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TRAUMATIC MITRAL INSUFFICIENCY FOLLOWING TRANSVENTRICULAR DILATATION FOR MITRAL STENOSIS
T R A U M A T I C MITRAL INSUFFICIENCY
FOLLOWING
TRANSVENTRICULAR D I L A T A T I O N FOR MITRAL STENOSIS V. O. Bjork, M.D., and E. Malers, M.D., Uppsala,
I
Sweden
valvotomy and traumatic mitral insufficiency are the main surgical factors responsible for poor late results in series of patients operated upon for mitral stenosis. Inadequate valvotomy also increases the incidence of restenosis,5- 14 which may be the real cause of late deterioration in many such cases. This seems to be true, as an increase of the effective mitral orifice to an area of only 1.5 to 2.0 sq. cm. should be sufficient to relieve the symptoms of mitral stenosis. In 1957, Logan 24 reported the use of transventricular dilatation under the guidance of the right index finger which was introduced into the left atrium in the usual way. Several reports have later proved that this method is superior to the transatrial approach 8 - 10 - 15 - 16 - 18 - 25 - 27 in restoring normal size to the mitral orifice; this has also been supported by hemodynamic measurements. 27 However, there are only a few reports of the incidence of traumatic mitral insufficiency when the transventricular method is employed. The aim of this paper is to report the follow-up results in 13 cases of traumatic mitral insuf ficiency. NADEQUATE
MATERIAL AND METHODS
Eighty-three patients were operated upon by the same surgeon at our clinic for " p u r e " mitral stenosis during the years 1958-1961. Transventricular com missurotomy was performed under controlled hypotension. The insufficiency was carefully evaluated by how far behind the mitral orifice the surgeon could palpate the regurgitant jet before and after commissurotomy. No patient had signs of insufficiency on palpation before valvotomy. In 12 of these 83 cases, there was some degree of mitral insufficiency after the valvotomy. Transven tricular dilatation of a concomitant aortic stenosis was also performed in 2 of these 12 cases. One third of the remaining 71 patients have been re-examined at our clinic. Only one of these patients had clinical signs of a slight mitral insufficiency. The remaining ones have been re-examined at hospitals near their homes. Thus, 13 cases of traumatic mitral insufficiency, 12 of which were noted at operation Prom the Departments of Thoracic Surgery (Head: V. O. BjBrk, M.D.) and Medicine (Head: B. Ask-Upmark, M.D.), University Hospital, Uppsala, Sweden. Received for publication Jan. 14, 1963. 84
TRAUMATIC
Vol. 46, N o . 1 July, 1963
MITRAL
INSUFFICIENCY
85
and the remaining case at re-examination, constitute the basis of this report. Seven of these 13 patients had pure mitral stenosis alone, 2 had a concomitant aortic stenosis, 3 had aortic insufficiency of slight to moderate degree, and the remaining one had a moderate systemic hypertension. In all cases there were typical clinical signs of mitral stenosis preoperatively. Eight heart catheterization was performed, as a rule, with determina tions of flow included (Fick method) before and after operation. Left heart catheterization was done in 6 patients and was combined with thoracic aortography and/or left ventricular angiocardiography. Re-examination has been per formed 1 to 3 years after operation. RESULTS
The surgical findings before and after valvotomy are listed in Table I. Calcification of the mitral valve was noted in 5 cases. In 8 cases the stenosis was very tight (not open to the tip of the index finger) and in 5 cases tight (open to the tip of the finger). No regurgitant jet could be palpated before commissurotomy, but could be in all cases except one afterwards, usually 1 to 2 cm. behind the mitral orifice. TABLE
CASE NO.
7 12 15 21 28 34 40 50 56 66 85 114 120
I.
CALCIFIED VALVE
SURGICAL FINDINGS AND R E S U L T S IN 13 CASES OF TRAUMATIC MITRAL INSUFFICIENCY
SIZE OF MITRAL ORIFICE BEFORE*
Very tight* Very tight Very tight
MITRAL I N S U F F I C I E N C Y ON PALPATION AFTER
4 cm. 2.5 cm. 3 cm.
FOLLOW-UP RESULTS
+ 1 cm. 3 cm.
Died a t operation Improved Not improved; open operation 0 Tightt 3 cm. 1 cm. Improved + Tight 3 cm. 1 cm. Improved + Died a t operation, + Very tight 2.5 cm. systemic embolism Not improved; 0 Very tight 4 cm. 1 cm. died 4 years later 4 cm. 1 cm. Not improved 0 Tight 0 3 cm. 1 cm. Improved Very tight + Tight 4 cm. 1 cm. Not improved 0 4 cm. 0 Improved Very tight 2 cm. Improved 0 Tight 3.5 cm. Systemic embolism + Very tight 3 cm. 1 to 2 cm. 2 months later; died •Very tight = the tip of the index finger could not pass through the orifice. tTight = the tip of the index finger could pass through the orifice. + 0 0
Two patients died at operation. The first one (Case 7) died from traumatic aortic and mitral insufficiency, but belonged to functional class IV and had an extremely high pulmonary vascular resistance. The second patient (Case 34) died within one day postoperatively from multiple systemic embolism. A third patient (Case 120) died suddenly 2 months postoperatively (embolism). The results at the re-examination of the 10 remaining patients are classified
BJORK A N D MALERS
86
TABLE I I . K N O W N DURATION OP NO.
AGE
SEX
7
46
F
30
12 15 21 28 34
48 36 48 46 45
F F F F M
23 11 18 1 8
40
42
F
50 56
32 49
66 85 114 120
J. Thoracic and Cardiovas. Surg.
CLINICAL DATA IN 13 PATIENTS W I T H TRAUMATIC
SYSTOLIC M U R M U R (AUSCULTATORY-GRADE: PHONOCARDIOGRAM") BEFORE
(YEARS)
1
AFTER
HEART R H Y T H M BEFORE
|
AFTER
-
AF
-
AF
%s
%8 4:PS 0 2:%S
s sS
AF S* 8 8 -
7
%s
4:PS
S
S
F F
1 14
0 0
3:PS 2:%S
s s
S 8
51
F
1
%s
3:P8
S"
S"
51 44 34
M F F
0 0 2
2:%8 0
Ejection type (stenotic)
0 0 0
10 6 6 mo.
AF
AF 8
AF S 8
Legend: S = sinus; A P = atrial fibrillation; x = with ventricular extrasystoles; xx = sinus brackets = pressure gradient over the aortic valve in millimeters of mercury. Systolic murmur: % S = early systolic murmur and only in the first half of systole; 2,3,4 :PS
TABLE I I I .
