Search

Background: Bipolar radiofrequency (RF) ablation strategies are increasingly used, mainly to target deep myocardial reentrant circuits responsible for ventricular tachycardia that cannot be extinguished with traditional unipolar RF ablation. Because this strategy is novel, factors that affect lesion geometry and steam pop formation require further investigation. Objective: To assess the effect of contact force, power, and time on the resulting lesion geometry and the risk of steam pop formation during bipolar RF ablation of thick myocardial tissue. Methods: A custom ex vivo bipolar ablation model was used to assess lesion formation. A combination of parallel and perpendicular configurations of ablation catheters was used to create lesions by varying force (20g, 30g, or 40g), power (30 or 40 W), and time (20, 30, 45, or 60 seconds). Lesion dimensions and the incidence of steam pops were recorded and then analyzed with binary logistic regression and multiple linear regression. Results: In bipolar ablation, lesion transmurality was most affected by the amount of time RF energy was applied. Durations longer than 20 seconds resulted in lesions deeper than half the tissue thickness. Steam pop formation was more frequent in thinner tissue, at longer ablation times, and at higher powers. Conclusion: The parameters assessed in this ex vivo model could be used as guidelines for future in vivo work and clinical evaluation of interventricular septal bipolar ablation.

Objective: Guidelines for pharmacologic obstetric venous thromboembolism (VTE) prophylaxis from the American Congress of Obstetricians (ACOG), the Royal College of Obstetricians and Gynaecologists (RCOG), and the American College of Chest Physicians (Chest) vary significantly. The objective of this study was to determine the practical implications of these recommendations in terms of prophylaxis rates for a tertiary obstetric population.Study Design: Cross-sectional.Setting: Tertiary referral hospital.Population: Patients post-operative day 1 after caesarean delivery.Methods: This cross-sectional study evaluated rates of pharmacologic prophylaxis for women based on RCOG, ACOG, and Chest recommendations. Medical, obstetric, and demographic risk factors for thromboembolism were reviewed for individual patients. Rates of prophylaxis based on each of the guidelines with 95% confidence intervals were calculated.Outcome Measure: Recommended pharmacologic prophylaxis.Results: About 293 patients were included in the analysis. Under RCOG guidelines, 85.0% of patients would receive post-caesarean pharmacologic prophylaxis [95% confidence interval (CI) 80.5-88.6%] compared with 1.0% of patients under ACOG guidelines (95% CI 0.3-3.0%) and 34.8% of patients under Chest guidelines (95% CI 29.6-40.4%). Caesarean during labour, obesity, advanced maternal age, pre-eclampsia, and multiple gestation were among the most commonrisk factors.Conclusion: Recommended prophylaxis differed significantly. Under ACOG recommendations a small minority of patients would receive prophylaxis, whereas under RCOG recommendations a large majority of patients would receive low-molecular-weight heparin. Given the large differences in prophylaxis rates for post-caesarean thromboprophylaxis based on different guidelines, further research is urgently needed to compare the risks and benefits of recommendations.Tweetable Abstract: Recommendations from major society guidelines for post-caesarean thromboprophylaxis differ greatly. [ABSTRACT FROM AUTHOR]

In contrast to the generally encouraging trend regarding global maternal mortality, there has been an apparent increase in the maternal mortality ratio in the United States. Although maternal death remains a relatively rare adverse event in this country, programs to reduce maternal mortality also will result in a reduction in maternal morbidity, which is a far more prevalent problem. Progress in the field of maternal-fetal medicine over the past several decades has been largely attributable to improvements in fetal and neonatal medicine. We need to develop an organized, national approach focused on reducing maternal mortality and morbidity. The goal will be to outline a specific plan for clinical, educational, and research initiatives to put the "M" back in maternal-fetal medicine. [ABSTRACT FROM AUTHOR]

Fetomaternal hemorrhage refers to the entry of fetal blood into the maternal circulation before or during delivery. Antenatal fetomaternal hemorrhage is a pathological condition with a wide spectrum of clinical variation. Secondary to the resultant anemia, fetomaternal hemorrhage may have devastating consequences for the fetus such as neurologic injury, stillbirth, or neonatal death. Presentation is frequently without an evident precipitating factor. Recognition may become apparent only after injury has occurred, if at all. The most common antenatal presentation is decreased fetal activity and a heightened index of suspicion is warranted in cases of persistent maternal perception of decreased fetal movements. The diagnostic standard, the Kleihauer-Betke screen, has several limitations. Management remains challenging. When detected antenatally, cordocentesis with intrauterine transfusion may be attempted to correct the anemia; however, repeat intrauterine transfusion or delivery may be necessitated to correct ongoing bleeding. Although the occurrence of large antenatal fetomaternal hemorrhage is fortunately rare, this entity likely remains underreported and underrecognized. A national registry should be created to advance our learning across institutions by reviewing the clinical presentations of fetomaternal hemorrhage, the variety of fetal heart rate tracings observed, the management strategies undertaken, and the outcomes achieved. [ABSTRACT FROM AUTHOR]

