Transesophageal Echocardiography and the Intraoperative Management of Pediatric Congenital Heart Disease: Initial Experience With a Pediatric Esophageal 2D Color Flow Echocardiographic Probe Pratima

M. Shah, MD, Scott Stewart

III, MD, Carolyn

lntraoperative color Doppler transesophageal echocardiography (TEE) was performed in 26 patients undergoing corrective or palliative surgery for congenital heart disease. Age ranged from 1 day to 15 years, and body weight ranged from 2.9 to 42 kg. Objectives of the study were to determine the smallest infant in whom the pediatric probe could be used safely, additional diagnostic value, and its role in the intraoperative assessment of the surgical repair. The insertion of the pediatric probe was possible in all 26 patients. The smallest infant in this series was a newborn weighing 2.9 kg.

I

NTRAOPERATIVE transesophageal echocardiography (TEE) has become an important technique in the assessment of surgical repair and cardiac function in patients with cardiac disease undergoing cardiac or noncardisc surgery. Until recently, in pediatric patients weighing less than 15 kg, only epicardial echocardiography’~” could be used to assess the surgical repair because small esophageal transducers were unavailable. Epicardial echocardiography has several disadvantages. It is not on-line and continuous; therefore, the operative procedure must be interrupted each time it is used. Also, it introduces a small chance for infection. Kyo et al” first described successful use of the pediatric TEE in five patients undergoing cardiac surgery. Recently, several studies have reported use of the pediatric probe in small children.‘~’ This article describes the authors’ initial experience with the pediatric probe in 26 patients. The objectives of this study were (1) to determine the smallest infant in whom the probe could be used safely, (2) to find additional diagnostic value of intraoperative TEE if any in this population, and (3) to correlate preoperative transthoracic echocardiographic findings and intraoperative findings from cardiotomy observed by the surgeon with the intraoperative TEE findings. MATERIALS

AND METHODS

A pediatric color Doppler TEE probe (Aloka Company, Ltd., Tokyo, Japan) with commercially available equipment, AIoka SSD-870 (Corometrics, Wallingford, CT), was used. Informed consent was obtained from either the parents or a guardian of the patients. The probe has a ~-MHZ transducer on the tip and contains 24 crystals. The diameter of the probe is 6.8 mm. The endoscope is approximately lOO-cm long, and has a handle with rotatory controls and a locking mechanism for remote operation of the flexible tip. This transducer scans cross-sectional images of the cardiac structures. After induction of general endotracheal anesthe-

From the Departments of Anesthesiology, Cardiothoracic Surgery Pediatric Cardiology, Strong Memorial Hospital, Universityof Rochester, Rochester, NY Address reprint requests to Pratima M. Shah, MD, Box 604, Depatiment of Anesthesiology, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642. Copyright 0 1992 by W.B. Saunders Company 1053-077019210601-0003$03.00

8

C. Calalang,

MD, and Chloe Alexson,

MD

Excellent correlation was obtained with preoperative transthoracic echocardiographic findings and operative findings. Assessment of the surgical repair was obtained in the immediate postcardiopulmonary bypass period. No shortterm complications occurred in this series. lntraoperative color Doppler TEE provided a detailed and accurate assessment of the morphology, the function of the heart, and altered the management of at least two patients. Copyright Q 1992 by W.B. Saunders Company

sia, the flexible tip of the TEE probe was lubricated with jelly and was blindly introduced in the midline into the posterior part of the pharynx. The tip was then gently positioned anteriorly by using the hand control, as the probe touched the floor of the oropharynx and then was advanced into the esophagus easily. No other tubes (nasogastric) or probes (esophageal or temperature probes) were used while performing the study. In all 26 patients, blind esophageal intubation was obtained without any difficulty. The probe was left in place during the entire duration of the surgery. The study group consisted of 14 men and 12 women whose age ranged from 1 day to 15 years. Thirteen patients were less than 12 months old, and 6 weighed less than 5 kg. After insertion of the pediatric TEE probe, complete ultrasound examination was carried out beginning at the level of the aortic valve. The probe was then advanced further to visualize the four-chamber view and then the gastric short-axis view. After obtaining two-dimensional images, pulsed wave Doppler interrogations, and color flow mapping were obtained for complete morphologic and hemodynamic evaluation of the heart. The entire examination was recorded on a half-inch videotape and was evaluated both in real time and in immediate off-line frame-to-frame analysis. Only one observer. with the prototype pediatric TEE who had I year’s experience probe and its intraoperative application, performed the complete examination. The data were also interpreted off-line by a pediatric cardiologist (CA). All infants were examined for any acute shortterm complications, ie, esophageal bleeding or esophageal perforation. Older children were questioned about symptoms of dysphagia, postoperatively.

