CLINICAL STUDIES
Dilatation of the Mitral Anulus A Rare Cause of Mitral Regurgitation
BERNADINE H. BULKLEY, M.D.* WILLIAM C. ROBERTS, M.D. Baltimore, Matyland
From the Section of Pathology, National Heart & Lung institute, Natlonal Institutes of Health, Bethesda.Maryland 20014. Requests for reprints should be addressed to Dr. William C. Roberts, Ma. 10A. Rm. 3E30. National Institutes of He&h, Bethesda, Marykd 20014. Manuscript accepted January 22, 1975. * Present address: Department of Medicine, Division of Cardiology, The Johns Hopkins Hospital. Baltimore, Maryland.
To confirm or deny the thesis that mitral anular dllatatlon Is a cause of mitral regurgttatlon, this anulus was measured In 102 patients, 24 of whom had normal hearts and 78 of whom had dllated lefl ventricles, some associated with mitral regurgitation, others not. The circumference of the mitral anulus in the 24 patients with normal hearts averaged 9 cm (range 7 to 11 cm); In 24 patients with idiopathic card&myopathy of the ventricular dilated type, both wlth (12 patients) and without (12 patlents) mild to moderate regurgitation, 11 cm (range 10 to 14 cm); and in 31 patients with severe mttral regurgitation, 12 cm (range 8 to 18 cm). Among the latter 31 patients with severe m&al regurgltation, the anuius was only mlklly dilated in the 15 wlth rheumatic disease (average 11 cm) and in the SIX with ruptured chordae tendineae on prevloudy normal valves (average 10 cm); in contrast, In the 10 patients wlth floppy mitral valves with or without the Marfan syndrome the mitral anulus was greatly dilated (average 15.5 cm). Thus, only In patients with floppy valves wlth or without the Marfan syndrome or both does anular dtlatation by ltself appear great enough to cause mitral regurgttatlon. It appears, therefore, that dilatation of the mitral anulus Is a rare cause of mitral regurghatlon and that abnormality of the fibrous sketeton of the heart Is necessary for the mitral anulus to dilate enough to cause mitral regurgitation. Although believed for many years to be an important cause of mitral regurgitation, anular dilatation today is considered an infrequent cause. Surprisingly, supportive anatomic evidence for or against this view is lacking. To reexamine this concept, the mitral anulus and other left ventricular dimensions were measured in 102 human hearts, including some with and some without mitral regurgitation. METHODS
AND
DESCRIPTION
From among approximately
2,500
ditions on file in the Pathology
&
PATIENTS
STUDfED
hearts with various cardiovascular
Laboratory
of the National
con-
Heart and Lung
Institute, 78 recently accessioned hearts (all in patients greater than 14 years of age) with dilated left ventricles were selected for study. Only well
October 1975
The Amerkan Journal ol Medklne
Vohnne 59
457
DILATATION OF MITRAL ANULUS-BULKLEY,
ROBERTS
preserved hearts in which few histologic sections had been taken, or extraneous cuts made, were utilized. The measurements in each of the 102 hearts were performed separately by each of us. In addition to measuring the circumferences of the mitral anuli, several other left ventricular dimensions were measured (Figure 1): left ventricular length; the distance from the base of right anterior aortic valve cusp to the apex or the distance from the anulus behind the posterior mitral leaflet to the apex; and left ventricular circumference interiorly, at its base and midway between its base and apex. The 24 patients with normal hearts ranged in age from 19 to 69 years (average 43 years), and the 78 patients with abnormal hearts, from 15 to 78 years (average 41 years) (Table I). The latter 78 patients were divided into three major groups depending on the presence or ab-
