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Isolated mitral valve replacement with the Kay-Shiley prosthesis
J THORAC CARDIOVASC SURG 80:45-49, 1980
Isolated mitral valve replacement with the Kay-Shiley prosthesis Long-term follow-up and recommendations Eighty patients underwent isolated mitral valve replacement with the Kay-Shiley prosthesis during a 6 year period (September, 1966, to October, 1972) at Walter Reed Army Medical Center. One-hundred percent follow-up has been achieved with this group. Sixty-four percent of this group have experienced one or more thromboembolic episodes (TEEs), for a TEE rate of 28.7 episodes per 1,000 patient months at risk. The 5 year survival rate is 45%. Eleven of43 (25%) late deaths resulted from TEEs, and 13 of43 (30%) late deaths were secondary to the hemorrhagic complications of long-term anticoagulant therapy. The dismal TEE rate prompted us to initiate a policy of elective replacement of all Kay-Shiley mitral prostheses. Eighteen of the 26 survivors underwent replacement of the Kay-Shiley mitral prosthesis. The other eight patients either declined reoperation or were not considered suitable candidates. The reoperative mortality rate was 22% (41J8). Fifteen of 18 explanted prostheses revealed a yellow discolored. grooved occluder disc with loosely adherent clot. We recommend elective replacement of Kav-Shiley mitral prostheses in all patients in whom the risk of operation is reasonable.
Thomas E. Bowen, Colonel, MC, USA, Rostik Zajtchuk, Colonel, MC, USA, Walter H. Brott, Colonel, MC, USA, and Carlos M. deCastro, Colonel, MC, USA (Ret.), Washington, D. C., and Bethesda, Md.
T
he Kay-Shiley mitral disc prosthesis (Model K or Type I) was first used clinically in 1965. 1, 2 The unacceptably high thrombogenicity of that model led to its modification (Model T or Type II), which consisted primarily of decreasing the amount of exposed metal at the orifice (Fig. 1). During a 6 year period (September, 1966, to October, 1972), 80 patients at Walter Reed Army Medical Center underwent isolated mitral valve replacement with the Type II Kay-Shiley mitral prosthesis. Use of the Kay-Shiley mitral prosthesis was discontinued in 1972 because of the suspicion of an unacceptably high thromboembolism rate. This report presents the findings of 100% follow-up of those 80 patients who underwent isolated mitral replacement From the Thoracic Surgery Service, Walter Reed Army Medical Center, Washington, D. C. 20012, and the Department of Surgery, Uniformed Services University of Health Sciences, Bethesda, Md. 20014. Received for publication Oct. 24, 1979. Accepted for publication Nov. 20, 1979. Address for reprints: Thomas E. Bowen, M.D., Box 105, Thoracic and Cardiovascular Surgical Service, Letterman Army Medical Center, Presidio of San Francisco, Calif. 94129.
with the Kay-Shiley prosthesis. The duration of follow-up currently ranges from 7 to 13 years. Patients There were 47 females and 33 males in this patient group, ranging in age from 7 to 63 years, the median age being 43 years. Sixty-eight patients were in New York Heart Association (NYHA) Functional Class III and 12 were in Class IV. There were no patients in Class I or II. The predominant lesion was stenosis in 25, insufficiency in 32, and a mixed lesion in 23. The diverse causes for operation were rheumatic disease in 59, arteriosclerotic heart disease in seven, subacute bacterial endocarditis in six, prosthesis malfunction in three, atrioventricular canal in two, and myxoma, trauma, and endocardial fibroelastosis in one each. Twenty-five of the 80 had normal sinus rhythm; the other 55 had atrial fibrillation. Thirty of the 80 patients had undergone one or more antecedent mitral operations. Multiple surgical approaches had been employed for replacement. All prostheses had been placed in a supra-annular position with the use of interrupted suture technique and normothermic perfusion. Postop45
The Journal of Thoracic and Cardiovascular Surgery
46 Bowen et al.
Fig. 1. The Type II Kay-Shiley mitral prosthesis initially employed in this series.