RESULTS

The smallest patient in this series was a l-day-old newborn weighing only 2.9 kg (case 2). Intraoperative prebypass TEE findings correlated with preoperative clinical diagnosis and transthoracic echocardiographic findings in all cases (Table I). Prebypass intraoperative TEE findings correlated well with the surgeon’s observation after cardiotomy. Confirmation of an adequate repair was made in all but one patient in the immediate postbypass period. This patient is described later in this section. Postoperatively, only five patients had repeat transthoracic echocardiograms and each correlated with the immediate postbypass TEE findings. There were no immediate short-term complications or morbidity associated with use of the pediatric TEE. There were three patients in whom intraoperative TEE made a difference in their management.

Journalof Cardiothoracic and VascularAnesthes/a, Vol 6, No 1 (February), 1992: pp 8.14

9

IMPACT OF INTRAOPERATIVE PEDIATRIC TEE

Table 1. Demographics and Clinical Data of 26 Study Patients

wt. Case No.

Age

Preoperative Diagnosis

(kg)

1370995

1 Yr

9.1

VSD

1374222

5mo

4.9

Complete ECD

4mo

4.9

VSD

lntraoperative PrebypassTEE

Preoperative Echocardiogram

Perimembranous VSD with large L- > R shunt. Small LA, predominantly R- > L shunt.

MR.

“(case I) 1140677

Complete ECD with minimum

Eidir. shunt with predominantly L->R shunt, VSD inlet type, closed partially by septal leaflet of tricuspid valve.

1367505

7mo

5.7

VSD, ASD

Large L-> R shunt across VSD, small

1364705

6mo

6.1

VSD, PDA

Inlet type VSD, bidir. shunt, large PA,

1372812

4mo

4.8

TGA, S/P R-B-T

Large ASD, RVH, bilat’l. atrial dilatation.

1351260

1 vr

10.2

VSD

Perimembranous VSD, shunt predom.

1386987

1 day

R- > L shunt at second type ASD. patent ductus.

L->R. 2.9

IMC tumor (probable

*(case 2)

Rhabdomyosarcoma)

Multiple ICT with one large ECT

Large 3-cm EC mass extending into LA

behind LV, 1 ICT nearly oc-

and obstructing LV inflow, another

cluded mitral inflow

small IC mass attached to the ventricular septum.

1367318

6mo

1094041

8 Yr 23 mo

25.9

1375819

4 vr 5mo

1370532

6mo

1380620

3mo

1322508

9.2

Complete ECD

ECD, second ASD.

ASD

Second ASD with L- > R shunt.

Partial ECD

Partial ECD with L- > R shunt, minimum

14.5

ASD

Second ASD with L- > R shunt.

6.5

VSD

Perimemb. VSD with L-R shunt, RVH.

5.2

Complete ECD

Complete ECD with bidir shunt at ven-

4.4

TGA

Small atrial defect, RV enlarged.

ASD

Second type ASD with L-> R shunt.

Coarctation of Ao

Stenosis in the proximal descending Ao

9.2

MR. 1304179

tricular level, L- > R predominant. 1381950

15yr

1362640

9mo

40 6.6

with immediate distal enlargement of Ao. 0944933

13yr

1197923

5

42

Redo closure ASD

Large second type ASD with predomi-

18.2

S/P repair of partial ECD,

Moderately severe MR with decrease

nant L- > R shunt.

vr

“(case 3)

increasing MV

motion of MV leaflets. After pericar-

incompetence.

diotomy decrease in severity of MR with better mobility of MV leaflets.

