![]() ![]() This was represented by a sharp increase in the CUSUM curve until ∼35 procedures. Technical failures accumulated at the beginning. In terms of the primary endpoint, 30-day technical success, the CUSUM graph clearly indicated a learning effect. 1) but due to the small absolute numbers, this trend was not statistically significant. The incidence of complications decreased with increasing experience ( n = 4 vs. This was accompanied by a significant increase in intervention and fluoroscopy time in group 3 after the intervention time had decreased with increasing experience from group 1 to group 2. There was a trend toward performing more complex procedures among the last third of patients, with a particular increase in the number of additional procedures such as hypogastric artery embolization. Finally, procedural details were also analyzed for differences among groups.īDeemed positive when one of the following parameters was fulfilled: neck length 27 mm neck angle > 60° severe circumferential calcification and inverse funnel-shaped neck. In addition, baseline demographic and clinical parameters were compared with investigate trends in patient selection for EVAR versus open repair. The results of the first group were compared with the later groups under the assumption that a learning curve would be reflected in significantly inferior results among patients in the first group. Group 1 included 34 patients treated between January 2001 and August 2004 group 2 included 34 patients treated between September 2004 and March 2007 and group 3 included 33 patients treated between April 2007 and January 2010. Subsequently, the whole cohort was divided into three groups of equal size based on treatment date. A CUSUM test including alert and alarm boundaries was not applied because, in our opinion, the arbitrary constitution of boundaries is not appropriate in the retrospective setting. Hence, a rise of the CUSUM curve over the straight reference line indicates an increased failure rate in the corresponding time. Both lines end at 6.9%, which was the actual final failure rate in our study. For comparison, a straight line representing a constant failure distribution was drawn. Successes are represented by flat sections of the line. 6 This curve may be easily interpreted visually because it rises with every failure. To retrospectively analyze the learning curve, we applied a describing CUSUM graph. It has been used in the analysis of learning curves of medical procedures by other authors 2, 3 and is well suited to analyze a learning curve of vascular and endovascular procedures. This method was developed as a mathematical tool for quality control. To display the learning curve of this parameter, the cumulative sum (CUSUM) method was used. ![]() The 30-day technical success rate, which was exactly identical to the 30-day clinical success rate in our cohort, was analyzed as the primary endpoint. Gore Inc., Flagstaff, AZ), the results of the 101 patients treated with the Zenith stent graft between January 2001 and January 2010 were retrospectively analyzed to look for the presence and configuration of a learning curve. The clear increase in the overall numbers (diamonds) is predominantly a result of the increasing number of endovascular procedures.Īfter exclusion of five patients treated with an Excluder stent graft (L.W. In the last 3 years, this trend has reversed. The quadrates represent the number of open repairs, which declined since the introduction of endovascular repair (triangles). The number of electively treated AAAs in our institution within the past 15 years. The purpose of the present study was to report the learning curve of Zenith stent graft–based EVAR procedures and to analyze recent trends in the management of AAA patients in a nonacademic vascular center. We also examined the incidence of aneurysms, demographic/anatomic characteristics of the patients, and changes in indication for EVAR. We now analyzed the results of all patients treated with a Zenith stent graft to look for the presence of a learning curve. The Zenith graft was used in 101 of 106 procedures performed in the last 9 years. Since the year 2001, the Zenith stent graft (Cook Medical Inc., Bloomington, IN) was the device of choice for EVAR at our institution. However, EVAR is a rather sophisticated procedure, and in addition to the risk of major complications, various problems can cause technical or clinical failure in the short or long term. Since stent grafts have become commercially available, EVAR has been widely adopted because of its minimally invasive character and low operative risk. Endovascular aneurysm repair (EVAR) was introduced in the 1990s as a less invasive treatment option for high-risk abdominal aortic aneurysm (AAA) patients. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |