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Biomedical subjects

T Todros

Publications and source records attributed to T Todros.

At least 55 records · Page 3Linked to original sources
PubMed1995

Performance of Doppler ultrasonography as a screening test in low risk pregnancies: results of a multicentric study.

To assess the efficacy of the Doppler velocimetry of the uterine and umbilical arteries as a screening test for preeclampsia and fetal growth retardation, we studied 916 low risk pregnancies. The S/D ratios of the uterine and umbilical arteries were obtained at 19 to 24 weeks and at 26 to 31 weeks of gestational age. Mean values, receiver operator curves, and the diagnostic accuracy of the tests were calculated for the following end-points: (1) pregnancy-induced hypertension, (2) low birth weight for gestational age, (3) small for gestational age with abnormal outcome, (4) pregnancy-induced hypertension needing preterm delivery. The prevalences for these outcomes were 3.4%, 4.6%, 1%, and 0.7%, respectively. The study was blinded. The umbilical and uterine artery S/D ratios were significantly higher in the abnormal than in the normal outcome group. When uterine arteries were studied at 19 to 24 weeks, sensitivity was 59% in the detection of pregnancy-induced hypertension, 11% in the detection of small for gestational age fetuses, 33% in the detection of small for gestational age fetuses with abnormal outcome, and 83% in the detection of pregnancy induced hypertension needing preterm delivery; the corresponding values for specificity were 69%, 94%, 94%, and 68%. At 26 to 31 weeks the sensitivity values were respectively, 69%, 58%, 75%, and 100% and specificity values were 80%, 59%, 39%, and 79%. When umbilical arteries were studied at 19 to 24 weeks, sensitivity was 38% in the detection of pregnancy-induced hypertension, 46% in the detection of small for gestational age fetuses, 78% in the detection of small for gestational age fetuses with abnormal outcome, and 67% in the detection of pregnancy-induced hypertension needing preterm delivery. The corresponding values of specificity were 74% for all four groups. At 26 to 31 weeks the sensitivity values were 38%, 43%, 87%, and 67%, respectively, and specificity values were 80% for all four groups. We concluded that Doppler examinations of the uterine and umbilical arteries can detect, at midpregnancy, the severe forms of pregnancy-induced hypertension and small for gestational age fetuses but they cannot be used to screen a low risk population in which the prevalence of the disease is low, and hence the positive predictive value is low.

Adult↗
PubMed1995

[Prenatal diagnosis of thanatophoric dysplasia at the 20th week of pregnancy using ultrasonography].

We report on prenatal diagnosis of a fetus with thanatophoric dysplasia type 1 at 20 weeks gestation. The ultrasonographic examination showed shortened bowed limbs, narrow chest, relatively large head, protuberant abdomen, and hydramnios. Radiological and histological studies confirmed the aborted fetus had thanatophoric dysplasia. The differential prenatal diagnosis with other skeletal dysplasia is discussed.

Abortion, Therapeutic↗
PubMed1994

Clinical significance of absent or reversed end diastolic velocity waveforms in umbilical artery.

Doppler ultrasound provides a non invasive method to assess fetal haemodynamics. We looked at the outcome of doppler velocimetry of the umbilical artery in three groups of pregnancies: those with positive end diastolic velocities (PED; n = 214), absent end diastolic velocities (AED; n = 178) and reversed end diastolic velocities (RED; n = 67). We collected our data from 9 European centers. Logistic regression showed that compared with pregnancies with hypertension only, pregnancies complicated by intra uterine growth retardation (IUGR) had a higher risk of developing absent or reversed end diastolic velocity waveforms (ARED) flow. ARED flow in the umbilical artery (odds ratio: OR = 3.1). Pregnancies complicated by both IUGR and hypertension had an even higher risk (OR = 7.4). Maternal age and smoking habits did not influence the risk of developing ARED flow. The overall perinatal mortality rate was 28%. Significantly more neonates in the ARED flow group needed admittance to the neonatal intensive care unit (PED group 60%, AED group 96%, RED group 98%). The OR for perinatal mortality in pregnancies complicated by AED flow was 4.0 and in RED flow was 10.6, compared with PED flow, even after adjustment for menstrual age. ARED flow in the umbilical artery did not influence the risk of respiratory distress syndrome or necrotising enterocolitis of the neonate, but ARED flow significantly influenced the risk of cerebral haemorrhage, anaemia, or hypoglycaemia. We advise that pregnancies complicated by IUGR and/or hypertension should be followed up with doppler velocimetry to trace utero-placental problems as early as possible. A caesarean section is recommended in all pregnancies complicated by ARED flow if the gestational age and predicted neonatal weight can be handled by the local neonatal intensive care unit.