sence of mitral regurgitation (Tables II and Ill): 23 patients without mitral regurgitation; 24 patients with idiopathic cardiomyopathy of the ventricular dilated type [I] who may or may not have had mitral regurgitation: and 31 patients with mitral regurgitation of varying etiology. Cardiac catheterization, including measurement of left ventricular pressures, and left ventricular angiographic studies were performed in 48 of the 78 patients: in 16 of 23 without mitral regurgitation, in three of 24 with cardiomyopathy and in 29 of 31 with mitral regurgitation. None of the 78 patients had stenotic valvular lesions. Aortic regurgitation was present in 14 of the 23 patients without mitral regurgitation, in none of the 24 with cardiomyopathy and in three of the 21 with mitral regurgitation (Table I). Of the 23 patients without mitral regurgitation, 10 had pure aortic regurgitation of non-Marfan etiology [2] (Figure 2), seven had floppy mitral valves (all incidental necropsy findings because none had had precordial murmurs) [2],
Figure 1. Left ventricular dimensions. The upper left diagram is a longitudinal view of the left ventricle, and the specimen itself is shown in the lower left. The upper right diagram is a view of left ventricle (L V) at its base, and the specimen itself after removal of the atria and right ventricle is shown in the lower right. The anterior mitral leaflet (A) divides the left ventricular cavify into inflow and outflow tracts. Measurements were made of the circumferences of the mitral anulus (b to c [upper left]; b to b via c [upper right]). The LV base (a to c through b [upper left]; a back to a via b, c and b [upper right]); the ma-portion of the LV id to e luooer left]) and the‘length’of’LV from base to apex (a to f via d or c to f via e [upper
left]). 458
October 1075
The Amerkan Journal of Medklne
Vdunw 59
DILATATION
and six had the Marfan aortic regurgitation
syndrome
[2],
five of whom
murmurs three
dilated type (Figure strongly suggestive
of them
the mitral
left ventricular described The
angiography.
patients
chordae
fan syndrome tion was
mitral
regurgitation
regurgitation
(Figure
secondary
with rheumatic,
II
Studied
Patients Studied
included secondary
mitral
over many years
Left Ventricular
to
valves to flop-
mitral regurgitaassociated
[2]. Mitral regurgitation
floppy and Marfan
15
with the Mar-
leaflets
appears
Dimensions
Range
24 19-69 78 15-78 10 39-56 7 18-67 6 21-48 24 21-66 15 16-40 6 20-62 6 41-78 4 15-31 ___.
43 41 47 54 36 45 25 44 54 24
11 48 9 3 5 17 3 2 5 4
13 30
0 17 10 0 4 0 0 0 0 3
1 4 1 7 12 4 1 0
.._______~ ~.~..~~~..
0 43 0 0 0 12 15 6 6 4
~_
NOTE: AR = aortic regurgitation; floppy = floppy mitral valves; CM = cardiomyopathy; CT = chordae tendineae; MR = mitral regurgitation.
in the 25 patients
etiologies,
No.
Normal hearts Abnormal hearts Pure AR Floppy Marfan CM Rheumatic Ruptured CT Floppy Marfan __~~~~_____
etiology (Fig-
was secondary
5) and four whose
syndrome
Fe- No. No. Aver- Male male with with age (no.) (no.) AR MR
by
was not
normal
unassociated
to floppy
to have been present
was
on previously
mitral leaflets
with the Marfan
Data on Patients Ages (yr)
and in
confirmed
murmur
was of rheumatic
[ 31, six whose mitral regurgitation
TABLE
was
A precordiat
tendineae
py or prolapsing
Clinical
of the
of mitral regurgitation,
with mitral
six whose
ruptured
I
12 had had precordial
regurgitation
mitral regurgitation
ure 4)
3)
in any of the other 12 patients.
31
whose
TABLE
BULKI EY. ROBERTS
also.
