Flow patterns through vascular graft models with and without cuffs.

The shape of a bypass graft plays an important role on its efficacy. Here, we investigated flow through two vascular graft designs-with and without cuff at the anastomosis. We conducted Digital Particle Image Velocimetry (DPIV) measurements to obtain the flow field information through these vascular grafts.

Flow bioreactor design for quantitative measurements over endothelial cells using micro-particle image velocimetry.

Mechanotransduction in endothelial cells (ECs) is a highly complex process through which cells respond to changes in hemodynamic loading by generating biochemical signals involving gene and protein expression. To study the effects of mechanical loading on ECs in a controlled fashion, different in vitro devices have been designed to simulate or replicate various aspects of these physiological phenomena. This paper describes the design, use, and validation of a flow chamber which allows for spatially and temporally resolved micro-particle image velocimetry measurements of endothelial surface topography and stresses over living ECs immersed in pulsatile flow.

Dual use of amphiphilic macromolecules as cholesterol efflux triggers and inhibitors of macrophage athero-inflammation.

Activated vascular wall macrophages can rapidly internalize modified lipoproteins and escalate the growth of atherosclerotic plaques. This article proposes a biomaterials-based therapeutic intervention for depletion of non-regulated cholesterol accumulation and inhibition of inflammation of macrophages. Macromolecules with high scavenger receptor (SR)-binding activity were investigated for SR-mediated delivery of agonists to cholesterol-trafficking nuclear liver-X receptors.

Convergence of nanotechnology and cardiovascular medicine : progress and emerging prospects.

Advances in the emergence of biological probes, materials, and analytical tools limited to the nanoscale size range, collectively referred to as 'nanotechnology', are increasingly being applied to the understanding and treatment of the major pathophysiological problems in cardiovascular medicine. Analytical techniques based on high-resolution microscopy and molecular-level fluorescence excitation processes capable of detecting nanoscale interactions have been used to elucidate cardiovascular pathology. Nanotechnology has also significantly impacted diagnostic intervention in cardiology, with the use of nanoparticles as contrast agents, for targeted biomedical imaging of vulnerable plaques, for detection of specific pathologic targets signaling the onset of atherosclerosis, and for tracking inflammatory events.

Iodine inhibits antiadhesive effect of PEG: implications for tissue engineering.

Background: The success of a biomaterial implant may be affected by the surface chemistry's impact on protein adsorption. We have developed a series of poly(ethylene glycol) (PEG) containing, tyrosine-derived polycarbonates, which have been rendered radio-opaque by the iodination of tyrosine units in the copolymer backbone for use in resorbable biomedical implants including vascular stents and grafts. We tested the hypothesis that protein adsorption along with seeding, growth, and migration of human aortic smooth muscle cells (SMC) and human aortic endothelial cells (EC) will be modified by the presence of iodine and PEG within the polymer composition.

Inhibition of apoptosis prevents shear-induced detachment of endothelial cells.

Background: Biomaterials placed into the vasculature in man fail to develop an endothelial lining. Attempts to seed endothelial cells (ECs) on prosthetic vascular grafts have failed due to flow-induced detachment. The mechanism of flow-induced detachment of ECs from biomaterials is undefined.

Implementation of a novel web-based objective structured clinical evaluation.

Background: This study was performed to identify factors that impact student performance on a web-based objective structured clinical evaluation (OSCE) that was developed to improve the evaluation process of students who complete a fourth-year surgical clerkship in trauma-critical care.

Methods: We created a multiple-choice OSCE with commercially available software. Clinical cases were developed for incorporation into 7 quizzes that were assembled to appear as 1 examination.

Factors impacting functional health and resource utilization following abdominal aortic aneurysm repair by open and endovascular techniques.

We assessed the impact on patient outcomes of comorbidities and type of aneurysm repair, open vs. endovascular aortic repair (EVAR). Functional health status was measured prospectively using the Short Form 36 (SF-36) Health Survey.

Resource utilization and outcomes: effect of transfer on patients with ruptured abdominal aortic aneurysms.

We evaluated the transfer of patients with the diagnosis of a ruptured AAA (rAAA) from community centers to a tertiary care center. Our purpose was to identify factors associated with mortality and outcomes following the open repair of rAAA and to evaluate the differences between transferred and nontransferred patients. All patients who underwent repair of rAAA at our institution between 1995 and 2002 were retrospectively reviewed.

Perirenal fixation as an independent factor in aortic remodeling after endovascular aortic aneurysm repair.

The purpose of our study was to evaluate the influence of perirenal fixation of endovascular aortic grafts on the rate of endoleak and aortic sac remodeling. Retrospective analysis of all patients (pts.) after undergoing endovascular aortic aneurysm repair (EVAR) at our institution was performed.

Effective use of human simulators in surgical education.

Background: We initiated a teaching module utilizing a human simulator midway through 2001-2002 to improve student skills specific to the evaluation of patients in shock during a required clerkship in surgery for fourth-year medical students. We tested the hypothesis that student skills would improve after implementation of this module and identified factors that predicted student performance.

Materials And Methods: Students (n = 86) chose one of two hospital sites for a clerkship that focuses on the care of acutely ill surgical patients.

Efficacious use of nitinol stents in the femoral and popliteal arteries.

Objective: To evaluate the performance and identify predictors of outcome after the use of self-expanding nitinol stents in the treatment of femoropopliteal arterial occlusive disease.

Methods: A retrospective analysis of a prospectively collected database was performed. Outcomes of patients who underwent placement of a nitinol stent in the femoral or above-knee popliteal arteries between 1999 and 2002 were studied.

Influence of endovascular training on fellowship and general surgical training.

Purpose: As endovascular procedures develop, there is a risk of diminished training of residents and fellows in traditional open surgery. We evaluated the effect of our endovascular program, initiated in 1999 coincident with the Federal Drug Administration's approval of endoluminal vascular aortic grafts, on the number of endovascular procedures and open abdominal aortic aneurysm (AAA) repairs performed in comparison to national trends.

Methods: The experience of vascular fellows and chief residents at completion of training (1996-2002) was reviewed and compared with the national mean case numbers before and after initiation of our endovascular program.

Predictors of educational outcome: factors impacting performance on a standardized clinical evaluation.

Background: To improve student skills specific to the evaluation of radiology studies during a required clerkship in surgery for 4th-year medical students, we initiated a self-study CD-ROM educational module midway through 2000-2001. We hypothesized that student performance would improve after implementation of this module and identified factors that predicted student performance.

Materials And Methods: Students (n = 98) chose one of two hospital sites for a clerkship that focuses on the care of acutely ill surgical patients.