Reliability and accuracy of duplex ultrasound vein mapping for dialysis access.

BACKGROUND: Duplex ultrasound vein mapping (DUVM) may increase autogenous dialysis access procedures but has not been universally adopted by surgeons. METHODS: We determined reliability and accuracy of arm vein measurements on physical examination (PE) and DUVM, compared to direct measurements in the operating room (OR, gold standard). Operative plans were developed from each set of measurements and we evaluated which approach identified more options for autogenous procedures. RESULTS: Vein diameters measured on DUVM correlated well with OR measurements but those made on PE did not. Autogenous access options were identified in 34.8% of patients based on PE and in 96.6% based on their DUVM. The 6-month primary-patency was 86.4%; assisted primary-patency was 89.8%. CONCLUSIONS: Duplex ultrasound vein mapping is more reliable and accurate for assessing arm vein anatomy than physical examination. It identifies more autogenous options than physical-examination alone. It is essential for the preoperative evaluation for dialysis access.

Modalities to Treat Venous Ulcers: Compression, Surgery, and Bioengineered Tissue.

BACKGROUND: Venous leg ulcers (VLUs) represent the most common ulcers of the lower extremity. VLUs are notorious for delayed and prolonged healing with high rates of recurrence. Most patients with VLUs also have significant comorbidities that interfere with primary wound healing. Thus, caring for patients with VLUs requires an interdisciplinary approach that addresses the abnormal venous anatomy and the downstream effects that lead to inflammation, ulceration, and a hostile wound microenvironment. METHODS: The current literature regarding venous ulcer treatment with an emphasis on compression, surgical options, and use of bioengineered tissue was reviewed. A combination of society guidelines, Cochrane reviews, and over 80 primary articles with high-level evidence were utilized to develop this summary and algorithm for an integrated approach to treating patients with venous ulcers. Details regarding compression modalities and venous diagnostic imaging are presented to help the clinician understand the rationale for using these technologies. RESULTS: The comprehensive approach to the patient with chronic venous insufficiency (CVI) includes advances in compression, diagnostics, minimally invasive surgical treatment of venous disease, wound bed preparation, and bioengineered skin and soft tissue substitutes. An algorithm that incorporates early treatment of the ulcer and the venous disease leading to healing with prevention of recurrence is presented. CONCLUSIONS: Utilizing guidelines that incorporate evidence-based modalities will lead to the highest quality outcomes with the most appropriate resource utilization. A proactive approach to treating venous disease will alleviate suffering and prevent the long-term sequelae of CVI.

Cellular basis of burn-induced cardiac dysfunction and prevention by mesenteric lymph duct ligation.

BACKGROUND: Myocardial contractile depression develops 4 to 24 h after major burn injury. We have reported previously that in a rat burn injury model (≈40% of total body surface area burn), mesenteric lymph duct ligation (LDL) prior to burn prevented myocardial dysfunction. However, the underlying cellular and molecular mechanisms are not well understood. MATERIALS AND METHODS: Left ventricular myocytes were isolated from sham burn (control), sham burn with LDL (sham + LDL), burn, and burn with LDL (burn + LDL) rats at 4 and 24 h after burn or sham burn. Electrophysiological techniques were used to study myocyte size, contractility and L-type Ca2+ channel current (ICa). Further studies examined changes in the messenger RNA expression levels of pore-forming subunit of the L-type Ca(2+) channel, α1C, and its auxiliary subunits, ß1, ß2, ß3, and α2δ1, which modulate the abundance of the ICa in post-burn hearts. RESULTS: Depressed myocyte contractility (≈20%) developed during 4 to 24 h post-burn compared with control, sham + LDL, or burn + LDL groups, a pattern of changes consistent with whole heart studies. There was no significant alteration in myocyte size. The ICa density was significantly decreased (≈30%) at 24 h post-burn, whereas the messenger RNA expression levels of Ca(2+) channel gene were not significantly altered at 4 and 24 h after burn injury. CONCLUSIONS: These results suggest that the post-burn contractile phenotype in vivo was also present in isolated myocytes in vitro, but cellular remodeling was not a major factor. The results also suggest that changes in ICa regulation, but not from Ca(2+) channel gene modification, may be a key element involved in post-burn contractile depression and the beneficial effects of LDL.

Mesenteric lymph from rats with trauma-hemorrhagic shock causes abnormal cardiac myocyte function and induces myocardial contractile dysfunction.

Myocardial contractile dysfunction develops following trauma-hemorrhagic shock (T/HS). We have previously shown that, in a rat fixed pressure model of T/HS (mean arterial pressure of 30-35 mmHg for 90 min), mesenteric lymph duct ligation before T/HS prevented T/HS-induced myocardial contractile depression. To determine whether T/HS lymph directly alters myocardial contractility, we examined the functional effects of physiologically relevant concentrations of mesenteric lymph collected from rats undergoing trauma-sham shock (T/SS) or T/HS on both isolated cardiac myocytes and Langendorff-perfused whole hearts. Acute application of T/HS lymph (0.1-2%), but not T/SS lymph, induced dual inotropic effects on myocytes with an immediate increase in the amplitude of cell shortening (1.4 ± 0.1-fold) followed by a complete block of contraction. Similarly, T/HS lymph caused dual, positive and negative effects on cellular Ca²âº transients. These effects were associated with changes in the electrophysiological properties of cardiac myocytes; T/HS lymph initially prolonged the action potential duration (action potential duration at 90% repolarization, 3.3 ± 0.4-fold), and this was followed by a decrease in the plateau potential and membrane depolarization. Furthermore, intravenous infusion of T/HS lymph, but not T/SS lymph, caused myocardial contractile dysfunction at 24 h after injection, which mimicked actual T/HS-induced changes; left ventricular developed pressure (LVDP) and the maximal rate of LVDP rise and fall (±dP/dt(max)) were decreased and inotropic response to Ca²âº was blunted. However, the contractile responsiveness to ß-adrenergic receptor stimulation in the T/HS lymph-infused hearts remained unchanged. These results suggest that T/HS lymph directly causes negative inotropic effects on the myocardium and that T/HS lymph-induced changes in myocyte function are likely to contribute to the development of T/HS-induced myocardial dysfunction.