480
CIRCULATION
2. Longhurst J, Capone RJ, Mason DT, Zelis R: Comparison of blood flow
3.
4.
5. 6. 7. 8. 9. 10.
11.
12. 13.
measured by plethysmograph and flowmeter during steady state forearm exercise. Circulation 49: 535, 1974 Lind AR, McNicol GW: Local and central circulatory responses to sustained contractions and the effect of free or restricted arterial inflow on post-exercise hyperaemia. J Physiol (Lond) 192: 575, 1967 Brodie TG, Russell AE: On the determination of the rate of blood flow through an organ. J Physiol 32: 47P, 1905 Hewlett AE, Van Zwaluwenburg JG: The rate of blood flow in the arm. Heart 1: 87, 1909 Whitney RJ: The measurement of volume changes in human limbs. J Physiol (Lond) 9: 49, 1950 Holling HE, Boland HC, Russ E: Investigation of arterial obstruction using a mercury-in-rubber strain gauge. Am Heart J 62: 194, 1961 Zelis R, Mason DT, Braunwald E: A comparison of the effects of vasodilator stimuli on peripheral resistance vessels in normal subjects and in patients with congestive heart failure. J Clin Invest 47: 960, 1968 Kerslake DM: The effect of the application of an arterial occlusion cuff to the wrist on the blood flow in the human forearm. J Physiol (Lond) 108: 451, 1949 Astrand P, Rodahl K: Textbook of Work Physiology. New York, McGraw-Hill, 1970, p 296 Zelis R, Longhurst J: The circulation in congestive heart failure. In The Peripheral Circulations, edited by Zelis R. New York, Grune and Stratton, 1975, ch 13 Zelis R, Delea CS, Coleman HN, Mason DT: Arterial sodium content in experimental congestive heart failure. Circulation 41: 213, 1970 Zelis R, Mason DT: Diminished forearm arteriolar dilator capacity produced by mineralocorticoid-induced salt retention in man. Implications concerning congestive heart failure and vascular stiffness. Circulation 41: 589, 1970
VOL 54, No 3, SEPTEMBER 1976
14. Zelis R, Lee G, Mason DT: Influence of experimental edema on metabolically determined blood flow. Circ Res 34: 482, 1974 15. Chidsey CA, Braunwald D, Morrow AG: Catecholamine excretion and cardiac stores of norepinephrine in congestive heart failure. Am J Med 39: 442, 1965 16. Perez-Gonzalez JF, Coote JH: Activity of muscle afferents and reflex circulatory responses to exercise. Am J Physiol 223: 138, 1972 17. Clement DL, Pelletier LC, Shepherd JT: Circulatory reflexes caused by contraction of skeletal muscles in the dog. (abstr) Circulation 45: 46, 1972 18. Longhurst J, Williams R, Vaughan R, Zelis R: Evidence favoring chemoreceptor activation as the etiology of reflex cardiovascular responses from skeletal muscles. (abstr) Fed Proc 33: 296, 1974 19. Nellis SH, Pope JR, Zelis R, Beech A, Crede W: The adverse effects of high dose norepinephrine on oxygen consumption during gracilis muscle static exercise. (abstr) Clin Res 23: 199A, 1975 20. Remensnyder JP, Mitchell JH, Sarnoff SJ: Functional sympathtolysis during muscular activity. Circ Res 11: 370, 1962 21. Strandell T, Shepherd JT: The effect in humans of increased sympathetic activity on the blood flow to active muscle. Acta Med Scand (Suppl) 472: 146, 1967 22. Meakins J, Long CNH: Oxygen consumption, oxygen debt and lactic acid in circulatory failure. J Clin Invest 4: 273, 1927 23. Weiss S, Ellis LB: Oxygen utilization and lactic acid production in the extremities during rest and exercise. Arch Intern Med 55: 665, 1935 24. Bruce RA, Jones JW, Strait GB: Anaerobic metabolic responses to acute maximal exercise in male athletes. Am Heart J 67: 643, 1964 25. Huckabee WE, Judson WE: The role of anaerobic metabolism in the performance of mild muscular work. I. Relationship to oxygen consumption and cardiac output, and the effect of congestive heart failure. J Clin Invest 37: 1577, 1958
Mitral Valve Area in Combined Mitral Stenosis and Regurgitation JOSEPH ASKENAZI, M.D., C. JEFFREY CARLSON, M.D., JOSEPH S. ALPERT, M.D., AND LEWIS DEXTER, M.D. SUMMARY Eight patients with mixed mitral stenosis and regurgitation underwent hemodynamic and angiographic study prior to mitral valve replacement. The stenotic orifice of the mitral valve was calculated employing the total left ventricular stroke volume by cineangiography as the numerator of the Gorlin Formula. Excellent agreement with the measured orifice of the mitral valve was obtained
using a value of 37.9 (0.85 X 44.5) for the constant in the Gorlin formula as recommended by Cohen and Gorlin. Recalculation of this constant independently by our data yielded a value that was almost identical. Regurgitant flows and orifice sizes were calculated for each patient using the same constant as for calculation of the stenotic orifices.
