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The natural history and surgical management of the redundant cusp syndrome (floppy mitral valve)
The natural history and surgical management of the redundant cusp syndrome (floppy mitral valve) The incidence of the redundant cusp syndrome ("floppy valve") was 5 per cent in 294 routine autopsies carried out at St. George's Hospital. The incidence increased linearly with age. The characteristic pathological features are expansion and thickening of the valve cusps with lengthening and weakening of the chordae tendineae. Fibrous disintegration begins at the tip of the fibrous core of the valve and spreads toward the annulus and into the chordae tendineae. The natural history of the redundant cusp syndrome is usually benign; however, in approximately 8 per cent of the patients, the valve deteriorates and rapidly progressive mitral regurgitation develops. We reviewed the presenting features and surgical management oj /6 patients with this syndrome treated at St. Thomas' Hospital between /965 and /972. The reasons for early deterioration in this series were ruptured chordae, subacute bacterial endocarditis, and associated connective tissue disease. The characteristic clinical features are a mid-systolic click and a late systolic murmur. However, when valve function deteriorates, the patient usually is in atrial fibrillation and has a pansystolic murmur, which makes the syndrome difficult to distinguish from other forms of mitral regurgitation. Fourteen patients in this series had mitral valve replacement with no operative mortality but one late death. None had paravalvular leaks and all are virtually asymptomatic. Two patients were treated by valvoplasty . Both have pansystolic murmurs and dyspnea.
D. G. Hill, F.R.C.S., F.R.A.C.S.,* M. J. Davies, M.R.C.S., L.R.C.P., M.C.Path.,** and M. V. Braimbridge, F.R.eS., London, England
he "floppy mitral valve" lesion is a degenerative process involving the valve leaflets.': " The chordae tendineae are weakened and may rupture. The syndrome is recognized clinically by a characteristic late systolic murmur and a mid-systolic click.":" Usually the natural history is benign, but in a small number of patients the condition of the valve may deteriorate and cause progressive mitral regurgitation. This paper considers the pathological features and natural history of the redundant cusp syndrome, together with the presentaReceived for publication Dec. 3, 1973. "Department of Cardiothoracic Surgery, SI. Thomas' Hospital, London. SEI, England. ""Department of Histopathology, St. George's Hospital, London, SWI. England.
tion and surgical management of patients whose valve condition deteriorated. Pathological features
The pathological features were studied in a postmortem series of 294 patients at St. George's Hospital by Dr. M. Davies. Floppy valves were found in 5 per cent of the 294 routine autopsy cases. The incidence increased linearly with age (Fig. 1). This pathology was not found in any patients younger than 40 years of age. In the fifth decade the incidence was 2.5 per cent; in the sixth and seventh decades, 4.7 per cent; in the eighth, 6 per cent; and in patients over 80 years of age, 8 per cent. The characteristic pathological feature of this syndrome is expansion and thickening
5 19
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Thoracic and Cardio va scular Surgery
~
0<
25
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z
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leaflet. There may be deposition of mucoid material, but this is variable (Figs. 4 and 5) .
D..
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Surgical series
100
u
z ~
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z
42
64
51-60
61-70
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33
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....z Q
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30
"'" upto40
I
41-50
71-80
80 and over
AGE IN YEARS
Fig. 1. Autopsy series (294 cases) conducted by Dr . M. Davies at St. George 's Hospital.
Fig. 2. Pathological specimen showing ballooned and thickened floppy valve viewed from the left atrium.
of the valve leaflets. They become balloon ed, heavy, and floppy (Fig . 2) . The chordae tendineae are attenuated, weakened, and prone to rupture. At a late stage a fibrous swelling may develop on the adjacent endocardial surface, which can aggregate with the chordae to form a fusion lesion. These lesions are thought to be due to friction from the elongated chordae' (Fig. 3). Microscopical evidence shows that it is a degenerati ve disease. The primary process is fibrous disintegration which begins at the tip of the fibrous core of a leaflet and extends outward toward the annulus and into the chordae tendinea e. Secondary thickening develops on the atrial surface of the
The natural history of the syndrome is usually benign. Most patients progress slowly and develop mitral regurgitation only late in life, but a small percentage show sudden early deter ioration." Any surgical series of patients who have the redundant cusp syndrome necessarily involves only those patients whose condition worsens. The reason for deterioration and the mode of presentation was studied in 16 patients with this syndrome who had mitral valve surgery at St. Thomas' Hospital between 1965 and 1972. Eleven patients (69 per cent) had early deterioration. All had ruptured chordae, 1 had had subacute bacterial endocarditis, and 2 had associated connective tissue disease. Six patients (31 per cent) developed mitral regurgitation late in life. Of the 11 patients in this series who had ruptured chordae, 10 had ruptured posterior chordae and presented with sudden onset of mitral regurgitation and swift deterioration. One patient had anterior chordal rupture, but this was limited to a few medial aberrant chordae. Bacterial endocarditis was unusual. In the 1 patient who had this complication , all of the posterior chordae were ruptured and vegetations were evident. The generalized connective tissue diseases often associated with this syndrome are cystic medial degeneration and osteogenesis imperfecta. There was no case of cystic medial degeneration in this series, but 2 patients had osteogenesis imperfecta. Clinical presentation of surgical series
The clinical presentation of these patients was on the whole classical. Twelve (75 per cent) had had a past history of a heart murmur for between 8 and 50 years, with an average of 26 years. In accordance with the natural history, two modes of presentation were found. Ten patients (62 per cent) , all those with posterior chordal rupture,
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Fig. 3. Pathological specimen showing floppy anterior and posterior cusps. The chordae of the anterior cusps have ruptured. A fusion .lesion is present on the endocardial surface under the posterior cusp.
