Effect of Angiotensin II on the Left Ventricular Function in a Near-Term Fetal Sheep with Metabolic Acidemia

We tested the hypothesis that, in acute metabolic acidemia, the fetal left ventricle (LV) has the capacity to increase its contractility in response to angiotensin II infusion. Eleven ewes and their fetuses were instrumented at 127–138/145 days of gestation. The effect of angiotensin II on fetal LV function was assessed using intraventricular pressure catheter and tissue Doppler imaging (TDI). Angiotensin II increased fetal arterial blood pressure, whereas pH and pO2 decreased. The heart rate and systemic venous pressure were not affected significantly. The LV end-diastolic and end-systolic pressures, as well as dP/dtmax, increased. The TDI-derived LV longitudinal myocardial isovolumic contraction velocity and its acceleration and velocity during early filling were higher than those at baseline. The incidence of absent isovolumic relaxation velocity was greater during angiotensin II infusion. In summary, during acute metabolic acidemia, the fetal left ventricle could increase its contractility in response to inotropic stimulus even in the presence of increased afterload. The diastolic LV function parameters were altered by angiotensin II

Effect of hypoxemia on fetal ventricular deformation in a chronically instrumented sheep model

We hypothesized that in near-term sheep fetuses, hypoxemia changes myocardial function as reflected in altered ventricular deformation on speckle-tracking echocardiography. Fetuses in 21 pregnant sheep were instrumented. After 4 d of recovery, fetal cardiac function was assessed by echocardiography at baseline, after 30 and 120 min of induced fetal hypoxemia and after its reversal. Left (LV) and right (RV) ventricular cardiac output and myocardial strain were measured. Baseline mean (standard deviation [ SD]) LV and RV global longitudinal strains were -18.7% (3.8) and -14.3% (5.3). Baseline RV global longitudinal and circumferential deformations were less compared with those of the left ventricle (p = 0.016 and p <0.005). LV, but not RV, global longitudinal strain was decreased (p = 0.003) compared with baseline with hypoxemia. Circumferential and radial strains did not exhibit significant changes. In the near-term sheep fetus, LV global longitudinal and circumferential strains are more negative than RV strains. Acute hypoxemia leads to LV rather than RV dysfunction as reflected by decreased deformation. (C) 2017 World Federation for Ultrasound in Medicine & Biology.Peer reviewe

Fetal cardiovascular hemodynamics in type 1 diabetic pregnancies at near-term gestation

Introduction Poor glycemic control in maternal type 1 diabetes mellitus during pregnancy can affect fetal cardiac and placental function. However, studies concerning fetal central hemodynamics have revealed conflicting results. We hypothesized that in pregnancies complicated by maternal type 1 diabetes, fetal cardiovascular and placental hemodynamics are comparable to the control fetuses at near-term gestation. In addition, we investigated the relationship between newborn serum biomarkers of cardiac function and fetal cardiovascular and placental hemodynamics. Furthermore, we studied whether maternal diabetes is associated with placental inflammation. Material and methods In this prospective case-control study, fetal central and peripheral hemodynamics were assessed by ultrasonography in 33 women with type 1 diabetes and in 67 controls with singleton pregnancies between 34(+2)and 40(+2)gestational weeks. Newborn umbilical cord serum was collected to analyze cardiac natriuretic peptides (atrial and B-type natriuretic peptides) and troponin T concentrations. Placental tissue samples were obtained for cytokine analyses. Results Fetal ventricular wall thicknesses were greater and weight-adjusted stroke volumes and cardiac outputs were lower in the type 1 diabetes group than in the control group. Pulsatility in the aortic isthmus and inferior vena cava blood flow velocity waveforms was greater in the type 1 diabetes group fetuses than in the controls. A positive correlation was found between branch pulmonary artery and aortic isthmus pulsatility index values. Umbilical artery pulsatility indices were comparable between the groups. Umbilical cord serum natriuretic peptide and troponin T concentrations were elevated in the type 1 diabetes fetuses. These cardiac biomarkers correlated significantly with cardiovascular hemodynamics. Placental cytokine levels were not different between the groups. Conclusions In maternal type 1 diabetes pregnancies, fetal cardiovascular hemodynamics is impaired. Maternal type 1 diabetes does not seem to alter placental vascular impedance or induce placental inflammation.</p

