Echocardiographically Guided Repair of Tetralogy of Fallot

Giuseppe Santoro, MD, Bruno Marino, MD, Duccio Di Carlo, MD, Roberto Formigari, MD, Andrea de Zorzi, MD, Ennio Mazzera, MD, Gabriele Rinelli, MD, Carlo Marcelletti, MD,

huskppe De Simon&, MD, and Luciano Phsquini, MD

Although 2dimensional, Doppler, color flow echocardiography is accepted as a safe dia@os- tic method to guide the surgical treatment of certain heart defects, cardiac catheterization re- mains mandatory for patients wlth tetralogy of Fallot. Based on the excellent diagnostic cowela- tion between echocardiography and angiocardi- o&aphy, a policy of echoqguided primary repair of uncomplicated, selected cases of tetralogy of Fallot was introduced at Ospe&le Bambino Gesu’. In the last 5 years, of 139 patients who had surgery for tetralogy of Fallot, 105 undelc went primary repair. In 56 patients (53.3%), surgery was guided only by echocardiography (group I). In the remaining 49 patients (46.7%) @toup II), unclear ima@ng of cardiovascular anatomy (n q 23), or echo-suspected associated malformations (n = 26) prompted cardiac cathe- tettzation. The 2 groups dii not dir in age and weigM at surgery. lntraoperative examlnatlon did not show diagnostic errors In patients of group I; cardiac catheterizathk and surgery con- firmed the suspected associated anomalies in 16 of 26 patients of @oup II (36.4% falsepositive). Echocardiography showed an overall sensitivity of 100% and specificity of 65% for detection of associated malformations.

In conclusion, echocardiography proved to be adequate for selection of patients with uncom plicated forms of tetralogy of Fallot for primary repair.

(Am J Cardiol1994;73:66W3ll)

From Pediatric Cardiology and Cardiac Surgerv, Owedale Bambino Gesu’, Rome, Italy. Man&ript received Junelj, 1993; revised manu- script received September 20, 1993, and accepted September 21.

Address for reprints: Bruno Marino, MD, Pediatric Cardiology, Ospedale Bambino Gesu’, Pzza S. Onofrio, 4,00165 Roma, Italy.

T wo-dimensional echocardiography with Doppler and color flow analysis is currently a reliable di- agnostic method for surgical indication of certain

heart defects. Numerous reports have been published on surgical palliation’” or repair1,613 based on echocar- diography alone. However, in patients with tetralogy of Fallot, cardiac catheterization and angiography continue to be regarded by most cardiologists and surgeons as a mandatory diagnostic step. i4,i5 Because the diagnostic data needed for the preoperative assessment of patients with tetralogy of Fallot are anatomic in nature,14’15 tak- ing into account the excellent diagnostic correlation be- tween echocardiographic and angiographic pictures,15-19 we adopted a policy of primary repair based only on echocardiography for selected patients with this cardiac malformation. In this study, we analyzed a 5-year expe- rience with echocardiography for guidance of primary repair of tetralogy of Fallot.

METHODS Between October 1987 and October 1992, 139 pa-

tients with tetralogy of Fallot underwent a surgical pro- cedure at our institution. Elective repair of tetralogy of Fallot is usually performed in patients aged >l year and weighing >,6 kg. Thirty-four patients received a sys- temic-to-pulmonary shunt because of young age or clin- ical condition (i.e., intractable cyanotic spell with sys- temic acidosis), or both, and were excluded from this analysis. In most of these patients, the diagnosis and sur- gical indication were obtained by echocardiography alone. The records of the remaining 105 patients who underwent primary repair (75% of the total population with tetralogy of Fallot) were reviewed. All patients un- derwent preoperative clinical examination, electrocar- diography, chest x-ray and complete echocardiographic study.

Echocardiography: The study was performed with a Hewlett-Packard Sonos 1000 sonographer with 5.0 and 3.5 MHz phased-array transducers appropriately focused according to the size of the patient. In each case, a com- plete examination was performed with 2-dimensional, Doppler and color flow techniques by subxyphoid, api- cal, parasternal and suprastemal approaches. In particu- lar, subxyphoid views were used to assess the size and position of ventricular septal defects, and the morphol- ogy of the right ventricular outflow tract.i6J7 Chloral hy- drate was used for sedation when necessary. Each echocardiographic investigation included the study of pulmonary and systemic venous connections, atria, atri- oventricular valves, ventricles, great arteries (connec- tions and relations) and coronary arteries.20 Doppler peak instantaneous gradients through the right ventricular out-

808 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 73 APRIL 15. 1994

flow tract were calculated using the simplified Bernoulli equation. Color flow imaging was added with the aim of detecting the presence of additional ventricular septal de- fects,2t*22 pulmonary artery branch stenoses, patent duc- tus arteriosus and other associated anomalies.