HEMODYNAMIC FINDINGS AT RIGHT HEART CATHETERIZATION IN 13 PATIENTS PA SYSTOLIC PRESSURE
BEFORE REST
1
BEFORE
WORK
WORK CASE NO.
PC M E A N PRESSURE
AFTER REST
1
| 2
AFTER WORK
WORK
1
REST
1
| 2
17 43 19 8 24
_ 34 27 44
15 10 9 8 -
35 15 20 —
35 26 —
34? 13
_ 22
34 9
33 25
42 -
12 30
39 8 _ 42
_ _ -
_ 25 15
_ , -
22 17 -
31 26 -
_ -
REST
28
107
12 15 21 28 34
26 68 35 25 44
52 58 42 92
33 25 27 19 —
60 34 34 —
40 50
51 20
71 24
56 66
78 52
134 50 _ -
38 68
138 36 _ 80
85 114 120
_ 44 38
_ 62 -
50 34 -
85 59 -
70 50
43
100
Legend: Work 1 = 150 or 200 kpm/min.; Work 2 = 300 or 400 kpm/min. (The same work load RV BD = end-diastolic pressure in the right ventricle.
Vol. 46. No. I July, 1963
TRAUMATIC
MITRAL
87
INSUFFICIENCY
MITRAL INSUFFICIENCY (BEFORE AND A F T E R OPERATION) PHYSICAL WORK CAPACITY (KPM/MIN.)
BEFORE 1
HEART VOLUME ( M L . PER M.2 BODY AREA)
AFTER
BEFORE
1
-
790
200 400 500 300 400
250 50 800 600
~
610 550 520 540 870
400
400
400
—
|
FUNCTIONAL GROUPING
AFTER
BEFORE
IV
-
540 520 440 440
~
III III II II III
II III I I
480
550
in
III
400 200
410 420
460 360
n in
II II
400
250
730
720
in
III
200 300 400
300 400
730 490 470
640 440
in in n
II II
with periods of atrial
flutter;
ASSOCIATED HEART DISEASE
AFTER
AS [40 mm.], A l postop. Myocardial disease Myocardial disease
— — —
—
AS = aortic stenosis;
AS [0 mm.], A I postop.
FOLLOW-UP RESULT
Died at operation Improved Not improved Improved Improved Died; systemic embolism Not improved
Not improved — Systemic hyperten Improved sion A I + myocardial dis-< Not improved ease Myocardial disease Improved Improved — Died 2 mo. later, cerebral em bolism AI
=
aortic
insufficiency.
The
figures
in
= grade (1-6) and pansystolic murmur.
W I T H TRAUMATIC MITRAL INSUFFICIENCY BEFORE OPERATION AND AT RE-EXAMINATION RE-EXAMINATION
CARDIAC INDEX BEFORE
RVBD
AFTER
WORK
1
WORK
1
BEFORE
AFTER
REST
3
-
2.4
—
—
-
0 7 3 5
5 7
2.4 2.1 3.7
-
2.3 2.8 2.7 1.8
-
2 2
-
3
3
—
-
1.8
4.3
-
3.4
REST
2.8 5.1 2.0
—
—
4.6
2.0 4.1
3.5 5.7
2.0
4 4
3 24
—
-—
-
1.3
4.1 3.0
-
10 8
-
"
2.2 2.6
2.8 4.1
"
"
8
"
2.1
ASSOCIATED HEART DISEASE
AS (40 mm.), A I postop. Myocardial disease Myocardial disease
— —
AFTER (YEARS)
Died at operation
4 3 2% 3
Improved Not improved Improved Improved Died at operation, systemic em bolism Not improved Not improved
—
2 2
—
3 l%-4
AS (0 mm.), A I postop. A I + myocardial dis ease Myocardial disease?
—
has been used pre- and postoperatively in each patient.)
RESULT
-
1% 1
"
Not improved Not improved; late death Improved Improved Late death; sys temic embolism
88
BJbRK AND MALEES
J. Thoracic and Cardiovas. Surg.
as improved in 6 cases and not improved in 4 cases, on the basis of clinical, hemodynamic, and, in some instances, angiocardiographic data. The clinical data before operation and at re-examination are summarized in Table II. Three of 6 improved patients had had an insignificant, apical, early-systolic murmur preoperatively of Grade 1-2 intensity as compared with 4 cases in this group postoperatively. In one patient (Case 85), this murmur is weakly transmitted to the left axilla postoperatively. All patients show higher physical working capacity and decreased heart size and can be placed in a better functional group.
Figs. 1A and IB.—The degree of mitral insufficiency is evaluated by left ventricular angio cardiography according to how far the contrast medium has reached into the aorta when the left atrium is completely filled with contrast. A, Case 85. The left atrium is not filled with contrast medium until the whole thoracic aorta is filled: Stage 5 = insignificant mitral insufficiency. B. Case 66. The left atrium is filled when the contrast medium has reached the aortic arch: Stage 3 = severe mitral insufficiency. (See Bjork and associates. 9 )
In Case 12, there is an irreversible atrial fibrillation with an increasing number of ventricular extrasystoles during the work test; and in Case 85 the heart volume is very large. The 4 patients (Cases 15, 40, 50, and 66), who are not improved, have all demonstrated an apical pansystolic murmur of the regurgitant type at re-examination. The heart size, the physical working capacity, and the functional class have not changed toward normal postoperatively. Case 15 exhibits frequent ventricular extrasystoles, especially during the work test, and Case 66 has recurrent episodes of atrial flutter.
Vol. 46, No. I July, 1963
TEAUMATIC MITRAL INSUFFICIENCY
89
°
Table I I I shows the hemodynamic findings before operation and at reexamination. The postoperative values of pressures and flows are significantly better in 4 of 6 improved patients. In Case 12 these values are unchanged. In Case 85, right heart catheterization was not performed before operation, but the postoperative values of pressures and flows are abnormal. In none of these cases are there clinical signs of re-stenosis. In 2 of the 4 unimproved cases, there were higher pressures and lower flow values at re-examination than before operation (Cases 40 and 66). However, the hemodynamic data are almost completely normal in 2 instances (Cases 15 and 50).
F i g . I S . — F o r legend
see opposite
page.