CALCULATION OF THE CROSS-SECTIONAL AREA of the mitral valve by the Gorlin formula' is remarkably accurate when the valve is stenotic. It has been emphasized, however, that the calculation underestimates the true size of the valve when mitral regurgitation coexists.'1 2 The use of quantitative cineangiography3-5 makes it possible to measure diastolic mitral valve flow and hence calculation of the stenotic as well as regurgitant size of the orifice.6 Despite this method having been available since 1960,3 such measurements have seldom been made and the value of the constant in the Gorlin formula has never been determined. This study was undertaken to evaluate the accuracy of calculation of the mitral valve area in patients with mixed
mitral stenosis and insufficiency utilizing quantitative cineangiography to obtain the value for flow across the mitral valve in diastole.
From the Department of Medicine, Peter Bent Brigham Hospital and Harvard Medical School, Boston, Massachusetts. Address for reprints: Joseph Askenazi, M.D., Veterans Administration Hospital, 1400 V.F.W. Parkway, West Roxbury, Massachusetts 02132. Received March 8, 1976; revision accepted March 31, 1976.
Methods
Surgically excised mitral valves were obtained in eight selected patients with mixed mitral stenosis and insufficiency (MS-MR) undergoing valve replacement. Six of the eight patients were operated on less than one week following cardiac catheterization (table 1) and in all but one patient (4), the mitral valve was obtained intact. In this patient, the mitral valve was reconstructed postoperatively. The fresh excised valves were flattened on a plate of glass which fixed them in a standard maximum diastolic position. They were then photographed from the ventricular and atrial aspects alongside a centimeter ruler placed in the plane of the valve orifice (fig. 1). The actual area of the valve orifice was measured by planimetry. The largest planed area
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
MV AREA SIZING IN REGURGITATION/Askenazi
et
al.
481
FIGURE 1. Mitral valve infteshform, photographed immediately after its removalfrom patient #5. Measured area was 1.3 cm2. A) from the atrial aspecl: B) from the ventricular aspect. was accepted as the actual valve area. In the patient in whom the mitral valve was reconstructed (4), the valve area was also measured with calipers at the time of surgery.
anterior oblique position. In each patient, the rhythm was stable throughout the cineangiographic recording. The ventricular volumes were averaged from at least three beats. Occasional extrasystolic and postextrasystolic beats were excluded. Heart rates were similar during Fick cardiac output and ventriculograms (table 1). Calibration of left ventricular volume was performed with a cm grid placed at the level of the apex of the left ventricle with the same image-to-intensifier distance as employed dur-
Hemodynamic Studies
All eight patients were considered to have satisfactory hemodynamic and angiographic studies. Pressures were measured with Statham P23d manometers and recorded with an E for M 8-channel recorder. Left atrial pressures were recorded as pulmonary capillary wedge pressures confirmed by appropriate wave form, greater than 95% saturation of withdrawn blood sample, and constancy of pressure at several sites. Mitral valve pressure gradients were of sufficient magnitude to be accurately and easily planimetered. Cardiac outputs were obtained by the Fick principle by collecting expired air for 3 min in a Douglas bag, measuring its volume in a Tissot spirometer, and measuring the pO0 with a Pauling oxygen meter. Midway during the collection of expired air, bloods were withdrawn from pulmonary and brachial arteries for determination of oxygen content. Pressures and flows were obtained simultaneously.
ing the ventriculogram.7
8
The close agreement between Fick outputs and ventriculographic outputs in patients without valvular regurgitation and with normally contractile left ventricles is seen in table 2. In 16 patients the average Fick cardiac output was 5.84 ± 1.25 L/min (+ SD), and left ventriculographic output was 5.80 ± 1.36 L/min. (r = 0.94). Calculations
The area of the stenotic orifice of the mitral valve (MVAd) calculated as follows using the hydraulic formula of Gorlin and Gorlin.1 was
Angiographic Studies
MVFd
MVAd (cm2)
The method of Dodge et al.5' I and Kennedy et al.7 ' was followed scrupulously. High quality left ventricular angiograms were obtained in each case in the 30 degree right
where =
MVFd
C
X
44.5
(ml/min)
=
x
PR X Dfp VVCWJdTVdm
flow
across
mitral valve in diastole
total left ventricular output (Ft) obtained by cineangio-
TABLE 1. Hemodynamics and Calculation of Stenotic Orifice in Patients with Mitral Stenosis - Mitral Regurgitation Fick cardiac output
Time:
5/Age/Sex
1/58/F
2/51/F
3/52/F
4/35/F
5/61/F
6/47/F
7/52/F 8/45/F Average
cath to surgery
(days)
4 3 5 2 11 2 2 30
FF
(L/min) 3.3
2.8 2.7 3.2 5.9 1.6 3.6 4.7
HR
(beats /min)
Dfp* (sec)
86 75 100 105 105 92 140 60
0.35 0.38 0.31 0.32
0.27 0.42 0.22 0.58
MVF
MDG*
(ml/see)
(mm Hg)
109 98 88 95 208 42 117 135
17 15 22 24 25 22 52 11
MVA
(cm2)
0.7 0.7 0.5 0.5 1.1
Ventriculographic cardiac output HR MVA FT (beats/ MVF (L/min) min) (ml/see) (cm')
5.4 5.9 6.4
7.5 6.8
0.3
6.7
0.4 1.1 0.7
13.7 5.7
85 78 98 102 105 92 140 60
182 199 211 230 240 173 445 164
1.2 1.4 1.2 1.2
1.3 1.0 1.6 1.3 1.3
Measured size of orifice
(cm2)
1.2 1.3
1.2 1.2 1.3 1.0
I.5 1.3 1.3
Empiric constant
of Gorlin formula -calculated C C x 44.5
0.83 0.89 0.84 0.88 0.83 0.83
0.92 0.86 0.86
*Same for Fick and ventriculographic studies. Abbreviations: FF = forward (aortic blood flow); FT = total left ventricular output; HR = heart rate; Dfp = diastolic filling period; MVF diastole; MVA = size of stenotic orifice or mitral valve; MDG = mean dliastolic gradient.
