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Survival following fracture of strut from mitral prosthesis with disc translocation
Survival following fracture of strut from mitral prosthesis with disc translocation Mechanical complications ofprosthetic valves are increasingly rare. The acute, catastrophic nature of the symptoms associated with massive transvalvular regurgitation preclude sU/Ti\'(/1 except with immediate operation. In the patient described herein, two weld fractures of a Bjork-Shiley mitral prosthetic strut led to displacement of the \'(/11'1' occluder into the leji atrium. The patient survived reoperation, following which the strut was detected radiologically in the left ventricular free wall. A .1'1011', limited recoverv resulted from his 5 preoperative hours cf deep shock and ('(}II/(/, No complication attributable to the retained ventricular foreign body has been identified.
M. Terry McEnany, M.D., Edwin O. Wheeler, M.D., and W. Gerald Austen, M.D., Boston, Mass., and Providence, R. I.
T
he Bjork-Shiley prosthesis has been proved effective in the surgical treatment of mitral valvular disease. I Its unique characteristics of low profile and freedom from obstruction have made it the prosthetic valve of choice for many surgeons. As with all artificial cardiac valves, there is an inherent thromboembolic complication rate and frequency of infection and paravalvular leak. 2,3 However, the prosthesis has been relatively free of the nonthrombotic mechanical complications that have been seen in many other ball or disc occluder prostheses. Bjork:' has noted interference with disc closure by the ventricular myocardium, but this may be avoided by correct orientation of the ring orifice. Jones and associates.'; described restriction of the disc occluder by valve sutures entangled on the ventricular aspect of the valve. Messmer's group" observed disc dislodgment 18 hours after insertion of a Delrin-disc Bjork-Shiley prosthesis, felt to be the result of two simultaneous misadventures: (I) Delrin disc distortion secondary to steam autoclaving and (2) distortion of the containing strut by twisting the seated valve with a clamp. These two occurrences have been minimized by substitution of hard pyrolitic carbon for the softer DelFrom the Departments of Surgery and Medicine. Harvard Medical School, Boston, Mass.; The Massachusetts General Hospital. Boston, Mass.: and the Department of Surgery. Brown University School of Medicine and The Miriam Hospital. Providence. R, I.
Received for publication Dec. 6. 1978, Accepted for publication March 20. 1979. Address for reprints: M. Terry McEnany. M,D., Department of Surgery. The Miriam Hospital. Providence. R. I. 02906,
136
rin occluder and vigorous education of surgeons to use the valve holder for any postinsertion changes in orientation. In 1977, Norenberg and associates 7 reported the only instance of fracture of a pyrolitic carbon disc, which occurred 7 months after insertion of the prosthetic valve. There have been no previous reports of strut fracture in the Bjork-Shiley prosthesis, although this complication has been previously noted in De Bakey, H Beall." and Cooley-Cutter prosthetic valves, 10
Case report A 25-year-old carpenter (MGH No, 1955622) was first admitted to the Massachusetts General Hospital in October. 1974, with a 2 year history of increasing dyspnea, fatigability, paroxysmal nocturnal dyspnea, and palpitations, He had a long history of a murmur following rheumatic fever. Physical examination revealed auscultatory evidence of mitral stenosis and aortic stenosis and regurgitation, The electrocardiogram demonstrated sinus rhythm with left atrial enlargement. and the chest x-ray film showed left atrial enlargement. Cardiac catheterization proved tight mitral stenosis. I + mitral regurgitation. 2+ mitral valvular calcification. and I + aortic regurgitation, The mitral valve was replaced with a 29 mm. Bjork-Shiley prosthesis, At the time of operation. the patient's left ventricle was markedly hypertrophied and the cavity was very small. The mitral valve ring was small. as was the aortic anulus, which would admit only the tip of the index finger. The aorta was noted to be only half the normal diameter. and the aortic regurgitation was mild. Postoperatively. the patient did well and was discharged on the ninth postoperative day. One month later. however. he noted chills. fever. and intermittent joint pains, The patient was readmitted to the hospital 6 weeks after the mitral valve replacement following a shaking chill with temperatures to 102° F, At the time of readmission. the heart did not appear enlarged, the prosthetic
0022-5223/79/070136+04$00.40/0 © 1979 The C. V, Mosby Co.