Adult↗
PubMed1994

Vitamin E supplementation in preeclampsia.

An oxidant/antioxidant imbalance has been suggested among the pathogenetic factors involved in preeclampsia. As vitamin E is one of the most important antioxidant body components, a nonrandomized controlled trial was undertaken in 36 preeclamptic patients in order to evaluate the effect of vitamin E supplementation (100-300 mg/day per os) on fetal and maternal outcome. Fetal mortality was similar in 14 patients treated with conventional therapy plus oral vitamin E supplementation (35%) and in 22 patients treated with conventional therapy only (36%). Furthermore, in both groups of patients proteinuria increased, and increased dosages of antihypertensive drugs were called for in order to control blood pressure. We conclude that, with these dosages and in case of an already established disease, vitamin E does not improve fetal outcome in severe preeclampsia. Furthermore, it does not show favorable effects on maternal hypertension and proteinuria.

Adult↗
PubMed1992

Modelling the feto-placental circulation: 1. A distributed network predicting umbilical haemodynamics throughout pregnancy.

The modifications of the Doppler flow velocity parameters occurring in the feto-placental circulation throughout pregnancy have been reproduced on the basis of a mathematical model. Some simple assumptions were made, such as the progressive development of a dichotomous villous vessel network and the increase of the perfusion pressure and of the umbilical arteries dimensions throughout pregnancy. Moreover, both the viscous and capacitive characteristics of the vascular bed were taken into consideration in order to predict the mean values of blood volume, flow and velocity and the pulsatility index. Their value is shown to depend on few parameters, and mainly on the cross-sectional area ratio between the vessels belonging to two succeeding generations.

Blood Flow Velocity↗
PubMed1992

Modelling the feto-placental circulation: 2. A continuous approach to explain normal and abnormal flow velocity waveforms in the umbilical arteries.

A mathematical model of the feto-placental circulation which describes the development of the placental vasculature throughout pregnancy on the basis of simple assumptions is used to simulate some abnormalities of the villous vascular tree which may affect the values of Doppler indices. In normal cases, the model shows a decreasing trend of the pulsatility index (PI) throughout pregnancy which is comparable to that observed in vivo. When a pathological interruption of the villous growth is simulated, the PI does not decrease any further, unless the input pressure keeps increasing. When various degrees of obliteration of the villous tree are simulated, either through an occlusive process or a reduction of the lumen of the vessels, the PI values increase and the volume flow decreases to a greater extent. The data predicted by the model are compared to those obtained in clinical studies and in experimental animal models.

Blood Flow Velocity↗
PubMed1992

[Risks of contraception and pregnancy in patients with congenital cardiopathies. Retrospective study on 108 patients].

108 women with congenital heart disease in child-bearing age (16-38 years, mean age 28) were followed up for a period of ten years. Possible complications of contraceptive methods, and incidence of full-term pregnancies, spontaneous abortions and cardiovascular complications during pregnancy and delivery, were considered. Half of these patients had a cyanotic congenital heart disease, 23 had left-to-right shunt mainly at atrial level, 18 had right and 14 left ventricular outflow tract obstruction. 60 women had previous surgical procedures for their congenital heart disease. 83% of the patients were in NYHA functional class I-II. No complications were found during oral contraceptive regimen during intrauterine device insertion with antibiotic prophylaxis, except for the development of pulmonary hypertension in one patient with an atrial septal defect. 146 pregnancies occurred, but only 89 were full-term. There was a high number of interrupted pregnancies, rarely for medical reasons. The incidence of spontaneous abortion was similar to that of normal population (18% versus 10-15%). Maternal cardiovascular complications were found in the 22% of the full-term pregnancies, but were well controlled by medical treatment. In conclusion, good family planning and pregnancies are possible in most young females with congenital heart disease. In the absence of cyanosis and pulmonary hypertension, oral contraception does not carry any particular risk. With appropriate medical care intrauterine devices may be an alternative in high risk patients. In the presence of a good cardiac function, a normal full-term pregnancy with an healty baby is the rule. A cesarean section is seldom needed.