The hemodynamic findings at left heart catheterization and angiocardi ography before and/or after operation are listed in Table IV. This investiga tion was performed in 6 cases, one of which (Case 85) belonged to the improved group, all 4 unimproved cases, and Case 7 who died at operation. Case 85 has a normal end-diastolic left ventricular pressure, no pressure gradient over the aortic valve, a very slight degree of mitral insufficiency (Fig. 1.4.), and a slightto-moderate increase of the left ventricular end-diastolic volume.1 Three un-
B J 6 R K AND
90
MALERS
J. Thoracic and Cardiovas. Surg.
improved patients (Cases 15, 40, and 66) show, as abnormal findings, a mitral insufficiency of severe degree, according to our angiocardiographic evaluation (Fig. IB), and signs of aortic insufficiency-in Cases 15 and 66 of slight degree and in Case 40 of severe degree.31 One of these patients (Case 66) died 4 years after operation ( 2 ^ years after the first re-examination). The findings at autopsy were thickened, rigid mitral cusps but no significant stenosis, slightly fibrotic aortic cusps, and a fibrotic myocardium. The last unimproved patient (Case 40) shows normal pressure values at left heart catheterization. She has a slight-to-moderate mitral insufficiency and is in good condition. TABLE IV. HEMODYNAMIC FINDINGS AT L E F T HEART CATHETERIZATION I N 6 P A T I E N T S TRAUMATIC MITRAL INSUFFICIENCY BEFORE OPERATION AND AT RE-EXAMINATION ( P R E S S U R E S IN MM. Hg)* LiT-PREKSURE CASE NO.
7
BEFORE
AFTER
B
ED
S
164
0
15
| ED
-
-
LV-ANGIOG-
THORACIC
( MI-STAGE)
(AI-STAGE)
BEFORE
AFTER
BEFORE
AFTER
0
-
-
-
140 10
3
1
—
RE-EX AMINATION RESULTS
Died at operation Not im proved
AFTER (YEARS)
WITH
COMMENTS
3
Open op eration, 1962
Not im 2 — proved — — Not im 50 110 5 0 2 ~ — proved — — Not im Dead after 66 160 10 3 2 2 iy* proved 4 yr. 85 5 0 Improved 1% - - 116 12 — Legend: LV = left ventricle; S = systolic; ED = end-diastolic. •The degree of mitral insufficiency at left ventricular angiocardiography is evaluated as described by BJ8rk,» the degree of aortic insufficiency a t thoracic aortography as described by Runco and co-workers. 31 40
140 10
92
5
0
3
4
- ■
A significant degree of myocardial dysfunction is considered to be present in 2 patients (Cases 12 and 85) who belonged to the improved group and in 2 additional ones (Nos. 15 and 40) who belonged to the unimproved group, be cause of arrythmias (especially ventricular extrasystoles which increased in number during work test) and/or greatly enlarged heart and/or some hemo dynamic and angiocardiographic findings (increased ventricular end-diastolic pressure and increased left ventricular end-diastolic and end-systolic volume). DISCUSSION
There are varying figures reported about the incidence of traumatic mitral insufficiency. This mainly depends on different nomenclature and different diag nostic criteria. Traumatic mitral insufficiency is defined by us as a regurgitation created at commissurotomy in patients without previous signs of regurgitation, either clinically or by palpation before valvotomy. The diagnostic criteria used by us are a reflux noted after commissurotomy, as well as follow-up results. The re-examination includes a careful clinical assessment, hemodynamic and, in selected cases, angiocardiographic studies.
Vol. 46, No. 1 TRAUMATIC MITRAL INSUFFICIENCY 91 July, 1963 ^ I n the t r a n s a t r i a l series t h e incidence of t r a u m a t i c m i t r a l insufficiency of significant to severe degree seems to v a r y from 1 to 6 p e r cent, 3 - 4 * 6 ' 12 ' "• 1 7 ' 1 9 ' 22,28-30,34 t h e o v e i v a n_ incidence from 10 to 37 per cent.2-3-7- "• "• 2 3 The figures reported by Baden 2 may be mentioned as representative: reflux after commissurotomy in 16 per cent (14 of 91 patients) and at re-examination in 11 of all patients there was a significant mitral insufficiency in 5 per cent (5 cases). Coelho" reported similar figures, 13 and 5 per cent, respectively. In a transventricular series, Logan 25 noted traumatic mitral insufficiency on palpation at operation in 19 per cent as compared with 16 per cent in a series of patients having had digital commissurotomy. However, patients in whom a previously existing mitral insufficiency seemed to be increased by operation were included in these figures. Belcher 8 noted a mitral insufficiency produced or worsened in 20 of 42 cases after operation for re-stenosis. There are only a few further reports mentioning the incidence in small series as about 0 to 5 per cent.18- " In a recently published series, Logan26 noted traumatic mitral insuf ficiency in only 8 per cent. In our series, traumatic mitral insufficiency occurred in 16 per cent (13 cases of 83). In 2 cases, this complication was a contributory factor to the death of the patient, in one instance on the operating table and in the second case later. Two additional patients died, both from systemic embolism, one at operation and the second, later. In none of these cases was the traumatic mitral insufficiency judged to be significant. At re-examination of the 9 remaining patients, traumatic mitral insufficiency was significant in only 2 cases; in one case it necessitated re-operation by an open method.33 In one additional un improved patient there was also a severe degree of traumatic aortic insufficiency as the main cause of the lack of improvement. All 6 remaining patients were improved and in only one of these were there clinical signs of a slight mitral insufficiency, which was verified by left ventricular angiocardiography. Thus, traumatic mitral insufficiency was of significance in only 4 patients in our series (5 per cent), in 2 of whom it was fatal but in these 2 cases this complication was only a contributory factor in the death of the patient. We consider this incidence of complication to be acceptable and transventricular commissurotomy to be the method of choice in cases of pure mitral stenosis. In
TABLE V. THE SIZE OF THE MITRAL ORIFICE OBTAINED AFTER COMMISSUROTOMY COMPARING THE DIGITAL
(60
CASES)
W I T H THE TRANSVENTRICULAR
SIZE OF MITRAL ORIFICE AFTER OPERATION
DILATATION
DIGITAL COMMISSUROTOMY (NO. CASES)
(83
CASES)
TECHNIQUE*
TRANSVENTRICULAR DILATATION (NO. CASES)
4 cm. (2 fingerbreadths) 7 37 3.5 cm. ( 1 % fingerbreadths) 6 13 3 cm. (\% fingerbreadths) 30 29 2.5 cm. (11,4 fingerbreadths) 14 4 2 cm. (1 fingerbreadth) 3 0 Totals 60 83 •The size of the mitral orifice was evaluated by the index finger of the same surgeon and the greatest diameter was calculated in- centimeters in which 1 fingerbreadth corresponds to 2 cm.