Table I. Cause of late death following isolated Kay-Shiley mitral valve replacement Calise of death TEE or prosthetic thrombosis Hemorrhage Nonthrombotic (valve related ) Miscellaneous Cardiac related Not cardiac related Cause indeterminate
'--N-O-.--
%
11 13
25 30
6
15
9
20
2 2
5 5
Legend: TEE, Thromboembolic episode.
eratively, all patients received long-term sodium warfarin (Coumadin) therapy, initiated on the third or fourth postoperative day. All patients were subsequently permanently maintained on appropriate daily dosages of sodium warfarin to maintain the prothrombin time at or as close as possible to two times the control value. Findings There were 10 early deaths (within 30 days) for an overall operative mortalit y rate of 12.5%-9% (6/68) for patients in preoperative NYHA Class III and 33% (4/ 12) for those in Class IV. The 10 operative deaths were secondary to low cardiac output (three), hemorrhage (two), central nervous system damage (two), myocardial infarction (one) , and retrograde aortic dissection (one). Follow-up of the 70 operative survivors revealed 43 late deaths and 27 current survivors. Long-term followup of the NYHA Class IV subgroup was very disheartening , as only two of the original 12 (17%) were alive I year postoperatively. By comparison , 74% (50/68) of
the NYHA Class III subgroup had survived for I year . To date 64% (45170) of the operative survivors have experienced one or more thromboembolic episodes (TEEs) . This experience represents a TEE rate of 28.7 episodes per 1,000 patient-months at risk . This figure is corroborated by Wellons and associates," who reported a TEE rate of 24.7 episodes per 1,000 patient months at risk in patients with the Kay-Shiley mitral prosthesis. These data have been actuarially analyzed" and are depicted in Fig. 2 . The causes of late death in this series (43/70) are listed in Table I. Eleven of the 43 (25%) deaths were the direct result of TEEs or prosthesis thrombosis or both . Six of the II (55 %) patients who died underwent autopsy. The cause of death in the other five was believed by the clinician to be clearly thrombotic in origin. Three of the five not subjected to autopsy had prothrombin times in the therapeutic range when they presented with sudden grave focal findings . The other two patients not subjected to autopsy did not have prothrombin times in the therapeutic range . One died suddenly 4 days after discontinuing anticoagulant therapy preparatory to a dental procedure . The other had a partial thromboplastin time of 14 seconds the day before and presented with hemiplegia; obtundation and death rapidly followed. Even more appalling is the realization that 13 of the 43 (30%) late deaths were due not to the disease but to the therapy (sodium warfarin) itself, Eleven of the 13 (85%) patients who died secondary 10 the hemorrhagic complication of anticoagulant therapy underwent necropsy. In the twelfth patient the cause of death was confirmed neurosurgically during drainage of subdural hematomas. Six other deaths (15%) were valve related but nonthrombotic , being secondary to congestive heart failure. In four of these cases there were large periprosthetic leaks and in the other two, fluoroscopy demonstrated sticking of the prosthetic disc occluder secondary to grooving of the silicone rubber disc by the Stellite struts . In 73% of the deaths believed to be prosthesis related, the cause of death was confirmed by autopsy or neurosurgical operation (one case) . Two patients who died of causes not related to the prosthesis were found at autopsy to have thrombus on the Kay-Shiley prosthesis. One had never experienced a TEE , and the other had had four TEEs. The overall survival rate is actuarially depicted in Fig. 3. Only 20% of the long-term survivors were alive and TEE free at 5 years. Conclusions Documentation of the high TEE rate in this patient group retrospectively justified our decision to discon-
Volume 80
MVR with Kay-Shiley prosthesis
Number 1
47
July, 1980
100
100
f:
80
60
" ' - - - WELLONS 83 CASES
w
w cr u,
w w
CONFIDENCE !I, LI9 0% MITS
80
9 0 % CONFIDENCE LI MITS
_ W RAMC 80 CASES
40
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WRAMC 80 CASES
