and StJude Medical prostheses were compared. A-weighted levels of the pulse-like sound produced by the prosthesis were measured in 25 patients after aortic valve replacement. Additionally, 141 patients, 117 after aortic valve replacement, 20 after mitral valve replacement and 4 after double valve replacement were interviewed. The average sound pulse pressure levels were 46.0 +/- 2.9 dB(A) in the Carbomedics group, 55.4 +/- 1.2 dB(A) in the Bj?rk-Shiley monostrut group and 44.1 +/- 4.4 dB(A) in the StJude Medical group, measured at a distance of 1 cm from the chest. The Bj?rk-Shiley monostrut was louder than the other two prostheses (p less than 0.0005). Twenty (14.2%) of all patients had complaints related to the valve sound such as sleeping disturbances, irritation, nervousness or fear. Significantly more patients with a Bj?rk-Shiley monostrut could hear their valve or had complaints when compared to the other two prostheses. Younger patients and patients with a mitral valve prosthesis could hear their valve more often than older patients or patients after aortic valve replacement. We conclude that sound characteristics and related complaints differ considerably among heart valve prostheses.     

Mechanical failure of the Bj?rk-Shiley valve. Incidence, clinical presentation, and management

The experience after implantation of 3,334 Bj?rk-Shiley valves over a 15 year period is described. With a 99.2% follow-up (covering 17,511 patient-years, mean follow-up time 6.3 years) and an autopsy rate of 75% among all fatalities, altogether 19 cases of mechanical failure were documented. There were no mechanical failures among the standard Delrin Bj?rk-Shiley valve (n = 271), the aortic standard Pyrolyte Bj?rk-Shiley (n = 739), or the Monostrut Bj?rk-Shiley valve (n = 377). One of the mitral standard Pyrolyte valves (n = 430) fractured. Among the 1,461 convexo-concave valves, 18 fractured (6/884 with an opening angle of 60 degrees and 12/577 with an opening angle of 70 degrees). The actuarial incidence of mechanical failure at 5 years was 0.6% (with an upper 95% confidence limit of 1.2%) for the 60 degree convexo-concave valve and 2.8% (upper 95% confidence limit of 4.4%) for the 70 degree convexo-concave valve (p less than 0.01). Two groups of valves were especially affected by this complication; the 23 mm aortic 60 degree convexo-concave valve (5 year actuarial incidence 2.2%, upper 95% confidence limit 4.7%) and the 29 to 31 mm mitral 70 degree convexo-concave valve (8.3%, upper 95% confidence limit 14.2%). The hazard function presently indicates a constant (60 degree convexo-concave) or decreasing (70 degree convexo-concave) tendency for mechanical failure. The time interval between the first symptom of mechanical failure and circulatory collapse was significantly (p less than 0.01) shorter after aortic failure than after mitral failure, and no patient with a fractured aortic prosthesis survived long enough to undergo reoperation. The incidence of mechanical failure among patients dying suddenly (but with an autopsy) was 9.6% (95% confidence limits 4.9%-16.6%), and most cases of sudden death were unrelated to the prosthesis. The management of patients with suspected mechanical failure is described. Prophylactic re-replacements are discussed but cannot be generally recommended at present.     

Malfunction of the Bj?rk-Shiley valve prosthesis due to disc defacement--report of two cases of successful reoperation

Derlin-disc model Bj?rk-Shiley valve prosthesis was reoperated due to the disc defacement. One had admitted cerebral embolism which was suggested due to the prosthetic valve malfunction of aortic position and the other had congestive heart failure due to the malfunction of mitral position. These patients had implanted Derlin-disc model Bj?rk-Shiley valve prosthesis in the aortic and mitral position 10 and 11 years ago. One's cineangiocardiography showed mild aortic regurgitation and the other showed mitral regurgitation due to the malfunction of the prosthesis. The episode of cerebral embolism in one patient was suggested due to the malfunction of aortic prosthetic valve, and congestive heart failure in the other patient was due to the malfunction of mitral prosthetic valve. These prostheses which removed at the reoperation were observed with strat shape indentation and distinct of the disc which resulted the malfunction of the prostheses. In patient who replaced with Derlin-disc model Bj?rk-Shiley valve prosthesis should be carefully followed up.     

Post-operative evaluation of a 17 mm diameter Bj?rk-Shiley Monostrut prosthesis for aortic valve replacement--pressure gradient and effective valve area

A 17 mm diameter Bj?rk-Shiley Monostrut prosthesis was implanted in a 64-year-old female for aortic valve replacement in a semi-emergency. This valve was one of the smallest valves which were available in Japan. The patient was admitted because of severe hemolytic anemia and heart failure. Echocardiography showed regurgitation and calcification of Ionescu-Shiley tissue valve which was implanted 5 years ago. The patient's body surface area was 1.2 m2. Because of narrow aortic annulus, we could barely implant a 17 mm diameter Bj?rk-Shiley Monostrut prosthesis. The valve function was examined by Brockenbrough method. During catheterization, the heart rate was 85 b/min and cardiac index was 3.00 l/min/m2. In these hemodynamic conditions, simultaneous measurements of aortic and left ventricular pressures revealed only 9 mmHg mean systolic pressure gradient. Similarly, 20 mmHg of pressure gradient across the implanted valve was obtained by Gorlin's formula. We could calculate that the effective orifice area of a 17 mm diameter Bj?rk-Shiley Monostrut prosthesis was 1.0 cm2. Postoperative echocardiography demonstrated 42 mmHg systolic pressure gradient across this prosthesis by Doppler techniques, and left ventricular wall thickness was not decreased. To best our knowledges, this was the first case in which post-operative evaluation such a small prosthesis was measured.     

