ROLE OF FETAL ECHOCARDIOGRAPHY IN

CONGENITAL HEART DISEASES

BY JAMEEL A. AL-ATA CONSULTANT AND ASSISTANT

PROFESSOR OF PEDIATRIC CARDIOLOGY

INTRODUCTION

Incidence of CHD is 6-8/1000 live births and about 1.5% in the fetus population.Nearly all types of postnatally diagnosed CHD types were diagnosed prenatally.The more complex in utero CHD the more diagnosed and the simpler can be missed in utero (ASD, mild AS, mild PS).Some CHD types are shown to evolve and progress in utero e.g Valvar AS.17-48% of in utero CHD is associated with chromosomal abnormalities (only 5-10% postnatally) and 20% with extracardiac malformations.

INTRODUCTION, CON’T;Fetal Echocardiography is an accurate diagnostic tool for CHD (85-90% sensitivity; 99% specificity) when using state of the art U/S technology and when pediatric cardiology/fetal medicine collaborates.

Routine obstetrical U/S is not a good screening test for CHD. It is both late (20-24 wks) and not comprehensive.

Indications include: DM, INFESTIONS, TERATOGENS ABN 4 CH VIEW, HX OF CHILD WITH CHD, CHROMOSOMAL ABN, EXT CARDIAC ABN, DEXTROCARDIA, SITUS INVERSUS, FETAL GROWTH RETARDATION AND FETAL ARRHYTHMIA.

Table 1: Sensitivity of ultrasound by type of anomaly in 4615 malformations

56100Total

187Cleft lip & palate

545Digestive system

8821Urinary tract

3723Muscoloskeletal

2821Cardiovascular

8816Central nervous system

SensitivityPrevalence (%)

of all anomaliesAnomaly

Table 4: Accuracy of prenatal diagnosis of congenital heart disease43

99.49299.786792120Todrus

---8369-Bromley

(1992)

9898.610081.391989Crawford

(1988)

--1005749-Benacerraf

(1987)

99.39699.7881092060Steward

(1987)

10010010010014266Copel

(1986)

99.694.599.887.5341200Allan

(1984)

Negative predictive value (%)

Positive predictive value (%)

Specificity

(%)

Sensitivity

(%)

n

CHD

n

screened

Author

(year)

Fig. 5: Apical four chamber view of the fetal heart (LV, left ventricle; RV, right ventricle; LA, left atrium; RA, right atrium; MB moderator band; PV, pulmonary veins; Ao, descending aorta; S, fetal spine)

IMPACT OF FETAL ECHOCARDIOGRAPHY

ON EPIDEMIOLOGY

Malformations due to pregnancy termination True incidence of CHD is 1.0% (0.2-0.4% higher than detected postnatally).

Up to 48% of in utero CHD is associated with chromosomal anomalies and 20% with extracardiac malformations.

Possible decreased prevalence of subsets of CHD associated with severe extracardiac malformations.

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In a recent study one hundred and forty-nine fetuses with CHD and normal karyotype were analyzed. Seventy-six fetuses had conotruncal anomalies. 22q11.2 deletion was present in 10 cases (6.7%), all of which had conotruncal anomalies (13.1%).

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Thymic hypoplasia or absence was suspected in 11 cases with conotruncal anomaly. Nine of these 11 had the deletion; two cases were false positive.

One fetus with a normal-sized thymus had deletion of 22q11.2 (sensitivity 90%, specificity 98.5%, positive predictive value 81.8%, and negative predictive value 99.2%).

ON FETAL & NEONATAL WELL-BEING

Timed delivery in tertiary care centers.

Decreased morbidity and perhaps better long term outcome of infants with semi lunar valves obstruction and/or ductal dependant lesions.

Intrauterine treatment (e.g. fetal arrhythmias).

Monitoring fetal well being during maternal trearment

ON MANAGEMENT

Better prognostication and counseling.

Pregnancy termination at the appropriate time.

Better understanding of the pathophysiology and evolution of CHD.

HOW TO GET A REAL IMPACT

Fetal echocardiographic screening at 11-14 weeks of gestation.Screening of both low risk and high risk pregnancies.Developing markers.Collaboration and the use of state of art U/S with Doppler, color flow Doppler and power Doppler…..etc.

Continuation;

Including the ventricular outflow tracts with the four chamber view in obstetrical U/S.

Training obstetrical technicians to do so.

Developing safe intra uterine interventional procedures.

CONCLUSION

Fetal echocardiography main impact is on incidence and appropriate prenatal, perinatal treatment.It is a demanding, yet, promising tool.Sequential studies are needed to track evolving lesions.Limitations include: operator level of expertise, technology, nature of CHD, number of collaborating centers, level of awareness and referrals……etc.

a family history of congenital heart disease an abnormal fetal heart rhythm fetal heart abnormalities detected during a routine pregnancy ultrasound scan abnormality of another major organ system insulin-dependent (type 1) diabetes mellitus exposure to some drugs in early pregnancy. For example, some anti-epileptic drugs can damage the developing heart. abnormal amniocentesis (AM'ne-o-sen-TE'sis). This is abnormal amniotic fluid in the woman's uterus.

                                                                

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Maternal Drug Exposure and Diseases

Women with seizure disorders taking anti-convulsantsWomen taking lithium for depressionWomen taking insulin for diabetesWomen who have phenylketonuriaWomen exposed to Rubella

Family History of Congenital Heart Disease

Previous child with CHD, new risk is 1 in 20 to 1 in 100Previous two children with CHD, new risk is 1 in 10 to 1 in 20Mother has CHD, new risk is as high as 1 in 5 to 1 in 20Father has CHD, new risk 1 in 30

Increased Maternal Risk for Down Syndrome and Other Chromosomal Defects

Chromosome abnormalities and CHD

Down syndromeTrisomy 18 and Trisomy 13Turner's syndromeCri du chat syndromeWolf-Hirshhorn syndromeDiGeorge syndrome (deletion 22q11)

Ultrasound -Identified Fetal Birth Defects of the Current Pregnancy

Other Rare Genetic Diseases

Marfan syndromeSmith-Lemli-Opitz syndromeEllis-van CreveldHolt-Oram syndromeNoonan syndromeMucopolysaccharidosesGoldenhar syndrome (hemifacial microsomia)William's syndromeVACTERL association (tracheal and esophageal malformations associated with vertebral, anorectal, cardiac, renal, radial, and limb abnormalities).