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Single valve replacement with the Beall mitral prosthesis
Single valve replacement with the Beall mitral prosthesis The Beall valve is a satisfactory prosthesis for obtaining good clinical improvement in patients undergoing mitral valve replacement. A high incidence of early hemolysis is found which can usually be controlled by the administration of iron and folic acid. A low incidence of thromboembolism in anticoagulated patients has been observed. High mean diastolic gradients are noted at rest. They increase with exercise but do not interfere with clinical improvement. A significant number of these patients will show clinical deterioration primarily due to myocardial disease. Disc variance occurs in the Teflon discs in the early Model 104 Beall prosthesis and is a source of concern to us at this time; the complication has been noted in 3 patients and probably exists in a fourth. The mortality rate for mitral valve surgery can be reduced by operating upon the patients before there is marked myocardial deterioration and by correcting other problems at the same time in other valve areas and in the coronary arterial system.
N. P. Rossi, M.D., C. Kongtahworn, M.D. (by invitation), and J. L. Ehrenhaft, M.D., Iowa City, Iowa
Since the first successful mitral valve replacement in 1960, various types of prostheses have been introduced and have been improved to overcome the problems associated with them. The major problems encountered are thromboembolism, hemolysis, wearing and dysfunction of the prosthesis, infection, and hemodynamic disadvantages related to design. In 1965, Beall and colleagues! introduced a low-profile disc prosthesis which was aimed at reducing the incidence of thromboembolic complications by eliminating the interface between the sewing ring and metal seat so that after encapsulation only the compressed Teflon disc and the Teflon-coated titanium cage were exposed to blood. Early in 1968, the thickness and compression of the Teflon disc and the Teflon coating of the titanium posts were doubled. Shortly thereafter, the orifice area was increased by approximately 20 per cent From the Division of Thoracic and Cardiovascular Surgery. Department of Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242. Read at the Fifty-third Annual Meeting of The American Association for Thoracic Surgery, Dallas, Texas, April 16, 17, and 18, 1973.
and the frustrum area by approximately 25 per cent in the smaller sizes. At the University of Iowa, the first Beall prothesis was implanted in November of 1967 by the senior author. Since that time, we have been able to achieve 100 per cent follow-up on 100 patients with single mitral valve replacements with the Beall prosthesis. In this study, the minimum period of follow-up was 1 year and the longest was 5 years. Materials and methods The ages of the patients ranged from 10 to 69 years. Two of the patients were in the pediatric age group, whereas the majority was in the fourth to the sixth decades of life. Eighty-eight patients had chronic atrial fibrillation prior to operation. There were 61 females and 39 males. Eighty per cent of the patients had mitral rheumatic disease, and 20 per cent had mitral valve disease of nonrheumatic origin. There were 32 patients with predominant mitral stenosis and 20 patients with predominant mitral incompetence; 48 patients had combined mitral stenosis and incompetence. In the nonrheumatic group, 15 had spontaneous rupture of the
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chordae tendineae (2 due to subacute bacterial endocarditis), and 5 had mitral incompetence on the basis of papillary muscle dysfunction after myocardial infarction. There were 65 patients with pure mitral valve disease. In 35 patients, one or two other valves were involved but were not thought to be damaged enough to be replaced. Twenty of these had aortic valve disease, 6 tricuspid, and 9 had combined aortic and tricuspid valve disease. Twenty-four patients had previous mitral surgery. Three patients had two previous commissurotomies, 5 had three previous commissurotomies, and 16 patients had a single closed procedure. Five patients died in the immediate postoperative period, and an additional 12 died within 30 days of the operation. Eighty-three patients were therefore followed from I month to 5 years after surgery. The valve was replaced with a small prosthesis in 19, a medium valve in 48, and a large prosthesis in 33. All of the prostheses in the series were Model 104. The approach was through either a left thoracotomy or a median sternotomy. The prostheses were seated in the supra-annular position and secured with interrupted or mattress sutures of 0-0 Tevdek. Anticoagulation was started with Coumadin on the third postoperative day in all cases, and the level of the prothrombin time was maintained at twice normal. The patients were followed after discharge on at least a yearly basis in the Cardiology Clinic unless they were referred sooner by their local physicians. Results Early complications. Six patients had excessive bleeding within the first 24 hours after valve replacement and required reexploration. Bleeding was surgical in all instances and was controlled without any deaths. A low cardiac output syndrome was of major consequence in 9 patients, who required vasopressor agents for more than 24 hours in the immediate postoperative period. While rhythm disturbances were the rule in these patients, only 5 had cardiac arrhythmias that were life threatening. In 5 patients renal
failure was a serious postoperative problem requiring dialysis. Two of these patients died of renal failure. Late complications. Three patients developed bacterial endocarditis. One patient was admitted to the hospital 8 months postoperatively with a cerebrovascular accident and sepsis. A murmur of mitral insufficiency was noted. The infection was controlled, and the patient eventually was discharged with a minimal neurological deficit. Later, 28 months after the operation, she was readmitted with recurrence of the bacterial endocarditis and worsening of the mitral insufficiency; she died shortly after admission. The second patient has been doing well for over a year after the control of the infection and 18 months after the operation. The third patient developed bacterial endocarditis 2 years after the operation. It was controlled. She was admitted to the hospital 4 years after operation with a recurrence of the infection. Five patients suffered from hepatitis during the first 6 months of the postoperative period; all recovered. In 6 patients, a paravalvular leak has been proved. We reoperated upon 2 of them, and the leak was satisfactorily repaired. Another had an unsuccessful replacement of the valve along with the aortic and the tricuspid valves at another institution. The fourth patient was reoperated upon successfully in another insituation. Two patients have minimal leaks, have refused operation, and are in stable condition. Nineteen patients were referred back to the Cardiology Clinic because of anemia. In all of these patients the anemia was caused by traumatic, intravascular hemolysis. In all, at the time of our evaluation, the hemolysis was thought to be mild according to the criteria of Crexells and colleagues": a serum lactic dehydrogenase (SLDH) of 50 to 1,500 units, a free plasma hemoglobin of less than 50 mg. per 100 c.c., absence of urinary hemoglobin, and a reticulocyte count of less than 10 per cent. The anemia was corrected by the administration of iron and folic acid. Their hematocrit valves rose to acceptable levels and became stable. None of these patients was thought
Volume 67
Beall mitral prosthesis
Number 1
85
January, 1974
Table I. Hospital mortality rate including operating room deaths (up to 6 hours after operation) Diagnosis
Class
Procedure
Cause of death and autopsy findings
IV
Mitral replacement
III
Mitral replacement
III
Mitral replacement
Mitral stenosis and mitral insufficiency
IV
Mitral replacement
Mitral insufficiency, rupture of chordae
IV
Mitral replacement, coronary bypass
Acute ventricular failure, prosthesis injury to septum Cardiac failure, multiple healed infarcts of left ventricle Left ventricular failure, hemorrhage around circumflex artery Sudden death 6 hours postoperatively, carcinoma of cecum with liver spread, coronary artery disease Sudden death, no autopsy
Mitral stenosis and mitral insufficiency Mitral stenosis and coronary disease Mitral stenosis
to have paravalvular leaks by clinical examination, by phonocardiography, or in a few cases by repeat cardiac catheterization. However, 2 patients have received transfusions by their local physicians. Once present, the hemolysis can persist over long periods of time. Disc variance was noted in 2 patients. One died 44 months after operation in severe congestive heart failure and chronic pancreatitis due to alcoholism. His valve was also competent but showed changes in the valve disc. Another patient, a 35-yearold woman, developed hemolysis, a changing murmur, and clinical deterioration 50 months after replacement. The prosthesis was removed and showed severe wearing of both the disc and the legs of the cage. In another patient, the combination of hemolysis and changing murmur has developed and may indicate the existence of disc variance. Most of the patients showed clinical improvement after the operation. Of 9 patients in Class II preoperatively, 6 progressed to Class 1. Of 26 patients in Class III, 11.5 per cent remained in that category while 38.5 per cent moved up to Class II and 34.6 per cent to Class 1. Of 65 patients in Class IV, 4.6 per cent remained in that category while 57 per cent moved up to Class III, 4.6 per cent Class II, and 12.3 per cent to Class I (Fig. 1). The over-all mortality rate was 15.4 per cent in Class III patients and 21.5 per cent in Class IV patients. However, in the 5 year period on the
-
100
...'c::"
c:::J EHH8
80
~ ~
~ ~ 60
MORTALITY
I ]I
m:
POSTOP. CLASS
65
%
Ilr
....l:I
...
