Supplemental oxygen reverses hypoxia-induced smooth muscle cell proliferation by modulating HIF-alpha and VEGF levels in a rabbit arteriovenous fistula model.

Background: Numerous mechanisms for the formation of intimal hyperplasia have been proposed but none have been proven or accepted. Our research focuses on the potential role of hypoxia-inducible factors (HIFs), vascular endothelial growth factor (VEGF), and platelet-derived growth factors as well as the extracellular signal-regulated kinase (ERK), phosphatidylinositide 3-kinase /protein Kinase B (PI3-K/AKT) pathway in hypoxia-mediated intimal hyperplasia processes. We hypothesize that HIF and VEGF will be downregulated with supplemental oxygen in our arteriovenous fistula rabbit model.

Removal of an infected aortic endograft and open aortic reconstruction: technical remarks.

Infection of an aortic endoprosthesis is a potentially lethal complication of an endovascular abdominal aortic aneurysm repair (EVAR). Surgical treatment usually involves excision of the infected endograft and vascular reconstruction, either in-line or extraanatomic. We present a case of severe infection of an endograft with suprarenal fixation.

The role of short-term oxygen administration in the prevention of intimal hyperplasia.

Objective: Intimal hyperplasia (IH) is the cause of most failed arteriovenous fistulas (AVFs), resulting in repeat procedures and leading to increased utilization of scarce health care resources. Our laboratory has previously demonstrated the role of supplemental oxygen in preventing IH and smooth muscle cell proliferation (SMCp) at an artery-to-graft anastomosis and at the deployment site of an intra-arterial stent. This study examines the effect of supplemental oxygen in preventing IH and SMCp in an AVF in a rabbit model.

Prognostic value of 12-lead electrocardiogram and peak troponin I level after vascular surgery.

Objective: The aim of this investigation was to determine if the presence of ischemic electrocardiographic (ECG) changes in patients undergoing vascular surgery provides incremental prognostic information about the long-term risk of death compared with a single peak troponin level within 48 hours after surgery.

Methods: This was a retrospective analysis of 337 patients undergoing moderate-risk to high-risk vascular surgery at our institution whose ECG and biomarker data were complete. Peak cardiac troponin (cTn) I values that exceeded the upper reference limit (URL) were categorized as low-positive (+), at or exceeding the URL but less than three times the URL, or high-positive (+), at or exceeding three times the URL.

Hypoxia differentially regulates arterial and venous smooth muscle cell proliferation via PDGFR-β and VEGFR-2 expression.

Despite intensive research studies, theories have yet to focus on the contribution of hypoxia to patency differences observed clinically between arterial vs. venous grafts. This study investigates the differential hypoxic response of smooth muscle cells (SMC) to hypoxia-derived endothelial cell (EC) growth factors.

Peak postoperative troponin levels outperform preoperative cardiac risk indices as predictors of long-term mortality after vascular surgery Troponins and postoperative outcomes.

Background: The utility of postoperative troponins as an independent predictor of long-term mortality after vascular surgery is unknown.

Methods: One hundred sixty-four consecutive patients underwent vascular surgery and postoperative mortality was determined at 2.5 years.

Preoperative coronary artery revascularization and long-term outcomes following abdominal aortic vascular surgery in patients with abnormal myocardial perfusion scans: a subgroup analysis of the coronary artery revascularization prophylaxis trial.

Background: Abdominal aortic operations have the highest perioperative cardiac risk. To test the impact of preoperative coronary artery revascularization (PR) in this high-risk subset, a post hoc analysis was performed in patients undergoing aortic surgery within the Coronary Artery Revascularization Prophylaxis (CARP) trial.

Methods: The study cohort was a subset of 109 CARP patients with myocardial ischemia on nuclear imaging randomized to a strategy of PR (N = 52) or no PR (N = 57) before their scheduled abdominal aortic vascular operation.

Radial artery pseudoaneurysm in the intensive care unit.

Pseudoaneurysms may occur at the wrist after catheterization of the radial artery but may also occur after arteriovenous shunting for dialysis or after direct trauma to an artery. Radial artery pseudoaneurysms are being increasingly reported because of widespread use of invasive monitoring. We report a case of radial artery pseudoaneurysm at the wrist related to catheterization.

Current issues facing academic surgery departments: stakeholders' views.

Purpose: To determine the issues important to stakeholders in today's academic surgery departments, to query key stakeholders about possible solutions, and to investigate the correlation of organizational alignment among department stakeholders with department performance.

