The diagnosis of valvular regurgitation (R) is usually based on clinical signs. Quantification conventionally requires catheterization (C). We have quantified R with cardiac blood pool scintigraphy (CBPS) and compared the results with those obtained by C. Regurgitant fraction (RF) determined by C was calculated with the technique of Dodge. Forward output was measured by thermodilution or cardiogreen dilution. The RF at CBPS was obtained by the stroke index ratio (SIR) minus 1.2 divided by SIR, where SIR is the ratio of the stroke counts of left venticle over those of the right ventricle. Stroke counts are calculated directly from the time-activity curves. Each time-activity curve was obtained by drawing one region of interest around each diastolic image. The correction factor (1.2) was calculated from a large normal population. 22 patients had aortic R, 7 mitral R, 12 both, 8 patients had no evidence of regurgitation. RF of the patients with R varied from 27 to 71% (x = 42%) at C and from 26 to 74% (Y = 41%) at CBPS. Linear regression shows a good correlation coefficient (r = 0.82). The regression equation is y = 0.93x + 1.8. No correlation was found between RF (CBPS or C) and the severity of R assessed visually from angiography. In conclusion: CBPS, a non-invasive method, allows easy and repeatable determination of RF and correlates well with data obtained at catheterizatio

Barthelemy, J-C

Chevigne, M.

De Bruyne, B.

Marchandise, B.

Melchior, J-P

Righetti, A.