presented with sudden onset of symptoms and rapid deterioration. Early surgery was necessary, the earliest after 2 months, The other 6 had a gradual onset of symptoms with insidious progression, the longest interval being 8 years. In these 6 patients, therefore, the disease could not be distinguished from other forms of mitral regurgitation. The average duration of symptoms for the whole group was 2 years. The predominant symptom was breathlessness, and all but 1 patient were in Class III according to the New York Heart Association classification. The usual clinical signs described in the redundant cusp syndrome (sinus rhythm, mid-systolic click, and late systolic murmur) were only infrequently found. Atrial fibrillation was present in 56 per cent of the patients, equally distributed between those with long and short histories. Only 1 patient had a mid-systolic click and a late systolic murmur. All the remainder had pansystolic murmurs when admitted for surgery and therefore could not be distinguished from patients with other forms of mitral regurgitation. Thirteen (81 per cent) had a third sound. The chest radiograms of these patients were compared with those of patients who
t---
ATRIAL SURFACE
LEFT VENTRICULAR OUTFLOW
-.. . . . . normal
PROCES S EXTENDS INTO CHORDAE
SECONDARY THICKENING OF ATRIAL SURFACE PRIMARY DISINTEGRATION OF FIBROSA BEGINS HERE : MUCOID DEPOSITS
Fig. 4. Diagram showing microscopic features of the floppy valve syndrome.
had mitral valve replacement for other reasons during the same period (Table I). Cardiac enlargement was, as expected, slightly less in those with the redundant cusp syndrome than in the other patientsmean cardiothoracic ratio 58 per cent as compared with 60 per cent. Left atrial enlargement was also somewhat less; 94 per
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Thoracic and Cardiovascular Surgery
Fig. 5. Electron micrograph of a redundant cusp showing paucity of collagen fibers and deposition in the interspaces of mucopolysaccharides.
cent had .Grade 1 or 2 enlargement as compared with 7 I per cent of those who had mitral valve replacement for other causes. The atrium was markedly enlarged in only 6 per cent of those with a redundant valve, as opposed to 29 per cent of the others. Cardiac catheterization was performed on all patients, but there were no distinguishing features. Results of surgery Fourteen patients had the mitral valve replaced with a Starr-Edwards prosthesis. These operations represented 8 per cent of all the mitral valve replacements carried out at St. Thomas' Hospital during this period. Mitral valvuloplasty was done for the other 2 patients with redundant valve syndrome (14 per cent of the valvuloplasties) . One valvuloplasty was carried out illadvisedly on the first patient in this series,
due to our inexperience with this condition. The second was performed on a patient with osteogenesis imperfecta in whom a blood coagulation defect was present and anticoagulants were contraindicated. Starr's standard technique was used for mitral valve replacement. Closely spaced interrupted sutures were passed through the valve annulus and then, as a vertical mattress stitch, through the prosthetic valve ring (Fig . 6) . More sutures than usual were used, an average of 42 in this series compared with 3 I for other types of mitral valve replacement. There were no operative deaths. One patient died 3 \/z years after the. operation from tracheal obstruction after an epistaxis while he was asleep. His anticoagulants at the time were well controlled. Morbidity included persistent ventricular ectopic beats in 6 patients. Two trache-
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Redundant cusp syndrome
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ostomies were performed on patients early in the series. The 2 patients with osteogenesis imperfecta had the anticipated bleeding problems postoperatively. All 15 surviving patients have been followed from 6 months to 6 years with an average of 2 years. Thirteen have no or trivial exercise intolerance. The patient who died after 3 1h years was asymptomatic. The 2 patients who had ill-advised valvuloplasties have definite exercise intolerance (Grades III or IV) and pansystolic murmurs. Discussion
The postmortem incidence of the redundant cusp (floppy valve) syndrome in this series was greater than has previously been described." This is partly due to the increased awareness of this syndrome, which has resulted in its being cited as a common cause of ruptured chordae and sometimes as a cause of sudden death. 111 The pathological features are characteristic. The basic process is fibrous degeneration, which begins at the tip of the fibrous core of a leaflet and extends toward the annulus and into the chordae tendineae. Mucoid deposition is variable. Secondary thickening develops on the atrial surface of the valve. These features can be contrasted with rheumatic mitral valve disease, in which there is an increase in fibrous tissue and vascularization of the leaflets. On the other hand, the so-called floppy aortic valves develop in response to dilatation of the aortic valve ring and microscopically show stretch lesions. These are fibrous deposits at the edges of the valve leaflets, which give a drumstick appearance in cross section. The natural history of the redundant cusp (floppy valve) syndrome is usually benign. The fact that the redundant cusp lesion is a common cause of slight mitral regurgitation is being recognized more frequently. The natural history of slight mitral regurgitation was studied in a long-term follow-up of 62 patients from 9 to 22 years (average 10.8 years) by Dr. A. Leatham's
valve
VERTICAL MATTRESS SUTURE
muscle
®
~ve muscle Fig. 6. Diagram showing vertical mattress suture technique for insertion of Starr-Edwards mitral valve.
