Aortic isthmus doppler velocimetry in fetuses with intrauterine growth restriction: A literature review / Dopplervelocimetria do istmo aórtico em fetos com crescimento intrauterino restrito: Uma revisão da literatura

Abstract Intrauterine growth restriction (IUGR) is associated with poor perinatal prognosis and a higher risk of stillbirth, neonatal death, and cerebral palsy. Its detection and the evaluation of its severity by new Doppler velocimetric parameters, such as aortic isthmus (AoI), are of great relevance for obstetrical practice. The AoI is a vascular segment that represents a point of communication between the right and left fetal circulations. It is considered to be a functional arterial shunt that reflects the relationship between the systemic and cerebral impedances, and has recently been proposed as a tool to detect the status of hemodynamic balance and prognosis of IUGR in fetuses. In the present review, we noticed that in healthy fetuses, the AoI net flow is always antegrade, but in fetuses with IUGR the deterioration of placental function leads to progressive reduction in its flow until it becomes mostly retrograde; this point is associated with a drastic reduction in oxygen delivery to the brain. The more impaired the AoI flow is, the greater is the risk of impairment in the Doppler velocimetry of other vessels; and the alterations of the AoI Doppler seem to precede other indicators of severe hypoxemia. Although there seems to be an association between the presence of retrograde flow in the AoI and the risk of long-term neurologic disability, its role in the prediction of perinatal morbi-mortality remains unclear. The AoI Doppler seems to be a promising tool in the management of fetuses with IUGR, but more studies are needed to investigate its employment in clinical practice.

Resumo O crescimento intrauterino restrito (CIUR) está associado a um prognóstico perinatal adverso, com maior risco de óbito intrauterino e neonatal, bem como de paralisia cerebral. Assim, sua detecção e a determinação de sua gravidade por novos parâmetros Dopplervelocimétricos, como o istmo aórtico (IAo), são de fundamental importância na prática obstétrica. O IAo é um segmento vascular que representa um ponto de comunicação entre os sistemas circulatórios fetais esquerdo e direito. É considerado um shunt arterial funcional, capaz de refletir a relação entre as impedâncias dos circuitos cerebral e sistêmico, e foi proposto como uma ferramenta para detecção do status do equilíbrio hemodinâmico e do prognóstico de fetos com CIUR. Na presente revisão, observou-se que, em fetos saudáveis, o fluxo predominante no IAo é sempre anterógrado; mas em fetos com CIUR a deterioração do estágio de insuficiência placentária acarreta reduções progressivas no fluxo ístmico até este apresentar sentido predominantemente retrógrado e levar a uma drástica redução no aporte de oxigênio ao sistema nervoso central. Quanto mais alterado estiver o fluxo no IAo, maior a chance de haver alteração na Dopplervelocimetria de outros vasos; e as alterações no Doppler do IAo parecem preceder outros indicadores de hipoxemia severa. Embora o fluxo retrógrado no IAo pareça se correlacionar com maior risco de alteração no desenvolvimento neurológico a longo prazo, ainda não está claro o seu papel na predição de morbimortalidade perinatal. O Doppler do IAo parece ser um parâmetro promissor no manejo do CIUR; entretanto, mais estudos são necessários para avaliar seu emprego na prática clínica.

Cerebroplacental ratio and aortic isthmus systolic index in evaluation on pregnancy outcome of late-onset fetal growth restriction / 中国介入影像与治疗学

Objective: To explore the value of cerebroplacental ratio (CPR) and aortic isthmus systolic index (ISI) in evaluation on pregnancy outcome of late-onset fetal growth restriction (FGR). Methods: Totally 88 pregnant women with clinically confirmed late-onset FGR were retrospectively analyzed, among them 39 had poor pregnancy outcomes (case group) and 49 had good pregnancy outcomes (control group). CPR and ISI of fetuses were compared between 2 groups. ROC curve was used to analyze the value of CPR and ISI in predicting fetal pregnancy outcomes. Results: CPR and ISI of case group were lower than those of control group (both P<0.01). ROC curve results showed that taken 1.25 as the cut-off value of CPR, the sensitivity and specificity of adverse pregnancy outcome was 82.1% and 59.7%, respectively, and AUC was 0.814; while taken -0.44 as the cut-off value of CPR, the sensitivity, specificity and AUC was 94.9%, 82.7% and 0.930, respectively. Conclusion: Both CPR and ISI had predictive value for fetal adverse pregnancy outcome of late-onset FGR, and ISI was superior to CPR.