Salembier, J-P

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European Heart Journal (1987) 8 {Supplement C), 71-75Quantification of valvular regurgitation by cardiacblood pool scintigraphy: correlation with catheterizationJ-P. MELCHIOR*t, M. CHEVIGNE*, A. RlGHETTlt, B. DE BRUYNE*, J-P. SALEMBIER*, J-C. BARTHELEMYt,B. MARCHANDISE** Cardiology Department, University of Louvain, Mont-Godinne, Yvoir, Belgium and t Cardiology Center,University Hospital, Geneva, SwitzerlandKEY WORDS: Valvular regurgitation, regurgitant fraction, cardiac catheterization, radionuclide ventriculo-graphy.The diagnosis of valvular regurgitation (R) is usually based on clinical signs. Quantification conventionallyrequires catheterization (C). We have quantified R with cardiac blood pool scintigraphy (CBPS) and comparedthe results with those obtained by C. Regurgitant fraction (RF) determined by C was calculated with thetechnique of Dodge. Forward output was measured by thermodilution or cardiogreen dilution. The RF atCBPS was obtained by the stroke index ratio (SIR) minus 1-2 divided by SIR, where SIR is the ratio of thestroke counts of left venticle over those of the right ventricle. Stroke counts are calculated directly from the time-activity curves. Each time—activity curve was obtained by drawing one region of interest around each diastolicimage. The correction factor (1-2) was calculated from a large normal population. 22 patients had aortic R, 7mitral R, 12 both, 8 patients had no evidence of regurgitation. RF of the patients with R varied from 27 to 71%(x = 42%) at C and from 26 to 74% (y = 41%) at CBPS. Linear regression shows a good correlation coefficient(r = 0-82). The regression equation is y = 0-93x + 1-8. No correlation was found between RF (CBPS or C)and the severity of R assessed visually from angiography. In conclusion: CBPS, a non-invasive method,allows easy and repeatable determination of RF and correlates well with data obtained at catheterization.Introduction MethodsThe diagnosis of aortic or mitral valve regurgita-PATIENTStion is usually based on clinical signs. The severity of . . . . . , . , . .. . ., .. . - I I j i_ Ninety-one patients who underwent left and rightvalvular regurgitation is conventionally assessed by •_ • • • _• j r J . , - 1, . ... . • i • • n 2i cathetenzation were considered for our study, 42 wereangiography: semiquantitative visual evaluation'1"-^ . , , , , . , - . . . „ • J • x.... ,. , , . , . r . . . , excluded because of: atnal fibrillation during the pro-or quantitation by combined left ventnculography . , , . , ., r , , , . • • [31 i • r cedure (3), premature beats during left ventncu-and forward output determination1-". It is often , . / , , • > • •. • - , , - • ,JTC i. . A A .u i • r • lography (11), tncuspid regurgitation (clinical and/ordifficult to decide on the optimal time of operative _ ^ , ' . ' w_1' ? , ,, , . . Doppler evidence) (5), regional motion abnormalitiesrepair and repeated invasive procedures are some- . . , .. . . ' . .._. , , . . .,41 (old myocardia infarct) (10) and non-reproducib etimes necessary1*1. , •'. . ,. ' v ; , , , Ki m-m r.- M5i- J J • values of the cardiac output (13).In 1979, Rigo et alP' introduced a new quantita- _, . . " , , ', . • r . . . r . . . . The remaining 49 patients (18 females, 31 males,tive technique for evaluation of regurgitation using , . .A- ui A i • .• u , r n n m r-nn<- • mean age 54 years: range 21-74) were evaluated bycardiac blood poo scintigraphy (CBPS). CBPS is a , ,„_„ . . • „ . , , . . • ,r . ui u J r i CBPS within 48 h of catheterization without anysafe, non-invasive, repeatable method of evaluating . . . , _, • . i.. „ , , • i r • TT. • intervening change of therapy. They comprised 8left and right ventricular function. The regurgitant , 6 . 