Late Evaluation of Patients Undergoing Valve Replacement with the Björk-Shiley Prosthesis

This study analyzes 484 patients who survived mitral, aortic, or mitral and aortic valve replacement using the Björk-Shiley prosthesis from January, 1970, through December 31, 1974. Long-term follow-up of 1½ to 6½ years (mean, 3.67 yr) was done on 435 patients (98.2%).Eighty to 85% of the patients have improved noticeably. Thromboembolic problems occurred in 6.9%, representing 1.5 emboli per 1,000 patient-months. Anticoagulant bleeding problems occurred in 6.4% of the patients; late mortality was 15%.Actuarial survival curves showed patients at risk to 6 years having a 79% chance of survival. The same analysis according to preoperative New York Heart Association Functional Classification showed a striking reduction in survival in Class IV patients. The Björk-Shiley prosthesis is a good choice for valve replacement today. Earlier diagnosis and treatment are needed to obtain better long-term survival.     

Early Results of Valve Replacement with the Björk-Shiley Convexoconcave Prosthesis

The Björk-Shiley convexoconcave prosthetic valve has design characteristics that may result in a lower incidence of thromboembolic complications than the conventional spherical Björk-Shiley prosthesis. We evaluated the results of valve replacement with the convexoconcave prosthesis in 248 patients receiving 301 prosthetic valves between March, 1979, and June, 1981. One hundred thirteen patients had aortic valve replacement (AVR), 73 had mitral valve replacement (MVR), and 62 had multiple valve replacement. Two hundred nine (84%) were in New York Heart Association Class III or IV. The median duration of follow-up was 13 months, and follow-up information was available for 246 (99%) of the patients. The actuarial incidence of freedom from thromboembolism at two years was 98% in the AVR group, 97% in the MVR group, and 87% in the group having multiple valve replacement. There were no documented episodes of valve thrombosis or mechanical failure and no fatal thromboembolic complications. The absence of valve thrombosis is in marked contrast to the results reported with the spherical disc valve. Although longer follow-up is necessary, it appears that the convexoconcave design represents a major improvement in the Björk-Shiley prosthesis.     

Strut Fracture and Disc Embolization in Björk-Shiley Mitral Valve Prostheses: Diagnosis and Management

Mechanical failure of the Björk-Shiley tilting disc prosthesis is a rare but catastrophic complication of the valve. Several previously reported cases of major strut fracture with disc embolization led to improvements in the structure of the prosthesis. A case of minor strut fracture in the improved convexoconcave model of the Björk-Shiley mitral valve prosthesis is described. The literature on mechanical failures in the Björk-Shiley mitral valve prosthesis is reviewed, and recommendations for recognition and management of this problem are made.     

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.     

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.     

Ten-Year Follow-up in Aortic Valve Replacement Using the Björk-Shiley Prosthesis

An in-depth statistical analysis of early and late results of aortic valve replacement using the Björk-Shiley tilting-disc prosthesis is presented. Our experience with this prosthesis indicates that replacement carries a low surgical risk, a low incidence of complications (embolization, infection, or hemorrhage due to long-term use of anticoagulants), and good long-term survival.Coexisting coronary artery disease increases surgical mortality significantly, and simultaneous, complete revascularization is essential. Patients undergoing isolated aortic valve replacement did significantly better than those requiring other simultaneous procedures or those who had had previous operations.Earlier operation is imperative since progress of aortic valve disease is unpredictable by duration of symptoms, and patients in New York Heart Association Functional Class II have a low surgical risk and a greatly increased survival. It would appear from this study that additional criteria, such as increasing ventricular dilatation and hypertrophy determined by echocardiographic studies and gated nuclear studies showing deterioration of ejection fraction on exercise, should be used to help determine time of surgical intervention rather than symptomatology alone.     