Volume 78 Number 1 july, 1979
Fracture of mitral prosthetic strut
137
Fig. 1. View of the atrial side of the fractured Bjork-Shiley mitral valve demonstrating the clean separation of the atrial (upstream) strut from the metal valve seat. sounds were crisp. and there was a Grade 2/6 rough aortic ejection murmur and a Grade 2/6 aortic diastolic blowing murmur. There was no separate mitral valvular murmur, The lungs were clear. the liver and spleen could not be felt. and there were no petechiae, In the hospital. arthralgias and splinter hemorrhages developed and the spleen became palpable, Multiple blood cultures were positive for diphtheroids. and the patient was begun on a regimen of penicillin and gentamicin, At that time. an apical systolic murmur became audible, He quickly became afebrile, and there were no symptoms of congestive failure. The cardiac silhouette did not change. Multiple cineftuoroscopic evaluations of the prosthesis did not reveal any unusual motion. Intravenous antibiotics were continued for 6 weeks, and the patient was discharged receiving digoxin and Coumadin. Following discharge, the patient noted a rapid increase in dyspnea and orthopnea. The symptoms improved somewhat with diuretic and salt restriction therapy, but they recurred. Therefore. he was admitted again in February, 1975. Cardiac catheterization revealed left ventricular failure. severe mitral regurgitation. and mild-to-moderate aortic regurgitation. In March. 1975. the patient was returned to the operating room. where a large paravalvular leak was found. Approximately 35 percent of the circumference of the mitral anulus was markedly distorted by healed vegetations, from which all sutures had tom free. Because of the increased aortic regurgitation. the aortic valve was also exposed and the three fused commissures of the valve were incised. Heavy calcifications were debrided from the left and noncoronary cusps. to produce a watertight, nonregurgitant valve. Another No. 29 Bjork-Shiley mitral prosthesis was then sutured in place in the same orientation as the first valve (major orifice anterior), without any postplacement reorientation of the valve seat. There was no bacterial growth from any of the tissue removed at the time of the operation. The patient's postoperative course was uneventful, and he was discharged on the thirteenth postoperative day receiving Coumadin only. When
Fig. 2. Anteroposterior chest roentgenogram obtained I year following removal of the fractured prosthesis. The metal strut is visible overlying the left ventricular silhouette. seen 6 weeks postoperatively, he was asymptomatic. Examination revealed no cardiomegaly, a Grade 1/6 systolic ejection murmur, and a short Grade 2/6 early diastolic blow along the left sternal border. The patient continued to do well for approximately 10 weeks, at which time catastrophic pulmonary edema suddenly developed. He was taken to his local hospital, unresponsive and pulseless. A pressor amine infusion was started. and the patient was transferred by ambulance to the Massachusetts General Hospital. 4 hours distant. Upon arrival, the patient was comatose, with an unobtainable blood pressure. The pupils were dilated but responsive. He was immediately intubated, taken to the operating room, and placed on cardiopulmonary bypass by means of groin cannulation. The heart was exposed, and when the left atrium was opened, the pyrolite disc was found in the left atrium. The larger (upstream) strut of the Bjork-Shiley prosthesis was missing and could not be found by thorough examination of the atrium and ventricle (Fig. I). There was no paravalvular leak and only trace aortic regurgitation. The fractured prosthesis was replaced with a 29 mm. Hancock xenograft valve, and the patient was separated from cardiopulmonary bypass with only modest difficulty. The missing strut was noted in the left ventricle on the postoperative chest roentgenograms (Fig. 2). Severe neurologic symptoms persisted postoperatively, thought to be secondary to the long period of preoperative anoxia and shock. The patient's rehabilitation was slow, but he ultimately was discharged from the hospital 6 weeks postoperatively. He has
The Journal of
I 38
McEnany, Wheeler, Austen
progressed minimally over the ensuing 3 years and has had one episode of subacute bacterial endocarditis in 1976, for which he was treated with intravenous antibiotics only. During this episode, the murmur of aortic regurgitation became strikingly louder. When seen 3 years following the last valve replacement, the blood pressure was 170/30 and signs of moderate left ventricular failure were present.
