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Biomedical subjects

William C Pevec

Publications and source records attributed to William C Pevec.

4 recordsLinked to original sources

Vascular surgery: an update.

Caring for patients with vascular illnesses has become increasingly more complex and has changed dramatically over the past 10 years, with a widening array of diagnostic and treatment options. Carotid artery stenting has the potential to become a viable alternative to open surgery in high-risk patients with carotid artery disease (i.e., patients older than 80 years and those with previous neck surgery or irradiation, contralateral carotid artery occlusion, contralateral laryngeal nerve injury, or angina). However, the effectiveness of carotid artery stenting as a therapy is still being evaluated in randomized trials. Endovascular aortic aneurysm repair is an option for patients who desire or require a less invasive modality and who have suitable aortic anatomy. Surgical reconstruction remains the standard treatment for ischemic rest pain and tissue loss (critical limb ischemia). Balloon angioplasty and stenting are treatment options for peripheral vascular disease, although treatment is dependent on the arterial segment or segments involved.

Aortic Aneurysm, Abdominal↗

Training with simulation improves residents' endovascular procedure skills.

BACKGROUND: Endovascular procedure simulators are now commercially available and in use for physician training. The purpose of this study was to evaluate the role of simulation-based training in vascular surgery residencies. METHODS: Residents from vascular surgery programs in a five-state area were invited to participate in a series of 2-day endovascular training programs that used a high-fidelity endovascular procedure simulator (SimSuite; Medical Simulation Corporation, Denver, Colo), didactic instruction, computer-based training, and tabletop procedure demonstrations. The curriculum covered arteriography and intervention for treatment of aortoiliac, renal, and carotid artery disease. Nine residents participated, with one to three per training session. Each completed an average of 9.5 simulated endovascular cases. Performance on a standardized TransAtlantic Inter-Society Consensus B iliac angioplasty/stenting case was used to assess endovascular skills and knowledge at the beginning of the training program, and this was repeated at the completion of the training. Performance metrics were measured by the simulator, faculty observed trainees' performance of simulated cases, and trainees provided their evaluations of the usefulness of the simulation experiences. RESULTS: Endovascular procedural skills on the standardized iliac intervention case improved after completion of the training program. Compared with performance early on day 1, performance improved (P < or = .05; paired t test): total procedure time decreased 54%, volume of contrast decreased 44%, and fluoroscopy time decreased 48% (mean change from baseline). Selection of angioplasty balloon catheters and stents was improved, and the average number of catheters used and stents deployed decreased, although this did not reach statistical significance. Faculty observation allowed identification of shortcomings of knowledge and skills, including common problems with selection of catheter, balloon, and stent sizes; correct positioning of the sheath; and intraprocedural monitoring. Postcourse evaluations indicated support for the use of simulation in vascular surgery residents' endovascular training. CONCLUSIONS: Training with a simulator, incorporated into an individual or small group learning session, offers a means to learn and realistically practice endovascular procedures without direct risk to patients, with measurable improvements in key performance metrics. How simulation training affects subsequent clinical performance has yet to be established.

Endoscopy↗

Effects of brachytherapy on intimal hyperplasia in arteriovenous fistulas in a porcine model.

PURPOSE: The hypotheses of this investigation were that endovascular radiation would reduce intimal hyperplasia in arteriovenous fistulas (AVFs) and that this reduction would be associated with decreased expression of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF)-A, and tumor necrosis factor (TNF)-alpha. MATERIALS AND METHODS: Bilateral end jugular vein-to-side carotid artery fistulas were constructed in pigs. At 48 hours, one AVF was randomly selected for endovascular radiation with (192) Iridium. The contralateral fistula received no radiation and served as a control. Animals in group 1 (n = 7) received 14 Gy of radiation at a depth of 2 mm and tissue was harvested at 29 days; animals in group 2 received 7 Gy of radiation at a depth of 2 mm and tissue was harvested at 29 days (n = 8); and animals in group 3 received 7 Gy of radiation at a depth of 2 mm and tissue was harvested at 56 days (n = 8). The area and maximum thickness of intimal hyperplasia were then measured blindly. Immunohistochemical results for VEGF, PDGF-A, and TNFalpha were obtained and analyzed blindly by assigning a score of 0-3, with 0 indicating no staining and 3 indicating maximum staining. RESULTS: Irradiation with 14 Gy caused severe fibrosis in the media of the vein, with thrombosis of three of seven AVFs. Compared with the control group, the group that underwent irradiation with 7 Gy had significantly reduced intimal area at 56 days (9.9 mm(2) +/- 4.9 vs 2.1 mm(2) +/- 1.1; P =.001). This reduction correlated with significant reduction in the expression of VEGF (score of 2.2 +/- 0.1 vs 1.2 +/- 0.2; P =.001) and TNFalpha (1.3 +/- 0.1 vs 0.9 +/- 0.1; P =.04). CONCLUSION: Fourteen grays is an excessive radiation dose for veins, causing medial fibrosis and thrombosis of the AVF. Irradiation with 7 Gy effectively inhibited the formation of intimal hyperplasia in AVF. This inhibition correlated with decreased expression of VEGF and TNFalpha.

Animals↗