B J 6 E K AND MALERS
92
J. Thoracic and Cardiovas. Surg.
support of this opinion the surgical results in our transventricular series is far better than in our transatrial series (see Table V ) . Thus, a satisfactory local result was obtained in the majority of the patients treated with transventricular dilatation. It may be true that a better result can be achieved by the use of an openheart operation in cases of pure mitral stenosis20 than by transatrial digital valvotcmy, but only at the cost of a significantly higher mortality rate. 1 1 ' 3 1 However, at open-heart operation, surgeons used to transventricular dilatation will find themselves unable to do more to the valve than by using the dilator. As transventricular dilatation affords a satisfactory surgical result associated with a low mortality rate, we consider this method to be superior to both the transatrial and the open-heart operation for pure mitral stenosis. Only in pa tients with a heavily calcified and immobile anterior cusp can a total valve replacement give a better result. SUMMARY
In a series of 83 cases of " p u r e " mitral stenosis, sometimes associated with aortic valvular disease of slight-to-moderate degree, there were 13 cases of traumatic mitral insufficiency. Traumatic mitral insufficiency was of significance in only 4 patients (5 per cent) with fatal outcome in 2. I n neither of these 2 cases was this complication the only or the dominating factor in the death of the patient. We consider that transventricular commissurotomy is the method of choice in cases of pure mitral stenosis. REFERENCES 1. Arvidsson, H . : Angiocardiographic Determination of Left Ventricular Volume, Acta radiol. 56: 321, 1961. 2. Baden, H . : Surgical Treatment of Mitral Stenosis, Store Nordiske Videnskabsboghandel, Copenhagen, 1958. , 3. Bailey, C. P . : Surgery of the Heart, Philadelphia, 1955, Lea & Febiger. 4. Bailey, C. P., Jamison, W. L., Bakst, A. E., Bolton, H. E., Nichols, H . T., and Gemeinhardt, W . : The,. Surgical Coorrection of Mitral Insufficiency by the Use of Pericardial Grafts, J . THORACIC SURG. 28: 551, 1954.
5. Bailey, C , Goldberg, H., and Morse, D. P . : Recurrent Mitral Stenosis: Diagnosis by Catheteriza%n of the Left Side of the Heart, J . A. M. A. 163: 1576, 1957. 6. Baker, C , Brock, R., and Campbell, M.: Mitral Valvotomy: A Follow-up of 45 Pa tients for Three Years and Over, Brit. M. J . 2 : 983, 1955. 7. Belcher, J . R.: The Influence of Mitral Regurgitation on the Results of Mitral Valvotomy, Lancet 2 : 7, 1956. 8. Belcher, J . R.: Restenosis of the Mitral Valve, Lancet 1: 181, 1960. 9. Bjork, V. O., Lodin, H., and Malers, E . : The Evaluation of the Degree of Mitral In sufficiency by Selective Left Ventricular Angiocardiography, Am. Heart J . 60: 601, 1960. 10. Bjork, V. O., H:son Holmdahl, M., and Lof, B . : Transventricular Mitral Valvulotomy Under Controlled Hypotension, J . THORACIC SURG. 4 1 : 236, 1961. 11. Bjork, V. O., and Malers, E . : Closed Versus Open Operation in Mitral Stenosis Com bined With Mitral Insufficiency. (To be published.) 12. Bolton, H., and Musser, B. G.: Cardiac Surgery for Acquired Valvular Disease: Modi fications Experienced With 2,000 Cases, Dis. Chest. 32: 247, 1957. 13. Brest, A. N., Uricchio, J . P., and Likoff, W . : Traumatic Mitral Insufficiency: A Com plication of Mitral Commissurotomy, J . A. M. A. 175: 1081, 1961. 14. Coelho, E., e Sa, A. B., Maltez, J., de Paria, E., Amram, S. S., Luiz, A. S., Coelho, E. M., and Tavares, V . : Postoperative Physiopathologic Results "in Mitral Stenosis, Am. J . Cardiol. 4 : 163, 1959.
Vol. 46. No. 1
TRAUMATIC
MITRAL
July, 1963
INSUFFICIENCY
93 "
15. Cooley, D. A., and Stoneburner, J . M.: Transventricular Mitral Valvotomy, Surgery 46: 414, 1959. 16. Crum, H. B., and Tsapogas, M. J . C.: Transventricular Mitral Valvotomy: Report of 50 Consecutive Cases, Lancet 2: 880, 1959. 17. Edwards, W. S., Lyons, C , Thomas, H. D., and Clark, L. C : Management of Traumatic Mitral Insufficiency, Ann. Surg. 153: 822, 1961. 18. Gerbode, F . : Transventricular Mitral Valvotomy, Circulation 2 1 : 563, 1960. 19. Harken, D. E., Black, H., Taylor, W. J., Thrower, W. B., and Ellis, L. B . : Reoperation for Mitral Stenosis, Circulation 23: 7, 1961. 20. Kay, E. B., and Zimmermann, H. A.: Surgical Treatment of Mitral Stenosis: Open Versus Closed Technics, Am. J . Cardiol. 10: 1, 1962. 21. Kezdi, P., and Wessel, H. U.: Mitral Commissurotomy: Comparison of Clinical and Hemodynamic Results One to Three Years After Surgery, Am. J . Cardiol. 3 : 45, 1959. 22. Lenegre, J., and Coblenz, B . : L a commissurotomie mitrale, Arch. mal. coeur 46: 577, 1953. 23. Likoff, W., and Uricchio, J . F . : Results of Mitral Commissurotomy, J . A. M. A. 166: 737, 1958. 24. Logan, A.: The Transventricular Route for Mitral Valvulotomy, Kardiologia Polska 1: 49, 1957. 25. Logan, A., and Turner, R.: Surgical Treatment of Mitral Stenosis, Lancet 2: 874, 1959. 26. Logan, A., Lowther, C. P., and Turner, R. W. D.: Reoperation for Mitral Stenosis, Lancet 1: 443, 1962. 27. Morrow, A. G., and Braunwald, N . S.: Transventricular Mitral Commissurotomy, J . THORACIC SURG. 4 1 :
225,
1961.
28. Mounsey, P . : Determination of Success After Mitral Valvotomy, Brit. M. J . 2: 311, 1957. 29. Pe>ez-Alvarez, J . J . : Experience With the Beck Finger-Dilator in Mitral Valvulotomy, J . THORACIC SURG. 38: 186,
1959.
30. Ross, J . K . : Failed Mitral Valvotomy, Thorax 14: 320, 1959. 31. Runco, V., Molnar, W., Meokstroth, C. V., and Ryan, J . M.: The Graham-Steell Murmur Versus Aortic Regurgitation in Rheumatic Heart Disease: Results of Aortic Valvulography, Am. J . Med. 3 1 : 71, 1961. 32. Scannell, J . G., Burke, J . F., Saidi, F., and Turner, J . D . : Five-Year Follow-up Study of Closed Mitral Valvulotomy, J . THORACIC SURG. 40: 723, 1960. 33. Starr, A., and Edwards, M. L.: Mitral Replacement: Clinical Experience With a BallValve Prosthesis, Ann. Surg. 154: 726, 1961. 34. Turner, R. W. D., and Fraser, H. R. L.: Mitral Valvotomy, Lancet 2: 525 and 587, 1956.