Discussion The Bjork-Shiley prosthesis has been remarkably free of nonthrombotic mechanical complications, especially after the introduction of the pyrolitic carbon occluder. There have been isolated reports of disc fracture? and sticking of the occluder in the closed position.!' Embolization of a Bjork-Shiley Delrin mitral disc has been reported, associated with autoclave disc distortion and possible deformation of a strut. 6 Strut abnormalities also have led to migration of a BjorkShiley aortic disc, 12 but no previous Bjork-Shiley strut fracture has been reported. The fractured strut of the patient in this report remains embedded in the left ventricular myocardium, and it has been impossible to discern whether there was an inherent structural abnormality associated with its fracturing (Fig. 2). Close examination of the residual valve components by Shiley Laboratories revealed no evident mechanical variance in the materials of the prosthesis. * Temporally closely associated with this experience were two other strut fractures in 29 mm. Bjork-Shiley mitral prostheses.t No subsequent incidents have been reported. Consideration has been given to the possible etiologic relationship of any mechanical twisting of the metal valve apparatus inside the sewing ring for perfect postimplantation orifice alignment. This was unnecessary in our patient, as orientation identical to that of the first (removed) Bjork-Shiley prosthesis was guaranteed before the valve was sewn into the anulus. Of interest in this patient is the retrograde embolization of the disc. Most of the other embolized discs have been found in the abdominal aorta. The missing strut was the upstream (atrial) strut, which would have been fractured ultimately by the force of the disc's closing in ventricular systole (Fig. I). Absence of the strut implies simultaneous fracture of both welds joining the strut to the circular metal seat of the valve. Fracture of only one of the welds most likely would have led to bending of the strut and escape of the disc. Once the disc had escaped, there no longer would be any pressure or tension on the strut, which should, therefore, remain attached to the seat by the one remaining weld.
* Personal
communication from Shiley Laboratories, September.
1975. tPersonal communication from Shiley Laboratories. July. 1975.
Thoracic and Cardiovascular Surgery
The explosive nature of the simultaneous weld disruptions probably carried the occluder and the strut into the left atrium. From there the strut migrated to the left ventricle, whereupon it became embedded in the trabeculae carnae and was not detectable through the atriotomy at the ti me of the third mitral valve replacement. There have been no identifiable complications of the ventricular foreign body. Catastrophic acute mitral regurgitation from prosthetic malfunction is a recognized lethal complication of mitral valve replacement. Successful treatment relies upon immediate reoperation and replacement of the errant valve. Survivors have been reported following reoperation up to 16 hours following acute onset of the symptoms of pulmonary edema secondary to disc migration."?: ia. H All authors agree, however, that the patient should be operated upon immediately when the diagnosis of valve dysfunction is made and that the diagnosis must be made clinically, for the time required for cardiac catheterization usually constitutes a lethal delay. The recent insertion of a radiopaque ring into the disc during manufacture has made it easier to ascertain disc presence in correct relationship to the struts and metal seat of the valve. This information will also be helpful in making correct early diagnosis in those patients with acute thrombotic obstruction of the BjorkShiley valve, which, like all disc valves, may have the propensity to occluder entrapment, especially in patients not receiving adequate anticoagulation. I;; Increased experience and familiarity with the normal echocardiographic patterns of the various valve prostheses may help in the triage of a patient in whom the diagnosis is not certain. 16. Ii However, time should not be taken from the rapid transport of such a patient to the operating room for even these simple studies if the constellation of ( I) previous prosthetic val ve replacement, (2) acute onset of pulmonary edema and cardiogenic shock, and (3) absence of prosthetic sounds is present. The patient in this report did not have a chest roentgenogram prior to transfer to the operating room, which was initiated as soon as the surgeon was notified of his presenting symptoms. The preoperative diagnosis was disruption of the sewing ring secondary to recurrent prosthetic endocarditis. The symptoms, however, mandated immediate valve replacement in this comatose patient. The problem of acute prosthetic valve failure is uncommon and, most assuredly, will become even less frequent with the increasing use of biological prostheses, which fail much more gradually. Immediate operation remains the only rational approach to the patient with massive prosthetic dysfunction.
