A contribution to the characterization of the silicate-water interface - Part II: Atom Probe Tomography of tricalcium silicate.

This work explores the possibility to investigate the nanoscale cement-water interface by means of atom-probe tomography (APT). For this purpose, the main compound of Ordinary Portland Cement, tricalcium silicate, and its hydration product calcium-silicate-hydrate have been analyzed by APT. Of special interest was the surface of anhydrous and hydrated tricalcium silicate. The results show, that a nanoscale characterization of tricalcium silicate with APT is possible by carefully controlling the various measurement parameters. Furthermore, our results indicate, that the conditions during focused ion beam sample preparation, especially the high vacuum and energy input, are potentially harmful to calcium-silicate-hydrate. Future developments in cryo sample preparation will greatly enhance the applicability of APT on cement and its hydration products.

A contribution to the characterization of the silicate-water interface - Part I: Implication of a new polished sample hydration technique.

The analysis of the atomic composition of the interface between tricalcium silicate (C3S), the main compound of Ordinary Portland Cement, and surrounding solution is still a challenging task. At the same time, that knowledge is of profound importance for describing the basic processes during hydration. By means of Scanning Electron Microscopy (SEM) and Atom Probe Tomography (APT) we combine modern techniques in order to shed light on this topic in the present study. The results of these methods are compared with conduction calorimetry as a standard technique to study the hydration kinetics of cement. The tests were carried out on powders as well as on polished C3S samples. Results indicate that the progress of hydration is strongly increased when the C3S is used in the form of polished specimen. First C-S-H phases are detected in the powder 2.2 h after contact with water, on the polished section after 5 min. Besides SEM, the formation of C-S-H phases can be detected by APT, leading to an advantageous atomic resolution compared to EDX analysis. We propose that the use of APT will lead to deeper insights on the hydration progress and on the composition of the sensitive C-S-H phases based on these first results.

Randomized Trial of Primary PCI with or without RoutineManual Thrombectomy

During primary percutaneous coronary intervention (PCI), manual thrombectomymay reduce distal embolization and thus improve microvascular perfusion. Smalltrials have suggested that thrombectomy improves surrogate and clinical outcomes,but a larger trial has reported conflicting results.MethodsWe randomly assigned 10,732 patients with ST-segment elevation myocardial infarction(STEMI) undergoing primary PCI to a strategy of routine upfront manualthrombectomy versus PCI alone. The primary outcome was a composite of deathfrom cardiovascular causes, recurrent myocardial infarction, cardiogenic shock, orNew York Heart Association (NYHA) class IV heart failure within 180 days. The keysafety outcome was stroke within 30 days.ResultsThe primary outcome occurred in 347 of 5033 patients (6.9%) in the thrombectomygroup versus 351 of 5030 patients (7.0%) in the PCI-alone group (hazard ratio in thethrombectomy group, 0.99; 95% confidence interval [CI], 0.85 to 1.15; P = 0.86). Therates of cardiovascular death (3.1% with thrombectomy vs. 3.5% with PCI alone;hazard ratio, 0.90; 95% CI, 0.73 to 1.12; P = 0.34) and the primary outcome plusstent thrombosis or target-vessel revascularization (9.9% vs. 9.8%; hazard ratio,1.00; 95% CI, 0.89 to 1.14; P = 0.95) were also similar. Stroke within 30 days occurredin 33 patients (0.7%) in the thrombectomy group versus 16 patients (0.3%)in the PCI-alone group (hazard ratio, 2.06; 95% CI, 1.13 to 3.75; P = 0.02).ConclusionsIn patients with STEMI who were undergoing primary PCI, routine manual thrombectomy,as compared with PCI alone, did not reduce the risk of cardiovasculardeath, recurrent myocardial infarction, cardiogenic shock, or NYHA class IV heartfailure within 180 days but was associated with an increased rate of stroke within30 days. (Funded by Medtronic and the Canadian Institutes of Health Research;TOTAL ClinicalTrials.gov number, NCT01149044.

Outcome of percutaneous coronary intervention with drug-eluting stents in unprotected left main versus non-left main native coronary artery disease: results from the prospective multicenter German DES.DE registry.

BACKGROUND: Unprotected left main coronary artery (ULMCA) disease is considered an indication for surgical revascularization. However, refined percutaneous coronary intervention (PCI) technology and modern drug-eluting stents (DES) render the ULMCA a target for interventional treatment. METHODS AND RESULTS: Between October 2005 and September 2009, 374 patients receiving DES in ULMCA and 18,678 patients receiving DES in non-left main coronary arteries (nLMCA) with no previous coronary artery bypass graft surgery, were registered at 130 DES.DE sites. The composite of death, myocardial infarction (MI), and stroke defined as major adverse cardiac and cerebrovascular events (MACCE) and target vessel revascularization (TVR) were defined as primary endpoints. Baseline clinical and descriptive morphology of coronary artery disease revealed more comorbidities and more complex anatomies in the ULMCA group. At 1-year follow-up, the ULMCA group suffered from higher rates of overall death (5.6 versus 2.3 %; p < 0.0001), stroke (2.0 versus 0.8 %; p < 0.05), MACCE (8.6 versus 4.9 %; p < 0.01); whereas rates for definite/probable stent thrombosis (2.4 versus 1.6 %; p = 0.29), TVR (14.2 versus 10.8 %; p = 0.06) and MI (1.3 versus 1.9 %; p = 0.44) were not statistically different. These results persisted even after adjustment for different baseline characteristics, except MACCE that was no longer statistically significant. CONCLUSION: Data collected in DES.DE revealed that ULMCA PCI with DES result in similar TVR rates as compared to PCI in nLMCA. Moreover, modern DES have not offset the higher comorbidity index and higher procedure-related complication rate with PCI of ULMCA lesions.

[Antibiotic prophylaxis in urology]. / Antibiotikaprophylaxe in der Urologie.

The aim of perioperative antibiotic prophylaxis is the prevention of surgical site infections and urinary tract infections during urological procedures. The indication for antibiotic prophylaxis comprises several risk factors such as the degree of contamination of the operative site, duration of surgery, implantation of devices and comorbidities of the individual patient. In general this involves a single antibiotic administration before the operative procedure. The antibiotic prophylaxis is part of the total antibiotic consumption and thus a factor contributing to emergence of antibiotic resistance. It is not a substitute for hygiene measures or operative precision.

Echocardiography versus intracardiac electrocardiography-based optimization for cardiac resynchronization therapy : a comparative clinical long-term trial.

BACKGROUND: Optimization of AV and VV delay programming has been shown to be essential for the success of cardiac resynchronization therapy (CRT). Acute hemodynamic improvement can be obtained by intracardiac electrocardiogram (IEGM)-based optimization. The aim of the present study was to evaluate whether this IEGM-based algorithm is comparable to the current gold standard of echocardiography. METHODS: After device implantation patients with standard criteria for CRT, AV and VV delay programming was either optimized by an IEGM-based algorithm (IEGM group, n = 24) or by echocardiography (echo group, n = 24). Cardiopulmonary exercise capacity was assessed after 3 and 12 months on the basis of NYHA class and the 6-min-walk test. Left ventricular ejection fraction was evaluated by echocardiography. RESULTS: In both groups there was a significant decrease in NYHA class and a significant increase in 6-min-walk distance and ejection fraction after 3 and 12 months. After 12 months there was no significant difference in the proportion of responders, NYHA class and 6-min-walk distance between the IEGM the echo group. CONCLUSION: The present data show that a sustained improvement of cardiopulmonary exercise capacity can be obtained by optimizing CRT patients on the basis of an IEGM algorithm. The comparable results for cardiopulmonary exercise parameters suggest that this new method might become an important tool for adjusting CRT programming in daily practice.

[Therapy and prophylaxis of infective endocarditis]. / Therapie und Prophylaxe der infektiösen Endokarditis.

