CONGENITAL

HEART DISEASE

Usefulness of Color-Flow Doppler in Diagnosing and in Differentiating Supracristal Ventricular Septal Defect from Right Ventricular Outflow Tract Obstruction , Achi Ludomirsky, MD, Lloyd Tani, MD, Daniel J. Murphy, MD, and James C. Huhta, MD

Color-flow Doppler is used for special localization of cardiac flows. The transeptal jet in supracristal ventricular septal defect (VSD) is directed toward the pulmonary valve and is often difficult to dlstinguish from the right ventricular (RV) outflow tract flow. Pulsed- and continuous-wave Doppler can misread the VSD jet as a stenotic lesion in the RV outflow tract. This study describes the color-flow Doppler characteristics of supracristal VSD and determines if color-flow Doppler can differentiate supracristal VSD jets from RV outflow tract flow. The study group comprised 28 patients ranging in age from 3 days to 23 years (mean 6.4), with catheterdiagnosed supracristal VSD in 14, isolated pulmonary valve stenosis in 10 and RV infundibular obstruction in 4. The echocardiographic Doppler and color-flow Doppler data of all patients were reviewed without knowledge of catheterization diagnosis. In all patients with supracristal VSD, colorflow Doppler revealed an abnormal transeptal jet directed toward the pulmonary valve that occurred 5 to 10 ms before RV oufflow tract flow was identified. VSD and RV outflow tract jet could be differentiated by pulsed- and continuous-wave Doppler alone in 10 of 14 patients (71%). In 4 patients, differentiation was possible only with color-flow Doppler and electrocardiographic gating. Associated aortic regurgitation, or a fistula, or both, were detected in 6 patients. Pulsed- and continuouswave Doppler with or without color-flow Doppler correctly identified the level of obstruction in all patients with RV outflow tract lesions (14 of 14). Supracristal VSD jet occurs in early systole and is directed toward the pulmonary valve. Color-flow Doppler is essential for the localization, assessment and accurate echocardiographic differentiation of transeptal jet from RV outflow tract flow in neonates and infants with supracristal VSD. (Am J Cardiol 1991;67:194-198)

From the Lillie Frank Abercrombie Section of Pediatric Cardiology, Baylor College of Medicine, Texas Children’s Hospital, Houston, Texas 77030. Manuscript received April 25,199O; revised manuscript received and accepted September 12,199O. Address for reprints: Achi Ludomirsky, MD, Pediatric Cardiology, Texas Children’s Hospital, 6621 Fannin Street, Houston, Texas 77030.

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wo-dimensional and Doppler echocardiography are complementary methodsfor noninvasiveanatomic and hemodynamic evaluation of ventricular septal defect (VSD). Although isolated supracristal VSD is an uncommon malformation, comprising approximately 5% of isolated VSDs, it is an important anomaly to diagnoseearly, becauseit results in progressively severe aortic regurgitation and perhaps greater susceptibility to infective endocarditis.lU3Associatedabnormalities of the aortic valve, including dilatation of the sinusesof Valsalva, prolapse of the right and left coronary cusps,and fistulas, have all been reported.4-6 Two-dimensional echocardiography can usually detect the location and size of a VSD, and hemodynamic evaluation is possiblewith pulsed and continuous Doppler echocardiography.7-gHowever, the VSD jet in a supracristal VSD is directed toward the right ventricular (RV) outflow tract and the pulmonary valve; thus, quantitation of the VSD gradient (left ventricular to RV) could be misdiagnosedas pulmonary valve or RV outflow tract obstruction. Color Doppler is a reliable and helpful modality for the spatial location and characterization of normal and abnormal intra- and extracardiac jets.‘0 We report here our experiencewith color Doppler echocardiography in the noninvasive diagnosis of supracristal VSD. This study was also performed to determine if color Doppler can be used to differentiate between supracristal VSD and RV outflow tract obstruction.

T

METHODS

The study group comprised 28 consecutivepatients, ranging in age from 3 days to 23 years, with catheterdiagnosed of supracristal VSD (n = 14) (Table I) or RV outflow tract obstruction (n = 14) (Table II). Complete 2-dimensional echocardiography,Doppler and color-flow Doppler studies were performed with mechanical or phased-array sector scanners,or both, using 3-, 5- and 7.5-MHz probes (Aloka 880 and CFM 700 Vingmed Interspec Systems). Patients were studied in the supine position and left later 30“ decubitus position. The tomographic views that were obtained included long- and short-axis parasternal views, apical 4-chamber views and subcostalshort-axis and 4-chamberviews. Electrocardiographic gating was used to differentiate between systolic and diastolic events, and to time the flows through the cardiac cycle. The initial echocardiographic examination was performed before cardiac

TABLE

1 2 3 4 5 6 7 8 9 10 11 12 13 14

I Catheterization

and Doppler Data of 14 Patients with Supracristal Ventricular

3 days+ 2 mos.+ 6 mos.7 1.5 yrs.+ 3 yrs. 3.5 yrs. 4 yrs. 5.1 yrs. 6.2 yrs. 7.1 yrs. 8.3 yrs. 9.2 yrs. 10.3 yrs. 11.3yrs.

