Fetal intracardiac echogenic focus in pregnants underwent amniocentesis

Objective

It was aimed to define the frequency of intracardiac echogenic focuses in the fetuses with normal karyotype and with Down syndrome in our study population.

Methods

The intracardiac echogenic focuses obtained from second line USG are tested in the fetuses whom made amniocentesis and karyotyping because of the reasons like old maternal age, increased risks with in scanning tests, structural anomalies in the USG and family history.

Results

The 1350 fetuses whom made karyotype analysis; 1293 of the fetuses obtained with normal karyotype. Thirty-two of the fetuses diagnosed with Down syndrome, 10 of fetuses with trisomy 18, 6 of them with trisomy 13, 5 of them with Turner syndrome and 4 of fetuses are obtained with other aneuploidies. The frequency of fetal intracardiac echogenic focuses was found %2.4 with in normal fetuses,%12.5 fetuses with in Down syndrome, %0 of fetuses with trisomy 18, %16.6 of fetuses with trisomy 13, %0 of fetuses with Turner syndrome and 4 fetuses having other karyotypes. The frequency of echogenic focuses was found higher significantly in fetuses with Down syndrome than the fetuses who have normal karyotype (p<0.05).

Conclusion

Although the frequency of fetal intracardiac echogenic focuses are seen to be higher in fetuses with Down syndrome by comparison with the fetuses which have normal karyotype, more studies must be performed to accept it as a marker.

Keywords

Fetal intracardiac echogenic focus, Down syndrome, caryotype analysis

Introduction

Frequency of chromosomal aberrations in newborn children is approximately 1 in 165.[1] Chromosomal aberrations increase as the mother’s age increases. However, because only pregnant women over 35 are checked with screening tests, 80% of the fetal aneuploidies may be overlooked.[1,2] The evaluation of obstetric ultrasound findings in aneuploid diagnosis is used to detect risky pregnancies. The most common findings known as aneuploidy markers are echogenic intracardiac focus, echogenic bowel, shortness of long bones and renal pyelectasis. The detection of these soft markers increases the risk of trisomy.[21]
In this study, echogenic intracardiac focuses that were detected in normal fetuses and those with Down syndrome after carrying out amniocentesis and karyotyping for different reasons, have been examined and discussed.

Methods

It has been evaluated the cases which had invasive tests with the indications of advanced maternal age, increasing risk in screening tests, childbirth that has chromosomal aberrations before, family history and ultrasonographic indications such as structural anomalies and cases that were performed amniocentesis in the last 1.5 years in our hospital. Before the amniocentesis, level 2 ultrasound scan was performed to all pregnant women in their 16th to 20th week of pregnancy by the specialist physicians of our hospital. Echogenic intracardiac focuses and other pathologies that were detected by ultrasonographic examination were added into the computer records. The cases, whose karyotyping analysis was fully obtained after carrying out amniosynthesis, were taken into the scope of the study. The frequency rate of the fetal echogenic intracardiac focuses which are detected in fetuses with mainly Down syndrome and other chromosomal aberrations are compared with the fetuses with normal karyotype. The cases that karyotype analysis is not reached was excluded.
Chi-Square test was used in statistical evaluations.

Results

Normal chromosome structure was detected in 1,293 cases out of 1,350 after karyotyping analysis in our working group. Trisomy 21 was diagnosed in 32 cases (2.4 %). Echogenic intracardiac focus was detected in 39 out of 1,293 cases with normal karyotype by ultrasonographic scan. Echogenic intracardiac focus was detected in 4 % of the 32 cases with Down syndrome (12.5%). When the echogenic focus rates in fetuses with normal karyotype and Down syndrome are compared, a statistically significant difference was reported (p<0.05). Trisomy 18 was diagnosed in 10 cases. Echogenic intracardiac focus was not monitored in these cases. Trisomy 13 was diagnosed in 6 cases. Echogenic intracardiac focus was monitored in one of these cases (16.6%). Echogenic focus was not monitored in 5 Turner syndrome, 1 Klinefelter syndrome and 3 aneuploidy cases (Table 1).
Chromosomal aberration rate in total 44 fetuses, whose echogenic focuses are monitored, are calculated as 11.4 % (5 fetuses).
 

