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Biomedical subjects

I C Huggon

Publications and source records attributed to I C Huggon.

At least 19 recordsLinked to original sources

Turner's syndrome in fetal life.

OBJECTIVE: To compare the incidence and type of heart disease found in association with 45X karyotype in fetal life with postnatal life and to examine the outcome after fetal diagnosis. METHODS: Fifty-three fetuses with a 45X karyotype were examined echocardiographically over a 4-year period between 1999 and 2002. Of these, 47 were referred because of increased nuchal translucency (NT). RESULTS: A cardiac abnormality was detected in 33/53 (62.2%) fetuses. The most common diagnosis was coarctation of the aorta in 24/53 (45.3%) fetuses, followed by the hypoplastic left heart syndrome (HLHS) in 7/53 (13.2%) fetuses. The mean NT was significantly higher in fetuses with a heart defect than in those with normal echocardiography. Termination of pregnancy was carried out in 45/53 (84.9%) fetuses and intrauterine death occurred in six cases. Two of four fetuses with a mosaic karyotype are currently alive. CONCLUSION: Turner's syndrome is associated with a higher incidence of heart defects detected prenatally when compared to postnatal reports. The commonest associated heart defects detected prenatally are HLHS and coarctation of the aorta, in contrast to postnatal life where a bicuspid aortic valve is the most common diagnosis. The typical intrauterine presentation of Turner's syndrome with a markedly increased NT or with hydrops and with a typical 45X karyotype has an extremely poor prognosis for intrauterine survival.

Aortic Coarctation↗

Tricuspid regurgitation in the diagnosis of chromosomal anomalies in the fetus at 11-14 weeks of gestation.

OBJECTIVE: To analyse patient data to elucidate the apparent association between an abnormal karyotype and tricuspid regurgitation found during fetal echocardiography at early gestations. SETTING: Tertiary referral centre for fetal medicine and cardiology. METHODS: Fetuses between 11 and 14 weeks' gestation were selected for detailed echocardiography. Referral reasons were increased nuchal translucency, a suspected cardiac or extracardiac malformation, and a family history of cardiac malformation. INTERVENTION: The fetus was imaged transabdominally. The four chamber view, outflow tracts, arterial duct, and aortic arch were assessed on cross sectional imaging and colour flow mapping. Pulsed Doppler of the atrioventricular valves was recorded if possible. Subsequently, the fetal karyotype was ascertained by chorionic villous sampling. RESULTS: Pulsed Doppler recording of the tricuspid valve was obtained for 262 fetuses. Tricuspid regurgitation was present in 70 (27%) of these, of whom 58 (83%) proved to have karyotype anomalies. In contrast, 68 (35%) of those without tricuspid regurgitation were found to have karyotype anomalies (95% confidence interval 36% to 59%, p < 0.001). Structural heart defects were detected in 34 of the 58 (59%) with tricuspid regurgitation and in 22 (32%) of those without. The chromosome defect most frequently found to be associated with tricuspid regurgitation was trisomy 21, but all types of karyotypic anomalies were seen in association. CONCLUSION: A careful search for tricuspid regurgitation is an important aspect of the evaluation of the early fetus, as this is frequently a marker for chromosomal defects even in the absence of structural heart disease.

Chorionic Villi Sampling↗

Fetal cardiac abnormalities identified prior to 14 weeks' gestation.

