Screening for congenital heart disease with the four-chamber view of the fetal heart Patrizia Vergani, MD, Silvana Mariani, MD, Alessandro Ghidini, MD, Riccardo Schiavina, MD, Maria Cavallone, MD, Anna Locatelli, MD, Nicola Strobelt, MD, and Patrizia Cerruti, MD Monza, Italy OBJECTIVE: Our objective was to determine the efficacy of the four-chamber view of the fetal heart in routine ultrasonographic examination as a screening tool for congenital heart defects. STUDY DESIGN: A prospective cohort study compared the detection rate of congenital heart defects among 5336 pregnant women screened with the ultrasonographic four-chamber view of the fetal heart from 1987 through 1989 with that among 3680 patients examined ultrasonographically without the four-chamber view during the 2 preceding years (1985 through 1986). All patients were followed until delivery or termination of pregnancy, and clinical or autopsy confirmation of prenatal findings were obtained on all cases. RESULTS: The overall incidence of congenital heart diseases was 5.2 per 1000 (47/9016). During the years 1985 through 1986 15 neonates with congenital heart diseases were identified, seven of which were prenatally diagnosed (sensitivity 43%). During the period 1987 through 1989 a four-chamber view of the fetal heart was obtained in 95% of cases; 32 cases of congenital heart disease occurred, 26 of which were diagnosed antenatally (sensitivity 81%, p = 0.01). Two false-positive diagnoses were made during the second time period, giving a specificity of 99.9%. CONCLUSION: The four-chamber view of the fetal heart is easily obtained, does not significantly increase the duration of a routine ultrasonographic examination, and has an excellent sensitivity for the identification of congenital heart diseases. (AM J OSSTET GVNECOL 1992;167:1000-3.)

Key words: Congenital heart disease, ultrasonographic screening

Most cases of congenital heart disease are of structural rather than functional origin. Therefore distortion of the normal cardiac anatomy is the most important finding on antenatal ultrasonographic evaluation. The incidence of congenital heart disease has been reported as two to three per 1000 among newborns, I but it is expected to be higher in fetuses. Targeted echocardiographic examination of the fetal heart and of the afferent and efferent vessels has an excellent detection rate for congenital heart disease. However, it is a timeconsuming examination and it requires specific expertise. Therefore fetal echocardiograms have traditionally been done only in cases at high risk for congenital heart disease. Unfortunately, the common indications for echocardiography will only enable detection in a minority of cases; the incidence of congenital heart disease is only 1% among patients referred because of a positive family history, 1.6% among those with a fetal

From the Departments of Obstetrics and Gynecology and Cardiology, Istituto di Scienze Biomediche Ospedale S. Gerardo. Presented at the Twelfth Annual Meeting of the Society of Perinatal Obstetricians, Orlando, Florida, February 3-8, 1992. Reprint requests: Alessandro Ghidini, MD, Department of Obstetrics, Gynecology and Reproductive Sciences, The Mount Sinai Medical Center, Box 1171, One GustaveL. Levy Place, New York, NY 10029.

616139681

arrhythmia, 2% among those exposed to known teratogens, and 3.1 % among diabetic mothers.2 The incidence increases to 23% in cases of known extracardiac anomalies, 25% in cases of known aneuploidies, and 33.3% in cases of nonimmune hydrops. The highest incidence (50%) of congenital heart disease occurs in cases referred because of a suspected congenital heart disease on a routine ultrasonographic scan. 2 In fact, the majority of congenital heart diseases do not have known risk factors. The four-chamber view of the fetal heart has been proposed as a method to improve the sensitivity oflevel I scans. 3.4 This scanning plane has several features that make it an appealing screening tool: It can be easily taught, it is feasible in about 95% of cases, and it appears to have a high sensitivity for the detection of congenital heart disease. Indeed, a retrospective study showed that 92% of all congenital heart diseases diagnosed at a prenatal echocardiographic center had abnormal four-chamber sections. 2 It has been argued, however, that four-chamber views obtained in a screening fashion by less skilled obstetric ultrasonographers could miss a large number of major heart lesions.' No study has been published so far in the English literature evaluating in a prospective fashion the usefulness of the four-chamber view of the fetal heart as a screening