Of the 24 patients with idiopathic cardiomyopathy ventricular
had
OF MITRAL ANULlJS-
but for only a
(cm) and Heart Weights -__
(g) of Patients
with and without
Patients without M R
Mitral
Regurgitation
Patients with M R ?MR
Dimensions Mitral
anulus
circ
Normal Hearts
Pure AR
(24)
(10)
7-11
11-13
Marfan
FLOPPY (7)
(6)
;Ml,
Rheumatic
Ruptured Chordae
(15)
(6)
F~OPPV (6)
Marfan (4)
7-13
9-13
10-14
9-13
8-13
13-18
14-17
(11) 12-17
(12) 9-12
(11) 9-14
(11) 12-18
(11) 11-14
(10) 9-16
(15) 13-18
(16) 15-18
LV circ,
base
(9)* 10-12
LV circ,
mid
(11) 9-10
(14) 14-17
(12) 9-10
(12) 12-14
(14) 14-22
(13) 12-15
(12) 1 l-13
(15) 11-16
(17) 13-20
(10) 6-10
(15) 9-14
(11) 7-9
(9) 10-11
(16) 9-13
(14) 8-10
(13) 9-10
(13) 7-9
(16) E-11
LV length Heart
weight
(g)
(7) 250-350
(12) 680-1,250
(300)
(930)
(8) 300-650
(11) 520-920
(10) 440-830
(9) 360-675
(9) 400-650
(8) 370-880
(505)
(645)
(600)
(500)
(550)
(575)
NOTE: AR = aortic regurgitation; circ = circumference; Floppy = floppy myopathy of the ventricular dilated type; LV = left ventricle; MR = mitral * Figures in parentheses in body of table represent the average.
TABLE
III
Per Cent Changes in Mean Left Ventricular
Dimensions
mitral valve regurgation.
leaflets;
(10) 750-850 (800)
CM = idiopathic
cardro-
and Heart Weights with Dilatation
Patients without MR
Patients with M R +MR
Normal Hearts
Pure
Rheumatic
Ruptured Chordae
(“27)
(15)
(6)
Floppy (6)
Marfan
FLOPPY (7)
Marfan
Dimension
(24)
Mitral anulus (% t >9 cm)
0
22
28
22
22
22
11
66
77
LV circ, base (% 1 >ll cm)
0
27
9
9
27
18
9
36
54
LV circ. mid (% T > 10 cm)
0
50
0
10
60
40
30
30
60
LV length (%T ‘7)
0
64
14
36
43
21
29
14
43
Heart (%
0
210
68
115
100
66
83
92
166
weight
K)
(6)
t 300 g)
(4)
~______
NOTE: AR = aortic regurgitation ; circ = circumference; type; LV = left ventricle; MR = mitral regurgitation.
CM = idiopathic
October
1975
cardiomyopathy
The American
Journal
of the ventricular
of Medicine
Volume 59
dilated
459
DILATATION OF MITRAL ANULUS-BUCKLEY, ROBERTS
Figure 2. Heart of a 54 year old man (A66300) with severe sot-tic regurgitation associated with ankylosing spondyitis. a, longitudinal view exposing left atrium (LA), mitral valve (MV), left ventricle (L V) and aortic valve (A V). The dilatation is primarily in length rather than in width. b, opened mitral valve; the leaflets and its chordae are normal and the anulus is only mildly dilated.
few months in the patients with ruptured chordae tendineae. RESULTS The mean circumferences of the mitral anuli in all 78 patients with dilated left ventricles were increased: in the 23 patients without mitral regurgitation, in the 24 patients with cardiomyopathy with or without mitral regurgitation and in the 21 patients with mitral regurgitation secondary to rheumatic or ruptured chordal origin the mean mitral anular circumferences ranged from 10 to 12 cm or from 11 to 28 per cent above the normal mean mitral anular circumference of 9 cm (Tables II and Ill). In the 10 patients with mitral re-
gurgitation secondary to floppy mitral valves (unassociated with the Marfan syndrome in six and with the Marfan syndrome in four), however, the circumferences of the mitral anuli were greatly dilated, averaging 15 and 16 cm, respectively, each more than 65 per cent above the normal circumference of 9 cm. The differences between the anuli less than 30 per cent dilated and those more than 65 per cent dilated, and the differences between the normal and dilated mitral anuli are significant (p
Dilatation of the Mitral Anulus A Rare Cause of Mitral Regurgitation
BERNADINE H. BULKLEY, M.D.* WILLIAM C. ROBERTS, M.D. Baltimore, Matyland
From the Section of Pathology, National Heart & Lung institute, Natlonal Institutes of Health, Bethesda.Maryland 20014. Requests for reprints should be addressed to Dr. William C. Roberts, Ma. 10A. Rm. 3E30. National Institutes of He&h, Bethesda, Marykd 20014. Manuscript accepted January 22, 1975. * Present address: Department of Medicine, Division of Cardiology, The Johns Hopkins Hospital. Baltimore, Maryland.