FOLLOWING
TRANSVENTRICULAR D I L A T A T I O N FOR MITRAL STENOSIS V. O. Bjork, M.D., and E. Malers, M.D., Uppsala,
I
Sweden
valvotomy and traumatic mitral insufficiency are the main surgical factors responsible for poor late results in series of patients operated upon for mitral stenosis. Inadequate valvotomy also increases the incidence of restenosis,5- 14 which may be the real cause of late deterioration in many such cases. This seems to be true, as an increase of the effective mitral orifice to an area of only 1.5 to 2.0 sq. cm. should be sufficient to relieve the symptoms of mitral stenosis. In 1957, Logan 24 reported the use of transventricular dilatation under the guidance of the right index finger which was introduced into the left atrium in the usual way. Several reports have later proved that this method is superior to the transatrial approach 8 - 10 - 15 - 16 - 18 - 25 - 27 in restoring normal size to the mitral orifice; this has also been supported by hemodynamic measurements. 27 However, there are only a few reports of the incidence of traumatic mitral insufficiency when the transventricular method is employed. The aim of this paper is to report the follow-up results in 13 cases of traumatic mitral insuf ficiency. NADEQUATE
MATERIAL AND METHODS
Eighty-three patients were operated upon by the same surgeon at our clinic for " p u r e " mitral stenosis during the years 1958-1961. Transventricular com missurotomy was performed under controlled hypotension. The insufficiency was carefully evaluated by how far behind the mitral orifice the surgeon could palpate the regurgitant jet before and after commissurotomy. No patient had signs of insufficiency on palpation before valvotomy. In 12 of these 83 cases, there was some degree of mitral insufficiency after the valvotomy. Transven tricular dilatation of a concomitant aortic stenosis was also performed in 2 of these 12 cases. One third of the remaining 71 patients have been re-examined at our clinic. Only one of these patients had clinical signs of a slight mitral insufficiency. The remaining ones have been re-examined at hospitals near their homes. Thus, 13 cases of traumatic mitral insufficiency, 12 of which were noted at operation Prom the Departments of Thoracic Surgery (Head: V. O. BjBrk, M.D.) and Medicine (Head: B. Ask-Upmark, M.D.), University Hospital, Uppsala, Sweden. Received for publication Jan. 14, 1963. 84
TRAUMATIC
Vol. 46, N o . 1 July, 1963
MITRAL
INSUFFICIENCY
85
and the remaining case at re-examination, constitute the basis of this report. Seven of these 13 patients had pure mitral stenosis alone, 2 had a concomitant aortic stenosis, 3 had aortic insufficiency of slight to moderate degree, and the remaining one had a moderate systemic hypertension. In all cases there were typical clinical signs of mitral stenosis preoperatively. Eight heart catheterization was performed, as a rule, with determina tions of flow included (Fick method) before and after operation. Left heart catheterization was done in 6 patients and was combined with thoracic aortography and/or left ventricular angiocardiography. Re-examination has been per formed 1 to 3 years after operation. RESULTS
The surgical findings before and after valvotomy are listed in Table I. Calcification of the mitral valve was noted in 5 cases. In 8 cases the stenosis was very tight (not open to the tip of the index finger) and in 5 cases tight (open to the tip of the finger). No regurgitant jet could be palpated before commissurotomy, but could be in all cases except one afterwards, usually 1 to 2 cm. behind the mitral orifice. TABLE
CASE NO.
7 12 15 21 28 34 40 50 56 66 85 114 120
I.
CALCIFIED VALVE
SURGICAL FINDINGS AND R E S U L T S IN 13 CASES OF TRAUMATIC MITRAL INSUFFICIENCY
SIZE OF MITRAL ORIFICE BEFORE*
Very tight* Very tight Very tight
MITRAL I N S U F F I C I E N C Y ON PALPATION AFTER
4 cm. 2.5 cm. 3 cm.
FOLLOW-UP RESULTS
+ 1 cm. 3 cm.
Died a t operation Improved Not improved; open operation 0 Tightt 3 cm. 1 cm. Improved + Tight 3 cm. 1 cm. Improved + Died a t operation, + Very tight 2.5 cm. systemic embolism Not improved; 0 Very tight 4 cm. 1 cm. died 4 years later 4 cm. 1 cm. Not improved 0 Tight 0 3 cm. 1 cm. Improved Very tight + Tight 4 cm. 1 cm. Not improved 0 4 cm. 0 Improved Very tight 2 cm. Improved 0 Tight 3.5 cm. Systemic embolism + Very tight 3 cm. 1 to 2 cm. 2 months later; died •Very tight = the tip of the index finger could not pass through the orifice. tTight = the tip of the index finger could pass through the orifice. + 0 0
Two patients died at operation. The first one (Case 7) died from traumatic aortic and mitral insufficiency, but belonged to functional class IV and had an extremely high pulmonary vascular resistance. The second patient (Case 34) died within one day postoperatively from multiple systemic embolism. A third patient (Case 120) died suddenly 2 months postoperatively (embolism). The results at the re-examination of the 10 remaining patients are classified
BJORK A N D MALERS
86
TABLE I I . K N O W N DURATION OP NO.
AGE
SEX
7
46
F
30
12 15 21 28 34
48 36 48 46 45
F F F F M
23 11 18 1 8
40
42
F
50 56
32 49
66 85 114 120
J. Thoracic and Cardiovas. Surg.
CLINICAL DATA IN 13 PATIENTS W I T H TRAUMATIC
SYSTOLIC M U R M U R (AUSCULTATORY-GRADE: PHONOCARDIOGRAM") BEFORE
(YEARS)
1
AFTER
HEART R H Y T H M BEFORE
|
AFTER
-
AF
-
AF
%s
%8 4:PS 0 2:%S
s sS
AF S* 8 8 -
7
%s
4:PS
S
S
F F
1 14
0 0
3:PS 2:%S
s s
S 8
51
F
1
%s
3:P8
S"
S"
51 44 34
M F F
0 0 2
2:%8 0
Ejection type (stenotic)
0 0 0
10 6 6 mo.
AF
AF 8
AF S 8
Legend: S = sinus; A P = atrial fibrillation; x = with ventricular extrasystoles; xx = sinus brackets = pressure gradient over the aortic valve in millimeters of mercury. Systolic murmur: % S = early systolic murmur and only in the first half of systole; 2,3,4 :PS
TABLE I I I .
HEMODYNAMIC FINDINGS AT RIGHT HEART CATHETERIZATION IN 13 PATIENTS PA SYSTOLIC PRESSURE
BEFORE REST
1
BEFORE
WORK
WORK CASE NO.