Gender

VSD Gradient Doppler* (mm Hg)

Associated Lesions

M M F F F M M F M F M M F F

41 48 52 63 78 51 80 84 85 71 93 75 85 89

40

0 0 0 CofA AR 0 AR 0 0 AR AR AR Fistula AR

* Ventricular septal defect gradient, using modified Bernoulli equation (Pi - Pp = 4Vmaxq. t Color-flow Doppler essential for separation of supracristal ventricular septal defect from right ventricular AR = aortic regurgitation; C of A = coarctatlon of aorta; Cath = catheterization.

TABLE

II Catheterization

Septal Defect (VSD)

VSD Gradient Cath (mm Hg)

50 54 58 68 46 75 80 81 75 83 70 81 85 outflow tract flow.

and Doppler Data of 14 Patients with Right Ventricular Outflow Tract Obstruction

Pt. No.

Age

Gender

1 2 3 4 5 6 7 8 9 10 11 12 13 14

6 days 2 mos. 6 mos. 6 mos. 1 yr. 1.5yrs. 6 yrs. 6.2 yrs. 8.3 yrs. 12.7 yrs. 15.8 yrs. 16.2 yrs. 18.3 yrs. 23 yrs.

M M F F M M F M F F M M M F

Location of RV Outflow Obstruction

RVOT Gradient Cath (mm Hg)

RVOT Gradient Doppler’ (mm Hg)

Pulmonary valve Pulmonary valve Pulmonary valve lnfundibulum lnfundibulum Pulmonary valve Pulmonary valve Pulmonary valve Pulmonary valve Pulmonary valve lnfundibulum lnfundibulum Pulmonary valve Pulmonary valve

45 52 35 75 63 50 55 38 56 70 38 59 48 45

46 50 38 71 62 49 58 40 51 68 35 61 50 51

v Right ventricular outflow tract gradient, using the modified Bernoulli equation. (PI - Pe = 4Vmax2). Cath = catheterization; RV = right ventricular; RVOT = right ventricular outilow tract.

parasternal and subcostalshort-axis views. In 6 patients with aortic regurgitation, prolapse of the right coronary cusp toward the RV outflow tract was demonstrated. The best views for detection of aortic cusp prolapse RESULTS were parastemal long- and short-axis views, as well as Cardiac catheterization: All patients underwent car- the apical 2-chamber window. Suprasternal notch imagdiac catheterization. Fourteen patients had a supracris- ing revealed coarctation of the aorta in 1 patient. tal VSD. Mild prolapse of the right coronary cusp into RIGHT VENTRICULAR OUTFLOW TRACT OBSTRUCTION: the RV outflow tract associatedwith mild aortic regur- Thickened and domed pulmonary valve cusps were gitation was noted in 6 patients. In 1 patient, flow from demonstrated in all patients with pulmonary valve steright sinus of Valsalva through right ventricle fistula nosis,as well as poststenoticdilation of the main pulmowas demonstrated;mild coarctation of the aorta was de- nary artery. High parastemal short-axis scan at the levtected in another child. el of the RV outflow tract showed infundibular hyperFourteen patients had various types of RV outflow trophy and stenosisin 4 patients. The pulmonary valve, tract obstruction proved by angiography and hemody- pulmonary trunk, and right and left pulmonary arteries namic measurements: 10 patients had isolated pulmo- were normal in these 4 cases. nary valve stenosis,and 4 had RV infundibular stenosis. Pulsed-wave Doppler echocardiography: Pulsed Two-dimensional echocardiography: VENTRICULAR Doppler examination was performed along the ventricuSEPTAL DEFECT: The location of the VSD was correctly lar septal and RV outflow tract in all patients. In paidentified in all 14 patients. The supracristal VSD ap- tients with supracristal VSD, the sample volume was peared as a dropout under the pulmonary valve in the placed as closeas possibleto the defect. Turbulence and catheterization. All studies were reviewed after cardiac catheterization by an independent observer blinded to the diagnosis.

