The detection of isolated fetal heart abnormalities is still low compared to other fetal abnormalities. The Eurocat data report, which was performed between 2008 and 2012 in 19 countries, shows that out of the top 14 most detected fetal abnormalities without chromosomal associations, only two are cardiac ones. The transposition of the great fetal arteries was intrauterinelly recognized only in 44.8% of the cases, while hypoplastic left heart syndrome, in 73.8% of the cases(1).
In recent years, there is a trend towards performing fetal cardiac ultrasonography screening in the first trimester. Literature data can be found regarding this aspect since the the ’90s(2,3). In the last 10 years, various articles have been published, highlighting that ultrasound screening, performed on large groups of pregnant women, was carried out successfully in almost 100% of the cases:
Persico (2011) study completed at 11-13 weeks with cardiac screening performed by specially trained obstetricians. In only 19 out of 886 cases (2.1%), ultrasound sections were not considered appropriate for assessing normality or abnormality(4).
Ebrashy et al. (2010) highlighted that transvaginal sonography, compared to the transabdominal one, increases the rate of visualizing the fetal organs more appropriately between 11-13 weeks, but found no differences for the fetal heart (61.4% vs. 62.7%, P=0.414)(5).
Lombardi et al. (2007). The time required for the evaluation of the normality of the images of the fetal heart was below 10 minutes in 517/608 (85%) of cases and longer in 85/608 (14%) of cases. Only in 1% of cases a new ultrasound was required after 2 weeks(6).
In a study conducted at a gestational age ranging from 11 weeks and 13 weeks and 6 days on a total of 1084 patients, Marcin Wiechec and collaborators have detected 35 cases (3.22%) of cardiac anomalies, out of which 16 were aneuploidies. The best technique for detecting these anomalies is the use of color flow Doppler on sections with a four-chamber view plus three-vessel and trachea view. Using this technique, the authors obtained a 88.57% sensitivity, 100% specificity, 100% positive predictive value, 99.62% negative predictive value and 99.63% accuracy in the diagnosis of cardiac abnormalities in the first trimester(7).
Basically, first trimester cardiac ultrasound screening is important for detecting severe defects and not the exact diagnosis. It is based on: site, size, the position of the heart in the chest, rhythm, sections with four-chamber view, left ventricular outflow tract, plus Doppler with three-vessel and trachea view “pattern” or anything unusual that can be noticed. However, until now there is a single international screening ultrasound guide for the first trimester(8), with the requirement to evaluate only a regular fetal cardiac activity and the heart in four chamber section, with symmetrical chambers.
The practical problems arising after a suspected cardiac abnormality in the first trimester of pregnancy are: uncertain diagnosis difficult to be counseled by a paediatric cardiologist, the patient’s panic and often the decision to interrupt the pregnancy before a full diagnosis and prognosis are established. The suspicion of this anomaly requires serious reassessments within an interval of 1 week, especially at 15 and 16 weeks, best performed with a specialized paediatric cardiologist.
The first guide on the screening of fetal heart in the second trimester was developed 10 years ago by the International Society of Ultrasound in Obstetrics & Gynecology (ISOUG)(9). This guide was “upgraded” in 2011(10) and 2013(11). In 2014, the Romanian Society of Ultrasound in Obstetrics and Gynecology (SROUG) adopted this guide, based on the principles of ISOUG(12).
The practical problems arising after a suspected cardiac abnormality in the second trimester of pregnancy are the following: it requires counseling from a specialized paediatric cardiologist, referral to a tertiary center for giving birth, establishing whether the malformative pathology can be resolved surgically in Romania, in utero worsening of the pathology - depending on the prognosis and gestational age, the possibility of medical abortion based on the prognosis of the malformation (i.e., severe hypoplastic left heart syndrome).