Method: Between July 2003 and October 2005, the author designed, piloted and carried out a study in which he interviewed key stakeholders-deans, chief executive officers/chief financial officers (CEOs/CFOs) of hospitals and health system practice plans, surgery department chairs, and surgery department members-from 12 randomly selected academic surgery departments. Important issues and solutions were identified and comparisons among stakeholder groups performed.

Carotid endarterectomy prior to ventricular assist device placement.

While there has been considerable debate regarding the timing of carotid endarterectomy (CEA) with respect to coronary artery bypass grafting, the ventricular assist device (VAD) patient population presents possible new concerns, given the implications of stroke while on mechanical support as a bridge to transplant. We present the first report in the literature of CEA in a patient with severe carotid disease prior to elective VAD placement.

The Coronary Artery Revascularization Prophylaxis (CARP) Trial: results and remaining controversies.

A high percentage of patients requiring elective vascular surgery also has indications for coronary artery revascularization, leading to varied opinions as to whether to undertake coronary artery revascularization first, to use risk stratification, or to do no coronary intervention before elective vascular surgery. The Coronary Artery Revascularization Prophylaxis (CARP) Trial determined the long-term benefit of coronary artery revascularization in patients with stable coronary artery disease undergoing elective infra-renal aortic or infra-inguinal vascular surgery. Following application of inclusion/exclusion criteria, those patients who did not require urgent vascular surgery or have significant co-existing conditions underwent cardiac evaluation and angiography.

Postoperative outcomes for patients undergoing elective revascularization for critical limb ischemia and intermittent claudication: a subanalysis of the Coronary Artery Revascularization Prophylaxis (CARP) trial.

Objective: To determine the perioperative mortality, myocardial infarction rate, and long-term survival of patients with critical limb ischemia (CLI) compared with those with intermittent claudication (IC) within a cohort selected for significant coronary artery disease, a secondary analysis was conducted of a prospective, randomized, multicenter trial of Coronary Artery Revascularization Prophylaxis (CARP) before peripheral vascular surgery. This multicenter trial was sponsored by the Cooperative Studies Program of the Department of Veterans Affairs.

Methods: Of the 510 patients enrolled in the CARP trial and randomized to coronary revascularization or no revascularization before elective vascular surgery, 143 had CLI and 164 had IC as an indication for lower limb revascularization; >95% of each group were men.

Moderate hyperoxia (40%) increases antioxidant levels in mouse tissue.

Background: Oxygen is routinely administered to patients to improve clinical outcome. Since studies have shown that administering 100% oxygen can cause unwanted side effects, intermediate concentrations of 40% oxygen are used in clinical practice. In this study, we examined whether the breathing of 40% oxygen causes beneficial effects upon tissue levels of antioxidants such as vitamin E, vitamin C, and glutathione.

Fate of the ectatic infrarenal aorta: expansion rates and outcomes.

The natural history of the ectatic infrarenal aorta remains undetermined. While surveillance protocols have been proposed for true aneurysms, no recommendations are currently available for ectatic aortas. The purpose of this study is to define the natural history and recommend surveillance protocols for the infrarenal aorta 2.

Use of a non-contact radiant heat bandage on ischemic dermal infections in an ovine model.

Background: Chronic non-healing foot wounds are common complication in the diabetic population. Local radiant heat bandage has recently been proposed as an effective adjuvant. The purpose of this study was to evaluate the efficacy of such bandage in controlling infection in an ovine ischemic wound model.

Supplemental oxygen reduces intimal hyperplasia after intraarterial stenting in the rabbit.

Hypothesis: Supplemental oxygen can reduce intimal hyperplasia (IH) after stent deployment in a rabbit model.

Background: Endovascular stent placement is technically feasible, but long-term durability in vessels outside the aortoiliac system is compromised with postinterventional IH, which causes restenosis and failure of the arterial conduit.

Methods: Groups (n = 4 to 6) of female New Zealand white rabbits underwent placement of a 3-mm intraaortic stent with laparotomy and were placed in either normoxic (21% inspired oxygen concentration) or supplemental-oxygen (40% inspired oxygen concentration) environments for 0, 7, 14, and 28 days.

Expansion rates and outcomes for the 3.0-cm to the 3.9-cm infrarenal abdominal aortic aneurysm.

Objective: This study was performed for the determination of the expansion rates and outcomes and for recommendations for the surveillance of the 3.0-cm to 3.9-cm abdominal aortic aneurysm (AAA).