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Correlation between ultrasoundcardiography, hemodynamics and surgical findings in mitral stenosis∗
Correlation
Between Ultrasoundcardiography,
Hemodynamics
and Surgical
Mitral
Stenosis*
ARNE GUSTAFSON, Lund,
S
INCE
the
the
introduction
cardiogram value
evaluation
of
by this
of
Edler
and
method
of patients
with
in
the the
Sweden
in
METHODS
1954,’
Ultrasoundcardiogram: The equipment used was the ultrasound reflectoscope (manufactured by Siemens Reiniger Werke, Germany), described in detail by Edler.9 A barium titanate crystal with a diameter of 12 mm. and a frequency of 2.5 mc./sec. (maximal impulse intensity 40 watts/cm.2) was used. The ultrasoundcardiographic tracings were recorded with the direct-writing method described by Effert et al.1° The electrocardiograph used for the recording was a Mingograph 42 (Elema, Stockholm). The electrocardiogram and phonocardiogram were recorded simultaneously with the ultrasoundcardioThe paper speed of the Mingograph was 50 gram. mm./sec. To calibrate the ultrasoundcardiographic tracing,
preoperative valvular
dis-
ease has been established.2-5 The aim of the present investigation was to study in greater detail the correlation of the ultrasoundcardiographic findings with preoperative hemodynamic data at rest and during exercise and with the surgical findings at mitral commissurotomy. Simultaneously with this study, a statistical evaluation of the reproducibility of the ultrasoundcardiographic method has been made. The results have been briefly reported earlier6,7 and will be published in more detail elsewhere.*
a test plug, consisting of a piece of aluminum with a piezoelectric crystal attached to one end, was used.rO The time taken for an ultrasound impulse to pass from the crystal to the opposite end of the plug and back corresponds to that for an impulse to traverse 2 cm. of blood back and forth. The standardization of the electrocardiograph was adjusted so that the distance between the echoes produced by the test plug corresponded to 2 cm. on the electrocardiographic paper. This test was repeated at the end of each tracing. The recordings were made when the patient was lying down and breathing normally with the chest Whenever possible, recordings elevated about 20”. were made from both the third and the fourth costal interspaces at varying distance from the midsternal line; the latter distance was determined by the ability to get satisfactory tracings. The crystal was held as vertical as possible at the recordings; extreme inclinations were avoided. Two variables were determined in each ultrathe rate of diastolic soundcardiographic tracing: descent (descent-rate) and the maximal amplitude (Fig. 1). In each tracing the descent-rate was calculated as the mean value of measurements during 20
MATERIAL Seventy-one patients with disease of the mitral valve, judged as predominant mitral stenosis, were studied. All patients were subsequently operated on during the period May 1963 to September 1964. There were 42 women with a mean age of 46 years (range 29-61) and 29 men with a mean age of 47 years (range 30-60). Of the total patients, 39 had sinus rhythm and 32, atria1 fibrillation. In 4 patients the diagnosis was restenosis after an earlier digital mitral commissurotomy. Six patients had an apical systolic murmur which 11 patients it was pansystolic ; in an additional occupied three-fourths of systole. This murmur was considered as indicative of a certain degree of mitral insufficiency. Physical signs of concomitant aortic valvular disease were found in 19 patients. Only 1 patient had electrocardiographic signs of left ventricular hypertropy. This patient also had arterial hypertension. * From
the Department
of Cardiology
M.D
ultrasound-
Hertz
mitral
Findings in
and the Department
of Clinical
Physiology,
University
Hospital,
Lund,
Sweden.
32
THE
AMERICAN
JOURNAL
OF CARDIOLOGY
Ultrasoundcardiography,
FIG. 1. recorded
Ultrasoundcardiographic with electrocardiogram
Hemodynamics
tracing from a patient and phonocardiograms.
heart cycles, the maximal amplitude, as the mean value of 10 cycles. In each patient the mean values of descent-rate and maximal amplitude were calculated for the tracings recorded from the third and fourth costal interspaces respectively; the highest mean value for each of the variables was used for the correlation with other findings. Heart Catheterization: Right heart catheterization As a rule, a was performed in 68 of the patients. double lumen catheter was used to record the pulmonary arterial and pulmonary wedge pressures. Cardiac output was determined by the Fick and indicator-dilution methods simultaneously. Bromsulphalein was used as an indicator”; it was injected into the pulmonary artery, and arterial samples were obtained from a polyethylene catheter in the brachial artery. Pressures and flows were determined at rest and, in most patients, during exercise in the supine position on a bicycle ergometer (work load, 200-300 kp.M./ min.). Pressures and flows were determined after five minutes of work. The mitral valve area was calculated by the formula of Gorlin and Gorlinn in 44 patients who at operation had no mitral regurgitation or only the slightest degree of it. The pulmonary vascular resistance was calculated by dividing the difference (mm. Hg) between mean pulmonary arterial and wedge pressures by the cardiac output (L./min.) and expressed in arbitrary units. Surgical Technic: Closed mitral commissurotomy was performed by means of transventricular dilatation’” under controlled hypotension with Arfonad.t4 Before the induction of hypotension, the degree of regurgitation, the mobility of the leaflets, the degree VOLUME
19,
JANUARY
1967
and
Surgical
33
Findings
with mitral
stenosis,
of calcification and the size of the mitral orifice were estimated. The surgeon’s report was immediately recorded by the author on a form prepared for this study. The regurgitation, the mobility of the anterior leafet and the calc$ications were estimated as in Table I. To estimate the size of the mitral valve area the surgeon immediately after the operation shaped a copper wire to a figure with a size and form corresponding to the mitral orifice as it was palpated before commissurotomy. This figure was transferred to a millimeter paper; the mitral valve area could then be calculated by counting the square millimeters enclosed by the tracing. At 10 operations, two surgeons independently of each other used this method to determine the valve area, and their estimates showed a good agreement.8 RESULTS REPRODUCIBILITY
OF
THE
ULTR.ASOUNDCARDIOGRAPHIC
The
variation
METHOD
in the TABLE
Estimation
descent-rate
and
the
I
of Status of Mitral
Valve
Degree of Regurgitation
Mobility
0
No regurgitation
Immobile
None
+
Regurgitant jet palpable not more than 1 finger (terminal phalanx) from mitral orifice
Slight
Small,
locztlirrd
++
Jet palpable 2 fingers
Moderate
Larger,
localized
+++
Jet
Good
Extcnsivr, involvmg both leafiets and commissures
not more than from the orifice
palpable more from
3 fingers orifice
or
Calcification
34
Gustafson
Correlations of Some Hemodynamic Data to Descent-Rate of the Ultrasoundcardiogram and Mitral Valve Areas (calculated by Gorlin formula and estimated at operation). Patients with Sinus Rhythm and with Mitral Regurgitation of Degree 0 or + UCG Descent-Rate No_(mm./sec.)‘
-------Mitral ---Calculated--No.
r Cardiac index (L./min./M.2) Rest 23 Exercise 21 Mean pressures (mm. Hg) Pulmonary artery Rest 25 Exercise 23 Pulmonary arterial wedge Rest 25 Exercise 23
0.49* 0.25
Valve .\rea (cm.‘) Surgeon’s No.
r
23 21
0.58t 0.32
Estimate r
23 21
0.53* 0.52*
-0.59t -0.621
23 21
-0.6lt -0.65t
25 23
-0.49* -0.41
-0.62t -0.661
23 21
-0.671 -0.75f
25 23
-0.51t -0.54t
r = coefficient No. = number of observations; *p < 0.05; tjJ < 0.01; jp < 0.001.
of correlation.
maximal amplitude was studied during continuous and duplicate recordings with the crystal at the same site on the chest wall. At duplicate recordings, a coefficient of variation of about 8 per cent for descent-rate and about 6 per cent for maximal amplitude was found. The site of recording from the chest wall was found to be the most important cause of the variation of both the variables determined. This was shown by analysis of variance when duplicate recordings from different sites in the same patient were compared. In a series of patients, tracings were recorded from both the third and the fourth costal interspaces. The mean value of descent-rate was significantly higher (p < 0.001) in tracings recorded from the fourth interspace, while the difference between the mean values of maximal amplitude was not statistically significant. No correlation was found between the descentrate and the duration of diastole in patients with atria1 fibrillation. The descent-rate was not significantly influenced by the heart rate when recordings were made during rest and exercise in patients with sinus rhythm. Recordings were made during both atria1 fibrillation and sinus rhythm (after electric The mean differcardioversion) in 11 patients. ence in descent-rate between atria1 fibrillation and sinus rhythm was not statistically significant, while the maximal amplitude was probably significantly higher in sinus rhythm.