Discussion

In general, echogenic intracardiac focus is monitored in 2-5% of the fetuses.[3–5] Focus is usually monitored in the left ventricular, but it may occur in the right ventricular or in both. The focuses may be solitary or more and 95% of them vanish in the third trimester.[6]
While some authors claim that echogenic focus is the marker of Down syndrome.[3,7,8] the others haven’t found a relationship between the focus and Down syndrome.[4,7,9]
Brown et al. showed that the finding of an echogenic intracardiac focus at ultrasosonagrafy correlates with mineralization within a papillary muscle of the fetal heart.[10] Bromley et al. in 1995 reported a 4.9% incidence of EIF (echogenic intracardiac focus) among 1,334 fetuses studied. They also found that extremly high rate of 18% of fetuses with trisomy 21 had an EIF and that sonographic identification of an EIF had a fourfold increase risk of trisomy 21.[3] Petriskovsky et al. reported a 3.6% incidence of EIF in 1,139 patients, all of whom had a normal karyotype. The authors reported that they didn’t detect any correlation between echogenic focus and adverse perinatal outcome.[6,11] EIF rate in our study was 2.4% among 1,293 fetuses with a normal karyotype at a similar rate in these studies.
Bromley et al. reported a 4.8% incidence of aneuploidy in 290 fetuses that had an EIF.[12] Chromosomal aberration rate in our study was 11.4% among 44 fetuses with EIF.
A meta-analysis conducted in 2001 by Smith-Bindman and friends determined that, (a total of 56 studies describing 1,930 fetuses with Down syndrome and 130,365 unaffected fetuses were included) when ultrasonographic markers were observed with structural malformations to detect Down syndrome, sensitivity for each one was 16% and when structural malformations were not observed, this rate was only 1%. Of the 5 studies in the meta-analysis that specifically looked at EIF, there were a total of 5,948 patients, 7.3% of whom had EIF. Authors suggested that in existance of intracardiac echogenic focus,if amniocentesis is offered in order to final exact diagnose of Down syndrome fetus,it is come up with that 2 in low risk group patient and 1 in high risk group of patient is going to be lost connection with amniocentesis complications.[13] In our study, there were a total of 32 Down syndrome cases, 12.5 % of whom had EIF, which was significantly higher than fetuses with a normal karyotype (2.4%). In trisomy 13 cases, this rate was extremly high rate of 16.6 % , but this marker was not observed in 10 cases with Trisomy 18. Roberts et al. reported a 16% incidence of EIF among Down syndrome cases and %2 incidence of EIF in the normal population.[5] Similarly, Bromley et al. detected a 18% incidence of EIF among Down syndrome cases and a 5% incidence of EIF among normal fetuses.[3]
Winter et al. evaluated 3,303 fetuses with an ultrasonograpic scan and karyotype analysis and determined that EIF was found in 4.6% of normal fetuses and 30% of fetuses with trisomy 21. The authors concluded that, an isolated echogenic intracardiac focus was associated with a 4.8 fold increase in relative risk for trisomy 21.[14]
Nyberg et al. evaluated the ultrasound findings in 186 fetuses with Down syndrome and 8.728 controls and they reported that EIF was the most common marker found among affected fetuses after exclusion of major anomalies (7.1%).[15] Rebarber et al. reported a 14.8% incidence of intracardiac fetus among 148 Japanese patients, whose maternal age was 30.7 on the average, but they didn’t find any abnormal karyotypes.[16] These data are contradicted with idea of Bromley and Winter which says intracardiak focus trizomi 21 increases. This contradiction bring question mind; can we reach different result in ultrasonographic analysis in different societies or not.
Coco et al. evaluated 12,672 patients and detected 479 cases of echogenic focus; 90.4% of which were isolated. Eleven patients had fetuses with Down syndrome (%0.09), but only 3 of these had an echogenic focus. Up to statistical analysis; although the fetuses with an echogenic intracardiac focus have an increased risk of aneuploidy, amniocentesis need not be offered to patients who are otherwise at low risk and have an isolated echogenic intracardiac focus.[17] In another study that evaluated 62,111 patients and and found 2,223 echogenic intracardiac focus, Down syndrome was detected in 218 fetuses (0.4%). It is emphasized that the detection of isolated echogenic focus doesn’t increase the risk of trisomy 21 for patients whose maternal age is younger than 35 years old.[18] In a study where intracardiac echogenic focus and multple echogenic focus are compared in terms of aneuploid risk, 6 (8.5%) patients with Down syndrome is found in 71 fetuses with multipl echogenic focus and 1 (0.6%) patient with Down syndrome is found in 171 fetuses with single echogenic focus.[19]
 

Conclusion

Echogenic intracardiac focus is monitored in Down syndrome cases more than normal karyotype cases, however more research should be done in order to detect EIF as the marker of Down syndrome.

References

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	File/Dsecription
	Table 1. Karyotype and echogenic intracardiac focus results of 1,350 cases .