Volume 78
Fracture of mitral prosthetic strut
Number 1
1 39
July, 1979
REFERENCES Book K: Mitral valve replacement with the Bjork-Shiley tilting disc valve. Scand 1 Thorne Cardiovasc Surg 8: Suppl 12:1-28. 1974 2 Henze A. Fortune RL: Regurgitation and haernolysis in artificial heart valves. Scand 1 Thorne Cardiovasc Surg
II
12
8:167-175. 1974 3 Maroiias 1M. Rufilanchas 11. Yillagra F. Juffe A. Miranda AL. Iglesias A. Figuera D: Isolated mitral valve replacement with the Bjork-Shiley prosthesis in 100 consecutive patients. Short and long-term results. 1 Car-
13
diovasc Surg 18:575-581. 1977 -I Bjork YO: The central flow tilting disc valve prosthesis
5
6
7
8
9
(Bjork-Shiley) for mitral valve replacement. Scand 1 Thorac Cardiovasc Surg 4:15-23. 1970 Jones AA. Otis lB. Fletcher GF. Roberts WC: A hitherto undescribed cause of prosthetic mitral valve obstruction. 1 THORAC CAROIOVASC SURG 74:116-117. 1977 Messmer B1. Rothlin M. Senning A: Early disc dislodgment. An unusual complication after insertion of a Bjork-Shiley mitral valve prosthesis. 1 THORAC CARDIOVASC SLRG 65:386-390. 1973 Norenberg DD, Evans EW. Gundersen AE. Abellera RM; Fracture and embolization of a Bjork-Shiley disc. 1 THORAC CARDIOVASC SLRG 74:925-927, 1977 Zumbro GL. Cundy PE lr. Fishback ME, Galloway RF: Strut fracture in De Bakcy valve. 1 THORAC CAROIOVASC SURG 74:469-470, 1977 Nathan Ml: Strut fracture. A late complication of Beall mitral valve replacements. Ann Thorac Surg 16:610-
613, 1975 10 Ansbro 1. Clark R, Gerbode F: Successful surgical cor-
14
15
rection of an ernbolized prosthetic valve poppet. 1 THORAC CARDIOVASC SURG 72: 130-132, 1976 Saunders CR, Rossi NP, Rittenhouse EA: Failure of a Bjork-Shiley mitral valve prosthesis to open. Clinical recognition. 1 Cardiovasc Surg 18:571-574, 1977 Mulder GA: Discussion of Bjork YO, Henze A, Holmgren A: Five years' experience with the BjorkShiley tilting disc valve in isolated aortic valvular disease. 1 THORAC CARDIOVASC SURG 68:393-404, 1974 Roberts AK, Lambert Cl, Mitchel BF: Embolization of disc occluder of a Wada-Cutter mitral prosthesis with survival. Ann Thorac Surg 21:361-364, 1976 Gelfand ET, Callaghan lC, Taylor RF: Survival after late disc dislodgment of a mitral Wada-Cutter prosthesis. Can 1 Surg 21:248, 1978 Moreno-Cabral RJ, McNamara 11, Marniya RT, Brainard Sc. Chung GKT: Acute thrombotic obstruction with Bjork-Shiley valves. 1 THORAC CARDIOVASC SURG 75:
321-330, 1978 16 Douglas lE, Williams GD: Echocardiographic evaluation of the Bjork-Shiley prosthetic valve. Circulation SO: 52-57, 1974 17 Srivastava TN, Hussain M, Gray LA Jr, Flowers NC: Echocardiographic diagnosis of a stuck Bjork-Shiley aortic valve prosthesis. Chest 70:94-98, 1976 18 Boe BB, Fishman NH, Hutchinson lC, Goodenough SH: Occluder disruption of Wada-Cutter valve prosthesis. Ann Thorac Surg 20:256-264, 1975 19 Hughes DA, Leatherman LL, Norman rc, Cooley DA: Late embolization of prosthetic mitral valve occluder with survival following reoperation. Ann Thorac Surg 19:
