Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery.

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

A doença renal crônica é um problema de saúde pública global e em seu estágio terminal está associada à necessidade de terapia dialítica. A grande maioria dos pacientes que necessitam realizar a terapia renal substitutiva, a fazem através da hemodiálise. Portanto, o acesso vascular é de extrema importância para a população dialítica, implicando diretamente na qualidade de vida e na morbimortalidade deste grupo de pacientes. Sendo a confecção, gerenciamento e resgate dos acessos vasculares uma das áreas de atuação do cirurgião vascular, é de grande importância a elaboração de uma diretriz que oriente o especialista no manejo mais adequado do acesso vascular para hemodiálise. Assim, o objetivo desta diretriz é apresentar um conjunto de recomendações para guiar as decisões na referenciação, avaliação, escolha, vigilância e gestão das complicações do acesso vascular para hemodiálise.

Accuracy of the pedal acceleration time to diagnose limb ischemia in patients with and without diabetes using the WIfI classification.

INTRODUCTION: Evaluation of limb hemodynamics using the ankle-brachial index (ABI) may be difficult due to skin lesions, extensive necrosis, and obesity, such as commonly present in patients with diabetes with chronic limb-threatening ischemia (CLTI). We hypothesized that the pedal acceleration time (PAT) correlates with ABI and Wound, Ischemia, and foot Infection (WIfI) scores in patients with diabetes to serve as a new modality to accurately stage CLTI. METHODS: A single-center, cross-sectional study included patients with and without diabetes > 18 years with CLTI. Limbs were categorized in three grades of ischemia based on the ABI (ABI < 0.8, < 0.6, and < 0.4) and in two classes based on WIfI stages of amputation risk. Receiver operator characteristic (ROC) curves were used to determine PAT sensitivity, specificity, and accuracy to predict lower-limb ischemia. RESULTS: A total of 141 patients (67 nondiabetic and 74 diabetic) and 198 lower limbs (94 nondiabetic and 104 diabetic) met the inclusion criteria. In patients without diabetes, the accuracy of PAT for detecting an ABI < 0.8 was 85%; for detecting an ABI < 0.6 was 85%; and for detecting an ABI < 0.4 was 87%. In patients with diabetes, the accuracy of PAT in detecting an ABI < 0.8 was 91%; for detecting an ABI < 0.6 was 79%; and for detecting an ABI < 0.4 was 88%. In patients without diabetes, the accuracy for detecting WIfI stages of moderate and high amputation risk was 77% and for patients with diabetes was also 77%. CONCLUSIONS: PAT shows high correlation with the ABI as well as with the WIfI stages of amputation risk and the grades of ischemia, with high accuracy.

Bilateral foam polidocanol sclerotherapy of great saphenous veins and their tributaries in synchronous procedure.

BACKGROUND: Chronic venous insufficiency is a highly prevalent disease. Advanced cases have high morbidity. OBJECTIVES: To evaluate the risks and benefits of foam sclerotherapy in patients who underwent bilateral treatment of the great saphenous veins in a single procedure, in selected cases of advanced venous insufficiency. METHODS: We retrospectively reviewed 55 patients (110 limbs) with bilateral incompetence of the great saphenous veins who had undergone foam sclerotherapy treatment bilaterally, using a maximum dose of 20 ml of foam per patient and inelastic compression. RESULTS: In 81 (73.6%) of the 110 saphenous veins analyzed, occlusion was obtained in the first session. After a second session this figure rose to 106 (96.3%) and all 110 (100%) veins were occluded after three sessions. Bilateral occlusion of the great saphenous veins was achieved in 27 patients (50%) in one session, in 34 (62%) patients in two sessions, and in 55 (100%) patients in three sessions. At 42 days after sclerotherapy, there was complete ulcer healing in seven (63%) of the 11 patients with ulcers and partial healing in 3 (27%) of these patients. One patient (1.8%) had self-limited lipothymia and visual scotomas, 3 patients (5.45%) had skin spots, and 19 patients (34.5%) developed retained intravascular coagulum. CONCLUSIONS: Bilateral foam sclerotherapy in a synchronous procedure is an option to be considered for treatment of varicose veins of the lower limbs.

Intraoperative vascular Doppler ultrasound blood flow and peak systolic velocity predict early patency in hemodialysis arteriovenous fistula.

