K Hecher

University Medical Center Hamburg - Eppendorf, Hamburg, Hamburg, Germany

Are you K Hecher?

Claim your profile

Publications (272)1081.48 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this study was to evaluate the phenomenon of vascular ischemic limb necrosis in twin-twin transfusion syndrome (TTTS). This was a multicenter retrospective review of ischemic limb necrosis in patients with TTTS. Twenty cases of fetal ischemic limb necrosis in association with TTTS were identified from 10 fetal medicine centers. The recipient was affected in 19 cases, and the lower limb was affected in 17 cases. The extent of the damage correlated with TTTS severity. Eighty percent of limb defects (16/20) clearly were unrelated to laser treatment (3 cases untreated, 7 cases after amnioreduction, 6 cases present at time of laser). The recipient was relatively polycythemic in 5 of 7 cases in which neonatal or fetal hemoglobin/hematocrit levels were available. Ischemic limb necrosis is a rare complication of TTTS. The lesion is unrelated to therapy and may be the result of polycythemia, hypertension, and vasoconstriction.
    No preview · Article · Aug 2012 · American journal of obstetrics and gynecology
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate time intervals of ductus venosus (DV) flow velocity waveforms (FVW) in correlation to fetal heart rate and gestational age and to construct reference ranges for the second and third trimester. Furthermore, we investigate time intervals of FVW through the tricuspid valve. Flow velocity waveforms of the DV and through the tricuspid valve were recorded in 135 normal singleton fetuses between 17 and 38 weeks' gestation. Time intervals for systolic (S) and early diastolic (D) peaks were analyzed regarding acceleration time (acc-S for S, acc-D for D) and deceleration time (dec-S for S, dec-D for D), respectively. Similarly, time intervals for both peaks of right ventricular inflow were analyzed regarding acceleration time (acc-E for E-wave, acc-A for A-wave) and deceleration time (dec-E for E-wave, dec-A for A-wave), respectively. In the DV, acc-D and dec-D increased significantly with gestational age. In tricuspid valve, acc-E and acc-A showed a significant increase with gestational age. All parameters except acc-S showed significant negative correlations with fetal heart rate. With advancing gestational age, prolongation of the diastolic phase of DV-FVW and of the E-wave of tricuspid flow was observed, suggesting maturation of ventricular diastolic function. Time-related analysis of Doppler signals of DV-FVW may provide detailed insights into fetal cardiac function.
    No preview · Article · Aug 2012 · Prenatal Diagnosis
  • [Show abstract] [Hide abstract]
    ABSTRACT: We assessed vascular programming in genetically identical monochorionic twin pairs with twin-to-twin transfusion syndrome (TTTS) treated differently in utero by serial amnioreduction or fetal laser arterial photocoagulation. This case–control study re-assessed four twin groups at median 11 years comprising 20 pairs of monochorionic diamniotic twins: nine treated by amnioreduction (TTTS-amnio) and eleven by laser (TTTS-laser) with seven monochorionic and six dichorionic control pairs. Outcome measures were current blood pressure (BP), brachio-radial arterial stiffness derived from pulse wave velocity (PWV), resting microcirculation (Flux) and response to heating and post-occlusive reactive hyperaemia measured using laser Doppler. Potential confounders [PWV and BP at first study, current height, weight, heart rate and twin type (ex-recipient, ex-donor or heavier/lighter of pair)] were accounted for by Mixed Linear Models statistical methodology. PWV dichorionic > monochorionic (P = 0.024); systolic and diastolic BP dichorionic > TTTS-amnio and TTTS-laser (P = 0.004, P = 0.02 and P = 0.005, P = 0.02, respectively). Within-twin pair pattern of PWV discordance was similar in laser treated and dichorionic controls (heavier-born > lighter), opposite to TTTS-amnio and monochorionic controls. Flux monochorionic > dichorionic (P = 0.044) and heavier > lighter-born (P = 0.024). TTTS-laser and dichorionic diamniotic showed greatest hyperaemic responses (dichorionic > TTTS-amnio or monochorionic controls (P = 0.007, P = 0.025). Hyperaemic responses were slower in heavier-born twins (P = 0.005). In summary, monochorionic twins had lower BP, arterial stiffness and increased resting vasodilatation than dichorionic twins implying shared fetal circulation affects vascular development. Vascular responses in laser-TTTS were similar to dichorionic and opposite to TTTS-amnio suggesting a lasting effect of fetal therapy on vascular health.
    No preview · Article · Jun 2012 · Journal of Developmental Origins of Health and Disease