~
40 20 NONE
I Fig. 1. Early postoperative improvement in New York Heart Association classification after mitral replacement with Model 104 Beall prosthesis.
basis of clinical observation and evaluation, it was felt that one third of the surviving patients showed some degree of deterioration. Fourteen had repeat catheterizations, and 7 of these showed progressive myocardial dysfunction. These studies were not done to assess the hemodynamic function of the prosthesis, but high resting gradients were noted in most of these patients. Deaths. Five patients died within 6 hours after the operation (Table I). Two of these died in the operating room, one from a prosthetic injury to the septum and the second from infarction and cardiac failure due to hemorrhage around the circumflex coronary artery. One patient died suddenly after mitral valve replacement and coronary artery bypass grafting. Another patient in severe cardiac failure in the immediate post-
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Thoracic and Cardiovascular Surgery
Table II. Hospital deaths between 1 day and 1 month from operation Cause of death and autopsy findings
Diagnosis
Low cardiac output, myocardial infarction, no autopsy Low cardiac output, no autopsy
Mitral stenosis, recurrent
IV
day
Mitral stenosis and insufficiency, recurrent Mitral stenosis and insufficiency, recurrent
IV
day
IV
day
Mitral stenosis, aortic stenosis and insufficiency, tricuspid stenosis and insufficiency
IV
1 day
Mitral stenosis, tricuspid stenosis and insufficiency Mitral stenosis and insufficiency, aortic stenosis and insufficiency
III
day
IV
Mitral stenosis
III
2
Mitral stenosis, recurrent
IV
3
Mitral insufficiency Mitral stenosis and insufficiency, aortic insufficiency, tricuspid insufficiency Mitral stenosis, aortic insufficiency, tricuspid insufficiency Mitral insufficiency, aortic insufficiency
IV IV
4 5
IV
12
Arrhythmia, hematoma constricting right coronary, posterior mediastinal hematoma, subendocardial infarction, aortic stenosis Renal failure, pancreatitis, jaundice, and days hepatic necrosis Low cardiac output, cardiac cirrhosis, myodays cardial fibrosis days Respiratory failure, bleeding, no autopsy days Low cardiac output, ventricular failure, cor bovinum, total hemorrhagic necrosis in heart, brain petechiae Severe jaundice, liver and kidney failure, cor days bovinum, severe pneumonia month Congestive heart failure, no autopsy
Cerebral edema, low cardiac output, giant left atrium, severe fibrosis of lungs, cirrhosis of liver Arrhythmia, unicuspid aortic valve with stenosis, myocardial fibrosis and recent hemorrhage, severe pulmonary fibrosis, massive gastrointestinal hemorrhage Arrhythmia, no autopsy
day
IV
operative period was shown to have multiple healed infarcts and fibrosis throughout his left ventricle. The fifth patient was also shown to have coronary artery disease and in addition had carcinoma of the cecum with hepatic metastasis. Twelve patients died within 30 days of the operation (Table II). The most significant problems here were myocardial failure, arrhythmias, and complicating renal and pulmonary factors. Three patients died from thromboembolic complications. In 1 patient the embolus occurred 3 days postoperatively; it was located in the superior mesenteric artery and produced extensive small bowel gangrene. She died in 30 days. The second patient died of extensive embolization 3 months after leaving the hospital. Clot was found on the valve at autopsy. The third patient, who had had several cerebral emboli prior to operation, had cerebral and peripheral emboli at 3, 6,
and 13 months and died of pulmonary complications at 16 months. No thrombotic occlusion of the valve was seen. In the period 1 month to 5 years after operation, 14 additional patients have died (Table III). Eight died from myocardial failure, 1 from arrhythmia, 1 after a triple valve replacement, and 1 in an automobile accident. Of those dying from primary cardiac causes, all were originally in Classes III or IV. Discussion
The initial mortality rate of 5 per cent and the 30 day mortality rate of an additional 12 per cent represent a high death rate. The factors contributing to this are long-standing disease in most patients, the predominant number of patients in Classifications III and IV, the high incidence (24 per cent) of previous mitral valve surgery,
Volume 67
Beall mitral prosthesis
Number 1
87
January, 1974
Table III. Late deaths between 1 month and 5 years from operation Diagnosis
Class
Clinical problems
Time of death
31 days
Mitral stenosis
IV
Mitral stenosis, tricuspid stenosis and insufficiency Mitral insufficiency
IV
5 weeks
III
2 months
Mitral stenosis and insufficiency Mitral stenosis
III
2 months
Mitral insufficiency
III
6 months
Mitral stenosis and insufficiency, tricuspid insufficiency Mitral stenosis
III
9 months
IV
III
Renal and hepatic failure, sepsis
I
Pneumonitis, small bowel obstruction
Stroke
3 months
Bronchopneumonia, congestive failure, splenic infarcts seen on autopsy 20 months Congestive heart failure, no autopsy 26 months Severe congestive failure, died after triple valve replacement
III
Mitral stenosis and insufficiency, aortic insufficiency Mitral stenosis and insufficiency Mitral stenosis, moderate aortic insufficiency
III
Stroke at 8 months, sub- 28 months acute bacterial endocarditis, myocardial infarct, calcific aortic stenosis 33 months Hemolysis, 2 years
III
36 months
III
III
Congestive failure
and the presence of other valvular disease and coronary artery disease. As in the series of Levine and co-workers," including 100 patients followed since 1961 after mitral valve replacement with a Starr-Edwards prosthesis, the most important determinant of long-term survival is the preoperative classification of the patients. The greatest operative and late mortality rates are seen in Class IV patients. Correction of all other significant lesions should be carried out. It
Superior mesenteric embolism, massive resection of small bowel 3 days after replacement Died suddenly at home, no autopsy Congestive heart failure, no autopsy Arrhythmia, cardiac arrest, no autopsy Autopsy revealed extensive embolization Congestive heart failure, no autopsy Congestive heart failure, no autopsy
16 months
Mitral stenosis and insufficiency Mitral stenosis and insufficiency, tricuspid insufficiency, moderate aortic insufficiency Mitral stenosis
IV
Cause of death and autopsy findings
Embolism, subacute bacterial endocarditis, mitral insufficiency Congestive heart failure, no autopsy Automobile accident
44 months Autopsy showed evidence of
severe congestive failure and pancreatitis (alcoholism), considerable disc variance
is interesting to note that since July 1, 1972, in an equal number of patients operated upon for mitral valve disease, there has been a greater number of multivalvular replacements associated with coronary artery bypass grafting, with an operative mortality rate of around 5 per cent. Though clinical deterioration has been noted in one third of the surviving patients, comparison with our untreated groups shows a considerable salvage rate (Fig. 2).