Research progresses of hemodynamics in aortic isthmus of fetuses during the second and third trimester / 中国医学影像技术

The aortic isthmus (AOI) connects the blood circulation of fetal supraphrenic and subphrenic organs,reflecting fetal blood distribution directly and quickly.The waveform of AOI can demonstrate the fetal blood supply,the presence of intrauterine hypoxia and so on.Measurement of fetal AOI Doppler spectrum and related hemodynamic parameters may provide reliable indicators for early detection and positive intervention in fetal growth retardation,which is of great significance for increasing the detection rate of FGR and reducing the incidence and mortality of perinatal period.The research progresses of hemodynamics in AOI of fetuses during the second and third trimester were reviewed in this article.

Research progresses of hemodynamics in aortic isthmus during fetal period / 中国医学影像技术

In the fetal circulation,the right and left cardiovascular system are positioned in parallel,and the aortic isthmus behaves as a shunt that connecting both up-and downstream circulations,allowing the fetuses to increase or reduce the amount of blood directed to the brain and heart depending on the degree of oxygen supply from the placenta.Doppler blood flow waveform of the fetal aortic isthmus can be obtained from the traditional longitudinal aortic arch view or the more recently described three vessels and trachea view of the fetal upper mediastinum.The aortic isthmus blood flow has a characteristic shape with end-systolic notch during the third trimester pregnancy and gradually deepen with the increase of gestational age.Doppler blood flow waveform of the aortic isthmus is closely related to fetal brain and heart function,and its reverse signal in the diastolic phase shows the poor intrauterine fetus.

Study on flow states in normal fetal aortic isthmus by echocardiography / 中华超声影像学杂志

Objective To explore blood flow characteristics of normal fetal aortic isthmus (AoI) in different gestational age by fetal echocardiography.Methods Two hundred and sixty-five normal fetuses were enrolled in the study from August 2015 to July 2016.The mean gestational age was (29.35 ± 4.50) weeks,The AoI inner diameter(D),systolic and diasctolic as well as end-systolic velocities (v),end-systolic duration time(t),pulsatility index(PI),resistance index (RI) were measured.The relationship between these parameters and gestational age was plotted by linear regression.Results In normal fetues,there was a short reverse flow at the end of systole and these states could be classified into three categories by gestational weeks(GW):(1) line-like wave (P50 =25.55 GW);(2) incisura wave (P50 =30.10 GW);(3) reverse flow (P50 =35.40 GW).There were good correlation between end systolic v and gestational age (R =0.786,P ＜0.05),as well as D and gestational age(R =0.726,P ＜0.05).The correlation between end systolic t and gestional age was moderate (R =0.518,P ＜0.05).Conclusions A short reverse flow can be the characteristics of normal fetal aortic isthmus,and the end systolic flow increases significantly with the gestational age.These characteristics can provide differential information for abnormal blood flow states.

EFFECTIVENESS EVALUATION OF THORACIC ENDOVASCULAR AORTIC REPAIR FOR BLUNT THORACIC AORTIC INJURY WITH HOSTILE STENT-GRAFT PROXIMAL LANDING ZONE / 中国修复重建外科杂志