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate MRI of the fetal heart by way of a novel triggering method with the use of an MR-compatible cardiotocography (CTG) in an animal model. Fetal cardiac MRI was performed on four pregnant ewes on a 1.5 Tesla (T) MR system. A CTG was rendered MR compatible and its signal was used for the triggering of the fetal heart to perform cardiac cine MRI of the fetal heart with maternal free-breathing with cine steady-state free precession. The left ventricular volume and function were measured from the short-axis (view). The image quality of anatomical structures was assessed. All cardiac valves and the foramen ovale could be visualized. Myocardial contraction was depicted in cine sequences. The average blood volume at the end systole was 1.7 mL (SD ± 0.12). The average volume at the end diastole was 4.6 mL (± 0.4); thus the average stroke volumes of the left ventricle were 2.87 mL (± 0.31) with ejection fractions of 60.53% (± 4.17). The newly developed MR compatible CTG could be used as a tool for cardiac triggering method of the fetal heart. This novel device might help fetal cardiac MRI technology in the future.
    No preview · Article · May 2012 · Journal of Magnetic Resonance Imaging
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Uterine natural killer (NK) cells are pivotal for successful mammalian reproduction. However, insights on functionally distinct subpopulations of uterine NK cells are largely elusive. Furthermore, translation of findings from murine into human pregnancy has been overshadowed by the limited number of mutual phenotypic NK cell markers. We here provide evidence that a subset of murine mature NK (mNK) cells present at the feto-maternal interface, identified as CD27(low)DX5(+)CD3(neg), is pivotal in maintaining pregnancy. This mNK subset has low cytotoxic capacity, produces higher amounts of interferon (IFN)-γ, and expresses functional homologs of human NK cell immunoglobulin-like receptors. We further show that bone marrow-derived CD27(low) mNK cells are selectively recruited to the uterus and ameliorate the rate of fetal loss when adoptively transferred into alymphoid RAG2(-/-)/γc(-/-) mice. Additionally, expression of CD27 is down-modulated on mNK cells upon migration to the uterus. Hence, we propose the existence of a regulatory mNK cell subset, which is licensed toward successful pregnancy maintenance at the fetomaternal interface in mice. As CD27(low) NK cells are also present in human decidua, the CD27(low) NK subset may provide a tool to foster translational research in reproduction, aiming to improve pregnancy outcome in humans.
    Full-text · Article · Feb 2012 · Journal of Molecular Medicine
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate intrauterine balloon tamponade with or without B-Lynch sutures in avoiding postpartum hysterectomy in cases with severe postpartum hemorrhage. Retrospective analysis using all women delivering between January 2005 and July 2010 in our center. Prevention of hysterectomy was the main outcome studied. Twenty-four cases of severe postpartum hemorrhage occurred in which medical treatment alone failed. In 20 cases, the Bakri balloon was the first choice to stop hemorrhage. Sixty percent (n = 12) of these were successfully treated with the balloon alone, 30% (n = 6) with the balloon and the B-Lynch suture. Therefore, 90% (n = 18) were successfully treated with the balloon as part of the treatment. The balloon tamponade was not successful in 2 cases. Four cases were treated with emergency hysterectomy a priori. The Bakri balloon with or without B-Lynch sutures in a stepwise approach is an effective option for the treatment of severe PPH.
    Full-text · Article · Jan 2012 · American journal of obstetrics and gynecology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Asymmetric dimethylarginine (ADMA) is a key regulator of nitric oxide production. Elevations of ADMA have previously been associated with endothelial dysfunction in pre-eclamptic women. ADMA is degraded mainly by dimethylarginine dimethylaminohydrolase (DDAH), which is also expressed in placental tissue. Therefore, we measured placental DDAH expression and activity in pre-eclampsia and normal pregnancies in order to determine whether impairment of this enzyme in the pre-eclamptic placenta could contribute to elevations of ADMA levels in these women. ADMA plasma levels were measured by LC-MS/MS in 18 pre-eclamptic patients and 28 controls. Placental DDAH activity was determined by measuring the degradation of [(2)H(6)]-labeled ADMA in tissue homogenates from placental biopsies in 15 women with pre-eclampsia and 16 controls. Placental mRNA expression of DDAH 1, DDAH 2, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and protein-arginine methyltransferase 1 (PRMT1) was determined in tissue biopsies by RT-PCR. Placental DDAH activity was almost undetectable in pre-eclampsia, and it was significantly higher in controls. ADMA plasma levels were higher in pre-eclampsia as compared to normal pregnancies (0.51±0.15μmol/l vs. 0.42±0.07μmol/l; p=0.005), and the difference between maternal and fetal ADMA levels (feto-maternal ADMA gradient) was lower in pre-eclampsia (0.63±0.20μmol/l vs. 0.80±0.18μmol/l; p=0.02). Furthermore, mRNA expression levels of DDAH 2 were significantly lower in pre-eclamptic women (p=0.04), while PRMT1 expression levels were the same. In pre-eclampsia, we found only weak correlations between maternal ADMA levels and DDAH 1 (r=-0.41; p=0.22) and DDAH 2 expressions (r=-0.45; p=0.17) but a slightly stronger correlation between DDAH 2 expression and feto-maternal ADMA gradient (r=0.60; p=0.07). Decreased DDAH activity in the pre-eclamptic placenta might contribute to elevated ADMA levels in these patients.
