Recanalization of occluded coronary arteries is the aim of percutaneous interventions with acute myocardial infarction. Moreover, chronic coronary occlusion is a common finding during diagnostic ...coronary angiography and is often a contributing factor in the choice of revascularisation by surgery rather than by percutaneous coronary interventions (PCI). An occluded coronary artery with some degree of collateral supply is functionally comparable to a severe coronary stenosis. Therefore, recanalization of chronic occluded coronary arteries results in less angina and often in improvement of left ventricular function. Success is limited in particular in longer lasting occlusions. Characterization of lesions, where recanalization can performed successfully is warranted. We correlated primary success rates of attempted coronary recanalizations with localisation of lesions and procedural characteristics. We analyzed records of 124 consecutive patients, who underwent attempted coronary recanalization of chronically occluded coronary arteries at our institution in 1998. Revascularisation was successful in 84 (64 male, 20 female) of 124 (92 male, 32 female) patients. Therefore, success rate was 67.7% (69.9% in men, 62.5% in women, p = 0.42). Target vessel was the left anterior descending artery (LAD) in 49 cases. Success rate in the LAD did not differ significantly from that in "non-LAD"-vessels (65.3% versus 69.3%; p = 0.35). Successful recanalizations were performed using only one guide-wire in 77.3%. More than one guide-wires were used during procedures without success in 44.5% and exceeded use in successful interventions (p < 0.05). Procedures, failing to be successful after an attempt with a first guide-wire, could be performed successfully using at least a second wire in 50%. Coronary stenting after recanalization has been performed in 84.4% in the LAD and in 59.7% in non-LAD vessels (p < 0.01). Success rate of attempted recanalizations of chronic occluded coronary arteries in unselected patients is high. Most procedures can be performed successfully using only one guidewire. Additional use of other wires can increase success rates in procedures with primary failure to pass the occlusion. Stenting has been performed in three out of four patients with successful recanalization of chronically occluded coronary arteries.
Static shear tests are the state of the art testing methods for assessment of reliability and bonding strength of thermosonic ball bonds in microelectronic devices. As such interconnects are ...subjected to elevated temperatures and thermo-mechanically induced cyclic stresses, a degradation at the interface is expected that affects the reliability of ball bonded interconnects leading to subsequent fatigue failure. In this study a new accelerated mechanical fatigue testing method is proposed for determination of lifetime of miniaturized Cu-Al ball bonded interconnects. Lifetime is determined by subjecting interconnects to cyclic shear stresses at preset shear stress amplitudes. The effect of microstructural evolution to high temperature storage on bonding strength and lifetime of Cu-Al ball bonds was evaluated by means of static shear tests and the new fatigue testing method. The response of thermosonic ball bonds to static and cyclic loading was compared and discussed considering the fracture surface analysis of interconnects in as-bonded and aged conditions.
Zusammenfassung: Die Eröffnung verschlossener Koronararterien wird einerseits im Rahmen der Akutangioplastie beim akuten Myokardinfarkt angestrebt, andererseits werden Rekanalisationen chronischer ...Koronarverschlüsse mit der Zielsetzung einer Verbesserung der Angina‐pectoris‐Symptomatik oder einer Funktionsverbesserung der linksventrikulären Pumpfunktion durchgeführt. Gerade bei länger bestehenden Verschlüssen ist die Erfolgsrate der Rekanalisation limitiert. Eine Charakterisierung von chronischen Koronarokklusionen, die mit Erfolg rekanalisiert werden können, ist daher von Interesse. Ziel der Untersuchung war eine Analyse der Erfolgsraten von versuchten Koronarrekanalisationen in Abhängigkeit von der Lokalisation des Verschlusses und von verschiedenen technischen Variablen. Es wurden die Krankengeschichten von 124 konsekutiven Patienten anhand einer retrospektiven Analyse analysiert, die im Zeitraum vom 1. 1. 1998 bis zum 31. 12. 1998 einem Rekanalisationsversuch einer verschlossenen nativen Koronararterie unterzogen wurden. Bei den 124 Patienten (92 Männer, 32 Frauen) war die Rekanalisation in 84 Fällen (64 Männer, 20 Frauen) erfolgreich, die Erfolgsrate betrug somit 67,7 % (Männer – 69,6 %, Frauen – 62,5 %; p = 0,42). Der Ramus interventrilularis anterior (RIVA; LAD) war in 49 Fällen das Zielgefäß, wobei die Erfolgsrate bei 65,3 % lag. Die Erfolgsrate von 69,3 % bei den „Nicht‐LAD‐Gefäßen” war nicht signifikant unterschiedlich (p = 0,35). Bei den erfolgreichen Interventionen konnte mit der Verwendung von einem Drahtsystem in 77,3 % das Auslangen gefunden werden, bei den letztlich erfolglosen Rekanalisationsversuchen wurde mit 47,5 % signifikant häufiger zumindest ein weiteres Drahtsystem zur Anwendung gebracht (p < 0,05). Die Verwendung eines oder mehrerer weiterer Drahtsysteme war in 50 % bei primär erfolglosem Passageversuch des Verschlusses schließlich doch mit einer erfolgreichen Rekanalisation assoziiert. Die Implantation eines Koronarstents erfolgte in 77,4 % der Rekanalisationen, wobei eine rekanalisierte LAD in 84,4 % mit einem Koronarstent versorgt wurde. Bei den „Nicht‐LAD‐Gefäßen” betrug die Stentrate 59,7 %. In etwa zwei Drittel der Fälle ist die versuchte Rekanalisation erfolgreich durchführbar. In der überwiegenden Anzahl der Fälle gelingt die Passage des Verschlusses unter Verwendung von nur einem Drahtsystem, im Falle eines ersten erfolglosen Versuches ist durch die Verwendung von zumindest einem weiteren Drahtsystem in der Hälfte der Fälle eine erfolgreiche Intervention möglich. Drei von vier Patienten mit erfolgreicher Rekanalisation eines Koronararterienverschlusses wurden mit einem Koronarstent versorgt.