Table I. Survey of redundant cusp syndrome at St. Thomas' Hospital (1965 to 1972) Chest x-ray evidence RCS
Cardiac enlargement (CTR) LA enlargement Grades I to 2 Grades 3 to 4
I Other MVR
51-66% 52-72% (mean 58%) (mean 66%) 94% 6%
71 % 29%
Legend: ReS, Redundant cusp syndrome. MVR, Mitral valve replacement. CTR, Cardiothoracic ratio. LA, Left atrial.
group" at S1. George's Hospital and the National Heart Hospital. These patients had isolated slight mitral regurgitation as manifested by a late systolic murmur, and 50 per cent had a mid-systolic click also. Only 8 per cent died or markedly deteriorated during the period of study. The causes of early deterioration are ruptured chordae, bacterial endocarditis, and associated connective tissue disease. Chordal rupture is the most common cause of deterioration, and in this series the posterior cusp was the most frequently involved. The reported incidence of chordal rupture in floppy mitral valves varies from
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30 to 82 per cent.l'"?" Recent observations on the anatomy of chordae tendineae and their attachment to the mitral leaflets have shown that there are four types of chordae, distinguished by their mode of insertion. On the anterior leaflet are two chordae that are by far the thickest and largest of the whole mitral valve. These "strut" chordae maintain the integrity of the anterior leaflet. The posterior leaflet does not have "strut" chordae, and in general its chordae are shorter and thinner than those of the anterior leaflet," which may explain the greater frequency of rupture of the posterior cusp chordae. " Anterior chordal rupture may occur more frequently than this series would suggest, possibly because it is associated with sudden death and therefore seen in coroner's autopsies!"; apparently, rupture of the anterior chordae is more catastrophic to mitral valve function than is posterior chordal rupture, as might be expected from the relative size of the cusps."; Bacterial endocarditis is probably only an infrequent complication." The reported incidence is from 3 to 30 per cent. G, 8. 10, 11 There was only I such patient in this series. The explanation for the predisposition to bacterial endocarditis is that underlying fibrosal changes result in stretching and loss of endothelial continuity on the valve surface. This invites deposition of fibrin and so provides a nidus for infection." The generalized connective tissue diseases often associated with this syndrome are cystic medial degeneration and osteogenesis imperfecta. 10, 18-~0 These conditions produce weakening of the valve annulus. It is important to distinguish the pathological features of these conditions from those of the redundant cusp syndrome itself. The increased strain produced by the heavy, floppy cusps sum mates with the effects of the weakened annulus to produce dilatation and early regurgitation. The characteristic clinical features of the redundant cusp syndrome are a mid-systolic click and a late systolic murmur presenting as slight mitral regurgitation. 4-{;, ~1 The
presentation of patients whose condition deteriorates is related to the natural history. Usually there is a past history of a heart murmur. Those with ruptured chordae present with sudden onset of symptoms, while the remainder have a slowly progressive disease and are usually elderly. The onset of atrial fibrillation may aggravate the symptoms. 1 On admission for operation, most patients have severe mitral regurgitation and therefore have pansystolic murmurs. These symptoms are often difficult to distinguish from other causes of mitral regurgitation. Investigatory procedures are usually not diagnostic although ruptured chordae may produce typical angiographic features. ~~. ":J Patients presenting with rapidly deteriorating mitral regurgitation can be treated surgically by either mitral valve replacement'" '". "4. OC, or mitral valvuloplasty.":" The patients who had mitral valvuloplasties in this series still have definite effort intolerance and pansystolic murmurs. Mitral valvuloplasty does not cure mitral regurgitation in this condition and is therefore not recommended as the treatment of choice. There is a high reported incidence of prosthetic valve dehiscence in the redundant cusp syndrome (8 per cent) ." Several operative techniques have been described to prevent this problem. These include the use of interrupted rather than continuous sutures, Teflon felt pledgets to support sutures, and placement of the prosthesis below the mitral annulus.": '",:n In this series vertical mattress sutures were used to obtain maximal depth of contact between the sewing ring and the flimsy valve annulus. 'Many more sutures were used than is normal in replacement of rheumatic mitral valves, and there were no postoperative paravalvular leaks. 1\
