Robyn A. Macsata

The Society for Vascular Surgery: Clinical practice guidelines for the surgical placement and maintenance of arteriovenous hemodialysis access

Recognizing the impact of the decision making by the dialysis access surgeon on the successful placement of autogenous arteriovenous hemodialysis access, the Society for Vascular Surgery assembled a multispecialty panel to develop practice guidelines in arteriovenous access placement and maintenance with the aim of maximizing the percentage and functionality of autogenous arteriovenous accesses that are placed. The Society commissioned the Knowledge and Encounter Research Unit of the Mayo Clinic College of Medicine, Rochester, Minnesota, to systematically review the available evidence in three main areas provided by the panel: timing of referral to access surgeons, type of access placed, and effectiveness of surveillance. The panel then formulated practice guidelines in seven areas: timing of referral to the access surgeon, operative strategies to maximize the placement of autogenous arteriovenous accesses, first choice for the autogenous access, choice of arteriovenous access when a patient is not a suitable candidate for a forearm autogenous access, the role of monitoring and surveillance in arteriovenous access management, conversion of a prosthetic arteriovenous access to a secondary autogenous arteriovenous access, and management of the nonfunctional or failed arteriovenous access. For each of the guidelines, the panel stated the recommendation or suggestion, discussed the evidence or opinion upon which the recommendation or suggestion was made, detailed the values and preferences that influenced the groups decision in formulating the relevant guideline, and discussed technical remarks related to the particular guideline. In addition, detailed information is provided on various configurations of autogenous and prosthetic accesses and technical tips related to their placement.

Transforming growth factor-beta and wound healing.

Acute and chronic wounds are a source of significant morbidity for patients, and they demand a growing portion of health-care time and finances to be devoted to their care. Transforming growth factor-beta (TGF-beta) has surfaced from abundant research as a key signal in orchestrating wound repair. In beginning this review, we discuss the inflammatory, proliferative, and maturational phases of wound healing. We then focus on TGF-beta by first discussing the pathway from its production to the target cell where Smad proteins execute an intracellular signaling cascade. To review TGF-betas role in wound healing, we discuss the actions of it individually on keratinocytes, fibroblasts, endothelial cells, and monocytes, which are the major cell types involved in wound repair. From illustrating these cellular actions of TGF-beta, we summarize its multipotent role in the process of wound repair. As a clinical correlation, we also review research dedicated to the involvement of TGF-beta in venous stasis ulcers.

Transforming Growth Factor-β and Wound Healing

Acute and chronic wounds are a source of significant morbidity for patients, and they demand a growing portion of health-care time and finances to be devoted to their care. Transforming growth factor-beta (TGF-beta) has surfaced from abundant research as a key signal in orchestrating wound repair. In beginning this review, we discuss the inflammatory, proliferative, and maturational phases of wound healing. We then focus on TGF-beta by first discussing the pathway from its production to the target cell where Smad proteins execute an intracellular signaling cascade. To review TGF-betas role in wound healing, we discuss the actions of it individually on keratinocytes, fibroblasts, endothelial cells, and monocytes, which are the major cell types involved in wound repair. From illustrating these cellular actions of TGF-beta, we summarize its multipotent role in the process of wound repair. As a clinical correlation, we also review research dedicated to the involvement of TGF-beta in venous stasis ulcers.

Impact of Obesity on Outcomes after Open Surgical and Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND This study examined impact of obesity on outcomes after abdominal aortic aneurysm repair. STUDY DESIGN Data were obtained from the Veterans Affairs National Surgical Quality Improvement Program. Body mass index (BMI) was categorized according to National Institutes of Health guidelines. Multivariate regression adjusted for 40 other risk factors to analyze trends in complications and death within 30 days. RESULTS We identified 2,201 patients undergoing 1,185 open and 1,016 endovascular aneurysm repairs (EVAR) for abdominal aortic aneurysms from January 2004 through December 2005. BMI distribution was identical in both groups and reflected national population statistics: approximately 30% were normal (BMI 18.5 to 24.9), 40% were overweight (25.0 to 29.9), and 30% were obese class I (30.0 to 34.9), II (35.0 to 39.9), or III (>/=40.0). After open repair, obesity of any class was independently predictive of wound complications (adjusted odds ratio = 2.4; 95% CI, 1.5 to 5.3; p = 0.002). Class III obesity was also an independent predictor or renal complications (adjusted odds rato = 6.3; 95% CI, 2.2 to 18.0; p < 0.0001) and cardiac complications (adjusted odds ratio = 4.5; 95% CI, 1.1 to 22.9; p = 0.045. After EVAR, obesity (any class) was predictive of wound complications (adjusted odds ratio = 3.1; 95% CI, 1.1 to 8.1; p = 0.026), but not predictive of other complications or death. Between the two types of operation, there were fewer complications and deaths after EVAR compared with open repair across all BMI categories, but outcomes were most disparate among the obese. CONCLUSIONS Obesity is an independent risk factor that surgeons should consider during patient selection and operative planning for abdominal aortic aneurysm repair. Obese patients appear to particularly benefit from successful EVAR over open repair, but if open repair is required, special attention should be paid to cardiac risk, perioperative renal protection, and aggresive wound infection prevention measures.