--
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.L
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0
I MO
2
3 4 5 6 7 8 YEARS R)ST OPERATION
9
10
II
12
Fig. 2. Actuarial analysis of thromboembolism according to the method of Anderson and colleagues." The first thromboembolic event removes the patient from the curve. The series of Wellons and associates" is also depicted. TEE. Thromboembolic episodes. tinue use of the Kay-Shiley prosthesis in late 1972. Of lesser but still significant concern is the problem of Kay-Shiley disc occluder wear. The unacceptable TEE rate and disc occluder wear, coupled with the realization that the incidence of thromboembolism does not level off but in fact relentlessly persists, led us to recommend that all patients in whom the risk of operation was reasonable undergo elective replacement of the Kay-Shiley mitral prosthesis . This group comprised 27 surviving patients. One survivor was removed for cause from the series following aortic valve replacement. Three others refused reoperation. Two of these three were in atrial fibrillation, and all three were free of TEEs . Four others were not offered reoperation: Two, both in atrial fibrillation and both having had TEEs, were bypassed because of old age with associated ASHD; one because of poor pulmonary function (atrial fibrillat ion with no antecedent TEE) , and one because of grave neurologic status secondary to a TEE . One other patient (atrial fibrillation) developed grave neurologic status secondary to TEEs while awaiting scheduled reoperation and was subsequently not offered reoperation . The remaining 18 patients underwent reoperation . These 18 pat ient s had experienced a total of 58 TEEs . Twelve were in atrial fibrillation . Two of the 18 had been TEE free. Some degree of peri prosthetic leak was noted in five of them (28%) . At reoperation three of 18 Kay-Sh iley mitral prostheses were free of clot and the disc wa s only minimally grooved or discolored. The
I
MO
2
3
4
5
6
7
8
9
10
II
12
YEARS POST OPERATION
Fig. 3. Actuarial analysis of survival according to the method of Anderson and colleagues." The series of Wellons and associates" is also depicted.
Fig. 4. Explanted Kay-Shiley mitral prosthesis illustrating thrombuson ventricular aspect of the occluder disc. other 15 had grooved disc s , yellow discoloration of the occluder disc , and clot on the disc . Three of these 15 also had clot on the sewing ring or the struts . Disc thrombus was primarily white and usually located on the ve ntricular aspect of the disc (Fig . 4). Sixteen of the 18 patients underwent mitral valve replacement alone. One other patient underwent replacement of the mitral prosthe sis and the native tricuspid valve . The final patient unde rwent replacement of the nati ve aortic valve , but the mitral prosthesis was not rem o ved because a prom inent segment of the Kay-Sh iley sewing ring and a large block of calcium were palpable posteriorly in the
48
Bowen et al.
The Journal of Thoracic and Cardiovascular Surgery
Fig. SA. Method of fabrication of the universal valve holder from a uterine tenaculum.
Fig. SC. The universal valve holder being employed to manipulate the prosthesis during excision.
Fig. SB. Universal valve holder in vitro. atrioventricular groove . It was the surgeons' opinion that excison of the Kay-Shiley prosthesis would leave inadequate tissue posteriorly to allow rereplacement and would very likely result in subsequent atrioventricular disruption . This man had experienced one TEE , and examination of the prosthesis through the aortic
root revealed it to be free of thrombus with no significant evidence of wear. All reoperations were performed through a median sternotomy with systemic and topical hypothermia. No misadventures occurred during sternal splitting . A universal valve holder fashioned from a uterine tenaculum* (Fig . 5) facilitated exposure and manipulation of the prosthesis during excison . The Kay -Shiley prostheses were replaced with either Bjork-Shiley or porcine *Originally designed in 1966 at Walter Reed Army Medical Center by M. E. Fishback, M.D ., Augusta, Ga.