OBJECTIVE: To explore the effectiveness of thoracic endovascular aortic repair (TEVAR) for blunt thoracic aortic injury (BTAI) with hostile stent-graft proximal landing zone. METHODS: A retrospective analysis was made on the clinical data of 13 patients with BTAI with hostile stent-graft proximal landing zone treated by TEVAR between December 2007 and December 2014. There were 10 males and 3 females with the mean age of 44 years (range, 24-64 years). The imaging examination indicated Stanford type B aortic dissection in 7 cases, pseudoaneurysm in 3 cases, aneurysm in 1 case, and penetrating ulcer in 2 cases. According to the partition method of thoracic aortic lesion by Mitchell, 8 cases underwent stent-graft with left subclavian artery (LSA) coverage, 3 underwent chimney stents for LSA, and 2 for left common carotid artery (LCCA). In 2 cases receiving chimney TEVAR involving LCCA, one underwent steel coils at the proximal segment of LSA to avoid type II endoleak and the other underwent in situ fenestration for endovascular reconstruction of LSA. RESULTS: All TEVAR procedures were successfully performed. The mean operation time was 1.8 hours (range, 1-3 hours); the mean intraoperative blood loss was 120 mL (range, 30-200 mL); and the mean hospitalization time was 15 days (range, 7-37 days). No perioperative death and paraplegia occurred. The patients were followed up 3-30 months (mean, 18 months). Type I endoleak occurred in 1 case during operation and spontaneously healed within 6 months. Hematoma at brachial puncture site with median nerve compression symptoms occurred in 1 case at 3 weeks after operation; ultrasound examination showed brachial artery pseudoaneurysm and thrombosis, and satisfactory recovery was obtained after pseudoaneurysmectomy. No obvious chest pain, shortness of breath, left upper limbs weakness, numbness, and dizziness symptoms were observed. Imaging examination revealed that stentgraft and branched stent remained in stable condition. Meanwhile the blood flow was unobstructed. No lesions expanded and ruptured. No new death, bacterial infection, or other serious complications occurred. CONCLUSIONS: According to Mitchell method, individualized plan may be the key to a promising result. More patients and further follow-up need to be included, studied, and observed.

The Clinical Value of Measurement of Normal Fetal Aortic Isthmus Systolic Index with Prenatal Ultrasound / 中国医科大学学报

Objective To obtain the fatal aortic isthmic systolic index(ISI)with prenatal ultrasound,and to establish reference ranges for normal live fatal aortic isthmic systolic index(ISI). Methods A total of 251 normal fetuses at 18?37 gestation weeks were collected and underwent Dop?pler ultrasound examination to obtain the fatal aortic isthmus waveforms. Peak systolic velocity(PSV)and systolic nadir(NS)were measured on the waveforms. ISI was derived from the ratio NS/PSV,and its relationship with gestational weeks was analyzed. Results ISI value was between 0.19 and 0.21,from 18 to 24 gestational weeks. As the gestational weeks increasing,PSV increased;however,NS decreased gradually. At about 28 weeks,a brief end?systolic deceleration wave was observed on the aortic isthmus waveforms,and this trend led to ISI towards a mean value of zero at about 30 weeks. At the end of pregnancy,ISI was about-0.33. The curve equations were established regarding the gestational age as the independent variable X,PSV,NS and ISI as the dependent variable Y respectively. Y∧=-69.116+9.542X-0.139X2,R2=0.96,P<0.001;Y∧=-99.881+10.331X-0.232X2,R2=0.99,P<0.001;Y∧=-0.671+0.086X-0.02X2,R2=0.99,P<0.001. Conclusion Prenatal ultrasound can measure the fetal aortic isthmic systolic index,which is helpful in the diagnosis of fetal cardiovascular anomalies and evaluation of fetal intrauterine status.

Doppler assessment of fetal aortic isthmus flow in twin

OBJECTIVE: The purpose of this study was to investigate the aortic isthmus (AoI) flow difference between larger fetus and smaller fetus of twin; and to evaluate the predictive value of early diagnosis of hemodynamic change in twin growth. METHODS: This prospective study on 49 pairs of twin fetuses was performed to obtain AoI blood flow data. Cases with structural or chromosomal abnormalities and co-twin death were excluded. The interval from examination to delivery was within 4 weeks and 3 cases over 4 weeks interval were re-examined. Assessment of fetal AoI Doppler parameters were peak systolic velocity (PSV), end-diastolic velocity, times-averaged maximum velocities, pulsatility index (PI), and resistance index (RI). According to the direction of the diastolic flow in the AoI, antegrade and retrograde flow were made and was used to analyze the perinatal outcomes of each fetus. The predictive value of AoI Doppler parameters in predicting fetal growth was obtained by using ANOVA and logistic regression analysis of quantitative variables in each fetus of twins. RESULTS: There were significant differences in the gestational weeks at delivery, birth weight and the incidence of growth discordance over 20% or more between monochorionic twin and dichorionic twin. The AoI PI and RI were significantly higher in smaller fetus than in larger regardless of chorionicity. Retrograde flow was noted in 8 of 98 cases (8.2%) and the only one case was of the larger fetus and the others were smaller fetuses of twin. Significant correlations were found between the AoI PI and birthweight (P=0.018) and between the PSV and growth discordance (P=0.032). In monochorionic twin, linear correlation was shown between the AoI PI and birthweight (P=0.004) and between AoI PI and growth discordance (P=0.031). Also, the meaningful correlation between the PSV and birthweight (P=0.036) was found by using logistic regression analyses. CONCLUSION: On the basis of our observation, AoI PI has revealed their hemodynamic status and this result may improve the understanding of growth patterns in twins.