across mitral valve during
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
=
36.9 39.6 37.4 39.2
36.9 36.9 40.9 38.3 38.3 rate of flow
482
VOL 54, No 3, SEPTEMBER 1976
CIRCULATION
TABILE 2. Fick and Ventriculographic Cardiac Outputs in Patients without Valvular Regurgitation Pt
Fick
LVgram
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Mean
6.8 7.7 4.4 5.8 5.8 6.1 5.2 5.5
6.9 7.4 4.2 6.3 6.2 6.3 4.9 5.5 5.5 4.9 3.7 6.8 7.7 7.8 3.4 5.3
6.7 5.5 4.1
6.4 7.3 7.5 3.2 5.4 SD
5.84
-
1.25
5.80
-
E
cm
1.6+
0
1.44 4
1.2+ w
1.00.8-
Q.b_= e
0
r= 0.98
06
14J i
1 2 1.4 1.6 1.8 2.0 CALCULATED M.VA by ANGIO. I
0.6 0.8
1.36
l
1.0
1.2
cm2
A correlation coefficient of r = 0.94 is obtained between Fick and ventriculographic (LVgram) output, (single RAO plane) in patients without regurgitant valve. The standard error of estimate is 0.4 L/min.
FIGURE 2. Relation between measured mitral valve area (MVA) and calculated MVA in eight patients.
gram of the LV according to the method of Dodge et al;3 C = 0.85, (C X 44.5 = 37.9);9 PR = pulse rate per minute; Dfp = diastolic filling period (seconds per beat) obtained from simultaneous LV and PCW pressure tracings; PCWdm = pulmonary capillary wedge diastolic mean pressure (mm Hg) obtained by planimetry; LVdm = left ventricular diastolic mean pressure (mm Hg) obtained by planimetry. The regurgitant area of the mitral valve (MVAr) was calculated as follows:
rate, diastolic filling period and pressure gradient and solving for C in the Gorlin formula: MVFd
MVAd X 44.5 X PRX DfpX VW TVd
Regurgitant
C averaged 0.86 for the eight patients. C X 44.5 averaged 38.3 with variations from 36.9 to 40.9. The hemodynamics of mitral regurgitation are shown in table 3. The regurgitant flow varied from 1.0 to 10.1 L/min in different patients. The calculated sizes of the regurgitant orifice varied from 0.1 to 1.1 cm2 in these patients.
where FR = FT - FF (ml/min); FT = total LV output (ml/min) determined by ventriculography;5 FF = forward flow, i.e., Fick cardiac output (ml/min); C = 0.85 (assumed) = (C X 44.5 = 37.9); SEP = systolic ejection period (sec per beat) = PR (ECG) minus Dfp; LVsm = left ventricular systolic mean pressure (mm Hg) obtained by planimetry; LA,m = PCW systolic mean pressure (mm Hg) obtained by planimetry. Hemodynamic and angiographic data for diastole and the calculation of stenotic valve orifices were compared with those measured directly and are shown in table 1. When cardiac output was measured by the Fick principle, the calculated mitral valve area was consistently less than the true area (table 1). The difference was as little as 0.2 cm2 (patients 5 and 8) when regurgitation was slight or as much as 1.1 cm2 (patient 7) when regurgitation was considerably larger. In contrast, when mitral valve flow during diastole was measured by ventriculography (cineangiography), there was an excellent correlation between calculated and measured size of the valve orifice (r = 0.98) (fig. 2). In six of the eight patients, the calculated and measured valve sizes were the same. In the other two, the difference was only 0.1 cm2. The empirical constant, C, was calculated for each case by using the actual valve area, the ventricular flow, the pulse
Discussion Gorlin and Gorlin' originally used an empirical constant of 31 (0.7 X 44.5) in their formula for calculating the size of the mitral orifice. This was before the time of left heart catheterization. The LV diastolic pressure was assumed to be 5 mm Hg and the Dfp was measured from the arterial pressure tracing as the time between onset of the dicrotic notch and the upstroke. This time is longer than the Dfp obtained from LV tracings because it does include the time of isometric contraction and relaxation. Cohen and Gorlin9 recently revised the constant to 37.9 (0.85 X 44.5) when the Dfp was measured from the LV - PCW pressure tracings. The present study confirms their use of this constant. In these eight patients, the average constant, calculated from measured valve size, ventriculographic flows, and Dfp from LV - PCW pressures, was 38.3 (0.86 X 44.5), a value practically identical with that of Cohen and Gorlin. For the ventriculographic method to be acceptable for use in calculating stenotic and regurgitant orifices in the presence of combined mitral stenosis and regurgitation, the technique must be such that there is good agreement between cardiac outputs obtained by ventriculography and by Fick or dye methods in the absence of regurgitation. This was true in this study as shown in table 2. It was only by the most scrupulous attention to the method of Dodge and
(CM2) MVAr(c)=
flow (FR) C X 44.5 X PR X SEP X VEV_7MTL m
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
MV AREA SIZING IN REGURGITATION/Askenazi et al.