Infective endocarditis is an infection of cardiovascular structures which is typically caused by bacteria. Despite recent medical advances mortality ranges from 20 to 25%. Without treatment, IE is a lethal disease. The mortality rate depends on several clinical factors including the causative microorganism, the time of diagnosis, and the initiation of an adequate therapeutic regimen. The diagnosis is based on positive blood culture results with identical microorganisms and the demonstration of endocardial involvement. Negative blood cultures represent a diagnostic challenge which may increase the importance of diagnostic tools such as serology and PCR. An early and targeted initiation of an antibiotic therapy after microbiologic testing is crucial for therapeutic success. The immediate cooperation of Cardiologists, Microbiologists, Infectious Disease Specialists and Cardiac Surgeons is highly recommended to allow an adequate medical and surgical treatment in complex cases.Prophylaxis appears reasonable due to the inherent high mortality. The efficacy of an antibiotic prophylaxis is, nevertheless, not rigorously proven. Even if a high efficacy is assumed, the number needed to treat is extremely high due to the low individual risk. Thus, current guidelines recommend an antibiotic prophylaxis only in patients with a high risk for an adverse outcome.

Future strategies for treating Staphylococcus aureus bloodstream infections.

Bloodstream infections are potentially life-threatening diseases. They can cause serious secondary infections, such as infective endocarditis and osteomyelitis, and may result in severe sepsis. One of the most critical determinants of survival is the induction of timely and effective antibiotic therapy. One of the leading causes of bloodstream infections is Staphylococcus aureus, with an increasing proportion of isolates being resistant to methicillin. Methicillin-resistant S. aureus (MRSA) is associated with greater morbidity and mortality rates than methicillin-sensitive S. aureus (MSSA). Standard-of-care antibiotic treatments for S. aureus bloodstream infections are limited by toxicity and/or differential efficacy against MRSA and MSSA, which makes the choice of empirical therapy difficult. New management strategies are required to address the challenges raised by S. aureus bloodstream infections and MRSA in particular. These may include the use of techniques that allow the early identification of complications arising from S. aureus bacteraemia, rapid pathogen identification to enable the administration of appropriate antibiotic therapy, and the identification of new drugs with novel modes of action that may circumvent antibiotic resistance and enable effective empirical treatment of both MSSA and MRSA infections.

[Methods to evaluate aspirin and clopidogrel resistance]. / Methoden zur Messung der Azetylsalizylsäure- bzw. Clopidogrelresistenz.

Based on the concept that the so-called resistance to anti-platelet drugs is meant to describe a phenomenon where the drug does not hit its direct pharmacodynamic target, assays, used to evaluated the effects of anti-platelet drugs, should as closely as possible measure the direct pharmacodynamic effect of a particular drug. Thus, for the detection of aspirin effects, thromboxane concentrations or arachidonic acid-induced responses (light aggregometry, whole-blood aggregometry) should be measured. For the detection of clopidogrel actions, VASP phosphorylation (flow cytometry) or ADP-induced responses (light aggregometry, whole blood aggregometry) should be analysed.

Post-interventional homocysteine levels: failure as a predictive biomarker of in-stent restenosis.

OBJECTIVES: Purpose of our study was to determine if homocysteine plasma levels are related to the risk of in-stent restenosis after percutaneous coronary stent implantation in de novo lesions. BACKGROUND: The putative role of homocysteine as a predictive cardiovascular biomarker of coronary artery disease is well established. The impact of homocysteine levels in the development of in-stent restenosis, however, is controversially discussed. METHODS: A total of 177 patients with stable angina pectoris undergoing stent implantation in coronary de novo lesions were included. Laboratory determination comprised blood sample evaluation for homocysteine and other conventional risk factors before baseline coronary intervention and prior to six months control catheterization. Binary restenosis, late lumen loss, and late loss index after six months were assessed by quantitative coronary angiography. Endpoints included target lesion and target vessel failure, homocysteine levels as well as major adverse cardiac events. RESULTS: There was a significant correlation between the length of the implanted stent (p<0.006), the percentage of stenosis (p<0.003) and the pre-interventional luminal diameter (p<0.0001) with late loss index. Linear regression analysis demonstrated no significant impact of the initial or six months homocysteine levels on angiographic restenosis, late lumen loss, or late loss index. CONCLUSIONS: In contrast to homocysteine levels, luminal diameter, stent length and percentage of stenosis correlated with the appearance of restenosis. Taking our data into consideration, we hypothesise that homocysteine may not serve as a safe and independent biomarker of in-stent restenosis after a six months period following percutaneous coronary stenting.

