Comparison of the Snare Loop Technique and the Hungaroring Reinforcement for Physician-Modified Endograft Fenestrations-An In Vitro Study.

BACKGROUND: We conducted an in vitro comparison of the snare loop reinforcement against a closed-loop reinforcement (Hungaroring) for physician-modified endograft (PMEG) fenestrations regarding preparation time and stability during flaring balloon dilatation. MATERIALS AND METHODS: The time to complete a PMEG fenestration with reinforcement was measured and compared between the Hungaroring and snare loop groups. The number of stitches was counted. Each fenestration was dilated using a 10 mm high-pressure, non-compliant balloon up to 21 atm in pressure, and fluoroscopic images were taken. The presence of indentation on the oversized balloon at the level of the reinforcement was evaluated at each fenestration. RESULTS: Five fenestrations were created in each group (n = 5) for a total of ten pieces. The completion time in the snare loop group was 1070 s (IQR:1010-1090) compared to 760 s (IQR:685-784) in the Hungaroring group (p = 0.008). Faster completion time was achieved by faster stitching (23.2 s/stitch (IQR 22.8-27.3) for the snare loop group and 17.3 s/stitch (IQR 17.3-20.1) for the Hungaroring group (p = 0.016). None of the fluoroscopic images of the snare loop reinforcement showed an indentation on the balloon during the overexpansion; on the contrary, the Hungaroring showed indentation in every case, even at 21 atm. CONCLUSION: Fenestrations reinforced with Hungaroring can be completed significantly faster. Furthermore, the Hungaroring resists over-dilation even at high pressures, while snare loop reinforcements dilate at nominal pressure.

Older birds have better feathers: A longitudinal study on the long-distance migratory Sand Martin, Riparia riparia.

Feather quality is of critical importance to long-distance migratory birds. Here, we report a series of analyses of a unique data set encompassing known-age individuals of the long-distance migratory Sand Martin (Riparia riparia). Sampling over 17 years along the Tisza River, eastern Hungary, has resulted in the recapture of numerous individuals enabling longitudinal and cross-sectional investigation of the role of adaptation to variable environmental conditions on feather morphology. We show that older individuals tend to possess better quality feathers, measured using bending stiffness, feather length and thickness as proxies. Bending stiffness and feather thickness do not change with individual age, in contrast with increases in feather length and declines in daily feather growth versus age of individual alongside moult duration. Individuals who live to older ages tend to have similar, or higher, feather growth rates and better feather quality than individuals captured at younger ages. Thus, on the basis of strong selection against individuals with slow feather growth, as seen in other species of swallows and martins, which causes a delay in moult completion, the results of this analysis highlight the potential cost of producing better quality feathers when this depends on moult duration. Feather length also does change during the lifetime of the individual and thus enabled us to further investigate influence of individual and environmental conditions during the moult. The results of this analysis provide important insights on the adaptive significance of these traits, and the potential use of physical characteristics in unravelling the reasons why long distance migratory bird populations are in global decline.

Ablation time efficiency and lesion volume - in vitro comparison of 4 mm, non irrigated, gold- and platinum-iridium-tip radiofrequency ablation catheters.

PURPOSE: We investigated the development of in vitro lesion formation in relation to ablation time and power delivery using 4-mm, non-irrigated, platinum-iridium (Pt/Ir), and gold-tip catheters. METHODS: Radiofrequency catheter ablation was performed on porcine liver preparations in a 5-60-s time range with 5 s increments applied at different lesion sites. Each series was repeated four times for both catheters. The lesion volume, the delivered energy, and the ablation power curves were analyzed in 96 ablations. RESULTS: The delivered energy was higher and the lesion volume was significantly larger when using a gold-tip catheter. The lesion volume that was created with the Pt/Ir-tip electrode within 60 s was created after a shorter 40 s ablation period with the gold-tip electrode (Au, 40 s, 345 ± 75 mm(3) vs. Pt/Ir, 60 s, 328 ± 30 mm(3)). CONCLUSION: The gold-tip catheters had a lower tip temperature resulting in higher energy delivery due to the better thermo-conductivity of the gold alloy. A significantly higher lesion volume and a faster lesion creation were found for gold catheters as compared to Pt/Ir catheters. Gold-tip catheters can create the same adequate lesion within 33.3 % less ablation time due to the higher values of delivered energy as compared to those observed with the use of Pt/Ir catheters.

Methods for examination an explanted coronary sinus lead stabilized with a coronary stent.

The aim of our investigation was to test the suitability of a novel method for the analysis of the integrity of an explanted pacemaker lead stabilized by a stent. A coronary sinus lead has been explanted 27 months after implantation and has been examined by optical-, confocal-, x-ray-, and scanning electron microscopy. Several surface injuries were found on the insulation. Based on the surface characteristics, it is possible to define and differentiate the source of damages as well as to measure the extent of injuries. Impedance of the explanted lead has also been measured and electronic integrity has been verified.

Flexibility and trackability of laser cut coronary stent systems.

Coronary stents are the most important supports in present day cardiology. Flexibility and trackability are two basic features of stents. In this paper, four different balloon-expandable coronary stent systems were investigated mechanically in order to compare their suitability. The coronary stent systems were assessed by measurements of stent flexibility as well as by comparison of forces during simulated stenting in a self-investigated coronary vessel model. The stents were cut by laser from a single tube of 316L stainless steel or L-605 (CoCr) cobalt chromium alloy. The one-and four-point bending tests were carried out to evaluate the stent flexibility E x I (Nmm(2)), under displacement control in crimped and expanded configurations. The flexibility of stents would be rather dependent on the design than on raw material. In general a more flexible stent needs lower tracking force during the implantation. The L-605 raw material stents need lower track force to pass through in the vessel model than the 316L raw material stents. The sort and long stents passed through the curved vessel model in different ways. The long stents nestled to the vessel wall at the outer arc and bent, while the short stents did not bend in the curve, only the delivery systems bent.