CORRELATIONS FINDINGS
OF ULTRASOUNDCARDIOGRAPHIC
AND
HEMODYNAMIC
MITRAL
VALVE
AREAS
WITH
DATA
The descent-rate of the ultrasoundcardiographic tracing, the mitral valve area calculated by the Gorlin formula and the area estimated at operation were correlated with all data obtained by right heart catheterization at rest and during exercise. The correlations were calculated separately for patients with sinus rhythm and with atria1 fibrillation. Within each rhythm the following correlations were calculated: (1) descent-rate and mitral valve area at operation with the hemodynamic parameters in all patients; (2) descent-rate, mitral valve area at operation and calculated mitral valve area with the hemodynamic parameters in patients with no mitral regurgitation or the slightest degree of it at operation (27 patients with sinus rhythm and 24 with atria1 fibrillation) ; and (3) the same correlations as in (2) in patients having a maximal amplitude of the ultrasoundcardiographic tracing exceeding 15 mm. (26 patients with sinus rhythm and 20 with Only the correlations in the atria1 fibrillation). third group of patients will be discussed here. The results will be published in detail elsewhere.* Patients with Sinus Rhythm (Table ZZ) : Cardiac index at rest (determined with bromsulphalein) showed a probably significant correlation with both descent-rate and mitral valve area at opTHE
AMERICAN
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Ultrasoundcardiography,
Hemodynamics
eration, while the correlation with the calculated mitral valve area was statistically significant. Most cardiac indexes above 3 L./min. were found in patients with descent-rates exceeding 15 IIUII. :‘sec. A probably significant negative correlation was also found between the arteriovenous oxygen dzxerence at rest and the three variables. Y’/lepulmonary arterial mean pressure at rest and during exercise showed a significant inverse relation to descent-rate and calculated mitral valve area; the relation to mitral valve area at operaIn all but tion was probably significant at rest. one of the patients with descent-rates of 15 mm./ sec. or less, the mean pressure during exercise was more than 50 mm. Hg. Ttle pulmonar?) arterial wedge pressure at rest and during exercise showed a significant inverse relation to descent-rate and mitral valve areas. 6 patients had wedge pressures At rest, within the normal range (12 mm. Hg or less) ; of these patients, 5 had descent-rates of 20 mm./ Six patients had pressures above sec. or higher. 20 rtl~n. Hg; all had descent-rates of 15 mm./ sec. or less. During exercise (Fig. 2) all but 1 patient with a descent-rate of 15 mm./sec. or less had pressures above 40 mm. Hg; pressures below 30 were found only in patients having descentTwo patients rates of 19 mm. /sec. or more. with descent-rates of 26 mm./sec. had wedge pressures between 30 and 40 mm. Hg. This discrepancy in one of the patients was due to the fact that the pressure had not reached a stable
63
P.A.W. mm.Hg
i
\
20
UCG mn-?s.
FIG. 2. Relation of pulmonary arterial wedge pressure during exercise to descent-rate of ultrasoundcardiogram in patients with sinus rhythm. The regression line is
VOLUME 19, JANUARY
1967
and Surgical
&,,, MVAcm2
(Calculated
35
Findings
1
I
I
UCG m&/0s.
FIG. 3. Relation of calculated mitral valve scent-rate in patients with sinus rhythm.
area to de-
level after 5 minutes of work; after 10 minutes of work it was 23 mm. Hg. This difference between wedge pressures at 5 and 10 minutes of work was exceptionally great in comparison to duplicate determinations in other patients.8 The pulmonary vascular resistance showed an inverse relation to descent-rate and valve areas; the relation to the valve areas was probably significant. Three patients had a resistance of more than 3 units at rest; all had descent-rates of 15 mm./sec. or less. Patients with Atria1 Fibrillation: The correlation between the hemodynamic parameters and the descent-rate and valve areas was less in the patients with atria1 fibrillation. The pulmonary arterial mean and wedge pressures at rest and during exercise showed an inverse relation to the three variables. However, the correlation between the pulmonary arterial mean pressure during exercise and the descent-rate was the only one of any statistical significance (r = -0.55,~ < 0.05). Four patients had mean pressures above 70 mm. Hg; of these, 3 had descentrates less than 15 mm./sec. Five patients with pressures below 40 mm. Hg had descent-rates exceeding 15 mm./sec. Three patients with very low descent-rates, namely, lo-11 mm./sec., also had high wedge pressures during exercise (44-60 mm. Hg).
36
Gustafson 30 MVAcm*
0
‘I
10
20
30
UCG mm/s.
Mitral valve area estimated by the surgeon FIG. 4. correlated to descent-rate in all patients of the present series. Large filled circles represent patients with maxi-
mal amplitude
RELATION
5 15 mm.
BETWEEN
CALCULATED
MITRAL
DESCENT-RATE VALVE
AND
AREA
A significant correlation was found between the descent-rate and the calculated valve area in 24 patients with sinus rhythm (r = 0.62, p < 0.01) (Fig. 3). All but one patient with a descent-rate of 15 mm./sec. or less had valve areas smaller than 1.5 cm.2; the patient with a larger area was the only one with a maximal amplitude not exceeding 15 mm. In the 23 patients with a maximal amplitude exceeding 15 mm., the correlation was statistically highly significant (r = 0.67,~ < 0.001). In 20 patients with atria1 fibrillation, the correlation between descent-rate and calculated valve area was not statistically significant (r = 0.23). Six patients with descent-rates between 10 and 14 mm./sec. had valve areas of 1 cm.2 or less. However, areas of the same size were found in 5 patients with descent-rates between 16 In 16 patients with a maximal and 20 mm./sec. amplitude exceeding 15 mm., the coefficient of correlation was 0.25 (p > 0.10). RELATION AND
BETWEEN
SURGlCAL
presumably indicating a rather immobile anterior leaflet, showed a poor correlation between descent-rate and valve area. The descent-rate was between 7 and 14 mmjsec. in all but 2 of 12 patients with an amplitude of 15 mm. or less; the valve areas ranged between 0.9 and 2.5 cm.2. The coefficient of correlation was 0.64 (p < 0.001) for the relation between descent-rate and valve area in 59 patients with a maximal amplitude exceeding 15 mm. The best correlation was found in 34 patients with sinus rhythm and a maximal amplitude of more than 15 mm. (r = 0.72, p < 0.001) (Fig. 5). Of 11 patients with a descent-rate of 15 mm./sec. or less, 8 had valve areas of 1.5 cm.2 or less. No patient with a valve area below this value had a descent-rate exceeding 15 mm./sec. In 25 patients with atria1 fibrillation and a maximal amplitude of more than 15 mm., the correlation between descent-rate and valve area was not statistically significant (r = 0.39, p = 0.1-0.05). The poor correlation was caused by 2 patients with low descent-rates,namely, 16 and Of 10 pa13 mm./sec., at areas of 2.5 cm.2. tients with rates of 15 mm./sec. or lower, only 2 had valve areas exceeding 1.5 cm.2. The inzuence of mitral regurgitation estimated by the surgeon on the correlation between descentIn 52 rate and valve area was also studied. patients with no mitral regurgitation or only the slightest degree of it, the coefficient of correlation in 19 patients with 2+ was 0.48 (/J < 0.001); and 3+ regurgitation, it was 0.64 (p < 0.001).
ULTRASOUNDCARDIOGRAM
FINDINGS
The correlation was statistically highly significant (r = 0.51, p < 0.001) between the descent-rate and the mitral valve area estimated by Figure 4 the surgeon in all the patients studied. that patients with an ultrasoundshows cardiographic tracing of low maximal amplitude,
10
20
UCG mn-%
FIG. 5. Relation of surgeon’s estimate of mitral valve area to descent-rate in patients with sinus rhythm and maximal amplitude >15 mm. THE
AMERICAN
JOURNAL
OF
CARDIOLOGY
Ultrasoundcardiography,
,,,Ampli
tude
Hemodynamics
mm.
and
.Ampli tude
Surgical
Findings
37
mm. . . . ..
25'
.. . .
20'
15.
-
. . .
10.
. . .. . . . .. ..
. .. 7
.. .. .. . . .
‘.*A*
.
‘.V :I:
1.
* ... .
7-r
%t' 2[ .. .
.
..
.
.
::: ... .. . .. . ... . I.
:
.
-
II
.. ..
.
. .
.
10
5.
. ..