212-215, 1975
M. Terry McEnany, M.D., Edwin O. Wheeler, M.D., and W. Gerald Austen, M.D., Boston, Mass., and Providence, R. I.
T
he Bjork-Shiley prosthesis has been proved effective in the surgical treatment of mitral valvular disease. I Its unique characteristics of low profile and freedom from obstruction have made it the prosthetic valve of choice for many surgeons. As with all artificial cardiac valves, there is an inherent thromboembolic complication rate and frequency of infection and paravalvular leak. 2,3 However, the prosthesis has been relatively free of the nonthrombotic mechanical complications that have been seen in many other ball or disc occluder prostheses. Bjork:' has noted interference with disc closure by the ventricular myocardium, but this may be avoided by correct orientation of the ring orifice. Jones and associates.'; described restriction of the disc occluder by valve sutures entangled on the ventricular aspect of the valve. Messmer's group" observed disc dislodgment 18 hours after insertion of a Delrin-disc Bjork-Shiley prosthesis, felt to be the result of two simultaneous misadventures: (I) Delrin disc distortion secondary to steam autoclaving and (2) distortion of the containing strut by twisting the seated valve with a clamp. These two occurrences have been minimized by substitution of hard pyrolitic carbon for the softer DelFrom the Departments of Surgery and Medicine. Harvard Medical School, Boston, Mass.; The Massachusetts General Hospital. Boston, Mass.: and the Department of Surgery. Brown University School of Medicine and The Miriam Hospital. Providence. R, I.
Received for publication Dec. 6. 1978, Accepted for publication March 20. 1979. Address for reprints: M. Terry McEnany. M,D., Department of Surgery. The Miriam Hospital. Providence. R. I. 02906,
136
rin occluder and vigorous education of surgeons to use the valve holder for any postinsertion changes in orientation. In 1977, Norenberg and associates 7 reported the only instance of fracture of a pyrolitic carbon disc, which occurred 7 months after insertion of the prosthetic valve. There have been no previous reports of strut fracture in the Bjork-Shiley prosthesis, although this complication has been previously noted in De Bakey, H Beall." and Cooley-Cutter prosthetic valves, 10
Case report A 25-year-old carpenter (MGH No, 1955622) was first admitted to the Massachusetts General Hospital in October. 1974, with a 2 year history of increasing dyspnea, fatigability, paroxysmal nocturnal dyspnea, and palpitations, He had a long history of a murmur following rheumatic fever. Physical examination revealed auscultatory evidence of mitral stenosis and aortic stenosis and regurgitation, The electrocardiogram demonstrated sinus rhythm with left atrial enlargement. and the chest x-ray film showed left atrial enlargement. Cardiac catheterization proved tight mitral stenosis. I + mitral regurgitation. 2+ mitral valvular calcification. and I + aortic regurgitation, The mitral valve was replaced with a 29 mm. Bjork-Shiley prosthesis, At the time of operation. the patient's left ventricle was markedly hypertrophied and the cavity was very small. The mitral valve ring was small. as was the aortic anulus, which would admit only the tip of the index finger. The aorta was noted to be only half the normal diameter. and the aortic regurgitation was mild. Postoperatively. the patient did well and was discharged on the ninth postoperative day. One month later. however. he noted chills. fever. and intermittent joint pains, The patient was readmitted to the hospital 6 weeks after the mitral valve replacement following a shaking chill with temperatures to 102° F, At the time of readmission. the heart did not appear enlarged, the prosthetic
0022-5223/79/070136+04$00.40/0 © 1979 The C. V, Mosby Co.