Material and methods
In the centre from Târgu-Mureş, which comprises an Institute of Cardiovascular Diseases and Transplantation, situated in the same building as the Clinic of Obstetrics and Gynecology and the Neonatal Intensive Care Unit, involved in the surgical correction of congenital cardiac abnormalities, a program of ultrasonographic screening courses for the detection of fetal cardiac malformations and for fetal echocardiography was initiated since 2008.
Organized almost every year, lectures on this subject, held by paediatric cardiologists and obstetricians, have managed to bring along over 600 participants. In parallel, casuistry with suspected fetal cardiac abnormalities underwent an evident ascent in our centre, which is considered to be a reference centre. Thus, the casuistry of the centre from Târgu-Mureş, evaluated by an obstetrician and a specialized paediatric cardiologist - between 28th February 2007 and 10th November 2015 - consisted of 363 cases with abnormal fetal heart suspicions, out of which:
99 had a normal heart;
5 cases were plurimalformative without cardiac defects;
23 cases had pathological arrhythmias;
236 cases had structural cardiac abnormalities.
Pregnant women with malformed fetuses received prognostic advice from a cardiologist and a cardiovascular surgeon.
The increased frequency of detecting cardiac abnormalities can be observed in the development of cases sent to the centre from Târgu-Mureş, from 4 patients in 2007 reaching 93 patients in the first 10 months of 2015.
The change of reference diagnosis is relevant for the increase in the screening and diagnosis level of the obstetricians in this country. Only cases of heart rhythm disorders and plurimalformed fetuses were sent to the centre from Târgu-Mureş in 2007. Between 2008 and 2011 anomalies that were visible on the four-chamber view were sent to our centre. Another relevant aspect for the increased quality in detecting fetal chromosomal abnormalities in our country is the evolution of atrioventricular septal defect detection that accompanies Down syndrome. These decreased from 10 in 2011 to 3 cases in 2015, and the fineness of the diagnosis of abnormality was shifted to detect incomplete forms of atrioventricular septal defect. Since 2010, more conotruncal abnormalities and coarctation of the aorta suspicions were sent for a second opinion.
If in 2011 identifying the screening of persistent left superior vena cava was made only in complex malformations, in 2015 isolated forms of these anomalies were detected at screening. Also, in 2015 and 2016 rare malformations were detected, requiring experience and specific knowledge: total anomalous pulmonary venous connection, corrected transposition of the great fetal vessels, absence of the pulmonary valve. Due to changes in first trimester ultrasonography, we recorded the first fetal cardiac abnormalities detected on screening at 11-13 weeks, a total of 5 cases between 2015-2016. The gestational age of the patients sent to our centre with suspected cardiac abnormalities decreased over the past few years. Although between 2010-2013 over 80% of the cases had been suspected of cardiac abnormality after 24 weeks of gestation, in 2015 over 80% of the cases were sent before 24 weeks. On the other hand, since there is a degree of association between fetal cardiac abnormalities and other abnormalities, some anomalies remain undiagnosed.
Casuistry changes were recorded regarding this aspect as well. While anomalies associated with newborns in 2007 were plurimalformative, in 2016 cases with abnormal cloaca, faulty soft palate, which can hardly be identified in utero, were detected.
Unfortunately, there is no unique way of reporting cardiac abnormalities and other birth defects in newborns, as there is no fetal universal screening granted for pregnant women in our country. These things make it difficult to assess the impact of the aforementioned figures, regarding the total number of real cases of newborns with heart anomalies in our country.
The detection age for cardiac abnormalities decreased in our country as well. The detection of cardiac abnormalities in the first trimester is possible in our country. There is an increasing trend towards detecting fetal cardiac abnormalities in Romania, evidenced by the increase in the number of cases sent to our centre.
The gestational age at which patients receive advice from a cardiologist - cardiac surgeon, is still too advanced, at a number of important cardiac abnormalities detected in utero. The courses and the continuous training of obstetricians, who are directly involved in the ultrasonographic screening for the detection of fetal cardiac malformations, led to obvious improvement of the results. n