5
I
I
0
(*)
(**I
(***I
(**+I
(**I
Mobility
(*I
0
Calcification
A
B
FIG. 6. =\, maximal amplitude of ultrasoundcardiographic tracing in relation to mobility of anterior mitral leaflet estimated by the surgeon. (See methods.) Horizontal lines represent mean values. B, maximal amplitude in relation to degree of calcification of mitral valve estimated by the surgeon. (See methods.) Horizontal lines represent mean values. ‘T/M calculated mitral valve area was also correlated with the valve area estimated at operation. In 24 patients with sinus rhythm, the correlation between the areas was statistically significant (r = 0.52, p < O.Ol), while it was not significant in 20 patients with atria1 fibrillation (r = 0.43, p = 0.1-0.05). RR maximal amplitude of the ultrasoundcardiographic tracing was related to the mobility of the anterior leaflet and the degree of calcification estimated by the surgeon. Figure 6A shows that the amplitude decreased with decreasing mobility of the leaflet. The amplitude was 15 mm. or less in all but 1 of the 5 patients with immobile leaflets; on the other hand, it was 20 mm. or more in 27 of the 32 patients with a good mobility of the leaflet. One of the latter patients had a maximal amplitude of 15 mm.; the same value of the excursion of the anterior leaflet was found at left ventricular angiocardiography. In the groups with slight or moderate mobility of the leaflet, the pattern of amplitude was more mixed. Figure 6B shows that the mean value of maximal amplitude decreased with increasing degree of calcification. Of 14 patients with the most extensive calcifications, 9 had a maximal amplitude of 15 lnm. or less. By analysis of variance VOLUME
19, JANUARY
1967
it was shown that the relation of the amplitude to the mobility of the anterior leaflet and to the degree of calcification was statistically significant (p < 0.001). In 52 patients with no mitral regurgitation at operation or the slightest degree of it, the mean value of maximal amplitude was 20.9 mm.; in 19 patients with regurgitation estimated as 2f and 3+, the mean value was 17.5 mm. The difference between the mean values was statistically significant. L>ISCUSSION HEMODYNAMIC
FINDINGS
The validity of the ultrasoundcardiogram in estimating the functional degree of mitral stenosis was studied in the present investigation by comparing the relation of the descent-rate to different hemodynamic parameters with that of two other estimates of the degree of stenosis, namely, the mitral valve areas calculated by the Gorlin formula and that estimated at operation. On the whole, the descent-rate and the valve areas showed the same trend and the same level of significance when correlated with the hemodynamic parameters obtained by right heart catheterization at rest and during exercise. The correlations of the three variables with the hemo-
38
Gustafson pressure
B
UCG
m
[*cm
C
w
ux
12m
3
FIG. 7. Relation of movements of anterior mitral leaflet to ultrasoundcardiographic tracing in A, normal mitral valve, B, mitral stenosis without severe valvulitis and C, mitral stenosis with severe valvulitis and calcification, (See text.)
dynamic sinus
findings
rhythm
than
were
stronger
in those
with
in patients atria1
with
fibrilla-
which presumably was due to the effect of atria1 fibrillation per se on the hemodynamics. The “myocardial factor,” with its consequences for the hemodynamics irrespective of the degree of mitral stenosis, is also likely to be of greater importance in this rhythm.15 Hemodynamic data obtained at combined right and left heart catheterization have been correlated with the calculated mitral valve area In this study the relation in several studies.*6l’7 of cardiac index and pulmonary arterial wedge pressure at rest to the descent-rate and valve areas in the patients with sinus rhythm agrees with the relation of cardiac index and left atria1 tion,
to calculated valve area in these studies.16317 In the patients with sinus rhythm, the most abnormal hemodynamics were found in those with a descent-rate of 15 mm./sec. or lower. The patients with a descent-rate of about 10 mm./sec. and a maximal amplitude exceeding 15 mm. had signs of a very tight stenosis irrespective of the heart rhythm. Effert et al.18 found a descent-rate of less than 10 mm./sec. in patients with mitral stenosis of “extreme degree.” Patients with a very slight degree of mitral stenosis were not included in the present study since an estimate of the surgical findings was the basis of selection of the material. However, patients with sinus rhythm and descent-rates within the range 20 to 27 mm./sec. generally showed signs of a less advanced stenosis even if the pressures in the pulmonary circulation were abnormal during exercise. The relation of the descent-rate to the calculated mitral valve area was statistically significant in the patients with sinus rhythm; all patients with a descent-rate of 15 mm./sec. or less and a maximal amplitude exceeding 15 mm. had valve areas smaller than 1.5 cm.2. This valve area has been considered as that giving rise to symptoms.lg Segal et a1.5 recently published a correlation of ultrasoundcardiographic findings with calculated valve area. The findings of these investigators are at variance with those of the present study. Their values of descent-rate were higher, and the scatter of the descent-rates in relation to the valve areas was greater. Thus, patients with calculated valve areas between 0.5 and 1 .O cm.2 showed rates between 10 and 40 mm./sec.; in those with valve areas between 1.0 and 1.5 cm. 2, the mean value of descent-rate was about 35 mm./sec. These findings are also at variance with those of other authors. Thus, Effert et al.‘s considered that a descent-rate of more than 35 mm./sec. represented a “functionally insignificant” stenosis. SURGICAL
FINDINGS
The descent-rate was signifiDescent-Rate: cantly related to the mitral valve area estimated by the surgeon. However, the correlation was poor in patients with an ultrasoundcardiographic tracing of low maximal amplitude, that is, 15 mm. or less. Figure 7 shows the ultrasoundcardiographic tracing in relation to the movements of the anterior mitral leaflet. (The anatomic drawings THE AMERICAN
JOURNAL
OF
CARDIOLOGY
Ultrasoundcardiography,
Hemodynamics
in Fig. 7, B and C, are drawings from left ventricular angiocardiograms of patients whose ultrasoundcardiograms are illustrated.) For the purpose of the present discussion, three types of mitral valves will be considered : 1. Xormal mitral valve (Fig. 7A) : The movements of the anterior mitral leaflet are unrestricted in both diastole and systole. In early diastole it makes a rapid dorsal movement in connection with the period of rapid filling. At systole it balloons into the left atrium. This is compatible with ultracardiographic findings of a rapid diastolic descent and a large maximal amplitude. This movement pattern of the normal mitral valve agrees with that found in an experimental angiocardiographic study.20 2. Mitral stenosis caused by commissural fusions without seuere ualvitis (Fig. 7B) : The pliable anterior leaflet bulges into the left ventricle in early diastole because the free edge is fixed to the shorter posterior leaflet by the commissural changes (constituting the mitral dome seen at Because of the small miangiocardiography “). tral valve area there is a prolonged emptying of the atrium ; the leaflet makes only a slow movement dorsalward. In systole the leaflet balloons against the atrium as in the normal subject; the maximal amplitude of the tracing is therefore within the normal range. In this type of case it may be said that the slow diastolic descent is caused mainly by the small orifice: the smaller the valve area, the slower the descent-rate. 3. Mitral stenosis with severe valvitis and calc$caThe excursions of the anterior tion (Fig. 7C): leaflet are restricted both during diastole and systole. No ballooning against the atrium occurs during ventricular systole, and the leaflet does not bulge into the left ventricular outflow tract during diastole, as described in the second type of mitral valve. This probably explains the very low maximal amplitude of the tracing. Similarly, the slow descent could be caused mainly by the restricted mobility of the anterior leaflet. In such a case the functional stenosis would be significant because the rigid leaflets cannot separate enough to allow a free passage of the atria1 blood during diastole; yet the mitral valve area estimated by the surgeon could be rather large if the fusion of the commissures is slight. Thus, a better correlation between the surgeon’s estimate of the mitral valve area and the descentrate would be expected in the former type of stenosis (2) than in the latter (3). VOLUME
19,
JANUARY
1967
and Surgical
Findings
39