Volume 78 Number 1 july, 1979
Fracture of mitral prosthetic strut
137
Fig. 1. View of the atrial side of the fractured Bjork-Shiley mitral valve demonstrating the clean separation of the atrial (upstream) strut from the metal valve seat. sounds were crisp. and there was a Grade 2/6 rough aortic ejection murmur and a Grade 2/6 aortic diastolic blowing murmur. There was no separate mitral valvular murmur, The lungs were clear. the liver and spleen could not be felt. and there were no petechiae, In the hospital. arthralgias and splinter hemorrhages developed and the spleen became palpable, Multiple blood cultures were positive for diphtheroids. and the patient was begun on a regimen of penicillin and gentamicin, At that time. an apical systolic murmur became audible, He quickly became afebrile, and there were no symptoms of congestive failure. The cardiac silhouette did not change. Multiple cineftuoroscopic evaluations of the prosthesis did not reveal any unusual motion. Intravenous antibiotics were continued for 6 weeks, and the patient was discharged receiving digoxin and Coumadin. Following discharge, the patient noted a rapid increase in dyspnea and orthopnea. The symptoms improved somewhat with diuretic and salt restriction therapy, but they recurred. Therefore. he was admitted again in February, 1975. Cardiac catheterization revealed left ventricular failure. severe mitral regurgitation. and mild-to-moderate aortic regurgitation. In March. 1975. the patient was returned to the operating room. where a large paravalvular leak was found. Approximately 35 percent of the circumference of the mitral anulus was markedly distorted by healed vegetations, from which all sutures had tom free. Because of the increased aortic regurgitation. the aortic valve was also exposed and the three fused commissures of the valve were incised. Heavy calcifications were debrided from the left and noncoronary cusps. to produce a watertight, nonregurgitant valve. Another No. 29 Bjork-Shiley mitral prosthesis was then sutured in place in the same orientation as the first valve (major orifice anterior), without any postplacement reorientation of the valve seat. There was no bacterial growth from any of the tissue removed at the time of the operation. The patient's postoperative course was uneventful, and he was discharged on the thirteenth postoperative day receiving Coumadin only. When
Fig. 2. Anteroposterior chest roentgenogram obtained I year following removal of the fractured prosthesis. The metal strut is visible overlying the left ventricular silhouette. seen 6 weeks postoperatively, he was asymptomatic. Examination revealed no cardiomegaly, a Grade 1/6 systolic ejection murmur, and a short Grade 2/6 early diastolic blow along the left sternal border. The patient continued to do well for approximately 10 weeks, at which time catastrophic pulmonary edema suddenly developed. He was taken to his local hospital, unresponsive and pulseless. A pressor amine infusion was started. and the patient was transferred by ambulance to the Massachusetts General Hospital. 4 hours distant. Upon arrival, the patient was comatose, with an unobtainable blood pressure. The pupils were dilated but responsive. He was immediately intubated, taken to the operating room, and placed on cardiopulmonary bypass by means of groin cannulation. The heart was exposed, and when the left atrium was opened, the pyrolite disc was found in the left atrium. The larger (upstream) strut of the Bjork-Shiley prosthesis was missing and could not be found by thorough examination of the atrium and ventricle (Fig. I). There was no paravalvular leak and only trace aortic regurgitation. The fractured prosthesis was replaced with a 29 mm. Hancock xenograft valve, and the patient was separated from cardiopulmonary bypass with only modest difficulty. The missing strut was noted in the left ventricle on the postoperative chest roentgenograms (Fig. 2). Severe neurologic symptoms persisted postoperatively, thought to be secondary to the long period of preoperative anoxia and shock. The patient's rehabilitation was slow, but he ultimately was discharged from the hospital 6 weeks postoperatively. He has
The Journal of
I 38
McEnany, Wheeler, Austen
progressed minimally over the ensuing 3 years and has had one episode of subacute bacterial endocarditis in 1976, for which he was treated with intravenous antibiotics only. During this episode, the murmur of aortic regurgitation became strikingly louder. When seen 3 years following the last valve replacement, the blood pressure was 170/30 and signs of moderate left ventricular failure were present.