Volume 167 Number 4, Part

Four-chamber view of fetal heart

1001

I

Table I. Cardiac anomalies identified in utero Lesion

11985-198611987-1989

Ventricular septal defect Complete atrioventricular septal defect Hypoplastic left heart syndrome Interatrial and interventricular defects Ectopia cordis Ebstein anomaly Septal hypertrophy Cardiomegaly Situs inversus Abnormal tricuspid valve Aneurysm of the foramen ovale Single ventricle Cardiac rhabdomyoma

0 0 0 0 0

TOTAL

7

0 I

2

6 3

4*

0

3

0

3 I I 0

I I

2

2 2* I I I

28

Table II. False-negative diagnosis with the four-chamber view Lesion

Ventricular septal defect Atrial septal defect Transposition of great vessels Cardiomegaly with atrial septal defect Dextrocardia with aortic coarctation Tricuspid atresia and hypoplastic right ventricle Truncus arteriosus with ventricular septal defect and atrial septal defect Tetralogy of Fallot

1985-1986

1987-1989

3

I I

2

2

0 I

0 0 0

0 0

8

TOTAL

6

*One of which was a false-positive diagnosis. tool for the detection of congenital heart disease in a low-risk population. We verified this hypothesis in a prospective cohort study, where the sensitivity of a four-chamber view for congenital heart disease in one group of patients was compared with that of a historic group where a standard ultrasonographic examination was performed. Material and methods

Between January 1985 and December 1989 a total of 9016 women underwent routine ultrasonographic examinations at the Ospedale S. Gerardo, Monza, Italy. Of these, 3680 were examined during the years 1985 through 1986, whereas the remaining 5336 scans were performed during the years 1987 through 1989. Routine ultrasonographic scans were performed at 18 to 20 weeks' gestation; patients with risk factors for congenital heart disease (i.e., diabetes, family history of congenital heart disease, teratogen exposure) were subsequently sent for a detailed echocardiographic examination. All patients underwent determination of fetal biometry and morphologic types with 3.5 and 5.0 MHz sector scanners (Toshiba SSA-90A, Tokyo, and Ultramark 4, Advanced Technology Laboratories, Bothell, Wash.). The operators were obstetricians with degrees of experience in prenatal ultrasonography ranging from 2 months to 8 years. When a suspicious four-chamber view was detected by a ultrasonographer of recent training, confirmation of the findings by a more experienced ultrasonographer was required before the patient was sent for an echocardiographic examination. This was aimed at reducing the number of false-positive diagnoses. During the first study period fetal cardiac anatomy evaluation was left to the operator's initiative without the routine use of a four-chamber view. We estimate that in about 20% of cases a four-chamber view was visualized. Starting in January 1987, an attempt at the

Table III. Outcome of cardiac anomalies identified in utero Neonatal death

Lesion

Ventricular septal defect Complete atrioventricular septal defect Hypoplastic left heart syndrome Interatrial and interventricular defects Ectopia cordis Ebstein anomaly Septal hypertrophy Cardiomegaly Situs inversus Abnormal tricuspid valve Aneurysm of the foramen ovale Single ventricle Cardiac rhabdomyoma TOTAL

2

3

2

5

0

2

0

0

0

0

I

0 0 0 2 0 0

0

0

0

0 I

0 0

0 0

8

7

12

3 0 0 0 0 0

2 I

0 0

four-chamber section of the fetal heart was made on all patients. This view is imaged in a transverse plane of the fetal thorax just above the diaphragm." It allows visualization of the atrial and ventricular chambers and walls, the interventricular septum, the foramen ovale, and the tricuspid and mitral valves. This view was considered abnormal if any of the following findings were detected: displacement of the heart from the normal site and orientation, ventricular disproportion, myocardial hypertrophy, dilatation or hypoplasia or any cardiac chamber, septal defects, or atrioventricular valve deformity. Any of these abnormalities prompted an echocardiographic evaluation. Confirmation of the diagnosis led to a multidisciplinary approach, with in-

1002 Vergani et al.

October 1992 Am J Obstet Gynecol

Table IV. Outcome of karyotype anomalies associated with prenatal congenital heart disease Chromosomal anomaly

