Lewis Shenker

CARDIAC DOPPLER FLOW VELOCITIES IN HUMAN FETUSES

Cardiac Doppler flow velocity studies were performed in normal human fetuses between 18 and 40 weeks of gestation. Two-dimensional linear array and sector scanning techniques were used for the initial evaluation of the fetuses, which included a standard ultrasound examination to determine normal anatomy and estimated gestational age and weight. Fetal cardiac ultrasound examination was then performed, with four-chamber, short-axis/great vessel, long-axis/left ventricular outflow tract, and aortic arch views obtained. Pulsed echo Doppler instrumentation was used to obtain flow velocity measurements through the tricuspid, pulmonary outflow, mitral, and aortic outflow regions. Calculation of transvalve volume flow for mitral and tricuspid valves was performed by combining the valve anulus sizes and calculated mean temporal velocities for the valves. Maximal flow velocities were greater through the tricuspid (mean maximal velocity 51 +/- 1.2 [SE] cm/sec) than through the mitral (47 +/- 1.1 cm/sec; p less than .05) valve regions, with a wide range of scatter for results between fetuses but less than 6% average variation in the individual fetuses during gestation. For 18 fetuses, right heart dimensions and volume flows (mean 307 + 30 ml/kg/min) were greater than left heart dimensions and volume flows (232 +/- 25 ml/kg/min). Doppler echocardiography may prove to be useful as an adjunct to imaging echocardiography for evaluation of fetal cardiac anatomy and function.

Doppler echocardiographic studies of diastolic function in the human fetal heart: Changes during gestation

With the combined use of two-dimensional ultrasound and Doppler echocardiography, noninvasive examination of the human fetal heart and circulation has recently become possible. These techniques were employed to investigate diastolic atrioventricular valve flow in the fetal heart in 120 fetuses studied between 17 and 42 weeks of gestation. Two-dimensional ultrasound was used to examine fetal and intrauterine anatomy, and estimates of gestational age were made based on biparietal diameters and femur lengths. Doppler echocardiography was performed with a 3.5 or 5 MHz Doppler sector scanner. Flow velocity patterns were obtained through the tricuspid and mitral valves during diastole. Peak flow velocity during late diastole or atrial contraction (A) was compared with peak flow velocity during early diastole (E) in four groups of fetuses: Group 1, 17 to 24 weeks of gestation; Group 2, 25 to 30 weeks; Group 3, 31 to 36 weeks; and Group 4, 37 to 42 weeks. The ratio of A to E decreased significantly as gestational age advanced, from 1.56 +/- 0.06 (+/- SE) to 1.22 +/- 0.03 across the tricuspid valve (p less than 0.001) and from 1.55 +/- 0.04 to 1.22 +/- 0.06 across the mitral valve (p less than 0.001). In tricuspid valve measurements, peak flow velocity during early diastole increased from 26.3 +/- 2.0 cm/s in Group 1 to 36.5 +/- 1.7 cm/s in Group 4 (p less than 0.001), whereas peak flow velocity during atrial contraction did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in intracardiac Doppler blood flow velocities in fetuses with absent umbilical artery diastolic flow

Umbilical artery Doppler blood flow velocity studies were used to identify 14 fetuses with absent flow during diastole to determine the significance of absent umbilical artery diastolic flow. Outcomes of these fetuses were recorded, and the associated intracardiac Doppler changes were identified in 12 of them. Maximal and mean intracardiac flow velocities were measured, and volume flows through the right (tricuspid valve, pulmonary valve) and left (mitral valve, aortic valve) sides of the heart were compared. Ratios of intracardiac peak flow velocity in late diastole to peak flow velocity in early diastole were calculated. Eleven fetuses had intrauterine growth retardation, and four had multiple congenital anomalies. Fetuses with no diastolic flow in the umbilical artery had increased volume flow across the tricuspid and pulmonary valves compared with normal fetuses of similar weights. The ratio of right-sided to left-sided volume flow in the heart (2.15:1) was increased compared with values in normal fetuses (1.33:1, p less than 0.01). The ratio of late diastolic to early diastolic peak flow velocities across the mitral valve was decreased (p less than 0.01). Absent umbilical artery diastolic flow is associated with increased tricuspid and pulmonary valve volume flow and changes in mitral flow velocity patterns, which suggests that there are alterations in left ventricular function.

Prenatal ultrasound diagnosis of hypoplastic left heart syndrome in utero associated with hydrops fetalis

Abstract Ultrasound is widely used in obstetrics as a screening technique for fetal size and maturity, placental structure and function, and for detection of fetal congenital malformations in complicated pregnancies. 1–3 Our own work on qualitative and quantitative fetal echocardiography 4,5 and the work of others 6 has suggested that high resolution ultrasound can be used to assess fetal heart rhythm and function, and can detect congenital heart malformations before birth. In this report, we delineate prenatal diagnosis of hypoplastic left heart syndrome in a fetus with signs of hydrops fetalis, who was found after cesarean section to have associated trisomy 13. Additionally, we diagnosed the ususual occurrence of an intraventricular thrombus within the hypoplastic left ventricular cavity. The fetal ultrasound evaluation was of major importance in the perinatal management of both mother and unborn child.

