Acquired von Willebrand syndrome in congenital heart disease surgery: results from an observational case-series.

Essentials Bleeding complications during congenital heart disease surgery in neonatal age are very common. We report the perioperative incidence of acquired von Willebrand syndrome (aVWS) in 12 infants. aVWS was detected in 8 out of 12 neonates and infants intraoperatively after cardiopulmonary bypass. Ten patients received von Willebrand factor concentrate intraoperatively and tolerated it well. SUMMARY: Background Cardiac surgery of the newborn and infant with complex congenital heart disease (CHD) is associated with a high rate of intraoperative bleeding complications. CHD-related anatomic features such as valve stenoses or patent arterial ducts can lead to enhanced shear stress in the blood stream and thus cause acquired von Willebrand syndrome (aVWS). Objective To evaluate the intraoperative incidence and impact of aVWS after cardiopulmonary bypass (CPB) in neonates and infants with complex CHD. Patients/Methods We conducted a survey of patients aged < 12 months undergoing complex cardiac surgery in our tertiary referral center. Twelve patients, whose blood samples were analyzed for aVWS before CPB and immediately after discontinuation of CPB on a routine basis, were eligible for the analysis. von Willebrand factor antigen (VWF:Ag), ristocetin cofactor activity (VWF:RCo), collagen binding activity (VWF:CB), VWF:multimers and factor VIII activity (FVIII:C) were determined. Results aVWS was diagnosed by VWF multimer analysis in 10 out of 12 patients (83%) prior to surgery and intraoperatively at the end of CPB in 8 out of 12 patients (66%). Ten patients received VWF/FVIII concentrate intraoperatively as individual treatment attempts during uncontrolled bleeding. They tolerated it well without intraoperative thrombotic events. One patient suffered a transient postoperative cerebral sinuous vein thrombosis. Conclusions aVWS is of underestimated incidence in complex CHD surgery. These data may offer a new approach to reduce the risk of severe bleedings and to achieve hemostasis during high-risk pediatric cardiac surgery by tailoring the substitution with von Willebrand factor concentrate.

[Morphofunctional evaluation of different parts of the cerebral cortex after ionizing radiation exposure].

The investigation has the aim to compare reactions of phylogenetically different parts of the brain cortex to single and fractionated irradiation by 1 Gy. The focus is primarily laid on unveiling the morphological stage of radiation-induced changes in the cortex. A hundred of 100 nubilous male rats with the body mass of 200-230 g were subject to whole-body uniform single and fractionated gamma-irradiation (total dose absorption over 5 days) with MeV spectrum 1.2 at 1 Gy (dose rate--50 cGy/h). Sampling of cortex motoria secundaria, cortex prelimbicus, hippocampus fields CA1-CA4, dentate fascia and cortex piriformis was conducted in a day, 6, 12 and 18 months after exposure. Brain sections were fixated in 10% formalin solution and then embedded in paraffin. Paraffin sections were stained by Karachi hematoxylin-eosin for review and Nissl methylene blue for cytoarchitectonics studies. In samples of every animal, 300 neurocytes were counted with careful examination of distinct changes in cell form, uniformity of cytoplasm staining, level of nucleus and nucleolus differentiation and Nissl substance basophilia. Late reparation of damaged neurocytes was observed after fractionated irradiation. Evidence of changes and time of compensation of damaged neurocytes correlate with method of irradiation, length of post-irradiation period and phylogenetic age of the cortex.

[Effects of small ionizing radiation doses on hemato-encephalic barrier permeability].

Goal and objectives of the study was comparative description and establishment of dose-time dependence of changes in permeability of the hemato-encephalic barrier (HEB) in phylogenetically different parts of the brain cortex, i.e. new (Fr2 and Cg3), old (hippocampal fields CA1-CA4 and dentate fascia) and paleocortex (piriform cortex) following exposure to 0.1; 0.2; 0.5 and 1 Gy of ionizing radiation (dose rate = 50 cGy). Dependence of microvessels permeability on dose, post-exposure time and cortex phylogenetic age was established. Changes in brain microvessels, in the phylogenetically young cortex in particular, produced by 0.5 Gy and 1 Gy remained uncompensated till the end of investigation. Pronounced changes persisted over the period of one year after radiation exposure; complete recovery was not observed even in the phylogenetically old cortex.