Showing papers by "Michael Collins published in 2006"

Treatment of coronary artery perforations complicating percutaneous coronary intervention with a polytetrafluoroethylene-covered stent graft.

Abstract: Coronary artery perforation is a rare, but dreaded, complication of percutaneous coronary intervention. Conventional treatment, including reversal of anticoagulation and prolonged balloon inflation, is associated with a high incidence of death, Q-wave myocardial infarction, and emergency coronary bypass surgery. Although a number of case reports have demonstrated the feasibility of sealing coronary perforations with synthetic material-covered stent grafts, the efficacy of this treatment has not been reported in a large, multicenter series. We used a retrospective international registry to examine the outcomes of the polytetrafluoroethylene-coated JOSTENT coronary stent graft (CSG) in 41 cases of coronary perforations. Perforations were relatively severe: 16.7% Ellis grade 1, 54.2% grade 2, and 29.1% grade 3. Of the 41 patients, >1/3 (n = 14) experienced life-threatening complications before stent graft implantation, including pericardial tamponade (12.2%), cardiogenic shock (9.8%), and cardiac arrest (2.4%). A total of 52 CSGs were used to treat the 41 perforations (mean 1.3 per lesion). All CSGs were placed successfully, with 92.9% of the perforations sealed completely and 7.1% partially. One patient developed abrupt vessel closure after CSG deployment, resulting in an overall procedure success rate of 96.4%. No in-hospital Q-wave myocardial infarctions, emergency coronary bypass surgeries, or deaths resulted. The CSG may be a reliable and highly effective treatment option for sealing coronary perforations complicating percutaneous coronary interventions.

A Discriminative Model for Tree-to-Tree Translation

Abstract: This paper proposes a statistical, tree-to-tree model for producing translations. Two main contributions are as follows: (1) a method for the extraction of syntactic structures with alignment information from a parallel corpus of translations, and (2) use of a discriminative, feature-based model for prediction of these target-language syntactic structures---which we call aligned extended projections, or AEPs. An evaluation of the method on translation from German to English shows similar performance to the phrase-based model of Koehn et al. (2003).

A multicenter, randomized, dose-finding study of gamma intracoronary radiation therapy to inhibit recurrent restenosis after stenting.

Abstract: Objectives. The objective of this double-blind, randomized study was to determine the safety and efficacy of intracoronary radiation therapy (ICRT) with a dose of 17 Gray (Gy) compared to the currently recommended dose prescription of 14 Gy for the treatment of in-stent restenosis within bare metal stents. Background. While gamma ICRT for in-stent restenosis has been proven efficacious, the optimal dose is unknown, and radiation failure due to recurrent neointimal hyperplasia remains a significant clinical problem for some patients. A higher radiation dose may improve outcomes, but may potentially increase adverse events. Methods. Following coronary intervention, 336 patients with in-stent restenosis were randomly assigned to receive ICRT with either 14 Gy or 17 Gy at 2 mm from an 192-iridium source. Results. At 8-month follow up, fewer patients in the 17 Gy group underwent target lesion revascularization (TLR = 15.2% versus 27.2%; p = 0.01), target vessel revascularization (21.3% versus 33.1%; p = 0.02), or reached the composite endpoint of death, myocardial infarction, thrombosis, or TLR (17.1% versus 28.4%; p = 0.02). There were no differences in late thrombosis or mortality between treatment groups. There was a strong trend toward reduced in-lesion late loss (0.36 ± 0.63 mm vs. 0.51 ± 0.64 mm; p = 0.09) and a significantly lower rate of binary restenosis (23.9% versus 38.1%; p = 0.031) in the high dose group. Conclusions. Gamma ICRT with 17 Gy is safe and, compared to 14 Gy, reduces recurrent stenosis and clinical events at 8-month follow up. An increase in the currently recommended gamma radiation dose prescription from 14 Gy to 17 Gy should be strongly considered.