The impact of radiation dose exposure during endovascular aneurysm repair on patient safety.

OBJECTIVE: Endovascular aneurysm repair (EVAR) exposes patients to radiation during the procedure and in subsequent follow-up. The study goal was to calculate the radiation dose in our unit and compare it against other published data and national guidelines. METHODS: All EVAR procedures were identified from a prospectively maintained database. Radiation dose, screening time, and volume of intravenous contrast during the procedure were reviewed. Radiation exposure from subsequent computed tomography (CT) imaging was included in the overall exposure. Results are expressed as mean +/- standard deviation. RESULTS: From October 1998 to October 2008, 320 elective patients underwent EVAR. Mean screening time was 29.4 +/- 23.3 minutes, and the radiation dose was 11.7 +/- 7.1 mSv. The EVAR was an emergency in 64 patients. The mean screening time was 22.9 +/- 18.2 minutes, and the radiation dose was 13.4 +/- 8.6 mSv. During the first postoperative year, follow-up CT scans exposed the patients to 24.0 mSv, with 8.0 mSv in subsequent years. Abdominal radiographs added an additional 1.8 mSv each year. CONCLUSION: EVAR and the follow-up investigations involve substantial amounts of radiation, with well-recognized carcinogenic risks. Because patient safety is paramount, radiation exposure should be minimized. This may be possible by standardizing radiation exposure throughout the United Kingdom by implementing national guidelines and considering other imaging modalities for follow-up.

Using GIS for spatial analysis of rectal lesions in the human body.

BACKGROUND: Geographic Information Systems (GIS) have been used in a wide variety of applications to integrate data and explore the spatial relationship of geographic features. Traditionally this has referred to features on the surface of the earth. However, it is possible to apply GIS in medicine, at the scale of the human body, to visualize and analyze anatomic and clinical features. In the present study we used GIS to examine the findings of transanal endoscopic microsurgery (TEM), a minimally-invasive procedure to locate and remove both benign and cancerous lesions of the rectum. Our purpose was to determine whether anatomic features of the human rectum and clinical findings at the time of surgery could be rendered in a GIS and spatially analyzed for their relationship to clinical outcomes. RESULTS: Maps of rectal topology were developed in two and three dimensions. These maps highlight anatomic features of the rectum and the location of lesions found on TEM. Spatial analysis demonstrated a significant relationship between anatomic location of the lesion and procedural failure. CONCLUSION: This study demonstrates the feasibility of rendering anatomical locations and clinical events in a GIS and its value in clinical research. This allows the visualization and spatial analysis of clinical and pathologic features, increasing our awareness of the relationship between anatomic features and clinical outcomes as well as enhancing our understanding and management of this disease process.

Advantages and pitfalls of abdominal aortic aneurysm screening in high-risk patients.

Screening for abdominal aortic aneurysm (AAA) has been suggested for older men. Our aim was to determine the effect of participant selection on prevalence and treatment suitability. Men aged 65 to 75 years attending cardiology clinics composed the high-risk group; the control group was from the community. AAA screening was performed, with follow-up or surgery arranged. Four hundred eight of 651 (62.7%) high-risk men and 109 of 908 (45.0%; p< .0001) men attended from the community. In the high-risk patients, 40 AAAs were diagnosed, with a mean diameter of 41.4 mm (+/-10.4 mm). In the control group, 22 new AAAs were found, with an average size of 40.9 mm (+/-10.4 mm). Higher polypharmacy existed in the high-risk group (4.6+/-2.2 vs 2.3+/-2.0; p< .0001). More aneurysm patients were on dual-antiplatelet therapy (32.5% vs 15.4%; p= .048) compared with the overall high-risk group. In this group, three underwent surgery; one was anatomically unsuitable for endovascular repair and medically unfit for open repair. Two in the control group had surgery. A higher prevalence of AAA is encountered in high-risk men. Most aneurysms are small; however, a significant proportion of the aneurysms detected were of a size that would warrant repair. The decision to perform surgical repair is likely to be influenced by the comorbid medical conditions, which placed the patients in the high-risk category.

Risk factors for abdominal aortic aneurysm and the influence of social deprivation.

INTRODUCTION: the objective of this abdominal aortic aneurysm (AAA) screening study was to determine attendance and disease prevalence patterns in Northern Ireland and the role of deprivation and other risk factors. PATIENTS AND METHODS: patients from primary care practices from Belfast, Lisburn, and Saintfield were screened. Past medical history and deprivation details were determined. RESULTS: 2264 men from Belfast, 1104 men in Lisburn, and 284 in Saintfield were invited to attend. Overall, 1659 (45.3%) men attended, with 40.6% from Belfast, 55.0% from Lisburn, and 45.8% from Saintfield (P < .0001). Ninety-two (5.5%) new AAAs were diagnosed, with 6.5%, 3.8%, and 6.2% in the 3 areas (P = .055). As deprivation decreased, attendance increased and prevalence decreased. Smoking, peripheral arterial disease, number of medications prescribed, and geographical origin were independent risk factors for AAAs. CONCLUSION: aneurysm prevalence is influenced by geographical origin and deprivation, which should, therefore, be important factors in health care planning and screening provision.