OBJECTIVE: An increasing number of patients are presenting at early gestational age as being at high risk for congenital heart disease, as a result of ultrasound screening by nuchal translucency. The feasibility and accuracy of fetal echocardiography was assessed in a series of pregnancies studied before 14 weeks' gestation. METHODS: Echocardiography was attempted in 478 fetuses of crown-rump length 40.0-85.0 mm (median, 60.3 mm) with increased nuchal translucency, suspected abnormalities on routine scan or a family history of heart defect. The findings were related to results of autopsy, karyotyping, later scans and postnatal follow-up. RESULTS: Satisfactory images were obtained transabdominally in 402/478 (84.1%) and transvaginally in a further 13 patients. Cardiac defects were confidently identified in 60 fetuses and abnormalities of uncertain significance (isolated ventricular or great artery disproportion, or tricuspid regurgitation) were observed in a further 49. Defects were suspected in an additional 20 fetuses, and 286 were passed as normal. The karyotype was subsequently demonstrated to be abnormal in 70/286 (24.5%) fetuses with normal echocardiograms, and in 94/129 (72.9%) with abnormal or suspicious cardiac findings. Validation of the scan findings was possible in 241 fetuses. Normal heart structure was confirmed in 204 fetuses, and previously unsuspected cardiac abnormalities revealed in nine. Heart defects were verified in 28 fetuses, but five of these had important additional findings. There were false positive findings in three fetuses. CONCLUSIONS: Fetal echocardiography is feasible prior to 14 weeks' gestation. Cardiac defects, when present, may be identified or suspected in the majority of cases. In the risk group studied, heart defects were frequently a manifestation of chromosomal abnormality.

Chromosome Aberrations↗

Incidence of major structural cardiac defects associated with increased nuchal translucency but normal karyotype.

OBJECTIVE: To examine the association between increased nuchal translucency thickness and major cardiac defects in chromosomally normal fetuses. SETTING: Tertiary referral unit for fetal medicine and fetal cardiology. METHODS: During a 4-year period (January 1997 to January 2001), detailed echocardiography was performed in 1319 chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks of gestation. The incidence of major cardiac defects was examined in relation to the fetal NT at the 10-14-week scan. RESULTS: Major cardiac defects were diagnosed in 60 (4.5%) of the 1319 fetuses. In fetuses with a nuchal translucency thickness in the range of 2.5-3.4 mm, the incidence of major cardiac defects was 2.5% (18/722; 95% confidence interval, 1.5-3.9) and in those with a nuchal translucency thickness > or =3.5 mm, it was 7% (42/597; 95% confidence interval, 5.1-9.4). CONCLUSION: Specialist echocardiography is indicated in all fetuses with increased nuchal translucency thickness because, in such fetuses, the incidence of major cardiac defects is substantially higher than in pregnancies with maternal diabetes, family history and exposure to drugs, where fetal echocardiography is widely considered to be necessary.

Echocardiography↗

Isolated echogenic foci in the fetal heart as marker of chromosomal abnormality.

OBJECTIVE: To assess the effect of echogenic foci in the fetal heart on the risk for Down's syndrome. DESIGN: Prospective evaluation of fetal echocardiograms at a fetal cardiology referral center and systematic postnatal follow-up. A relative risk was calculated from the prevalence of echogenic foci in fetuses subsequently demonstrated to have trisomy 21 divided by that in normal fetuses. For a subgroup of 548 fetuses with echogenic foci but otherwise normal detailed anomaly scans, the expected number of trisomy 21 fetuses calculated from maternal age risks was compared with the observed number to derive a relative risk for isolated echogenic foci. RESULTS: Echogenic foci occurred in 905 of 6904 fetuses scanned, but after excluding those referred specifically because of an echogenic focus and those with heart defects, the incidence was 9.5%. Overall, echogenic foci were more frequent in fetuses with trisomy 21 than those without by a factor of 2.93. For the 548 fetuses with echogenic foci but otherwise normal detailed anomaly scans, the actual number of trisomy 21 fetuses exceeded that expected on the basis of maternal age risks by a factor of 5.54. Combination with data from several previous studies suggests a consensus relative risk of about 3.0. CONCLUSIONS: Echogenic foci are associated with increased risk of trisomy 21 even when present as an isolated finding. Their significance in an individual should be interpreted in the light of prior risk assessment based on maternal age and results of any first-trimester screening tests. We suggest that the prior risk is increased by a factor of 3.0.