Late thrombosis of the Bj?rk-Shiley tilting disc valve in the tricuspid position. Thrombolytic treatment with streptokinase

The main complication after implantation of a Bj?rk-Shiley tilting disc valve in the tricuspid position is late thrombotic obstruction. Of 28 patients with tricuspid valve replacement (16 with mitral, aortic, and tricuspid valve replacement; 12 with mitral and tricuspid valve replacement), with a mean follow-up of 5.2 years, seven (25%) had thrombosis of the tricuspid prosthesis. Three patients had a recurrent thrombotic malfunction, for a total of ten thrombotic malfunctions in 146 patient-years, a rate of 6.8 per 100 patient-years. Thrombosis occurred late in all patients. Clinical deterioration presented with signs of congestive heart failure. In all patients the click of the tricuspid prosthesis was not audible and new diastolic or systolic murmurs were. The diagnosis was confirmed with cineradiography and bidimensional echocardiography (immobile disc, diminished opening angle of the disc). Thrombolytic treatment with streptokinase was used in all seven patients. Two patients required 12 hours of therapy and five patients, 24 hours. Thrombolytic treatment was monitored by the thrombin time. Complete regression of clinical, cineradiographic, and echocardiographic signs fo thrombosis was seen in all seven patients during the first 24 hours of therapy. There were no bleeding complications. In one patient clinical signs of mild pulmonary embolism occurred and were confirmed with chest radiographs. Follow-up, after successful treatment, extends from 4 to 30 months (mean 16.5 months). In four patients long-term results are excellent: There have been no clinical, cineradiographic, or echocardiographic signs of rethrombosis of the tricuspid prosthesis during the follow-up. Rethrombosis of the tricuspid prosthesis was observed in three patients 4, 7, and 14 months after initial treatment with streptokinase. Repeat thrombolytic treatment with streptokinase was successful in all three of these patients. Our experience with streptokinase treatment of thrombosis of tricuspid Bj?rk-Shiley prostheses indicates that this form of treatment should always be applied before surgical intervention.     

Downward displacement of aortic anulus leading to aortic and mitral regurgitation

A rare case of combined aortic and mitral regurgitation resulting from downward displacement of the aortic anulus is reported. The patient was treated successfully with an aortic valve replacement with a Bj?rk-Shiley valve prosthesis, which was anchored at the normal site of the aortic anulus. No procedures were performed on the mitral valve, but mitral regurgitation was not evident postoperatively.     

Early and late results of aortic valve replacement. A series of 510 patients

Aortic valve replacement was performed in 510 patients (Bj?rk-Shiley valves in 93%), with concomitant surgical procedures in 146 cases. The patients were grouped according to technique of myocardial protection: Group I (n = 98) selective coronary perfusion, group II (n = 82) topical cooling, and group III (n = 330) cold crystalloid cardioplegia and topical cooling. The early mortality rate was 5.7% overall: Among patients with isolated aortic valve replacement in groups I, II and III it was 8.4, 1.7 and 1.3%, respectively, and among those with additional surgery 40.0, 12.5 and 8.4%. Myocardial infarction and low cardiac output were responsible for 65.5% of the early deaths. Follow-up ranged from 2 months to 16 11/12 years, totalling 2,859 patient years. In patients with isolated aortic valve replacement and Bj?rk-Shiley prosthesis, the incidence of valve-related late complications/100 patient years was 0.49 for thromboembolism, 0.82 for anticoagulant-related haemorrhage and 0.49 for prosthetic valve endocarditis. There was no thrombotic encapsulation in aortic position. Survival at 5 and 10 years was 83% and 72%. Aortic valve replacement is a safe procedure and concomitant operations do not unreasonably increase risks.     

Long-term comparative analysis of the Bj?rk-Shiley and Hancock valves implanted in 1975