Nifedipine disturbs fetal cardiac function during hypoxemia in a chronic sheep model at near term gestation

BACKGROUND: Nifedipine is a widely used drug in pregnancies complicated by maternal hypertensive disorders that can be associated with placental insufficiency and fetal hypoxemia. The evidence regarding fetal myocardial responses to nifedipine in hypoxemia is limited. OBJECTIVE: We hypothesized that nifedipine would not impair fetal sheep cardiac function under hypoxemic environment. In particular, we investigated the effects of nifedipine on fetal ventricular functional parameters and cardiac output. STUDY DESIGN: A total of 21 chronically instrumented fetal sheep at 122 to 134 gestational days (term, 145 days) were included in this study. Fetal cardiac function was evaluated by measuring global longitudinal strain, indices describing ventricular systolic and diastolic function, and cardiac outputs using two-dimensional speckle tracking and tissue and spectral pulsed-wave Doppler echocardiography. Fetal carotid artery blood pressure and blood gas values were invasively monitored. After baseline data collection, fetal hypoxemia was induced by maternal hyperoxygenation. After hypoxemia phase data collection, 9 fetuses received nifedipine infusion, and 12 fetuses received saline infusion. Data were collected 30 and 120 minutes after the infusion was started. After 120 minutes of data collection, maternal and fetal oxygenation were normalized, and normoxemia phase data were collected, while infusion was continued. RESULTS: Hypoxemia decreased fetal carotid artery mean arterial pressure from 40 (8) mm Hg to 35 (8) mm Hg (P CONCLUSION: In hypoxemic fetus, nifedipine impaired right ventricular function and reduced its cardiac output. The detrimental effects of nifedipine on fetal right ventricular function were abolished, when normoxemia was restored. Our findings suggest that in a hypoxemic environment nifedipine triggers detrimental effects on fetal right ventricular function.Peer reviewe

Effects of nifedipine and sildenafil on placental hemodynamics and gas exchange during fetal hypoxemia in a chronic sheep model

Introduction We hypothesized that nifedipine and sildenafil would have no detrimental effects on placental hemodynamics and gas exchange under fetal hypoxemia. Methods In 33 chronically instrumented fetal sheep, placental volume blood flow (QPlac) and umbilical artery (UA) vascular impedance were measured by Doppler ultrasonography. Fetal carotid artery blood pressure and blood gas values were monitored. After baseline data collection, maternal and fetal hypoxemia were induced. Following hypoxemia phase data collection, 12 fetuses received sildenafil and 9 fetuses nifedipine infusion, and 12 fetuses served as controls receiving saline infusion. Data were collected 30 and 120 min after infusion was started. Then maternal oxygenation was normalized and normoxemia phase data were collected, while infusion was continued. Results Hypoxemia significantly decreased fetal pO2 and blood pressure. In the sildenafil group at 30- and 120-min hypoxemia + infusion phases, fetal blood pressure and QPlac were significantly lower and pCO2 higher than at baseline without returning to baseline level at normoxemia + infusion phase. In hypoxemia, nifedipine did not affect fetal blood pressure or placental hemodynamics. Both in the sildenafil and nifedipine groups, fetal pO2 remained significantly lower at normoxemia + infusion phase than in the control group. Umbilical artery vascular impedance did not change during the experiment. Discussion In fetal hypoxemia, sildenafil had detrimental effects on placental hemodynamics that disturbed placental gas exchange. Nifedipine did not alter placental hemodynamics in hypoxemia but disturbed placental gas exchange upon returning to normoxemia. Umbilical artery vascular impedance did not reflect alterations in placental hemodynamics.Peer reviewe

Effect of Sildenafil on Pulmonary Circulation and Cardiovascular Function in Near-Term Fetal Sheep During Hypoxemia