Adult↗

Transcatheter coil occlusion of the arterial duct; results of the European Registry.

AIMS: To report on the data, collected by the Association for European Paediatric Cardiology (AEPC) Registry, on transcatheter coil occlusion of the arterial duct. METHODS AND RESULTS: A retrospective study was conducted of intention-to-treat data from 30 European and Middle Eastern tertiary referral centres which included an analysis of causes of suboptimal outcome. Since 1994, reports have been made on 1291 attempted coil occlusions of the arterial duct in 1258 patients. Median age at procedure was 4 years (range 0.1-52) and median weight was 29 kg (range 1.8-100). Following coil implantation, the immediate occlusion rate was 59%, which rose to 95% at 1 year. A suboptimal outcome occurred on 129 occasions (10% of procedures) and was defined as coil embolization, an abandoned procedure, persistent haemolysis, residual leak requiring a further procedure, flow impairment in adjacent structures and duct re-canalization. A number of clinical factors were chosen but only increasing duct size [odds ratio of 2.6:1 (CI 2-3.2)] and the presence of a tubular shaped duct [odds ratio 2.4:1 (CI 1.4-4)] were positively associated with an unfavourable outcome. CONCLUSION: The results of the European Registry support the view that transcatheter coil occlusion of the persistent arterial duct is a safe and effective procedure. Unfavourable outcomes are more likely when closing larger and/or tubular shaped ducts.

Adolescent↗

Atrioventricular septal defects diagnosed in fetal life: associated cardiac and extra-cardiac abnormalities and outcome.

OBJECTIVES: We sought to establish the outlook for fetuses diagnosed with atrioventricular septal defect (AVSD) prenatally and its relation to additional cardiac, extracardiac and chromosomal abnormalities. BACKGROUND: Prediction of likely outcome of AVSD presenting prenatally is complicated by the wide variation in associated features. METHODS: Computerized records from 14,726 pregnancies referred to a fetal cardiology center were reviewed retrospectively. Pathological reports, postnatal records, follow-up inquiries and review of echocardiographic video recordings supplemented analysis of the records for all those with AVSD. RESULTS: Atrioventricular septal defect was confirmed in 301 fetuses. Eighty-six (39%) of the 218 with known karyotype had trisomy 21, and 21/218 (10%) had other chromosome abnormalities. Right isomerism occurred in 37/301 (12%) fetuses, left isomerism in 62 (20%), mirror image atrial arrangement in 2 (1%), and 200 (67%) had usual arrangement. Atrioventricular septal defect occurred without any other intracardiac abnormality in 155 fetuses (51%). Extracardiac abnormalities and nonkaryotypic syndromes were evident in 40 fetuses (13%, confidence interval [CI] 9.5-17.1%). Uncomplicated cardiac anatomy was significantly associated with the presence of karyotype abnormality (p < 0.0001). Parents opted for termination of pregnancy in 175/298 (58.5%). For the continuing pregnancies, Kaplan-Meier estimates for live birth, survival past the neonatal period and survival to three years were 82% (CI 75.3-88.9%), 55% (CI 46.0%-0/64.3%) and 38% (CI 27.1-48.6%), respectively. Fetal hydrops and earlier year of diagnosis were independent variables with adverse influence on survival. CONCLUSIONS: Despite some improvements in the outlook for AVSD diagnosed prenatally, the overall prognosis remains considerably poorer than that implied from surgical series. The detection of associated cardiac and extracardiac abnormalities is important in order to give the best indication of the likely outcome when counseling parents.

Abnormalities, Multiple↗

Early diagnosis of major cardiac defects in chromosomally normal fetuses with increased nuchal translucency.