Volume 80 Number 1
MVR with Kay-Shiley prosthesis
49
July, 1980
prostheses attached with horizontal, Teflon-bolstered mattress sutures. There were four operative deaths (22%), but there have been no late deaths. One operative death resulted from myocardial infarction secondary to suture encirclement of the circumflex coronary artery. Two deaths were secondary to hemorrhage, one following posterior atrioventricular disruption and the other following irreparable superior caval laceration during decannulation. The fourth death occurred after tricuspid replacement and mitral rereplacement. This patient had tissue interference within the disc of the Bjork-Shiley valve. Death subsequently resulted from a combination of hemorrhage and low output state. Recommendations The Kay-Shiley mitral prosthesis, which enjoyed relatively wide clinical usage in the late I960s and early 1970s, is subject to moderate-to-severe occluder disc wear that can cause hang-ups of the disc occluder on the Stellite struts and can produce catastrophic failure. The TEE rate of 28.7 embolic episodes per 1,000 patient-months at risk is unacceptably high. The incidence of TEEs does not level off after a "wear in" period with this prosthesis, but continues in a straight line over the entire period of implantation. Because of the foregoing, we recommend replacement of KayShiley mitral prostheses in all patients in whom reoperation can be performed at a reasonable risk. Reoperation in 18 of 26 long-term survivors in this series revealed that only three valves were essentially normal with regard to disc wear, disc discoloration, and presence of thrombus. The other 15 prostheses had at least moderate disc wear plus gross yellow discoloration of the disc and loosely adherent thrombus on the disc and/or sewing ring and struts. The reoperative mortality rate was 22%. REFERENCES Kay JH, Kawashima Y, Kagawa Y, Tsugi HK, Redington JV: Experimental mitral valve replacement with a new disc valve. Ann Thorac Surg 2:485-498, 1966 2 Lefrak EA, Starr A: Cardiac valve prostheses, New York, 1979, Appleton-Century-Crofts, pp 167-180 3 Wellons HA, Strauch RS, Nolan SP, Muller WH: Isolated mitral valve replacement with the Kay-Shiley disc valve. Actuarial analysis of the long-term results. J THORAC CARDIOVASC SURG 70:862-868, 1975 4 Anderson RP, Bonchek LI, Grunkemeier GL, Lambert LE, Starr A: The analysis and presentation of surgical results by actuarial methods. J Surg Res 16:224-230, 1974
Reviewer's comment I am pleased that the JOURNAL is publishing this article by Bowen, Zajtchuk, Brott, and deCastro, since it points out a number of factors that are extremely important in mitral valve operations. I noted that 32 of their 80 patients had mitral insufficiency. Our belief for many years has been that the majority of patients with pure mitral insufficiency should have mitral valve repair rather than replacement. There are several advantages to mitral valve repair for mitral insufficiency. The incidence of reoperation is less with repair than with replacement, no matter what prosthesis is used. There are fewer peripheral emboli and there is no need for long-term anticoagulant therapy with repair. Thirteen of 40 late deaths in their series were due to hemorrhagic complications following sodium warfarin therapy. With mitral valve repair for mitral insufficiency, anticoagulant therapy can be discontinued in 3 months and should not be used after that. In the article by Bowen, Zajtchuk, Brott, and deCastro, the disc valve was inserted in a supra-annular position. Five of the 18 patients had a periprosthetic leak, for an incidence of 28%. We have found that periprosthetic leak can be virtually eliminated by sewing the prosthetic valve in the subannular position. Our first article on the Kay-Shiley disc valve was published in 1966. However, in an article in Archives of Surgery (98:626-628, 1969) we stressed the importance of using the muscle guard for the prosthesis whenever a disc valve is used in the mitral area. This report was followed in 1974 by an article in THE JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY (68: 30-36, 1974) on a comparative experimental study with the Starr-Edwards ball valve, the Beall disc valve, and the Kay-Shiley disc valve with a muscle guard. This article pointed out the importance of using a muscle guard whenever a prosthetic valve is used in the tricuspid area. The muscle guard is extremely important in that it prevents the muscle from encroaching on a poppet, whether it be a ball or disc. Without a muscle guard, a disc may be captured by the surrounding muscle and, as a consequence, will act as if it were hinged. Grooves then occur on the poppet where the disc moves against the struts. If captured by the muscle, the disc cannot move up and down therefore, clotting and increased thromboembolization occur. In a forthcoming publication of The Annals of Thoracic Surgery, our 13 years of experience with the Kay-Shiley disc valve with a muscle guard for tricuspid replacement in Ebstein's anomaly will be presented. There has been one death in the early postoperative period, resulting from arrhythmia. The other 12 patients are long-term survivors with no complications. I believe there is still not a perfect valve for the mitral area, and I would like to stress the extreme importance of repairing the mitral valve whenever possible. Jermoe Harold Kay, MD. Los Angeles, Calif.
