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Dive into the research topics where Katsusuke Ozawa is active.

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Featured researches published by Katsusuke Ozawa.


Prenatal Diagnosis | 2016

Forty cases of twin reversed arterial perfusion sequence treated with radio frequency ablation using the multistep coagulation method: a single-center experience.

Rika Sugibayashi; Katsusuke Ozawa; Masahiro Sumie; Seiji Wada; Yushi Ito; Haruhiko Sago

To report the pregnancy outcomes of patients with twin reversed arterial perfusion (TRAP) sequence treated by radiofrequency ablation (RFA).


Fetal Diagnosis and Therapy | 2011

Congenital omphalocele and polyhydramnios: a study of 52 cases.

Katsusuke Ozawa; Hiroshi Ishikawa; Yasuyo Maruyama; Tomoko Nagata; Hiromi Nagase; Yasufumi Itani; Kenji Kurosawa; Michiko Yamanaka

Introduction: Unlike gastroschisis, congenital omphalocele is often associated with other anomalies and is frequently complicated by polyhydramnios. We examined the relationships between polyhydramnios, pregnancy outcome and fetal prognosis.Patients and Methods: Clinical data from cases diagnosed antenatally with congenital omphalocele from 1993 to 2006 were analyzed retrospectively. Results: Fifty-two cases were diagnosed antenatally with congenital omphalocele, and 38 of these pregnancies resulted in delivered infants. Of these 38 pregnancies, 55.3% were preterm births before 37 weeks of gestation. The mean birth weight was 2,148 g (n = 38). Associated anomalies were recognized in 29 cases (76.3%), including 13 cases (34.2%) of chromosomal aberrations. There were 2 cases of trisomy 13, 10 cases of trisomy 18 and 1 case of trisomy 21. Polyhydramnios was detected in 14 cases (36.8%), and other anomalies were present in all of these cases. Discussion: For antenatal evaluation in cases of congenital omphalocele, it is important to examine the fetus for associated anomalies or underlying disease, especially when polyhydramnios is detected.


Ultrasound in Medicine and Biology | 2015

Measurement of internal diameter changes and pulse wave velocity in fetal descending aorta using the ultrasonic phased-tracking method in normal and growth-restricted fetuses.

Susumu Miyashita; Jun Murotsuki; Jin Muromoto; Katsusuke Ozawa; Nobuo Yaegashi; Hideyuki Hasegawa; Hiroshi Kanai

Phased tracking (PT) is an ultrasound-based technique that enables precise measurement of a target velocity. The aims of this study were to use PT to evaluate arterial pulse waveform, pulse wave velocity and fetal pulse pressure in normal and growth-restricted fetuses. One hundred fetuses with normal development and 15 fetuses with growth restriction were analyzed. Ultrasonic raw radiofrequency signals were captured from a direction perpendicular to the vascular axis at the fetal diaphragmatic level for the difference in internal dimensions (DID), or simultaneously from different directions for the pulse wave velocity. Pulsatile movement of the proximal and distal intima of the vessels was analyzed using PT. The fetal DID exhibited no significant changes in growth-restricted fetuses. Pulse wave velocity (3.8 ± 0.32 m/s vs. 2.2 ± 0.069 m/s, p < 0.001) and estimated pulse pressure (6.9 ± 0.90 kPa vs. 2.5 ± 0.18 kPa, p < 0.001) were significantly elevated in growth-restricted fetuses. Assessment of DID and pulse wave velocity of the descending aorta using PT is a feasible, non-invasive approach to evaluation of fetal hemodynamics.


Fetal Diagnosis and Therapy | 2015

Assessing Fetal Cardiac Function by Measuring Myocardial Radial Velocity Using the Phased-Tracking Method

Katsusuke Ozawa; Jun Murotsuki; Susumu Miyashita; Jin Muromoto; Hideyuki Hasegawa; Hiroshi Kanai; Nobuo Yaegashi