Objective: The FASTER trial compared first and second trimester screening methods for aneuploidy. We examined relationships between maternal serum markers and common congenital anomalies in the pediatric outcome data set of 36 837 subjects.Methods: We used nested case-control studies, with cases defined by the most common anomalies in our follow-up database, and up to four controls matched by enrollment site, maternal age and race, enrollment gestational age, and infant gender. Serum markers were dichotomized to > or = 2 or < 0.5 multiples of the median (MoM). Odds ratios (ORs) and 95% confidence intervals (CI) were estimated.Results: Statistically significant (p < 0.05) associations were found between inhibin A > or = 2 MoM with fetal multicystic dysplastic kidney (MCDK) (OR = 27.5, 95% CI: 2.8-267.7) and two-vessel cord (OR = 4.22, 95% CI:1.6-10.9); hCG of > or = 2 MoM with MCDK (OR = 19.56, 95% CI: 1.9-196.2) and hydrocele (OR = 2.48, 95% CI: 1.3-4.6); and PAPP-A > or = 2.0 MoM with hydrocele (OR = 1.88, 95% CI:1.1-3.3).Conclusion: In this large prospective study, significant associations were found between several maternal serum markers and congenital anomalies. This suggests potential additional benefits to screening programs that are primarily designed to detect aneuploidy. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Comparison of contingent, step-wise and integrated screening policies. METHODS: Mid-trimester Down syndrome risks were retrospectively calculated from FaSTER trial data. For contingent screening, initial risk was calculated from ultrasound measurement of nuchal translucency (NT), maternal serum pregnancy-associated plasma protein (PAPP)-A and free beta-human chorionic gonadotrophin (hCG) at 11-13 weeks, and classified positive (>1 in 30), borderline (1 in 30-1500) or negative. Borderline risks were recalculated using alpha-fetoprotein, hCG, unconjugated estriol (uE3) and inhibin at 15-18 weeks, and reclassified as positive (>1 in 270) or negative. For step-wise screening, initial negative risks were also recalculated. For integrated screening, a single risk was calculated from NT, PAPP-A and the second trimester markers. RESULTS: There were 86 Down syndrome and 32,269 unaffected pregancies. The detection rate for contingent screening was 91% and false-positive rate was 4.5%; initial detection rate was 60%, initial false-positive rate was 1.2% and borderline risk was 23%. Step-wise screening had 92% detection rate and 5.1% false-positive rate; integrated screening had 88% and 4.9% respectively. CONCLUSION: As predicted by modelling, the contingent screening detection rate for a fixed false-positive rate is comparable with step-wise and integrated screening, but substantially reduces the number needing to return for second trimester testing. [ABSTRACT FROM AUTHOR]

Increasingly, women are choosing first-trimester risk assessment for Down syndrome and other aneuploid conditions. Recent studies have suggested that adding ultrasound assessment of the nasal bone to nuchal translucency thickness and maternal serum analytes in the first trimester will improve performance. This report assesses the current literature and discusses practical issues that must be addressed before widespread implementation of nasal bone screening in the United States. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study was undertaken to determine whether obesity is associated with obstetric complications and cesarean delivery. METHODS: A large prospective multicenter database was studied. Subjects were divided into 3 groups: body mass index (BMI) less than 30 (control), 30 to 34.9 (obese), and 35 or greater (morbidly obese). Groups were compared by using univariate and multivariable logistic regression analyses. RESULTS: The study included 16,102 patients: 3,752 control, 1,473 obese, and 877 morbidly obese patients. Obesity and morbid obesity had a statistically significant association with gestational hypertension (odds ratios [ORs] 2.5 and 3.2), preeclampsia (ORs 1.6 and 3.3), gestational diabetes (ORs 2.6 and 4.0), and fetal birth weight greater than 4000 g (ORs 1.7 and 1.9) and greater than 4500 g (ORs 2.0 and 2.4). For nulliparous patients, the cesarean delivery rate was 20.7% for the control group, 33.8% for obese, and 47.4% for morbidly obese patients. CONCLUSION: Obesity is an independent risk factor for adverse obstetric outcome and is significantly associated with an increased cesarean delivery rate. [ABSTRACT FROM AUTHOR]

Screening for Down syndrome is an important part of routine antenatal care. The most common screening method in the United States involves the assessment of a combination of factors: maternal age, multiple second-trimester serum markers, and second-trimester ultrasonography (as a so-called "genetic sonogram"). More recently, however, there has been significant interest in first-trimester methods of screening, including screening for first-trimester serum markers and the sonographic measurement of fetal nuchal translucency. Multiple studies have demonstrated that fetal nuchal translucency has the potential of being a very powerful predictor of fetal aneuploidy. However, for clinicians a large void remains between this knowledge and the practical issues that must be addressed prior to endorsing this form of screening for widespread use. This article provides an objective assessment of the literature describing nuchal translucency, as well as some adjunct first-trimester sonographic techniques, such as ductus venosus flow and nasal bone studies. Additionally, a detailed description of practical problems that might limit the implementation of this form of screening is presented. [ABSTRACT FROM AUTHOR]

When the stomach, liver, or intestines herniate into the chest cavity of a fetus with this anomaly, they compress the fetal lung. Fewer than one third of all fetuses diagnosed prenatally with this often fatal defect will survive without significant morbidity. [ABSTRACT FROM AUTHOR]

In Part I of this symposium ('New developments in OB ultrasound,' in the May 2001 issue), we looked at advances in 3-D U/S, compound scanning, tissue harmonics, and telesonography. This final installment, like its predecessor, was taped in Reno, Nev., at this year's Annual Meeting of the Society for Maternal-Fetal Medicine (SMFM). In Part II we consider how those technological developments will affect our practices, specifically discussing the role of nuchal translucency (NT) measurements in screening for fetal Down syndrome, the benefits of late first-trimester anatomy scans, and middle cerebral artery Dopplers. The more specialized topics of fetal neural sonography and fetal echocardiography will appear exclusively on Contemporary OB/GYN's Web site: www.contemporaryobgyn.net . [ABSTRACT FROM AUTHOR]