6 . , ," • .r . . I I . r L. r i _ i control patients with no clinical or angiographicfraction is calculated from the ratio of the stroke . y . . . , , , . . f , ,.r , . . evidence of regurgitation and 41 patients with a eftcounts of the two ventricles. . . , „ . „ , , „ , ,-it. • «• i_ J • • • i regurgitation: 22 aortic, 7 mitra and 12 both.The aim of the present study is to investigate valv- 6 6ular regurgitation using the CBPS technique and to? , • . . I _ J - i CATHETERIZATIONcompare the results with those obtained invasively _ . , . . , . , , , „ . ^ ,«rby classical catheterization. ™ e anffograph.c method included RAO 30-J (37 patients) or biplane (RAO 30G-LAO 60°) (12. patients) left ventnculography with a pig-tail catheterAddress far correspondence: J-P. Mdchior, Service de Cardiologtt, . . . . . . .Clinique Ste Elizabeth, Avenue Defre, 206, B-1180 Bruxdles, i n m l l d inspiration using a power injection of 40-50Belgium. ml contrast at 12-15 ml s~'. A grid or a 6 mm ball0I95-668X/87/08C071 +05 $02.00/0 © 1987 The European Society of Cardiology72 J-P. Mekhior el at.filmed at the level of the patient's heart was used tocorrect for X-ray magnification. The end-diastolicendocardial contour was traced using the frame atthe onset of QRS. The end-systolic contour wasdrawn from the frame at which the left ventricularvolume reached a minimum by visual evaluation.Sequential numbers were allocated to each frame, sothat the same cardiac cycle and simultaneous frameswere selected for biplane analysis. Angiographicstroke volume was calculated with the method ofSandier el al.l3] using the correction factor of Ken-nedy el a/.161 only for the simple plane ventncu-lographies. Forward output was determined using oneof two dilution techniques: either iced saline with aSwan-Ganz catheter in the main pulmonary artery,or cardiogreen with the dye injected in the pul-monary artery and collected in the proximal descend-ing aorta. Thermodilution curves (46 patients) wereobtained in triplicate before angio and a mean valuewas derived, and a fourth curve was obtained sim-ultaneously with the contrast injection. Cardiogreen(16 patients) was injected twice just before angio-graphy. Thirteen patients were excluded because ofthe difference between the cardiac output values(greater than 10% difference). In order to calculatethe regurgitant fraction, we used the forward outputvalue obtained by thermodilution during ventriculo-graphy or the mean value of the two results calcu-lated from the cardiogreen dilution curvesThe regurgitant fraction was calculated as:RF% =Angiographic output — Forward outputAngiographic outputCARDIAC BLOOD POOL SCINTIGRAPHYRed cells labelling was performed by an in vivotechnique with preinjection of stannous fluoridefollowed 20 min later by 25 mCi of technetium per-technetate. An initial delay of 15 min after injectionwas respected before the first scintigraphic measure-ment, to allow for equilibrium of tracer in the bloodpool.The camera was positioned at a 35—45° LAO anglewith a 0-10° craniocaudal obliquity. The chosenincidence was the one allowing the best visual separ-ation of the four cardiac chambers. The R wave ofthe electrocardiogram was used as the synchronizingsignal and the R-R interval was divided in 16 imagesusing a 64 x 64 matrix.Left and right ventricular regions of interest weretraced on simultaneous displayed images of diastole.and systole and on phase and amplitude Founerimages. Both time-activity curves were directlyobtained from those two diastolic regions of interest.Stroke counts were calculated on the time-activitycurves substracting from the maximum, those countsobtained at the nadir of the curve No backgroundactivity substraction was done. The stroke index ratio(SIR) was defined as the ratio of the left strokecounts over the right stroke counts. Ideal ratio shouldbe 10 but our experience and data from the litera-l u r e i5 .7 -101 n a c | s n o w n l n a t j t v a r l e s f rom o-8 t o 1-7in a normal population, with a mean value of I 2.We chose I -2 as a correction factor for the calculationof the regurgitant fraction:RF(%) =SIR100The calculation of a left side regurgitation is ob-viously made only in the absence of right sideregurgitation. A valvular regurgitation was definedas significant in the presence of a regurgitant fractiongreater than 20% ( = SIR of 1-5).ResultsThe regurgitant fraction values calculated atcatheterization and by CBPS were compared inpatients with and without regurgitation (Table I).Patients without any left side regurgitation showeda calculated regurgitant fraction ranging from 9 to24% (mean 19-5%) by catheterization and from 0 to30% (mean 16%) by CBPS. Seven of the 8 patientshad a regurgitant fraction equal or less than 20% byCBPS.Patients with left side regurgitation had a regurgi-tant fraction ranging from 27% to 71% (mean 41%)by catheterization and from 26% to 74% (mean 42%)by CBPS. All 41 patients with regurgitation hada regurgitant fraction