To confirm or deny the thesis that mitral anular dllatatlon Is a cause of mitral regurgttatlon, this anulus was measured In 102 patients, 24 of whom had normal hearts and 78 of whom had dllated lefl ventricles, some associated with mitral regurgitation, others not. The circumference of the mitral anulus in the 24 patients with normal hearts averaged 9 cm (range 7 to 11 cm); In 24 patients with idiopathic card&myopathy of the ventricular dilated type, both wlth (12 patients) and without (12 patlents) mild to moderate regurgitation, 11 cm (range 10 to 14 cm); and in 31 patients with severe mttral regurgitation, 12 cm (range 8 to 18 cm). Among the latter 31 patients with severe m&al regurgltation, the anuius was only mlklly dilated in the 15 wlth rheumatic disease (average 11 cm) and in the SIX with ruptured chordae tendineae on prevloudy normal valves (average 10 cm); in contrast, In the 10 patients wlth floppy mitral valves with or without the Marfan syndrome the mitral anulus was greatly dilated (average 15.5 cm). Thus, only In patients with floppy valves wlth or without the Marfan syndrome or both does anular dtlatation by ltself appear great enough to cause mitral regurgttatlon. It appears, therefore, that dilatation of the mitral anulus Is a rare cause of mitral regurghatlon and that abnormality of the fibrous sketeton of the heart Is necessary for the mitral anulus to dilate enough to cause mitral regurgitation. Although believed for many years to be an important cause of mitral regurgitation, anular dilatation today is considered an infrequent cause. Surprisingly, supportive anatomic evidence for or against this view is lacking. To reexamine this concept, the mitral anulus and other left ventricular dimensions were measured in 102 human hearts, including some with and some without mitral regurgitation. METHODS
AND
DESCRIPTION
From among approximately
2,500
ditions on file in the Pathology
&
PATIENTS
STUDfED
hearts with various cardiovascular
Laboratory
of the National
con-
Heart and Lung
Institute, 78 recently accessioned hearts (all in patients greater than 14 years of age) with dilated left ventricles were selected for study. Only well
October 1975
The Amerkan Journal ol Medklne
Vohnne 59
457
DILATATION OF MITRAL ANULUS-BULKLEY,
ROBERTS
preserved hearts in which few histologic sections had been taken, or extraneous cuts made, were utilized. The measurements in each of the 102 hearts were performed separately by each of us. In addition to measuring the circumferences of the mitral anuli, several other left ventricular dimensions were measured (Figure 1): left ventricular length; the distance from the base of right anterior aortic valve cusp to the apex or the distance from the anulus behind the posterior mitral leaflet to the apex; and left ventricular circumference interiorly, at its base and midway between its base and apex. The 24 patients with normal hearts ranged in age from 19 to 69 years (average 43 years), and the 78 patients with abnormal hearts, from 15 to 78 years (average 41 years) (Table I). The latter 78 patients were divided into three major groups depending on the presence or ab-