Resistant hypertension in patients with chronic aortic dissection.

Strict blood pressure control is pivotal in the management of patients with aortic dissection (AD), but is frequently difficult to achieve. We determined antihypertensive medical therapy and levels of blood pressure (BP) control in 40 patients with chronic AD. Patient charts were reviewed for clinical variables, serial BP measurements, and antihypertensive drug therapy. Patients were divided into two groups: patients in group 1 had effective BP control (<135/80 mmHg), patients in group 2 had resistant hypertension (BP>/=135/80 mmHg despite prescription of at least three antihypertensive drugs). Overall, systolic BP (SBP) was 130+/-20 mmHg, and diastolic BP (DBP) was 72+/-13 mmHg. Patients received a median of 4 (1-6) antihypertensive drugs. beta-blockers were used in 38/40 (95%) patients. Effective BP control was achieved in 24/40 (60%) patients (group 1), while 16/40 (40%) patients had resistant hypertension (group 2) despite receiving significantly more antihypertensive drugs (5 [4-6] vs 4 [1-5], P=0.001). Mean SBP was 116+/-9 (101-132) mmHg in group 1 and 151+/-13 (137-181) mmHg in group 2 (P<0.001); there was no difference in DBP. Group 2 patients had a significantly higher body mass index and were younger than patients in group 1. In conclusion, in the majority of patients with chronic AD, effective BP control can be achieved, but usually requires the combination of multiple antihypertensive drugs. However, in a significant proportion of patients (40%), who appear to be younger and more obese, medical therapy fails to achieve effective BP control despite use of a multiple drug regimen.

Acute and long-term outcome after coronary artery perforation during percutaneous coronary interventions.

BACKGROUND: Coronary artery perforation is a rare but serious complication of percutaneous coronary interventions (PCI). METHODS: We reviewed our database for cases of overt coronary perforation during PCI procedures. Hospital charts, procedural reports, and coronary angiograms of these patients were reviewed, with particular emphasis on mechanisms of perforation, management of the complication, and clinical outcome. RESULTS: Between 01/1998 and 12/2003, a total of 19 cases (mean age: 66+/-8 years, 13 male) of coronary perforation occurred during 6433 PCI procedures performed within this period (incidence: 0.3%). In 12/19 (63%) cases, perforation occurred during recanalisation procedures of chronic total occlusions of coronary arteries. In all but one patient, non-surgical management was attempted: 2 out of 19 (11%) patients were treated conservatively by reversal of heparin anticoagulation. Prolonged balloon inflation at the perforation site was applied in 10/19 (53%) patients. Six (32%) patients received stents (5 of them received covered stentgrafts), 3 (16%) patients developed cardiac tamponade requiring percardiocentesis, and only 2 (11%) patients underwent bailout surgical repair. There were 2 (11%) deaths early after the procedure. CONCLUSION: Coronary perforation during PCI is a rare complication, but is associated with significant morbidity and mortality. In the majority of patients, non-surgical management is both feasible and associated with a high success-rate.

Genetics of human arterial hypertension.

Arterial hypertension is one of the major cardiovascular risk factors in Western countries. Besides some well established, but rather rare forms of secondary hypertension, essential hypertension is the most common diagnosis. The hereditary nature of this disease has been well established in many familial studies. The quantitative contribution of genetic factors to blood pressure variance is estimated to be about 30%, however, the genetic background of essential hypertension is complex and currently not fully understood. Besides few monogenetic forms of Mendelian transmitted hypertension, current efforts are usually directed at the identification of single contributing genetic factors. This review is thought to highlight current strategies towards a better understanding of the genetic background of essential hypertension with particular respect to genetic variants of the renin-angiotensin system, of signaling pathways such as heterotrimeric G-proteins and alpha-adducin. Moreover, genetic association studies often fail to replicate findings from previous studies. This may be in part due to the polygenetic nature of the disease. Another potential reason may be the diversity of the investigated populations. The current results of genetic analyses of essential hypertension highlight, thus, the need for a more differentiated approach to the understanding of complex, polygenetic traits implementing gene-gene-, and gene-environment interactions or distinguished functional testing of thoroughly phenotyped cohorts under standardised environmental conditions.