Two groups of patients were identified. Group I (n = 56; 53.3%) included patients who underwent echo- guided primary repair. Group II (n = 49; 46.7%) included patients who were evaluated by echocardiography and cardiac catheterization. There was no significant differ- ence in age and weight between the 2 groups (Table I). In group 1, we selected only patients with the usual anatomy (unrestrictive malalignment ventricular septal defect with overriding of the aortic root, and infundibu- lar pulmonary stenosis with confluent pulmonary arter- ies) (Figures 1 and 2).t5 In these patients, echocardiog- raphy permitted visualization of all cardiac structures and excluded associated malformations. In group II, the indication for cardiac catheterization resulted when: (1) echocardiographic study was considered to be unsatis- factory owing to incomplete imaging of cardiovascular structures (n = 23; 47%), and (2) echocardiography sug- gested the presence of associated cardiac anomalies (n = 26; 53%). The diagnostic findings were compared with those observed at surgery or autopsy, or both, and false- positive and false-negative indexes were calculated. From these observations, the sensitivity and specificity of echocardiography for the detection of associated mal- formations were assessed. Hospital mortality was eval- uated for each group. Statistical analysis was performed by unpaired Student’s t test and chi-square test.

RESULTS Group I (echocardiographically guided surgical CB

pair): Echocardiographic diagnosis was confirmed con- sistently at surgery. All patients had the usual anatomy without associated anomalies.r5 Hospital mortality was 5.4% (3 of 56 patients).

Group II (echocardiographic and angiocardb graphic preoperative assessment): Associated car- diac malformations, suspected at echocardiographic study in 26 patients, were confirmed at cardiac catheter- ization in 16 (38.4% false-positive index). Intracardiac

TABLE I Patient Data at Surgical Repair (n = 105)

AgeCdays) Weight (kg)

Overall 696 f. 600 (63-2,919) 10.5 2 5.5 (2.4-22.0) (n = 105)

Group1 (n = 56) 646 + 576 (83-2,919) 10.9 + 6.8(2.4-50.0) (53.3%)

Groupllh = 49) 752 + 627 (63-2,690)* 10.8 5 3.8 (2.5-22.0)* (46.7%)

*p = NS versusgroup I,

anomalies were confirmed in 4 patients. One patient had atrioventricular canal and 2 other children had accessory muscular ventricular septal defects. The remaining pa- tient had a dual-chambered right ventricle due to a hy- pertrophic muscular septal band. Anomalies of the pul- monary arteries were confirmed by angiography in 11 of 13 patients (84.6%). At echocardiography, 2 patients had multiple stenoses of both proximal branches of the pul- monary arteries, and angiography confirmed a diffuse mild to moderate hypoplasia of the pulmonary arterial tree. Two other patients underwent cardiac catheteriza- tion because the echocardiographic study did not image the left pulmonary artery; at angiography, the pulmonary artery originated from a small patent ductus arteriosus. In another patient, the echocardiographic diagnosis of associated aortopulmonary window was confirmed by cardiac catheterization. Of the other 8 patients, echocar- diographic suspicion of stenosis or hypoplasia of the left pulmonary artery was confirmed at cardiac catheteriza- tion in 6. Angiography confirmed the presence of an anomaly of the coronary arteries in only 1 of 9 patients (11.1%). In each patient, the presumed anomaly at echocardiography was origin of the left anterior de- scending artery from the right coronary artery. In 4 false- positive cases, a large conal branch of the right coronary artery crossing the pulmonary infundibulum was found, simulating on echocardiography an anterior descending coronary artery from the right. The 23 patients catheter- ized because of incomplete echocardiographic imaging showed usual anatomy. In group II, the hospital mortal- ity was 12%. No early or late mortality was related to an incorrect diagnosis.

