Article Diagnosis of Congenital Cardiac Defects Between 11 and 14 Weeks Gestation in High-Risk Patients Zeev Weiner, MD, Abraham Lorber, MD, Eliezer Shalev, MD Objective. To examine the feasibility of diagnosing congenital cardiac defects between 11 and 14 weeks gestation in a high-risk population. Methods. Fetal echocardiography was first offered at 11 to 14 weeks gestation to all patients at risk for congenital heart defects. Echocardiography performed at 11 to 14 weeks with normal results was repeated at 14 to 16 and 20 to 24 weeks. Final diagnoses of cardiac anomalies that had been observed at 11 to 14 weeks were established at 14 to 16 weeks or later. Fetal echocardiography performed at 14 to 16 weeks with normal results was repeated at 20 to 24 weeks. Ascertainment of cardiac anomalies was obtained by postnatal echocardiography or pathologic examination of the fetal heart after termination of pregnancy. Most of the examinations were performed transvaginally until 16 weeks. The transabdominal approach was used at this stage only when patients refused the transvaginal examination or because of technical difficulties. Three hundred ninetytwo fetal echocardiographic examinations were performed between 11 and 14 weeks gestation; 438 examinations were performed between 14 and 16 weeks; and 777 examinations were performed between 20 and 24 weeks. The major indications for fetal echocardiography at 11 to 14 weeks were maternal diabetes and previous pregnancy with congenital heart defects. Results. Six of 7 major fetal cardiac anomalies were detected. The only major cardiac anomaly that was not detected between 11 and 14 weeks was correctly diagnosed at 22 weeks. Only 1 of 5 minor fetal cardiac anomalies was detected between 11 and 14 weeks. Another 2 minor fetal cardiac anomalies were detected at 23 weeks. Four incorrect diagnoses of minor cardiac anomalies were excluded on repeated fetal echocardiography between 20 and 24 weeks. Conclusions. The initial attempt to diagnose congenital heart defects should be offered at 11 to 14 weeks gestation. Key words: fetal echocardiography; first trimester; congenital heart defects. Received April 25, 2001, from the Department of Obstetrics and Gynecology, Haemek Medical Center, Afula, Israel (Z.W., E.S.); and Department of Pediatric Cardiology, Rambam Medical Center, Haifa, Israel (A.L.). Revision requested June 12, 2001. Revised manuscript accepted for publication September 4, 2001. Address correspondence and reprint requests to Zeev Weiner, MD, Director of Perinatology, Department of Obstetrics and Gynecology, Haemek Medical Center, Afula 18101, Israel. Prenatal diagnosis of congenital cardiac defects in a low-risk population is limited. 1 Previous studies have suggested that the prenatal screening test for congenital cardiac defects using the 4-chamber view does not suffice. 1 4 However, diagnosis of congenital cardiac defects improves when complete fetal echocardiography is performed by skilled sonographers. 5 It is therefore important to define and to detect high-risk groups for congenital cardiac defects and to provide adequate services for fetal echocardiography. The current generation of sonographic equipment has improved the image quality of the fetus during early stages of pregnancy. Preliminary studies have reported 2002 by the American Institute of Ultrasound in Medicine J Ultrasound Med 21:23 29, 2002 0278-4297/02/$3.50
Congenital Cardiac Defects in High-Risk Patients the feasibility of late-first-trimester (11 14 weeks gestation) fetal echocardiography. 6 8 Since January 1995 we have offered early fetal echocardiography between 11 and 14 weeks gestation to all high-risk groups of women. In this study, we report 4 years experience with this approach to fetal echocardiography. Materials and Methods All high-risk patients undergoing fetal echocardiography between January 1995 and March 1999 were included in the study. Indications for fetal echocardiography included (1) women with pregestational diabetes, (2) pregnant women who had previous pregnancies with congenital heart defects, (3) pregnant women with congenital heart defects, (4) pregnant women who were exposed to a known teratogen causing congenital