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Rossi, Kongtahworn, Ehrenhait
Table IV. Embolism after single valve replacement with the Beall mitral prosthesis Patient
Anticoagulated
L. D.
No
AF
3 days
G. C.
Yes
AF
3 months
R. D.
Yes
AF
3,6, and 13 months
Superior mesenteric Cerebral and peripheral Cerebral and peripheral
E. H.
Yes No
AF AF
9 months 1 day
Cerebral Cerebral
Yes No (stopped) No (stopped)
AF AF AF
24 months 54 months 36 months
Cerebral Cerebral Cerebral
K. C.
F. D. M. H.
S. C.
t
Rhythm
Time
t
Site
Outcome Died 1 month postoperatively Died Had emboli preoperatively; died at 16 months of pulmonary complications Minimal residual Recovery; died after 18 months of self neglect Minimal residual No residual Aphasic
Legend: AF, Atrial fibrillation.
100"10
..... ~
.~
99
NORMAL POPULATION
98
80
~
.....~
1i .... i ~
~
90
b.
60
0lI!~ PATIENTS WITH MITRAL VALVE DISEASE NOT TREATED SURGICALLY
40 20
0
2
3
Years
4
5
Fig. 2. Late survival after isolated mitral valve replacement with a Beall prosthesis (Model 104).
Thromboembolism has been the major problem with prosthetic valves since their inception and has been reported to be the major cause of death. Beall valves have earned the reputation of having a markedly reduced incidence of embolism. Stanford's group" has shown in certain populations where anticoagulation is difficult to control that the valve can be used without postoperative anticoagulants with a low incidence of embolization. Javier and associates" found an incidence of 0.02 emboli per patient per month in nonanticoagulated patients with a Beall prosthesis, as compared to 0.005 in the anticoagulated group. They are recommending anticoagulant therapy for an indefinite period on the basis of this experience. Beall and co-workers! feel· that
(89.9%)
80
Q1:~
~
II)
100
~~ ~~ ~~
- _ _-o-..:BE=A::L;L PROSTHESIS
l(
70 60 I
,
,
12
24
Jj
,
Ij8 MONTHS SINCE OPERATION
, /D
Fig. 3. Actuarial analysis of the incidence of embolism after mitral replacement with Model 104 Beall prosthesis.
anticoagulation is not necessary and report an incidence of 4.5 per cent regardless of anticoagulation. In our series, the incidence of thromboembolic phenomena was 8.4 per cent (8 of 95 patients) (Table IV). All of these patients had atrial fibrillation. The most serious episodes occurred within 3 months of the operation and the three deaths were within the first year. In most instances, the site of embolization was central, but the residual deficits were frequently slight or absent, as in the general experience. If the danger is less with the passage of time, it still remains a persistent threat. There were three instances of late embolization in 3 patients at 24, 36, and 54 months; a serious neurological deficit resulted in 1 of them. One occurred at 24 months in an anticoagulated patient. In two instances the embolization occurred after anticoagulation had been stopped: in 1 patient 54 months after mitral
Volume 67 Number 1
Beall mitral prosthesis
89
January, 1974
replacement and 2 years after discontinuation of anticoagulation because of dysfunctional uterine bleeding; in the other within a few weeks after stopping anticoagulation because of imminent gallbladder surgery. The dangers of anticoagulation have been stressed, as have the dangers of discontinuing anticoagulants abruptly. Though we have seen complications of anticoagulation in other patients, in this group we have been fortunate in not encountering this problem. We are presently continuing the policy of anticoagulation in our patients with prosthetic mitral valves. Actuarial data on our patients representing 2,809 patient months indicate that there was 92.6 per cent freedom of emboli at 12 and 24 months, 91.3 per cent freedom of emboli at 36 and 48 months and 89.9 per cent freedom of emboli at 60 months (Fig. 3). A high incidence of hemolysis has been reported with the Beall prosthesis.v 6 If the criteria of the severity of the hemolysis as outlined by Crexells' group" are used, most of our patients would be classified as having mild hemolysis. This means that they have an SLDH activity of no more than 1,500 units, a free plasma hemoglobin of less than 50 mg. per 100 c.c., no urinary hemoglobin, a reticulocyte count not greater than 10 per cent, the absence of schistocytes, and a plasma total bilirubin of no more than 3 mg. per 100 c.c. The rest of them were administered iron and folic acid and are maintaining stable hematocrit values, an average reticulocyte count of 3 per cent, and absence of free plasma iron and urinary hemosiderin. The haptoglobin level, however, remains low, and the SLDH activity is slightly elevated. Platelet counts remain within normal limits. The studies of Crexells,? Williams," Walsh,' Myhre and Dale," and their colleagues indicate that the causes for this hemolysis depend upon many factors, some of which are turbulence, the functional orifice of the prosthesis, the materials employed, and the location of the prosthesis. Crexells and co-workers- felt that the material, particularly Teflon, is of greater importance than the location, the turbulence,
of even paravalvular leakage. Williams and associates," on the basis of their own observations and those of Magovern," Sayed,"? and their colleagues, suspects that the Dacron velour covering of the Beall prosthesis is the cause of the hemolysis. Williams' group" believed that since no specific hemodynamic advantages were obtained by this prosthesis, its predisposition to excessive hemolysis (72 per cent of 18 patients with no leakage or dysfunction) will limit its usefulness despite its low incidence of embolization. In our patients who developed paravalvular leakage, hemolysis was severe in 2 and was rectified with correction of the leakage. In 2 patients with small paravalvular leaks who were being followed, hemolysis has not been excessive. In 1 patient, hemolysis appeared late, along with changing murmurs and clinical deterioration. This patient showed marked disc variance requiring reoperation. We are following another patient with similar findings who has not as yet been operated upon. We have noted disc variance in 1 other patient in whom no valvular incompetence was present. Robinson and associates': noted disc variance at autopsy in most patients with Beall valves manufactured before 1968. Nichols and associates," studying 273 patients who survived after mitral replacement with the Beall valve, noted disc variance in only 1 patient. Vogel's group'? followed 29 patients with the Beall prosthesis for an average of 44 months. In 9 of these patients, repeat catheterization was carried out between 10 and 20 months after operation. Although in most of these patients there was uniformly good-to-excellent improvement in the clinical status, persistent hemodynamic abnormalities were noted. Functional obstruction persisted, as evidenced by a significant mean diastolic gradient which increased with exercise. Ramsey and colleagues':' found improvement in pulmonary artery pressure, pulmonary arterial wedge pressure, pulmonary vascular resistance, left atrial pressure, and cardiac index after mitral valve replacement in 23 patients. He also found a significant mean diastolic gradient across the
The Journal of
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Rossi, Kongtahworn, Ehrenhajt
Thoracic and Cardiovascular Surgery
Table V. Catheterization data in 14 patients with Model 104 Beall prosthesis Preoperative
Patient (age, sex)
Pulmonary Cardiac artery index (L./ pressure min./sq. M.) (mm. Hg)
Pulmonary artery wedge (mm. Hg)
Mean diastolic gradient (mm. Hg)
Valve area* (sq. em.)
Ejection fraction
Prosthetic valve size
Months between cath.