Objective: This study aimed to assess the cardiac function of healthy and pathological fetuses by measuring radial velocity using phased tracking (PT). Based on phase differences, PT allows the displacement of a specified point to be detected with improved spatial and temporal resolution. Methods: PT was used to assess cardiac radial velocity in the basal free wall of the left and right ventricles in 134 healthy fetuses, 10 second-trimester intrauterine growth-restricted (IUGR) fetuses, and 10 recipient twins with twin-to-twin transfusion syndrome (TTTS). Maximum velocities were measured in systole and early diastole. Results: Maximum radial velocity was successfully measured in 126 healthy fetuses (94%) at gestational ages of 16-40 weeks. Systolic and early diastolic maximum velocities increased with gestational age in both ventricles. As compared with controls, IUGR fetuses had significantly lower early diastolic maximum velocities in the right ventricle, and recipient twins with TTTS had significantly lower systolic and early diastolic maximum velocities in both ventricles. Conclusions: PT demonstrated right ventricular diastolic dysfunction in second-trimester IUGR fetuses as well as systolic and diastolic dysfunctions in both ventricles in recipient twins with TTTS. PT could be useful for evaluating fetal cardiac radial function.


Journal of Obstetrics and Gynaecology Research | 2016

Significance of oligohydramnios in preterm small-for-gestational-age infants for outcome at 18 months of age

Jun Sasahara; Keisuke Ishii; Nagayoshi Umehara; Mari S. Oba; K. Kiyoshi; Takeshi Murakoshi; Tomohiro Tanemoto; Hiroshi Ishikawa; Kiyotake Ichizuka; Aya Yoshida; Kei Tanaka; Katsusuke Ozawa; Haruhiko Sago

The aim of this study was to evaluate the association between oligohydramnios and other perinatal factors in preterm small‐for‐gestational‐age (SGA) infants who had cerebral palsy at 18 months of age or who had died before this age.


Journal of Obstetrics and Gynaecology Research | 2017

Fetoscopic laser photocoagulation for amniotic fluid discordance bordering on twin–twin transfusion syndrome: Feasibility, perinatal and long-term outcomes

Katsusuke Ozawa; Rika Sugibayashi; Seiji Wada; Masahiro Sumie; Keisuke Ishii; Masahiko Nakata; Takeshi Murakoshi; Yushi Ito; Haruhiko Sago

This study investigated the feasibility and safety of fetoscopic laser photocoagulation (FLP) for amniotic fluid discordance (AFD) bordering on twin–twin transfusion syndrome (TTTS) with an absent or reverse end‐diastolic velocity (AREDV) in the umbilical artery (UA), and evaluated the perinatal and long‐term outcomes.


Journal of Obstetrics and Gynaecology Research | 2018

Fetoscopic laser photocoagulation for twin–twin transfusion syndrome

Haruhiko Sago; Keisuke Ishii; Rika Sugibayashi; Katsusuke Ozawa; Masahiro Sumie; Seiji Wada

The aim of this study was to review fetoscopic laser photocoagulation (FLP), which ablates placental vascular anastomoses to treat twin–twin transfusion syndrome (TTTS). A review of studies reporting on the procedures, outcomes, complications and nonconventional applications of FLP for TTTS was conducted. FLP has been established as the primary treatment for monochorionic twin pregnancy associated with TTTS at 16–26 weeks. FLP is the only therapy that directly addresses the underlying pathophysiology. The recent technique modification of FLP, referred to as the ‘Solomon technique’, induces selective coagulation to connect the anastomoses ablation sites and has been introduced to reduce residual anastomoses. The perinatal survival following FLP improved significantly with advances in the technique after its introduction. The recent survival rates of both twins and at least one twin are 70% and more than 90%, respectively. However, there is still an 11–14% risk of long‐term neurodevelopment impairment. The premature rupture of membranes that leads to preterm labor is a common complication after FLP. FLP is a valuable treatment option for feto‐fetal transfusion syndrome in triplets and for TTTS after 26 weeks. FLP for selective intrauterine growth restriction may be potentially beneficial when accompanied by abnormal Doppler findings and oligohydramnios. FLP is the optimal treatment option for TTTS at 16–26 weeks of gestation. FLP appears to be applicable in triplets, TTTS after 26 weeks and cases of selective intrauterine growth restriction with abnormal Doppler findings and oligohydramnios. FLP is the most common and successful fetal intervention. Improvement in the neurodevelopmental outcomes after FLP is a future focus.


