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Aortic root triangulation as a cause of sudden death
Biomcd. & Pharmcofher.. 43 (1989) 381-384 0 Elsevier, Paris
381
ortic root triangulation as a cause of sudden death P.M. SAGAR’, G.W. DYKE’ and L.M. GERLIS2 ’ Department of Surgery, Leeds General Infirmary, Leeds LSI 3EX, UK; and
’ Cardiothoracic institute, Brompton Road, Fulham Road, London, UK (Received 10 Februafy 1989; accepted 24 March 1989)
We have reviewed an autopsy series of thirty-six patients who died suddenly after nceiving a Starr-Edwards aortic valve prosthesis. In fifteen of the thirty-six explanted valves, the aortic outlet was narrowed with the three-legged prosthetic cage causing a triangular distortion of the wall. In the remaining twenty-one patients, the cause of sudden death was not related to failure of the mechanical valve. Although aortic root triangulation would appear to he an uncommon complication with the Starr-Edwards prosthesis, these findings emphasise the need to carefully size the aortic root diameter at the time of surgery, whilst the known problems of morbidity and mortality with mechanical heart valves should continue to stimulate those developing conservative valve reconstruction.
Summary -
aortic valve / sudden death / coaservative valve reconstmction
R&urn6 -
La deformation triangulaire de la racine aortigue, cause de mart subite. Les auteurs ont passe en revue les autopsiesde trente-sixmaladesd&d& subitementalorsqu’ilsportaientune prothese de valve aortique de type Starr-Edwards. Sur quinze des trente-six valves retirees, l’ortjice d’evacuation aortique Ptait rtQrt+ipar la cage en trepied de la protht%e responsable dune deyormation en triangle de la paroi. Chez les vingt-et-un autres sujets, la cause de la mort subite n Wait pas lide d une deTaillance de la valve mecanique. h&me si la deyormation en triangle de la racine aortique apparait comme une complication inhabituelle de la prothese de Starr-Edwards, ces resultats soulignent la necessitt! de calibrer soigneusement le diametre de la racine aortique ri un moment oti les problemes connus de morbidite et de mortalire associes aux valves cardiaques mecaniques devraient continuer d stimuler ceux qui developpent la reconstruction conservatrice de la valve. wtve aortiqneI mart subite / reeenstmctioncenservatrieede la v&e
Introduction Many types of mechanical and bioprosthetic valves have been devised and implanted since the first implantation of an artificial valve by Hufnagel in 1953 [l]. Perhaps one of the most successful has been the Starr-Edwards aortic valve which incorporates a ball in a cage. More than 139 000 of the currently used silastic ball variety have been implanted world-wide [3]. As with other types of mechanical heart valve prosthesis, many
complications have been reported ranging from infection and perivalvular leak to thromboembolism, valve thrombosis and valve migration. A complication peculiar to this style of valve is ball immobilisation consequent upon distortion of the aortic root. Such a complication has, however, been reported only rarely [2]. We have reviewed a series of 36 patients who had received StarrEdwards aortic valves and died suddenly, in 15 of whom autopsy examination revealed ball immobilisation.
382
P.M. Sagar et al.
ntae autonsy records and explanted prosthetic valves of 36 patients who had died suddenly after insertion of Starr-Edwards aortic valve prostheses were obtained. All of the autopsies were performed by one of the authors (LMG). The valves had been implanted over a period of years from 1966 by experienced surgeons working at Killingbeck Hospital, Leeds, UK. The explanted valves were examined, in particular, for any distortion of the aortic root. This took the form of a triangular deformity with the aortic wall being stretched in a transverse piane by the cage frame to such an extent that it interfered with the proper movement of the ball (Fig. 1). The degree of this “triangulation” was subjectively assessed by one patito!@st (LMG) as mild moderate or severe.