Significance of oligohydramnios complicating pregnancy

Oligohydramnios is a serious complication of pregnancy that is associated with a poor perinatal outcome. Eighty pregnancies complicated by oligohydramnios constitute the basis for this retrospective study. Forty patients had premature rupture of the membranes; of these, outcomes were good in 25. Twelve of 14 fetuses with oligohydramnios and intrauterine growth retardation survived. None of the nine fetuses with severe renal anomalies lived. None of the twins with twin-twin transfusion and oligohydramnios survived. Six pregnancies with oligohydramnios and premature separation of the placenta were identified; all of these resulted in fetal or neonatal death during the second trimester.

Fetal pericardial effusion

Forty-four fetuses with pericardial effusions have been identified by ultrasonographic examinations. The clinical histories and courses of these patients were reviewed. At least eight different clinical features accompanied and were probably responsible for the pericardial effusions. The most common cause of a fetal pericardial effusion was heart failure (13 fetuses). Fetal renal cystic dysplasia with oligohydramnios and other anomalies was present in six fetuses. Four of this group had microscopic evidence of pericarditis on postmortem examination. Fetal pericardial effusions are always a manifestation of another disease process often presenting as fetal hydrops. Some pericardial effusions are transient. The etiologic origin of fetal pericardial effusions differs from that in the child or adult.

Fetal cardiac Doppler flow studies in prenatal diagnosis of heart disease

The prenatal diagnosis of fetal cardiac disease has become increasingly accurate as the technology of ultrasound has improved. Although two-dimensional real-time ultrasound remains the primary method of diagnosis, Doppler blood flow velocity estimates can provide valuable pathophysiologic information to support the anatomic diagnosis. We present six cases in which Doppler studies contributed to the accuracy of the diagnosis of fetal heart disease, including tetralogy of Fallot, right and left ventricular hypoplasia, atrioventricular canal defect, double-outlet right ventricle, and pulmonic stenosis. Velocities in these cases are compared with those in normal fetuses. If Doppler flow velocities are not consistent with the observed morphologic changes, further observations are indicated. Inasmuch as most anatomical heart lesions result in altered flow patterns, Doppler investigations of intracardiac and extracardiac flow should be a routine component of the fetal echocardiogram when structural abnormalities are found.

Balanced translocation karyotypes in patients with repetitive abortion: Case study and literature review

Cytogenetic studies were conducted upon 100 consecutive couples with abortions. Eight balanced carrier translocation karyotypes were discovered (8%): three cases of Robertsonian translocations and five reciprocal translocations. Two structural variant karyotypes and a poly-X mosaic were also found. A review of the literature on repetitive abortion revealed 82 balanced translocations in 1,331 couples, a rate of 6.2%. Cytogenetic studied should be routine for patients with repetitive abortion. In the pooled series, 3.7% of couples with translocation had wastage, including some with normal offspring; 9.2% had malformed offspring; 62% of the carrier couples lacked the malformation history. Seventy-four percent of the translocations were reciprocal; risk rates for imbalanced progeny were undefined for 90% of the carrier couples. Only 11 imbalanced conceptuses were demonstrated cytogenetically in 262 pregnancies of the carrier group.

Doppler flow velocities in single umbilical arteries

Fetal compromise has been associated with an umbilical artery waveform pattern of low or absent diastolic velocity relative to systolic velocity. Fetuses with single umbilical arteries have an increased risk of major malformations, mortality, retarded fetal growth, and prematurity. In this study Doppler flow velocities were obtained in 13 fetuses (four twin fetuses and nine singletons) with a single umbilical artery. Five (38%) fetuses, consisting of four singletons and one twin, had anomalies. Six (46%) fetuses were small for gestational age, including two twin fetuses and three singleton fetuses with anomalies. Three (23%) of the 13 systolic-to-diastolic velocity ratios were abnormally high. Whereas this is a higher rate of abnormal ratios than the reported 2% to 3% in control populations, it is interesting to note that 77% of fetuses with single umbilical arteries had normal systolic-to-diastolic ratios.

SEM-dissection of a human embryo derived from an ectopic pregnancy

A 6.5-week-old human embryo with an approximate crown-rump length of 13.2 mm was obtained from a tubal pregnancy. Two hours before surgical removal, the embryo was imaged with real time ultrasound and was noted to have rhythmic cardiac motion. Subsequent to surgical removal, the embryo was dissected free from the placenta and prepared for routine scanning electron microscopic (SEM) studies. Progressive stages of dissection with microsurgical instruments followed by SEM photography elucidated the three-dimensional aspects of embryonic development of many structures, including the lens placode, tongue bud, Rathkes pouch, atrial and ventricular foramina, primitive intestinal loop and undifferentiated external genitalia. Almost certainly, such clear views of dissected structures can contribute to our understanding of human embryonic development.