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abnormal flow were recorded in all patients. In 1 patient with sinus of Valsalva to RV fistula, continuous flow was detected through systole and diastole. In the 4 youngest patients, < 1.5 years, it was not possibleto separate the RV outflow tract jet from the VSD jet because of the close location, and further evaluation, assisted by color-flow Doppler, was necessary.Aortic regurgitation was detected in 6 patients; typical Doppler tracing of coarctation of the aorta was seenin 1. Pulsed-waveDoppler identified the level of obstruction in all patients with RV outflow tract stenotic lesions. High-velocity aliased signal was detected at the site of the obstruction, confirming the 2-dimensional imaging diagnosis. Continuous-wave Doppler: Continuous-wave Doppler directed by color-flow mapping revealed a high velocity jet (>3.2 m/s) across the ventricular septum in all patients with supracristal VSD. In the 4 youngest patients, the separation of VSD and RV outflow tract jet was possible only with the spatial guidance of the color Doppler. Continuous flow throughout the cardiac cycle was detected when the continuous-wave Doppler beam was aligned with the color display of the flow in the fistula between the sinus of Valsalva and the right ventricle. Pressuregradient estimation acrossthe coarctation site was possible by continuous-wave Doppler.

In patients with RV outflow tract obstruction, continuous-wave Doppler enabled the measurements of pressure gradient across the stenotic region using the modified Bernoulli equation. Continuous-waveDoppler, directed by color-flow mapping simplified the examination and allowed better alignment of the Doppler beam with the jet. Color-flow Doppler evaluation: Color-flow Doppler mapping detected a turbulent flow acrossthe VSD directed toward the RV outflow tract in all patients with supracristal VSD (Figure 1). In the parasternal shortaxis view, the jet was directed toward the pulmonary valve and combined with the RV outflow tract flow in early systole.The electrocardiographic gated mode was used in order to separatethe VSD and the RV outflow tract jets. The gated intervals ranged from 5 to 10 ms, depending on the color frame rate. In all patients, the transeptal shunting occurred 5 to 10 ms before RV out-

FIGURE 1. Twodimn panel) and color-flow nal short-axis view. Note dropout in the ventricular septum at 1 o’ck& (arrow) and the transeptal jet directed toward the RV outftow tract and the pulmonary valve into the main pulmonary artery on the color-flow display. A0 = aorta; ECG trig = ekctrocardiographii triggering; MPA = main pulmonary artwy; RV = right ventricle.

FIGURE 2. Two-dimensional echocardiographii and color-flow displays of supracristal ventricular septal detect from parasternal short-axis view. Upper pane/, with electrocardiographii triggering the ventricular septal defect jet is shown early in systole (open arrow). Lower panel: 10 ms later the ventricular septal detect jet is combined with the normal right ventricular outflow tract flow. A0 = aorta; HR = heart rate; PA = pulmonary artery.

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flow tract flow was identified. In the 4 infants, this separation was possible with the electrocardiographic gated mode (Figure 2). The VSD jet in all patients had a turbulent characteristic that lasted throughout systole. As it reached the RV outflow tract area, the jet was combined with the pulmonary flow. In the parasternal long-axis view, the jet was easily identified as a red or green (mosaic) flow toward the transducer from the left to right side during systole. In the patient with sinus of Valsalva to RV tistula, a mosaic spot, indicating turbulent flow, was seen in the origin of the listula throughout the cardiac cycle. Systolic and diastolic gating mode revealed flow from the sinus of Valsalva to the right ventricle during these periods. The diastolic jet of aortic regurgitation was detected in 6 patients. High-velocity and turbulent flow was seen across the coarctation site with the suprasternal view. Color-flow mapping identified the location of the RV outflow tract obstruction in all patients. Acceleration was depicted proximal to the site of obstruction, and aliasing occurred beneath the pulmonary valve or

FIGURE 3. Two-dimensional echocardiographii display from the parasternal short-axis view of a patient with pulmonary valve stenosis (upper panel). Note the thickened and domed pulmonary valve (closed arrow). In the color-flow Doppler display (lower panel), proximal acceleration depiied by red is seen proximal to the pulmonary valve, followed by a turbulent jet (mosaic pattern) across the pulmonary valve into the main pulmonary artery. MPA = main pulmonary artery; RV = right vantricle.

the infundibulum. A turbulent jet was then demonstrated distal to the obstruction (Figures 3 and 4). DISCUSSION Approximately 5% of VSDs are located high in the RV outflow tract between the crista supraventricularis and the pulmonic valve, superior1y.l’ These defects are termed supracristal or, alternatively, subpulmonic septal defects. These lesions are of particular importance because of the unusually high incidence of associated anomalies particularly involving the aortic valve. Aortic regurgitation, balloon-like dilatation of the right coronary sinus of Valsalva, prolapse of the right coronary cusp and, rarely, the left coronary cusp into the RV in,fundibulum and right coronary sinus of Valsalva to an RV fistula have all been reported to be associated with the supracristal VSD.i2 An early diagnosis and management of this lesion might preserve the aortic valve.i3 Color-flow Doppler: The location of a supracristal VSD beneath the pulmonary valve with flow toward the RV outflow tract can be misdiagnosed as RV tract ob-

FIGURE 4. lnfundibular pulmonary stenosis from the subcostal short-axis view. Upper panel, thickened infundibular area on the 2-dimensional echocardiographic display. lower panel, on color-flow Doppler display, a turbulent jet (mosaic pattern) originating from the infundibular area is clearly seen in the right ventricle (open arrow). LV = left ventricle; PA = pulmonary artery; RV = right ventricle.