OBJECTIVE: To determine the value of early ultrasound examination for prenatal diagnosis of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks of gestation. DESIGN: Prospective audit. SETTING: Fetal Medicine Centre. METHODS: Specialist fetal echocardiography was carried out in 398 chromosomally normal fetuses with a nuchal translucency measurement above the 99th centile (> or = 3.5 mm). In the first 75 pregnancies the cardiac scan was carried out at 17-22 weeks and the next 323 cases had one scan at 13-17 weeks and another at 20-22 weeks. Pregnancy outcome was obtained in all of the cases. RESULTS: Major cardiac defects were present in 29 (7.3% of 398) cases and in 28 of these the diagnosis was made by antenatal echocardiography. In 27 of the 29 fetuses with major cardiac defects echocardiography was carried out at 13-17 weeks and an abnormality was suspected in 24 of the cases (88%). CONCLUSIONS: Increased nuchal translucency in chromosomally normal fetuses is associated with an increased prevalence of major cardiac defects and, as such, is an indication for specialist fetal echocardiography. Most of the cardiac abnormalities are detectable on antenatal fetal echocardiography and many can be excluded by early scanning.

Echocardiography↗

Molecular cloning of human GATA-6 DNA binding protein: high levels of expression in heart and gut.

Human GATA-6 has been cloned from foetal heart by a combination of PCR-based methods and cDNA library screening. The 3.8 kbp cDNA has a coding sequence of 1347 bp the 449 aa protein is virtually identical in the two zinc-finger binding domains to other human GATA sequences, but varies considerably in the amino and carboxy terminal regions. The sequence shows greatest similarity to GATA-6-like sequences from rat, mouse, chicken and Xenopus. Northern analysis and in situ hybridisation show that GATA-6 is expressed at high levels in human adult and foetal heart as well as in gut derivatives. It is postulated that GATA-6, in concert with GATA-4, plays a crucial role in the regulation of cardiac differentiation.

Amino Acid Sequence↗

Effect of introducing balloon dilation of native aortic coarctation on overall outcome in infants and children.

The outcome of 40 consecutive newborns and children with normal cardiac connections presenting with unoperated (i.e., no previous surgical or balloon dilation treatment) aortic coarctation since the introduction of balloon dilation as a treatment option (group A) was compared retrospectively with that of a similar cohort of 38 patients (group B) presenting in the period immediately before the introduction of balloon dilation. Group A consisted of 18 newborns (< 30 days) and 22 children and Group B consisted of 20 newborns and 18 children. In group A, 30 patients had balloon dilation but 10 underwent surgery because of parental preference, unfavorable anatomy or for logistic reasons. Group B had conventional surgical repair by various methods. All patients were followed up clinically by Doppler echocardiography and, when possible, by magnetic resonance imaging. Repeat cardiac catheterization was only performed in those with suspected recoarctation. Survival and freedom from reintervention were investigated using Kaplan-Meier analysis. Patients of all ages in group A and those who had balloon dilation were at higher risk for reintervention (25 and 30%, respectively, at 1 year) than those in group B or those who had surgery (20 and 18%, respectively, at 1 year). Mortality was not significantly different between groups A and B, but there were 2 neonatal deaths directly attributable to the dilation procedure. Two patients developed aneurysms after dilation. Balloon dilation is an effective treatment for unoperated coarctation, but the recoarctation rate appears to be higher than for surgery.

Adolescent↗

Accuracy of central venous pressure measurements in the inferior vena cava in the ventilated child.

We compared central venous pressure measurements from three sites, superior vena cava, inferior vena cava and right atrium, in 12 children undergoing cardiac catheterization whilst on assisted ventilation. There was no significant difference between the mean pressures in the superior vena cava and the inferior vena cava. Furthermore, there was also no difference between the mean pressures in the inferior vena cava and the right atrium. Because of the greater safety of the placement of pressure monitoring lines in the inferior vena cava via the femoral vein, this approach should be the preferred route for central venous pressure monitoring in children.

Blood Pressure Determination↗

Perioperative haemodynamic effects of an intravenous infusion of calcium chloride in children following cardiac surgery.