FIGURE 1. Subxyphoid long-axis view in patient with tetralogy of Fallot and usual anatomy. Note unrestrictive malalignment ventricular septal defect with overriding of aortic root. A q

aorta, LA = left atrium; LV = left VBR tricle; RV = rigM ventricle.

ECHOCARDIOGRAPHY FOR SURGERY OF TETRALOGY OF FALLOT 809

TABLE ii Associated Malformations and Diagnostic Accuracy of Two-Dimensional Doppler Color Flow Echocardiography in Patients with Tetralogy of Fallot

Echocardiographic Diagnosis Specificity Sensitivity (

Intracardiac anomalies (n = 4) AV valve abnormalities (n = 1) Accessory VSD (n = 2)

100% (4/4) 100%

Dual-chambered RV (n = 1) Pulmonary artery anomalies (n = 13)

Hypoplastic pulmonary arterial tree (n = 2)

87% (11/13) 100%

Pulmonary artery discontinuity (n = 2) Aortopulmonary window (n = 1) Left pulmonary artery stenosis (n = 8)

Coronary artery anomalies (n = 9) 68% (l/9) 100%

AV = atnoventricular: RV = right ventricle; VSD = ventricularseptal defect.

There was an increase in diagnostic confidence with time, such that echocardiography alone was used in 63.3% of patients (31 of 49) after August 1990, com- pared with 44.6% (25 of 56) between October 1987 and August 1990.

DISCUSSION Integrated echocardiographic study (2-dimensional,

Doppler and color flow) is a diagnostic method that has markedly modified the management of infants and chil- dren with congenital heart defects. Because of the good correlation between echocardiography and angiography, surgical palliation’-5 and repaie13 of congenital heart disease guided by echocardiography alone has been de- scribed. This technique improved the cost-effectiveness ratio in the diagnosis of congenital heart disease.9g”‘12 To our knowledge, only 2 studies have reported the possi- bility of using this diagnostic technique for the surgical management of patients with tetralogy of Fallot.*2~‘3 In October 1987, a policy of primary repair of uncompli- cated cases of tetralogy of Fallot guided by echocardi- ography alone was introduced at our institution. Only patients with the usual anatomy, without previous pal-

liative operations, and with unequivocal visualization of all cardiac structures and confident exclusion of associ- ated cardiac anomalies were entered in the study proto- col. Attention was given to the position and size of the ventricular septal defect,18,19 additional ventricular sep- tal defects,2’,22 morphology of the right ventricular out- flow tract,‘6%17 and anomalies of the pulmonary arterial tree’4,2” and coronary arteries.24q25 Fifty-six infants and children (53.3%) with tetralogy of Fallot underwent sur- gical repair based on echocardiographic diagnosis alone. In all patients, the echocardiographic diagnosis was con- firmed at surgery without 1 false-negative. In patients who underwent cardiac catheterization because of the suspicion of associated malformations, sensitivity and specificity of echocardiography were high for intracar- diac malformations and pulmonary vascular abnormali- ties, but low for coronary arterial anomalies (Table II). In this respect, the only relevant anomaly for surgical correction is the origin of the anterior descending branch from the right coronary artery crossing the pulmonary infundibulum.24q25 If this anomaly is present, an extra- cardiac valved conduit may be needed and an older age for surgery is advisable. The use of pre- or intraopera- tive transesophageal echocardiography may improve the diagnostic accuracy and avoid the need for catheteriza- tion owing to previous poor echocardiographic imaging. In conclusion, primary repair of uncomplicated tetralogy of Fallot can be confidently performed in selected chil- dren with the guidance of echocardiography alone. In our opinion, cardiac catheterization should be reserved for patients in whom the echocardiographic diagnosis is not fully certain or suggests associated cardiovascular anomalies. This analysis pertains to patients who are considered for repair in relation to certain age and weight, according to the policy of our institution. How- ever, there is no reason not to use this diagnostic method in younger infants, if surgical repair at the onset of symp- toms is preferred.

Acknowledgment: We thank Dr. James B. Seward, MD, for suggestions and reviewing the manuscript.

FiGURE 2. Subxyphoid right oblique view in patient with tetraiogy of Faiiot and usual anatomy. Note infundibuiar pulmonary stenosis due to maiaiigned outlet septum, confluent pulmonary ale terks (R aad L), and communication betweelr right ventrkie (RV) and aorta (A). LA q left atrium: P q main puC monary artery: RA q right atrium.

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