REFERENCES Frable, W. J.: Mucinous Degeneration of the Cardiac Valves: The "Floppy Valve" Syndrome, J. THORAc. CARDIOVASC. SURG. 58: 62, 1969. 2 Davis, R. H., Schuster, B., Knoebel, S. B., and Fisch, C.: Myxomatous Degeneration of
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3
4
5
6
7
8
9
10
11
12
13
14
15 16 17
the Mitral Valve, Am. J. Cardio!. 28: 449, 1971. Epstein, E. I., and Coulshed, N.: Phonocardiogram and Apex Cardiogram in Systolic Click: Late Systolic Murmur Syndrome, Br. Heart J. 35: 260, 1973. Hutter, A. M., Jr., Dinsmore, R. E., WilIerson, J. T., and DeSanctis, R. W.: Early Systolic Clicks Due to Mitral Valve Prolapse, Circulation 44: 516, 1971. Behar, V. S., Whalen, R. E., and McIntosh, H. D.: The Ballooning Mitral Valve in Patients With the "Precordial Honk" or "Whoop," Am. J. Cardio!. 20: 789, 1967. Shell, W. E., Walton, J. A., Clifford, M. E., and Willis, P. W.: The Familial Occurrence of the Syndrome of Mid-late Systolic Click and Late Systolic Murmur, Circulation 39: 327, 1969. Salazar, A. F., and Edwards, J. E.: Friction Lesions of Ventricular Endocardium: Relation to Chordae Tendineae of Mitral Valve, Arch. Pathol. (Chicago) 90: 364, 1970. Allen, H., Harris, A., and Leatham, A.: The Natural History of Slight Mitral Regurgitation. Paper delivered to British Cardiac Society, 1972. Pomerance, A.: Ballooning Deformity (Mucoid Degeneration) of Atrioventricular Valves, Br. Heart J. 31: 343, 1969. McKay, R., and Yacoub, M. H.: Clinical and Pathological Findings in Patients With "Floppy" Valves Treated Surgically, Circulation 47, 48: 63, 1973 (Suppl, III). Read, R. C., and ThaI, A. P.: Surgical Experience With Symptomatic Myxomatous Valvular Transformation (The Floppy Valve Snydrome), Surgery 59: 173, 1966. Cooley, D. A., Gerami, S., Hallman, G. L., Wukasch, D. C., and Hall, R. J.: Mitral Insufficiency Due to Myxomatous Transformation: "Floppy Valve Syndrome," J. Cardiovase. Surg. 13: 346, 1972. Lam, J. H. C., Ranganathan, N., Wigle, E. D., and Silver, M. D.: Morphology of the Human Mitral Valve. 1. Chordae Tendineae: A New Classification, Circulation 41: 449, 1970. Littler, W. A., Epstein, E. J., and Coulshed, N.: Acute Mitral Regurgitation Resulting From Ruptured or Elongated Chordae Tendineae. Q. J. Med. 42: 87, 1973. Davies, M. J.: Personal communication. Guiliani, E. R.: Mitral Valve Incompetence Due to Flail Anterior Leaflet: A New Physical Sign, Am. J. Cardiol. 20: 784, 1967. Klughaupt, M., Flamm, M. D., Hancock, E. W., and Harrison, D. C.: Nonrheumatic Mitral Insufficiency: Determination of Operability
and Prognosis, Circulation 39: 307, 1969. 18 Bowers, D.: Primary Abnormalities of the Mitral Valve in Marian's Syndrome: Electrographic Findings, Br. Heart J. 31: 676, 1969. 19 Bittar, N., and Sosa, J. A.: The Billowing Mitral Valve Leaflet: Report on Fourteen Patients, Circulation 38: 763, 1968. 20 Wood, S. J., Thomas, J., and Braimbridge, M. V.: Mitral Valve Disease and Open Heart Surgery in Osteogenesis Imperfecta Tarda, Br. Heart J. 35: 103, 1973. 21 Rizzon, P., Biasco, G., Brindicci, G., and Mauro, F.: Familial Syndrome of Mid-systolic Click and Late Systolic Murmur, Br. Heart J. 35: 245, 1973. 22 Wexler, L., Silverman, J. F., DeBusk, R. F., and Harrison, D. C.: Angiographic Features of Rheumatic and Nonrheumatic Mitral Regurgitation, Circulation 44: 1080, 1971. 23 Stannard, M., Sloman, J. G., Hare, W. S. C., and Goble, A. J.: Prolapse of the Posterior Leaflet of the Mitral Valve: A Clinical, Familial and Cineangiographic Study, Br. Med. J. 3: 71, 1967. 24 Sanders, C. A., Austen, W. G., Harthorne, J. W., Dinsmore, R. E., and Scannell, J. G.: Diagnosis and Surgical Treatment of Mitral Regurgitation Secondary to Ruptured Chordae Tendineae, N. Eng!. J. Med. 276: 943, 1967. 25 Yacoub, M. H., and Kittle, C. F.: A New Technique for Replacement of the Mitral Valve by a Semilunar Valve Homograft, J. THoRAc. CARDIOVASC. SURG. 58: 859, 1969. 26 Gerbode, F., Kerth, W. J., and Puryear, G. H.: The Surgery of Non-rheumatic Acquired Insufficiency of the Mitral Valve, Progress in Cardiovasc. Dis. 11: 173, 1968. 27 Monk, I., Donnelly, G. L., and Deal, C.: Repair of the Mitral Valve After Rupture of Chordae Tendineae, Med. J. Aust. 2: 902, 1970. 28 Gerbode, F., Hill, J. D., Kelly, J. J., Jr., SeIzer, A., and Kerth, W. J.: Surgical Correction of Mitral Insufficiency Due to Ruptured Chordae Tendineae, Circulation 37, 38: 119, 1968 (Suppl, II). 29 McGoon, D. C.: Repair of Mitral Insufficiency Due to Ruptured Chordae Tendineae, J. THORAC. CARDIOVASC. SURG. 39: 357, 1960. 30 Morris, J. D., Penner, D. A., and Brandt, R. L.: Surgical Correction of Ruptured Chordae Tendineae, 1. THoRAc. CARDIOVASC. SURG. 48: 772, 1964. 31 Weldon, C. S., Krause, A. H., Parker, B. M., Clark, R. E., and Roper, C. L.: Clinical Recognition and Surgical Management of Acute Disruption of the Mitral Valve, Ann. Surg. 175: 1000, 1972.