483
TABLE 3. Hemodynamics and Calculation of Regurgitant Orifice in Patients with Mitral Stenosis - Mitral Regurgitation FF
1 2
3 4 5 6
7 8
(L/min) 3.3 2.8 2.7 3.2
FT
FR
HR
SEP
MVFR
(L/min)
(L/min)
(beats/min)
(sec/beats)
(ml/sec)
5.4
85 78 98 102 105
0.36 0.39 0.30 0.27
67.8 104.6 124.6 153.1
APs
(mm
Hg)
(cm2)
85
0.2
0.2 0.3 0.5 0.9 0.8 1.1 0.1
5.9
7.5 6.8
2.1 3.1 3.7 4.3 0.9
0.30
28.6
127 110 73 77
1.6
6.7
5.1
92
0.23
241.0
59
3.6 4.7
13.7 5.7
10.1 1.0
140 60
0.21 0.42
343.5 39.7
65 79
5.9 6.4
MVAR
Abbreviations: Fi = forward (aortic) blood flow; FT = total left ventricular output; FR = regurgitant flow; HR heart rate; SEP = systolic ejection period; MVFR = regurgitant flow across mitral valve; APs = mean systolic gradient across the mitral valve; MVAR = regurgitant area of mitral valve.
Kassar and their associates" that such agreement could be obtained. When the size of the stenotic orifice of the mitral valve was calculated in these patients with combined stenosis and regurgitation, the Fick method yielded falsely low values for orifice size (table 1). Gorlin and Gorlin,l Selzer et al.,2 and others have pointed out this fact. The reason is that the Fick output measures the flow going to the body, back to the lungs and through the mitral valve. This is an accurate method of measure of diastolic flow across the mitral valve in the absence of regurgitation but in its presence the Fick method is not. When mitral regurgitation is present, the diastolic mitral flow will be the forward flow (Fick) and the regurgitant flow; therefore the total left ventricular output (FT) equals that which flows across the mitral valve during diastole and is used in the numerator of the Gorlin equation. The present study verifies this method, there being a remarkably close agreement between calculated and measured sizes of the stenotic orifices when the constant of Cohen and Gorlin9 is used (fig. 2). There have been few reports of the calculation of regurgitant orifice sizes and volumes of regurgitation in mitral valve disease.4 6,e10-13 Because of the high head of pressure in the LV and the relatively low pressure in the LA, it is apparent that a small orifice (0.1 cm2 in patient 8) can allow 1.0 L/min of regurgitation. The largest regurgitant orifice in our patients was 1.1 cm2 with a regurgitant flow of 10.1 L/min (patient 7) - nearly three times more than the amount flowing out to the body via the aorta. Arvidsson and Karnell'
and Sandler, Dodge, et al." measured even larger flows and orifices.
References 1. Gorlin R, Gorlin SG: Hydraulic formula for calculation of area of stenotic mitral valve, other cardiac valves and central circulatory shunts. Am Heart J 41: 1, 1951 2. Selzer A, Willett FM, McCaughey DJ, Feichtmeir TV: Uses of cardiac catheterization in acquired heart disease. N Engl J Med 257: 121, 1957 3. Dodge HJ, Sandler H, Ballew DW, Lord JD: The use of biplane angiocardiography for the measurement of left ventricular volume in man. Am Heart J 60: 762, 1960 4. Arvidsson H, Karnell J: Quantitative assessment of mitral and aortic insufficiency by angiocardiography. Acta Radiol 2: 105, 1964 5. Dodge HT: Determination of left ventricular volume and mass. Radiol Clin NA 9: 453, 1971 6. Sandler H, Dodge HT, May RE, Rackley CM: Quantitation of valvular insufficiency in man by angiocardiography. Am Heart J 65: 501, 1963 7. Kasser IS, Kennedy JW: Measurement of left ventricular volumes in man by single plane cineangiocardiography. Invest Radiol 4: 83, 1969 8. Kennedy J, Trenholme SE, Kasser IS: Left ventricular volume and mass from single-plane cineangiocardiogram. A comparison of anteroposterior and right anterior oblique methods. Am Heart J 80: 343, 1970 9. Cohen MV, Gorlin R: Modified orifice equation for mitral valve area. Am Heart J 84: 839, 1972 10. Gorlin R, Dexter L: Hydraulic formula for the calculation of the cross sectional area of the mitral valve during regurgitation. Am Heart J 43: 188, 1952 11. Richter HS: Mitral valve area: Measurement soon after catheterization. Report of a Case. Circulation 28: 451, 1963 12. Miller GAH, Kirklin JW, Swan HJC: Myocardial function and left ventricular volumes in acquired valvular insufficiency. Circulation 31: 374, 1965 13. Dexter L: Profiles in valvular heart disease. In Cardiac Catheterization and Angiography, edited by Grossman W. Philadelphia, Lea & Febiger, 1974, p 261
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
Mitral valve area in combined mitral stenosis and regurgitation. J Askenazi, C J Carlson, J S Alpert and L Dexter Circulation. 1976;54:480-483 doi: 10.1161/01.CIR.54.3.480 Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1976 American Heart Association, Inc. All rights reserved. Print ISSN: 0009-7322. Online ISSN: 1524-4539
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circ.ahajournals.org/content/54/3/480
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at: http://www.lww.com/reprints Subscriptions: Information about subscribing to Circulation is online at: http://circ.ahajournals.org//subscriptions/
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
CIRCULATION
2. Longhurst J, Capone RJ, Mason DT, Zelis R: Comparison of blood flow
3.