heart defects (e.g., hydantoin), (5) fetal arrhythmia, and (6) questionable findings on fetal scanning. This major group of patients had routine transvaginal (14 16 weeks gestation) or transabdominal (20 24 weeks gestation) fetal scanning at different affiliated hospitals or private institutes. Patients were referred for fetal echocardiography when fetal cardiac anomalies were suspected. The first fetal echocardiographic examination was offered to all high-risk patients at 11 to 14 weeks gestation. When the indication for fetal echocardiography did not allow early examination or when for other reasons the patients were referred later than 11 to 14 weeks gestation, they were scheduled for fetal echocardiography at 14 to 16 or at 20 to 24 weeks gestation. We therefore divided our patients undergoing fetal echocardiography into 3 groups: group 1, fetal echocardiography that was initially performed at 11 to 14 weeks gestation; group 2, fetal echocardiography that was initially performed at 14 to 16 weeks gestation; and group 3, fetal echocardiography that was initially performed at 20 to 24 weeks gestation. Fetal echocardiographic examinations performed at 11 to 14 weeks gestation with normal results were repeated at 14 to 16 and 20 to 24 weeks gestation. Final diagnoses of cardiac anomalies observed at 11 to 14 weeks gestation were established at 14 to 16 weeks gestation or later. Echocardiographic examinations performed at 14 to 16 weeks gestation with normal results were repeated at 20 to 24 weeks gestation. Ascertainment of cardiac anomalies was obtained by postnatal echocardiography or by pathologic examination of the fetal heart after termination of pregnancy. Fetal echocardiographic examinations were performed in the Ultrasound Unit of the Department of Obstetrics and Gynecology at Rambam Medical Center (until August 1998) and the Ultrasound Unit of the Department of Obstetrics and Gynecology at Haemek Medical Center (from September 1998). The sonography equipment used was an Acuson 128 XP10 system (Acuson Corporation, Mountain View, CA) with a 6.5-MHz transducer for transvaginal examinations and a 5-MHz transducer for transabdominal examinations. Most of the examinations were performed transvaginally until 16 weeks gestation. The transabdominal approach was used at this stage only when patients refused the transvaginal examinations or because of technical difficulties. Fetal echocardiography included visualization of the 4-chamber view, long axis of the aorta, short axis of the great vessels, aortic and ductal arch, inferior and superior vena cava connections, and vena pulmonalis connections. Doppler studies of the atrioventricular, aortic, and pulmonic valves were also performed. To improve the visualization of the septal integrity and to show the intracardiac and extracardiac blood flow, color and power Doppler sonography were routinely used in all fetal echocardiography (Fig. 1). The minimal requirement for complete fetal echocardiography at 11 to 14 weeks gestation included visualization of the 4-chamber view, the long axis of aorta, the short axis of the great vessels, and the aortic arch. Results Three hundred ninety-two fetal echocardiographic examinations were performed between 11 and 14 weeks gestation; 438 examinations were performed between 14 and 16 weeks gestation; and 777 examinations were performed between 20 and 24 weeks gestation. The indications for fetal echocardiography at different stages of pregnancy are presented in Table 1. The major indications for fetal echocardiography at 11 to 14 weeks gestation were maternal diabetes and previous pregnancy with congenital heart defects. 24 J Ultrasound Med 21:23 29, 2002