Case history I
failure. An emergency aortic valve replacement was performed using a Starr-Edwards aortic caged ball prosthesis (Model No. 2320), at which time the aortic root was found to be almost totally destroyed by active vegetations. Although successfully weaned off cardiopulmonary bypass, the patient deteriorated in the early postoperative period with progressive acidosis, poor renal output and impaired cerebral function. He died on the fifth postoperative day. At post mortem the heart weighed 675 g. All of the chambers were dilated and there was marked left ventricular hypertrophy. The aortic wall showed marked triangulation around the base of the prosthesis and, although the prosthesis was in a good position and the suture line intact, there was considerable restriction of ball movement (Fig. la). There was well-marked subendocardial haemorrhage with involvement of the left bundle branch fibres and areas of subendocardial myo
A 36-year old male presented with infective endocar&is. Cardiac oatheterisation revealed gross aottic
Case history 2
insufficiency with a pulmonary wedge pressure a!most equal to the recorded aortic diastolic pressure. Left ventricular function was considerably impaired. He subsequently developed terminal low output cardiac
A 45-year old man presented with a 2-year history of effort dyspnoea. His past medical history in&dad rheumatic chorea as a child. Angiography demonstrated a calcified incompetent aortic valve and significant
Fig. 1. Autopsy specimens in which the Starr-Edwards caged ball prosthesis was used to replace the aortic valve. The ascending aorta has been transected and the valve observed from the outflow aspect. Both cases demonstrate marked triangulation with restriction of ball movement. a), Case 1; b). Case 2.
Am-ticroot triangulation as a cause of sudden death mitral incompetence. Cardiac catheterisation showed moderate pulmonary hypertension with a mean wedge pressure of Id mmHg rising to 28 mmHg on exercise. An aortic valve replacement was performed using a Starr-Edwards aortic caged ball prosthesis along with a mitral valve annuloplasty. Severe left ventricular hypertrophy was noted. His postoperative recovery was uneventful and he remained well for IS months but then died suddenly. At post mortemthe heart weighed 745 g and showed gross dilatation and hypertrophy of the ieft ventricle.
383
Discussion An aortic ou~ow obst~~ion
effect has long been recagnised with the Starr-Edwards prosthesis and a small decrease in the aortic root area would accentuate this effect. Although the phenomenon of triangulation was described in I968 IZL it has not been edely reported even in large series reviewing the performance of this valve. Interestingly, all of these 15 patients received a version of the prosthesis in which the cage struts were cloth covered, the manufacture of which was discontinued in 1976 - subsequent models leaving the cage struts bare. Nevertheless, the potential for ball i~obilisation secondary to aortic root triangulation with 3 strutted frames remains. The appearance of the aortic root at post mortem would be at variance with conditions during life, since the lack of internal pressure removes the variation in the diameter of the aorta which is seen in life with changing systolicl’ diastolic pressure and consequent elastic recoil of the wall. In addition, the triangular deformity could be accentuated by shrinkage caused by the formalin fixation process. The fact that 10 out of 15 patients died in the postoperative period (i.e., within 28 days) may suggest that inaccurate sizing of the aortic root and insertion of a prosthesis with an inappropriately large base diameter was at least partly responsible. The elastic aortic wall would conform to an angulated contour in which the distance from the centre of the cage to the
There was fibrin clot on the struts of the prosthesis and on the inflow aspect of the ball and, in particular, there was marked triangulation of the aortic wall around the valve struts with impairment of ball movement {Fig, lb)_
Rwults Varying degrees of triangufation of the aortic root were found in 15 out of the 36 explanted valves examined (Table 1) No evidence of aortic root triangulation was found in the other 21 cases where the cause of sudden unexpected death was attributable to other reasons. Ten of those in whom triangulation was demonstrated (67 %) died within 28 days of their operation. There was no correlation between the original valve pathology, age or sex and the subsequent development of triangulation. All of the patients had undergone aortic valve replacement using the Starr-Edwards model no. 2320 in which the 3 cage struts are cloth-covered. This model was discontinued in 1976.