4.
5. 6. 7. 8. 9. 10.
11.
12. 13.
measured by plethysmograph and flowmeter during steady state forearm exercise. Circulation 49: 535, 1974 Lind AR, McNicol GW: Local and central circulatory responses to sustained contractions and the effect of free or restricted arterial inflow on post-exercise hyperaemia. J Physiol (Lond) 192: 575, 1967 Brodie TG, Russell AE: On the determination of the rate of blood flow through an organ. J Physiol 32: 47P, 1905 Hewlett AE, Van Zwaluwenburg JG: The rate of blood flow in the arm. Heart 1: 87, 1909 Whitney RJ: The measurement of volume changes in human limbs. J Physiol (Lond) 9: 49, 1950 Holling HE, Boland HC, Russ E: Investigation of arterial obstruction using a mercury-in-rubber strain gauge. Am Heart J 62: 194, 1961 Zelis R, Mason DT, Braunwald E: A comparison of the effects of vasodilator stimuli on peripheral resistance vessels in normal subjects and in patients with congestive heart failure. J Clin Invest 47: 960, 1968 Kerslake DM: The effect of the application of an arterial occlusion cuff to the wrist on the blood flow in the human forearm. J Physiol (Lond) 108: 451, 1949 Astrand P, Rodahl K: Textbook of Work Physiology. New York, McGraw-Hill, 1970, p 296 Zelis R, Longhurst J: The circulation in congestive heart failure. In The Peripheral Circulations, edited by Zelis R. New York, Grune and Stratton, 1975, ch 13 Zelis R, Delea CS, Coleman HN, Mason DT: Arterial sodium content in experimental congestive heart failure. Circulation 41: 213, 1970 Zelis R, Mason DT: Diminished forearm arteriolar dilator capacity produced by mineralocorticoid-induced salt retention in man. Implications concerning congestive heart failure and vascular stiffness. Circulation 41: 589, 1970
VOL 54, No 3, SEPTEMBER 1976
14. Zelis R, Lee G, Mason DT: Influence of experimental edema on metabolically determined blood flow. Circ Res 34: 482, 1974 15. Chidsey CA, Braunwald D, Morrow AG: Catecholamine excretion and cardiac stores of norepinephrine in congestive heart failure. Am J Med 39: 442, 1965 16. Perez-Gonzalez JF, Coote JH: Activity of muscle afferents and reflex circulatory responses to exercise. Am J Physiol 223: 138, 1972 17. Clement DL, Pelletier LC, Shepherd JT: Circulatory reflexes caused by contraction of skeletal muscles in the dog. (abstr) Circulation 45: 46, 1972 18. Longhurst J, Williams R, Vaughan R, Zelis R: Evidence favoring chemoreceptor activation as the etiology of reflex cardiovascular responses from skeletal muscles. (abstr) Fed Proc 33: 296, 1974 19. Nellis SH, Pope JR, Zelis R, Beech A, Crede W: The adverse effects of high dose norepinephrine on oxygen consumption during gracilis muscle static exercise. (abstr) Clin Res 23: 199A, 1975 20. Remensnyder JP, Mitchell JH, Sarnoff SJ: Functional sympathtolysis during muscular activity. Circ Res 11: 370, 1962 21. Strandell T, Shepherd JT: The effect in humans of increased sympathetic activity on the blood flow to active muscle. Acta Med Scand (Suppl) 472: 146, 1967 22. Meakins J, Long CNH: Oxygen consumption, oxygen debt and lactic acid in circulatory failure. J Clin Invest 4: 273, 1927 23. Weiss S, Ellis LB: Oxygen utilization and lactic acid production in the extremities during rest and exercise. Arch Intern Med 55: 665, 1935 24. Bruce RA, Jones JW, Strait GB: Anaerobic metabolic responses to acute maximal exercise in male athletes. Am Heart J 67: 643, 1964 25. Huckabee WE, Judson WE: The role of anaerobic metabolism in the performance of mild muscular work. I. Relationship to oxygen consumption and cardiac output, and the effect of congestive heart failure. J Clin Invest 37: 1577, 1958
Mitral Valve Area in Combined Mitral Stenosis and Regurgitation JOSEPH ASKENAZI, M.D., C. JEFFREY CARLSON, M.D., JOSEPH S. ALPERT, M.D., AND LEWIS DEXTER, M.D. SUMMARY Eight patients with mixed mitral stenosis and regurgitation underwent hemodynamic and angiographic study prior to mitral valve replacement. The stenotic orifice of the mitral valve was calculated employing the total left ventricular stroke volume by cineangiography as the numerator of the Gorlin Formula. Excellent agreement with the measured orifice of the mitral valve was obtained
using a value of 37.9 (0.85 X 44.5) for the constant in the Gorlin formula as recommended by Cohen and Gorlin. Recalculation of this constant independently by our data yielded a value that was almost identical. Regurgitant flows and orifice sizes were calculated for each patient using the same constant as for calculation of the stenotic orifices.