Genetics of human coronary vasomotion.

While the number of genetic polymorphisms associated with cardiovascular diseases rapidly increases, the functional implications of such gene alterations are often poorly understood. Moreover, findings from genetic association studies are often contradictory, which limits the common acceptance of a role of these genetic variants in human disease. One effective approach towards a better understanding of the pathophysiologic relevance of a gene variant is the description of its impact on dynamic or functional phenotypes such as coronary vasomotor responses to exogenous or endogenous stimuli. This brief review focuses on the impact of variants in genes of the renin-angiotensin system, the alpha2-adrenoceptor gene, and the G protein beta3 subunit gene on coronary vasomotor responses.

[S2 guideline for infectious endocarditis]. / S2 Leitlinie zur Diagnostik und Therapie der infektiösen Endokarditis. Finale Version 5.0 08/2004.

Microbe-induced (infectious) endocarditis is an endovascular infection, caused mainly by bacteria, of cardiovascular structures. The major predilection site are the native heart valves, but involvement of implanted intracardiac foreign material is increasingly being seen. The mortality rate of infectious endocarditis depends on clinical factors and the causal agent, but also on the time of the establishment of the diagnosis and the initiation of appropriate treatment. In Germany, the current mortality rate ranges up to 18%. Between January 2003 and July 2004, with the aim of improving patient care and thus the outcome of this condition, a guideline commission worked out recommendations for the diagnosis, treatment and management of the disease for the use of general practitioners and hospital physicians, in particular microbiologists, infectiologists, cardiologists and cardiac surgeons. The basis for this guideline was the systematic search through the literature of the European guideline. On the 16th and 28th of June 2004, the entire guideline was formerly approved in a nominal group process.

Plasma gonadotropins and ovarian hormones during the estrous cycle in high compared to low ovulation rate gilts.

Mature gilts classified by low (12 to 16 corpora lutea [CL], n = 6) or high (17 to 26 CL, n = 5) ovulation rate (OR) were compared for plasma follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone, estradiol-17beta, and inhibin during an estrous cycle. Gilts were checked for estrus at 8-h intervals beginning on d 18. Blood samples were collected at 8-h intervals beginning on d 18 of the third estrous cycle and continued for one complete estrous cycle. Analysis for FSH and LH was performed on samples collected at 8-h intervals and for ovarian hormones on samples collected at 24-h intervals. The data were standardized to the peak of LH at fourth (d 0) and fifth estrus for the follicular phase and analyzed in discrete periods during the periovulatory (-1, 0, +1 d relative to LH peak), early-luteal (d 1 to 5), mid-luteal (d 6 to 10), late-luteal (11 to 15), periluteolytic (-1, 0, +1 d relative to progesterone decline), and follicular (5 d prior to fifth estrus) phases of the estrous cycle. The number of CL during the sampling estrous cycle was greater (P < 0.005) for the high vs low OR gilts (18.8 vs 14.3) and again (P < 0.001) in the cycle subsequent to hormone measurement (20.9 vs 14.7). For high-OR gilts, FSH was greater during the ovulatory period (P = 0.002), the mid- (P < 0.05) and late-luteal phases (P = 0.01), and tended to be elevated during the early-luteal (P = 0.06), but not the luteolytic or follicular periods. LH was greater in high-OR gilts during the ovulatory period (P < 0.005), but not at other periods during the cycle. In high-OR gilts, progesterone was greater in the mid, late, and ovulatory phases (P < 0.005), but not in the follicular, ovulatory, and early-luteal phases. Concentrations of estradiol-17beta were not different between OR groups during the cycle. Inhibin was greater for the high OR group (P < 0.005) during the early, mid, late, luteolytic, and follicular phases (P < 0.001). The duration of the follicular phase (from last baseline estrogen value to the LH peak) was 6.5 +/- 0.5 d and was not affected by OR group. These results indicate that elevated concentrations of both FSH and LH are associated with increased ovulation rate during the ovulatory phase, but that only elevated FSH during much of the luteal phase is associated with increased ovulation rate. Of the ovarian hormones, both inhibin and progesterone are highly related to greater ovulation rates. These findings could aid in understanding how ovulation rate is controlled in pigs.