Successful Repair of a Traumatic Aortic Isthmus Pseudoaneurysm Concomitant with Right Diaphragmatic Hernia / 日本心臓血管外科学会雑誌

A 24-year-old woman underwent successful repair of a traumatic pseudoaneurysm of the aortic isthmus concomitant with right diaphragmatic hernia which developed after a traffic accident, and the steering wheel of the crashed car was considered responsible for both lesions. Due to the right diaphragmatic hernia, she could breathe mainly with the left lung only. The aortic isthmus aneurysm was considered to be a pseudoaneurysm, and because of the potential risk of rupture, we performed urgent aortic surgery. Prior to a left thoracotomy, we anastomosed an 8-mm prosthetic graft to the right axillary artery. When the left lung was collapsed in order to perform a femoro-femoral bypass, the SpO₂ level of her right index finger and her cerebral rSO₂ markedly decreased. Therefore, we administered additional perfusion via the right axillary artery, which provided sufficient oxygen to the upper body and brain. The patient underwent Marlex mesh reinforcement of the right diaphragmatic hernia 30 days after grafting, and is doing well 1 year postoperatively.

Evaluación de la función cardiovascular en fetos con restricción de crecimiento / Cardiac function in fetus with growth restriction

Objective: To evaluate longitudinal changes in the cardiac function parameters in relation to the hemodynamic worsening in growth restricted (IUGR) fetuses. Methods: The cardiac function was serially studied in a cohort of 46 IUGR fetuses below 32 weeks of gestation by 2-D and Doppler ultrasound parameters. IUGR was defined as an estimated fetal weight below the 10th percentile with a Doppler pulsatility index (PI) in the umbilical artery (UA) above 2 standard deviations of the mean. Longitudinal changes, perinatal deaths and survivors were evaluated. Results: All cardiac parameters were significantly different in IUGR fetuses. Aortic isthmus blood flow index (IFI) and Modified myocardial performance index (Mod-MPI) showed the clearest longitudinal changes and temporal deterioration. Conclusions: IFI and Mod-MPI showed consistent longitudinal changes in IUGR fetuses. These 2 markers could be added to the DV to evaluate the fetal deterioration and indicate the optimal time of delivery.

Objetivo: Evaluar cambios longitudinales de los parámetros de función cardíaca en relación al agravamiento hemodinámico en fetos con restricción del crecimiento intrauterino (RCIU). Métodos: La función cardíaca fue estudiada en una cohorte de 46 fetos RCIU con menos de 32 semanas de gestación con parámetros 2-D y ultrasonografía Doppler. Se definió RCIU como un peso fetal estimado bajo el percentil 10 asociado a un índice de pulsatilidad (IP) al Doppler de la arteria umbilical (AU) por debajo de dos desviaciones estándar del promedio. Se evaluaron cambios longitudinales, mortalidad y sobrevida perinatal. Resultados: Todos los parámetros tuvieron diferencias estadísticamente significativas en fetos RCIU. El índice de velocidad de flujo del istmo aórtico (IFI) y el índice de función miocárdico modificado (IFM-mod) mostraron los más evidentes cambios longitudinales y deterioro en el tiempo. Conclusiones: El IFI y el IFM-mod mostraron consistentes cambios longitudinales en fetos RCIU. Estos dos marcadores podrían ser usados junto a la medición del ductus venoso para evaluar el deterioro fetal y la indicación óptima del momento del parto.