D. G. Hill, F.R.C.S., F.R.A.C.S.,* M. J. Davies, M.R.C.S., L.R.C.P., M.C.Path.,** and M. V. Braimbridge, F.R.eS., London, England
he "floppy mitral valve" lesion is a degenerative process involving the valve leaflets.': " The chordae tendineae are weakened and may rupture. The syndrome is recognized clinically by a characteristic late systolic murmur and a mid-systolic click.":" Usually the natural history is benign, but in a small number of patients the condition of the valve may deteriorate and cause progressive mitral regurgitation. This paper considers the pathological features and natural history of the redundant cusp syndrome, together with the presentaReceived for publication Dec. 3, 1973. "Department of Cardiothoracic Surgery, SI. Thomas' Hospital, London. SEI, England. ""Department of Histopathology, St. George's Hospital, London, SWI. England.
tion and surgical management of patients whose valve condition deteriorated. Pathological features
The pathological features were studied in a postmortem series of 294 patients at St. George's Hospital by Dr. M. Davies. Floppy valves were found in 5 per cent of the 294 routine autopsy cases. The incidence increased linearly with age (Fig. 1). This pathology was not found in any patients younger than 40 years of age. In the fifth decade the incidence was 2.5 per cent; in the sixth and seventh decades, 4.7 per cent; in the eighth, 6 per cent; and in patients over 80 years of age, 8 per cent. The characteristic pathological feature of this syndrome is expansion and thickening
5 19
The Journal of
5 20
Hill, Davies, Braimbridge
Thoracic and Cardio va scular Surgery
~
0<
25
Q
z
>Vl
leaflet. There may be deposition of mucoid material, but this is variable (Figs. 4 and 5) .
D..
Vl
:::>
Surgical series
100
u
z ~
ce Q
z
42
64
51-60
61-70
:::>
.... Q
0<
33
l:5
.... u
....z Q
U
~
30
"'" upto40
I
41-50
71-80
80 and over
AGE IN YEARS
Fig. 1. Autopsy series (294 cases) conducted by Dr . M. Davies at St. George 's Hospital.
Fig. 2. Pathological specimen showing ballooned and thickened floppy valve viewed from the left atrium.
of the valve leaflets. They become balloon ed, heavy, and floppy (Fig . 2) . The chordae tendineae are attenuated, weakened, and prone to rupture. At a late stage a fibrous swelling may develop on the adjacent endocardial surface, which can aggregate with the chordae to form a fusion lesion. These lesions are thought to be due to friction from the elongated chordae' (Fig. 3). Microscopical evidence shows that it is a degenerati ve disease. The primary process is fibrous disintegration which begins at the tip of the fibrous core of a leaflet and extends outward toward the annulus and into the chordae tendinea e. Secondary thickening develops on the atrial surface of the
The natural history of the syndrome is usually benign. Most patients progress slowly and develop mitral regurgitation only late in life, but a small percentage show sudden early deter ioration." Any surgical series of patients who have the redundant cusp syndrome necessarily involves only those patients whose condition worsens. The reason for deterioration and the mode of presentation was studied in 16 patients with this syndrome who had mitral valve surgery at St. Thomas' Hospital between 1965 and 1972. Eleven patients (69 per cent) had early deterioration. All had ruptured chordae, 1 had had subacute bacterial endocarditis, and 2 had associated connective tissue disease. Six patients (31 per cent) developed mitral regurgitation late in life. Of the 11 patients in this series who had ruptured chordae, 10 had ruptured posterior chordae and presented with sudden onset of mitral regurgitation and swift deterioration. One patient had anterior chordal rupture, but this was limited to a few medial aberrant chordae. Bacterial endocarditis was unusual. In the 1 patient who had this complication , all of the posterior chordae were ruptured and vegetations were evident. The generalized connective tissue diseases often associated with this syndrome are cystic medial degeneration and osteogenesis imperfecta. There was no case of cystic medial degeneration in this series, but 2 patients had osteogenesis imperfecta. Clinical presentation of surgical series
The clinical presentation of these patients was on the whole classical. Twelve (75 per cent) had had a past history of a heart murmur for between 8 and 50 years, with an average of 26 years. In accordance with the natural history, two modes of presentation were found. Ten patients (62 per cent) , all those with posterior chordal rupture,
Volume 67
Redundant cusp syndrome
Number 4 April, 1974
52 1
Fig. 3. Pathological specimen showing floppy anterior and posterior cusps. The chordae of the anterior cusps have ruptured. A fusion .lesion is present on the endocardial surface under the posterior cusp.
