Surgery News - March 2009 - (Page 10) 10 VASCULAR MARCH 2009 • SURGERY NEWS New Tool Tested as Predictor of AAA Rupture Risk BY MITCHEL L. ZOLER Else vier Global Medical Ne ws H O L LY W O O D , F L A . — A more quantifiable and precise strategy for gauging the risk that an abdominal aortic aneurysm will rupture is on the verge of becoming a clinically useful tool. Dr. Mark F. Fillinger and his associates at Dartmouth-Hitchcock Medical Center in Lebanon, N.H., have been developing a method for measuring the vascular wall stress within abdominal aortic aneurysms (AAA) for more than 10 years. They take structural data collected by either CT or MRI to produce a three-dimensional image of a patient’s abdominal aorta and the aneurysm within it, and then factor in the patient’s peripheral blood pressure. Using both commercial software and a special program developed by Dr. Fillinger and his group, they take this information and create a mod- el showing the wall stress exerted on each square millimeter of vessel wall. AAA diameter “works pretty well” for identifying patients who have a high risk for aneurysm rupture “but it fails in some patients. What we’re trying to do is make a better differentiation” between the AAAs that will rupture and those that won’t, Dr. Fillinger said at ISET 2009, an international symposium on endovascular therapy. Because most physicians cannot read- EXAMINE THE ETHICAL UNDERPINNINGS OF THE ISSUES YOU FACE EVERY DAY A case-based educational resource for surgeons at all stages of their careers, ETHICAL ISSUES IN CLINICAL SURGERY has all the components needed to help surgeons and residents examine the ethical underpinnings of clinical practice and address the ethical issues they face every day caring for their patients Ethical Issues in Clinical Surgery was developed by the Committee on Ethics of the American College of Surgeons. TOPICS • Framework for considering ethical issues in clinical surgery • Competition of interests • Truth telling and the surgeon-patient relationship • Confidentiality • Professional obligations of surgeons • End-of-life issues • Substitute decision making FEATURES OF EACH CHAPTER • • • • • • • Realistic surgery-based cases Learning objectives Questions for discussion Analyses of cases and questions Bioethics bottom line Suggested readings Glossary and additional resources Ethical Issues in Clinical Surgery Edited by Mary H. McGrath, MD, MPH, FACS There are two versions of the book: one for course instructors and practicing surgeons that has CME credit available, and one for use with residents. Pricing and ordering information can be found at http://www.facs.org/education/ethicalissuesinclinicalsurgery.html or by calling 312/202-5335. AMERICAN COLLEGE OF SURGEONS • DIVISION OF EDUCATION ily interpret the significance of wallstress force as a raw number (in units of newtons/cm2), a recent innovation of Dr. Fillinger’s has been to translate the force into a functional diameter for each AAA. Conversion of the wall stress into a functional AAA diameter “allows us to say that the wall stress is higher or lower than is typical for a particular diameter. All clinicians know the significance when you say an aneurysm has a wall stress that’s typical for a 5.5-cm diameter AAA,” said Dr. Fillinger, an ACS Fellow, during an interview. Translating the results this way into a more easily interpretable result also “takes out the need for an expert reviewer” and may allow the measure to be more widely used, explained Dr. Fillinger, a professor of surgery at Dartmouth and program director in vascular surgery. The wall stress of “most AAAs [is] in the typical range” for the actual diameter of the aneurysms. The wall stress But in about 10%defines an AAA that is much more 20% of patients, the wall stress delikely to rupture fines an AAA that than the actual functionally diameter suggests. is much wider, and DR. FILLINGER much more likely to rupture than the actual diameter suggests. These outlier AAAs have functional diameters of 5.5 cm or greater, making them prime candidates for repair, even though their actual diameters are less than 5.5 cm, which would otherwise make them questionable repair candidates. Dr. Fillinger found the reverse situation as well. About 10%-20% of patients with AAAs that have actual diameters of 5.5 cm or greater have wall stress readings that make their functional diameter less than 5.5 cm, thereby making these aneurysms poor candidates for repair. This is especially true for patients who are old or frail, and have a relatively short life expectancy. The Dartmouth group has produced wall stress analyses for more than 300 AAAs. He anticipates evaluating the rupture predictions that his team has made for these AAAs later this year to conclusively decide if the analysis has become reliable enough for routine use. If so, they will submit their findings to the Food and Drug Administration, Dr. Fillinger said. A very similar method has been validated in a separate group of patients by researchers at Hull Royal Infirmary, England. The software that Dr. Fillinger uses to make a three-dimensional model of the patient’s abdominal aorta and the program used to calculate AAA wall stress are both commercially available. Software that eliminates artifacts has also been developed, but it has yet to be commercialized. http://www.facs.org/education/ethicalissuesinclinicalsurgery.html http://www.facs.org/education/ethicalissuesinclinicalsurgery.html
Table of Contents Feed for the Digital Edition of Surgery News - March 2009 Surgery News - March 2009 Contents Trauma Training More for Less? Stress Test Mentoring Surgery News - March 2009 Surgery News - March 2009 - Contents (Page 1) Surgery News - March 2009 - Contents (Page 2) Surgery News - March 2009 - Contents (Page 3) Surgery News - March 2009 - Contents (Page 4) Surgery News - March 2009 - Contents (Page 5) Surgery News - March 2009 - Trauma Training (Page 6) Surgery News - March 2009 - Trauma Training (Page 7) Surgery News - March 2009 - Trauma Training (Page 8) Surgery News - March 2009 - More for Less? (Page 9) Surgery News - March 2009 - Stress Test (Page 10) Surgery News - March 2009 - Stress Test (Page 11) Surgery News - March 2009 - Stress Test (Page 12) Surgery News - March 2009 - Mentoring (Page 13) Surgery News - March 2009 - Mentoring (Page 14) Surgery News - March 2009 - Mentoring (Page 15) Surgery News - March 2009 - Mentoring (Page 16)
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.