1.5
22
17
7.6
M
46
1.7
25
18
16.0
L
36
1.3
23
20
15.0
M
30
2.5
26
18
9.0
L
40
2.2
25
11
5.0
L
24
I. M. (50, F)
1.8
21
21
8.0
M
30
1. G. (31, M) J. H. (40, F) R. W. (52, M) E. D. (30, F) L. W. (49, M) R. S. (45, M)
2.8
22
16
9.0
L
12
2.4
22
18
10.0
M
36
2.5
19
12
9.5
L
12
1.6
51
34
12.7
M
40
1.0
22
22
9.1
0.6
0.54
M
32
2.0
32
24
14.0
1.5
0.38
M
12
G. (54, H. (52,
2.1
36
31
16.0
0.7
0.81
M
22
1.7
27
18
11.0
1.0
L
48
L. M. (38, M) G. B. (52, M) L.B. (49, F) G. K. (54, M) C. P. (56, M)
Y. F)
A. M)
'Actual valve area-medium - 3.24 sq. em. and large - 4.11 sq. em.
valve in their series averaging 7.5 ± 1.6 mm. Hg at rest and rising to 12.5 ± 2.3 mm. Hg with exercise. Although one would expect an increase in the mean diastolic gradient across the valve with an increase in cardiac index, several patients in Ramsey's series were found to have significantly high gradients across the prosthesis in patients who had a marked reduction of cardiac index. Very similar findings have been reported by Reid," Linhart, Iii and their co-workers. We have had the opportunity to obtain postoperative catheterization data on 14 of our patients (Table V). These studies were not done to assess the hemodynamic function of
the valve but usually had some clinical indication, the most common of which was deterioration of the patient's clinical status. Six of the 14 patients did indeed show marked myocardial deterioration, as judged by cineventriculography and low ejection fractions at the time of the second catheterization. Lower diastolic gradients were found in those patients with poor ventricular function. None of these patients was tested during exercise. Three other patients who had good myocardial function were so tested, and the mean diastolic gradient rose to 12, 24, and 24 mm. Hg, respectively. In all cases, the calculated valve area was con-
Volume 67
Beall mitral prosthesis
Number 1 Jonuory, 1974
9 1
Postoperative Cardiac Pulmonary Pulmonary Mean index artery artery diastolic Valve wedge gradient Ejection (L.lmin.! pressure area sq. M.) (mm, Hg) (mm, Hg) (mm, Hg) (sq. em.) fraction
0.29 2.0
0.30
Marked deterioration in left ventricular function
2.0
0.23
Massive myocardial infarction due to bacterial endocarditis; progressive deterioration after replacement Developed severe tricuspid insufficiency and progression of aortic insufficiency; small paravalvular leak Repair of paravalvular leak; postoperative data after second operation Previous commissurotomy at age 24 years; increasing dyspnea in past year Hemolysis; gradient rose to 24 mm. Hg on exercise Marked disc variance
46
28
6.0
1.1
0.39
1.5
39
27
10.0
1.3
0.23
1.5
20
15
4.0
3.1
44
22
8.0
2.1
16
10
3.5
22
0.0
0.20 0.68
0.9
Remarks: Indications for recath.
Very poor left ventricular function preoperatively; no improvement postoperatively Poor left ventricular function; no improvement postoperatively Progressive clinical deterioration
1.6
2.7
30
28
7.0
2.0
18
14
8.0
1.5
0.69
2.3
13
8
4.6
3.3
0.65
3.3
38
24
16.0
1.5
0.61
1.9
15
II
6.4
1.6
0.50
2.7
24
I2
11.0
1.2
2.2
28
20
12.0
2.1
20
12
5.0
0.61 2.7
siderably lower than the actual area given for the respective valves. REFERENCES Beall, A. C., Jr., Bricker, D. L., and Messmer, B. 1.: Results of Mitral Valve Replacement With Dacron Velour-Covered Teflon-Disc Prosthesis, Ann. Thorac. Surg. 9: 195, 1970. 2 Crexells, c., Aerichide, N., Bonny, Y., Lepage, G., and Campeau, L.: Factors Influencing Hemolysis in Valve Prosthesis, Am. Heart J. 84: 161, 1972. 3 Levine, F. H., Copeland, J. G., and Morrow, A. G.: Prosthetic Replacement of the Mitral Valve: Continuing Assessments of the 100 Patients Operated Upon During 1961-1965, Circulation 47: 518, 1973.
0.51
No clinical improvement; gradient 6.4 mm. Hg on exercise Poor left ventricular function preoperatively; no change in classification postoperatively; gradient increased to 24 mm. Hg on exercise Hemolysis; suspected paravalvular leak Anemia and hemolysis requiring treatment 4 years postoperatively
4 Stanford, W., Lindberg, E. F., and Armstrong, R. G.: Implantation of Heart Valve Prostheses Without Anticoagulants, J. THORAC. CARDIOVASCo SURG. 63: 648, 1972. 5 Javier, R. P., Hildner, F. J., Berry, W., Greenberg, J. J., and Samet, P.: Systemic Embolism and the Beall Mitral Valve Prosthesis, Ann. Thorac. Surg. 10: 20, 1970. 6 Williams, J. C., Jr., Vernon, C. R., Daicoff', G. R., Bartley, T. D., Wheat, M. W., Jr., and Ramsey, H. W.: Hemolysis Following Mitral Valve Replacement With the Beall Valve Prosthesis, J. THORAC. CARDIOVASC. SURG. 61: 393, 1971. 7 Walsh, J. R., Starr, A., and Ritzmann, L. W.: Intravascular Hemolysis in Patients With Prosthetic Valves and Valvular Heart Disease, Circulation 39, 40: 135, 1969 (SuppI. I).
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Rossi, Kongtahworn, Ehrenhait
Surgery
8 Myhre, E., and Dale, J.: Hemolysis in Mitral Valvular Disease and Mitral Ball Valve Prostheses, Acta Med. Scand. 189: 547, 1971. 9 Magovern, G. J., Begg, F. 1., Kent, E. M., Cushing, W. B., Gerber, M. L., and Fisher, D. L.: The Experimental and Clinical Results of a Modified Cage Disc Mitral Prosthesis, J. THORAC. CARDIOVASC. SURG. 59: 109, 1970. 10 Sayed, H. M., Dacie, J. V., Hanaley, D. A., Lewis, S. M., and Cleland, W. P.: Hemolytic Anemia of Mechanical Origin After Open Heart Surgery, Thorax 16: 335, 1961. 11 Robinson, M. J., Hildner, F. J., and Greenberg, J. J.: Disc Variance of Beall Mitral Valve, Ann. Thorac. Surg. 11: 11, 1971. 12 Nichols, H. T., Fernandez, J., Morse, D., and Gooch, A. S.: Improved Results in 336 Patients With the Isolated Mitral Beall Valve Replacement, Chest 62: 266, 1972. 13 Vogel, J. H. K., Paton, B. C., Overy, H. R., Pappas, G., Davies, H., and Blount, S. G.:
Advantages of the Beall Valve Prosthesis, Chest 59: 249, 1971. 14 Ramsey, H. W., Williams, J. C., Jr., Vernon, C. R., Wheat, M. W., Daicoff, G. R., and Bartley, T. D.: Hemodynamic Findings Following Replacement of the Mitral Valve With the Beall Valve Prosthesis, J. THORAC. CARD10VASC. SURG. 62: 624, 1971. 15 Reid, J. A., Stevens, T. W., Sigwart, D., Fulweber, R. C., and Alexander, J. K.: Hemodynamic Evaluation of the Beall Mitral Valve Prosthesis, Circulation 45, 46: 1, 1972 (Supp\. I).