27.1

PDA

1243156

9 yr 6 vr

16.4

Subaortic stenosis

1212301

5

vr

18.1

Coarctation of Ao

1390508

Small ductal flow.

PDA with shunt flow from Ao to MPA. Thick ridge seen below Ao valve annulus with turbulent flow in Ao.

Bicuspid, normal functioning Ao valve.

Narrowing in the proximal descending Ao, biscuspid Ao valve with normal function.

0935088

14yr

23.0

Single V, mitral atresia,

Single (L)V, malposition of Great

anomalous PVD of R lung to

Arteries, partial anomalous ve-

SVC, S/P PA banding

nous return, LA-V atresia, OFT

Single LV, mitral valve atresia, tricuspid valve normal.

aneurysm of unclear nature, S/P PA banding 1305345

2.5 yr

7.2

S/P repair interrupted Ao arch & PA banding, VSD

1200774

5 yr

1383112

3mo

15

Large VSD with bidirectional shunt, minimum TR, MV normal.

Tricuspid atresia

Absent tricuspid valve, large shunt at

VSD

Perimembranous VSD with predomi-

atrial level. 4.5

nantly L- > R shunt. Abbreviations: A, atrial; Ao, aorta; ASD, atrial septal defect; A-V, atrio-ventricular; Bidir, bidirectional; ECD, endocardial cushion defect; EC, extracardiac;

ECT, extracardiac tumor; Desc, descending; IC, intracardiac; ICT, intracardiac tumor; IMC, intramyocardial; LA, left atrium; L-> R,

left-to-right; LV, left ventricle; MPA, main pulmonary artery; MR. mitral regurgitation; MV, mitral valve; Occ, occludes; OFT, outflow tract; PA, pulmonary artery; Prox, proximal; PDA, patent ductus arteriosus; PVD, pulmonary venous drainage; R-B-T, right Blalock Taussig; R- > L, right-to-left; RV, right ventricle; RVH, right ventricular hypertrophy; Sec. secundum; SVC, superior vena cava; TGA. transposition of the Great Arteries; TR, tricuspid regurgitation; V, ventricle; VSD, ventricular septal defect. *Three cases described in detail.

10

Case 1 A 5-month-old infant with complete endocardial cushion defect (ECD) was initially admitted to another area hospital with severe respiratory distress. He was treated with diuretics and oxygen and discharged home on oxygen. He was admitted to the University of Rochester Medical Center with persistent symptoms of respiratory distress and hypoxia. His peripheral oxygen saturation was less than 60% on room air and improved to 85% with 40% oxygen by face mask. On clinical assessment, he was thought to have moderately severe pulmonary vascular disease as a consequence of the complete ECD with. perhaps, a primary pulmonary component. At the time of the operation, the right atrium and right ventricle were enlarged, but the left-sided chambers were normal in size. The TEE demonstrated a large right-to-left shunt across the defect and a small left-to-right shunt as well (Figs 1 A and B). The ventricular component of the defect was quite large while the atria1 component was small. Only the ventricular component was closed. The small atria1 defect was left open because of the concern that the child had severe pulmonary vascular disease in light of the large right-to-left shunt visualized on TEE. After operation, the right-to-left shunt persisted by TEE despite a relatively low pulmonary artcry pressure in the range of 40 mm Hg, systolic (Fig 2). It was suspected that the persistent right-to-left shunt was related to a directional flow phenomenon as a consequence of the proximity of the inferior vena cava orifice to the atrial defect and not as the result of severe pulmonary vascular disease as initially suspected. The child was returned to the operating room in the early postoperative period and the atrial defect was closed (Fig 3). Pulmonary pressure still remained low and he did well for the remainder of the hospital stay.