    No preview · Article · Jan 2012 · European journal of obstetrics, gynecology, and reproductive biology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ziel dieses Konsensuspapiers ist es, die Anwendung des Kardiotokogramms (CTG) zur Überwachung des ungeborenen Kindes auf der Basis evidenzbasierter Methoden zu standardisieren. Dies erfolgt unter Berücksichtigung von Stör- und Einflussgrößen auf das CTG, unter Verwendung einheitlicher Definitionen und objektiver Bewertungsmöglichkeiten sowie durch Hinweise auf vorgeschaltete Diagnostik- und additive Überwachungsverfahren. Zielgruppe dieses Konsensuspapiers sind alle Berufsgruppen, die mit Hilfe einer CTG-Registrierung Schwangerschaft und Geburt überwachen, v. a. Frauenärzte und Hebammen. Methode: Die Erstellung dieser Leitlinie erfolgte unter besonderer Berücksichtigung der bisherigen Empfehlungen (85), der FIGO-Richtlinien (59, 82), der Richtlinien des Royal College of Obstetricians and Gynaecologists (84), der NICHD (72) und des American College of Obstetricians and Gynaecologists (4, 5) sowie – soweit vorliegend – evidenzbasierter Daten.
    Full-text · Article · Jan 2012 · Online
  • [Show abstract] [Hide abstract]
    ABSTRACT: Gastroschisis is a malformation consisting of an abdominal wall defect with eviscerated bowel. Its standard treatment is postnatal repositioning or temporary prosthetic bag placement. The aim of our study is to evaluate the feasibility of its fetoscopic management in a lamb model. At mid-gestation (day 75), gastroschisis was created in eight German blackhead sheep. A second fetoscopic procedure was performed on day 105, assessing the viability, extension, and potential for repositioning of eviscerated bowel. The fetus was retrieved by Cesarean section on day 132 and evaluated. In six fetuses gastroschisis could be successfully created and assessed with fetoscopy. Two fetuses were lost due to technical complications. Primary repair by repositioning the intestine into the abdomen was not possible because it grew into an inflammatory conglomerate too large for the small fetal abdominal cavity. Although technically demanding, we were able to produce and reassess six cases of gastroschisis by fetoscopy. As primary repositioning appears unfavorable, fetoscopic prosthetic bag placement may become an alternative.
    No preview · Article · Dec 2011 · Surgical Endoscopy
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE To perform cardiac MR imaging of the fetal heart in utero using a Doppler ultrasound probe of a standard cardiotocograph (CTG) as a triggering device and to compare the images with those from pulse-wave (PW) triggering. METHOD AND MATERIALS All magnetically perturbing components of the CTG's ultrasound transducer were replaced by non-magnetic materials. The CTG signal was protected against the electro-magnetic interference between the 65 MHz MR signal. MRI measurements were performed on 4 pregnant ewes carrying singleton fetuses. The fetuses were chronically instrumented with a carotid catheter to measure the fetal heart frequency for the PW triggering. The fetal heart rate (FetHR) was recorded by newly developed MR compatible ultrasound transducer of the CTG. Retrospective fetal cardiac PW and CTG gating was used on a 1.5 T MRI. GRAPPA retrogated Cine-MRI sequence was used in short axis, four and two chamber view. Skin exposure to local heat generation by eddy currents and RF energy absorption in the shielded ultrasound probe and its cable were tested by two adult subjects and was measured by using a MRI compatible thermometer. RESULTS After removing all perturbing components the artifacts of the probe itself were reduced. For both techniques, an adequate quantitative measurement was possible. Left-ventricular functions of the fetuses were measured form the short axis as well as from the four chamber views to assess the temporal left ventricular stroke volume and ejection fraction. The resulting ventricular filling rate patterns are very similar indicating that the CTG is registering the fetal heart beat with the same precision as the reference PW trigger. The thickness of the septum and the LV wall were 0.9 cm and 0.8 cm in diastole and 1.0 cm und 1.3 cm in systole, respectively, in both techniques and no differences could be measured. No local temperature increase was sensed during cardiac function assessment using the CTG and the PW- trigger. CONCLUSION The newly developed MR compatible cardiotocograph with its ultrasound transducer allowed a sufficient cardiac triggering of the fetal heart without artifacts. The so obtained cardiac MR images were comparable and as sufficient as pulse wave triggered MR images. CLINICAL RELEVANCE/APPLICATION Not only can the newly developed device used as triggering device for fetal cardiac MRI in utero, but also for monitoring the fetus during fetal MRI itself.
    No preview · Conference Paper · Nov 2011
  • G Ortmeyer · B Hollwitz · K Hecher