16 Linhart, J. W., Barold, S. S., Hildner, F. J., Samet, P., Piccinini, J. C., Marsten, J. L., and Greenberg, J. J.: Clinical and Hemodynamic Findings Following Replacement of the Mitral Valve With a Beall Valve Prosthesis (Dacron Velour-Covered Teflon-Disc Valve), Circulation 49, 50: 127, 1969 (Suppl. I). (For Discussion, see page 106)
N. P. Rossi, M.D., C. Kongtahworn, M.D. (by invitation), and J. L. Ehrenhaft, M.D., Iowa City, Iowa
Since the first successful mitral valve replacement in 1960, various types of prostheses have been introduced and have been improved to overcome the problems associated with them. The major problems encountered are thromboembolism, hemolysis, wearing and dysfunction of the prosthesis, infection, and hemodynamic disadvantages related to design. In 1965, Beall and colleagues! introduced a low-profile disc prosthesis which was aimed at reducing the incidence of thromboembolic complications by eliminating the interface between the sewing ring and metal seat so that after encapsulation only the compressed Teflon disc and the Teflon-coated titanium cage were exposed to blood. Early in 1968, the thickness and compression of the Teflon disc and the Teflon coating of the titanium posts were doubled. Shortly thereafter, the orifice area was increased by approximately 20 per cent From the Division of Thoracic and Cardiovascular Surgery. Department of Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242. Read at the Fifty-third Annual Meeting of The American Association for Thoracic Surgery, Dallas, Texas, April 16, 17, and 18, 1973.
and the frustrum area by approximately 25 per cent in the smaller sizes. At the University of Iowa, the first Beall prothesis was implanted in November of 1967 by the senior author. Since that time, we have been able to achieve 100 per cent follow-up on 100 patients with single mitral valve replacements with the Beall prosthesis. In this study, the minimum period of follow-up was 1 year and the longest was 5 years. Materials and methods The ages of the patients ranged from 10 to 69 years. Two of the patients were in the pediatric age group, whereas the majority was in the fourth to the sixth decades of life. Eighty-eight patients had chronic atrial fibrillation prior to operation. There were 61 females and 39 males. Eighty per cent of the patients had mitral rheumatic disease, and 20 per cent had mitral valve disease of nonrheumatic origin. There were 32 patients with predominant mitral stenosis and 20 patients with predominant mitral incompetence; 48 patients had combined mitral stenosis and incompetence. In the nonrheumatic group, 15 had spontaneous rupture of the
83
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Thoracic and Cardiovascular Surgery
chordae tendineae (2 due to subacute bacterial endocarditis), and 5 had mitral incompetence on the basis of papillary muscle dysfunction after myocardial infarction. There were 65 patients with pure mitral valve disease. In 35 patients, one or two other valves were involved but were not thought to be damaged enough to be replaced. Twenty of these had aortic valve disease, 6 tricuspid, and 9 had combined aortic and tricuspid valve disease. Twenty-four patients had previous mitral surgery. Three patients had two previous commissurotomies, 5 had three previous commissurotomies, and 16 patients had a single closed procedure. Five patients died in the immediate postoperative period, and an additional 12 died within 30 days of the operation. Eighty-three patients were therefore followed from I month to 5 years after surgery. The valve was replaced with a small prosthesis in 19, a medium valve in 48, and a large prosthesis in 33. All of the prostheses in the series were Model 104. The approach was through either a left thoracotomy or a median sternotomy. The prostheses were seated in the supra-annular position and secured with interrupted or mattress sutures of 0-0 Tevdek. Anticoagulation was started with Coumadin on the third postoperative day in all cases, and the level of the prothrombin time was maintained at twice normal. The patients were followed after discharge on at least a yearly basis in the Cardiology Clinic unless they were referred sooner by their local physicians. Results Early complications. Six patients had excessive bleeding within the first 24 hours after valve replacement and required reexploration. Bleeding was surgical in all instances and was controlled without any deaths. A low cardiac output syndrome was of major consequence in 9 patients, who required vasopressor agents for more than 24 hours in the immediate postoperative period. While rhythm disturbances were the rule in these patients, only 5 had cardiac arrhythmias that were life threatening. In 5 patients renal
failure was a serious postoperative problem requiring dialysis. Two of these patients died of renal failure. Late complications. Three patients developed bacterial endocarditis. One patient was admitted to the hospital 8 months postoperatively with a cerebrovascular accident and sepsis. A murmur of mitral insufficiency was noted. The infection was controlled, and the patient eventually was discharged with a minimal neurological deficit. Later, 28 months after the operation, she was readmitted with recurrence of the bacterial endocarditis and worsening of the mitral insufficiency; she died shortly after admission. The second patient has been doing well for over a year after the control of the infection and 18 months after the operation. The third patient developed bacterial endocarditis 2 years after the operation. It was controlled. She was admitted to the hospital 4 years after operation with a recurrence of the infection. Five patients suffered from hepatitis during the first 6 months of the postoperative period; all recovered. In 6 patients, a paravalvular leak has been proved. We reoperated upon 2 of them, and the leak was satisfactorily repaired. Another had an unsuccessful replacement of the valve along with the aortic and the tricuspid valves at another institution. The fourth patient was reoperated upon successfully in another insituation. Two patients have minimal leaks, have refused operation, and are in stable condition. Nineteen patients were referred back to the Cardiology Clinic because of anemia. In all of these patients the anemia was caused by traumatic, intravascular hemolysis. In all, at the time of our evaluation, the hemolysis was thought to be mild according to the criteria of Crexells and colleagues": a serum lactic dehydrogenase (SLDH) of 50 to 1,500 units, a free plasma hemoglobin of less than 50 mg. per 100 c.c., absence of urinary hemoglobin, and a reticulocyte count of less than 10 per cent. The anemia was corrected by the administration of iron and folic acid. Their hematocrit valves rose to acceptable levels and became stable. None of these patients was thought
Volume 67
Beall mitral prosthesis
Number 1
85
January, 1974
Table I. Hospital mortality rate including operating room deaths (up to 6 hours after operation) Diagnosis
Class
Procedure
Cause of death and autopsy findings
IV
Mitral replacement
III
Mitral replacement
III
Mitral replacement
Mitral stenosis and mitral insufficiency
IV
Mitral replacement
Mitral insufficiency, rupture of chordae
IV
Mitral replacement, coronary bypass
Acute ventricular failure, prosthesis injury to septum Cardiac failure, multiple healed infarcts of left ventricle Left ventricular failure, hemorrhage around circumflex artery Sudden death 6 hours postoperatively, carcinoma of cecum with liver spread, coronary artery disease Sudden death, no autopsy
Mitral stenosis and mitral insufficiency Mitral stenosis and coronary disease Mitral stenosis
to have paravalvular leaks by clinical examination, by phonocardiography, or in a few cases by repeat cardiac catheterization. However, 2 patients have received transfusions by their local physicians. Once present, the hemolysis can persist over long periods of time. Disc variance was noted in 2 patients. One died 44 months after operation in severe congestive heart failure and chronic pancreatitis due to alcoholism. His valve was also competent but showed changes in the valve disc. Another patient, a 35-yearold woman, developed hemolysis, a changing murmur, and clinical deterioration 50 months after replacement. The prosthesis was removed and showed severe wearing of both the disc and the legs of the cage. In another patient, the combination of hemolysis and changing murmur has developed and may indicate the existence of disc variance. Most of the patients showed clinical improvement after the operation. Of 9 patients in Class II preoperatively, 6 progressed to Class 1. Of 26 patients in Class III, 11.5 per cent remained in that category while 38.5 per cent moved up to Class II and 34.6 per cent to Class 1. Of 65 patients in Class IV, 4.6 per cent remained in that category while 57 per cent moved up to Class III, 4.6 per cent Class II, and 12.3 per cent to Class I (Fig. 1). The over-all mortality rate was 15.4 per cent in Class III patients and 21.5 per cent in Class IV patients. However, in the 5 year period on the
-
100
...'c::"
c:::J EHH8
80
~ ~
~ ~ 60
MORTALITY
I ]I
m:
POSTOP. CLASS
65
%
Ilr
....l:I
...