Isolated mitral valve replacement with the Kay-Shiley prosthesis Long-term follow-up and recommendations Eighty patients underwent isolated mitral valve replacement with the Kay-Shiley prosthesis during a 6 year period (September, 1966, to October, 1972) at Walter Reed Army Medical Center. One-hundred percent follow-up has been achieved with this group. Sixty-four percent of this group have experienced one or more thromboembolic episodes (TEEs), for a TEE rate of 28.7 episodes per 1,000 patient months at risk. The 5 year survival rate is 45%. Eleven of43 (25%) late deaths resulted from TEEs, and 13 of43 (30%) late deaths were secondary to the hemorrhagic complications of long-term anticoagulant therapy. The dismal TEE rate prompted us to initiate a policy of elective replacement of all Kay-Shiley mitral prostheses. Eighteen of the 26 survivors underwent replacement of the Kay-Shiley mitral prosthesis. The other eight patients either declined reoperation or were not considered suitable candidates. The reoperative mortality rate was 22% (41J8). Fifteen of 18 explanted prostheses revealed a yellow discolored. grooved occluder disc with loosely adherent clot. We recommend elective replacement of Kav-Shiley mitral prostheses in all patients in whom the risk of operation is reasonable.
Thomas E. Bowen, Colonel, MC, USA, Rostik Zajtchuk, Colonel, MC, USA, Walter H. Brott, Colonel, MC, USA, and Carlos M. deCastro, Colonel, MC, USA (Ret.), Washington, D. C., and Bethesda, Md.
T
he Kay-Shiley mitral disc prosthesis (Model K or Type I) was first used clinically in 1965. 1, 2 The unacceptably high thrombogenicity of that model led to its modification (Model T or Type II), which consisted primarily of decreasing the amount of exposed metal at the orifice (Fig. 1). During a 6 year period (September, 1966, to October, 1972), 80 patients at Walter Reed Army Medical Center underwent isolated mitral valve replacement with the Type II Kay-Shiley mitral prosthesis. Use of the Kay-Shiley mitral prosthesis was discontinued in 1972 because of the suspicion of an unacceptably high thromboembolism rate. This report presents the findings of 100% follow-up of those 80 patients who underwent isolated mitral replacement From the Thoracic Surgery Service, Walter Reed Army Medical Center, Washington, D. C. 20012, and the Department of Surgery, Uniformed Services University of Health Sciences, Bethesda, Md. 20014. Received for publication Oct. 24, 1979. Accepted for publication Nov. 20, 1979. Address for reprints: Thomas E. Bowen, M.D., Box 105, Thoracic and Cardiovascular Surgical Service, Letterman Army Medical Center, Presidio of San Francisco, Calif. 94129.
with the Kay-Shiley prosthesis. The duration of follow-up currently ranges from 7 to 13 years. Patients There were 47 females and 33 males in this patient group, ranging in age from 7 to 63 years, the median age being 43 years. Sixty-eight patients were in New York Heart Association (NYHA) Functional Class III and 12 were in Class IV. There were no patients in Class I or II. The predominant lesion was stenosis in 25, insufficiency in 32, and a mixed lesion in 23. The diverse causes for operation were rheumatic disease in 59, arteriosclerotic heart disease in seven, subacute bacterial endocarditis in six, prosthesis malfunction in three, atrioventricular canal in two, and myxoma, trauma, and endocardial fibroelastosis in one each. Twenty-five of the 80 had normal sinus rhythm; the other 55 had atrial fibrillation. Thirty of the 80 patients had undergone one or more antecedent mitral operations. Multiple surgical approaches had been employed for replacement. All prostheses had been placed in a supra-annular position with the use of interrupted suture technique and normothermic perfusion. Postop45
The Journal of Thoracic and Cardiovascular Surgery
46 Bowen et al.
Fig. 1. The Type II Kay-Shiley mitral prosthesis initially employed in this series.