This statement is illustrated by the findings in 2 male patients with functionally advanced stenosis, both 47 years of age. In the first patient the maximal amplitude of the ultrasoundcardiographic tracing was 28 mm. and the descentrate 11 mm./sec. At operation, the mobility of the anterior leaflet was almost normal, and only questionable small calcifications were found in the anterior commissure. The mitral valve area was 1 .l crn2 with an intercommissural diameter of 15 mm., which implied a good correlation to the descent-rate. In the second patient the maximal amplitude was only 13 mm. and the descent-rate 7 mm./sec. The mobility of the anterior leaflet was only slight, and gross calcification in both leaflets were found at operation. The mitral valve area was 2.1 CIII.~, and the intercommissural diameter 35 mm., which is within the normal range.22 Thus, the mitral stenosis was probably caused by stiff leaflets. Effert, in 1959,3 also found that the descentrate was not a reliable measure of the mitral stenosis when the maximal amplitude of the ultrasoundcardiographic tracing was less than 15 mm. The low amplitude was assumed to be caused by changes in the left atria1 wall, which at that time was thought to be the echo-giving structure. In one case Segal et al.” found a descent-rate slower than expected, less than 30 mm./sec., in relation to the degree of stenosis determined by hemodynamic findings. At operation, severe calcification of the anterior leaflet was found. On the other hand, these investigators5 found high descent-rates, namely, 36 and 42 mm./sec., in 2 patients with severe stenosis. This discrepancy was thought to be caused by the pliability of the anterior leaflet found at operation. This supposition is not consistent with the present findings: A good mobility of a pliable leaflet is reflected in a normal maximal amplitude, which does not preclude a low descent-rate because of slow emptying through a. small orifice as illustrated by Figure 7B. Segal et a1.5 reported higher descent-rates when a dominant mitral stenosis was associated with mitral regurgitation. In the present series, however, the correlation between descent-rate and mitral valve area was not adversely affected by a certain degree of mitral insufficiency. Maximal Amplitude: The mean value of the maximal amplitude in the present study was 20 mm., which is within the normal range.3ag The values are of the same order as those found in angiocardiographic studies of the excursions of the anterior leaflet in patients with mitral steno-
Gustafson sis.‘3.24 The amplitude of the excursions of the anterior leaflet measured by angiocardiography and ultrasoundcardiography in the same patient also shows a good agreement2” The amplitude was significantly correlated to both the mobility of the anterior leaflet and to An amplitude of 20 the degree of calcification. mm. or higher was indicative of a mobile anterior leaflet without severe calcification, while an amplitude of 15 mm. or lower most often was found in mitral valves with a restricted mobility of the anterior leaflet and severe calcification. The latter finding is consistent with the observations reported by Edler26r27 and more recently by Joyner et a1.,2s who found a low amplitude of the ultrasoundcardiographic tracing in the patients with advanced calcification of the valve. This information is of definite value in the preoperative evaluation of patients with mitral stenosis since the best results of closed mitral commissurotomy are by experience found in the patient whose anterior leaflet is pliable and has retained its mobility.2Q 3~ SUMMARY
The reproducibility of the ultrasoundcardiogram was statistically evaluated in a series of The varipatients with mitral valvular disease. ations in the descent-rate and the maximal amplitude of the ultrasoundcardiographic tracing were small at continuous and duplicate recordThe ings from the same site on the chest wall. most important cause for the variation of the two parameters was the site on the chest wall from No correlation which the recording was taken. was found between the duration of the heart cycle and the descent-rate in atria1 fibrillation, nor was the descent-rate related to the heart rate Recordings were made during in sinus rhythm. atria1 fibrillation and sinus rhythm in 11 paThe only difference of any statistical tients. significance was a slightly higher maximal amplitude during sinus rhythm. In 71 patients with predominant mitral stenosis, the relation of the ultrasoundcardiographic findings to hemodynamics and surgical findings In patients with sinus rhythm, the was studied. mean pulmonary arterial and wedge pressures at rest and during exercise showed a statistically significant inverse relation to the descent-rate. The hemodynamic data were also related to the mitral valve area calculated by the Gorlin The corformula and estimated by the surgeon. relations showed the same trend and level of significance as to the descent-rate.
The calculated mitral valve area was significantly related to the descent-rate in patients with sinus rhythm. The mitral valve area, estimated at operation by a method having good reproducibility, showed a significant relation to the descent-rate of the ultrasoundcardiographic tracing. The best correlation was found in patients with sinus In patients with an ultrasoundcardiorhythm. graphic tracing of low maximal amplitude, the correlation between descent-rate and valve area The relation between the movements was weak. of the anterior mitral leaflet and the ultrasoundcardiographic tracing in different types of mitral stenosis is discussed. The maximal amplitude was significantly related to both the mobility of the anterior leaflet and the degree of calcification of the mitral valve. Thus, the descent-rate of the ultrasoundcardiographic tracing gives an estimate of the functional and anatomic degree of mitral stenosis, especially in patients with sinus rhythm. The maximal amplitude gives an idea of the condition of the anterior mitral leaflet and can be of value in the selection of patients with mitral stenosis for open heart surgery. ACKNOWLEDGMENT The author is indebted to Drs. Olle Dahlblck and Jan Kugelberg, Department of Thoracic Surgery, who performed the operations. The skillful assistance of Nurse Madeleine Sjoberg and Mrs. Anne Marie Birke is gratefully acknowledged. REFERENCES 1. EDLER, I. and HERTZ, C. H. The use of ultrasonic reflectoscope for the continuous recording of the movements of heart walls. Ku@. Fysiogr. siillsk. i Lund fkhandl., 24: 5, 1954. 2. EDLER, I. and GUSTAFSON,A. Ultrasonic cardiogram in mitral stenosis. Acta med. scandinav., 159: 85, 1957. 3. EFFERT, S. Der derzeitige Stand der UltraschallArch. Kreislaufforsch., 30: 213, kardiographie. 1959. 4. JOYNER, C. R., REID, J. M. and BOND, J. P. Reflected ultrasound in the assessment of mitral valve disease. Circulation, 27: 503, 1963. 5. SEGAL, B. L., LIKOFF, W. and KINGSLEY, B. Echocardiography, clinical application in mitral stenosis. J.A.M.A., 195: 161, 1966. 6. GUSTAFSON, A. Ultrasoundcardiogram and hemodynamics in mitral stenosis. Paper read at the meeting of the Swedish Clinical Physiological Society, Stockholm, Nov. 1964. 7. GUSTAFSON,A. In: EDLER, I. Mitral valve function studied by the ultrasound echo method. Proceedings of the xnth International Congress of Radiology, Rome, 1965. Excerpta Med., in press. THE AMERICANJOURNAL OF CARDIOLOGY
Ultrasoundcardiography,
Hemodynamics
.\. Ultrasoundcardiography in mitral stenosis. AC&U med. scandmau., Suppl. 461, 1966. 9. ELXER, I. Ultrasoundcardiography. Acfa med. \Calldi?llZL'., Suppl. 370: 9-123, 1961. IO. EI.,FERT.S., HERTZ, C. H. and B~HME, W. Direkte Kcgistrierung des Ultraschall-Kardiogramms mit Jrm Elektrokardiographcn. .?tschr. Krrislauffors~h,, 48: 230, 1959. Il. \V.&N, .I. The use of bromsulphalein for deterlnination of the cardiac output. Scandinaa. J. Clin. e Lab. Znurst., 8 : 189, 1956. 12. GORLIN, K. and GORLIN, S. G. Hydraulic formula for calculation of the area of the stenotic mitral valve, other cardiac valves, and central circulatory shunts. Am. Heart J., 41: I, 1951. 13. LOGAN, A. and TURNER, K. Surgical treatment of mitral stenosis. Lancet, 2: 874, 1959. 14. BJ~~RK,V. O., HOLMDAHL, M. H. and L~F, B. Transventricular mitral valvotomy under controlled hypotension. J. Thor&c & Cardiouas. Surg., 41 : 236, 1961. 15. FLEMING, H. A. and WOOD, P. The myocardial factor in mitral valve disease. Brit. Heart J., 21: 117, 1959. 16. DICKENS, a., RABER, G., WOLDOW, A., LORANGE, G. C. and GOLDBERG, H. A study of mitral stenosis by combined catheterization of the left and right sides of the heart. ‘vem England J. Med., 256: 1017, 1957. 17. HUGENHOLTZ,P. G., RYAN, T. J., STEIN, S. W. and A1~~~~~~~, W. H. The spectrum of pure mitral stenosis. Am. J. Cardiol., IO: 773, 1962. 18. EE.FERT, S., BLEIPELD, W., DEUPMANN, F. J. and KARITSIOTIS, J. Diagnostic value of ultrasonic cardiography. Brit. J. Radial., 37: 920, 1964. 19. DEXTER, L., MCDONALD, L., RABINOWITZ, M., SAXTON, G. A. and HAYNES, F. W. Medical aspects of patients undergoing surgery for mitral stenosis. Circulation, 9 : 758, 1954. 20. PUFF, ;2., BARRENBERG, M. and GOERTLER, T. Kijntgenkinematographische Untersuchungen
8.
GIXTAPSON,
VOLUME 19, JANUARY 1967
21. 22.
23.
24.
25.
26.
27.
28.
29.