~
40 20 NONE
I Fig. 1. Early postoperative improvement in New York Heart Association classification after mitral replacement with Model 104 Beall prosthesis.
basis of clinical observation and evaluation, it was felt that one third of the surviving patients showed some degree of deterioration. Fourteen had repeat catheterizations, and 7 of these showed progressive myocardial dysfunction. These studies were not done to assess the hemodynamic function of the prosthesis, but high resting gradients were noted in most of these patients. Deaths. Five patients died within 6 hours after the operation (Table I). Two of these died in the operating room, one from a prosthetic injury to the septum and the second from infarction and cardiac failure due to hemorrhage around the circumflex coronary artery. One patient died suddenly after mitral valve replacement and coronary artery bypass grafting. Another patient in severe cardiac failure in the immediate post-
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Rossi, Kongtahworn, Ehrenhait
Thoracic and Cardiovascular Surgery
Table II. Hospital deaths between 1 day and 1 month from operation Cause of death and autopsy findings
Diagnosis
Low cardiac output, myocardial infarction, no autopsy Low cardiac output, no autopsy
Mitral stenosis, recurrent
IV
day
Mitral stenosis and insufficiency, recurrent Mitral stenosis and insufficiency, recurrent
IV
day
IV
day
Mitral stenosis, aortic stenosis and insufficiency, tricuspid stenosis and insufficiency
IV
1 day
Mitral stenosis, tricuspid stenosis and insufficiency Mitral stenosis and insufficiency, aortic stenosis and insufficiency
III
day
IV
Mitral stenosis
III
2
Mitral stenosis, recurrent
IV
3
Mitral insufficiency Mitral stenosis and insufficiency, aortic insufficiency, tricuspid insufficiency Mitral stenosis, aortic insufficiency, tricuspid insufficiency Mitral insufficiency, aortic insufficiency
IV IV
4 5
IV
12
Arrhythmia, hematoma constricting right coronary, posterior mediastinal hematoma, subendocardial infarction, aortic stenosis Renal failure, pancreatitis, jaundice, and days hepatic necrosis Low cardiac output, cardiac cirrhosis, myodays cardial fibrosis days Respiratory failure, bleeding, no autopsy days Low cardiac output, ventricular failure, cor bovinum, total hemorrhagic necrosis in heart, brain petechiae Severe jaundice, liver and kidney failure, cor days bovinum, severe pneumonia month Congestive heart failure, no autopsy
Cerebral edema, low cardiac output, giant left atrium, severe fibrosis of lungs, cirrhosis of liver Arrhythmia, unicuspid aortic valve with stenosis, myocardial fibrosis and recent hemorrhage, severe pulmonary fibrosis, massive gastrointestinal hemorrhage Arrhythmia, no autopsy
day
IV
operative period was shown to have multiple healed infarcts and fibrosis throughout his left ventricle. The fifth patient was also shown to have coronary artery disease and in addition had carcinoma of the cecum with hepatic metastasis. Twelve patients died within 30 days of the operation (Table II). The most significant problems here were myocardial failure, arrhythmias, and complicating renal and pulmonary factors. Three patients died from thromboembolic complications. In 1 patient the embolus occurred 3 days postoperatively; it was located in the superior mesenteric artery and produced extensive small bowel gangrene. She died in 30 days. The second patient died of extensive embolization 3 months after leaving the hospital. Clot was found on the valve at autopsy. The third patient, who had had several cerebral emboli prior to operation, had cerebral and peripheral emboli at 3, 6,
and 13 months and died of pulmonary complications at 16 months. No thrombotic occlusion of the valve was seen. In the period 1 month to 5 years after operation, 14 additional patients have died (Table III). Eight died from myocardial failure, 1 from arrhythmia, 1 after a triple valve replacement, and 1 in an automobile accident. Of those dying from primary cardiac causes, all were originally in Classes III or IV. Discussion
The initial mortality rate of 5 per cent and the 30 day mortality rate of an additional 12 per cent represent a high death rate. The factors contributing to this are long-standing disease in most patients, the predominant number of patients in Classifications III and IV, the high incidence (24 per cent) of previous mitral valve surgery,
Volume 67
Beall mitral prosthesis
Number 1
87
January, 1974
Table III. Late deaths between 1 month and 5 years from operation Diagnosis
Class
Clinical problems
Time of death
31 days
Mitral stenosis
IV
Mitral stenosis, tricuspid stenosis and insufficiency Mitral insufficiency
IV
5 weeks
III
2 months
Mitral stenosis and insufficiency Mitral stenosis
III
2 months
Mitral insufficiency
III
6 months
Mitral stenosis and insufficiency, tricuspid insufficiency Mitral stenosis
III
9 months
IV
III
Renal and hepatic failure, sepsis
I
Pneumonitis, small bowel obstruction
Stroke
3 months
Bronchopneumonia, congestive failure, splenic infarcts seen on autopsy 20 months Congestive heart failure, no autopsy 26 months Severe congestive failure, died after triple valve replacement
III
Mitral stenosis and insufficiency, aortic insufficiency Mitral stenosis and insufficiency Mitral stenosis, moderate aortic insufficiency
III
Stroke at 8 months, sub- 28 months acute bacterial endocarditis, myocardial infarct, calcific aortic stenosis 33 months Hemolysis, 2 years
III
36 months
III
III
Congestive failure
and the presence of other valvular disease and coronary artery disease. As in the series of Levine and co-workers," including 100 patients followed since 1961 after mitral valve replacement with a Starr-Edwards prosthesis, the most important determinant of long-term survival is the preoperative classification of the patients. The greatest operative and late mortality rates are seen in Class IV patients. Correction of all other significant lesions should be carried out. It
Superior mesenteric embolism, massive resection of small bowel 3 days after replacement Died suddenly at home, no autopsy Congestive heart failure, no autopsy Arrhythmia, cardiac arrest, no autopsy Autopsy revealed extensive embolization Congestive heart failure, no autopsy Congestive heart failure, no autopsy
16 months
Mitral stenosis and insufficiency Mitral stenosis and insufficiency, tricuspid insufficiency, moderate aortic insufficiency Mitral stenosis
IV
Cause of death and autopsy findings
Embolism, subacute bacterial endocarditis, mitral insufficiency Congestive heart failure, no autopsy Automobile accident
44 months Autopsy showed evidence of
severe congestive failure and pancreatitis (alcoholism), considerable disc variance
is interesting to note that since July 1, 1972, in an equal number of patients operated upon for mitral valve disease, there has been a greater number of multivalvular replacements associated with coronary artery bypass grafting, with an operative mortality rate of around 5 per cent. Though clinical deterioration has been noted in one third of the surviving patients, comparison with our untreated groups shows a considerable salvage rate (Fig. 2).
