Is population screening for abdominal aortic aneurysm cost-effective?

<p>Abstract</p> <p>Background</p> <p>Ruptured abdominal aortic aneurysm (AAA) is responsible for 1–2% of all male deaths over the age of 65 years. Early detection of AAA and elective surgery can reduce the mortality risk associated with AAA. However, many patients will not be diagnosed with AAA and have therefore an increased death risk due to the untreated AAA. It has been suggested that population screening for AAA in elderly males is effective and cost-effective. The purpose of this study was to perform a systematic review of published cost-effectiveness analyses of screening elderly men for AAA.</p> <p>Methods</p> <p>We performed a systematic search for economic evaluations in NHSEED, EconLit, Medline, Cochrane, Embase, Cinahl and two Scandinavian HTA data bases (DACEHTA and SBU). All identified studies were read in full and each study was systematically assessed according to international guidelines for critical assessment of economic evaluations in health care.</p> <p>Results</p> <p>The search identified 16 cost-effectiveness studies. Most studies considered only short term cost consequences. The studies seemed to employ a number of "optimistic" assumptions in favour of AAA screening, and included only few sensitivity analyses that assessed less optimistic assumptions.</p> <p>Conclusion</p> <p>Further analyses of cost-effectiveness of AAA screening are recommended.</p

Relaxed Balance for Search Trees with Local Rebalancing

Search trees with relaxed balance were introduced with the aim of facilitating fast updating on shared-memory asynchronous parallel architectures. To obtain this, rebalancing has been uncoupled from the updating, so extensive locking in connection with updates is avoided. Rebalancing is taken care of by background processes, which do only a constant amount of work at a time before they release locks. Thus, the rebalancing and the associated locks are very localized in time as well as in space. In particular, there is no exclusive locking of whole paths. This means that the amount of parallelism possible is not limited by the height of the tree. Search trees with relaxed balance have been obtained by adapting standard sequential search trees to this new paradigm; clearly using similar techniques in each case, but no general result has been obtained. Recent developments in the area, however, have prepared the way for the present paper, where we demonstrate that any search tree with local..

Relaxed Balance through Standard Rotations

We consider binary search trees, where rebalancing transformations need not be connected with updates but may be delayed. For standard AVL tree rebalancing, we prove that even though the rebalancing operations are uncoupled from updates, their total number is bounded by O(M log(M+N)), where M is the number of updates to an AVL tree of initial size N. Hence, relaxed balancing of AVL trees comes at no extra cost asymptotically. Furthermore, our scheme differs from most other relaxed balancing schemes in an important aspect: No rebalancing transformation can be done in the wrong direction, i.e., no performed rotation can make the tree less balanced. Moreover, each performed rotation indeed corresponds to a real imbalance situation in the tree. Our results are important in designing efficient concurrency control strategies for main-memory databases. Main-memory search structures have gained new applications in large embedded systems, such as switching systems for mobile telephones