sence of mitral regurgitation (Tables II and Ill): 23 patients without mitral regurgitation; 24 patients with idiopathic cardiomyopathy of the ventricular dilated type [I] who may or may not have had mitral regurgitation: and 31 patients with mitral regurgitation of varying etiology. Cardiac catheterization, including measurement of left ventricular pressures, and left ventricular angiographic studies were performed in 48 of the 78 patients: in 16 of 23 without mitral regurgitation, in three of 24 with cardiomyopathy and in 29 of 31 with mitral regurgitation. None of the 78 patients had stenotic valvular lesions. Aortic regurgitation was present in 14 of the 23 patients without mitral regurgitation, in none of the 24 with cardiomyopathy and in three of the 21 with mitral regurgitation (Table I). Of the 23 patients without mitral regurgitation, 10 had pure aortic regurgitation of non-Marfan etiology [2] (Figure 2), seven had floppy mitral valves (all incidental necropsy findings because none had had precordial murmurs) [2],
Figure 1. Left ventricular dimensions. The upper left diagram is a longitudinal view of the left ventricle, and the specimen itself is shown in the lower left. The upper right diagram is a view of left ventricle (L V) at its base, and the specimen itself after removal of the atria and right ventricle is shown in the lower right. The anterior mitral leaflet (A) divides the left ventricular cavify into inflow and outflow tracts. Measurements were made of the circumferences of the mitral anulus (b to c [upper left]; b to b via c [upper right]). The LV base (a to c through b [upper left]; a back to a via b, c and b [upper right]); the ma-portion of the LV id to e luooer left]) and the‘length’of’LV from base to apex (a to f via d or c to f via e [upper
left]). 458
October 1075
The Amerkan Journal of Medklne
Vdunw 59
DILATATION
and six had the Marfan aortic regurgitation
syndrome
[2],
five of whom
murmurs three
dilated type (Figure strongly suggestive
of them
the mitral
left ventricular described The
angiography.
patients
chordae
fan syndrome tion was
mitral
regurgitation
regurgitation
(Figure
secondary
with rheumatic,
II
Studied
Patients Studied
included secondary
mitral
over many years
Left Ventricular
to
valves to flop-
mitral regurgitaassociated
[2]. Mitral regurgitation
floppy and Marfan
15
with the Mar-
leaflets
appears
Dimensions
Range
24 19-69 78 15-78 10 39-56 7 18-67 6 21-48 24 21-66 15 16-40 6 20-62 6 41-78 4 15-31 ___.
43 41 47 54 36 45 25 44 54 24
11 48 9 3 5 17 3 2 5 4
13 30
0 17 10 0 4 0 0 0 0 3
1 4 1 7 12 4 1 0
.._______~ ~.~..~~~..
0 43 0 0 0 12 15 6 6 4
~_
NOTE: AR = aortic regurgitation; floppy = floppy mitral valves; CM = cardiomyopathy; CT = chordae tendineae; MR = mitral regurgitation.
in the 25 patients
etiologies,
No.
Normal hearts Abnormal hearts Pure AR Floppy Marfan CM Rheumatic Ruptured CT Floppy Marfan __~~~~_____
etiology (Fig-
was secondary
5) and four whose
syndrome
Fe- No. No. Aver- Male male with with age (no.) (no.) AR MR
by
was not
normal
unassociated
to floppy
to have been present
was
on previously
mitral leaflets
with the Marfan
Data on Patients Ages (yr)
and in
confirmed
murmur
was of rheumatic
[ 31, six whose mitral regurgitation
TABLE
was
A precordiat
tendineae
py or prolapsing
Clinical
of the
of mitral regurgitation,
with mitral
six whose
ruptured
I
12 had had precordial
regurgitation
mitral regurgitation
ure 4)
3)
in any of the other 12 patients.
31
whose
TABLE
BULKI EY. ROBERTS
also.