Abortion, Spontaneous↗
PubMed1991

The length of pregnancy: an echographic reappraisal.

A study of 998 pregnant women was conducted to estimate the random errors in dating pregnancy by menstrual history and by ultrasound measurements of the fetus (crown-rump length or biparietal diameter before 20 weeks, menstrual age) as well as the biological variability of pregnancy length. The latter was found to be 7.74 days. The random errors made when dating pregnancy by menstrual history and by ultrasound measurements were 7.16 days and 4.26 days, respectively. (All variabilities are expressed as standard deviations). The differences between the two methods were mainly attributable to some large errors occurring when dating pregnancy on the basis of menstrual history. Differences between methods of more than 10 days were observed in about 10% of our population. When the two methods were used on the same patients to define a pregnancy as preterm, at term, or postterm, discrepancies were found in about 7% of cases.

Female↗
PubMed1991

Repeated albumin infusions do not lower blood pressure in preeclampsia.

Since intravascular volume contraction is regarded as an important pathological feature in preeclampsia, it has been proposed that plasma volume expansion could be a therapeutic manoeuver that interrupts the pathogenetic chain of hypovolemia inducing increased vascular resistance. Furthermore, tissue perfusion should be improved and, if albumin is used as plasma expander agent, interstitial edema should also be reduced. We report the results observed in an open pilot study in ten preeclamptic patients treated with daily albumin infusions (0.4 to 1 g/kg) from 7 to 36 days. No acute effects were shown on blood pressure, and the need for antihypertensive therapies did not decrease in the following days. Serial evaluation after at least five or ten days of repeated albumin infusions did not show stable changes in electrolytes excretion, renal clearances, serum protein concentration and hematocrit value, nor in aldosterone, renin and atrial natriuretic peptide basal levels, while proteinuria tended to increase. Uteroplacental and fetoplacental blood flow acutely ameliorated in 3 cases only after albumin 1 g/Kg, but reached basal values again on the next day. The clinical implications are that daily albumin infusions with this schedule dosage do not lower blood pressure and that they are unable to induce stable changes in renal function, uteroplacental and fetoplacental resistance. No maternal complications were observed during the conservative management, but fetal mortality was high (6/10). Given the uncontrolled study, we cannot know whether similar results had been achieved by conventional therapy only.

Adult↗
PubMed1990

Conservative management of fetal bigeminy arrhythmia leading to persistent bradycardia.

A case of persistent fetal bradycardia first detected at 32 weeks of gestational age is described. The diagnosis of atrial ectopic beats was made by means of M-mode echocardiography. Since the fetus was normally grown and showed no signs of distress, the vaginal route of delivery was allowed, also because continuous M-mode echocardiographic monitoring was possible during labour.

Adult↗
PubMed1989

Growth of fetuses of diabetic mothers.

Longitudinal ultrasonographic examinations, with measurements of fetal biparietal diameter and abdominal circumference, were performed in 85 diabetic pregnant women submitted to different treatment protocols. Curves of fetal growth parameters were obtained for each group of patients and for a control group of normal fetuses, applying the function y = k(MA)2.e-a(MA) to the ultrasonographic data. With the use of this function it was possible to demonstrate that there are no significant differences in the pattern of fetal growth when a strict metabolic control is obtained in diabetic pregnant women.

Adult↗
PubMed1989

Ratio between aldosterone and atrial natriuretic peptide in pregnancy.

