Angiographic predictors of recurrence of restenosis after Wiktor stent implantation in native coronary arteries

Intracoronary stenting has been proposed as an adjunct to balloon angioplasty to improve the immediate and long-term results. However, late luminal narrowing has been reported following the implantation of a variety of stents. One of the studies conducted with the Wiktor stent is a prospective registry designed to evaluate the feasibility, safety and efficacy of elective stent implantation in patients with documented restenosis of a native coronary artery. To identify angiographic variables predicting recurrence of restenosis, the angiograms of the first 91 patients with successful stent implantation and without clinical evidence of (sub)acute thrombotic stent occlusion were analyzed with the Computer Assisted Angiographic Analysis System using automated edge detection. The incidence of restenosis was 44% by patient and 45% by stent according to the 0.72 mm criterion, and 30% by patient and 29% by stent according to the 50% diameter stenosis criterion. The risk for restenosis for several angiographic variables was determined using an univariate analysis and is expressed as odds ratio with corresponding confidence interval. The only statistically significant predictor of restenosis was the relative gain when it exceeded 0.48 using the 0.72 mm criterion (odds ratio 2.7, 95% confidence interval 1.1-6.4). Furthermore, the relation between the relative gain (increase in minimal luminal diameter normalized to vessel size) as angiographic index of vessel wall injury and relative loss (decrease in minimal luminal diameter normalized to vessel size) as index of neointimal thickening was analyzed using a linear regression analysis. When using the categorical approach to address restenosis, there is an increased risk for recurrent restenosis when the relative gain exceeds 0.48. The continuous approach underscores this concept by indicating a weak but positive relation between the relative gain and relative loss

Recoil following Wiktor stent implantation for restenotic lesions of coronary arteries

The purpose of this study was to determine acute recoil of the vessel wall immediately after Wiktor stent implantation in native coronary arteries of 77 consecutive patients and to assess whether there was compression or “late recoil” of the stent itself at long-term follow-up. Furthermore, the relationship between recoil and a number of clinical, angiographic, and procedural variables was studied in addition to the relation between acute recoil renarrowing or restenosis was assessed. All angiograms were analyzed with the Cardiovascular Angiography Analysis System using automated edge detection. Acute recoil was defined by the difference between the mean diameter of the fully expanded balloon on which the stent was mounted and the mean diameter of the stented segment. Late recoil was calculated by comparing the mean diameter of the stent itself immediately after implantation and at follow-up without opacification of the vessel. Acute recoil amounted to 0.25 ± 0.32 mm or 8.2%. Multivariate analysis identified sex (coefficient = –0.20, p = 0.04) and stent/artery ratio (coefficient = 0.99, p = 0.0001) as the only independent predictors of acute recoil. “Late recoil” of the stent itself was not observed. The overall difference between the mean diameter of the stent itself immediately after implantation and at follow-up was –0.15 ± 0.33 mm, suggesting an overall increase in diameter of 5.0%. There was no relation between acute recoil and late restenosis. On the contrary, there was a trend towards a greater degree of recoil in patients without restenosis. Moreover, linear regression analysis disclosed a weak but negative correlation between acute recoil and a loss in minimal luminal diameter (coefficient: –0.55, p = 0.04). The Wiktor stent effectively scaffolds the instrumented vessel. Only a minimal amount of acute recoil was noted, which did not contribute to late luminal renarrowing or restenosis. In addition, no late compression of the stent itself was observed. These data suggest that tissue ingrowth into the lumen of the stented segment is the main cause of late luminal renarrowing after stent implantation. © 1994 Wiley-Liss,Inc.