Case 2 This 2.9-kg baby boy was brought to the operating room within hours after birth for resection of a cardiac tumor, as detected on his fetal echocardiogram. Shortly following birth the transthoracic echocardiogram clearly defined a large tumor extending into the left atrium across the A-V groove and interfering with the mitral valve orifice. At the time of the operation, the TEE demonstrated a large 3-cm mass that seemed to originate from the external wall of the left ventricle, extended into the left atrium across the A-V groove, and almost completely obstructed the mitral valve (Figs 4 A and B). There was another large mass extending into the right ventricular cavity from its free wall and a third mass on the left ventricular side of the interventricular septum that were not identified preoperatively. The major portion of the tumor was excised within the left atria1 cavity and the establishment of good left ventricular inflow was documented by TEE (Figs 5A and B). The rest of the tumor was left intact as it could not be safely excised. The patient’s initial hemodynamic response was good and he was weaned from cardiopulmonary bypass with a small amount of catecholamine support. At the end of the procedure, when

SHAH ET AL

the patient was being moved from the operating table to the bed, he had progressive hemodynamic deterioration. All resuscitative efforts were unsuccessful. The autopsy showed evidence of the tumor in the lung parenchyma. Examination of the esophagus did not reveal any evidence of bleeding, laceration, or thermal burns from the probe.

Case 3 J.F. had undergone repair of a partial endocardial cushion defect at age 4. The atria1 defect was closed with a pericardial patch and the cleft in the anterior leaflet of the mitral valve was not repaired. Although the valve was competent at the time, the patient presented with significant mitral valve incompetence 1 year later. Transthoracic echocardiography demonstrated relatively immobile mitral valve leaflets with incomplete coaption and marked mitral valve incompetence. These findings were confirmed by TEE at the time of operation when mitral valve replacement was anticipated. In addition, TEE demonstrated a previously unrecognized thickened pericardial peel on the posterior surface of the left ventricle (Figs 6A to C). After this peel had been resected. the TEE demonstrated that there was improvement in coaption of the mitral valve leaflets and mitral incompetence had significantly improved even though the postpericardiectomy blood pressure was not significantly higher than the blood pressure immediately after induction. (Figs 7A and B). Thus, repair of the valve was undertaken rather than replacement based on the information provided by TEE (Fig 8).

DISCUSSION

Intraoperative two-dimensional Doppler color echocardiography is a reliable method for assessing the early results of surgical repairs. Several investigators have reported the application of this technique to assess residual shunts and valvular regurgitation. Earlier reports indicated the usefulness of two-dimensional Doppler echocardiography for intraoperative assessment of patients with congenital heart disease.‘,’ However, these studies were performed with an epicardial transducer because a small pediatric esophageal echocardiographic probe was not available. In small infants it may sometimes be difficult to image various planes even with the smallest epicardial probes. In contrast to epicardial imaging, TEE allows continuous on-line observation, does not interrupt the operative procedure. and introduces no potential risk of infection to the operative field. Kyo et al first reported intraoperative use of the pediatric TEE in patients with congenital heart diseases.“,” Recently. a few other studies have been reported.‘” In the authors’ experience, intraoperative TEE is helpful in pediatric patients in evaluating and assessing the accuracy of surgical repair. Even though this study has a small patient sample size, use of TEE definitely made a difference in the management of two patients. In case 2, the extent of the tumor was clearly larger when seen on TEE than with a transthoracic study. Therefore, the operative plan was

IMPACT OF INTRAOPERATIVE

PEDIATRIC TEE

Figures l-4

SHAH ET AL

Fig 1. (A) lntreoperative two-dimensional TEE of a 5-month-old infant with complete endocardial cushion defect (arrow). (6) Intraoperative M-mode color Doppler TEE demonstrating shunt across the defect (arrow). LA, left atrium; RA, right atrium; LV; left ventricle. Fig 2. (second row, left, p 11) Postbypass transesophageal color flow mapping (case 1) demonstrating (arrow) persistent right-to-left shunt at atrial level. IA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle. Fig 3. (second row, right, p 11) lntraoperative TEE (case 1) in immediate postbypass period done during the second thoracotomy 24 hours later. Note the closure of the atrial defect (arrow). RA, right atrium; RV, right ventricle; LA, left atrium; LV, left ventricle. Fig 4. (A) lntraoperative two-dimensional TEE of a newborn patient with a large extracardiac tumor (T), extending across the A-V groove into left atrium and obstructing mitral valve. (6) Color flow mapping showing minimal flow (arrow) across the mitral valve. LA, left atrium; LV, left ventricle; RV, right ventricle; T, tumor. (Captions

continued

on opposite

page)