Sildenafil is a potential new treatment for placental insufficiency in human pregnancies as it reduces the breakdown of vasodilator nitric oxide. Pulmonary vasodilatation is observed in normoxemic fetuses following sildenafil administration. Placental insufficiency often leads to fetal hypoxemia that can cause pulmonary vasoconstriction and fetal cardiac dysfunction as evidenced by reduced isovolumic myocardial velocities. We tested the hypotheses that sildenafil, when given directly to the hypoxemic fetus, reverses reactive pulmonary vasoconstriction, increases left ventricular cardiac output by increasing pulmonary venous return, and ameliorates hypoxemic myocardial dysfunction. We used an instrumented sheep model. Fetuses were made hypoxemic over a mean (standard deviation) duration of 41.3 (9.5) minutes and then given intravenous sildenafil or saline infusion. Volume blood flow through ductus arteriosus was measured with an ultrasonic transit-time flow probe. Fetal left and right ventricular outputs and lung volume blood flow were calculated, and ventricular function was examined using echocardiography. Lung volume blood flow decreased and the ductus arteriosus volume blood flow increased with hypoxemia. There was a significant reduction in left ventricular and combined cardiac outputs during hypoxemia in both groups. Hypoxemia led to a reduction in myocardial isovolumic velocities, increased ductus venosus pulsatility, and reduced left ventricular myocardial deformation. Direct administration of sildenafil to hypoxemic fetus did not reverse the redistribution of cardiac output. Furthermore, fetal cardiac systolic and diastolic dysfunction was observed during hypoxemia, which was not improved by fetal sildenafil treatment. In conclusion, sildenafil did not improve pulmonary blood flow or cardiac function in hypoxemic sheep fetuses.Peer reviewe

Foramen ovale blood flow and cardiac function after main pulmonary artery occlusion in fetal sheep

The foramen ovale (FO) accounts for the majority of fetal left ventricular (LV) output. Increased right ventricular afterload can cause a redistribution of combined cardiac output between the ventricles. To understand the capability of the FO to increase its volume blood flow and thus LV output, we mechanically occluded the main pulmonary artery in seven chronically instrumented near-term sheep fetuses. We hypothesized that FO volume blood flow and LV output would increase during main pulmonary artery occlusion. Fetal cardiac function and haemodynamics were assessed by pulsed and tissue Doppler at baseline, 15 and 60 min after occlusion of the main pulmonary artery and 15 min after occlusion was released. Fetal ascending aorta and central venous pressures and blood gas values were monitored. Main pulmonary artery occlusion initially increased fetal heart rate (P <0.05) from [mean (SD)] 158 (7) to 188 (23) beats min(-1) and LV cardiac output (P <0.0001) from 629 (198) to 776 (283) ml min(-1). Combined cardiac output fell (P <0.0001) from 1524 (341) to 720 (273) ml min(-1). During main pulmonary artery occlusion, FO volume blood flow increased (P <0.001) from 507 (181) to 776 (283) ml min(-1). This increase was related to fetal tachycardia, because LV stroke volume did not change. Fetal ascending aortic blood pressure remained stable. Central venous pressure was higher (P <0.05) during the occlusion than after it was released. During the occlusion, fetal pH decreased and PCO2 increased. Left ventricular systolic dysfunction developed while LV diastolic function was preserved. Right ventricular systolic and diastolic function deteriorated after the occlusion. In conclusion, the FO has a limited capacity to increase its volume blood flow at near-term gestation.Peer reviewe