Journal of Obstetrics and Gynaecology Research | 2018

Fetal lung size after thoracoamniotic shunting reflects survival in primary fetal hydrothorax with hydrops

Fumio Suyama; Katsusuke Ozawa; Kohei Ogawa; Rika Sugibayashi; Seiji Wada; Haruhiko Sago

To assess the role of lung size and abnormal Doppler findings in the umbilical artery (UA) in determining the outcomes of fetuses with primary fetal hydrothorax (FHT) associated with hydrops who underwent thoracoamniotic shunting (TAS).


Journal of Obstetrics and Gynaecology Research | 2018

Stomach herniation prior to nonreassuring fetal status in a case of fetal gastroschisis

Yuki Kojima; Katsusuke Ozawa; Rika Sugibayashi; Seiji Wada; Haruhiko Sago

The neonatal prognosis in gastroschisis is generally good; however, intrauterine fetal death (IUFD) and nonreassuring fetal status (NRFS) sometimes occur in fetal cases of gastroschisis. Previously, we reported stomach herniation as a possible risk factor for IUFD or NRFS in fetuses with gastroschisis. We report a case of fetal gastroschisis showing stomach herniation and increased velocity of the umbilical venous (UV) flow the day before NRFS by electronic fetal monitoring (EFM). A 27‐year‐old pregnant woman was followed up from 16 weeks’ gestation due to fetal gastroschisis. At 33 + 1 weeks’ gestation, EFM displayed a reassuring fetal state, while the ultrasound examination revealed fetal stomach herniation and an increased flow velocity of the UV in the abdomen. One day later, EFM displayed NRFS, and the patient underwent emergency caesarean section. This case showed stomach herniation preceding the occurrence of NRFS. Stomach herniation may be a predictor of NRFS in fetuses with gastroschisis.


Journal of Perinatal Medicine | 2017

A poor long-term neurological prognosis is associated with abnormal cord insertion in severe growth-restricted fetuses

Masamitsu Nakamura; Nagayoshi Umehara; Keisuke Ishii; Jun Sasahara; Kenji Kiyoshi; Katsusuke Ozawa; Kei Tanaka; Tomohiro Tanemoto; Kiyotake Ichizuka; Junichi Hasegawa; Hiroshi Ishikawa; Takeshi Murakoshi; Haruhiko Sago

Abstract Objective: To clarify and compare if the neurological outcomes of fetal growth restriction (FGR) cases with abnormal cord insertion (CI) are associated with a higher risk of a poor neurological outcome in subjects aged 3 years or less versus those with normal CI. Methods: A multicenter retrospective cohort study was conducted among patients with a birth weight lower than the 3rd percentile, based on the standard reference values for Japanese subjects after 22 weeks’ gestation, who were treated at a consortium of nine perinatal centers in Japan between June 2005 and March 2011. Patients whose birth weights were less than the 3rd percentile and whose neurological outcomes from birth to 3 years of age could be checked from their medical records were analyzed. The relationship between abnormal CI and neurological outcomes was analyzed. Univariate and multivariate models of multivariate logistic regression were employed to estimate the raw and odds ratio (OR) with 95% confidence intervals comparing marginal (MCI) and velamentous cord insertion (VCI) to normal CI. Results: Among 365 neonates, 63 cases of MCI and 14 cases of VCI were observed. After excluding 24 cases with neonatal or infant death from the total FGR population, the assessment of the outcomes of the infants aged 3 years or younger showed the following rates of neurological complications: 7.3% (n=25) for cerebral palsy, 8.8% (n=30) for developmental disorders, 16.7% (n=57) for small-for-gestational-age short stature (SGA), 0.6% (n=2) for impaired hearing, 0.9% (n=3) for epilepsy, 1.2% (n=4). The ORs (95% confidence intervals) based on multivariate analysis were as follows: cerebral palsy=10.1 (2.4–41.5) in the VCI group and 4.3 (1.6–11.9) in the MCI group, developmental disorders=6.7 (1.7–26) in the VCI group and 3.9 (1.1–14.2) in the single umbilical artery (SUA) group, 5.1 (1.4–18.7) for birth weight <1000 g and 2.8 (1.2–6.7) for placental weight <200 g. Conclusions: The present results indicate that growth-restricted fetuses diagnosed with a birth weight below the 3rd percentile exhibiting abnormal umbilical CI are at a high risk for poor neurological outcomes, including cerebral palsy and/or developmental disorders.

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Seiji Wada

Jikei University School of Medicine

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Tomohiro Tanemoto

Jikei University School of Medicine

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