BACKGROUND: Chronic kidney disease is a major public health problem. Hemodialysis is the most common renal replacement therapy. Arteriovenous fistulas (AVF) are a possible access option, but early failure rates remain high. OBJECTIVES: to investigate the value of intraoperative vascular Doppler ultrasound for predicting early AVF patency. METHODS: Prospective observational study. Consecutive patients undergoing AVF were assessed with vascular Doppler ultrasonography intraoperatively and on days 1, 7, 30, and 60. Patients were divided into groups according to presence or absence of primary and secondary patency. Blood flow (BF) and peak systolic velocity (PSV) were compared. ROC curves were plotted and used to define the PSV and BF values that yielded greatest sensitivity (Sens) and specificity (Spec). RESULTS: 47 patients met the inclusion criteria and were analyzed. Higher intraoperative PSV and BF values were observed in patients who had primary and secondary patency than in patients with access failure. The values with greatest sensitivity and specificity for predicting 30-day primary patency were 106 cm/s for venous PSV (Sens: 75% and Spec: 71.4%) and 290.5 ml/min for arterial blood flow (Sens: 80.6% and Spec 85.7%). Values for 30-day secondary patency were 106 cm/s for arterial PSV (Sens: 72.7%, Spec: 100%) and 230 ml/min for venous blood flow (Sens: 86.4%, Spec100%). Values for 60-day primary patency were 106 cm/s for venous PSV (Sens: 74.4%, Spec: 62.5%) and 290.5 ml/min for arterial blood flow (Sens: 80%, Spec: 75%). CONCLUSIONS: Peak systolic velocity and blood flow measured using intraoperative vascular Doppler ultrasound can predict early patency of hemodialysis arteriovenous fistulas.

Brachial vein transposition: an alternative to hemodialysis arteriovenous graft.

BACKGROUND: There is currently a worldwide effort to increase the options for autogenous hemodialysis access. OBJECTIVES: To evaluate patency and complications of brachial vein transposition compared to other autogenous hemodialysis accesses. METHODS: A retrospective evaluation of 43 patients and 45 procedures. Patients who did not have adequate superficial veins according to duplex scanning were allocated to brachial vein transposition. The sample was thus divided in two groups, as follows: A: brachial vein transposition n=10 and B: other autogenous accesses n=35. RESULTS: There were no statistical differences between the two groups in terms of age diabetes, systemic arterial hypertension, dyslipidemias, arteriopathies, neoplasms, kidney disease stage, donor artery diameter, recipient vein diameter, systolic blood pressure in the operated limb, postoperative ischemia, hematoma, or infection. There were no statistical differences in terms of patency on day 7: A 80% vs. B 90% p=0.6, on day 30: A 80% vs. B 86% p=0.6, or on day 60: A 60% vs. B 80% p=0.22. There were statistical differences between the groups for number of previous fistulae A 1.0 ± 0.44 vs. B 0.6 ± 0.3 p = 0.04 and upper limb edema A: 20% x B 0% p = 0.04. A vein with diameter of less than 3 mm was associated with an increased risk of early occlusion (RR = 8 p = 0.0125). During the study period there were no procedures using grafts. CONCLUSIONS: Transposition of brachial vein is an alternative to arteriovenous graft.

Matrix metalloproteinase 2 activity decreases in human periodontal ligament fibroblast cultures submitted to simulated orthodontic force.

Orthodontic force compresses the periodontal ligament promoting the expression of pro-inflammatory mediators and matrix metalloproteinases responsible for tooth movement. The extent in time while periodontal cells are being treated and the increment in the amount of mechanical stress caused by the orthodontic force is thought to regulate the levels of metalloproteinases in the periodontal tissue. To study the possible regulation in the activity of metalloproteinases 2, 3, 7, 9, and 10 by simulated orthodontic force, human periodontal ligament fibroblast cultures were centrifuged (141 × g) for 30, 60, 90, and 120 min, simulating the orthodontic force. Cell viability, protein quantification, and activity of metalloproteinases by zymography were evaluated at 24, 48, and 72 h after centrifugation in both cell lysates and growth medium. The activity of the 72-kDa matrix metalloproteinase 2 was decreased at 24 h regardless of the duration of centrifugation and at 48 h in cells centrifuged for 30 min only. Decrease in the amount of total protein in lysates was seen at 48 and 72 h with no change in cell viability. The data seem to indicate that the amount of mechanical stress regulates the levels of secreted matrix metalloproteinase 2. In addition, the centrifugation as a model for simulated orthodontic force may be used as a simple and reliable method to study the role played by matrix metalloproteinases in periodontal ligament when submitted to mechanical force as occurring during tooth movement.