greater than 20% by CBPS.Figure I depicts the correlation between thevalues obtained by the two techniques. The correla-tion coefficient is good r = 0.82. CBPS slightlyunderestimates regurgitation when compared withcatheterization: y = 0-93 x + 1 8 .In patients with pure regurgitation, mitral oraortic, the regurgitant fraction calculated with thetwo techniques was also compared with angiographicsemi-quantitative visual evaluation which assessedthe severity of regurgitation by grading it from 1 to4. (Fig. 2) No correlation was found between thisvisual estimate and the value calculated by eithercatheterization or CBPS.Quantification of regurgitation by scintigraphy 73Table I Population data and regurgitanl fraction calculated by cathelerization and cardiacblood pool scintigraphy12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849NsmcVBGNGTMPAWHPBBFMRDMQMLMLACFFRLCSJBJBPHMCCDJBGAFAADLSMSJPJREFFFJFMGPOIBEABPAOMGPHCRPBLCLQRPGDBDBGFLJSexFFFMFMFFFMMMFMMFFMMFMFFMMMMMMFMFMMMMMMMFMMMMFMFMMAge(years)60706965346474495759325469515565616336656169245042554863603742516033502160555657615050506559635857Diagnosis seventy(1-4 degree)AI 1AI 1AI 2AI 1AI 4AI 1A I 3AI 3AI 3AI 2A I 3AI 2AI 3AI 1AI 2AI 2AI 1A I 3AI 1AI 3A I 3AI 1AI 2AI 3AI 1AI 3AI 1AI4AI 4AI 1AI 2AI 3AI 2AI 3————————MI 1MI 2MI 1MI 1MI 1MI 2MI 3MI 3MI 2MI 2MI 3MI 4MI 2MI 1MI 3MI 3MI 1MI 3MI 1————————RF%Cath.3635444042524247316036436744525155445855532952342748523141463158695430486457463471911242423202223RF%CBPS2635373639623134307226344855514556406545662844302937433843623648685344617442485557020171717203017AssociateddiseaseMSASAS, CAD (IV)MSASCAD (IV)IHSSMSASASASCAD (IV)IHSSCAD (2V)HCASASCAD (2V)CAD (2V)ASHCAS, Aortic stenosis; HC, hypertrophic cardiomyopathy; CAD, coronary artery disease, 1 or 2vessels (V); MS, mitral stenosis; IHSS: idiopathic hypertrophic subaortic stenosis.74 J-P. Melchior et al.t 8020 40 60Cardiac cathelenzalion (%)80Figure I Comparison of the regurgitant fraction obtainedby cathetenzation and cardiac blood pool scintigraphy in49 patients, n = 49, v = 0-93.V + 1-8, r = 0-82, SEE = 2 1.DiscussionCardiac blood pool scintigraphy has proved to bea useful technique in the evaluation of global andregional ventricular function. Rigo et al.li] intro-duced the concept of calculating the regurgitantfraction by comparing the stroke counts of the twoventricles. Our results and data from the litera-ture'7"131 contribute to demonstrate the clinicalusefulness of this simple principle.However one should consider some limitations inmeasuring stroke volume counts obtained by gatedequilibrium blood pool scintigraphy in LAO views.It is indeed well known that due to the superpositionof atrial and ventricular cavities, drawing a regioninterest around each ventricle is not always easy. Tofacilitate the detection of the ventricular contours,especially at the valvular levels, we used functionalimages (phase and amplitude) obtained by Fourieranalysis.The correlation we found between regurgitantfraction values by catheterization and CBPS is good(r = 0-82) but it is not optimal. Catheterization isconventionally used as 'gold standard' for the calcula-tion of the regurgitant fraction but this technique isprone to errors because of the difficulty to assess end-diastolic and end-systolic volumes and because of thehemodynamic modifications due to the contrastmedium injection. This partially explains the limita-tions of our comparison. However, we tried tominimize this problem by the following: the angio-4020nO-Ir•(ofco*1(b)•ii n m m.Anqiographic semiquantitative visual evaluationFigure 2 Comparison of the visual evaluation of regurgita-tion with the quantitative calculation of the regurgitantfraction by cardiac blood pool scintigraphy (top) andcatheterization (bottom) in patients with pure aortic ( • ) ormitral (O) regurgitation.graphic volumes were determined by two independ-ent observers, care was taken to measure the forwardcardiac output using dilution techniques (which wethink more accurate than the approximated Fickcalculation), only patients with reproducible valueswere included and cardiac output was determinedsimultaneously with ventricular angiography.In our study, the regurgitant fraction valuesobtained by CBPS were usually slightly inferior tothose obtained by catheterization. This is partiallyrelated to the introduction of a correction factor(1-2). We think, however, that