88
The Journal of Thoracic and Cardiovascular Surgery
Rossi, Kongtahworn, Ehrenhait
Table IV. Embolism after single valve replacement with the Beall mitral prosthesis Patient
Anticoagulated
L. D.
No
AF
3 days
G. C.
Yes
AF
3 months
R. D.
Yes
AF
3,6, and 13 months
Superior mesenteric Cerebral and peripheral Cerebral and peripheral
E. H.
Yes No
AF AF
9 months 1 day
Cerebral Cerebral
Yes No (stopped) No (stopped)
AF AF AF
24 months 54 months 36 months
Cerebral Cerebral Cerebral
K. C.
F. D. M. H.
S. C.
t
Rhythm
Time
t
Site
Outcome Died 1 month postoperatively Died Had emboli preoperatively; died at 16 months of pulmonary complications Minimal residual Recovery; died after 18 months of self neglect Minimal residual No residual Aphasic
Legend: AF, Atrial fibrillation.
100"10
..... ~
.~
99
NORMAL POPULATION
98
80
~
.....~
1i .... i ~
~
90
b.
60
0lI!~ PATIENTS WITH MITRAL VALVE DISEASE NOT TREATED SURGICALLY
40 20
0
2
3
Years
4
5
Fig. 2. Late survival after isolated mitral valve replacement with a Beall prosthesis (Model 104).
Thromboembolism has been the major problem with prosthetic valves since their inception and has been reported to be the major cause of death. Beall valves have earned the reputation of having a markedly reduced incidence of embolism. Stanford's group" has shown in certain populations where anticoagulation is difficult to control that the valve can be used without postoperative anticoagulants with a low incidence of embolization. Javier and associates" found an incidence of 0.02 emboli per patient per month in nonanticoagulated patients with a Beall prosthesis, as compared to 0.005 in the anticoagulated group. They are recommending anticoagulant therapy for an indefinite period on the basis of this experience. Beall and co-workers! feel· that
(89.9%)
80
Q1:~
~
II)
100
~~ ~~ ~~
- _ _-o-..:BE=A::L;L PROSTHESIS
l(
70 60 I
,
,
12
24
Jj
,
Ij8 MONTHS SINCE OPERATION
, /D
Fig. 3. Actuarial analysis of the incidence of embolism after mitral replacement with Model 104 Beall prosthesis.
anticoagulation is not necessary and report an incidence of 4.5 per cent regardless of anticoagulation. In our series, the incidence of thromboembolic phenomena was 8.4 per cent (8 of 95 patients) (Table IV). All of these patients had atrial fibrillation. The most serious episodes occurred within 3 months of the operation and the three deaths were within the first year. In most instances, the site of embolization was central, but the residual deficits were frequently slight or absent, as in the general experience. If the danger is less with the passage of time, it still remains a persistent threat. There were three instances of late embolization in 3 patients at 24, 36, and 54 months; a serious neurological deficit resulted in 1 of them. One occurred at 24 months in an anticoagulated patient. In two instances the embolization occurred after anticoagulation had been stopped: in 1 patient 54 months after mitral
Volume 67 Number 1
Beall mitral prosthesis
89
January, 1974
replacement and 2 years after discontinuation of anticoagulation because of dysfunctional uterine bleeding; in the other within a few weeks after stopping anticoagulation because of imminent gallbladder surgery. The dangers of anticoagulation have been stressed, as have the dangers of discontinuing anticoagulants abruptly. Though we have seen complications of anticoagulation in other patients, in this group we have been fortunate in not encountering this problem. We are presently continuing the policy of anticoagulation in our patients with prosthetic mitral valves. Actuarial data on our patients representing 2,809 patient months indicate that there was 92.6 per cent freedom of emboli at 12 and 24 months, 91.3 per cent freedom of emboli at 36 and 48 months and 89.9 per cent freedom of emboli at 60 months (Fig. 3). A high incidence of hemolysis has been reported with the Beall prosthesis.v 6 If the criteria of the severity of the hemolysis as outlined by Crexells' group" are used, most of our patients would be classified as having mild hemolysis. This means that they have an SLDH activity of no more than 1,500 units, a free plasma hemoglobin of less than 50 mg. per 100 c.c., no urinary hemoglobin, a reticulocyte count not greater than 10 per cent, the absence of schistocytes, and a plasma total bilirubin of no more than 3 mg. per 100 c.c. The rest of them were administered iron and folic acid and are maintaining stable hematocrit values, an average reticulocyte count of 3 per cent, and absence of free plasma iron and urinary hemosiderin. The haptoglobin level, however, remains low, and the SLDH activity is slightly elevated. Platelet counts remain within normal limits. The studies of Crexells,? Williams," Walsh,' Myhre and Dale," and their colleagues indicate that the causes for this hemolysis depend upon many factors, some of which are turbulence, the functional orifice of the prosthesis, the materials employed, and the location of the prosthesis. Crexells and co-workers- felt that the material, particularly Teflon, is of greater importance than the location, the turbulence,
of even paravalvular leakage. Williams and associates," on the basis of their own observations and those of Magovern," Sayed,"? and their colleagues, suspects that the Dacron velour covering of the Beall prosthesis is the cause of the hemolysis. Williams' group" believed that since no specific hemodynamic advantages were obtained by this prosthesis, its predisposition to excessive hemolysis (72 per cent of 18 patients with no leakage or dysfunction) will limit its usefulness despite its low incidence of embolization. In our patients who developed paravalvular leakage, hemolysis was severe in 2 and was rectified with correction of the leakage. In 2 patients with small paravalvular leaks who were being followed, hemolysis has not been excessive. In 1 patient, hemolysis appeared late, along with changing murmurs and clinical deterioration. This patient showed marked disc variance requiring reoperation. We are following another patient with similar findings who has not as yet been operated upon. We have noted disc variance in 1 other patient in whom no valvular incompetence was present. Robinson and associates': noted disc variance at autopsy in most patients with Beall valves manufactured before 1968. Nichols and associates," studying 273 patients who survived after mitral replacement with the Beall valve, noted disc variance in only 1 patient. Vogel's group'? followed 29 patients with the Beall prosthesis for an average of 44 months. In 9 of these patients, repeat catheterization was carried out between 10 and 20 months after operation. Although in most of these patients there was uniformly good-to-excellent improvement in the clinical status, persistent hemodynamic abnormalities were noted. Functional obstruction persisted, as evidenced by a significant mean diastolic gradient which increased with exercise. Ramsey and colleagues':' found improvement in pulmonary artery pressure, pulmonary arterial wedge pressure, pulmonary vascular resistance, left atrial pressure, and cardiac index after mitral valve replacement in 23 patients. He also found a significant mean diastolic gradient across the
The Journal of
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Rossi, Kongtahworn, Ehrenhajt
Thoracic and Cardiovascular Surgery
Table V. Catheterization data in 14 patients with Model 104 Beall prosthesis Preoperative
Patient (age, sex)
Pulmonary Cardiac artery index (L./ pressure min./sq. M.) (mm. Hg)
Pulmonary artery wedge (mm. Hg)
Mean diastolic gradient (mm. Hg)
Valve area* (sq. em.)
Ejection fraction
Prosthetic valve size
Months between cath.