presented with sudden onset of symptoms and rapid deterioration. Early surgery was necessary, the earliest after 2 months, The other 6 had a gradual onset of symptoms with insidious progression, the longest interval being 8 years. In these 6 patients, therefore, the disease could not be distinguished from other forms of mitral regurgitation. The average duration of symptoms for the whole group was 2 years. The predominant symptom was breathlessness, and all but 1 patient were in Class III according to the New York Heart Association classification. The usual clinical signs described in the redundant cusp syndrome (sinus rhythm, mid-systolic click, and late systolic murmur) were only infrequently found. Atrial fibrillation was present in 56 per cent of the patients, equally distributed between those with long and short histories. Only 1 patient had a mid-systolic click and a late systolic murmur. All the remainder had pansystolic murmurs when admitted for surgery and therefore could not be distinguished from patients with other forms of mitral regurgitation. Thirteen (81 per cent) had a third sound. The chest radiograms of these patients were compared with those of patients who
t---
ATRIAL SURFACE
LEFT VENTRICULAR OUTFLOW
-.. . . . . normal
PROCES S EXTENDS INTO CHORDAE
SECONDARY THICKENING OF ATRIAL SURFACE PRIMARY DISINTEGRATION OF FIBROSA BEGINS HERE : MUCOID DEPOSITS
Fig. 4. Diagram showing microscopic features of the floppy valve syndrome.
had mitral valve replacement for other reasons during the same period (Table I). Cardiac enlargement was, as expected, slightly less in those with the redundant cusp syndrome than in the other patientsmean cardiothoracic ratio 58 per cent as compared with 60 per cent. Left atrial enlargement was also somewhat less; 94 per
The Journal of
522
Hill, Davies, Braimbridge
Thoracic and Cardiovascular Surgery
Fig. 5. Electron micrograph of a redundant cusp showing paucity of collagen fibers and deposition in the interspaces of mucopolysaccharides.
cent had .Grade 1 or 2 enlargement as compared with 7 I per cent of those who had mitral valve replacement for other causes. The atrium was markedly enlarged in only 6 per cent of those with a redundant valve, as opposed to 29 per cent of the others. Cardiac catheterization was performed on all patients, but there were no distinguishing features. Results of surgery Fourteen patients had the mitral valve replaced with a Starr-Edwards prosthesis. These operations represented 8 per cent of all the mitral valve replacements carried out at St. Thomas' Hospital during this period. Mitral valvuloplasty was done for the other 2 patients with redundant valve syndrome (14 per cent of the valvuloplasties) . One valvuloplasty was carried out illadvisedly on the first patient in this series,
due to our inexperience with this condition. The second was performed on a patient with osteogenesis imperfecta in whom a blood coagulation defect was present and anticoagulants were contraindicated. Starr's standard technique was used for mitral valve replacement. Closely spaced interrupted sutures were passed through the valve annulus and then, as a vertical mattress stitch, through the prosthetic valve ring (Fig . 6) . More sutures than usual were used, an average of 42 in this series compared with 3 I for other types of mitral valve replacement. There were no operative deaths. One patient died 3 \/z years after the. operation from tracheal obstruction after an epistaxis while he was asleep. His anticoagulants at the time were well controlled. Morbidity included persistent ventricular ectopic beats in 6 patients. Two trache-
Volume 67
Redundant cusp syndrome
Number 4
523
April,1974
ostomies were performed on patients early in the series. The 2 patients with osteogenesis imperfecta had the anticipated bleeding problems postoperatively. All 15 surviving patients have been followed from 6 months to 6 years with an average of 2 years. Thirteen have no or trivial exercise intolerance. The patient who died after 3 1h years was asymptomatic. The 2 patients who had ill-advised valvuloplasties have definite exercise intolerance (Grades III or IV) and pansystolic murmurs. Discussion
The postmortem incidence of the redundant cusp (floppy valve) syndrome in this series was greater than has previously been described." This is partly due to the increased awareness of this syndrome, which has resulted in its being cited as a common cause of ruptured chordae and sometimes as a cause of sudden death. 111 The pathological features are characteristic. The basic process is fibrous degeneration, which begins at the tip of the fibrous core of a leaflet and extends toward the annulus and into the chordae tendineae. Mucoid deposition is variable. Secondary thickening develops on the atrial surface of the valve. These features can be contrasted with rheumatic mitral valve disease, in which there is an increase in fibrous tissue and vascularization of the leaflets. On the other hand, the so-called floppy aortic valves develop in response to dilatation of the aortic valve ring and microscopically show stretch lesions. These are fibrous deposits at the edges of the valve leaflets, which give a drumstick appearance in cross section. The natural history of the redundant cusp (floppy valve) syndrome is usually benign. The fact that the redundant cusp lesion is a common cause of slight mitral regurgitation is being recognized more frequently. The natural history of slight mitral regurgitation was studied in a long-term follow-up of 62 patients from 9 to 22 years (average 10.8 years) by Dr. A. Leatham's
valve
VERTICAL MATTRESS SUTURE
muscle
®
~ve muscle Fig. 6. Diagram showing vertical mattress suture technique for insertion of Starr-Edwards mitral valve.