Discussion The Bjork-Shiley prosthesis has been remarkably free of nonthrombotic mechanical complications, especially after the introduction of the pyrolitic carbon occluder. There have been isolated reports of disc fracture? and sticking of the occluder in the closed position.!' Embolization of a Bjork-Shiley Delrin mitral disc has been reported, associated with autoclave disc distortion and possible deformation of a strut. 6 Strut abnormalities also have led to migration of a BjorkShiley aortic disc, 12 but no previous Bjork-Shiley strut fracture has been reported. The fractured strut of the patient in this report remains embedded in the left ventricular myocardium, and it has been impossible to discern whether there was an inherent structural abnormality associated with its fracturing (Fig. 2). Close examination of the residual valve components by Shiley Laboratories revealed no evident mechanical variance in the materials of the prosthesis. * Temporally closely associated with this experience were two other strut fractures in 29 mm. Bjork-Shiley mitral prostheses.t No subsequent incidents have been reported. Consideration has been given to the possible etiologic relationship of any mechanical twisting of the metal valve apparatus inside the sewing ring for perfect postimplantation orifice alignment. This was unnecessary in our patient, as orientation identical to that of the first (removed) Bjork-Shiley prosthesis was guaranteed before the valve was sewn into the anulus. Of interest in this patient is the retrograde embolization of the disc. Most of the other embolized discs have been found in the abdominal aorta. The missing strut was the upstream (atrial) strut, which would have been fractured ultimately by the force of the disc's closing in ventricular systole (Fig. I). Absence of the strut implies simultaneous fracture of both welds joining the strut to the circular metal seat of the valve. Fracture of only one of the welds most likely would have led to bending of the strut and escape of the disc. Once the disc had escaped, there no longer would be any pressure or tension on the strut, which should, therefore, remain attached to the seat by the one remaining weld.
* Personal
communication from Shiley Laboratories, September.
1975. tPersonal communication from Shiley Laboratories. July. 1975.
Thoracic and Cardiovascular Surgery
The explosive nature of the simultaneous weld disruptions probably carried the occluder and the strut into the left atrium. From there the strut migrated to the left ventricle, whereupon it became embedded in the trabeculae carnae and was not detectable through the atriotomy at the ti me of the third mitral valve replacement. There have been no identifiable complications of the ventricular foreign body. Catastrophic acute mitral regurgitation from prosthetic malfunction is a recognized lethal complication of mitral valve replacement. Successful treatment relies upon immediate reoperation and replacement of the errant valve. Survivors have been reported following reoperation up to 16 hours following acute onset of the symptoms of pulmonary edema secondary to disc migration."?: ia. H All authors agree, however, that the patient should be operated upon immediately when the diagnosis of valve dysfunction is made and that the diagnosis must be made clinically, for the time required for cardiac catheterization usually constitutes a lethal delay. The recent insertion of a radiopaque ring into the disc during manufacture has made it easier to ascertain disc presence in correct relationship to the struts and metal seat of the valve. This information will also be helpful in making correct early diagnosis in those patients with acute thrombotic obstruction of the BjorkShiley valve, which, like all disc valves, may have the propensity to occluder entrapment, especially in patients not receiving adequate anticoagulation. I;; Increased experience and familiarity with the normal echocardiographic patterns of the various valve prostheses may help in the triage of a patient in whom the diagnosis is not certain. 16. Ii However, time should not be taken from the rapid transport of such a patient to the operating room for even these simple studies if the constellation of ( I) previous prosthetic val ve replacement, (2) acute onset of pulmonary edema and cardiogenic shock, and (3) absence of prosthetic sounds is present. The patient in this report did not have a chest roentgenogram prior to transfer to the operating room, which was initiated as soon as the surgeon was notified of his presenting symptoms. The preoperative diagnosis was disruption of the sewing ring secondary to recurrent prosthetic endocarditis. The symptoms, however, mandated immediate valve replacement in this comatose patient. The problem of acute prosthetic valve failure is uncommon and, most assuredly, will become even less frequent with the increasing use of biological prostheses, which fail much more gradually. Immediate operation remains the only rational approach to the patient with massive prosthetic dysfunction.