Early Postoperative Development of Aortic Regurgitation Related to Pannus Ingrowth Causing Incomplete Disc Seating of a Björk-Shiley Prosthesis

Incomplete seating of the disc of a recently implanted Björk-Shiley aortic prosthesis occurred because of excessive ingrowth of fibrous tissue. This resulted in significant aortic regurgitation plus hemolytic anemia. Reoperation with identification of the problem and implantation of a Hancock bioprosthesis was required for resolution of the situation.     

Heart valve replacement with the Bj?rk-Shiley Monostrut valve: early results of a multicenter clinical investigation

To evaluate the clinical performance of the Bj?rk-Shiley Monostrut prosthesis, five centers combined their early experience. Between May, 1982, and June, 1985, 537 prostheses were implanted in 486 patients at these centers: 246 patients had aortic valve replacement (AVR), 163 underwent mitral valve replacement (MVR), and 47 had double-valve replacement (DVR). Thirty patients underwent other, more complex procedures. Concomitant cardiac procedures were performed in altogether 25%. Overall hospital (30 days) mortality was 5.1% (3.6% for AVR, 4.3% for MVR, 8.3% for DVR, and 16.6% for other procedures). The patients were followed up at 6- to 9-month intervals from 6 to 48 months (mean follow-up, 33 months). Follow-up was 99.6% complete. Late mortality was 7.2%. The three-year survival rate was 91.0% for AVR, 92.3% for MVR, and 76.2% for DVR. There was no structural failure of the prosthesis. No instances of valve thrombosis and fatal thromboembolism occurred in anticoagulated patients. The three-year incidence of freedom from thromboembolic events (including TIA) was 89.8% for AVR, 94.9% for MVR, and 90.2% for DVR. Preoperative and postoperative data for the assessment of mechanical hemolysis was available in 60% of the patients. The degree of mechanical hemolysis was low and did not change with time. Although the follow-up is still short, the Bj?rk-Shiley Monostrut prosthesis appears to represent an improvement over previous Bj?rk-Shiley models, particularly with regard to durability.     

Aortic Valve Replacement in Preteenage Children

During the last 15 years, 26 children who ranged from 4 to 12 years old underwent sub-coronary aortic valve replacement (AVR) at the Texas Heart Institute. The valve lesions resulted from congenital heart disease in 20 patients, 15 of whom had had a previous operation including 13 aortic valve procedures. Cystic medial necrosis necessitated AVR in 5 patients, all of whom had physical findings of Marfan's syndrome. One patient had rheumatic heart disease and required double-valve (aortic and mitral) replacement. Six different types of prosthesis were used: the Smeloff-Cutter, Starr-Edwards, Cooley-Cutter, Hancock porcine, Ionescu-Shiley, and Björk-Shiley.The first patient in the series was the only early death (3.8%). Long-term follow-up data ranging from 1 month to 10 years were available on 20 patients. Three late deaths occurred (11.5%). All survivors are doing well and have good exercise tolerance. These data suggest that AVR performed in childhood is a safe, durable, and well-tolerated form of therapy. Later replacement, if necessary, can be accomplished with larger-sized prostheses. Our present choice is the Ionescu-Shiley bovine xenograft because of its superior hemodynamic characteristics and low incidence of embolic complications.     

Rifampin in the Management of Early Prosthetic Staphylococcus epidermidis Endocarditis

Staphylococcus epidermidis endocarditis occurred four days following aortic valve replacement with a Björk-Shiley prosthesis. Antimicrobial therapy, shown to be effective by in vitro and in vivo studies, failed to eradicate the infection. When rifampin was added to the existing antibiotic regimen, peak serum bactericidal activity increased, the patient defervesced, and blood cultures became negative.     