Table I. Survey of redundant cusp syndrome at St. Thomas' Hospital (1965 to 1972) Chest x-ray evidence RCS
Cardiac enlargement (CTR) LA enlargement Grades I to 2 Grades 3 to 4
I Other MVR
51-66% 52-72% (mean 58%) (mean 66%) 94% 6%
71 % 29%
Legend: ReS, Redundant cusp syndrome. MVR, Mitral valve replacement. CTR, Cardiothoracic ratio. LA, Left atrial.
group" at S1. George's Hospital and the National Heart Hospital. These patients had isolated slight mitral regurgitation as manifested by a late systolic murmur, and 50 per cent had a mid-systolic click also. Only 8 per cent died or markedly deteriorated during the period of study. The causes of early deterioration are ruptured chordae, bacterial endocarditis, and associated connective tissue disease. Chordal rupture is the most common cause of deterioration, and in this series the posterior cusp was the most frequently involved. The reported incidence of chordal rupture in floppy mitral valves varies from
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30 to 82 per cent.l'"?" Recent observations on the anatomy of chordae tendineae and their attachment to the mitral leaflets have shown that there are four types of chordae, distinguished by their mode of insertion. On the anterior leaflet are two chordae that are by far the thickest and largest of the whole mitral valve. These "strut" chordae maintain the integrity of the anterior leaflet. The posterior leaflet does not have "strut" chordae, and in general its chordae are shorter and thinner than those of the anterior leaflet," which may explain the greater frequency of rupture of the posterior cusp chordae. " Anterior chordal rupture may occur more frequently than this series would suggest, possibly because it is associated with sudden death and therefore seen in coroner's autopsies!"; apparently, rupture of the anterior chordae is more catastrophic to mitral valve function than is posterior chordal rupture, as might be expected from the relative size of the cusps."; Bacterial endocarditis is probably only an infrequent complication." The reported incidence is from 3 to 30 per cent. G, 8. 10, 11 There was only I such patient in this series. The explanation for the predisposition to bacterial endocarditis is that underlying fibrosal changes result in stretching and loss of endothelial continuity on the valve surface. This invites deposition of fibrin and so provides a nidus for infection." The generalized connective tissue diseases often associated with this syndrome are cystic medial degeneration and osteogenesis imperfecta. 10, 18-~0 These conditions produce weakening of the valve annulus. It is important to distinguish the pathological features of these conditions from those of the redundant cusp syndrome itself. The increased strain produced by the heavy, floppy cusps sum mates with the effects of the weakened annulus to produce dilatation and early regurgitation. The characteristic clinical features of the redundant cusp syndrome are a mid-systolic click and a late systolic murmur presenting as slight mitral regurgitation. 4-{;, ~1 The
presentation of patients whose condition deteriorates is related to the natural history. Usually there is a past history of a heart murmur. Those with ruptured chordae present with sudden onset of symptoms, while the remainder have a slowly progressive disease and are usually elderly. The onset of atrial fibrillation may aggravate the symptoms. 1 On admission for operation, most patients have severe mitral regurgitation and therefore have pansystolic murmurs. These symptoms are often difficult to distinguish from other causes of mitral regurgitation. Investigatory procedures are usually not diagnostic although ruptured chordae may produce typical angiographic features. ~~. ":J Patients presenting with rapidly deteriorating mitral regurgitation can be treated surgically by either mitral valve replacement'" '". "4. OC, or mitral valvuloplasty.":" The patients who had mitral valvuloplasties in this series still have definite effort intolerance and pansystolic murmurs. Mitral valvuloplasty does not cure mitral regurgitation in this condition and is therefore not recommended as the treatment of choice. There is a high reported incidence of prosthetic valve dehiscence in the redundant cusp syndrome (8 per cent) ." Several operative techniques have been described to prevent this problem. These include the use of interrupted rather than continuous sutures, Teflon felt pledgets to support sutures, and placement of the prosthesis below the mitral annulus.": '",:n In this series vertical mattress sutures were used to obtain maximal depth of contact between the sewing ring and the flimsy valve annulus. 'Many more sutures were used than is normal in replacement of rheumatic mitral valves, and there were no postoperative paravalvular leaks. 1\