Recanalization of Chronic Coronary Occlusions
Summary: Recanalization of occluded coronary arteries is the aim of percutanous interventions with acute myocardial infarction. Moreover, chronic coronary occlusion is a common finding during diagnostic coronary angiography and is often a contributing factor in the choice of revascularisation by surgery rather than by percutanous coronary interventions (PCI). An occluded coronary artery with some degree of collateral supply is functionally comparable to a severe coronary stenosis. Therefore, recanalization of chronic occluded coronary arteries results in less angina and often in improvement of left ventricular function. Success is limited in particular in longer lasting occlusions. Characterization of lesions, where recanalization can performed successfully is warranted. We correlated primary success rates of attempted coronary recanalizations with localisation of lesions and procedural characteristics. We analyzed records of 124 consecutive patients, who underwent attempted coronary recanalization of chronically occluded coronary arteries at our institution in 1998. Revascularisation was successful in 84 (64 male, 20 female) of 124 (92 male, 32 female) patients. Therefore, success rate was 67,7 % (69,9 % in men, 62,5 % in women, p = 0,42). Target vessel was the left anterior descending artery (LAD) in 49 cases. Success rate in the LAD did not differ significantly from that in „non‐LAD”‐vessels (65,3 % versus 69,3 %; p = 0,35). Successful recanalizations were performed using only one guide‐wire in 77,3 %. More than one guide‐wires were used during procedures without success in 44,5 % and exceeded use in successful interventions (p < 0,05). Procedures, failing to be successful after an attempt with a first guide‐wire, could be performed successfully using at least a second wire in 50 %. Coronary stenting after recanalization has been performed in 84,4 % in the LAD and in 59,7 % in non‐LAD vessels (p < 0,01). Success rate of attempted recanalizations of chronic occluded coronary arteries in unselected patients is high. Most procedures can be performed successfully using only one guide‐wire. Additional use of other wires can increase success rates in procedures with primary failure to pass the occlusion. Stenting has been performed in three out of four patients with successful recanalization of chronically occluded coronary arteries.
A novel accelerated mechanical fatigue testing system in combination with a special set-up was used to evaluate the reliability of Cu-ball bonds. Tailor made test structures were designed and ...prepared out of commercial wire bonded devices to assess bonding strength of the interconnects under various modes of cyclic loading. Fracture surface analysis of the interconnects showed wire bond lift-off as the dominant failure mode. Based on experimental results and FEM simulations, lifetime prediction curves for two different types of ball bonded devices could be established.
Partial reverse transcriptase sequencing of 16S rRNA from Mobiluncus curtisii and M. mulieris clearly indicate that the genus Mobiluncus is not a member of the Bacteroidaceae but belongs to the order ...Actinomycetales. The highest degree of relationship is found with the genus Actinomyces which is supported by the presence of common physiological properties.
We studied the influence of a moderate homeopathically prepared thyroxine dilution (final concentration in the basin water 10-(13) parts by weight) on the metamorphosis of lowland Rana temporaria ...which had been hyperstimulated with thyroxine. Two groups of animals were pretreated by immersing them in a molecular thyroxine dilution (10-(8) parts by weight). This pretreatment speeds up development, as is well known. In accordance with the homeopathic/isopathic idea of detoxication or cure, the same hormone was then diluted and agitated in successive steps for further treatment. This homeopathically prepared dilution was administered at 24-hour intervals to one of the groups. An analogously prepared blank solution was used for the control group. Our hypothesis, which was derived from earlier studies, was that animals treated with the test solution would metamorphose more slowly than the control animals, i.e. that the homeopathically prepared thyroxine would have a 'curative' effect. In this new series of experiments this hypothesis was examined by 3 independent researchers. In the experiments carried out by 2 of the 3 researchers the number of animals that reached the four-legged stage at defined points in time was smaller in the group treated with homeopathically prepared thyroxine. In the third laboratory no difference was found between the groups. However, the overall inhibiting effect was statistically significant and more pronounced than in earlier, less promising studies and in parallel experiments in which nonprestimulated animals had been used. Other studies carried out by the 3 researchers involved animals from highland biotopes, where the natural environment probably induces a greater sensitivity towards thyroxine or higher thyroxine levels. These animals reacted to the homeopathically prepared thyroxine with a slowing down of metamorphosis, even when they had not been prestimulated with a molecular dose of the hormone. This effect was observed in all 3 laboratories and is consistent with the results of previous studies.
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