Tricuspid valve replacement with the St. Jude Medical valve

A study was conducted on 20 patients who underwent tricuspid valve replacement (TVR) with the St. Jude Medical (SJM) valve. Isolated TVR was performed on 9 patients, and additional mitral, or mitral and aortic valve replacements were performed on 11 patients. Four patients (20%) died in the early postoperative period, but there were no deaths related to the SJM valve in the tricuspid position. The mean follow-up period of the 16 survivors was 74.4 months, and there have been no deaths during the follow-up period. The postoperative actuarial survival rate was 80%, 10 years after surgery. Three patients, representing 0.25%/patient-months, developed valve thrombosis, the valve thrombosis-free rate being 72.8%, 10 years after surgery, while entrapment of a leaflet by endothelial pannus was found in one patient, representing 0.08%/patient-months. Thus, the incidence of all prosthetic valve-related complications was 0.34%/patient-months, and the postoperative complication-free rate was 65.3%, 10 years after surgery. The medium-term follow-up study of TVR with the SJM valve revealed no prosthetic valve-related deaths and a relatively low incidence of prosthetic valve-related complications. However, as with other mechanical valves, valve thrombosis was a major risk posed by the SJM valve in the tricuspid position.     

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.     

Long-term survival after tricuspid valve replacement. Results with seven different prostheses.

The experience with tricuspid valve replacement (TVR) with seven different prostheses, alone or combined with replacement of other valves, in 73 patients (64 rheumatic and nine nonrheumatic) between 1964 and March, 1975, at the University of Alberta Hospital has been reviewed. Early and late mortality rates in rheumatic patients were 41 and 23 percent, respectively (36 percent being alive after a mean of 5.6 years), compared to 33 and 11 percent, respectively, in the nonrheumatic patients (56 percent being alive after a mean of 2 years). Of all survivors, 88 percent were functionally improved. Among the rheumatic patients: (1) 88 percent had organic tricuspid disease; (2) of the 39 patients with tricuspid insufficiency who underwent corrective mitral surgery 7 years before TVR, the tricuspid insufficiency had progressed over the 7 years; (3) the number of patients with tricuspid insufficiency had increased (39 versus 59) over the same 7 year period; (4) a high early mortality rate was encountered in those who were preoperatively in New York Heart Association (N.Y.H.A.) Class IV, or who had cardiomegaly, or pulmonary hypertension, or poor ventricular function, or organic disease, or reoperation; (5) the percentages of survivors with different prostheses were: Starr-Edwards, 31 percent; Beall-Surgitool, 14 percent; Kay-Shiley, 46 percent, Bj?rk-Shiley, 50 percent; Lillehei-Kaster, 100 percent; Cutter-Smeloff and Wada-Cutter, nil. Among the nonrheumatic patients, two with the Cutter-Smeloff, two with the Beall-Surgitool, and one with the Lillehei-Kaster were alive after 14, 37, and 15 months, respectively. Among all survivors of TVR, late thrombus and pannus developed on both ball and disc prostheses (Starr-Edwards, two; Cutter-Smeloff, one; Lillehei-Kaster, one). These findings suggest that TVR should be performed earlier in rheumatic patients to reduce the operative mortality rate and that the Lillehei-Kaster prosthesis is probably most suitable for TVR.     

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.     

Thrombosis of two St. Jude Medical prostheses in one patient after triple valve replacement. Case report and review of the literature

Reports of experience with the St. Jude Medical (SJM) valve state that thrombosis of the prosthesis is a rare complication. In a 57-year-old woman, reoperation was necessary 12 months after triple valve replacement using SJM prostheses because of thrombosis of the valves in the tricuspid and aortic positions. Dysfunction of both mechanical valves was detected clinically by changing heart sounds and the appearance of murmurs. Echocardiography and cinefluoroscopy confirmed at least one fixed leaflet of the tricuspid prosthesis, but abnormalities of the aortic prosthesis could not be detected. At reoperation, the SJM prosthesis in the tricuspid position was almost completely thrombosed and was replaced by an Ionescu-Shiley bioprosthesis. A thrombotic formation at the hinge point of the SJM aortic prosthesis was removed. To our knowledge, this is the first report of a thrombotic complication of two SJM prostheses after triple valve replacement in one patient.     