Low-dose aspirin therapy in IVF and ICSI patients

Abstract The first aim of this randomized, placebo-controlled and double-blind study was to investigate whether low-dose aspirin therapy, started prior to controlled ovarian hyperstimulation, improves ovarian stimulation response, uterine haemodynamics and clinical pregnancy rates in unselected patients who underwent in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). The second aim was to examine if the maternal serum placental proteome is different in IVF/ICSI pregnancies compared with spontaneous pregnancies, and whether low-dose aspirin modifies maternal serum placental protein expression and uteroplacental haemodynamics during the first half of pregnancy. Finally, the effect of low-dose aspirin therapy on the incidence of hypertensive pregnancy complications among women who became pregnant after IVF/ICSI was investigated. Low-dose aspirin therapy did not increase the number of oocytes retrieved, the total number of embryos or number of top-quality embryos, endometrial thickness or uterine haemodynamics on the day of embryo transfer (ET) or clinical pregnancy rates compared with placebo-treated IVF/ICSI women. On the day of ET, low-dose aspirin did not affect UtA vascular impedance, but the incidence of non-optimal uterine artery haemodynamics (UtA PI&#8805;3.0) was statistically significantly lower (p&#60;0.05) in the aspirin group compared with the placebo group. In the placebo-treated IVF/ICSI patients, maternal serum proteome analysis showed altered protein expression compared with women with spontaneous pregnancies. Between aspirin- and placebo-treated IVF/ICSI patients, proteome analysis showed a unique and distinct pattern of differentially expressed proteins including extra-cellular matrix, complement and transport proteins. At 6 weeks’ gestation, arcuate artery PI and at 18 weeks’ gestation, UtA PI values were lower (p&#60;0.05) in the aspirin group than in the placebo group. In conclusion, low-dose aspirin therapy, when started concomitantly with controlled ovarian hyperstimulation, did not improve ovarian responsiveness, uterine receptivity, pregnancy outcome in unselected IVF/ICSI women or affect UtA vascular impedance on the day of ET. Low-dose aspirin modified the early placentation process and reduced uteroplacental vascular impedance in mid-pregnancy, but did not decrease the incidence of hypertensive pregnancy complications.Tiivistelmä Keinoalkuisten hedelmöityshoitojen seurauksena keskimäärin reilu kolmannes naisista tulee raskaaksi hoitokertaa kohti. Näissä raskauksissa äidin seerumista määritettyjen istukkaperäisten merkkiaineiden pitoisuuksissa on eroavaisuuksia verrattuna spontaanisti raskaaksi tulleiden naisten seerumipitoisuuksiin ensimmäisen ja toisen raskauskolmanneksen aikana. Pre-eklampsian eli raskausmyrkytyksen riski on myös lisääntynyt. Syyksi arvellaan istukan verisuonipuuston poikkeavaa kehitystä. Pre-eklampsiaan liitetään intravaskulaarisen prostasykliinin ja tromboksaanin epätasapaino, joka johtaa verihiutaleiden aggregaation lisääntymiseen ja verisuonten supistumiseen. Matala-annoksinen asetyylisalisyylihappo (ASA) vähentää tromboksaanituotantoa ja korjaa tromboksaani- ja prostasykliinituotannon epätasapainoa, mutta sen ei ole todettu merkittävästi vähentävän näiden raskauskomplikaatioiden esiintyvyyttä edes riskiryhmillä, kun lääkitys on aloitettu toisen raskauskolmanneksen aikana. Tämän satunnaistetun ja plasebo-kontrolloidun kaksoissokkotutkimuksen tavoitteena oli tutkia keinoalkuisia hedelmöityshoitoja saavilla naisilla matala-annoksisen ASA-hoidon (100 mg/vrk) merkitystä munasarjojen stimulaatiovasteeseen, alkion kiinnittymiseen, istukan muodostumiseen ja kehittymiseen sekä lääkehoidon vaikutusta kohdun, istukan ja sikiön verenkiertoon, kun lääkitys aloitettiin munasarjojen stimulaatiohoidon alkaessa. Lisätavoitteena oli selvittää, onko lapsettomuushoitoja saavien naisten raskauksissa todettavissa spesifinen istukkaproteomiikkalöydös (istukan tuottamat valkuaisaineet) verrattuna spontaanisti raskaaksi tulleisiin naisiin ja voidaanko siihen vaikuttaa matala-annoksisella ASA-hoidolla. Toisena lisätavoitteena oli selvittää matala-annoksisen ASA-hoidon vaikutus pre-eklampsian esiintyvyyteen loppuraskaudessa. Matala-annoksinen asetyylisalisyylihappo (ASA) ei paranna keinoalkuisten hedelmöityshoitojen hoitotuloksia eikä vaikuta kohdun verenkiertoon tai kohdun limakalvon paksuuteen ultraäänellä arvioituna alkion siirtopäivänä. Matala-annoksista ASA-hoitoa käyttäneiden potilaiden ryhmässä todettiin kuitenkin merkitsevästi vähemmän naisia, joilla oli huonoa hoitotulosta keinoalkuisissa hedelmöityshoidoissa ennakoiva korkea molemminpuolinen kohtuvaltimoiden verenvirtausvastus alkion siirtopäivänä verrattuna plasebo-ryhmään. Raskaaksi tulleilla naisilla, jotka käyttivät matala-annoksista ASA-hoitoa, todettiin kohdun verenvirtausvastus matalammaksi alku- ja keskiraskaudessa verrattuna plasebo-ryhmän naisiin. Istukkaproteomiikkatutkimusten mukaan varhaisistukan proteiinituotanto on erilainen keinoalkuisissa raskauksissa verrattuna spontaanisti alkaneisiin raskauksiin ja siihen voidaan vaikuttaa matala-annoksisella ASA-hoidolla. Pre-eklampsian ja sikiön kasvunhidastuman esiintyvyydessä ei ryhmien välillä todettu eroa. Matala-annoksinen ASA-hoito aloitettuna ennen raskautta munasarjojen stimulaatiohoidon alkaessa ei paranna munasarjojen vastetta lapsettomuushoidoissa käytettäville hormonihoidoille, raskauslukuja eikä kohdun verenkiertoa alkion siirtopäivänä. Hoidon todettiin kuitenkin vaikuttavan varhaisistukan kehittymiseen sekä parantavan kohdun verenkierto alku- ja keskiraskaudessa viitaten istukan verisuonipuuston parempaan kehittymiseen. Matala-annoksinen ASA-hoito ei vähentänyt istukkaperäisten raskauskomplikaatioiden esiintymistä