Table I. Starr-Edwards aortic valves removed at autopsy which demonstrated triangulation. Age at ~~~~~~~~~~~ 36 35 56 48 50 36 5f 36 55 53 48 45 64 I9 41
S&X M M
Sumiviil
IE
< 28 days
+++
Congenital
c 20 days < 28 days
++ +++
6 years < 28 days < 28 days 4 months < 28 days < 28 days 15 months c 28 days 18 months < 28 days 8 months K 28 days
f-+ ++ +-I-+ ++ ++ ++ -++-t”+ +++ + ++ 4+
F
RhF
: M
K IE RhF
G M F : G F
&pee of s~~n~~~~ti~~
&wise
EF RhF Congenital RhF RhF Congenital IE
IE, Infective endocarditis; RhF, IKheumaticfever; Congenital, Congenital aortic steno&. Degree of triangulation : +, mild: -I-f , moderate; -I-+ + , severe.
384
P.M. Sugar et al.
midpoint of the flattened sides is less than the radius of the ball. The movement of the ball would thus be impeded. Such an effect would be more marked with the triangular defomration produced by 3-legged cages than with the qua&angular defo&%y produced by a 4-legged frame. Restriction of ball movement would be further increased if the long axis of the pros!.hesis was at an angle with the long axis of the aorta. In conclusion, a review of an autopsy series of 36 patients with Starr-Edwards aortic valve prostheses who had died suddenly revealed the presence of a degree of triangulation in 15. This
phenomenon may be an under-reported death in this group of patients.
cause of
rences Hufnagel C.A. & Harvey W.P. (1953) The surgical ’ correction of aortic regurgitation : preliminary report. Bull. Georgetown U. Med. Ctr. 6, 60 2 Quattlebaum EW., Kalke B., Edwards J.E. & Lillehei C.W. (1968) Obstruction of the aorta by prosthetic aortic valve. J. Iploruc. Curdiovasc. Surg. 55, 231 Clinical Report (1984) American 3 Starr-Edwards Edwards Laboratories
381
ortic root triangulation as a cause of sudden death P.M. SAGAR’, G.W. DYKE’ and L.M. GERLIS2 ’ Department of Surgery, Leeds General Infirmary, Leeds LSI 3EX, UK; and
’ Cardiothoracic institute, Brompton Road, Fulham Road, London, UK (Received 10 Februafy 1989; accepted 24 March 1989)
We have reviewed an autopsy series of thirty-six patients who died suddenly after nceiving a Starr-Edwards aortic valve prosthesis. In fifteen of the thirty-six explanted valves, the aortic outlet was narrowed with the three-legged prosthetic cage causing a triangular distortion of the wall. In the remaining twenty-one patients, the cause of sudden death was not related to failure of the mechanical valve. Although aortic root triangulation would appear to he an uncommon complication with the Starr-Edwards prosthesis, these findings emphasise the need to carefully size the aortic root diameter at the time of surgery, whilst the known problems of morbidity and mortality with mechanical heart valves should continue to stimulate those developing conservative valve reconstruction.