Total

Trisomy 21 Trisomy 18 Monosomy X Triploidy Trisomy 13 47,XX,I5+ 160,XXX

7 7 2 2 2 I

In utero death

Elective abortion

Neonatal death

I 2

0

4 3 2

2

0

0

0 0

0 0

I

volvement of a pediatric cardiologist, a geneticist, and the obstetrician, so that the most accurate information could be given to the parents to help them in the decision-making process. Chromosome analysis was performed in all cases: on amniotic fluid cells in abnormal cases detected ante natally and on peripheral lymphocytes in cases diagnosed postnatally. All patients were followed until delivery or termination of pregnancy, all of which occurred at our hospital. Clinical or autopsy confirmation of abnormal antenatal findings was obtained on all cases. During the study period newborns were admitted for at least 3 days after normal vaginal delivery and 5 days after cesarean section. Newborns subsequently returned for followup examination after 1 week. The neonatologic and the obstetric ultrasonographic team met weekly to exchange information regarding cases of anomalies diagnosed prenatally or postnatally. This feedback from the neonatalogists was essential in assessing the rate of false-negative diagnoses.

Results Overall, 47 cases of congenital heart disease occurred during the 5-year period, giving an incidence of 5.2 per 1000 (47/9016). During the years 1985 and 1986 15 cases of congenital heart disease were identified among 3680 patients, seven by routine prenatal ultrasonographic scan and eight in the neonatal period. The sensitivity of prenatal testing was therefore 46.7%. No false-positive diagnoses were made. During 1987 through 1989 the four-chamber view of the fetal heart was introduced into the examination and was successfully obtained in 95% of cases. A total of 32 cases of congenital heart disease occuned; suspicion was raised by prenatal routine four-chamber view scans in 28 cases, and in 26 cases the diagnosis was confirmed by echocardiographic examination, yielding a sensitivity of 81 %. There were two falsepositive diagnoses, giving a specificity of 99.9%. One was an apparent abnormal insertion of the tricuspid valve, and the second was a relative hypoplasia of the left ventricle. Neither suspicion was subsequently confirmed by echocardiography.

I

0

2 I

Alive at 1 mo

2

0 0 0 0 0

The types of cardiac anomalies diagnosed antenatally are reported in Table I. False-negative diagnoses for the two study periods are reported in Table II. Among the seven cases of congenital heart disease diagnosed in utero during the period 1985 through 1986, four died in utero and three during the neonatal period. Of the 26 cases diagnosed during 1987 through 1989, eight were electively terminated, three died in utero, 10 died during the neonatal period, and five survived. The outcome of cases diagnosed in utero subdivided by type of cardiac anomaly is presented in Table III. The outcome of the cases with false-negative prenatal diagnoses of congenital heart disease was as follows: during 1985 through 1986, four of the eight cases died during the neonatal period and four survived and during 1987 through 1989 two of the six cases died shortly after birth and four survived. In summary, the in utero fetal death rate in the cases of congenital heart disease was 17.9% (7/39) (after exclusion of termination of pregnancies), and the neonatal mortality rate was 59.4% (19/32). The incidence of chromosomal anomalies in these cases of congenital heart disease was 44.7% (21147). The outcome of these cases is shown in Table IV.

Comment It has been suggested that incorporation of the fourchamber view of the fetal heart into routine obstetric scanning may improve the diagnostic rate of congenital heart disease. 3 A report from an echocardiographic center in England noticed an increase over the years in referrals of congenital heart disease cases suspected prenatally during routine uitrasonographic scans.4 This change was attributed to the education of the obstetricians and ultrasonographers in obtaining the four-chamber view during routine ultrasonographic examinations. The authors speculated that over 60% of severe congenital heart diseases could be detected by means of the fourchamber view. Indeed, a retrospective study on all fetal congenital heart diseases detected at an echocardiographic center showed that 92% of them had an abnormality visible with the four-chamber view. 2 It has been argued that such a high diagnostic yield