PC M E A N PRESSURE
AFTER REST
1
| 2
AFTER WORK
WORK
1
REST
1
| 2
17 43 19 8 24
_ 34 27 44
15 10 9 8 -
35 15 20 —
35 26 —
34? 13
_ 22
34 9
33 25
42 -
12 30
39 8 _ 42
_ _ -
_ 25 15
_ , -
22 17 -
31 26 -
_ -
REST
28
107
12 15 21 28 34
26 68 35 25 44
52 58 42 92
33 25 27 19 —
60 34 34 —
40 50
51 20
71 24
56 66
78 52
134 50 _ -
38 68
138 36 _ 80
85 114 120
_ 44 38
_ 62 -
50 34 -
85 59 -
70 50
43
100
Legend: Work 1 = 150 or 200 kpm/min.; Work 2 = 300 or 400 kpm/min. (The same work load RV BD = end-diastolic pressure in the right ventricle.
Vol. 46. No. I July, 1963
TRAUMATIC
MITRAL
87
INSUFFICIENCY
MITRAL INSUFFICIENCY (BEFORE AND A F T E R OPERATION) PHYSICAL WORK CAPACITY (KPM/MIN.)
BEFORE 1
HEART VOLUME ( M L . PER M.2 BODY AREA)
AFTER
BEFORE
1
-
790
200 400 500 300 400
250 50 800 600
~
610 550 520 540 870
400
400
400
—
|
FUNCTIONAL GROUPING
AFTER
BEFORE
IV
-
540 520 440 440
~
III III II II III
II III I I
480
550
in
III
400 200
410 420
460 360
n in
II II
400
250
730
720
in
III
200 300 400
300 400
730 490 470
640 440
in in n
II II
with periods of atrial
flutter;
ASSOCIATED HEART DISEASE
AFTER
AS [40 mm.], A l postop. Myocardial disease Myocardial disease
— — —
—
AS = aortic stenosis;
AS [0 mm.], A I postop.
FOLLOW-UP RESULT
Died at operation Improved Not improved Improved Improved Died; systemic embolism Not improved
Not improved — Systemic hyperten Improved sion A I + myocardial dis-< Not improved ease Myocardial disease Improved Improved — Died 2 mo. later, cerebral em bolism AI
=
aortic
insufficiency.
The
figures
in
= grade (1-6) and pansystolic murmur.
W I T H TRAUMATIC MITRAL INSUFFICIENCY BEFORE OPERATION AND AT RE-EXAMINATION RE-EXAMINATION
CARDIAC INDEX BEFORE
RVBD
AFTER
WORK
1
WORK
1
BEFORE
AFTER
REST
3
-
2.4
—
—
-
0 7 3 5
5 7
2.4 2.1 3.7
-
2.3 2.8 2.7 1.8
-
2 2
-
3
3
—
-
1.8
4.3
-
3.4
REST
2.8 5.1 2.0
—
—
4.6
2.0 4.1
3.5 5.7
2.0
4 4
3 24
—
-—
-
1.3
4.1 3.0
-
10 8
-
"
2.2 2.6
2.8 4.1
"
"
8
"
2.1
ASSOCIATED HEART DISEASE
AS (40 mm.), A I postop. Myocardial disease Myocardial disease
— —
AFTER (YEARS)
Died at operation
4 3 2% 3
Improved Not improved Improved Improved Died at operation, systemic em bolism Not improved Not improved
—
2 2
—
3 l%-4
AS (0 mm.), A I postop. A I + myocardial dis ease Myocardial disease?
—
has been used pre- and postoperatively in each patient.)
RESULT
-
1% 1
"
Not improved Not improved; late death Improved Improved Late death; sys temic embolism
88
BJbRK AND MALEES
J. Thoracic and Cardiovas. Surg.
as improved in 6 cases and not improved in 4 cases, on the basis of clinical, hemodynamic, and, in some instances, angiocardiographic data. The clinical data before operation and at re-examination are summarized in Table II. Three of 6 improved patients had had an insignificant, apical, early-systolic murmur preoperatively of Grade 1-2 intensity as compared with 4 cases in this group postoperatively. In one patient (Case 85), this murmur is weakly transmitted to the left axilla postoperatively. All patients show higher physical working capacity and decreased heart size and can be placed in a better functional group.
Figs. 1A and IB.—The degree of mitral insufficiency is evaluated by left ventricular angio cardiography according to how far the contrast medium has reached into the aorta when the left atrium is completely filled with contrast. A, Case 85. The left atrium is not filled with contrast medium until the whole thoracic aorta is filled: Stage 5 = insignificant mitral insufficiency. B. Case 66. The left atrium is filled when the contrast medium has reached the aortic arch: Stage 3 = severe mitral insufficiency. (See Bjork and associates. 9 )
In Case 12, there is an irreversible atrial fibrillation with an increasing number of ventricular extrasystoles during the work test; and in Case 85 the heart volume is very large. The 4 patients (Cases 15, 40, 50, and 66), who are not improved, have all demonstrated an apical pansystolic murmur of the regurgitant type at re-examination. The heart size, the physical working capacity, and the functional class have not changed toward normal postoperatively. Case 15 exhibits frequent ventricular extrasystoles, especially during the work test, and Case 66 has recurrent episodes of atrial flutter.
Vol. 46, No. I July, 1963
TEAUMATIC MITRAL INSUFFICIENCY
89
°
Table I I I shows the hemodynamic findings before operation and at reexamination. The postoperative values of pressures and flows are significantly better in 4 of 6 improved patients. In Case 12 these values are unchanged. In Case 85, right heart catheterization was not performed before operation, but the postoperative values of pressures and flows are abnormal. In none of these cases are there clinical signs of re-stenosis. In 2 of the 4 unimproved cases, there were higher pressures and lower flow values at re-examination than before operation (Cases 40 and 66). However, the hemodynamic data are almost completely normal in 2 instances (Cases 15 and 50).
F i g . I S . — F o r legend
see opposite
page.