30.
and Surgical
Findings
4’1
tiber den Bewegungsmechanismus der Mitralklappe. Fortschr. GP~. Riillt,pstrahlm, 102 : 607, 1965. :~RVIDSSON,H. .\ngiocardiographic observations in mitral disease. Acta Radio/.. Suppl. 158, 1958. RUSTED, I. E., SCAEIFLY, C. l-1. and EDWARDS,.J. E. Studies of the mitral valve. I. I\natomic features of the normal mitral valve and associated structures. Circulution, 6: 825, 1952. KJELLUERG,S. R., NORDENSTR~M,B., KUDHE, U., BJ~RK, V. 0. and MALMSTRGM, G. Cardioangiographic studies of the mitral and aortic valves. Acta Radial.. Suppl. 204, 1961. BROLIN, I., LINDER, E. and PETERSON, H-I. Motility of the leaflets in mitral stenosis. A comparison between cinecardiographic and per-operation findings. Acta rhir. scandinau., Suppl. 356: 76, 1965. BOIJSEN,E. and GUSTAFSON,:\. The movements of the anterior mitral leaflet studied by ultrasounddardiography and angiocardiography. To be published. EDLER, I. Ultrasonics as an aid to diagnosis in cardiology. Symposium on Cardiac Diagnostics, University of St. .4ndrews, Dundee, Scotland, Sept. 1963. EDLER, I. Mitral valve function studied by the ultrasound echo method. International Conference on Diagnostic Ultrasound, University of Pittsburgh, May 1965. JOYNER, C. K., DYRDA, I., BARRETT, J. S. and REID, J. M. Preoperative determination of the functional anatomy of the mitral valve. Circulation, 32 (Suppl. 2): 120, 1965. MORROW, A. G., DU PLESSIS, L. 21. and \VILCOX B. K. Hemodynamic studies after mitral commissurotomy. Sqery, 54: 463, 1963. LITWAK, R. S., GADBOYS, H. L., BARON, M. G., LEV, R. and WALLACE, H. W. Elective open heart surgery in mitral stenosis. Am. J. Cardiol., 16: 206, 1965.
Between Ultrasoundcardiography,
Hemodynamics
and Surgical
Mitral
Stenosis*
ARNE GUSTAFSON, Lund,
S
INCE
the
the
introduction
cardiogram value
evaluation
of
by this
of
Edler
and
method
of patients
with
in
the the
Sweden
in
METHODS
1954,’
Ultrasoundcardiogram: The equipment used was the ultrasound reflectoscope (manufactured by Siemens Reiniger Werke, Germany), described in detail by Edler.9 A barium titanate crystal with a diameter of 12 mm. and a frequency of 2.5 mc./sec. (maximal impulse intensity 40 watts/cm.2) was used. The ultrasoundcardiographic tracings were recorded with the direct-writing method described by Effert et al.1° The electrocardiograph used for the recording was a Mingograph 42 (Elema, Stockholm). The electrocardiogram and phonocardiogram were recorded simultaneously with the ultrasoundcardioThe paper speed of the Mingograph was 50 gram. mm./sec. To calibrate the ultrasoundcardiographic tracing,
preoperative valvular
dis-
ease has been established.2-5 The aim of the present investigation was to study in greater detail the correlation of the ultrasoundcardiographic findings with preoperative hemodynamic data at rest and during exercise and with the surgical findings at mitral commissurotomy. Simultaneously with this study, a statistical evaluation of the reproducibility of the ultrasoundcardiographic method has been made. The results have been briefly reported earlier6,7 and will be published in more detail elsewhere.*
a test plug, consisting of a piece of aluminum with a piezoelectric crystal attached to one end, was used.rO The time taken for an ultrasound impulse to pass from the crystal to the opposite end of the plug and back corresponds to that for an impulse to traverse 2 cm. of blood back and forth. The standardization of the electrocardiograph was adjusted so that the distance between the echoes produced by the test plug corresponded to 2 cm. on the electrocardiographic paper. This test was repeated at the end of each tracing. The recordings were made when the patient was lying down and breathing normally with the chest Whenever possible, recordings elevated about 20”. were made from both the third and the fourth costal interspaces at varying distance from the midsternal line; the latter distance was determined by the ability to get satisfactory tracings. The crystal was held as vertical as possible at the recordings; extreme inclinations were avoided. Two variables were determined in each ultrathe rate of diastolic soundcardiographic tracing: descent (descent-rate) and the maximal amplitude (Fig. 1). In each tracing the descent-rate was calculated as the mean value of measurements during 20
MATERIAL Seventy-one patients with disease of the mitral valve, judged as predominant mitral stenosis, were studied. All patients were subsequently operated on during the period May 1963 to September 1964. There were 42 women with a mean age of 46 years (range 29-61) and 29 men with a mean age of 47 years (range 30-60). Of the total patients, 39 had sinus rhythm and 32, atria1 fibrillation. In 4 patients the diagnosis was restenosis after an earlier digital mitral commissurotomy. Six patients had an apical systolic murmur which 11 patients it was pansystolic ; in an additional occupied three-fourths of systole. This murmur was considered as indicative of a certain degree of mitral insufficiency. Physical signs of concomitant aortic valvular disease were found in 19 patients. Only 1 patient had electrocardiographic signs of left ventricular hypertropy. This patient also had arterial hypertension. * From
the Department
of Cardiology
M.D
ultrasound-
Hertz
mitral
Findings in
and the Department
of Clinical
Physiology,
University
Hospital,
Lund,
Sweden.
32
THE
AMERICAN
JOURNAL
OF CARDIOLOGY
Ultrasoundcardiography,
FIG. 1. recorded
Ultrasoundcardiographic with electrocardiogram
Hemodynamics
tracing from a patient and phonocardiograms.
heart cycles, the maximal amplitude, as the mean value of 10 cycles. In each patient the mean values of descent-rate and maximal amplitude were calculated for the tracings recorded from the third and fourth costal interspaces respectively; the highest mean value for each of the variables was used for the correlation with other findings. Heart Catheterization: Right heart catheterization As a rule, a was performed in 68 of the patients. double lumen catheter was used to record the pulmonary arterial and pulmonary wedge pressures. Cardiac output was determined by the Fick and indicator-dilution methods simultaneously. Bromsulphalein was used as an indicator”; it was injected into the pulmonary artery, and arterial samples were obtained from a polyethylene catheter in the brachial artery. Pressures and flows were determined at rest and, in most patients, during exercise in the supine position on a bicycle ergometer (work load, 200-300 kp.M./ min.). Pressures and flows were determined after five minutes of work. The mitral valve area was calculated by the formula of Gorlin and Gorlinn in 44 patients who at operation had no mitral regurgitation or only the slightest degree of it. The pulmonary vascular resistance was calculated by dividing the difference (mm. Hg) between mean pulmonary arterial and wedge pressures by the cardiac output (L./min.) and expressed in arbitrary units. Surgical Technic: Closed mitral commissurotomy was performed by means of transventricular dilatation’” under controlled hypotension with Arfonad.t4 Before the induction of hypotension, the degree of regurgitation, the mobility of the leaflets, the degree VOLUME
19,
JANUARY
1967
and
Surgical
33
Findings
with mitral
stenosis,
of calcification and the size of the mitral orifice were estimated. The surgeon’s report was immediately recorded by the author on a form prepared for this study. The regurgitation, the mobility of the anterior leafet and the calc$ications were estimated as in Table I. To estimate the size of the mitral valve area the surgeon immediately after the operation shaped a copper wire to a figure with a size and form corresponding to the mitral orifice as it was palpated before commissurotomy. This figure was transferred to a millimeter paper; the mitral valve area could then be calculated by counting the square millimeters enclosed by the tracing. At 10 operations, two surgeons independently of each other used this method to determine the valve area, and their estimates showed a good agreement.8 RESULTS REPRODUCIBILITY
OF
THE
ULTR.ASOUNDCARDIOGRAPHIC
The
variation
METHOD
in the TABLE
Estimation
descent-rate
and
the
I
of Status of Mitral
Valve
Degree of Regurgitation
Mobility
0
No regurgitation
Immobile
None
+
Regurgitant jet palpable not more than 1 finger (terminal phalanx) from mitral orifice
Slight
Small,
locztlirrd
++
Jet palpable 2 fingers
Moderate
Larger,
localized
+++
Jet
Good
Extcnsivr, involvmg both leafiets and commissures
not more than from the orifice
palpable more from
3 fingers orifice
or
Calcification
34
Gustafson
Correlations of Some Hemodynamic Data to Descent-Rate of the Ultrasoundcardiogram and Mitral Valve Areas (calculated by Gorlin formula and estimated at operation). Patients with Sinus Rhythm and with Mitral Regurgitation of Degree 0 or + UCG Descent-Rate No_(mm./sec.)‘
-------Mitral ---Calculated--No.
r Cardiac index (L./min./M.2) Rest 23 Exercise 21 Mean pressures (mm. Hg) Pulmonary artery Rest 25 Exercise 23 Pulmonary arterial wedge Rest 25 Exercise 23
0.49* 0.25
Valve .\rea (cm.‘) Surgeon’s No.
r
23 21
0.58t 0.32
Estimate r
23 21
0.53* 0.52*
-0.59t -0.621
23 21
-0.6lt -0.65t
25 23
-0.49* -0.41
-0.62t -0.661
23 21
-0.671 -0.75f
25 23
-0.51t -0.54t
r = coefficient No. = number of observations; *p < 0.05; tjJ < 0.01; jp < 0.001.
of correlation.
maximal amplitude was studied during continuous and duplicate recordings with the crystal at the same site on the chest wall. At duplicate recordings, a coefficient of variation of about 8 per cent for descent-rate and about 6 per cent for maximal amplitude was found. The site of recording from the chest wall was found to be the most important cause of the variation of both the variables determined. This was shown by analysis of variance when duplicate recordings from different sites in the same patient were compared. In a series of patients, tracings were recorded from both the third and the fourth costal interspaces. The mean value of descent-rate was significantly higher (p < 0.001) in tracings recorded from the fourth interspace, while the difference between the mean values of maximal amplitude was not statistically significant. No correlation was found between the descentrate and the duration of diastole in patients with atria1 fibrillation. The descent-rate was not significantly influenced by the heart rate when recordings were made during rest and exercise in patients with sinus rhythm. Recordings were made during both atria1 fibrillation and sinus rhythm (after electric The mean differcardioversion) in 11 patients. ence in descent-rate between atria1 fibrillation and sinus rhythm was not statistically significant, while the maximal amplitude was probably significantly higher in sinus rhythm.
