Jan Burkert

Kirschner wire migration from the right sternoclavicular joint to the heart: a case report.

Presented here is a rare case in which Kirschner wires migrated from the right sternoclavicular joint to the heart. A 29-year-old man suffering from sternoclavicular instability due to a motorcycle accident received surgical fixation with Kirschner wires. Six months after the surgery, the chest x-ray showed migration of the 3 broken wires to the anterior mediastinum and to the right hemithorax. The patient was asymptomatic and was scheduled for elective surgical extraction of the migrating wires because of the potential danger of injuring the mediastinal organs.During the surgery, the intracardiac location of all wires was discovered,and the wires were successfully extracted from the extracorporeal circulation. This rare and potentially lethal complication is discussed.

Effect of donor/recipient body weight ratio, donor weight, recipient weight and donor age on kidney graft function in children

BACKGROUND We hypothesized that supplementing a higher mass of renal parenchyma from adult donors, and their younger age, would improve graft function in paediatric recipients. METHODS We calculated estimated glomerular filtration rate (eGFR; Schwartz formula) and absolute glomerular filtration rate (absGFR) in 57 renal-grafted children (1995-2007) aged 3.1-17.9 years, weighing 12.9-85.0 kg, on discharge from the hospital after transplantation (TPL), 1 year after TPL and at the last follow-up (1.5-11.7 years after TPL). We correlated their eGFR with the individual ratio between the donor and the recipient body weight at the time of TPL (donor/recipient body weight ratio; D/R BWR), and we evaluated the effect of the donor and the actual recipient body weight on the eGFR and absGFR. RESULTS The D/R BWR varied from 0.65 to 5.23. We found a significant positive correlation between D/R BWR and eGFR at discharge from the hospital (P < 0.001), 1-year post-TPL (P < 0.001) and at the last follow-up (P < 0.05). Using multiple linear regression analyses, we found that both eGFR and absGFR values were much more determined by the actual recipient weight than by the donor weight (27/6% and 43/4% at discharge, by 24/4% and 57/0% 1 year after TPL, and 0/0% and 20/0% at the end of the follow-up). A tendency for lower eGFR with increasing age of donors was apparent at discharge and 1 year after TPL, but it reached statistical significance only at the last follow-up (r = 0.4254, P < 0.01). CONCLUSION In paediatric renal transplants, the value of D/R BWR directly correlated with eGFR in the early and late posttransplant periods. However, this correlation was mainly influenced by the recipient weight, while the donor weight played only a minor or negligible role.

Extension of Pulmonary Adenocarcinoma into the Left Atrium

A 62-year-old man presented with pulmonary adenocarcinoma that penetrated through the pulmonary vein into the left atrium. The tumor in the left atrium was removed via a right lower lobectomy under cardiopulmonary bypass. In selected cases, radical removal of a tumor in patients without mediastinal lymph node involvement may improve the prognosis. The use of cardiopulmonary bypass extends the possibilities of radical tumor removal.

The composition and biomechanical properties of human cryopreserved aortas, pulmonary trunks, and aortic and pulmonary cusps

Human cryopreserved allografts of pulmonary and aortic heart valves, aortas and pulmonary trunks are used for valve replacement. However, it is unknown how the composition of these allografts relate to their mechanical properties. Our aims were to correlate the histological compositions and passive mechanical properties of aortic and pulmonary valves and to observe the microcracks of aortas and pulmonary trunks. The following parameters were quantified: ultimate stress; ultimate strain; Youngs modulus of elasticity; valve cusp wall thickness; pulmonary and aortic intima-media thickness; area fraction of elastin, collagen and calcification; and length density of elastic fibres. The propagation of experimentally induced microcracks avoided elastic fibres. Ultimate strain was negatively correlated with the area fraction of calcification (r=-0.4) in aortas. Ultimate stress (r=0.27) and Youngs modulus in small deformation (r=0.29) and in large deformation (r=0.32) correlated with wall thickness in valve cusps. Youngs modulus (r=0.34) and ultimate strain (r=0.31) correlated with intima-media thickness. Ultimate strain correlated with the area fraction of elastin (r=-0.40) and collagen in the arteries (r=0.31). As conventional histology does not fully explain the mechanical properties of cryopreserved grafts, both morphological and biomechanical tests should be used complementarily when characterizing the ageing of the grafts.

Histological Composition and Mechanical Properties of Cryopreserved Samples of Aortic and Pulmonary Valves

Human cryopreserved allografts of pulmonary and aortic valves are routinely used as total valve replacement. For successful surgery it is needed to sufficiently preserve biomechanical properties and histological structures of allografts. However, it is not known how the mechanical properties of these allografts relate to their histological composition. The aim of our study was to compare the histological composition and mechanical properties of the valves. From allografts we prepared 2 valve cusps and samples of aorta or pulmonary trunk. In a previous study we had measured following parameters: ultimate stress, ultimate strain, Young’s moduli of elasticity, intima-media thickness, wall thickness, area fraction of elastin and area fraction of collagen in the whole wall. We found weak positive correlation between ultimate stress and Young’s modulus in small and large deformation with wall thickness in the valve cusps. In the arteries we found positive correlation between Young’s modulus in large deformation with intima-media thickness and ultimate strain with intima-media thickness and area fraction of collagen, and negative correlation between ultimate strain with area fraction of elastin. In our study we quantified also the other components of wall with mechanical significance, such as the fraction of smooth muscle cells and chondroitin sulfate, which belong to glycosaminoglycans. We did not find correlation between these components and mechanical properties of these valves. Therefore, it is recommended to perform both mechanical and histological analysis to further characterize cryopreserved allografts.