Reoperation rates after open and endovascular abdominal aortic aneurysm repairs

Objective: This study compared reoperation rates associated with open abdominal aortic aneurysm (AAA) repair (OR) outcomes vs endovascular AAA repair (EVAR). Methods: A retrospective review of the Veterans Affairs Surgical Quality Improvement Project data was performed with inclusion criteria defined as all patients who underwent AAA repair from October 1, 2007, to October 1, 2013. The primary outcome was the incidence of reoperations. Reoperations included subsequent OR or EVAR procedures performed on the abdominal aorta or iliac arteries, surgical treatment of temporally related bowel obstruction, as well as treatment of abdominal or groin wound complications ≤6 months and treatment of bowel or lower limb ischemia ≤10 days. Results: Of 6677 patients who underwent AAA repair, 476 (7.1%) required reoperations. OR was associated with a higher rate of reoperations overall (10.0% vs 6.3%; P < .01), with most being intra‐abdominal and wound complications. OR also had higher rates of bowel ischemia requiring operation (0.7% vs 0.3%; P = .01) and lower extremity ischemia (0.5% and 0.06%; P < .01). Significantly more endovascular stents were placed during EVAR (2.8% vs 0.5%; P < .01). Logistic regression showed EVAR is a negative predictor for reoperation after controlling for comorbidities (P < .001). Conclusions: The long‐term burden of reoperations after OR may actually be more significant than current understanding when including all possible abdominal complications in an extended analysis. Future prospective trials should include all potential reoperations extended >30 days with associated cost analysis. As surgical innovation in EVAR technology advances, complication comparisons with OR should undergo frequent re‐evaluation given that endovascular indications and outcomes continue to expand and improve.

Functional status as a predictor of outcomes in open and endovascular abdominal aortic aneurysm repair

Background: Functional status is a simple and rapidly assessable metric that may be used as a predictor for surgical outcomes. This study examined the association of functional status with short‐term mortality after abdominal aortic aneurysm (AAA) repair in octogenarians to characterize the utility of functional status as a means of preoperative risk assessment. Methods: All patients who underwent endovascular and open AAA repair from 2002 to 2010 within the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database were identified. Functional status, defined as an ordinal scale from 1 to 3 (1, independent; 2, partially dependent; 3, totally dependent), was examined using multivariate regression models with 30‐day mortality as the primary outcome. For the purpose of analysis, this 3‐point scale was converted into a binomial scale of function, with “normal” including 1 (completely independent) and “abnormal” including 2 or 3 (partially to totally dependent). Results: We identified 9030 patients who underwent AAA repair (46.6% open and 53.4% endovascular). Mortality at 30 days was 2.8% for the entire cohort (4.2% open, 1.7% endovascular; P < .001). There were 1340 patients aged ≥80 years, of which 67.3% underwent endovascular AAA repair. Among all age groups, functional status was a significant predictor of 30‐day mortality (<80 years, P < .001; ≥80 years, P < .001). The ≥80 cohort with abnormal function status also demonstrated increased operative mortality (P = .002), length of stay (P = .001), and incidence of pulmonary complications (P = .025) compared with the cohort with normal functional status. Multivariate logistic regression demonstrated that within the ≥80‐year‐old cohort, only functional status remained a significant predictor of mortality (P < .001). In addition, the strength of the association between functional status and mortality was greater in the older cohort than in the younger one (Cox regression hazard ratio: 3.13 vs 2.18). Conclusions: Functional status is a simple and rapidly applicable predictor of mortality within AAA patients and may be a useful tool to help preoperatively risk‐stratify elderly patients presenting with AAA in need of repair. Further studies are needed to understand how best to apply these data to the clinical setting to guide preoperative decision making.

Vascular Laboratory Protocol and Ultrasound Mapping Techniques for Dialysis Access Planning

The successful placement of a dialysis access which is of utmost importance for patients with end-stage renal disease can be optimized by a pre-procedural evaluation that includes duplex ultrasound. Imaging of upper extremity superficial and deep veins for patency and caliber increases the frequency of autogenous dialysis access placement. Duplex arterial imaging and indirect physiologic testing should document normal arterial flow and provide information on the presence of radial artery wall calcification. The goal of duplex ultrasound testing is to provide the dialysis access surgeons with anatomic and physiologic information to construct a high-flow dialysis access and maximize the number of primary autogenous fistula performed. In this chapter, the preoperative work-up for dialysis access planning is detailed, including vein mapping of the superficial and deep veins and the arterial duplex imaging protocol.

Arteriovenous Grafts: Stenosis, Thrombosis and Aneurysms

The arterial supply of the upper extremity begins at the aortic arch; the right subclavian artery originates from the innominate (brachiocephalic) artery, while the left subclavian artery originates directly from the aortic arch. After crossing the first rib, the subclavian becomes the axillary artery; after crossing the lower border of the teres major, it becomes the brachial artery. In the antecubital fossa, the brachial artery bifurcates into the radial and ulnar arteries. The radial artery courses laterally in the forearm and then posterior at the wrist to the anatomical snuffbox where it forms the major branches of the deep palmar arch and communicates with the deep branches of the ulnar artery. The ulnar artery courses medially in the forearm to the wrist, where it forms the major branches of the superficial palmar arch and communicates with the superficial branches of the radial artery.

Protocol and Mapping Techniques Prior to Hemodialysis Access Planning

Successful hemodialysis access placement is of utmost importance for patients with chronic kidney disease and end-stage renal disease, and it is optimized by preoperative evaluation and planning. This evaluation includes history and physical examination by the surgeon as well as noninvasive imaging. In this chapter, we discuss the preoperative workup for hemodialysis access including vein mapping of the superficial and deep venous systems of the upper extremity as well as segmental pressures, pulse-volume recording, and arterial duplex imaging. Each test is used preoperatively with the goal of improving outcomes for hemodialysis access placement.