CORRELATIONS FINDINGS
OF ULTRASOUNDCARDIOGRAPHIC
AND
HEMODYNAMIC
MITRAL
VALVE
AREAS
WITH
DATA
The descent-rate of the ultrasoundcardiographic tracing, the mitral valve area calculated by the Gorlin formula and the area estimated at operation were correlated with all data obtained by right heart catheterization at rest and during exercise. The correlations were calculated separately for patients with sinus rhythm and with atria1 fibrillation. Within each rhythm the following correlations were calculated: (1) descent-rate and mitral valve area at operation with the hemodynamic parameters in all patients; (2) descent-rate, mitral valve area at operation and calculated mitral valve area with the hemodynamic parameters in patients with no mitral regurgitation or the slightest degree of it at operation (27 patients with sinus rhythm and 24 with atria1 fibrillation) ; and (3) the same correlations as in (2) in patients having a maximal amplitude of the ultrasoundcardiographic tracing exceeding 15 mm. (26 patients with sinus rhythm and 20 with Only the correlations in the atria1 fibrillation). third group of patients will be discussed here. The results will be published in detail elsewhere.* Patients with Sinus Rhythm (Table ZZ) : Cardiac index at rest (determined with bromsulphalein) showed a probably significant correlation with both descent-rate and mitral valve area at opTHE
AMERICAN
JOURNAL
OF CARDIOLOGY
Ultrasoundcardiography,
Hemodynamics
eration, while the correlation with the calculated mitral valve area was statistically significant. Most cardiac indexes above 3 L./min. were found in patients with descent-rates exceeding 15 IIUII. :‘sec. A probably significant negative correlation was also found between the arteriovenous oxygen dzxerence at rest and the three variables. Y’/lepulmonary arterial mean pressure at rest and during exercise showed a significant inverse relation to descent-rate and calculated mitral valve area; the relation to mitral valve area at operaIn all but tion was probably significant at rest. one of the patients with descent-rates of 15 mm./ sec. or less, the mean pressure during exercise was more than 50 mm. Hg. Ttle pulmonar?) arterial wedge pressure at rest and during exercise showed a significant inverse relation to descent-rate and mitral valve areas. 6 patients had wedge pressures At rest, within the normal range (12 mm. Hg or less) ; of these patients, 5 had descent-rates of 20 mm./ Six patients had pressures above sec. or higher. 20 rtl~n. Hg; all had descent-rates of 15 mm./ sec. or less. During exercise (Fig. 2) all but 1 patient with a descent-rate of 15 mm./sec. or less had pressures above 40 mm. Hg; pressures below 30 were found only in patients having descentTwo patients rates of 19 mm. /sec. or more. with descent-rates of 26 mm./sec. had wedge pressures between 30 and 40 mm. Hg. This discrepancy in one of the patients was due to the fact that the pressure had not reached a stable
63
P.A.W. mm.Hg
i
\
20
UCG mn-?s.
FIG. 2. Relation of pulmonary arterial wedge pressure during exercise to descent-rate of ultrasoundcardiogram in patients with sinus rhythm. The regression line is
VOLUME 19, JANUARY
1967
and Surgical
&,,, MVAcm2
(Calculated
35
Findings
1
I
I
UCG m&/0s.
FIG. 3. Relation of calculated mitral valve scent-rate in patients with sinus rhythm.
area to de-
level after 5 minutes of work; after 10 minutes of work it was 23 mm. Hg. This difference between wedge pressures at 5 and 10 minutes of work was exceptionally great in comparison to duplicate determinations in other patients.8 The pulmonary vascular resistance showed an inverse relation to descent-rate and valve areas; the relation to the valve areas was probably significant. Three patients had a resistance of more than 3 units at rest; all had descent-rates of 15 mm./sec. or less. Patients with Atria1 Fibrillation: The correlation between the hemodynamic parameters and the descent-rate and valve areas was less in the patients with atria1 fibrillation. The pulmonary arterial mean and wedge pressures at rest and during exercise showed an inverse relation to the three variables. However, the correlation between the pulmonary arterial mean pressure during exercise and the descent-rate was the only one of any statistical significance (r = -0.55,~ < 0.05). Four patients had mean pressures above 70 mm. Hg; of these, 3 had descentrates less than 15 mm./sec. Five patients with pressures below 40 mm. Hg had descent-rates exceeding 15 mm./sec. Three patients with very low descent-rates, namely, lo-11 mm./sec., also had high wedge pressures during exercise (44-60 mm. Hg).
36
Gustafson 30 MVAcm*
0
‘I
10
20
30
UCG mm/s.
Mitral valve area estimated by the surgeon FIG. 4. correlated to descent-rate in all patients of the present series. Large filled circles represent patients with maxi-
mal amplitude
RELATION
5 15 mm.
BETWEEN
CALCULATED
MITRAL
DESCENT-RATE VALVE
AND
AREA
A significant correlation was found between the descent-rate and the calculated valve area in 24 patients with sinus rhythm (r = 0.62, p < 0.01) (Fig. 3). All but one patient with a descent-rate of 15 mm./sec. or less had valve areas smaller than 1.5 cm.2; the patient with a larger area was the only one with a maximal amplitude not exceeding 15 mm. In the 23 patients with a maximal amplitude exceeding 15 mm., the correlation was statistically highly significant (r = 0.67,~ < 0.001). In 20 patients with atria1 fibrillation, the correlation between descent-rate and calculated valve area was not statistically significant (r = 0.23). Six patients with descent-rates between 10 and 14 mm./sec. had valve areas of 1 cm.2 or less. However, areas of the same size were found in 5 patients with descent-rates between 16 In 16 patients with a maximal and 20 mm./sec. amplitude exceeding 15 mm., the coefficient of correlation was 0.25 (p > 0.10). RELATION AND
BETWEEN
SURGlCAL
presumably indicating a rather immobile anterior leaflet, showed a poor correlation between descent-rate and valve area. The descent-rate was between 7 and 14 mmjsec. in all but 2 of 12 patients with an amplitude of 15 mm. or less; the valve areas ranged between 0.9 and 2.5 cm.2. The coefficient of correlation was 0.64 (p < 0.001) for the relation between descent-rate and valve area in 59 patients with a maximal amplitude exceeding 15 mm. The best correlation was found in 34 patients with sinus rhythm and a maximal amplitude of more than 15 mm. (r = 0.72, p < 0.001) (Fig. 5). Of 11 patients with a descent-rate of 15 mm./sec. or less, 8 had valve areas of 1.5 cm.2 or less. No patient with a valve area below this value had a descent-rate exceeding 15 mm./sec. In 25 patients with atria1 fibrillation and a maximal amplitude of more than 15 mm., the correlation between descent-rate and valve area was not statistically significant (r = 0.39, p = 0.1-0.05). The poor correlation was caused by 2 patients with low descent-rates,namely, 16 and Of 10 pa13 mm./sec., at areas of 2.5 cm.2. tients with rates of 15 mm./sec. or lower, only 2 had valve areas exceeding 1.5 cm.2. The inzuence of mitral regurgitation estimated by the surgeon on the correlation between descentIn 52 rate and valve area was also studied. patients with no mitral regurgitation or only the slightest degree of it, the coefficient of correlation in 19 patients with 2+ was 0.48 (/J < 0.001); and 3+ regurgitation, it was 0.64 (p < 0.001).
ULTRASOUNDCARDIOGRAM
FINDINGS
The correlation was statistically highly significant (r = 0.51, p < 0.001) between the descent-rate and the mitral valve area estimated by Figure 4 the surgeon in all the patients studied. that patients with an ultrasoundshows cardiographic tracing of low maximal amplitude,
10
20
UCG mn-%
FIG. 5. Relation of surgeon’s estimate of mitral valve area to descent-rate in patients with sinus rhythm and maximal amplitude >15 mm. THE
AMERICAN
JOURNAL
OF
CARDIOLOGY
Ultrasoundcardiography,
,,,Ampli
tude
Hemodynamics
mm.
and
.Ampli tude
Surgical
Findings
37
mm. . . . ..