1.5
22
17
7.6
M
46
1.7
25
18
16.0
L
36
1.3
23
20
15.0
M
30
2.5
26
18
9.0
L
40
2.2
25
11
5.0
L
24
I. M. (50, F)
1.8
21
21
8.0
M
30
1. G. (31, M) J. H. (40, F) R. W. (52, M) E. D. (30, F) L. W. (49, M) R. S. (45, M)
2.8
22
16
9.0
L
12
2.4
22
18
10.0
M
36
2.5
19
12
9.5
L
12
1.6
51
34
12.7
M
40
1.0
22
22
9.1
0.6
0.54
M
32
2.0
32
24
14.0
1.5
0.38
M
12
G. (54, H. (52,
2.1
36
31
16.0
0.7
0.81
M
22
1.7
27
18
11.0
1.0
L
48
L. M. (38, M) G. B. (52, M) L.B. (49, F) G. K. (54, M) C. P. (56, M)
Y. F)
A. M)
'Actual valve area-medium - 3.24 sq. em. and large - 4.11 sq. em.
valve in their series averaging 7.5 ± 1.6 mm. Hg at rest and rising to 12.5 ± 2.3 mm. Hg with exercise. Although one would expect an increase in the mean diastolic gradient across the valve with an increase in cardiac index, several patients in Ramsey's series were found to have significantly high gradients across the prosthesis in patients who had a marked reduction of cardiac index. Very similar findings have been reported by Reid," Linhart, Iii and their co-workers. We have had the opportunity to obtain postoperative catheterization data on 14 of our patients (Table V). These studies were not done to assess the hemodynamic function of
the valve but usually had some clinical indication, the most common of which was deterioration of the patient's clinical status. Six of the 14 patients did indeed show marked myocardial deterioration, as judged by cineventriculography and low ejection fractions at the time of the second catheterization. Lower diastolic gradients were found in those patients with poor ventricular function. None of these patients was tested during exercise. Three other patients who had good myocardial function were so tested, and the mean diastolic gradient rose to 12, 24, and 24 mm. Hg, respectively. In all cases, the calculated valve area was con-
Volume 67
Beall mitral prosthesis
Number 1 Jonuory, 1974
9 1
Postoperative Cardiac Pulmonary Pulmonary Mean index artery artery diastolic Valve wedge gradient Ejection (L.lmin.! pressure area sq. M.) (mm, Hg) (mm, Hg) (mm, Hg) (sq. em.) fraction
0.29 2.0
0.30
Marked deterioration in left ventricular function
2.0
0.23
Massive myocardial infarction due to bacterial endocarditis; progressive deterioration after replacement Developed severe tricuspid insufficiency and progression of aortic insufficiency; small paravalvular leak Repair of paravalvular leak; postoperative data after second operation Previous commissurotomy at age 24 years; increasing dyspnea in past year Hemolysis; gradient rose to 24 mm. Hg on exercise Marked disc variance
46
28
6.0
1.1
0.39
1.5
39
27
10.0
1.3
0.23
1.5
20
15
4.0
3.1
44
22
8.0
2.1
16
10
3.5
22
0.0
0.20 0.68
0.9
Remarks: Indications for recath.
Very poor left ventricular function preoperatively; no improvement postoperatively Poor left ventricular function; no improvement postoperatively Progressive clinical deterioration
1.6
2.7
30
28
7.0
2.0
18
14
8.0
1.5
0.69
2.3
13
8
4.6
3.3
0.65
3.3
38
24
16.0
1.5
0.61
1.9
15
II
6.4
1.6
0.50
2.7
24
I2
11.0
1.2
2.2
28
20
12.0
2.1
20
12
5.0
0.61 2.7
siderably lower than the actual area given for the respective valves. REFERENCES Beall, A. C., Jr., Bricker, D. L., and Messmer, B. 1.: Results of Mitral Valve Replacement With Dacron Velour-Covered Teflon-Disc Prosthesis, Ann. Thorac. Surg. 9: 195, 1970. 2 Crexells, c., Aerichide, N., Bonny, Y., Lepage, G., and Campeau, L.: Factors Influencing Hemolysis in Valve Prosthesis, Am. Heart J. 84: 161, 1972. 3 Levine, F. H., Copeland, J. G., and Morrow, A. G.: Prosthetic Replacement of the Mitral Valve: Continuing Assessments of the 100 Patients Operated Upon During 1961-1965, Circulation 47: 518, 1973.
0.51
No clinical improvement; gradient 6.4 mm. Hg on exercise Poor left ventricular function preoperatively; no change in classification postoperatively; gradient increased to 24 mm. Hg on exercise Hemolysis; suspected paravalvular leak Anemia and hemolysis requiring treatment 4 years postoperatively
4 Stanford, W., Lindberg, E. F., and Armstrong, R. G.: Implantation of Heart Valve Prostheses Without Anticoagulants, J. THORAC. CARDIOVASCo SURG. 63: 648, 1972. 5 Javier, R. P., Hildner, F. J., Berry, W., Greenberg, J. J., and Samet, P.: Systemic Embolism and the Beall Mitral Valve Prosthesis, Ann. Thorac. Surg. 10: 20, 1970. 6 Williams, J. C., Jr., Vernon, C. R., Daicoff', G. R., Bartley, T. D., Wheat, M. W., Jr., and Ramsey, H. W.: Hemolysis Following Mitral Valve Replacement With the Beall Valve Prosthesis, J. THORAC. CARDIOVASC. SURG. 61: 393, 1971. 7 Walsh, J. R., Starr, A., and Ritzmann, L. W.: Intravascular Hemolysis in Patients With Prosthetic Valves and Valvular Heart Disease, Circulation 39, 40: 135, 1969 (SuppI. I).
92
The Journal of Thoracic and Cardiovascular
Rossi, Kongtahworn, Ehrenhait
Surgery
8 Myhre, E., and Dale, J.: Hemolysis in Mitral Valvular Disease and Mitral Ball Valve Prostheses, Acta Med. Scand. 189: 547, 1971. 9 Magovern, G. J., Begg, F. 1., Kent, E. M., Cushing, W. B., Gerber, M. L., and Fisher, D. L.: The Experimental and Clinical Results of a Modified Cage Disc Mitral Prosthesis, J. THORAC. CARDIOVASC. SURG. 59: 109, 1970. 10 Sayed, H. M., Dacie, J. V., Hanaley, D. A., Lewis, S. M., and Cleland, W. P.: Hemolytic Anemia of Mechanical Origin After Open Heart Surgery, Thorax 16: 335, 1961. 11 Robinson, M. J., Hildner, F. J., and Greenberg, J. J.: Disc Variance of Beall Mitral Valve, Ann. Thorac. Surg. 11: 11, 1971. 12 Nichols, H. T., Fernandez, J., Morse, D., and Gooch, A. S.: Improved Results in 336 Patients With the Isolated Mitral Beall Valve Replacement, Chest 62: 266, 1972. 13 Vogel, J. H. K., Paton, B. C., Overy, H. R., Pappas, G., Davies, H., and Blount, S. G.:
Advantages of the Beall Valve Prosthesis, Chest 59: 249, 1971. 14 Ramsey, H. W., Williams, J. C., Jr., Vernon, C. R., Wheat, M. W., Daicoff, G. R., and Bartley, T. D.: Hemodynamic Findings Following Replacement of the Mitral Valve With the Beall Valve Prosthesis, J. THORAC. CARD10VASC. SURG. 62: 624, 1971. 15 Reid, J. A., Stevens, T. W., Sigwart, D., Fulweber, R. C., and Alexander, J. K.: Hemodynamic Evaluation of the Beall Mitral Valve Prosthesis, Circulation 45, 46: 1, 1972 (Supp\. I).
16 Linhart, J. W., Barold, S. S., Hildner, F. J., Samet, P., Piccinini, J. C., Marsten, J. L., and Greenberg, J. J.: Clinical and Hemodynamic Findings Following Replacement of the Mitral Valve With a Beall Valve Prosthesis (Dacron Velour-Covered Teflon-Disc Valve), Circulation 49, 50: 127, 1969 (Suppl. I). (For Discussion, see page 106)