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struction. In the 4 youngest infants described earlier, it REFERENCES 1. Plauth WH, Braunwald E, Rockoff SD, Mason DT, Morrow AG. Ventricular was possible to separatethe RV outflow flow from the septal defect and aortic regurgitation: clinical, hemodynamic, and surgical considsupracristal VSD flow only with color-flow mapping. A erations. Am .I Med 1965;39:552-567. careful electrocardiographic gating mode was used in 2. Nadas AS, Thilenius OG, LaFarge CC, Hawk AJ. Ventricular septal defect aortic regurgitation: medical and pathological aspects. Circulation 1964; order to separatethese 2 systolic jets and to character- with 29~862-873. ize the timing of events throughout the cardiac cycle. 3. Kerane JF, Plauth WH, Nadas AS. Ventricular septal defect with aortic The VSD jet appeared earlier than the RV outflow regurgitation. Circulation 1977;56(suppl 1):1-72-I-77. Jaffe RB, Scherer JL. Supracristal ventricular septal defects: spectrum of tract flow. The separation of these jets enabled us to 4.associated lesions and complications. Am J Roentgmoi 1977;128:629-637. align the continuous-wave beam with each of them, in 5. Otterstad JE, Ihlen H, Vatne K. Aortic regurgitation associated with ventricuorder to evaluate the left ventricular to RV pressure lar septal defects in adults. Acta Med Sand 1985;218:85-96. Steinfeld L, Dimich I, Park SC, Brown MG. Clinical diagnosis of isolated gradient. Associated lesions, such as aortic regurgita- 6.subpulmonic (supracristal) ventricular septal defect. Am J Cardiol 1972;30:19tion, listulas and coarctation of the aorta, were easily 24. detected and evaluated by color-flow and continuous- 7. Sutherland GR, Godman MJ, Smallhorn JF, Guiterras P, Anderson RH, Hunter S. Ventricular septal defects: two-dimensional echocardiographic and wave Doppler. 14 morphological correlations. Br Heart J 1982;47:316-328. Differential diagnosis: The echocardiographic dif- 6. Capelli H, Andrade JL, Somerville J. Classification of the site of ventricular defect by 2-dimensional echocardiography. Am J Cardiol 1983;51:1474ferential diagnosisof turbulence in the RV outflow tract septal 1480. should include supracristal VSD, pulmonary valve ste- 9. Snider AR, Silverman NH. Two-dimensional echocardiography in ventricular nosis and subpulmonic infundibular stenosis.Color-flow septal defects. In: Giuliani ER, ed. Two-Dimensional Real-Time Ultrasonic Imof the Heart. Boston: Martinus Nijhoff, 1985:333-344. Doppler is a reliable and helpful tool for spatial local- aging 10. Ludomirsky A, Huhta JC, Vick GW, Murphy DJ, Danford DA, Morrow ization of normal and pathologic jets in the RV outflow WR. Color Doppler detection of multiple ventricular septal defects. Circulation 1986;74:1317-1322. tract. II. Anderson RH, Lenox CC, Zuberbuhler JR. The morphology of ventricular In pulmonary valve stenosis,the jet is directed from septal defects. Perspect Pediatr Pathol 1984;8:235-268. the RV outflow tract to the main pulmonary artery. A 12. Van Praagh R, McNamara JJ. Anatomic types of ventricular septal defect green mosaic display occurs only at the level of the with aortic insufficiency. Am Heart J 1968;75:604-619. 13. Tatsuno K, Konno S, Ando M, Sakakibara S. Pathogenic mechanisms of valve cusps,indicating that high velocity and turbulence prolapsing aortic valve and aortic regurgitation associated with ventricular septal is present in this area. In infundibular pulmonary steno- defect: anatomical, angiographic, and surgical considerations. Circulation 1973; sis, the jet acceleration and turbulence depicted by color 48:1028-1037. 14. Schmidt KG, Cassidy SC, Silverman NH, Stanger P. Doubly committed Doppler is found proximal to the pulmonary valve in the subarterial ventricular septal defects: echocardiographic features and surgical implications. J Am Co0 Cardiol 1988;12:1538-1546. region of the hyperdynamic infundibulum.

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