Weiner et al As shown in Table 2, only a small number of examinations were performed between 11 and 12 weeks gestation. Most of the early examinations were performed between 12 and 14 weeks gestation, and the success rate of performing complete fetal echocardiography at this stage was very high. Table 3 summarizes the fetal cardiac anomalies detected by fetal echocardiography performed between 11 and 14 weeks gestation. Six of 7 major fetal cardiac anomalies were detected, including hypoplastic left (2 cases) and right atria and ventricles, transposition of the great vessels, trunkus arteriosus, and atrioventricular canal. The only major cardiac anomaly that was not detected between 11 and 14 weeks gestation was correctly diagnosed later at 22 weeks gestation (tetralogy of Fallot). Only 1 of 5 minor fetal cardiac anomalies was detected between 11 and 14 weeks gestation (ventricular septal defect). Another 2 minor fetal cardiac anomalies (ventricular septal defect) were detected later at 23 weeks gestation. Another 3 minor fetal cardiac anomalies (ventricular and atrial septal defect) were diagnosed only after birth. There were also 4 incorrect diagnoses of minor cardiac anomalies that were excluded on repeated fetal echocardiography between 20 and 24 weeks gestation. Figures 2 and 3 show a hypoplastic right atrium and ventricle with a large ventricular septal defect detected at 13 weeks gestation. Tables 4 and 5 summarize all fetal cardiac anomalies detected or undetected between 14 and 16 and 20 and 24 weeks gestation, respectively. Discussion Because the birth prevalence of congenital cardiac defects is almost 1% or even greater in highrisk groups, fetal echocardiography has a major role in prenatal diagnosis of congenital birth defects. Prenatal diagnosis of congenital cardiac Figure 1. Aortic arch (blue) and inferior vena cava (red) clearly shown on color Doppler imaging at 13 weeks gestation. defects has several purposes. First, patients can be advised about prognosis and possible options for treatment and can be referred to experienced teams. It is therefore important to make a correct diagnosis of the nature of the cardiac defects (particularly in cases of complex cardiac defects). Second, because there is a strong association between cardiac defects and chromosomal aberrations, amniocentesis can be offered when congenital cardiac defects are diagnosed. Third, patients can choose termination of pregnancy when severe congenital cardiac defects are diagnosed. The importance of early diagnosis is evident considering the advantages of prenatal diagnosis of congenital cardiac defects. The feasibility of prenatal diagnosis of congenital heart defects during the late first trimester of pregnancy has been discussed previously. 6 8 Dolkart and Reimers 6 described the rate of success in documenting cardiac anatomy between 10 and 15 weeks gestation. The 4-chamber view was observed in 90% of fetuses at 12 weeks gestation, but the other views were not imaged as easily at this stage. The diagnostic capacity of fetal echocardiography when using transvaginal sonography between 11 and 14 weeks also has been described by D Amelio et al. 7 In a large Table 1. Indications for Fetal Echocardiography at the Different Stages of Pregnancy Indication 11 14 wk (n = 392) 14 16 wk (n = 438) 20 24 wk (n = 777) Questionable findings on fetal scanning 0 70 209 Diabetes 116 120 180 Maternal CHD 58 111 192 Previous pregnancy with CHD 103 104 153 Exposure to teratogens 15 24 31 Fetal arrhythmia 0 9 12 J Ultrasound Med 21:23 29, 2002 25
Congenital Cardiac Defects in High-Risk Patients Table 2. Success Rate in Performing Complete Fetal Echocardiography Between 11 and 14 Weeks Gestation Successful Complete Fetal Gestation, wk Examinations Echocardiography, n (%) 11 12 45 40 (88) 12 13 191 185 (97) 13 14 156 154 (99) study, Yagel et al 8 detected 64% of the cardiac malformations at 13 to 16 weeks gestation. More cardiac malformations were detected at 20 to 22 weeks gestation and during the third trimester of pregnancy. The authors concluded that although most fetal cardiac anomalies are detectable early in gestation, some may evolve in utero at different stages of pregnancy. Achiron et al 9 described the results of fetal echocardiography performed between 13 and 15 weeks gestation in a low-risk population. Fetal heart examination was completed in 98% of the cases, and the 4-chamber view was obtained in 100%. Three major congenital cardiac defects were diagnosed, but 3 other congenital cardiac defects were not diagnosed at this stage. Other case reports described first-trimester diagnosis of congenital cardiac defects with the use of M- mode and Doppler echocardiography at as early as 10 weeks