Volume 78
Fracture of mitral prosthetic strut
Number 1
1 39
July, 1979
REFERENCES Book K: Mitral valve replacement with the Bjork-Shiley tilting disc valve. Scand 1 Thorne Cardiovasc Surg 8: Suppl 12:1-28. 1974 2 Henze A. Fortune RL: Regurgitation and haernolysis in artificial heart valves. Scand 1 Thorne Cardiovasc Surg
II
12
8:167-175. 1974 3 Maroiias 1M. Rufilanchas 11. Yillagra F. Juffe A. Miranda AL. Iglesias A. Figuera D: Isolated mitral valve replacement with the Bjork-Shiley prosthesis in 100 consecutive patients. Short and long-term results. 1 Car-
13
diovasc Surg 18:575-581. 1977 -I Bjork YO: The central flow tilting disc valve prosthesis
5
6
7
8
9
(Bjork-Shiley) for mitral valve replacement. Scand 1 Thorac Cardiovasc Surg 4:15-23. 1970 Jones AA. Otis lB. Fletcher GF. Roberts WC: A hitherto undescribed cause of prosthetic mitral valve obstruction. 1 THORAC CAROIOVASC SURG 74:116-117. 1977 Messmer B1. Rothlin M. Senning A: Early disc dislodgment. An unusual complication after insertion of a Bjork-Shiley mitral valve prosthesis. 1 THORAC CARDIOVASC SLRG 65:386-390. 1973 Norenberg DD, Evans EW. Gundersen AE. Abellera RM; Fracture and embolization of a Bjork-Shiley disc. 1 THORAC CARDIOVASC SLRG 74:925-927, 1977 Zumbro GL. Cundy PE lr. Fishback ME, Galloway RF: Strut fracture in De Bakcy valve. 1 THORAC CAROIOVASC SURG 74:469-470, 1977 Nathan Ml: Strut fracture. A late complication of Beall mitral valve replacements. Ann Thorac Surg 16:610-
613, 1975 10 Ansbro 1. Clark R, Gerbode F: Successful surgical cor-
14
15
rection of an ernbolized prosthetic valve poppet. 1 THORAC CARDIOVASC SURG 72: 130-132, 1976 Saunders CR, Rossi NP, Rittenhouse EA: Failure of a Bjork-Shiley mitral valve prosthesis to open. Clinical recognition. 1 Cardiovasc Surg 18:571-574, 1977 Mulder GA: Discussion of Bjork YO, Henze A, Holmgren A: Five years' experience with the BjorkShiley tilting disc valve in isolated aortic valvular disease. 1 THORAC CARDIOVASC SURG 68:393-404, 1974 Roberts AK, Lambert Cl, Mitchel BF: Embolization of disc occluder of a Wada-Cutter mitral prosthesis with survival. Ann Thorac Surg 21:361-364, 1976 Gelfand ET, Callaghan lC, Taylor RF: Survival after late disc dislodgment of a mitral Wada-Cutter prosthesis. Can 1 Surg 21:248, 1978 Moreno-Cabral RJ, McNamara 11, Marniya RT, Brainard Sc. Chung GKT: Acute thrombotic obstruction with Bjork-Shiley valves. 1 THORAC CARDIOVASC SURG 75:
321-330, 1978 16 Douglas lE, Williams GD: Echocardiographic evaluation of the Bjork-Shiley prosthetic valve. Circulation SO: 52-57, 1974 17 Srivastava TN, Hussain M, Gray LA Jr, Flowers NC: Echocardiographic diagnosis of a stuck Bjork-Shiley aortic valve prosthesis. Chest 70:94-98, 1976 18 Boe BB, Fishman NH, Hutchinson lC, Goodenough SH: Occluder disruption of Wada-Cutter valve prosthesis. Ann Thorac Surg 20:256-264, 1975 19 Hughes DA, Leatherman LL, Norman rc, Cooley DA: Late embolization of prosthetic mitral valve occluder with survival following reoperation. Ann Thorac Surg 19:
212-215, 1975