The hemodynamic findings at left heart catheterization and angiocardi ography before and/or after operation are listed in Table IV. This investiga tion was performed in 6 cases, one of which (Case 85) belonged to the improved group, all 4 unimproved cases, and Case 7 who died at operation. Case 85 has a normal end-diastolic left ventricular pressure, no pressure gradient over the aortic valve, a very slight degree of mitral insufficiency (Fig. 1.4.), and a slightto-moderate increase of the left ventricular end-diastolic volume.1 Three un-
B J 6 R K AND
90
MALERS
J. Thoracic and Cardiovas. Surg.
improved patients (Cases 15, 40, and 66) show, as abnormal findings, a mitral insufficiency of severe degree, according to our angiocardiographic evaluation (Fig. IB), and signs of aortic insufficiency-in Cases 15 and 66 of slight degree and in Case 40 of severe degree.31 One of these patients (Case 66) died 4 years after operation ( 2 ^ years after the first re-examination). The findings at autopsy were thickened, rigid mitral cusps but no significant stenosis, slightly fibrotic aortic cusps, and a fibrotic myocardium. The last unimproved patient (Case 40) shows normal pressure values at left heart catheterization. She has a slight-to-moderate mitral insufficiency and is in good condition. TABLE IV. HEMODYNAMIC FINDINGS AT L E F T HEART CATHETERIZATION I N 6 P A T I E N T S TRAUMATIC MITRAL INSUFFICIENCY BEFORE OPERATION AND AT RE-EXAMINATION ( P R E S S U R E S IN MM. Hg)* LiT-PREKSURE CASE NO.
7
BEFORE
AFTER
B
ED
S
164
0
15
| ED
-
-
LV-ANGIOG-
THORACIC
( MI-STAGE)
(AI-STAGE)
BEFORE
AFTER
BEFORE
AFTER
0
-
-
-
140 10
3
1
—
RE-EX AMINATION RESULTS
Died at operation Not im proved
AFTER (YEARS)
WITH
COMMENTS
3
Open op eration, 1962
Not im 2 — proved — — Not im 50 110 5 0 2 ~ — proved — — Not im Dead after 66 160 10 3 2 2 iy* proved 4 yr. 85 5 0 Improved 1% - - 116 12 — Legend: LV = left ventricle; S = systolic; ED = end-diastolic. •The degree of mitral insufficiency at left ventricular angiocardiography is evaluated as described by BJ8rk,» the degree of aortic insufficiency a t thoracic aortography as described by Runco and co-workers. 31 40
140 10
92
5
0
3
4
- ■
A significant degree of myocardial dysfunction is considered to be present in 2 patients (Cases 12 and 85) who belonged to the improved group and in 2 additional ones (Nos. 15 and 40) who belonged to the unimproved group, be cause of arrythmias (especially ventricular extrasystoles which increased in number during work test) and/or greatly enlarged heart and/or some hemo dynamic and angiocardiographic findings (increased ventricular end-diastolic pressure and increased left ventricular end-diastolic and end-systolic volume). DISCUSSION
There are varying figures reported about the incidence of traumatic mitral insufficiency. This mainly depends on different nomenclature and different diag nostic criteria. Traumatic mitral insufficiency is defined by us as a regurgitation created at commissurotomy in patients without previous signs of regurgitation, either clinically or by palpation before valvotomy. The diagnostic criteria used by us are a reflux noted after commissurotomy, as well as follow-up results. The re-examination includes a careful clinical assessment, hemodynamic and, in selected cases, angiocardiographic studies.
Vol. 46, No. 1 TRAUMATIC MITRAL INSUFFICIENCY 91 July, 1963 ^ I n the t r a n s a t r i a l series t h e incidence of t r a u m a t i c m i t r a l insufficiency of significant to severe degree seems to v a r y from 1 to 6 p e r cent, 3 - 4 * 6 ' 12 ' "• 1 7 ' 1 9 ' 22,28-30,34 t h e o v e i v a n_ incidence from 10 to 37 per cent.2-3-7- "• "• 2 3 The figures reported by Baden 2 may be mentioned as representative: reflux after commissurotomy in 16 per cent (14 of 91 patients) and at re-examination in 11 of all patients there was a significant mitral insufficiency in 5 per cent (5 cases). Coelho" reported similar figures, 13 and 5 per cent, respectively. In a transventricular series, Logan 25 noted traumatic mitral insufficiency on palpation at operation in 19 per cent as compared with 16 per cent in a series of patients having had digital commissurotomy. However, patients in whom a previously existing mitral insufficiency seemed to be increased by operation were included in these figures. Belcher 8 noted a mitral insufficiency produced or worsened in 20 of 42 cases after operation for re-stenosis. There are only a few further reports mentioning the incidence in small series as about 0 to 5 per cent.18- " In a recently published series, Logan26 noted traumatic mitral insuf ficiency in only 8 per cent. In our series, traumatic mitral insufficiency occurred in 16 per cent (13 cases of 83). In 2 cases, this complication was a contributory factor to the death of the patient, in one instance on the operating table and in the second case later. Two additional patients died, both from systemic embolism, one at operation and the second, later. In none of these cases was the traumatic mitral insufficiency judged to be significant. At re-examination of the 9 remaining patients, traumatic mitral insufficiency was significant in only 2 cases; in one case it necessitated re-operation by an open method.33 In one additional un improved patient there was also a severe degree of traumatic aortic insufficiency as the main cause of the lack of improvement. All 6 remaining patients were improved and in only one of these were there clinical signs of a slight mitral insufficiency, which was verified by left ventricular angiocardiography. Thus, traumatic mitral insufficiency was of significance in only 4 patients in our series (5 per cent), in 2 of whom it was fatal but in these 2 cases this complication was only a contributory factor in the death of the patient. We consider this incidence of complication to be acceptable and transventricular commissurotomy to be the method of choice in cases of pure mitral stenosis. In
TABLE V. THE SIZE OF THE MITRAL ORIFICE OBTAINED AFTER COMMISSUROTOMY COMPARING THE DIGITAL
(60
CASES)
W I T H THE TRANSVENTRICULAR
SIZE OF MITRAL ORIFICE AFTER OPERATION
DILATATION
DIGITAL COMMISSUROTOMY (NO. CASES)
(83
CASES)
TECHNIQUE*
TRANSVENTRICULAR DILATATION (NO. CASES)
4 cm. (2 fingerbreadths) 7 37 3.5 cm. ( 1 % fingerbreadths) 6 13 3 cm. (\% fingerbreadths) 30 29 2.5 cm. (11,4 fingerbreadths) 14 4 2 cm. (1 fingerbreadth) 3 0 Totals 60 83 •The size of the mitral orifice was evaluated by the index finger of the same surgeon and the greatest diameter was calculated in- centimeters in which 1 fingerbreadth corresponds to 2 cm.