Acute thrombotic obstruction with Bj?rk-Shiley valves: diagnostic and surgical considerations

Eight patients have had thrombotic obstruction of a prosthetic valve since 1971, six mitral valves and two aortic. All eight patients had a Bj?rk-Shiley valve. During the same period 159 Bj?rk-Shiley valves were placed, 85 in the mitral and 74 in the aortic area. This represents a valve thrombotic occlusive incidence of 4.4 percent in our series, 5.9 percent of mitral and 2.7 percent of aortic prostheses. Among the six patients with mitral prostheses only one survived. The two patients with occluded aortic valves survived. The onset of symptoms was very abrupt in most patients and progressed very rapidly. Acute pulmonary edema was observed in five patients. Anticoagulation was considered inadequate in all patients. Aspirin or dipyridamole was being used in seven patients at the time of thrombosis. The data indicate a high frequency of thrombotic occlusion of Bj?rk-Shiley valves in the absence of full anticoagulation with warfarin derivatives and emphasizes the urgent need for surgery once valve thrombosis is suspected.     

In vitro hydrodynamic characteristics of heart valves in tricuspid position

At present there are many problems concerning the choice of heart valve for cardiac valve replacement in the tricuspid position. Thus, we devised an attachment head for the prosthetic valve in order to evaluate the hemodynamic characteristics of four clinically-available mechanical prosthetic valves and two xenografts in the pulsatile circulation system in the tricuspid position. Six artificial cardiac valves were used in this experiment; St. Jude Medical (SJM), Starr Edwards ball (S-E), monostrut Bj?rk Shiley (B-S), Omnicarbon, Carpentier Edwards (CE) supraannular, CE-pericardial whose tissue annulus diameter was 27 mm. The experimental instrument similar to that of Umezu et al, was prepared to determine the mean pressure gradient, output and calculated orifice area of each valve. Since many of the patients who must undergo tricuspid valve replacement have severe multi valvular diseases with atrial fibrillation, we experimented also under the condition of atrial fibrillation. At sinus rhythm under pulsation flow, no significant difference was shown in cardiac output between the various valves, but pressure gradient was higher with xenografts than with mechanical prostheses, and the SJM valve showed the widest efficient valve orifice area. The reduction rate of the efficient valve orifice area from sinus rhythm to atrial fibrillation was about 10% in the SJM valve, which was better rate than other heart valves. We observed significant differences in cardiac output, pressure gradient and efficient orifice area at sinus and atrial fibrillation rhythm. (p less than 0.01).     

Left ventricular outflow tract obstruction with mitral valve replacement in small ventricular cavities

The inference that mitral valve replacement (MVR) may produce left ventricular outflow tract (LVOT) obstruction has been made, but no comparative hemodynamic studies with various types of prostheses have been done. The purpose of the present study was to compare the gradients created across the LVOT with MVR in young sheep with small left ventricular cavities. Mitral valve replacement was accomplished using cardiopulmonary bypass and hypothermic cardioplegic arrest. Five animals were used for each of the following valves studied: 25-mm Ionescu-Shiley bovine pericardial valve, 25-mm Hancock porcine aortic valve, 2M-6120 28-mm Starr-Edwards ball-valve prosthesis, 25-mm Bj?rk-Shiley 60-degree flat tilting-disc prosthesis, and 25-mm St. Jude Medical hemidisc valve. Gradients across the LVOT were measured after MVR and then during infusion of isoproterenol hydrochloride (0.05 micrograms/kg/min). Following MVR, only the Starr-Edwards valve produced an LVOT gradient (32 +/- 23 mm Hg). Substantial gradients after MVR were seen, however, with isoproterenol administration with the Ionescu-Shiley (47 +/- 4 mm Hg), Hancock (13 +/- 8 mm Hg), and Starr-Edwards (65 +/- 30 mm Hg) valves but not with the low-profile valves (Bj?rk-Shiley and St. Jude Medical). The results of the present study demonstrate that MVR can produce LVOT obstruction. The greatest degree of obstruction was with the high-profile mechanical and bioprosthetic valves.     