Summary -
aortic valve / sudden death / coaservative valve reconstmction
R&urn6 -
La deformation triangulaire de la racine aortigue, cause de mart subite. Les auteurs ont passe en revue les autopsiesde trente-sixmaladesd&d& subitementalorsqu’ilsportaientune prothese de valve aortique de type Starr-Edwards. Sur quinze des trente-six valves retirees, l’ortjice d’evacuation aortique Ptait rtQrt+ipar la cage en trepied de la protht%e responsable dune deyormation en triangle de la paroi. Chez les vingt-et-un autres sujets, la cause de la mort subite n Wait pas lide d une deTaillance de la valve mecanique. h&me si la deyormation en triangle de la racine aortique apparait comme une complication inhabituelle de la prothese de Starr-Edwards, ces resultats soulignent la necessitt! de calibrer soigneusement le diametre de la racine aortique ri un moment oti les problemes connus de morbidite et de mortalire associes aux valves cardiaques mecaniques devraient continuer d stimuler ceux qui developpent la reconstruction conservatrice de la valve. wtve aortiqneI mart subite / reeenstmctioncenservatrieede la v&e
Introduction Many types of mechanical and bioprosthetic valves have been devised and implanted since the first implantation of an artificial valve by Hufnagel in 1953 [l]. Perhaps one of the most successful has been the Starr-Edwards aortic valve which incorporates a ball in a cage. More than 139 000 of the currently used silastic ball variety have been implanted world-wide [3]. As with other types of mechanical heart valve prosthesis, many
complications have been reported ranging from infection and perivalvular leak to thromboembolism, valve thrombosis and valve migration. A complication peculiar to this style of valve is ball immobilisation consequent upon distortion of the aortic root. Such a complication has, however, been reported only rarely [2]. We have reviewed a series of 36 patients who had received StarrEdwards aortic valves and died suddenly, in 15 of whom autopsy examination revealed ball immobilisation.
382
P.M. Sagar et al.
ntae autonsy records and explanted prosthetic valves of 36 patients who had died suddenly after insertion of Starr-Edwards aortic valve prostheses were obtained. All of the autopsies were performed by one of the authors (LMG). The valves had been implanted over a period of years from 1966 by experienced surgeons working at Killingbeck Hospital, Leeds, UK. The explanted valves were examined, in particular, for any distortion of the aortic root. This took the form of a triangular deformity with the aortic wall being stretched in a transverse piane by the cage frame to such an extent that it interfered with the proper movement of the ball (Fig. 1). The degree of this “triangulation” was subjectively assessed by one patito!@st (LMG) as mild moderate or severe.
Case history I
failure. An emergency aortic valve replacement was performed using a Starr-Edwards aortic caged ball prosthesis (Model No. 2320), at which time the aortic root was found to be almost totally destroyed by active vegetations. Although successfully weaned off cardiopulmonary bypass, the patient deteriorated in the early postoperative period with progressive acidosis, poor renal output and impaired cerebral function. He died on the fifth postoperative day. At post mortem the heart weighed 675 g. All of the chambers were dilated and there was marked left ventricular hypertrophy. The aortic wall showed marked triangulation around the base of the prosthesis and, although the prosthesis was in a good position and the suture line intact, there was considerable restriction of ball movement (Fig. la). There was well-marked subendocardial haemorrhage with involvement of the left bundle branch fibres and areas of subendocardial myo
A 36-year old male presented with infective endocar&is. Cardiac oatheterisation revealed gross aottic
Case history 2
insufficiency with a pulmonary wedge pressure a!most equal to the recorded aortic diastolic pressure. Left ventricular function was considerably impaired. He subsequently developed terminal low output cardiac
A 45-year old man presented with a 2-year history of effort dyspnoea. His past medical history in&dad rheumatic chorea as a child. Angiography demonstrated a calcified incompetent aortic valve and significant
Fig. 1. Autopsy specimens in which the Starr-Edwards caged ball prosthesis was used to replace the aortic valve. The ascending aorta has been transected and the valve observed from the outflow aspect. Both cases demonstrate marked triangulation with restriction of ball movement. a), Case 1; b). Case 2.
Am-ticroot triangulation as a cause of sudden death mitral incompetence. Cardiac catheterisation showed moderate pulmonary hypertension with a mean wedge pressure of Id mmHg rising to 28 mmHg on exercise. An aortic valve replacement was performed using a Starr-Edwards aortic caged ball prosthesis along with a mitral valve annuloplasty. Severe left ventricular hypertrophy was noted. His postoperative recovery was uneventful and he remained well for IS months but then died suddenly. At post mortemthe heart weighed 745 g and showed gross dilatation and hypertrophy of the ieft ventricle.