B J 6 E K AND MALERS
92
J. Thoracic and Cardiovas. Surg.
support of this opinion the surgical results in our transventricular series is far better than in our transatrial series (see Table V ) . Thus, a satisfactory local result was obtained in the majority of the patients treated with transventricular dilatation. It may be true that a better result can be achieved by the use of an openheart operation in cases of pure mitral stenosis20 than by transatrial digital valvotcmy, but only at the cost of a significantly higher mortality rate. 1 1 ' 3 1 However, at open-heart operation, surgeons used to transventricular dilatation will find themselves unable to do more to the valve than by using the dilator. As transventricular dilatation affords a satisfactory surgical result associated with a low mortality rate, we consider this method to be superior to both the transatrial and the open-heart operation for pure mitral stenosis. Only in pa tients with a heavily calcified and immobile anterior cusp can a total valve replacement give a better result. SUMMARY
In a series of 83 cases of " p u r e " mitral stenosis, sometimes associated with aortic valvular disease of slight-to-moderate degree, there were 13 cases of traumatic mitral insufficiency. Traumatic mitral insufficiency was of significance in only 4 patients (5 per cent) with fatal outcome in 2. I n neither of these 2 cases was this complication the only or the dominating factor in the death of the patient. We consider that transventricular commissurotomy is the method of choice in cases of pure mitral stenosis. REFERENCES 1. Arvidsson, H . : Angiocardiographic Determination of Left Ventricular Volume, Acta radiol. 56: 321, 1961. 2. Baden, H . : Surgical Treatment of Mitral Stenosis, Store Nordiske Videnskabsboghandel, Copenhagen, 1958. , 3. Bailey, C. P . : Surgery of the Heart, Philadelphia, 1955, Lea & Febiger. 4. Bailey, C. P., Jamison, W. L., Bakst, A. E., Bolton, H. E., Nichols, H . T., and Gemeinhardt, W . : The,. Surgical Coorrection of Mitral Insufficiency by the Use of Pericardial Grafts, J . THORACIC SURG. 28: 551, 1954.
5. Bailey, C , Goldberg, H., and Morse, D. P . : Recurrent Mitral Stenosis: Diagnosis by Catheteriza%n of the Left Side of the Heart, J . A. M. A. 163: 1576, 1957. 6. Baker, C , Brock, R., and Campbell, M.: Mitral Valvotomy: A Follow-up of 45 Pa tients for Three Years and Over, Brit. M. J . 2 : 983, 1955. 7. Belcher, J . R.: The Influence of Mitral Regurgitation on the Results of Mitral Valvotomy, Lancet 2 : 7, 1956. 8. Belcher, J . R.: Restenosis of the Mitral Valve, Lancet 1: 181, 1960. 9. Bjork, V. O., Lodin, H., and Malers, E . : The Evaluation of the Degree of Mitral In sufficiency by Selective Left Ventricular Angiocardiography, Am. Heart J . 60: 601, 1960. 10. Bjork, V. O., H:son Holmdahl, M., and Lof, B . : Transventricular Mitral Valvulotomy Under Controlled Hypotension, J . THORACIC SURG. 4 1 : 236, 1961. 11. Bjork, V. O., and Malers, E . : Closed Versus Open Operation in Mitral Stenosis Com bined With Mitral Insufficiency. (To be published.) 12. Bolton, H., and Musser, B. G.: Cardiac Surgery for Acquired Valvular Disease: Modi fications Experienced With 2,000 Cases, Dis. Chest. 32: 247, 1957. 13. Brest, A. N., Uricchio, J . P., and Likoff, W . : Traumatic Mitral Insufficiency: A Com plication of Mitral Commissurotomy, J . A. M. A. 175: 1081, 1961. 14. Coelho, E., e Sa, A. B., Maltez, J., de Paria, E., Amram, S. S., Luiz, A. S., Coelho, E. M., and Tavares, V . : Postoperative Physiopathologic Results "in Mitral Stenosis, Am. J . Cardiol. 4 : 163, 1959.
Vol. 46. No. 1
TRAUMATIC
MITRAL
July, 1963
INSUFFICIENCY
93 "
15. Cooley, D. A., and Stoneburner, J . M.: Transventricular Mitral Valvotomy, Surgery 46: 414, 1959. 16. Crum, H. B., and Tsapogas, M. J . C.: Transventricular Mitral Valvotomy: Report of 50 Consecutive Cases, Lancet 2: 880, 1959. 17. Edwards, W. S., Lyons, C , Thomas, H. D., and Clark, L. C : Management of Traumatic Mitral Insufficiency, Ann. Surg. 153: 822, 1961. 18. Gerbode, F . : Transventricular Mitral Valvotomy, Circulation 2 1 : 563, 1960. 19. Harken, D. E., Black, H., Taylor, W. J., Thrower, W. B., and Ellis, L. B . : Reoperation for Mitral Stenosis, Circulation 23: 7, 1961. 20. Kay, E. B., and Zimmermann, H. A.: Surgical Treatment of Mitral Stenosis: Open Versus Closed Technics, Am. J . Cardiol. 10: 1, 1962. 21. Kezdi, P., and Wessel, H. U.: Mitral Commissurotomy: Comparison of Clinical and Hemodynamic Results One to Three Years After Surgery, Am. J . Cardiol. 3 : 45, 1959. 22. Lenegre, J., and Coblenz, B . : L a commissurotomie mitrale, Arch. mal. coeur 46: 577, 1953. 23. Likoff, W., and Uricchio, J . F . : Results of Mitral Commissurotomy, J . A. M. A. 166: 737, 1958. 24. Logan, A.: The Transventricular Route for Mitral Valvulotomy, Kardiologia Polska 1: 49, 1957. 25. Logan, A., and Turner, R.: Surgical Treatment of Mitral Stenosis, Lancet 2: 874, 1959. 26. Logan, A., Lowther, C. P., and Turner, R. W. D.: Reoperation for Mitral Stenosis, Lancet 1: 443, 1962. 27. Morrow, A. G., and Braunwald, N . S.: Transventricular Mitral Commissurotomy, J . THORACIC SURG. 4 1 :
225,
1961.
28. Mounsey, P . : Determination of Success After Mitral Valvotomy, Brit. M. J . 2: 311, 1957. 29. Pe>ez-Alvarez, J . J . : Experience With the Beck Finger-Dilator in Mitral Valvulotomy, J . THORACIC SURG. 38: 186,
1959.
30. Ross, J . K . : Failed Mitral Valvotomy, Thorax 14: 320, 1959. 31. Runco, V., Molnar, W., Meokstroth, C. V., and Ryan, J . M.: The Graham-Steell Murmur Versus Aortic Regurgitation in Rheumatic Heart Disease: Results of Aortic Valvulography, Am. J . Med. 3 1 : 71, 1961. 32. Scannell, J . G., Burke, J . F., Saidi, F., and Turner, J . D . : Five-Year Follow-up Study of Closed Mitral Valvulotomy, J . THORACIC SURG. 40: 723, 1960. 33. Starr, A., and Edwards, M. L.: Mitral Replacement: Clinical Experience With a BallValve Prosthesis, Ann. Surg. 154: 726, 1961. 34. Turner, R. W. D., and Fraser, H. R. L.: Mitral Valvotomy, Lancet 2: 525 and 587, 1956.