Mechanical valve thrombosis in the tricuspid position--reoperative management of 2 cases

Because valve thrombosis occurred after the tricuspid valve replacement with the mechanical valve, we performed replacement of the mechanical valve with the bovine pericardial valve in two cases. Case 1: The patient, at 13 years old, received open-heart surgery to correct infundibular stenosis. At 23 years of age, decortication and tricuspid valve replacement (TVR) with a phi 31 mm Bj?rk-Shiley valve were performed due to constrictive pericarditis and tricuspid regurgitation developed after the initial operation. Thrombosis of the mechanical valve occurred after the TVR. Treatment with urokinase for the thrombolytic therapy failed to improve the valve opening. Finally 12 years after the TVR, replacement of the mechanical valve with a phi 27 mm Carpentier-Edwards bovine pericardial valve was performed. Case 2: The patient, at 21 years old, received open-heart surgery to close an atrial septal defect. At 40 years of age, mitral and tricuspid valve replacements were performed because regurgitation developed in both valves. The mitral and tricuspid valves were replaced with phi 27 mm and 31 mm St. Jude Medical valves, respectively. Thrombosis of the mechanical valve used for the TVR occurred 2 months after the replacement. The mechanical valve was replaced with a phi 27 mm Carpentier-Edwards bovine pericardial valve. In both cases, subjective symptoms improved and prosthetic valve complications did not occur after re-replacement with the bovine pericardial valve. These cases suggested that for TVR a bovine pericardial valve of sufficient size would be better to select than a mechanical valve.     

The Clinical Life History of Explanted Prosthetic Heart Valves

This report analyzes 118 prosthetic heart valves obtained from 97 patients at reoperation (96) or at postmortem examination (22). The number obtained from the mitral, aortic, and tricuspid positions were 78, 32, and 8, respectively. Duration of implant ranged from one day to 12.3 years. Valves showing the least long-term wear were the Starr-Edwards metal strut-silicone ball and the Björk-Shiley. Moderate long-term durability was provided by the Beall and Starr-Edwards cloth-covered composite-seat prostheses while short-term durability was given by Hancock and Carpentier valves. Reoperation for valve-related causes was performed for 46 of 47 Beall valves, which demonstrated stenosis, hemolysis, and incompetence from component wear, 6 of 27 Björk-Shiley prostheses for valve thrombosis or thromboembolism or both, and 11 of 17 porcine prostheses because of calcification (4) or cusp perforation or rupture. Analyses of wear and fatigue of mechanical valves demonstrated that use of ultrahard materials (pyrolyte carbon, titanium, stellite 21) provided superior durability in contrast to polymeric solids or fabrics with poor abrasion and impact characteristics. Further, cloth and disc wear were evident as early as 0.5 year after implant and appeared to be complete by 4 years. Completeness of healing after 24 months was not related to the type of fabric material used or its construction.This study suggests that mechanical valves made from hard materials have long durability when properly implanted and require fastidious prophylaxis against infection and thromboembolism. The findings of early cusp perforation or rupture in the aortic position and leaflet calcification, stiffening, or disruption in the mitral position for porcine prostheses suggest that frequent and careful examinations of patients with these prostheses are required to detect early signs of stenosis or incompetence and that early reoperation is required before catastrophic valve failure necessitates emergency prosthetic valve replacement.     

The Bj?rk-Shiley tilting disc valve in the tricuspid position. 10-year experience

Ten-year experience of tricuspid valve replacement with the Bj?rk-Shiley pyrolytic carbon disc is reported. Of the twelve patients, one died in association with the operation, due to tracheo-oesophageal fistula. There were four late deaths, two from unknown causes, one during re-replacement of mitral valve and one from carcinoma of the urinary bladder. No patient had thromboembolism, valve thrombosis or subacute infective endocarditis. From the analysis of the hospital records and follow-up data it is concluded that the Bj?rk-Shiley pyrolytic carbon disc prosthesis is a satisfactory substitute for the tricuspid valve.     

Surgical treatment of Ebstein's anomaly. Early and late results in seven consecutive cases.