Table I. Cause of late death following isolated Kay-Shiley mitral valve replacement Calise of death TEE or prosthetic thrombosis Hemorrhage Nonthrombotic (valve related ) Miscellaneous Cardiac related Not cardiac related Cause indeterminate
'--N-O-.--
%
11 13
25 30
6
15
9
20
2 2
5 5
Legend: TEE, Thromboembolic episode.
eratively, all patients received long-term sodium warfarin (Coumadin) therapy, initiated on the third or fourth postoperative day. All patients were subsequently permanently maintained on appropriate daily dosages of sodium warfarin to maintain the prothrombin time at or as close as possible to two times the control value. Findings There were 10 early deaths (within 30 days) for an overall operative mortalit y rate of 12.5%-9% (6/68) for patients in preoperative NYHA Class III and 33% (4/ 12) for those in Class IV. The 10 operative deaths were secondary to low cardiac output (three), hemorrhage (two), central nervous system damage (two), myocardial infarction (one) , and retrograde aortic dissection (one). Follow-up of the 70 operative survivors revealed 43 late deaths and 27 current survivors. Long-term followup of the NYHA Class IV subgroup was very disheartening , as only two of the original 12 (17%) were alive I year postoperatively. By comparison , 74% (50/68) of
the NYHA Class III subgroup had survived for I year . To date 64% (45170) of the operative survivors have experienced one or more thromboembolic episodes (TEEs) . This experience represents a TEE rate of 28.7 episodes per 1,000 patient-months at risk . This figure is corroborated by Wellons and associates," who reported a TEE rate of 24.7 episodes per 1,000 patient months at risk in patients with the Kay-Shiley mitral prosthesis. These data have been actuarially analyzed" and are depicted in Fig. 2 . The causes of late death in this series (43/70) are listed in Table I. Eleven of the 43 (25%) deaths were the direct result of TEEs or prosthesis thrombosis or both . Six of the II (55 %) patients who died underwent autopsy. The cause of death in the other five was believed by the clinician to be clearly thrombotic in origin. Three of the five not subjected to autopsy had prothrombin times in the therapeutic range when they presented with sudden grave focal findings . The other two patients not subjected to autopsy did not have prothrombin times in the therapeutic range . One died suddenly 4 days after discontinuing anticoagulant therapy preparatory to a dental procedure . The other had a partial thromboplastin time of 14 seconds the day before and presented with hemiplegia; obtundation and death rapidly followed. Even more appalling is the realization that 13 of the 43 (30%) late deaths were due not to the disease but to the therapy (sodium warfarin) itself, Eleven of the 13 (85%) patients who died secondary 10 the hemorrhagic complication of anticoagulant therapy underwent necropsy. In the twelfth patient the cause of death was confirmed neurosurgically during drainage of subdural hematomas. Six other deaths (15%) were valve related but nonthrombotic , being secondary to congestive heart failure. In four of these cases there were large periprosthetic leaks and in the other two, fluoroscopy demonstrated sticking of the prosthetic disc occluder secondary to grooving of the silicone rubber disc by the Stellite struts . In 73% of the deaths believed to be prosthesis related, the cause of death was confirmed by autopsy or neurosurgical operation (one case) . Two patients who died of causes not related to the prosthesis were found at autopsy to have thrombus on the Kay-Shiley prosthesis. One had never experienced a TEE , and the other had had four TEEs. The overall survival rate is actuarially depicted in Fig. 3. Only 20% of the long-term survivors were alive and TEE free at 5 years. Conclusions Documentation of the high TEE rate in this patient group retrospectively justified our decision to discon-
Volume 80
MVR with Kay-Shiley prosthesis
Number 1
47
July, 1980
100
100
f:
80
60
" ' - - - WELLONS 83 CASES
w
w cr u,
w w
CONFIDENCE !I, LI9 0% MITS
80
9 0 % CONFIDENCE LI MITS
_ W RAMC 80 CASES
40
...J