this correction factor isnecessary since, in our experience and according tothe literature157"101, the stroke index ratio is usuallysuperior to one (0-8-1-7: mean 1-2) in a normalpopulation. Accordingly, the presence of a 'regurgita-Quantification of regurgitation by scinligraphy 75tion' with a calculated regurgitant fraction of lessthan 20%(SIR = 1-5) was considered as not sig-nificant. Using these criteria, all 41 patients withregurgitation had a significant regurgitation fraction(26-74%): sensitivity 100%; while seven out of theeight patients without evidence of regurgitation hada regurgitant fraction within normal limits. In these8 patients, the regurgitant fraction calculated bycatheterization was superior to 0% and varied from9 to 24% with a mean of 20%.In accordance with other studies1714 ', in ourpatients with pure aortic or mitral regurgitation wecould not find any positive correlation between thevisual evaluation of regurgitation and the quantita-tive measurements of the regurgitant fraction bycatheterization or by cardiac blood pool scinti-graphy.In conclusion, we feel that cardiac blood poolscintigraphy, an established method for determina-tion of ventricular dimensions and function, can alsobe of use in the clinical evaluation of patients withregurgitant lesions. Clinical signs and symptoms areoften unreliable to establish the severity of a valvularleak, and repeated investigations are, therefore,sometimes necessary to monitor the course of thedisease and decide on possible valve replacement.Our data show that cardiac blood pool scintigraphycan represent a safe and non invasive alternative torepeated catheterization in this setting.We arc indebted to Viviane Stucki, Godefroid Perrot andDaniel Schaller for their valuable assistance in performingthe investigations and to Anne Loutan for helping us toprepare the manuscripts.References[I] Hunt D, Baxley WA, Kennedy JW el al. Quantitativeevaluation of cineaortography in the assessment ofaortic regurgitation. Am J Cardiol 1973; 31: 696-700.[2] Sellers RD, Levy MS, Amplatz K, Lillehei CW. Leftretrograde cardioangiography in acquired cardiac dis-ease. Am J Cardiol 1964; 14- 437-47.[3] Sandier H, Dodge HT, Hay RE, RackleyCE. Quantita-tion of valvular insufficiency in man by angiocardio-graphy. Am Heart J 1963; 65: 501-13.[4] O'Rourke RA, Crawford MH. Timing of valve replace-ment in patients with chronic aortic regurgitationCirculation 1980; 61: 493-5.[5] Rigo P, Alderson PO, Robertson RM, Becker LC.Wagner HN Measurement of aortic and mitral regurgi-tation by gated cardiac blood pool scans. Circulation1979; 60: 306-11.[6] Kennedy JW, Reichenbach DD, Baxley WA, DodgeHT. Left ventricular mass: A comparison of angio-cardiographic measurements with autopsy weight. AmJ Cardiol 1967; 19: 221.[7] Lam W, Pavel D, Byrom E, Sheikh A, Best D, RosenK. Radionuclide regurgitant index1 value and limita-tions. Am J Cardiol 1981; 47: 292-8.[8] Sorensen SG, O'Rourke RA, Chaudhun TK. Noninvasive quantification of valvular regurgitation bygated equilibrium radionuclide angiography Circula-tion 1980; 61: 1089-98.[9] Thompson R, Ross I, Elmes R. Quantification of valv-ular regurgitation by cardiac gated pool imaging. BrHeart 1981,46: 629-35.[10] Bough EW, Gandsman ES, North DL, Shulkman RS.Gated radionuclide angiographic evaluation of valveregurgitation. Am J Cardiol 1980; 46: 423-8.[11] Konstam MA, Wynne J, Holman BL, Brown EJ, NeillJM, Kozlowski J. Use of equilibrium gated radio-nuclide ventriculography to quantitate left ventricularoutput in patients with and without left-sided valvularregurgitation. Circulation 1981; 64: 578-85.[12] Nicod P, Corbett JR. Forth BG el al. Radionuclidetechniques of valvular regurgitant index comparisonin patients with normal and depressed ventricularfunction. J Nucl Med 1982; 23: 763-9.[13] Klepzig H, Standke R, Nickelsen el al. Combined firstpass and equilibrium radionuclide ventriculographyand comparison with left ventricular/right ventricularstroke count ratio in mitral and aortic regurgitation.Am J Cardiol 1985; 55: 1048-53.[14] Croft CH, Lipscomb K, Mathis K el al. Limitations ofqualitative angiographic grading in aortic or mitralregurgitation. Am J. Cardiol 1984. 53: 1593 8

Quantification of valvular regurgitation by cardiac blood pool scintigraphy: correlation with catheterization

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