The long-term results in all patients undergoing isolated mitral, aortic, or double mitral-aortic heart valve replacement operated upon in 1975 has been retrospectively analyzed. A total of 153 patients received the standard Bj?rk-Shiley (flat pyrolytic disc) mechanical prostheses and 150 patients received the noncomposite Hancock porcine xenograft. Overall operative mortality was not significantly different between groups. All patients receiving a Bj?rk-Shiley prosthesis, but none in the Hancock group, received long-term anticoagulant therapy. Medium and long-term actuarial survival rates (5 and 10 years postoperatively) were comparable for the two groups (88% for Bj?rk-Shiley and 84% for Hancock [NS] at 5 years; 86% for Bj?rk-Shiley and 80% for Hancock at 10 years [NS]). The incidence of systemic embolism was similar in the two groups (1.6% +/- 0.4% per patient-year for the Bj?rk-Shiley group and 1.3% +/- 0.3% per patient-year for the Hancock group [NS]). Also the incidence of endocarditis was similar (0.6% +/- 0.2% per patient-year for the Bj?rk-Shiley group and 0.8% +/- 0.3% per patient-year for the Hancock group [NS]). In the Hancock group the overall incidence of reoperations was significantly higher than in the Bj?rk-Shiley group (4.2% +/- 0.6% per patient-year versus 0.9% +/- 0.3% per patient-year (p = 0.001). The major cause for reoperation in the Hancock group was primary tissue failure (3% +/- 0.5% per patient-year). In the Bj?rk-Shiley group the major cause of reoperation was valve thrombosis (0.5% +/- 0.2% per patient-year). Therefore, accepting the fact that other bioprostheses may behave differently from the Hancock noncomposite xenograft, we currently restrict our indications for valve replacement with bioprostheses.     

Ten years' experience with the Bj?rk-Shiley tilting disc valve.

More than 10 years of clinical experience with 1,800 consecutive valve replacements with the Bj?rk-Shiley tilting disc valve were focused on improving its durability, flow dynamics, thromboresistance, and in vivo functional control. Although the original Delrin disc functions excellently after 10 years in the human circulation, the durability of the prosthetic valve was further prolonged by the introduction of pyrolytic carbon as disc material. The opening mechanism was also reinforced by integrating the bearing struts with the valve ring. No other presently available heart valve prosthesis shows such a low resistance to flow for a given tissue diameter. The disc was equipped with a ring-shaped radiopaque marker that permitted noninvasive functional control. The 5 year survival rates were 82% after aortic, 66% after mitral, and 66% after mitral and aortic valve replacements, including the operative mortality rates. The incidence of systemic emboli was 0.7% per year after aortic, 4.2% per year after mitral, and 2.2% per year after mitral and aortic valve replacements with anticoagulation treatment. The incidence of obstruction by thrombosis was 0.3% per year for aortic, 1.3% per year for mitral, and 2.3% per year tricuspid prostheses. The new convex-concave model decreases the stagnation zone behind the disc, decreases emboli from 4.2% to 1.2% per year after mitral valve replacement, and has a lower gradient.     

Clinical results after mitral valve replacement with the Bj?rk-Shiley disc prosthesis

Between September 1971 and June 1985, 230 Bj?rk-Shiley valves were implanted for mitral valve disease at the Department of Surgery, University of Turku. Concomitant cardiac surgical procedures were performed in 35.2% of the cases. The follow-up period was between 1 month-13 years 4 months, with a total follow-up of 986 patient years. The early mortality was 4% in patients with isolated MVR and 10% where concomitant procedures had to be performed. Since the use of cold cardioplegia there has been no mortality for isolated MVR and the mortality rate for patients with concomitant procedures has been 3.9%. During the follow-up the rate of thromboembolism was 0.4 per 100 patient years, that of thrombolic encapsulation 0.4 and anticoagulant-related haemorrhage 0.7. Ninety-five per cent of the patients were free from thrombotic or embolic complications at 5 and 10 years after surgery. The survival rate was 79% at 5 years and 72% at 10 years. Considering these results we still prefer the Bj?rk-Shiley valve in mitral valve replacement.     

Fourteen years' experience with the Bj?rk-Shiley tilting disc prosthesis

Between 1970 and 1984, 1,574 Bj?rk-Shiley valve prostheses have been implanted in 1,171 patients in Glasgow. Between 1970 and 1980, 1,023 standard disc prostheses were implanted in 729 patients: 184 had aortic valve replacement, 323 mitral, and 222 multiple valve replacement. Between 1980 and 1984, 551 convexo-concave valves were implanted in 442 patients: 125 had aortic, 228 mitral, and 89 multiple valve replacement. Concomitant coronary artery bypass grafting was performed in 9.2% of the latter group as compared with 2.7% of the earlier group. The overall hospital (30 day) mortality for the group with the standard disc prosthesis was 10.4% and for patients with the convexo-concave prosthesis, 7.0%. Cumulative follow-up extends to 4,125 patient-years--standard disc group 3,378 patients-years, range 4 to 14 years (mean 5.2 years); convexo-concave group 747 patient-years, range 1.5 to 5.3 years (mean 1.9 years). The late mortality is 3.8% per patient-year--standard disc group 2.9% per patient-year and convexo-concave group 4.3% per patient year (no significant difference). Actuarial survival rate at 12 years for the whole group, excluding operative deaths, is 69.4% +/- 6.3%. The freedom from all valve-related complications at 12 years is 65.9% +/- 6.5%. there is no significant difference in the incidence of most major complications between the standard disc and convexo-concave prostheses apart from the occurrence of mitral valve thrombosis (p less than 0.05) in the standard disc group and outlet strut fracture (p less than 0.005) in the convexo-concave group. These results confirm the excellent long-term performance of the Bj?rk-Shiley tilting disc prosthesis.