The surgical treatment of Ebstein's anomaly is discussed on the basis of our experience with 7 patients who underwent operation at this clinic during the last ten years. The age of the patients (2 males, 5 females) ranged from 17 to 47 years (mean 27 years) at the time of operation. Two patients were in functional class II and five in classes III or IV (N.Y.H.A.). The Wolff-Parkinson-White syndrome was concomitant in 2/7 cases and patent foramen ovale or atrial septal defect (ASD) with right-to-left shunt was present in 6/7 cases. The valvular anomaly was typical in 5 patients and stenosis of displaced tricuspid leaflets into right ventricular outflow region was detected in two patients. Tricuspid valve replacement (TVR) with disc valve prosthesis was performed in 5 patients (Bj?rk-Shiley model in 4 cases, Kay-Shiley model in one) and tricuspid valve commissurotomy in two patients. All six patients with interatrial communication underwent closure of this communication simultaneously. One patient had concomitant epicardial mapping and attempted division of the anomalous conduction pathways was unsuccessful. This patient died on the 14th postoperative day from ventricular fibrillation. No other early or late mortality was recorded. Life-long anticoagulation therapy was introduced in all 5 patients with TVR. Thrombotic malfunction of the prosthetic valves necessitated re-operation and new prosthetic valve replacement in two patients 15 and 16 months after the first TVR. One of these patients had recurrent prosthetic thrombosis twice which was successfully treated with streptokinase. The other patient's prosthesis is functioning well 18 months after re-operation. All 6 long-term survivors were improved and remained in good condition, in functional class I, 1, 3, 3, 8, 9, and 10 years, respectively, after operation.     

Nonsurgical correction for thrombosis of a St. Jude Medical tricuspid prosthesis: Report of a case

A 43-year-old woman with rheumatic heart disease underwent replacement of the aortic, mitral, and tricuspid valves using three SJM prostheses. Despite adequate warfarin therapy, routine cineradiography performed on the 40th postoperative day showed one of the leaflets of the tricuspid prosthesis to be “stuck” in the semiclosing position. A thrombosis of the tricuspid prosthesis was successfully treated with a urokinase infusion and mechanical thrombolysis using a pacemaker, following which normal valve function was restored.     

The St. Jude "Silzone" valve: midterm results in treatment of active endocarditis

BACKGROUND: The Silzone-coated St. Jude Medical valve (SJM "Silzone" valve), developed to reduce prosthetic valve endocarditis (PVE), was recalled by SJM due to a higher rate of paravalvular leaks. The aim of this study was to determine the efficacy of the SJM "Silzone" valve in avoiding PVE and to evaluate the frequency of paravalvular leaks, when the valve was used exclusively for active bacterial endocarditis. METHODS: From January 1998 to December 1999, the SJM "Silzone" valve was implanted in 40 consecutive patients with active endocarditis (20 aortic, 14 mitral, and 6 both valves). Late transesophageal echocardiography was performed in 87% of survivors, and transthoracic echocardiography in the remaining 13%. Follow-up was 100%. RESULTS: Hospital mortality was 17.5%. Early PVE occurred in 2 of 40 patients (5%). There were two late deaths without signs of recurrent PVE. A hemodynamic relevant paravalvular leak necessitating reoperation was seen in 2 patients within 6 months after operation. The rate of a minor paravalvular leak was 13% (4 of 31 patients). CONCLUSIONS: The SJM "Silzone" valve when implanted for active bacterial endocarditis does not give better results than other mechanical prostheses with regard to early recurrence of endocarditis. The rate of a hemodynamic relevant paravalvular leak requiring reoperation seems rather high during the early postoperative period, whereas the occurrence of minor paravalvular leaks is comparable with that of other mechanical prostheses. Routine observation, recommended for all patients with mechanical heart valves, is also sufficient for patients with the SJM "Silzone" valve.     

Aortic valve replacement with the Bj?rk-Shiley tilting disc valve prosthesis. Clinical experiences in 50 cases.