Four-chamber view of fetal heart

Volume 167 Number 4, Part 1

would not be reproducible in less expert hands, because the information that an echocardiographer can obtain from the four-chamber view is certainly greater than the one a normal ultrasonographer would gather from the same scan. 5 In this context our results are reassuring in that the sensitivity of the four-chamber view used during level I ultrasonographic examinations in an unselected population (constituted predominantly of patients at low risk for congenital heart disease) was 81 %. Although this result is lower than expected by Copel et al.,2 it is still a definite improvement when compared with the 43% sensitivity of a routine ultrasonographic screening that does not use this diagnostic scanning plane. The two groups in our study were similar in terms of gestational age and the ultrasonographer's experience; still there was a significant improvement in the diagnostic sensitivity with the four-chamber view. Although we did not examine how the operator's experience and the gestational age at the time of the screening affected the detection rate, it is probable that both factors can significantly affect the sensitivity of the four-chamber view. The introduction of this scanning plane in a routine ultrasonographic examination could generate a number of false-positive diagnoses, thereby creating unnecessary anxiety in the patients and needless crowding of echocardiographic centers. However, our experience is that false-positive diagnoses with the four-chamber view are rather uncommon. It can also be expected that the more familiar the ultrasonographer becomes with this scanning plane, the lower is the false-positive rate. As to the false-negative diagnoses, because in our series a neonatal echocardiographic examination was performed only in the presence of a clinical suspicion of congenital heart disease, minor heart defects may have gone undiagnosed both prenatally and during the neonatal period. However, the incidence of congenital heart diseases in our series (5.2/1000) compares favorably with the data available in the literature, where is appears that the cumulative incidence of definite congenital heart disease per 1000 children increases from 3.3 at birth to 4.0 at the end of the first week of neonatal life, 5.2 by the end of the first month, and 7.8 at the end of the first year. 6 The incidence of congenital heart diseases among fetuses was not available so far, because the literature on prenatal diagnosis of fetal cardiac anomalies comes from referral centers. After exclusion of the eight cases electively terminated, the spontaneous intrauterine death rate was 17.9% (7/39) in the entire population and 28% (7/25) of the series detected antenatally; four of the seven cases occurred in association with chromosomal abnormalities. This is in

1003

agreement with data from echocardiographic centers that reported a fetal death rate of 14% to 25.7% in patients with congenital heart diseases. 7 • 8 A diagnosis of congenital heart disease should prompt determination of the fetal karyotype; the incidence of chromosomal anomalies among cases detected in utero has been reported to be as high as 20%.7.8 As expected, this is higher than the incidence in neonatal series (5% to 10%), because many cases die in utero or are selectively terminated. However, in our series, the incidence of chromosomal abnormalities was much higher (44.7%). One possible explanation for this finding is that not all fetuses in the series reported from referral centers underwent cytogenetic evaluation. Cardiac anomalies diagnosed by prenatal ultrasonographic examinations have traditionally been so severe that prognosis was uniformly poor. In a series of 222 cases in which a diagnosis of congenital heart disease was made and pregnancy continued, 57 died in utero, 87 died during the neonatal period, and only 78 survived the neonatal period. 8 Although our series is too small to draw any conclusion, this perspective may change with the introduction of the routine four-chamber view, where also minor defects may be observed. Detection of congenital heart disease by prenatal screening programs can lead in selected cases (e.g., arrhythmias) to in utero therapy; cases requiring postnatal surgical procedures can have better chances of a favorable outcome by antenatal transfer of the mother to a center with pediatric cardiac facilities, so that neonatal care can be optimal. REFERENCES 1. Fyler DC, Buckley LP, Hellenbrand WE, Cohn HE. Report of the New England regional infant care program. Pediatrics 1980;65:375-461. 2. Copel]A, Pilu G, Green], Hobbins]C, Kleinman CS. Fetal echocardiographic screening for congenital heart disease: the importance of the four-chamber view. AM] OBSTET GYNECOL 1987; 157:648-55. 3. DeVore GR. The prenatal diagnosis of congenital heart disease-a practical approach for the fetal sonographer. ]CU 1985;13:229-45. 4. Allan LD, Crawford DC, Chita SK, Tynan MJ. Prenatal screening for congenital heart disease. BMJ 1986; 292: 1717-9. 5. Silverman NH. Apical four-chamber ultrasonography as screen for congenital heart disease [Letter]. AM] OBSTET GYNECOL 1989;160:1017. 6. Hoffman ]IE, Christianson R. Congenital heart disease in a cohort of 19,502 births with long-term follow-up. Am] CardioI1978;42:641-7. 7. Allan LD. Diagnosis of fetal cardiac abnormalities. Arch Dis Child 1989;64:964-8. 8. Sharland GK, Lockhart SM, Chita SK, Allan LD. Factors influencing the outcome of congenital heart disease detected prenatally. Arch Dis Child 1991;66:284.

Screening for congenital heart disease with the four-chamber view of the fetal heart.

Our objective was to determine the efficacy of the four-chamber view of the fetal heart in routine ultrasonographic examination as a screening tool fo...
446KB Sizes 0 Downloads 0 Views