gestation. Baschat et al 10 described first-trimester diagnosis of congenital heart defects by detection of a fetal heart block on M- mode and Doppler echocardiography. Borrell et al 11 described reversed end-diastolic velocity in the umbilical artery at 10 weeks gestation as the first sign of hypoplasia in the right atrium and ventricle. Here we have presented the results of a prospective study in which fetal echocardiography was performed between 11 and 14 weeks gestation in a high-risk group of patients. The success rate of complete fetal echocardiography after 11 weeks gestation was very high. According to our results, major congenital cardiac defects can be accurately diagnosed between 11 and 14 weeks gestation. Minor defects cannot be easily diagnosed during pregnancy, especially at 11 to 14 weeks gestation. Therefore, when major congenital cardiac defects are diagnosed at this stage, patients can be advised about the prognosis and can even choose to terminate pregnancy when the diagnosis is clear (e.g., a hypoplastic ventricle). However, definite conclusions cannot be obtained when the results of the examinations are normal or when minor congenital cardiac defects are diagnosed between 11 and 14 weeks gestation. Table 3. Fetal Cardiac Anomalies Between 11 and 14 Weeks Gestation Anomaly Gestation, wk Indication Correct diagnosis Hypoplastic left atrium and ventricle 11.4 Maternal CHD Hypoplastic left atrium and ventricle 12.2 Previous pregnancy with CHD Hypoplastic right atrium and ventricle 13.0 Diabetes Transposition of the great vessels 13.2 Diabetes Trunkus arteriosus 12.1 Previous pregnancy with CHD Atrioventricular canal 2.4 Previous pregnancy with CHD Ventricular septal defect 13.2 Maternal CHD Incorrect diagnosis Ventricular septal defect 11.5 Diabetes Ventricular septal defect 12.5 Maternal CHD Ventricular septal defect 13.2 Maternal CHD Coarctation of aorta 12.2 Previous pregnancy with CHD Undetected Tetralogy of Fallot 12.2 Diabetes* Ventricular septal defect 12.3 Diabetes* Ventricular septal defect 11.5 Maternal CHD Ventricular septal defect 12.5 Maternal CHD* Atrial septal defect 13.2 Previous pregnancy with CHD Atrial and ventricular septal defect 12.6 Diabetes *Detected between 20 and 24 weeks gestation 26 J Ultrasound Med 21:23 29, 2002
Weiner et al Figure 2. Hypoplastic right heart with large ventricular septal defect (arrow) at 13 weeks gestation. Figure 3. Same case as in Figure 2 shown on color flow imaging. Only blood flow from the left atrium into the left ventricle is shown. No blood flow from the right atrium into the right hypoplastic ventricle is shown. The flow into the right hypoplastic ventricle probably passes through the large ventricular septal defect. As in most of the other cases, color flow imaging was not essential for diagnosing congenital heart defects but assisted in defining the different components of the cardiac anomalies. Table 4. Fetal Cardiac Anomalies Between 14 and 16 Weeks Gestation Anomaly Gestation, wk Indication Correct diagnosis Hypoplastic left atrium and ventricle 14.5 Maternal CHD Hypoplastic left atrium and ventricle 15.0 Questionable findings on fetal scanning Hypoplastic left atrium and ventricle 15.5 Previous pregnancy with CHD Atrioventricular canal 15.1 Questionable findings on fetal scanning Atrioventricular canal 15.6 Previous pregnancy with CHD Ventricular septal defect 14.5 Questionable findings on fetal scanning Ventricular and atrial septal defect 15.3 Diabetes Trunkus arteriosus 15.0 Questionable findings on fetal scanning Tetralogy of Fallot 14.4 Maternal CHD Tetralogy of Fallot 15.3 Questionable findings on fetal scanning Transposition of the great vessels 15.4 Diabetes Aortic stenosis 16.0 Maternal CHD Coarctation of aorta 15.3 Questionable findings on fetal scanning Interruption of the inferior vena cava 14.3 Questionable findings on fetal scanning Incorrect diagnosis Ventricular septal defect 15.3 Questionable findings on fetal scanning Ventricular septal defect 15.5 Maternal CHD Coarctation of aorta 16.0 Diabetes Undetected Ventricular septal defect 15.2 Diabetes* Ventricular septal defect 15.5 Diabetes Atrial septal defect 16.0 Previous pregnancy with CHD Pulmonic stenosis 15.0 Maternal CHD* *Detected between 20 and 24 weeks gestation J Ultrasound Med 21:23 29, 2002 27
