The correlation of early flow disturbances with the development of infrainguinal graft stenosis: A 10-year study of 341 autogenous vein grafts

AbstractPurpose: Although duplex surveillance of infrainguinal bypass grafts is widely accepted, the optimal frequency and intensity of graft surveillance remains controversial. Earlier reports have suggested that grafts can be stratified into high-risk and low-risk groups based on the presence or absence of early graft flow disturbances. The purpose of this study was to provide long-term data in determining whether early graft flow disturbances detected by means of duplex scanning can predict the development of intrinsic vein graft stenosis. Methods: We reviewed a series of patients undergoing prospective duplex graft surveillance after autogenous infrainguinal bypass grafting procedures from 1987 to 1997. Patients included in the study underwent at least one duplex scan within 3 months of graft implantation and were observed for a minimum of 6 months. Grafts were categorized as abnormal when a focal flow disturbance with a peak systolic velocity greater than 150 cm/s was identified within 3 months of graft implantation. Results: Of 341 vein grafts in 296 patients who met inclusion criteria, 89 grafts (26%) required revision for intrinsic stenosis; the mean follow-up period was 35 months (range, 6 months to 10 years). Early flow disturbances were detected in 84 (25%) grafts. Grafts with early flow disturbances were more likely to ultimately require revision (43% vs 21%; P = .0001) and required initial revision earlier (8 months vs 16 months; P = .019). Eighty-two percent of initial graft revisions occurred in the first 2 postoperative years; 69% occurred in the first year. However, an annual 2% to 4% incidence of late-appearing graft stenosis persisted during long-term follow-up. An additional 24 patients (7% of grafts) required an inflow or outflow reconstruction. Conclusion: Grafts with early postoperative flow disturbances detected by means of duplex scanning have nearly three times the incidence of graft-threatening stenosis and an earlier requirement for revision, when compared with normal grafts. This suggests that the biology and etiology of these lesions may differ. These data support not only aggressive efforts to detect early graft lesions to stratify grafts at highest risk, but also continued lifelong graft surveillance to detect late-appearing lesions, inflow and outflow disease progression, and maximize graft patency. (J Vasc Surg 1999;30:8-15.

How to Detect X-Rays and Gamma-Rays from Space: Optics and Detectors

The measurable quantities of the sky’s light, for any wavelength, are energy, position, arrival time, and polarization. Each of them reveal different information about the science target (e.g. gas dynamics, state and distribution of the matter, temperature, luminosity) and require specific detecting solutions. In the study of X-rays and gamma-rays up to the TeV regime, their absorption by the atmosphere (by 50% at 30 km altitude for 1 MeV photon) requires the development of space applications. The science goals of the mission define which technological benchmark should be maximised (e.g. energy or spatial resolution), but the final design of high energy instruments is the result of a trade-off analysis among the detection specifications, the need for space-borne electronic systems and materials, and the limited resources in mass budget, electrical power, and telemetry rates

Venous reconstructions using the superficial femoral–popliteal vein

AbstractPurpose: To demonstrate the feasibility of venous reconstructions with the superficial femoral–popliteal vein (SFPV).Methods: Seven patients who underwent a variety of major venous reconstructions using SFPV were reviewed in a retrospective, observational study.Results: Three central venous reconstructions (thoracic and abdominal) and four peripheral major venous reconstructions were performed with SFPV autografts. In all patients, the SFPV grafts provided an excellent size match and were of adequate length without the need for enlargement by paneling or spiraling techniques. Postoperative anticoagulation medication was not used. There were no early graft failures, and patency was documented by duplex ultrasound, venogram, or both in all patients at a mean of 20 months follow-up. Venous thromboembolism has not occurred, and lower extremity venous morbidity has been minimal.Conclusions: The SFPV graft demonstrates versatility and durability in selected patients who require large-caliber conduits for venous reconstruction. Because of its size and availability, the SFPV is an excellent conduit for major venous reconstruction. (J Vasc Surg 1997;26:829-37.

Surgical Management of Diabetic Foot Infections and Amputations.

The incidence of diabetes with severe foot infections (eg, necrotizing fasciitis, gas gangrene, ascending cellulitis, infection with systemic toxicity or metabolic instability) has risen significantly during the past decade. Foot infections are a major cause of hospitalization and subsequent lower extremity amputation among patients with diabetes mellitus who have a history of a preexisting ulceration. Surgical management often is required to address severe diabetic foot infections because they can be limb- or life-threatening. Critical limb ischemia, neuropathy, and an immunocompromised host, which often are associated with diabetic foot infections, complicate treatment and are associated with a poorer prognosis