383
Discussion An aortic ou~ow obst~~ion
effect has long been recagnised with the Starr-Edwards prosthesis and a small decrease in the aortic root area would accentuate this effect. Although the phenomenon of triangulation was described in I968 IZL it has not been edely reported even in large series reviewing the performance of this valve. Interestingly, all of these 15 patients received a version of the prosthesis in which the cage struts were cloth covered, the manufacture of which was discontinued in 1976 - subsequent models leaving the cage struts bare. Nevertheless, the potential for ball i~obilisation secondary to aortic root triangulation with 3 strutted frames remains. The appearance of the aortic root at post mortem would be at variance with conditions during life, since the lack of internal pressure removes the variation in the diameter of the aorta which is seen in life with changing systolicl’ diastolic pressure and consequent elastic recoil of the wall. In addition, the triangular deformity could be accentuated by shrinkage caused by the formalin fixation process. The fact that 10 out of 15 patients died in the postoperative period (i.e., within 28 days) may suggest that inaccurate sizing of the aortic root and insertion of a prosthesis with an inappropriately large base diameter was at least partly responsible. The elastic aortic wall would conform to an angulated contour in which the distance from the centre of the cage to the
There was fibrin clot on the struts of the prosthesis and on the inflow aspect of the ball and, in particular, there was marked triangulation of the aortic wall around the valve struts with impairment of ball movement {Fig, lb)_
Rwults Varying degrees of triangufation of the aortic root were found in 15 out of the 36 explanted valves examined (Table 1) No evidence of aortic root triangulation was found in the other 21 cases where the cause of sudden unexpected death was attributable to other reasons. Ten of those in whom triangulation was demonstrated (67 %) died within 28 days of their operation. There was no correlation between the original valve pathology, age or sex and the subsequent development of triangulation. All of the patients had undergone aortic valve replacement using the Starr-Edwards model no. 2320 in which the 3 cage struts are cloth-covered. This model was discontinued in 1976.
Table I. Starr-Edwards aortic valves removed at autopsy which demonstrated triangulation. Age at ~~~~~~~~~~~ 36 35 56 48 50 36 5f 36 55 53 48 45 64 I9 41
S&X M M
Sumiviil
IE
< 28 days
+++
Congenital
c 20 days < 28 days
++ +++
6 years < 28 days < 28 days 4 months < 28 days < 28 days 15 months c 28 days 18 months < 28 days 8 months K 28 days
f-+ ++ +-I-+ ++ ++ ++ -++-t”+ +++ + ++ 4+
F
RhF
: M
K IE RhF
G M F : G F
&pee of s~~n~~~~ti~~
&wise
EF RhF Congenital RhF RhF Congenital IE
IE, Infective endocarditis; RhF, IKheumaticfever; Congenital, Congenital aortic steno&. Degree of triangulation : +, mild: -I-f , moderate; -I-+ + , severe.
384
P.M. Sugar et al.
midpoint of the flattened sides is less than the radius of the ball. The movement of the ball would thus be impeded. Such an effect would be more marked with the triangular defomration produced by 3-legged cages than with the qua&angular defo&%y produced by a 4-legged frame. Restriction of ball movement would be further increased if the long axis of the pros!.hesis was at an angle with the long axis of the aorta. In conclusion, a review of an autopsy series of 36 patients with Starr-Edwards aortic valve prostheses who had died suddenly revealed the presence of a degree of triangulation in 15. This
phenomenon may be an under-reported death in this group of patients.
cause of
rences Hufnagel C.A. & Harvey W.P. (1953) The surgical ’ correction of aortic regurgitation : preliminary report. Bull. Georgetown U. Med. Ctr. 6, 60 2 Quattlebaum EW., Kalke B., Edwards J.E. & Lillehei C.W. (1968) Obstruction of the aorta by prosthetic aortic valve. J. Iploruc. Curdiovasc. Surg. 55, 231 Clinical Report (1984) American 3 Starr-Edwards Edwards Laboratories