CALCULATION OF THE CROSS-SECTIONAL AREA of the mitral valve by the Gorlin formula' is remarkably accurate when the valve is stenotic. It has been emphasized, however, that the calculation underestimates the true size of the valve when mitral regurgitation coexists.'1 2 The use of quantitative cineangiography3-5 makes it possible to measure diastolic mitral valve flow and hence calculation of the stenotic as well as regurgitant size of the orifice.6 Despite this method having been available since 1960,3 such measurements have seldom been made and the value of the constant in the Gorlin formula has never been determined. This study was undertaken to evaluate the accuracy of calculation of the mitral valve area in patients with mixed
mitral stenosis and insufficiency utilizing quantitative cineangiography to obtain the value for flow across the mitral valve in diastole.
From the Department of Medicine, Peter Bent Brigham Hospital and Harvard Medical School, Boston, Massachusetts. Address for reprints: Joseph Askenazi, M.D., Veterans Administration Hospital, 1400 V.F.W. Parkway, West Roxbury, Massachusetts 02132. Received March 8, 1976; revision accepted March 31, 1976.
Methods
Surgically excised mitral valves were obtained in eight selected patients with mixed mitral stenosis and insufficiency (MS-MR) undergoing valve replacement. Six of the eight patients were operated on less than one week following cardiac catheterization (table 1) and in all but one patient (4), the mitral valve was obtained intact. In this patient, the mitral valve was reconstructed postoperatively. The fresh excised valves were flattened on a plate of glass which fixed them in a standard maximum diastolic position. They were then photographed from the ventricular and atrial aspects alongside a centimeter ruler placed in the plane of the valve orifice (fig. 1). The actual area of the valve orifice was measured by planimetry. The largest planed area
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
MV AREA SIZING IN REGURGITATION/Askenazi
et
al.
481
FIGURE 1. Mitral valve infteshform, photographed immediately after its removalfrom patient #5. Measured area was 1.3 cm2. A) from the atrial aspecl: B) from the ventricular aspect. was accepted as the actual valve area. In the patient in whom the mitral valve was reconstructed (4), the valve area was also measured with calipers at the time of surgery.
anterior oblique position. In each patient, the rhythm was stable throughout the cineangiographic recording. The ventricular volumes were averaged from at least three beats. Occasional extrasystolic and postextrasystolic beats were excluded. Heart rates were similar during Fick cardiac output and ventriculograms (table 1). Calibration of left ventricular volume was performed with a cm grid placed at the level of the apex of the left ventricle with the same image-to-intensifier distance as employed dur-
Hemodynamic Studies
All eight patients were considered to have satisfactory hemodynamic and angiographic studies. Pressures were measured with Statham P23d manometers and recorded with an E for M 8-channel recorder. Left atrial pressures were recorded as pulmonary capillary wedge pressures confirmed by appropriate wave form, greater than 95% saturation of withdrawn blood sample, and constancy of pressure at several sites. Mitral valve pressure gradients were of sufficient magnitude to be accurately and easily planimetered. Cardiac outputs were obtained by the Fick principle by collecting expired air for 3 min in a Douglas bag, measuring its volume in a Tissot spirometer, and measuring the pO0 with a Pauling oxygen meter. Midway during the collection of expired air, bloods were withdrawn from pulmonary and brachial arteries for determination of oxygen content. Pressures and flows were obtained simultaneously.
ing the ventriculogram.7
8
The close agreement between Fick outputs and ventriculographic outputs in patients without valvular regurgitation and with normally contractile left ventricles is seen in table 2. In 16 patients the average Fick cardiac output was 5.84 ± 1.25 L/min (+ SD), and left ventriculographic output was 5.80 ± 1.36 L/min. (r = 0.94). Calculations
The area of the stenotic orifice of the mitral valve (MVAd) calculated as follows using the hydraulic formula of Gorlin and Gorlin.1 was
Angiographic Studies
MVFd
MVAd (cm2)
The method of Dodge et al.5' I and Kennedy et al.7 ' was followed scrupulously. High quality left ventricular angiograms were obtained in each case in the 30 degree right
where =
MVFd
C
X
44.5
(ml/min)
=
x
PR X Dfp VVCWJdTVdm
flow
across
mitral valve in diastole
total left ventricular output (Ft) obtained by cineangio-
TABLE 1. Hemodynamics and Calculation of Stenotic Orifice in Patients with Mitral Stenosis - Mitral Regurgitation Fick cardiac output
Time:
5/Age/Sex
1/58/F
2/51/F
3/52/F
4/35/F
5/61/F
6/47/F
7/52/F 8/45/F Average
cath to surgery
(days)
4 3 5 2 11 2 2 30
FF
(L/min) 3.3
2.8 2.7 3.2 5.9 1.6 3.6 4.7
HR
(beats /min)
Dfp* (sec)
86 75 100 105 105 92 140 60
0.35 0.38 0.31 0.32
0.27 0.42 0.22 0.58
MVF
MDG*
(ml/see)
(mm Hg)
109 98 88 95 208 42 117 135
17 15 22 24 25 22 52 11
MVA
(cm2)
0.7 0.7 0.5 0.5 1.1
Ventriculographic cardiac output HR MVA FT (beats/ MVF (L/min) min) (ml/see) (cm')
5.4 5.9 6.4
7.5 6.8
0.3
6.7
0.4 1.1 0.7
13.7 5.7
85 78 98 102 105 92 140 60
182 199 211 230 240 173 445 164
1.2 1.4 1.2 1.2
1.3 1.0 1.6 1.3 1.3
Measured size of orifice
(cm2)
1.2 1.3
1.2 1.2 1.3 1.0
I.5 1.3 1.3
Empiric constant
of Gorlin formula -calculated C C x 44.5
0.83 0.89 0.84 0.88 0.83 0.83
0.92 0.86 0.86
*Same for Fick and ventriculographic studies. Abbreviations: FF = forward (aortic blood flow); FT = total left ventricular output; HR = heart rate; Dfp = diastolic filling period; MVF diastole; MVA = size of stenotic orifice or mitral valve; MDG = mean dliastolic gradient.