The 1st Verified Software Competition, Extended Experience Report

We, the organizers and participants, report our experiences from the 1st Veried Software Competition, held in August 2010 in Edinburgh at the VSTTE 2010 conferenc

The 1st Verified Software Competition, Extended Experience Report

We, the organizers and participants, report our experiences from the 1st Veried Software Competition, held in August 2010 in Edinburgh at the VSTTE 2010 conferenc

Sound reasoning about unchecked exceptions

In most software development projects, it is not feasible for developers to handle explicitly all possible unusual events which may occur during program execution, such as arithmetic overflow, highly unusual environment conditions, heap memory or call stack exhaustion, or asynchronous thread cancellation. Modern programming languages provide unchecked exceptions to deal with these circumstances safely and with minimal programming overhead. However, reasoning about programs in the presence of unchecked exceptions is difficult, especially in a multithreaded setting where the system should survive the failure of a subsystem. We propose a static verification approach for multithreaded programs with unchecked exceptions. Our approach is an extension of the Spec # verification methodology for object-oriented programs. It verifies that objects encapsulating shared resources are always ready to be disposed of, by allowing ownership transfers to other threads only through well-nested parallel execution operations. Also, the approach prevents developers from relying on invariants that may have been broken by a failure. We believe the programming style enforced by our approach leads to better programs, even in the absence of formal verification. The proposed approach enables developers using mainstream languages to gain some of the benefits of approaches based on isolated sub-processes. We believe this is the first verification approach that soundly verifies common exception handling and locking patterns in the presence of unchecked exceptions.

Off-shore enhanced oil recovery in the North Sea:The impact of price uncertainty on the investment decisions

Although CO2 Capture and Storage (CCS) is considered a key solution for CO2 emission mitigation, it is currently not economically feasible. CO2 enhanced oil recovery can play a significant role in stimulating CCS deployment because CO2 is used to extract additional quantities of oil. This study analyzes the investment decision of both a carbon emitting source and an oil company separately by adopting a real options approach. It is shown that when uncertainty is integrated in the economic analysis, CO2 and oil price threshold levels at which investments in CO2 capture and enhanced oil recovery will take place, are higher than when a net present value approach is adopted. We also demonstrate that a tax on CO2 instead of an emission trading system results in a lower investment threshold level for the investment in the CO2 capture unit. Furthermore, we determine a minimum CO2 selling price between the two firms and show that CO2-EOR has the potential to pull CCS into the market by providing an additional revenue on the capture plant. However, when CO2 permit prices are above an identifiable level, the EU ETS does not necessarily result in the adoption of CCS and stimulates oil production

Explorative study on patients' perceived knowledge level, expectations, preferences and fear for side effects for treatment for allergic rhinitis

ABSTRACT: BACKGROUND: In spite of the high prevalence of allergic rhinitis (AR) and the evidence-based guidelines for treatment, little is known about the patients' perceived knowledge level, expectations, preferences for treatment, and fear for side effects of treatment for AR. These factors may influence adherence to treatment and determine the success of therapy. METHODS: This cross-sectional survey study included a convenience sample of 170 patients with rhinitis and clinical suspicion of allergy at the department of Otorhinolaryngology and Allergology. Patients' perceived knowledge level, expectations, patient preferences, and fear of side effects of allergy treatment were collected via a self-report questionnaire developed for the purpose of this study. RESULTS: 22% of all patients (38/170) reported to have knowledge about anti-allergic treatment. 40% (55/170) of rhinitis patients expected to be cured by the prescribed treatment, whereas 43% (73/170) of patients expected suppression of allergic symptoms. Nasal spray was the preferred route of anti-allergic drug administration in 30% (52/170) of patients, followed by oral treatment (24%; 42/170), combination therapy (16%; 30/170), and injection therapy (15%; 27/170). More patients would choose a combination treatment with step-down approach (31%; 53/170) than mono-therapy with a step-up approach (20%; 34/170). Fear for side effects was reported mainly for nasal corticosteroids (48%; 81/170) and less for oral antihistamines (33%; 36/170), leucotriene antagonists (21%, 36/170) and immunotherapy (19%, 33/170). CONCLUSIONS: Patients consulting for rhinitis have high expectations of anti-allergic treatment, prefer a nasal spray above oral treatment, prefer combined treatment rather than monotherapy, and fear adverse events of anti-allergic treatment.status: publishe