~
>
cr :;)
,, ,,
(f)
W
> ~
>-
"'- -- WELLONS 83 CASES
60
_
WRAMC 80 CASES
--
40
...J :;)
o-e 20
::iE :;) u
.L
20
~
0
I MO
2
3 4 5 6 7 8 YEARS R)ST OPERATION
9
10
II
12
Fig. 2. Actuarial analysis of thromboembolism according to the method of Anderson and colleagues." The first thromboembolic event removes the patient from the curve. The series of Wellons and associates" is also depicted. TEE. Thromboembolic episodes. tinue use of the Kay-Shiley prosthesis in late 1972. Of lesser but still significant concern is the problem of Kay-Shiley disc occluder wear. The unacceptable TEE rate and disc occluder wear, coupled with the realization that the incidence of thromboembolism does not level off but in fact relentlessly persists, led us to recommend that all patients in whom the risk of operation was reasonable undergo elective replacement of the Kay-Shiley mitral prosthesis . This group comprised 27 surviving patients. One survivor was removed for cause from the series following aortic valve replacement. Three others refused reoperation. Two of these three were in atrial fibrillation, and all three were free of TEEs . Four others were not offered reoperation: Two, both in atrial fibrillation and both having had TEEs, were bypassed because of old age with associated ASHD; one because of poor pulmonary function (atrial fibrillat ion with no antecedent TEE) , and one because of grave neurologic status secondary to a TEE . One other patient (atrial fibrillation) developed grave neurologic status secondary to TEEs while awaiting scheduled reoperation and was subsequently not offered reoperation . The remaining 18 patients underwent reoperation . These 18 pat ient s had experienced a total of 58 TEEs . Twelve were in atrial fibrillation . Two of the 18 had been TEE free. Some degree of peri prosthetic leak was noted in five of them (28%) . At reoperation three of 18 Kay-Sh iley mitral prostheses were free of clot and the disc wa s only minimally grooved or discolored. The
I
MO
2
3
4
5
6
7
8
9
10
II
12
YEARS POST OPERATION
Fig. 3. Actuarial analysis of survival according to the method of Anderson and colleagues." The series of Wellons and associates" is also depicted.
Fig. 4. Explanted Kay-Shiley mitral prosthesis illustrating thrombuson ventricular aspect of the occluder disc. other 15 had grooved disc s , yellow discoloration of the occluder disc , and clot on the disc . Three of these 15 also had clot on the sewing ring or the struts . Disc thrombus was primarily white and usually located on the ve ntricular aspect of the disc (Fig . 4). Sixteen of the 18 patients underwent mitral valve replacement alone. One other patient underwent replacement of the mitral prosthe sis and the native tricuspid valve . The final patient unde rwent replacement of the nati ve aortic valve , but the mitral prosthesis was not rem o ved because a prom inent segment of the Kay-Sh iley sewing ring and a large block of calcium were palpable posteriorly in the
48
Bowen et al.
The Journal of Thoracic and Cardiovascular Surgery
Fig. SA. Method of fabrication of the universal valve holder from a uterine tenaculum.
Fig. SC. The universal valve holder being employed to manipulate the prosthesis during excision.
Fig. SB. Universal valve holder in vitro. atrioventricular groove . It was the surgeons' opinion that excison of the Kay-Shiley prosthesis would leave inadequate tissue posteriorly to allow rereplacement and would very likely result in subsequent atrioventricular disruption . This man had experienced one TEE , and examination of the prosthesis through the aortic
root revealed it to be free of thrombus with no significant evidence of wear. All reoperations were performed through a median sternotomy with systemic and topical hypothermia. No misadventures occurred during sternal splitting . A universal valve holder fashioned from a uterine tenaculum* (Fig . 5) facilitated exposure and manipulation of the prosthesis during excison . The Kay -Shiley prostheses were replaced with either Bjork-Shiley or porcine *Originally designed in 1966 at Walter Reed Army Medical Center by M. E. Fishback, M.D ., Augusta, Ga.