Long-Term Results of Cardiac Valve Replacement with the Delrin-Disc Model of the Björk-Shiley Valve Prosthesis

One hundred two Björk-Shiley valve prostheses with the Delrin-disc occluder were implanted in 83 patients between January, 1971, and July, 1972. Fifty-eight were in the mitral position, 42 in the aortic, and 2 in the tricuspid. Complete follow-up until 1981 was obtained in 93% of the patients (mean follow-up, 66.8 months). Hospital mortality was 18% and late mortality, 19%. Survival according to actuarial methods was 84.8% at 5 years and 78.1% at 9 years after operation. Thromboembolism was detected in 8.8% of patients but caused no deaths. The incidence was 1.2% and 1.5% per year in those patients treated with Coumadin and antiplatelet agents, respectively. Reoperation was necessary in 13% of the patients.Most survivors (72%) are in New York Heart Association Functional Class I, despite a preoperative status of Class III or IV in 57% of the patients. Hospital mortality may be due to poorer understanding of patient management and less refined techniques of myocardial protection. Long-term survival with this prosthesis is similar to that in more recent studies, and rates of thromboembolism and malfunction compare favorably with other prosthetic valves.     

Extrinsic Obstruction of the Björk-Shiley Valve in the Mitral Position

Four recently seen patients with acute, extrinsic obstruction of a Björk-Shiley prosthesis in the mitral position are described. In 2 of them, the disc occluder was stuck in the closed position by a strand of chordal tissue, which was compressed between the disc edge and valve rim. In another patient, sticking of the disc by a similar mechanism was caused by a suture that migrated into the valve orifice. Intermittent malfunction of the valve in the fourth patient was related to interference with valve opening by ventricular myocardium and occurred when the patient lay on his right side. The mechanisms of extrinsic obstruction of the Björk-Shiley valve and their recognition, treatment, and prevention are discussed.     

Thrombotic Obstruction of the Björk-Shiley Aortic Valve Prosthesis. Report of Four Cases

We present four cases of late thrombotic obstruction of the Björk-Shiley aortic valve prosthesis. The incidence of this complication reported in the literature to vary from 0.7% to 5%. In our experience of a total of 623 Björk-Shiley aortic valve replacements, we observed this complication in only 4 patients (0.6%). Two of them had poorly controlled anticoagulation therapy. The clinical presentation was subacute in all four patients. Surgical treatment, thrombectomy and debridement, was performed in all of them. The diagnosis was made upon abrupt and progressive onset of dyspnoea, physical examination data and echocardiographic and radioscopic findings. Angiocardiographic studies were needed in two patients.     

Valve replacement in children under twenty years of age. Experience with the Bj?rk-Shiley prosthesis

Prosthetic valve replacement in young patients has been reported to be associated with a high mortality and morbidity because of valve-related problems. Of 549 patients undergoing valve replacement with the Bj?rk-Shiley valve prosthesis, 136 were under the age of 20 years. Sixty-four patients were under 16 years of age, the youngest being 6 years old. Of the 136 patients, 61 underwent mitral valve replacement, 50 received an aortic valve, and 25 received both aortic and mitral valves. Overall operative mortality was 10.3%. Late mortality over a follow-up period of 6 months to 8 years was 4.4%. Actuarial survival curves up to 8 years of follow-up are presented. Results obtained in this group are compared with those obtained in 413 patients over 20 years of age operated during the same period. Valve thrombosis was not seen in any patient under 20 years of age, but it occurred in 4.13% of the patients over 20 years of age. The incidence of thromboembolism and anticoagulant-related hemorrhage was very low. There has been no instance of structural failure of the valve. Long-term results are excellent, with 90% of the survivors returning to New York Heart Association Functional Class I. The Bj?rk-Shiley valve gives excellent and durable long-term palliation in young patients requiring valve replacement.     