Allograft Heart Valve in Aortic Valve Surgery

After 60 years of experimental and clinical development of heart valve prostheses, ideal heart valve prosthesis is not available. The chapter tries to review the history as well as the contemporary role of an aortic allograft in aortic valve surgery. It provides the basic information concerning the allograft heart valves procurement, processing, cryopreservation and thawing in general. Current view of surgical techniques of aortic allograft transplantation as well as the indication of that particular aortic valve substitute are summarised, documenting that in many cardiac surgical departments it is still considered as a method of choice for aortic valve, annulus and root infective endocarditis treatment.

Structural changes arising from different thawing protocols on cryopreserved human allograft’s aortic valve leaflets

BACKGROUND The aim of our experimental work was to assess the impact and morphological changes that arise during different thawing protocols on human aortic valve (AV) leaflets resected from cryopreserved aortic root allografts (CARAs). OBJECTIVES Two thawing protocols were tested: 1. CARAs were thawed at a room temperature (23°C); 2. CARAs were placed directly into a water bath at a temperature of 37°C. After all the samples were thawed, non-coronary AV leaflets were sampled from each specimen and fixed in a 4% formaldehyde solution before they were sent for morphological analysis. MATERIAL AND METHODS All the samples were washed in distilled water for 5 min and dehydrated in a graded ethanol series (70%, 85%, 95%, and 100%) for 5 min at each level. The tissue samples were then immersed in 100% hexamethyldisilazane (HMDS) for 10 min, and then air-dried in an exhaust hood at room temperature. Processed samples were mounted on stainless steel stubs and coated with gold. Histological analysis was performed with the use of an electron microscope on a scanning mode operating at 25 kV - BS 301. RESULTS Thawing protocol 1 (room temperature at 23°C): 6 (100%) samples showed loss of the endothelial covering of the basal membrane with no damage to the basal lamina. Thawing protocol 2 (water bath at 37°C): 5 (83%) samples showed loss of the endothelial covering of the basal membrane with no damage to the basal lamina. One (17%) sample showed loss of the endothelial covering the basal membrane with significant damage to the basal membrane. CONCLUSIONS Based on our experimental work, we can clearly conclude that cryopreserved AV leaflet allografts show identical structural changes at different rates of thawing.

Cryopreserved human aortic root allografts arterial wall: Structural changes occurring during thawing

Background The aim of our experimental work was to assess morphological changes of arterial wall that arise during different thawing protocols of a cryopreserved human aortic root allograft (CHARA) arterial wall. Methods The experiment was performed on CHARAs. Two thawing protocols were tested: 1, CHARAs were thawed at a room temperature at +23°C; 2, CHARAs were placed directly into a water bath at +37°C. Microscopic samples preparation After fixation, all samples were washed in distilled water for 5 min, and dehydrated in a graded ethanol series (70, 85, 95, and 100%) for 5 min at each level. The tissue samples were then immersed in 100% hexamethyldisilazane for 10 minutes and air dried in an exhaust hood at room temperature. Processed samples were mounted on stainless steel stubs, coated with gold. Results Thawing protocol 1: All 6 (100%) samples showed loss of the endothelium and damage to the subendothelial layers with randomly dispersed circular defects and micro-fractures without smooth muscle cells contractions in the tunica media. Thawing protocol 2: All 6 (100%) samples showed loss of endothelium from the luminal surface, longitudinal corrugations in the direction of blood flow caused by smooth muscle cells contractions in the tunica media with frequent fractures in the subendothelial layer Conclusion All the samples thawed at the room temperature showed smaller structural damage to the CHARA arterial wall with no smooth muscle cell contraction in tunica media when compared to the samples thawed in a water bath.

Moderately Decreased Dietary Salt Intake Suppresses the Progression of Renal Insufficiency in Rats with 5/6 Nephrectomy

Aim. Up to now, an appropriate salt intake in renal insufficiency has not been clearly determined. We hypothesize that even a moderate decrease in salt intake may affect functional and morphologic response of the rat remnant kidney after 5/6 nephrectomy. Methods. Subtotal nephrectomy was performed in 77 inbred 12 week-old-female AVN Wistar rats. The two groups of rats were fed either a standard or a low salt diet. Median of salt intake was 14.6 and 10.4 mg/100 g/24 h in the two groups. Results. Ten weeks after ablation, the remnant kidney parenchyma wet weight was 0.66 ± 0.16 g/100 g of body weight and 0.56 ± 0.11 g/100 g of body weight () in rats with a standard and low salt diet, respectively. In these two groups, systolic blood pressure was 151 ± 29 versus 126 ± 21 mmHg (), serum creatinine levels were 164 ± 84 versus 106 ± 29 µmol/L (), proteinuria was 84 ± 37 versus 83 ± 40 mg/100 g/24 h (N.S.), and the glomerular injury score was 2.06 ± 0.49 versus 1.43 ± 0.62 (), respectively. Conclusion. Moderately decreased salt intake slowed down the development of ablation nephropathy in AVN inbred strain of rats.