Volume 80 Number 1
MVR with Kay-Shiley prosthesis
49
July, 1980
prostheses attached with horizontal, Teflon-bolstered mattress sutures. There were four operative deaths (22%), but there have been no late deaths. One operative death resulted from myocardial infarction secondary to suture encirclement of the circumflex coronary artery. Two deaths were secondary to hemorrhage, one following posterior atrioventricular disruption and the other following irreparable superior caval laceration during decannulation. The fourth death occurred after tricuspid replacement and mitral rereplacement. This patient had tissue interference within the disc of the Bjork-Shiley valve. Death subsequently resulted from a combination of hemorrhage and low output state. Recommendations The Kay-Shiley mitral prosthesis, which enjoyed relatively wide clinical usage in the late I960s and early 1970s, is subject to moderate-to-severe occluder disc wear that can cause hang-ups of the disc occluder on the Stellite struts and can produce catastrophic failure. The TEE rate of 28.7 embolic episodes per 1,000 patient-months at risk is unacceptably high. The incidence of TEEs does not level off after a "wear in" period with this prosthesis, but continues in a straight line over the entire period of implantation. Because of the foregoing, we recommend replacement of KayShiley mitral prostheses in all patients in whom reoperation can be performed at a reasonable risk. Reoperation in 18 of 26 long-term survivors in this series revealed that only three valves were essentially normal with regard to disc wear, disc discoloration, and presence of thrombus. The other 15 prostheses had at least moderate disc wear plus gross yellow discoloration of the disc and loosely adherent thrombus on the disc and/or sewing ring and struts. The reoperative mortality rate was 22%. REFERENCES Kay JH, Kawashima Y, Kagawa Y, Tsugi HK, Redington JV: Experimental mitral valve replacement with a new disc valve. Ann Thorac Surg 2:485-498, 1966 2 Lefrak EA, Starr A: Cardiac valve prostheses, New York, 1979, Appleton-Century-Crofts, pp 167-180 3 Wellons HA, Strauch RS, Nolan SP, Muller WH: Isolated mitral valve replacement with the Kay-Shiley disc valve. Actuarial analysis of the long-term results. J THORAC CARDIOVASC SURG 70:862-868, 1975 4 Anderson RP, Bonchek LI, Grunkemeier GL, Lambert LE, Starr A: The analysis and presentation of surgical results by actuarial methods. J Surg Res 16:224-230, 1974
Reviewer's comment I am pleased that the JOURNAL is publishing this article by Bowen, Zajtchuk, Brott, and deCastro, since it points out a number of factors that are extremely important in mitral valve operations. I noted that 32 of their 80 patients had mitral insufficiency. Our belief for many years has been that the majority of patients with pure mitral insufficiency should have mitral valve repair rather than replacement. There are several advantages to mitral valve repair for mitral insufficiency. The incidence of reoperation is less with repair than with replacement, no matter what prosthesis is used. There are fewer peripheral emboli and there is no need for long-term anticoagulant therapy with repair. Thirteen of 40 late deaths in their series were due to hemorrhagic complications following sodium warfarin therapy. With mitral valve repair for mitral insufficiency, anticoagulant therapy can be discontinued in 3 months and should not be used after that. In the article by Bowen, Zajtchuk, Brott, and deCastro, the disc valve was inserted in a supra-annular position. Five of the 18 patients had a periprosthetic leak, for an incidence of 28%. We have found that periprosthetic leak can be virtually eliminated by sewing the prosthetic valve in the subannular position. Our first article on the Kay-Shiley disc valve was published in 1966. However, in an article in Archives of Surgery (98:626-628, 1969) we stressed the importance of using the muscle guard for the prosthesis whenever a disc valve is used in the mitral area. This report was followed in 1974 by an article in THE JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY (68: 30-36, 1974) on a comparative experimental study with the Starr-Edwards ball valve, the Beall disc valve, and the Kay-Shiley disc valve with a muscle guard. This article pointed out the importance of using a muscle guard whenever a prosthetic valve is used in the tricuspid area. The muscle guard is extremely important in that it prevents the muscle from encroaching on a poppet, whether it be a ball or disc. Without a muscle guard, a disc may be captured by the surrounding muscle and, as a consequence, will act as if it were hinged. Grooves then occur on the poppet where the disc moves against the struts. If captured by the muscle, the disc cannot move up and down therefore, clotting and increased thromboembolization occur. In a forthcoming publication of The Annals of Thoracic Surgery, our 13 years of experience with the Kay-Shiley disc valve with a muscle guard for tricuspid replacement in Ebstein's anomaly will be presented. There has been one death in the early postoperative period, resulting from arrhythmia. The other 12 patients are long-term survivors with no complications. I believe there is still not a perfect valve for the mitral area, and I would like to stress the extreme importance of repairing the mitral valve whenever possible. Jermoe Harold Kay, MD. Los Angeles, Calif.