Fetal cardiovascular hemodynamics in type 1 diabetic pregnancies at near‐term gestation

Abstract Introduction: Poor glycemic control in maternal type 1 diabetes mellitus during pregnancy can affect fetal cardiac and placental function. However, studies concerning fetal central hemodynamics have revealed conflicting results. We hypothesized that in pregnancies complicated by maternal type 1 diabetes, fetal cardiovascular and placental hemodynamics are comparable to the control fetuses at near‐term gestation. In addition, we investigated the relation between newborn serum biomarkers of cardiac function and fetal cardiovascular and placental hemodynamics. Furthermore, we studied whether maternal diabetes is associated with placental inflammation. Material and methods: In this prospective case‐control study, fetal central and peripheral hemodynamics were assessed by ultrasonography in 33 women with type 1 diabetes and in 67 controls with singleton pregnancies between 34+2 and 40+2 gestational weeks. Newborn umbilical cord serum was collected to analyze cardiac natriuretic peptides (atrial and B‐type natriuretic peptides) and troponin T concentrations. Placental tissue samples were obtained for cytokine analyses. Results: Fetal ventricular wall thicknesses were greater and weight‐adjusted stroke volumes and cardiac outputs were lower in the type 1 diabetes group than in the control group. Pulsatility in the aortic isthmus and inferior vena cava blood flow velocity waveforms was greater in the type 1 diabetes group fetuses than in the controls. A positive correlation was found between branch pulmonary artery and aortic isthmus pulsatility index values. Umbilical artery pulsatility indices were comparable between the groups. Umbilical cord serum natriuretic peptide and troponin T concentrations were elevated in the type 1 diabetes fetuses. These cardiac biomarkers correlated significantly with cardiovascular hemodynamics. Placental cytokine levels were not different between the groups. Conclusions: In maternal type 1 diabetes pregnancies, fetal cardiovascular hemodynamics is impaired. Maternal type 1 diabetes does not seem to alter placental vascular impedance or induce placental inflammation