Twelve children received an infusion of 10% calcium chloride 0.1 ml/kg to a maximum dose of 5 ml, infused over 5 min, following open heart surgery. Blood ionized calcium, systemic arterial pH, cardiac index, mean systemic arterial blood pressure and systemic vascular resistance index were measured at baseline and repeated 20 and 40 min following completion of the infusion. There was considerable overlap, with no significant differences in the response to the calcium chloride infusion between children with ionized hypocalcaemia (< 1.1 mmol/l) and those with ionized normocalcaemia when its effect on percentage change in either the haemodynamic or biochemical measurements was assessed (p > 0.2 for all measurements; Mann-Whitney). For this reason they were treated as a single group. Significant changes from baseline were noted in mean systemic arterial pressure (p < 0.02), cardiac index (p < 0.01) and systemic vascular resistance index (p < 0.01) after completion of the calcium chloride infusion when analysed using Friedman's two-way analysis of variance. A significant increase in mean systemic arterial blood pressure occurs after an infusion of 10% calcium chloride as a direct result of an increase in the systemic vascular resistance index with a concomitant decrease in cardiac index.

Blood Pressure↗

Percutaneous transcatheter retrieval of misplaced therapeutic embolisation devices.

OBJECTIVE: To assess the incidence and subsequent management of misplaced devices as a complication of therapeutic embolisation procedures. DESIGN: Retrospective review of case notes, cardiac catheterisation reports, and angiograms. SETTING: Tertiary referral centre for congenital heart disease. PATIENTS: 205 consecutive children and adults undergoing therapeutic embolisation for congenital heart disease in the 10 years up to 1 April 1993. This group had 231 therapeutic embolisation procedures at 241 sites using coils, umbrella devices, or detachable balloons. MAIN OUTCOME MEASURES: Incidences of misplacement and retrieval of the device; morbidity and mortality. RESULTS: The incidence of misplacement was 3% (10/332) of devices deployed and 4.3% (10/231) of procedures performed. Retrieval from distal pulmonary arteries was not attempted in two patients, but transcatheter retrieval of coils and umbrellas from systemic and pulmonary vessels, using snares or retrieval baskets, was successful in the remaining eight. There were no deaths or serious sequelae related to the procedure, but one patient required femoral arteriotomy for removal of an umbrella device retrieved only as far as the groin. In four of the five most recent cases, the misplaced device was retrieved and the therapeutic embolisation was completed at the same procedure. CONCLUSIONS: Misplacement of a device during therapeutic embolisation is a recognised complication that can be satisfactorily dealt with by transcatheter retrieval without recourse to surgery. For retrieval to be successful it is important to have a wide selection of retrieval equipment available and to be conversant with its use.

Adolescent↗

Rapid diagnosis of the cause of pneumoperitoneum in ventilated asthmatic children.

Two asthmatic children developed a pneumoperitoneum whilst being mechanically ventilated. A quick and accurate diagnosis as to the cause of the pneumoperitoneum was made by analysing the partial pressure of oxygen in the intraperitoneal free gas. This analysis helped to diagnose an intestinal perforation in one child and an air leak from lung barotrauma in the other. There was minimal delay in the surgical treatment of the child with intestinal perforation and in the other, an unnecessary laparotomy was avoided.

Asthma↗

Core-peripheral temperature gradient in children: does it reflect clinically important changes in circulatory haemodynamics?

Following open heart surgery, changes in core and peripheral skin temperature and changes in the core-peripheral temperature gradient were measured in 10 children. These were correlated with changes in cardiac index, systemic vascular resistance index, mean arterial pressure and urinary output. During the study intervals, which lasted 1 h each, no changes in medical management were made. Using Spearman's rank correlation, only a change in central venous pressure was found to correlate with a change in the core-peripheral temperature gradient. We conclude that a change in the core-peripheral temperature will give valuable information about the patient's intravascular volume.

Blood Pressure↗