Congenital Cardiac Defects in High-Risk Patients Table 5. Fetal Cardiac Anomalies Between 20 and 24 Weeks Gestation Anomaly Gestation, wk Indication Correct diagnosis Hypoplastic left atrium and ventricle 22.5 Questionable findings on fetal scanning Hypoplastic left atrium and ventricle 20.6 Questionable findings on fetal scanning Atrioventricular canal 22.1 Questionable findings on fetal scanning Atrioventricular canal 23.6 Previous pregnancy with CHD Double-outlet right ventricle 20.5 Questionable findings on fetal scanning Transposition of the great vessels 22.6 Questionable findings on fetal scanning Transposition of the great vessels 23.3 Questionable findings on fetal scanning Tetralogy of Fallot 21.0 Maternal CHD Pulmonic stenosis with hypoplastic right ventricle 24.0 Questionable findings on fetal scanning Aortic stenosis 21.2 Previous pregnancy with CHD Ventricular septal defect 23.5 Questionable findings on fetal scanning Ventricular septal defect 23.3 Diabetes Ventricular septal defect 21.3 Diabetes Coarctation of aorta 22.5 Previous pregnancy with CHD Vascular ring 23.0 Questionable findings on fetal scanning Incorrect diagnosis Ventricular septal defect 22.3 Questionable findings on fetal scanning Coarctation of aorta 23.0 Questionable findings on fetal scanning Undetected Ventricular septal defect 21.2 Diabetes Atrial septal defect 23.4 Maternal CHD Aortic stenosis 22.0 Questionable findings on fetal scanning Although we offered fetal echocardiography to all high-risk patients at 11 to 14 weeks gestation, most of the initial scans were performed later. Unfortunately, many patients are not referred for fetal echocardiography at 11 to 14 weeks gestation. For example, one of the major indications for fetal echocardiography is a questionable fetal heart abnormality observed by a sonographer who is not experienced in fetal echocardiography. We do not expect that patients will be referred for fetal echocardiography for this indication before 14 weeks gestation. However, although there are limitations in performing early fetal echocardiography for all high-risk patients, the initial attempt to diagnose congenital heart defects should be offered at 11 to 14 weeks gestation. References 1. Buskens E, Grobee DE, Frohn-Mulder IME, et al. Efficacy of routine fetal ultrasound screening for congenital heart disease in normal pregnancy. Circulation 1996; 94:67 72. 2. Luck CA. Value of routine ultrasound screening at 19 weeks: a 4 year study of 8849 deliveries. BMJ 1992; 304:1474 1478. 3. Rosendahl H, Kivenen S. Antenatal detection of congenital malformations by routine ultrasonography. Obstet Gynecol 1989; 73:947 951. 4. Tegnander E, Eik-Nes SH, Johansen OJ, Linker DT. Prenatal detection of heart defects at the routine fetal examination at 18 weeks in a non-selected population. Ultrasound Obstet Gynecol 1995; 5:371 380. 5. Achiron R, Glaser J, Gelenter I, Hegesh J, Yagel S. Extended fetal echocardiography examination for detecting cardiac malformations in low risk pregnancies. BMJ 1992; 304:671 674. 6. Dolkart LA, Reimers FT. Transvaginal fetal echocardiography in early pregnancy: normative data. Am J Obstet Gynecol 1991; 165:688 691. 7. D Amelio R, Giorlandino C, Masala L, et al. Fetal echocardiography using transvaginal and transabdominal probes during the first period of pregnancy: a comparative study. Prenat Diagn 1991; 11:69 75. 8. Yagel S, Weissman A, Rotstein Z, et al. Congenital heart defects: natural course and in utero development. Circulation 1997; 96:550 555. 28 J Ultrasound Med 21:23 29, 2002
Weiner et al 9. Achiron R, Rotstein Z, Lipitz S, Mashiach S, Hegesh J. First-trimester diagnosis of fetal congenital heart disease by transvaginal ultrasonography. Obstet Gynecol 1994; 84:69 72. 10. Baschat AA, Gembruch U, Knopfle G, Hansman M. First-trimester fetal heart block: a marker for cardiac anomaly. Ultrasound Obstet Gynecol 1999; 14:311 314. 11. Borrell A, Costa D, Martinez JM, et al. Reversed end-diastolic umbilical flow in a first-trimester fetus with congenital heart disease. Prenat Diagn 1998; 18:1001 1005. J Ultrasound Med 21:23 29, 2002 29