25'
.. . .
20'
15.
-
. . .
10.
. . .. . . . .. ..
. .. 7
.. .. .. . . .
‘.*A*
.
‘.V :I:
1.
* ... .
7-r
%t' 2[ .. .
.
..
.
.
::: ... .. . .. . ... . I.
:
.
-
II
.. ..
.
. .
.
10
5.
. ..
5
I
I
0
(*)
(**I
(***I
(**+I
(**I
Mobility
(*I
0
Calcification
A
B
FIG. 6. =\, maximal amplitude of ultrasoundcardiographic tracing in relation to mobility of anterior mitral leaflet estimated by the surgeon. (See methods.) Horizontal lines represent mean values. B, maximal amplitude in relation to degree of calcification of mitral valve estimated by the surgeon. (See methods.) Horizontal lines represent mean values. ‘T/M calculated mitral valve area was also correlated with the valve area estimated at operation. In 24 patients with sinus rhythm, the correlation between the areas was statistically significant (r = 0.52, p < O.Ol), while it was not significant in 20 patients with atria1 fibrillation (r = 0.43, p = 0.1-0.05). RR maximal amplitude of the ultrasoundcardiographic tracing was related to the mobility of the anterior leaflet and the degree of calcification estimated by the surgeon. Figure 6A shows that the amplitude decreased with decreasing mobility of the leaflet. The amplitude was 15 mm. or less in all but 1 of the 5 patients with immobile leaflets; on the other hand, it was 20 mm. or more in 27 of the 32 patients with a good mobility of the leaflet. One of the latter patients had a maximal amplitude of 15 mm.; the same value of the excursion of the anterior leaflet was found at left ventricular angiocardiography. In the groups with slight or moderate mobility of the leaflet, the pattern of amplitude was more mixed. Figure 6B shows that the mean value of maximal amplitude decreased with increasing degree of calcification. Of 14 patients with the most extensive calcifications, 9 had a maximal amplitude of 15 lnm. or less. By analysis of variance VOLUME
19, JANUARY
1967
it was shown that the relation of the amplitude to the mobility of the anterior leaflet and to the degree of calcification was statistically significant (p < 0.001). In 52 patients with no mitral regurgitation at operation or the slightest degree of it, the mean value of maximal amplitude was 20.9 mm.; in 19 patients with regurgitation estimated as 2f and 3+, the mean value was 17.5 mm. The difference between the mean values was statistically significant. L>ISCUSSION HEMODYNAMIC
FINDINGS
The validity of the ultrasoundcardiogram in estimating the functional degree of mitral stenosis was studied in the present investigation by comparing the relation of the descent-rate to different hemodynamic parameters with that of two other estimates of the degree of stenosis, namely, the mitral valve areas calculated by the Gorlin formula and that estimated at operation. On the whole, the descent-rate and the valve areas showed the same trend and the same level of significance when correlated with the hemodynamic parameters obtained by right heart catheterization at rest and during exercise. The correlations of the three variables with the hemo-
38
Gustafson pressure
B
UCG
m
[*cm
C
w
ux
12m
3
FIG. 7. Relation of movements of anterior mitral leaflet to ultrasoundcardiographic tracing in A, normal mitral valve, B, mitral stenosis without severe valvulitis and C, mitral stenosis with severe valvulitis and calcification, (See text.)
dynamic sinus
findings
rhythm
than
were
stronger
in those
with
in patients atria1
with
fibrilla-
which presumably was due to the effect of atria1 fibrillation per se on the hemodynamics. The “myocardial factor,” with its consequences for the hemodynamics irrespective of the degree of mitral stenosis, is also likely to be of greater importance in this rhythm.15 Hemodynamic data obtained at combined right and left heart catheterization have been correlated with the calculated mitral valve area In this study the relation in several studies.*6l’7 of cardiac index and pulmonary arterial wedge pressure at rest to the descent-rate and valve areas in the patients with sinus rhythm agrees with the relation of cardiac index and left atria1 tion,
to calculated valve area in these studies.16317 In the patients with sinus rhythm, the most abnormal hemodynamics were found in those with a descent-rate of 15 mm./sec. or lower. The patients with a descent-rate of about 10 mm./sec. and a maximal amplitude exceeding 15 mm. had signs of a very tight stenosis irrespective of the heart rhythm. Effert et al.18 found a descent-rate of less than 10 mm./sec. in patients with mitral stenosis of “extreme degree.” Patients with a very slight degree of mitral stenosis were not included in the present study since an estimate of the surgical findings was the basis of selection of the material. However, patients with sinus rhythm and descent-rates within the range 20 to 27 mm./sec. generally showed signs of a less advanced stenosis even if the pressures in the pulmonary circulation were abnormal during exercise. The relation of the descent-rate to the calculated mitral valve area was statistically significant in the patients with sinus rhythm; all patients with a descent-rate of 15 mm./sec. or less and a maximal amplitude exceeding 15 mm. had valve areas smaller than 1.5 cm.2. This valve area has been considered as that giving rise to symptoms.lg Segal et a1.5 recently published a correlation of ultrasoundcardiographic findings with calculated valve area. The findings of these investigators are at variance with those of the present study. Their values of descent-rate were higher, and the scatter of the descent-rates in relation to the valve areas was greater. Thus, patients with calculated valve areas between 0.5 and 1 .O cm.2 showed rates between 10 and 40 mm./sec.; in those with valve areas between 1.0 and 1.5 cm. 2, the mean value of descent-rate was about 35 mm./sec. These findings are also at variance with those of other authors. Thus, Effert et al.‘s considered that a descent-rate of more than 35 mm./sec. represented a “functionally insignificant” stenosis. SURGICAL
FINDINGS
The descent-rate was signifiDescent-Rate: cantly related to the mitral valve area estimated by the surgeon. However, the correlation was poor in patients with an ultrasoundcardiographic tracing of low maximal amplitude, that is, 15 mm. or less. Figure 7 shows the ultrasoundcardiographic tracing in relation to the movements of the anterior mitral leaflet. (The anatomic drawings THE AMERICAN
JOURNAL
OF
CARDIOLOGY
Ultrasoundcardiography,
Hemodynamics
in Fig. 7, B and C, are drawings from left ventricular angiocardiograms of patients whose ultrasoundcardiograms are illustrated.) For the purpose of the present discussion, three types of mitral valves will be considered : 1. Xormal mitral valve (Fig. 7A) : The movements of the anterior mitral leaflet are unrestricted in both diastole and systole. In early diastole it makes a rapid dorsal movement in connection with the period of rapid filling. At systole it balloons into the left atrium. This is compatible with ultracardiographic findings of a rapid diastolic descent and a large maximal amplitude. This movement pattern of the normal mitral valve agrees with that found in an experimental angiocardiographic study.20 2. Mitral stenosis caused by commissural fusions without seuere ualvitis (Fig. 7B) : The pliable anterior leaflet bulges into the left ventricle in early diastole because the free edge is fixed to the shorter posterior leaflet by the commissural changes (constituting the mitral dome seen at Because of the small miangiocardiography “). tral valve area there is a prolonged emptying of the atrium ; the leaflet makes only a slow movement dorsalward. In systole the leaflet balloons against the atrium as in the normal subject; the maximal amplitude of the tracing is therefore within the normal range. In this type of case it may be said that the slow diastolic descent is caused mainly by the small orifice: the smaller the valve area, the slower the descent-rate. 3. Mitral stenosis with severe valvitis and calc$caThe excursions of the anterior tion (Fig. 7C): leaflet are restricted both during diastole and systole. No ballooning against the atrium occurs during ventricular systole, and the leaflet does not bulge into the left ventricular outflow tract during diastole, as described in the second type of mitral valve. This probably explains the very low maximal amplitude of the tracing. Similarly, the slow descent could be caused mainly by the restricted mobility of the anterior leaflet. In such a case the functional stenosis would be significant because the rigid leaflets cannot separate enough to allow a free passage of the atria1 blood during diastole; yet the mitral valve area estimated by the surgeon could be rather large if the fusion of the commissures is slight. Thus, a better correlation between the surgeon’s estimate of the mitral valve area and the descentrate would be expected in the former type of stenosis (2) than in the latter (3). VOLUME
19,
JANUARY
1967
and Surgical
Findings
39