across mitral valve during
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
=
36.9 39.6 37.4 39.2
36.9 36.9 40.9 38.3 38.3 rate of flow
482
VOL 54, No 3, SEPTEMBER 1976
CIRCULATION
TABILE 2. Fick and Ventriculographic Cardiac Outputs in Patients without Valvular Regurgitation Pt
Fick
LVgram
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Mean
6.8 7.7 4.4 5.8 5.8 6.1 5.2 5.5
6.9 7.4 4.2 6.3 6.2 6.3 4.9 5.5 5.5 4.9 3.7 6.8 7.7 7.8 3.4 5.3
6.7 5.5 4.1
6.4 7.3 7.5 3.2 5.4 SD
5.84
-
1.25
5.80
-
E
cm
1.6+
0
1.44 4
1.2+ w
1.00.8-
Q.b_= e
0
r= 0.98
06
14J i
1 2 1.4 1.6 1.8 2.0 CALCULATED M.VA by ANGIO. I
0.6 0.8
1.36
l
1.0
1.2
cm2
A correlation coefficient of r = 0.94 is obtained between Fick and ventriculographic (LVgram) output, (single RAO plane) in patients without regurgitant valve. The standard error of estimate is 0.4 L/min.
FIGURE 2. Relation between measured mitral valve area (MVA) and calculated MVA in eight patients.
gram of the LV according to the method of Dodge et al;3 C = 0.85, (C X 44.5 = 37.9);9 PR = pulse rate per minute; Dfp = diastolic filling period (seconds per beat) obtained from simultaneous LV and PCW pressure tracings; PCWdm = pulmonary capillary wedge diastolic mean pressure (mm Hg) obtained by planimetry; LVdm = left ventricular diastolic mean pressure (mm Hg) obtained by planimetry. The regurgitant area of the mitral valve (MVAr) was calculated as follows:
rate, diastolic filling period and pressure gradient and solving for C in the Gorlin formula: MVFd
MVAd X 44.5 X PRX DfpX VW TVd
Regurgitant
C averaged 0.86 for the eight patients. C X 44.5 averaged 38.3 with variations from 36.9 to 40.9. The hemodynamics of mitral regurgitation are shown in table 3. The regurgitant flow varied from 1.0 to 10.1 L/min in different patients. The calculated sizes of the regurgitant orifice varied from 0.1 to 1.1 cm2 in these patients.
where FR = FT - FF (ml/min); FT = total LV output (ml/min) determined by ventriculography;5 FF = forward flow, i.e., Fick cardiac output (ml/min); C = 0.85 (assumed) = (C X 44.5 = 37.9); SEP = systolic ejection period (sec per beat) = PR (ECG) minus Dfp; LVsm = left ventricular systolic mean pressure (mm Hg) obtained by planimetry; LA,m = PCW systolic mean pressure (mm Hg) obtained by planimetry. Hemodynamic and angiographic data for diastole and the calculation of stenotic valve orifices were compared with those measured directly and are shown in table 1. When cardiac output was measured by the Fick principle, the calculated mitral valve area was consistently less than the true area (table 1). The difference was as little as 0.2 cm2 (patients 5 and 8) when regurgitation was slight or as much as 1.1 cm2 (patient 7) when regurgitation was considerably larger. In contrast, when mitral valve flow during diastole was measured by ventriculography (cineangiography), there was an excellent correlation between calculated and measured size of the valve orifice (r = 0.98) (fig. 2). In six of the eight patients, the calculated and measured valve sizes were the same. In the other two, the difference was only 0.1 cm2. The empirical constant, C, was calculated for each case by using the actual valve area, the ventricular flow, the pulse
Discussion Gorlin and Gorlin' originally used an empirical constant of 31 (0.7 X 44.5) in their formula for calculating the size of the mitral orifice. This was before the time of left heart catheterization. The LV diastolic pressure was assumed to be 5 mm Hg and the Dfp was measured from the arterial pressure tracing as the time between onset of the dicrotic notch and the upstroke. This time is longer than the Dfp obtained from LV tracings because it does include the time of isometric contraction and relaxation. Cohen and Gorlin9 recently revised the constant to 37.9 (0.85 X 44.5) when the Dfp was measured from the LV - PCW pressure tracings. The present study confirms their use of this constant. In these eight patients, the average constant, calculated from measured valve size, ventriculographic flows, and Dfp from LV - PCW pressures, was 38.3 (0.86 X 44.5), a value practically identical with that of Cohen and Gorlin. For the ventriculographic method to be acceptable for use in calculating stenotic and regurgitant orifices in the presence of combined mitral stenosis and regurgitation, the technique must be such that there is good agreement between cardiac outputs obtained by ventriculography and by Fick or dye methods in the absence of regurgitation. This was true in this study as shown in table 2. It was only by the most scrupulous attention to the method of Dodge and
(CM2) MVAr(c)=
flow (FR) C X 44.5 X PR X SEP X VEV_7MTL m
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
MV AREA SIZING IN REGURGITATION/Askenazi et al.