    No preview · Article · Nov 2011 · Zeitschrift für Geburtshilfe und Neonatologie
  • B Hollwitz · G Ortmeyer · K Hecher

    No preview · Article · Nov 2011 · Zeitschrift für Geburtshilfe und Neonatologie
  • G Ortmeyer · B Hollwitz · K Hecher

    No preview · Article · Nov 2011 · Zeitschrift für Geburtshilfe und Neonatologie
  • CJ Briffod · P Glosemeyer · K Hecher · B Hüneke

    No preview · Article · Nov 2011 · Zeitschrift für Geburtshilfe und Neonatologie
  • Source

    Preview · Article · Oct 2011 · Ultrasound in Obstetrics and Gynecology
  • Source

    Full-text · Article · Oct 2011 · Ultrasound in Obstetrics and Gynecology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Twin-twin transfusion syndrome (TTTS) is a severe complication occurring in about 10% of monochorionic twin pregnancies. The chronic unbalanced transfusion of blood across placental vascular communications from the donor to the recipient twin may lead to impairment of various organ systems in the affected twins. In Hamburg, Germany, since 1995 patients with TTTS were treated with fetoscopic laser coagulation as the first causal therapeutic strategy. All survivors after laser surgery were followed up in the University Children's Hospital in Bonn, Germany. In this article, we summarize long-term follow-up studies from our German study population and compare our results with data from the literature.
    No preview · Article · Jul 2011 · Prenatal Diagnosis

  • No preview · Article · Apr 2011 · RöFo - Fortschritte auf dem Gebiet der R
  • [Show abstract] [Hide abstract]
    ABSTRACT: Twin-to-twin transfusion syndrome (TTTS) is a severe complication of monochorionic (MC) twin pregnancies, characterized by the development of unbalanced chronic blood transfer from one twin, defined as donor twin, to the other, defined as recipient, through placental anastomoses. If left untreated, TTTS is associated with very high perinatal mortality and morbidity rates, due to a combination of fetal and/or obstetric complications. The reported prevalence is 10-15% of all MC twins, or about 1 in 2000 pregnancies. This consensus document reviews available evidence and offers practical guidance to clinicians by providing recommendations on various aspects concerning diagnosis and management of TTTS.
    No preview · Article · Mar 2011 · Journal of Perinatal Medicine

  • No preview · Article · Jan 2011

Publication Stats

6k Citations
1,081.48 Total Impact Points

Institutions

  • 2003-2015
    • University Medical Center Hamburg - Eppendorf
      • Department of Obstetrics and Fetal Medicine
      Hamburg, Hamburg, Germany
  • 2007-2011
    • University of Hamburg
      • Department of Obstetrics and Fetal Medicine
      Hamburg, Hamburg, Germany
  • 2007-2010
    • Universitair Ziekenhuis Leuven
      • Department of Gynaecology and obstetrics
      Louvain, Flanders, Belgium
  • 2008
    • William Beaumont Army Medical Center
      El Paso, Texas, United States
    • University of Groningen
      Groningen, Groningen, Netherlands
  • 2003-2007
    • University of Bonn - Medical Center
      Bonn, North Rhine-Westphalia, Germany
  • 2005
    • University of Münster
      • Department of Obstetrics and Gynaecology
      Münster, North Rhine-Westphalia, Germany
  • 2001
    • Utrecht University
      Utrecht, Utrecht, Netherlands
  • 1999
    • Universitair Ziekenhuis Ghent
      Gand, Flanders, Belgium
    • Academisch Medisch Centrum Universiteit van Amsterdam
      • Department of Obstetrics & Gynecology
      Amsterdamo, North Holland, Netherlands
  • 1995
    • Asklepios Klinik Barmbek
      Hamburg, Hamburg, Germany
  • 1994
    • King's College Hospital NHS Foundation Trust
      • Department of Obstetrics and Gynaecology
      Londinium, England, United Kingdom
    • King's College London
      • Division of Asthma, Allergy and Lung Biology
      Londinium, England, United Kingdom
  • 1992-1994
    • The Peninsula College of Medicine and Dentistry
      • School of Medicine
      Plymouth, England, United Kingdom