This statement is illustrated by the findings in 2 male patients with functionally advanced stenosis, both 47 years of age. In the first patient the maximal amplitude of the ultrasoundcardiographic tracing was 28 mm. and the descentrate 11 mm./sec. At operation, the mobility of the anterior leaflet was almost normal, and only questionable small calcifications were found in the anterior commissure. The mitral valve area was 1 .l crn2 with an intercommissural diameter of 15 mm., which implied a good correlation to the descent-rate. In the second patient the maximal amplitude was only 13 mm. and the descent-rate 7 mm./sec. The mobility of the anterior leaflet was only slight, and gross calcification in both leaflets were found at operation. The mitral valve area was 2.1 CIII.~, and the intercommissural diameter 35 mm., which is within the normal range.22 Thus, the mitral stenosis was probably caused by stiff leaflets. Effert, in 1959,3 also found that the descentrate was not a reliable measure of the mitral stenosis when the maximal amplitude of the ultrasoundcardiographic tracing was less than 15 mm. The low amplitude was assumed to be caused by changes in the left atria1 wall, which at that time was thought to be the echo-giving structure. In one case Segal et al.” found a descent-rate slower than expected, less than 30 mm./sec., in relation to the degree of stenosis determined by hemodynamic findings. At operation, severe calcification of the anterior leaflet was found. On the other hand, these investigators5 found high descent-rates, namely, 36 and 42 mm./sec., in 2 patients with severe stenosis. This discrepancy was thought to be caused by the pliability of the anterior leaflet found at operation. This supposition is not consistent with the present findings: A good mobility of a pliable leaflet is reflected in a normal maximal amplitude, which does not preclude a low descent-rate because of slow emptying through a. small orifice as illustrated by Figure 7B. Segal et a1.5 reported higher descent-rates when a dominant mitral stenosis was associated with mitral regurgitation. In the present series, however, the correlation between descent-rate and mitral valve area was not adversely affected by a certain degree of mitral insufficiency. Maximal Amplitude: The mean value of the maximal amplitude in the present study was 20 mm., which is within the normal range.3ag The values are of the same order as those found in angiocardiographic studies of the excursions of the anterior leaflet in patients with mitral steno-
Gustafson sis.‘3.24 The amplitude of the excursions of the anterior leaflet measured by angiocardiography and ultrasoundcardiography in the same patient also shows a good agreement2” The amplitude was significantly correlated to both the mobility of the anterior leaflet and to An amplitude of 20 the degree of calcification. mm. or higher was indicative of a mobile anterior leaflet without severe calcification, while an amplitude of 15 mm. or lower most often was found in mitral valves with a restricted mobility of the anterior leaflet and severe calcification. The latter finding is consistent with the observations reported by Edler26r27 and more recently by Joyner et a1.,2s who found a low amplitude of the ultrasoundcardiographic tracing in the patients with advanced calcification of the valve. This information is of definite value in the preoperative evaluation of patients with mitral stenosis since the best results of closed mitral commissurotomy are by experience found in the patient whose anterior leaflet is pliable and has retained its mobility.2Q 3~ SUMMARY
The reproducibility of the ultrasoundcardiogram was statistically evaluated in a series of The varipatients with mitral valvular disease. ations in the descent-rate and the maximal amplitude of the ultrasoundcardiographic tracing were small at continuous and duplicate recordThe ings from the same site on the chest wall. most important cause for the variation of the two parameters was the site on the chest wall from No correlation which the recording was taken. was found between the duration of the heart cycle and the descent-rate in atria1 fibrillation, nor was the descent-rate related to the heart rate Recordings were made during in sinus rhythm. atria1 fibrillation and sinus rhythm in 11 paThe only difference of any statistical tients. significance was a slightly higher maximal amplitude during sinus rhythm. In 71 patients with predominant mitral stenosis, the relation of the ultrasoundcardiographic findings to hemodynamics and surgical findings In patients with sinus rhythm, the was studied. mean pulmonary arterial and wedge pressures at rest and during exercise showed a statistically significant inverse relation to the descent-rate. The hemodynamic data were also related to the mitral valve area calculated by the Gorlin The corformula and estimated by the surgeon. relations showed the same trend and level of significance as to the descent-rate.
The calculated mitral valve area was significantly related to the descent-rate in patients with sinus rhythm. The mitral valve area, estimated at operation by a method having good reproducibility, showed a significant relation to the descent-rate of the ultrasoundcardiographic tracing. The best correlation was found in patients with sinus In patients with an ultrasoundcardiorhythm. graphic tracing of low maximal amplitude, the correlation between descent-rate and valve area The relation between the movements was weak. of the anterior mitral leaflet and the ultrasoundcardiographic tracing in different types of mitral stenosis is discussed. The maximal amplitude was significantly related to both the mobility of the anterior leaflet and the degree of calcification of the mitral valve. Thus, the descent-rate of the ultrasoundcardiographic tracing gives an estimate of the functional and anatomic degree of mitral stenosis, especially in patients with sinus rhythm. The maximal amplitude gives an idea of the condition of the anterior mitral leaflet and can be of value in the selection of patients with mitral stenosis for open heart surgery. ACKNOWLEDGMENT The author is indebted to Drs. Olle Dahlblck and Jan Kugelberg, Department of Thoracic Surgery, who performed the operations. The skillful assistance of Nurse Madeleine Sjoberg and Mrs. Anne Marie Birke is gratefully acknowledged. REFERENCES 1. EDLER, I. and HERTZ, C. H. The use of ultrasonic reflectoscope for the continuous recording of the movements of heart walls. Ku@. Fysiogr. siillsk. i Lund fkhandl., 24: 5, 1954. 2. EDLER, I. and GUSTAFSON,A. Ultrasonic cardiogram in mitral stenosis. Acta med. scandinav., 159: 85, 1957. 3. EFFERT, S. Der derzeitige Stand der UltraschallArch. Kreislaufforsch., 30: 213, kardiographie. 1959. 4. JOYNER, C. R., REID, J. M. and BOND, J. P. Reflected ultrasound in the assessment of mitral valve disease. Circulation, 27: 503, 1963. 5. SEGAL, B. L., LIKOFF, W. and KINGSLEY, B. Echocardiography, clinical application in mitral stenosis. J.A.M.A., 195: 161, 1966. 6. GUSTAFSON, A. Ultrasoundcardiogram and hemodynamics in mitral stenosis. Paper read at the meeting of the Swedish Clinical Physiological Society, Stockholm, Nov. 1964. 7. GUSTAFSON,A. In: EDLER, I. Mitral valve function studied by the ultrasound echo method. Proceedings of the xnth International Congress of Radiology, Rome, 1965. Excerpta Med., in press. THE AMERICANJOURNAL OF CARDIOLOGY
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.\. Ultrasoundcardiography in mitral stenosis. AC&U med. scandmau., Suppl. 461, 1966. 9. ELXER, I. Ultrasoundcardiography. Acfa med. \Calldi?llZL'., Suppl. 370: 9-123, 1961. IO. EI.,FERT.S., HERTZ, C. H. and B~HME, W. Direkte Kcgistrierung des Ultraschall-Kardiogramms mit Jrm Elektrokardiographcn. .?tschr. Krrislauffors~h,, 48: 230, 1959. Il. \V.&N, .I. The use of bromsulphalein for deterlnination of the cardiac output. Scandinaa. J. Clin. e Lab. Znurst., 8 : 189, 1956. 12. GORLIN, K. and GORLIN, S. G. Hydraulic formula for calculation of the area of the stenotic mitral valve, other cardiac valves, and central circulatory shunts. Am. Heart J., 41: I, 1951. 13. LOGAN, A. and TURNER, K. Surgical treatment of mitral stenosis. Lancet, 2: 874, 1959. 14. BJ~~RK,V. O., HOLMDAHL, M. H. and L~F, B. Transventricular mitral valvotomy under controlled hypotension. J. Thor&c & Cardiouas. Surg., 41 : 236, 1961. 15. FLEMING, H. A. and WOOD, P. The myocardial factor in mitral valve disease. Brit. Heart J., 21: 117, 1959. 16. DICKENS, a., RABER, G., WOLDOW, A., LORANGE, G. C. and GOLDBERG, H. A study of mitral stenosis by combined catheterization of the left and right sides of the heart. ‘vem England J. Med., 256: 1017, 1957. 17. HUGENHOLTZ,P. G., RYAN, T. J., STEIN, S. W. and A1~~~~~~~, W. H. The spectrum of pure mitral stenosis. Am. J. Cardiol., IO: 773, 1962. 18. EE.FERT, S., BLEIPELD, W., DEUPMANN, F. J. and KARITSIOTIS, J. Diagnostic value of ultrasonic cardiography. Brit. J. Radial., 37: 920, 1964. 19. DEXTER, L., MCDONALD, L., RABINOWITZ, M., SAXTON, G. A. and HAYNES, F. W. Medical aspects of patients undergoing surgery for mitral stenosis. Circulation, 9 : 758, 1954. 20. PUFF, ;2., BARRENBERG, M. and GOERTLER, T. Kijntgenkinematographische Untersuchungen
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