Automated software supported versus manual aorto-iliac diameter measurements in CT angiography of patients with abdominal aortic aneurysms: assessment of inter- and intraobserver variation.

BACKGROUND: Open surgical or endovascular abdominal aortic aneurysm (AAA) relies on precise preprocedual imaging. Purpose of this study was to assess inter- and intraobserver variation of software-supported automated and manual multi row detector CT angiography (MDCTA) in aortoiliac diameter measurements before AAA repair. PATIENTS AND METHODS: Thirty original MDCTA data sets (4 x 2mm collimation) of patients scheduled for endovascular AAA repair were studied on a dedicated software capable of creating two-dimensional reformatted planes orthogonal to the aortoiliac center-line. Measurements were performed twice with afour-week interval between readings. Data were analysed by two blinded readers at random order Two different measurement methods were performed: reader-assisted freehand wall-to-wall measurement and semi-automatic measurement. RESULTS: Aortoiliac diameters were significantly underestimated by the semi-automatic method as compared to reader-assisted measurements (p < 0.0031). Intraobserver variability of AAA diameter calculation was not significant (p > 0. 15) for reader-assisted measurements except for the diameter of the left common iliac artery in reader 2 (p = 0.0045) and it was not significant (p > 0. 14) using the semi-automatic method. Interobserver variability was not significant for AAA diameter measurements using the reader-assisted method and for proximal neck analysis with the semiautomatic method (p > 0.27). Relevant interobserver variation was observed for semi-automatic measurement of maximum AAA (p = 0.0007) and iliac artery diameters (p = 0.024). CONCLUSIONS: Dedicated MDCTA software provides a useful tool to minimize aortoiliac diameter measurement variation and to improve imaging precision before AAA repair. For reliable AAA diameter analysis the reader-assisted freehand measurement method is recommended to be applied to a set of reformatted CT data as provided by the software used in this study.

Intermediate outcome and risk factor assessment of bovine vascular heterografts used as AV-fistulas for hemodialysis access.

OBJECTIVES: This observational study was set up to prospectively follow all bovine heterograft (ProCol) fistulas implanted for hemodialysis access between 1998 and 2002. METHODS: ProCol was implanted if autogenous vein was not available or if patients presented with a history of failed, infected or otherwise complicated ePTFE grafts and/or on immunosuppressive therapy. Fistula patency was the primary outcome; secondary outcomes were clinical events and the rate of access revisions. RESULTS: Sixty-two ProCol grafts were implanted in 56 patients. The mean primary (PP) and secondary patency (SP) was 334 (SEM 57) and 528 (SEM 59) days, respectively. Coronary heart disease was associated with a significantly better SP (OR 0.2, 95% CI 0.1-0.9) whilst diabetes mellitus was associated with a significantly worse SP (OR 0.2, 95% CI 0.1-0.9). Reinterventions were performed at a mean rate of 1.23 (SEM 0.17) per fistula. The relative risk of access revision was significantly higher in patients with diabetes mellitus (OR 9.2, 95% CI 2.3-37.2). CONCLUSIONS: ProCol grafts, used for AV-fistulas, demonstrate acceptable patency rates in high-risk haemodialysis patients. Diabetes mellitus jeopardizes the patency of these fistulas and is associated with a high revision rate.

[Endovascular treatment of the abdominal aortic aneurysm: assessment, implantation technique, after-care and results]. / Endovaskuläre Behandlung des Bauchaortenaneurysmas: Abklärung, Implantationstechnik, Nachbetreuung und Resultate.

BACKGROUND: Endovascular treatment of abdominal aortic aneurysm (AAA) is a new minimally invasive alternative to surgical repair. Patient selection, perioperative management, the procedure itself and postoperative follow-up are new aspects. PATIENTS: From June 1997 to June 1998, 37/70 patients (53%) with AAA were treated by the endovascular method. There were 35 males and two females, mean age 74 +/- 7 years, with a mean ASA class of 3.5 +/- 0.5. Graft repair was performed in 33 patients, due to inappropriate aortic anatomy for the endovascular technique in 24 and leaking aneurysm in 9. METHODS: Feasibility is based upon computed tomography and angiography. The procedure was performed in the operating room, under general, regional and local anaesthesia in 14, 3 and 20 patients, respectively. 36 bifurcated and one tube endoprosthesis were implanted. An open access on one femoral or iliac artery and, in case of bifurcated prosthesis, usually a percutaneous access (10 Fr) on the other side were performed. Positioning and delivery were monitored under fluoroscopy. RESULTS: All the AAA could be sealed by the endovascular technique. In one patient, an iliac limb was removed surgically because of proximal misplacement, but the procedure was completed by the endovascular technique. Mean operation time was 140 +/- 67 minutes. ICU stay was 1.4 +/- 1.6 days and patients were discharged after 6.5 +/- 3.5 days. Postoperative radiological follow-up showed totally sealed aneurysms in 34/37 patients (91%). In 3 patients a residual perfusion originating from a lumbar artery was observed. In 7/14 patients with AAA diameter > 6 cm and without residual leakage on the control CT scan, aneurysm pulsation remained after endovascular treatment. There was no early or late death after endovascular repair. During the follow-up period of 4 +/- 3 months patients are doing well. One patient needed balloon dilatation of an iliac limb. CONCLUSIONS: Endovascular treatment of AAA is a minimally invasive technique with short recovery time. This technique seems to be particularly advantageous in elderly or severely ill patients. Long-term controls are mandatory to identify potential complications, particularly when residual perfusion or aneurysm pulsation persists.