Of the 24 patients with idiopathic cardiomyopathy ventricular
had
OF MITRAL ANULlJS-
but for only a
(cm) and Heart Weights -__
(g) of Patients
with and without
Patients without M R
Mitral
Regurgitation
Patients with M R ?MR
Dimensions Mitral
anulus
circ
Normal Hearts
Pure AR
(24)
(10)
7-11
11-13
Marfan
FLOPPY (7)
(6)
;Ml,
Rheumatic
Ruptured Chordae
(15)
(6)
F~OPPV (6)
Marfan (4)
7-13
9-13
10-14
9-13
8-13
13-18
14-17
(11) 12-17
(12) 9-12
(11) 9-14
(11) 12-18
(11) 11-14
(10) 9-16
(15) 13-18
(16) 15-18
LV circ,
base
(9)* 10-12
LV circ,
mid
(11) 9-10
(14) 14-17
(12) 9-10
(12) 12-14
(14) 14-22
(13) 12-15
(12) 1 l-13
(15) 11-16
(17) 13-20
(10) 6-10
(15) 9-14
(11) 7-9
(9) 10-11
(16) 9-13
(14) 8-10
(13) 9-10
(13) 7-9
(16) E-11
LV length Heart
weight
(g)
(7) 250-350
(12) 680-1,250
(300)
(930)
(8) 300-650
(11) 520-920
(10) 440-830
(9) 360-675
(9) 400-650
(8) 370-880
(505)
(645)
(600)
(500)
(550)
(575)
NOTE: AR = aortic regurgitation; circ = circumference; Floppy = floppy myopathy of the ventricular dilated type; LV = left ventricle; MR = mitral * Figures in parentheses in body of table represent the average.
TABLE
III
Per Cent Changes in Mean Left Ventricular
Dimensions
mitral valve regurgation.
leaflets;
(10) 750-850 (800)
CM = idiopathic
cardro-
and Heart Weights with Dilatation
Patients without MR
Patients with M R +MR
Normal Hearts
Pure
Rheumatic
Ruptured Chordae
(“27)
(15)
(6)
Floppy (6)
Marfan
FLOPPY (7)
Marfan
Dimension
(24)
Mitral anulus (% t >9 cm)
0
22
28
22
22
22
11
66
77
LV circ, base (% 1 >ll cm)
0
27
9
9
27
18
9
36
54
LV circ. mid (% T > 10 cm)
0
50
0
10
60
40
30
30
60
LV length (%T ‘7)
0
64
14
36
43
21
29
14
43
Heart (%
0
210
68
115
100
66
83
92
166
weight
K)
(6)
t 300 g)
(4)
~______
NOTE: AR = aortic regurgitation ; circ = circumference; type; LV = left ventricle; MR = mitral regurgitation.
CM = idiopathic
October
1975
cardiomyopathy
The American
Journal
of the ventricular
of Medicine
Volume 59
dilated
459
DILATATION OF MITRAL ANULUS-BUCKLEY, ROBERTS
Figure 2. Heart of a 54 year old man (A66300) with severe sot-tic regurgitation associated with ankylosing spondyitis. a, longitudinal view exposing left atrium (LA), mitral valve (MV), left ventricle (L V) and aortic valve (A V). The dilatation is primarily in length rather than in width. b, opened mitral valve; the leaflets and its chordae are normal and the anulus is only mildly dilated.
few months in the patients with ruptured chordae tendineae. RESULTS The mean circumferences of the mitral anuli in all 78 patients with dilated left ventricles were increased: in the 23 patients without mitral regurgitation, in the 24 patients with cardiomyopathy with or without mitral regurgitation and in the 21 patients with mitral regurgitation secondary to rheumatic or ruptured chordal origin the mean mitral anular circumferences ranged from 10 to 12 cm or from 11 to 28 per cent above the normal mean mitral anular circumference of 9 cm (Tables II and Ill). In the 10 patients with mitral re-
gurgitation secondary to floppy mitral valves (unassociated with the Marfan syndrome in six and with the Marfan syndrome in four), however, the circumferences of the mitral anuli were greatly dilated, averaging 15 and 16 cm, respectively, each more than 65 per cent above the normal circumference of 9 cm. The differences between the anuli less than 30 per cent dilated and those more than 65 per cent dilated, and the differences between the normal and dilated mitral anuli are significant (p