IMPACT OF INTRAOPERATIVE PEDIATRIC TEE

(captions continued from opposite page) LA, left atrium; RA, right atrium; AML, anterior mitral leaflet; PML, posterior mitral leaflet; LA, left atrium; T, tumor. Fig 6. (Middle, p 12) TEE done immediately after induction of anesthesia at mitral valve during systole (A) and diastole (B). Note how mitral leaflet motion is restricted. The arrow points to the thickened pericardial peel. (C) Evidence of mitral regurgitation as seen by color flow mapping. L, left atrium; R, right ventricle; MR. mitral regurgitation. Fig 7. (Top left, this page) TEE et mitral level after the resection of the pericardial peel. Note the increase in the mobility of the mitral valve (A) end decrease in amount of mitral regurgitation (B) as semiquantitated by color flow mapping. aml, anterior mitral leaflet; pml, posterior mitral leaflet; MR. mitral regurgitation. Fig 6. (Top, p 12) (A) Immediate postbypass TEE in the same patient (case 2) showing freeing up of the tumor from the mitral valve and (B) establishment of good left ventricular inflow as demonstrated by color flow mapping. The arrow shows the remainder of the tumor.

revised to perform a palliative resection of the tumor rather than total excision. In addition, satisfactory mitral valve function could be demonstrated after cardiopulmonary bypass was discontinued. In case 3, pediatric TEE led to a significant change in the type of surgical procedure performed. Because of improvement in left ventricular function after pericardiectomy and a significant decrease in the amount of mitral regurgitation, mitral valvuloplasty rather than mitral valve replacement was performed, preserving the native valve. The mitral valve function could be evaluated accurately with TEE immediately after coming off cardiopulmonary bypass. Additional diagnostic information also was noted in case 1, in which the atria1 defect could have been closed during the first operation, thus avoiding a second thoracotomy within 24 hours. This case occurred early in the authors’ experience with intraoperative pediatric TEE. Thus, they were reluctant to alter the course of the treatment. However, during the second thoracotomy, immediate and accu-

Fig 6. (Top right, this page) TEE after mitral valve repair. Note the decrease in the amount of mitral regurgitation (arrow) as seen with color flow mapping. pml, posterior mitral leaflet.

rate assessment of the surgical repair was obtained using TEE. The exact role of intraoperative two-dimensional TEE in the pediatric and infant population has yet to be defined. In addition, the specificity, sensitivity, and limitations of intraoperative TEE in pediatric patients need to be investigated in larger series. In this series, only five patients had a postoperative follow-up transthoracic two-dimensional color Doppler ultrasound. In these five patients, the immediate postbypass TEE findings corroborated with the later examination. Recently, Kaulitz et al reported that TEE provided a more detailed and accurate assessment of atria1 baffle morphology and function than that derived by either precordial ultrasound or cardiac catheterization.’ In this series, no immediate short-term complications with use of a pediatric TEE probe even in an infant weighing only 2.9 kg were observed. Further studies need to be performed to determine morbidity or complications caused by pediatric TEE.

14

SHAH ET AL

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ageal Doppler echocardiography on pediatric cardiac surgery. lnt J Cardiac Imag 4:41-42, 1989 6. Cyran SE, Kimball TR, Meyer RA, et al: Efficacy of intraoperative transesophageal echocardiography in children with congenital heart disease. Am J Cardiol63:594-598, 1989 7. Stumper 0, Kaulitz R, Elzenga NJ, et al: The value of transesophageal echocardiography in children with congenital heart disease. J Am Sot Echo 4:164-176, 1991 8. Muhiudeen I, Roberson D, Silverman N, et al: Intraoperative echocardiography in infants and children with congenital cardiac shunt lesions: Transesophageal versus epicardial echocardiography. J Am Co11 Cardiol 16:1687-1695, 1990 9. Kaulitz R, Stumper OFW. Geuskens R. et al: Comparative values of the precordial and transesophageal approaches in the echocardiographic evaluation of atrial baffle function after an atrial correction procedure. J Am Coil Cardiol 16:686-694, 1990