483
TABLE 3. Hemodynamics and Calculation of Regurgitant Orifice in Patients with Mitral Stenosis - Mitral Regurgitation FF
1 2
3 4 5 6
7 8
(L/min) 3.3 2.8 2.7 3.2
FT
FR
HR
SEP
MVFR
(L/min)
(L/min)
(beats/min)
(sec/beats)
(ml/sec)
5.4
85 78 98 102 105
0.36 0.39 0.30 0.27
67.8 104.6 124.6 153.1
APs
(mm
Hg)
(cm2)
85
0.2
0.2 0.3 0.5 0.9 0.8 1.1 0.1
5.9
7.5 6.8
2.1 3.1 3.7 4.3 0.9
0.30
28.6
127 110 73 77
1.6
6.7
5.1
92
0.23
241.0
59
3.6 4.7
13.7 5.7
10.1 1.0
140 60
0.21 0.42
343.5 39.7
65 79
5.9 6.4
MVAR
Abbreviations: Fi = forward (aortic) blood flow; FT = total left ventricular output; FR = regurgitant flow; HR heart rate; SEP = systolic ejection period; MVFR = regurgitant flow across mitral valve; APs = mean systolic gradient across the mitral valve; MVAR = regurgitant area of mitral valve.
Kassar and their associates" that such agreement could be obtained. When the size of the stenotic orifice of the mitral valve was calculated in these patients with combined stenosis and regurgitation, the Fick method yielded falsely low values for orifice size (table 1). Gorlin and Gorlin,l Selzer et al.,2 and others have pointed out this fact. The reason is that the Fick output measures the flow going to the body, back to the lungs and through the mitral valve. This is an accurate method of measure of diastolic flow across the mitral valve in the absence of regurgitation but in its presence the Fick method is not. When mitral regurgitation is present, the diastolic mitral flow will be the forward flow (Fick) and the regurgitant flow; therefore the total left ventricular output (FT) equals that which flows across the mitral valve during diastole and is used in the numerator of the Gorlin equation. The present study verifies this method, there being a remarkably close agreement between calculated and measured sizes of the stenotic orifices when the constant of Cohen and Gorlin9 is used (fig. 2). There have been few reports of the calculation of regurgitant orifice sizes and volumes of regurgitation in mitral valve disease.4 6,e10-13 Because of the high head of pressure in the LV and the relatively low pressure in the LA, it is apparent that a small orifice (0.1 cm2 in patient 8) can allow 1.0 L/min of regurgitation. The largest regurgitant orifice in our patients was 1.1 cm2 with a regurgitant flow of 10.1 L/min (patient 7) - nearly three times more than the amount flowing out to the body via the aorta. Arvidsson and Karnell'
and Sandler, Dodge, et al." measured even larger flows and orifices.
References 1. Gorlin R, Gorlin SG: Hydraulic formula for calculation of area of stenotic mitral valve, other cardiac valves and central circulatory shunts. Am Heart J 41: 1, 1951 2. Selzer A, Willett FM, McCaughey DJ, Feichtmeir TV: Uses of cardiac catheterization in acquired heart disease. N Engl J Med 257: 121, 1957 3. Dodge HJ, Sandler H, Ballew DW, Lord JD: The use of biplane angiocardiography for the measurement of left ventricular volume in man. Am Heart J 60: 762, 1960 4. Arvidsson H, Karnell J: Quantitative assessment of mitral and aortic insufficiency by angiocardiography. Acta Radiol 2: 105, 1964 5. Dodge HT: Determination of left ventricular volume and mass. Radiol Clin NA 9: 453, 1971 6. Sandler H, Dodge HT, May RE, Rackley CM: Quantitation of valvular insufficiency in man by angiocardiography. Am Heart J 65: 501, 1963 7. Kasser IS, Kennedy JW: Measurement of left ventricular volumes in man by single plane cineangiocardiography. Invest Radiol 4: 83, 1969 8. Kennedy J, Trenholme SE, Kasser IS: Left ventricular volume and mass from single-plane cineangiocardiogram. A comparison of anteroposterior and right anterior oblique methods. Am Heart J 80: 343, 1970 9. Cohen MV, Gorlin R: Modified orifice equation for mitral valve area. Am Heart J 84: 839, 1972 10. Gorlin R, Dexter L: Hydraulic formula for the calculation of the cross sectional area of the mitral valve during regurgitation. Am Heart J 43: 188, 1952 11. Richter HS: Mitral valve area: Measurement soon after catheterization. Report of a Case. Circulation 28: 451, 1963 12. Miller GAH, Kirklin JW, Swan HJC: Myocardial function and left ventricular volumes in acquired valvular insufficiency. Circulation 31: 374, 1965 13. Dexter L: Profiles in valvular heart disease. In Cardiac Catheterization and Angiography, edited by Grossman W. Philadelphia, Lea & Febiger, 1974, p 261
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
Mitral valve area in combined mitral stenosis and regurgitation. J Askenazi, C J Carlson, J S Alpert and L Dexter Circulation. 1976;54:480-483 doi: 10.1161/01.CIR.54.3.480 Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1976 American Heart Association, Inc. All rights reserved. Print ISSN: 0009-7322. Online ISSN: 1524-4539
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circ.ahajournals.org/content/54/3/480
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at: http://www.lww.com/reprints Subscriptions: Information about subscribing to Circulation is online at: http://circ.ahajournals.org//subscriptions/
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