REFERENCES Frable, W. J.: Mucinous Degeneration of the Cardiac Valves: The "Floppy Valve" Syndrome, J. THORAc. CARDIOVASC. SURG. 58: 62, 1969. 2 Davis, R. H., Schuster, B., Knoebel, S. B., and Fisch, C.: Myxomatous Degeneration of
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the Mitral Valve, Am. J. Cardio!. 28: 449, 1971. Epstein, E. I., and Coulshed, N.: Phonocardiogram and Apex Cardiogram in Systolic Click: Late Systolic Murmur Syndrome, Br. Heart J. 35: 260, 1973. Hutter, A. M., Jr., Dinsmore, R. E., WilIerson, J. T., and DeSanctis, R. W.: Early Systolic Clicks Due to Mitral Valve Prolapse, Circulation 44: 516, 1971. Behar, V. S., Whalen, R. E., and McIntosh, H. D.: The Ballooning Mitral Valve in Patients With the "Precordial Honk" or "Whoop," Am. J. Cardio!. 20: 789, 1967. Shell, W. E., Walton, J. A., Clifford, M. E., and Willis, P. W.: The Familial Occurrence of the Syndrome of Mid-late Systolic Click and Late Systolic Murmur, Circulation 39: 327, 1969. Salazar, A. F., and Edwards, J. E.: Friction Lesions of Ventricular Endocardium: Relation to Chordae Tendineae of Mitral Valve, Arch. Pathol. (Chicago) 90: 364, 1970. Allen, H., Harris, A., and Leatham, A.: The Natural History of Slight Mitral Regurgitation. Paper delivered to British Cardiac Society, 1972. Pomerance, A.: Ballooning Deformity (Mucoid Degeneration) of Atrioventricular Valves, Br. Heart J. 31: 343, 1969. McKay, R., and Yacoub, M. H.: Clinical and Pathological Findings in Patients With "Floppy" Valves Treated Surgically, Circulation 47, 48: 63, 1973 (Suppl, III). Read, R. C., and ThaI, A. P.: Surgical Experience With Symptomatic Myxomatous Valvular Transformation (The Floppy Valve Snydrome), Surgery 59: 173, 1966. Cooley, D. A., Gerami, S., Hallman, G. L., Wukasch, D. C., and Hall, R. J.: Mitral Insufficiency Due to Myxomatous Transformation: "Floppy Valve Syndrome," J. Cardiovase. Surg. 13: 346, 1972. Lam, J. H. C., Ranganathan, N., Wigle, E. D., and Silver, M. D.: Morphology of the Human Mitral Valve. 1. Chordae Tendineae: A New Classification, Circulation 41: 449, 1970. Littler, W. A., Epstein, E. J., and Coulshed, N.: Acute Mitral Regurgitation Resulting From Ruptured or Elongated Chordae Tendineae. Q. J. Med. 42: 87, 1973. Davies, M. J.: Personal communication. Guiliani, E. R.: Mitral Valve Incompetence Due to Flail Anterior Leaflet: A New Physical Sign, Am. J. Cardiol. 20: 784, 1967. Klughaupt, M., Flamm, M. D., Hancock, E. W., and Harrison, D. C.: Nonrheumatic Mitral Insufficiency: Determination of Operability
and Prognosis, Circulation 39: 307, 1969. 18 Bowers, D.: Primary Abnormalities of the Mitral Valve in Marian's Syndrome: Electrographic Findings, Br. Heart J. 31: 676, 1969. 19 Bittar, N., and Sosa, J. A.: The Billowing Mitral Valve Leaflet: Report on Fourteen Patients, Circulation 38: 763, 1968. 20 Wood, S. J., Thomas, J., and Braimbridge, M. V.: Mitral Valve Disease and Open Heart Surgery in Osteogenesis Imperfecta Tarda, Br. Heart J. 35: 103, 1973. 21 Rizzon, P., Biasco, G., Brindicci, G., and Mauro, F.: Familial Syndrome of Mid-systolic Click and Late Systolic Murmur, Br. Heart J. 35: 245, 1973. 22 Wexler, L., Silverman, J. F., DeBusk, R. F., and Harrison, D. C.: Angiographic Features of Rheumatic and Nonrheumatic Mitral Regurgitation, Circulation 44: 1080, 1971. 23 Stannard, M., Sloman, J. G., Hare, W. S. C., and Goble, A. J.: Prolapse of the Posterior Leaflet of the Mitral Valve: A Clinical, Familial and Cineangiographic Study, Br. Med. J. 3: 71, 1967. 24 Sanders, C. A., Austen, W. G., Harthorne, J. W., Dinsmore, R. E., and Scannell, J. G.: Diagnosis and Surgical Treatment of Mitral Regurgitation Secondary to Ruptured Chordae Tendineae, N. Eng!. J. Med. 276: 943, 1967. 25 Yacoub, M. H., and Kittle, C. F.: A New Technique for Replacement of the Mitral Valve by a Semilunar Valve Homograft, J. THoRAc. CARDIOVASC. SURG. 58: 859, 1969. 26 Gerbode, F., Kerth, W. J., and Puryear, G. H.: The Surgery of Non-rheumatic Acquired Insufficiency of the Mitral Valve, Progress in Cardiovasc. Dis. 11: 173, 1968. 27 Monk, I., Donnelly, G. L., and Deal, C.: Repair of the Mitral Valve After Rupture of Chordae Tendineae, Med. J. Aust. 2: 902, 1970. 28 Gerbode, F., Hill, J. D., Kelly, J. J., Jr., SeIzer, A., and Kerth, W. J.: Surgical Correction of Mitral Insufficiency Due to Ruptured Chordae Tendineae, Circulation 37, 38: 119, 1968 (Suppl, II). 29 McGoon, D. C.: Repair of Mitral Insufficiency Due to Ruptured Chordae Tendineae, J. THORAC. CARDIOVASC. SURG. 39: 357, 1960. 30 Morris, J. D., Penner, D. A., and Brandt, R. L.: Surgical Correction of Ruptured Chordae Tendineae, 1. THoRAc. CARDIOVASC. SURG. 48: 772, 1964. 31 Weldon, C. S., Krause, A. H., Parker, B. M., Clark, R. E., and Roper, C. L.: Clinical Recognition and Surgical Management of Acute Disruption of the Mitral Valve, Ann. Surg. 175: 1000, 1972.