The possibility of evaluating the ratio between aldosterone and atrial natriuretic peptide (ANP) instead of the two hormones by themselves in studying sodium handling in normal pregnancy and in preeclampsia in the steady state and following albumin infusion was examined in this study. In 32 normal pregnancies monitored monthly, the highest aldosterone/ANP ratio was observed in the last weeks (28.7 +/- 12), and dropped in the first postpartum week (3.6 +/- 2.8), without changes in fractional excretion of sodium. In 18 preeclamptic patients, the ratio was significantly lower than in normal pregnancy at the same gestational ages, and it was coupled with absolute reduction in the sodium excretion. Among preeclamptic patients, a significant inverse correlation (P less than 0.025) was revealed between the ratio and sodium excretion. Natriuresis in response to acute volume expansion with albumin infusion occurred only in 50% of preeclamptic patients, and was associated with an ANP increase, an aldosterone decrease, and a further decrease in the ratio. A blunted natriuresis was observed in cases with a particularly low prealbumin value of this ratio. Furthermore, in preeclampsia, a particularly low ratio seemed to be typical of the patients who showed poorer placental flows and fetal outcomes. These results suggest that the balance between aldosterone and ANP may be a useful index in understanding sodium homeostasis in these settings.

Adult↗
PubMed1989

Pregnancy-related acute renal failure.

From 1958 to 1987, 81 cases of pregnancy-related acute renal failure (PR-ARF) were observed (9% of the total number of acute renal failure [ARF] needing dialysis). In the three successive ten-year periods (1958-67, 1968-77, 1978-87) the incidence of PR-ARF fell from 43% to 2.8% with respect to the total number of ARF, and from 1/3,000 to 1/15,000 with respect to the total number of pregnancies. Maternal mortality was high (32%), with 5 cases of death in the last ten years. Irreversible renal damage was recorded in 11.6% of PR-ARF, and, in particular, in 26.3% of cases in preeclampsia-eclampsia (PE-E). Worse maternal and renal prognosis occurred in PE-E complicated by abruptio placentae. Neither disseminated intravascular coagulation (DIC), microangiopathic hemolytic anemia nor prostacyclin imbalance were significantly related to the severity of renal damage. Heparin therapy did not modify DIC evolution and renal outcome and was aggravated by severe hemorrhagic complications. In conclusion, PR-ARF has become a rare, but still critical occurrence, and the most effective measures would be a program of careful prevention.

Acute Kidney Injury↗
PubMed1988

The role of intravascular coagulation in pregnancy related acute renal failure.

Pregnancy-related acute renal failure (ARF) can include reversible tubular necrosis as well as irreversible cortical necrosis. Though pathogenetic mechanism are not fully understood, disseminated intravascular coagulation (DIC) probably plays a primary role. We report 25 cases of pregnancy-related ARF: 13 were associated with preeclampsia or eclampsia and 12 with obstetric complications. The following parameters were studied: partial thromboplastin, prothrombin and thrombin time, fibrinogen, anti-thrombin III and FDP levels, platelet count, whole blood clot lysis time and area, fragmented red cells (schistocytes) in the blood smear, hemoglobin, aptoglobin and LDH concentrations. DIC was scored in arbitrary units ranging from 12 to 36 and related to the clinical picture, renal outcome and the treatment employed. Five patients had irreversible renal damage, while 19 recovered fully; one patient died and no renal histology was available. The DIC score did not seem to have a significant relation to the severity of renal damage.

Acute Kidney Injury↗
PubMed1988

Pulmonary stenosis with intact ventricular septum: documentation of development of the lesion echocardiographically during fetal life.

We describe a case of severe pulmonary stenosis with intact interventricular septum diagnosed during fetal life at 34 weeks gestational age. An echocardiographic examination had been performed on the same fetus at 20 weeks, when no cardiac anomalies were observed. It is concluded that this form of pulmonary stenosis might be a lesion either acquired during fetal life or becoming progressively more severe in the prenatal period.

Diagnostic Errors↗
PubMed1987

Fitting growth curves to head and abdomen measurements of the fetus: a multicentric study.

Three different mathematical models were fitted to ultrasonic measurements of the biparietal diameter, head circumference, and abdomen circumference obtained from 1,426 healthy fetuses. The linear cubic function gives coefficients comparable with most previous studies, but it does not thoroughly explain fetal growth throughout pregnancy. Both the exponential-power function and the logistic-logarithmic function fit the raw data well and theoretically reflect the biological phenomena of human fetal growth. The characteristics of each model are discussed.

Abdomen↗