Hemodynamic Evaluation of the Integral Monostrut Björk-Shiley Prosthesis in the Aortic Position

Between May, 1983, and November, 1984, the new integral monostrut Björk-Shiley prosthesis was used for aortic valve replacement in 62 patients. The prosthesis is machined from a solid piece of cobalt alloy and has no welded joints. The traditional U-shaped outlet strut has been replaced by a projecting metal finger that holds the disc in place. The disc opens to 70 degrees and is convexoconcave.Successful transseptal heart catheterization was performed in 23 patients an average of 6 months following operation to evaluate the hemodynamic performance of the prosthesis. The mean peak-to-peak gradient was 7.73 ± 7.49 mm Hg (± standard deviation). In five valves it was 0, and in only three was it higher than 15 mm Hg. Significant peak gradients were directly related to the valve index (valve area/body surface area). Mean systolic gradient at rest was 12.7 ± 6.27 mm Hg and did not increase after exercise. Effective orifice areas were adequate, and the discharge coefficient ranged from 0.77 for the 21-mm prosthesis to 0.48 for the 29-mm prosthesis. Minimal regurgitation, which was washed out on the next systole, was observed with all sizes of the prosthesis. Disc opening was maximal (70 degrees) in all but one of the observed instances.Longer clinical follow-up is required, but the new integral monostrut Björk-Shiley prosthesis, with its important design changes and excellent hemodynamic performance, appears to be a promising aortic valve substitute.     

Clinical and Hemodynamic Evaluation of the 19 mm Björk-Shiley Aortic Valve Prosthesis

Between November, 1973, and March, 1980, 43 patients underwent isolated aortic valve replacement with 19 mm Björk-Shiley prostheses at the Johns Hopkins Hospital. There were 4 male and 39 female patients ranging from 12 to 75 years old (mean, 54.5 years). Average weight was 62 ± 2 kg and average body surface area, 1.64 ± 0.3 m². Five patients died within thirty days of operation; however, since 1975, hospital mortality has been 5.9%. The 38 survivors have been followed up for as long as 85 months (mean, 40 months). There were 4 late deaths, and actuarial survival in patients discharged from the hospital was 81% at five years. All long-term survivors were in New York Heart Association Functional Class I (29 patients) or Class II (5 patients). Preoperative and postoperative echocardiograms in 17 patients demonstrated significant decreases in mean left ventricular wall thickness (12.9 ± 1.8 mm vs 10.3 ± 1.4 mm; p < 0.001) and in left ventricular mass (262 ± 95 gm vs 188 ± 50 gm; p < 0.02).Postoperative cardiac catheterization data were obtained from an additional 24 patients undergoing aortic valve replacement with the 19 mm Björk-Shiley prosthesis at the National Heart Institute. Average peak systolic gradient at rest was 16 mm Hg (range, 0 to 45 mm Hg) and was found to be directly related to body surface area (r = 0.60, p < 0.002). Average effective valve orifice area was 1.06 cm² (range, 0.63 to 2.02 cm²).For patients with small aortic roots, aortic valve replacement with the 19 mm Björk-Shiley valve is a satisfactory and, perhaps, preferable alternative to aortic annuloplasty to accommodate larger sized prostheses.     

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.     

Fifty-two Consecutive Aortic Valve Replacements Employing Local Deep Hypothermia

From August, 1972, to May, 1974, 52 consecutive aortic valves were replaced with the Björk-Shiley tilting-disc prosthesis. The hospital mortality was zero. Patients ranged in age from 14 to 77 years, and 19 patients had simultaneous correction of associated cardiac lesions. Using techniques of low flow and local deep hypothermia, aortic valve replacement can be accomplished with little risk even in patients with associated coronary arteriosclerosis. Coronary artery perfusion is unnecessary and often hazardous. Follow-up periods vary from one to twenty-one months. Forty-nine patients are alive and substantially improved.     

A case of strut fracture of the new Björk-Shiley mital valve prosthesis

We treated a 61-year-old Japanese man with a strut fracture of the new Björk-Shiley mitral valve. This fracture occurred about two months after mitral valve replacement. Emergency reoperation was performed as soon as the chest X-ray showed the fracture, despite the presence of cardiopulmonary shock. He died on the 3rd postoperative day. Similar reported cases of literature are reviewed.     

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.