Single aortic valve replacement with the Bj?rk-Shiley tilting disc valve prosthesis has been performed in 50 patients since April 1971. None of the total of six deaths (12.0%) was attributable to malfunction of the prosthesis or to embolic complications. Follow-up examination showed insignificant or moderate prosthetic regurgitation in two patients and moderate paravalvular leakage in one patient. A slight intravascular haemolysis was found in two cases, one of them without marked regurgitation, and a slight reversible cerebral thrombo-embolism in two. Clinical improvement was observed in 43 of the 44 survivors during the 6 to 12 months of follow-up. Objective evidence of improvement was verified by cardiac catheterization following the replacement of aortic valve with the Bj?rk-Shiley tilting disc prosthesis.     

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.     

In vitro hemodynamic characteristics of prosthetic heart valves

The functional characteristics of the prosthetic heart valve are the hemodynamic characteristics when it has been ideally attached; in clinical practice, however, it is seldom that this artificial valve is ideally put in position because of the modality of changeable valve angle in deformed annulus and the narrow aortic root, orientation of the valve, anatomical factors, etc. Thus, we devised an attachment head for the prosthetic valve whose angle can freely be varied in order to evaluate the hemodynamic characteristics of five clinically-available mechanical prosthetic valves and two xenografts in the pulsatile circulation system in the mitral position by changing the angle and orientation of the valve attachment. The prosthetic valves used were St Jude Medical (SJM), Starr-Edwards ball (S-E), monostrut Bj?rk-Shiley (mB-S), Omniscience (OS), Omnicarbon (OC), Carpentier-Edwards Supra-annular (C-Es) and Carpentier Edwards Pericardial (C-Ep) whose tissue annulus diameter was 27 mm. The experimental instrument similar to that of Umezu et al. was prepared to determine the mean pressure gradient, output and calculated orifice area of each valve. At the same time, a recently-manufactured valve attachment head was employed to measure the output, pressure gradient and orifice area by altering the valve attachment angle and orientation and increasing the number of heart beats from 60 bpm to 160 bpm, and the following results were obtained: With the changeable angle valve, an angle was determined whose end was parallel to the flow path in association with changes in the attachment angle, and the orientation was such that the pressure gradient was reduced and the orifice area was increased.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Prosthetic valve replacement in children

Between 1975 and 1998, 27 patients aged 3 months to 14 years underwent replacement of the aortic, mitral, tricuspid, and pulmonary valves. Five different types of prosthetic valves were used; three were mechanical valves and two were bioprosthetic valves. There were 3 hospital deaths. Among the 24 survivors there were 4 late deaths. Arrhythmia requiring pacemaker implantation occurred in 2 cases after AVR and TVR. Thromboembolic events occurred in 3 patients, all with mechanical valves in pulmonary position. Infective endocarditis occurred in 1 patient after PVR with a mechanical valve. No bleeding complication occurred among the patients on a regimen of Coumadin and Dipyridamole. Two patients, both with Hancock bioprosthesis, required a second valve replacement on account of severely calcified changes. Mechanical valves in left side heart had a satisfactory long-term performance. One patient who had undergone MVR for congenital parachute mitral valve received reoperation for growth. A larger sized prosthetic valve should be used at the first replacement, and special procedures including supra-annular positioning or annular augmentation are recommended for MVR or AVR respectively.     

Intravascular haemolysis after valve replacement: comparative study between Starr-Edwards (ball valve) and Björk-Shiley (disc valve) prosthesis.

Seventy-four patients with single prosthetic valves (Björk-Shiley or Starr-Edwards) in the mitral or aortic position and 18 controls with rheumatic valvar heart disease were investigated for evidence of intravascular haemolysis. Serum lactate dehydrogenase (LDH) was used as the most sensitive indicator of haemolysis. Raised concentrations were found in a third of 39 patients with Björk-Shiley prostheses (mean 281 IU/l) and in all 35 patients with Starr-Edwards prostheses (mean 859 IU/l. Values were considerably higher in patients with Starr-Edwards prostheses and particularly in those with aortic prostheses (mean 927 IU/l). Eight out of 12 patients with haemosiderinuria had Starr-Edwards valves. Intravascular haemolysis was of little clinical significance in patients with Björk-Shiley prostheses, but some patients with Starr-Edwards prostheses became iron deficient as a result.