Effectiveness of a native vein arteriovenous fistula tracking system.

OBJECTIVE: This study aims to evaluate the effectiveness of a tracking program on the functional maturation rate of arteriovenous fistula (AVF). METHODS: Two major clinical outcomes (commencement of cannulation and functional maturation) of created AVFs were compared between two cohorts. (i) Cohort 1: historical cohort; (ii) Cohort 2: AVFs created after implementation of the tracking project. Multivariable Cox regression models were used to assess the association between cohort allocation and the two major clinical outcomes. RESULTS: Data of 114 and 141 patients were analyzed respectively from Cohorts 1 (historical data) and 2 (with AVF tracking). After adjustment of covariates in the multivariable analysis, the AVFs created in Cohort 2 were more likely to be cannulated earlier (adjusted HR: 2.82; 95% CI: 1.97-4.05; p < 0.001), compared to those in Cohort 1. Similarly, the AVFs of Cohort 2 patients had significantly higher probability of functional maturation (adjusted HR: 1.81; 95% CI: 1.31-2.48; p < 0.001) than fistulas in Cohort 1. Cannulation was commenced for half of the AVFs by 4.1 months post-creation in the historical cohort (Cohort 1), whereas in the post-tracking cohort, 50% of the AVFs were cannulated by 2.3 months after creation (p < 0.001). It took 5.5 and 4.3 months for 50% of the AVFs created in Cohort 1 and Cohort 2 patients to achieve catheter-free functional maturation, respectively (p = 0.06). CONCLUSION: An AVF tracking program with maturation target for the access surgeons, together with a standardized tracking, feedback, and clinical strategy adjustment system is able to improve the AVF functional maturation rate.

A percutaneous approach to create tricuspid regurgitation in swine: a model for transcatheter tricuspid valve therapy assessment.

PURPOSE: The purpose of this study was to develop a simple and effective percutaneous approach to create tricuspid regurgitation in swine. METHODS: Eleven pigs (71.68 ± 7.70 kg, 3 male) were involved in this study. A grasping forceps was introduced into the right ventricle through a steerable sheath under fluoroscopic guidance and used to disrupt the tricuspid valve apparatus by avulsing leaflet or chordae tendineae repeatedly. Transthoracic echocardiography and right ventricular angiography were used to evaluate the degree of tricuspid regurgitation created. RESULTS: Ten of the 11 pigs (90.91%) achieved severe tricuspid regurgitation and 1 (9.09%) obtained moderate tricuspid regurgitation immediately after the procedure. Heart rate of the pigs significantly increased immediately after tricuspid regurgitation creation compared to baseline (88.64 ± 23.24 vs. 76.00 ± 15.30 bpm, P = 0.02), but recovered to normal level at one month follow-up (77.09 ± 11.97 bpm, P = 0.85). The right atrium, tricuspid valve annulus, and right ventricle dilated obviously one month after tricuspid regurgitation creation (dimension changes: 3.01 ± 0.35 vs. 3.56 ± 0.40 cm, P = 0.02; 2.92 ± 0.36 vs. 3.37 ± 0.39 cm, P = 0.01; 3.06 ± 0.42 vs. 3.60 ± 0.47 cm, P = 0.03 respectively). Autopsy findings showed that rupture of leaflet and/or chordae tendineae finally led to the tricuspid regurgitation. CONCLUSIONS: Severe tricuspid regurgitation can be created by a simple and effective percutaneous approach with a grasping forceps in swine model and right heart dilation can be observed consistently at one-month follow-up. This model will be valuable in pre-clinical studies for developing new tricuspid valve repair or replacement technique to treat severe tricuspid regurgitation.

Effect of brachial plexus block-driven vascular access planning on primary distal arteriovenous fistula recruitment and outcomes.

OBJECTIVE: Hemodialysis vascular accesses (VAs) are traditionally planned based on the nondominant upper extremity preoperative physical and sonographic vascular findings. Clinical guidelines advocate the use of the most suitably distended vein in the most distal location. Brachial plexus block (BPB), through its sympathectomy-like effect, promotes vasodilation and can thus further optimize vein recruitment and operative strategy. However, studies on its role in driving primary distal autogenous arteriovenous fistula (AVF) placement are limited. We therefore evaluated a traditional approach of clinic-based VA planning against an on-table sonography-guided strategy under BPB. METHODS: This was a prospective observational study involving 110 consecutive end-stage renal disease multiethnic Asian patients referred for primary VA creation under BPB after preoperative venous mapping. Cases were grouped according to whether there was a preset operative plan for radial cephalic (RC) or brachial cephalic (BC) AVF creation based on artery and vein >2 mm and >2.5 mm size criteria respectively (group A) or vein size or length were suboptimal (2-2.5 mm and <5 cm respectively), thus precluding any operative plan till after BPB (group B). Group B also included cases with a preset VA plan but that subsequently underwent an on-table change in operative plan as a result of more favorable distal vein dilation post-BPB. RC AVF recruitment, maturation, and patency rates were compared in the two groups over a 1-year follow up. RESULTS: One hundred RC and BC AVF were available for analysis after excluding brachial AVFs and grafts: 41 in group A and 59 in group B. Twenty one (51%) primary RC AVFs were created according to a preset preoperative plan compared with 37 (63%) based upon on-table planning or plan modification (P > .05). Satisfactory post-BPB forearm vasodilation resulted in 44% of 36 plans for BC being changed to RC AVFs. RC AVF 6-week hemodynamic maturation and 3-month functional maturation in group A vs B were 48% vs 60% and 69% vs 57%, respectively (P > .05). One-year primary and secondary patency rates were 57% vs 50% and 73% vs 87%, respectively (log rank >.05). Outcomes of RC AVFs in group B were not inferior to those of BC AVFs. CONCLUSIONS: On-table BPB-driven VA planning and plan modification strategy contribute to considerable AVF recruitment but do not lead to significantly better distal AVF prevalence or outcomes over the traditional approach. An adequately powered randomized controlled study is, however, warranted to better assess the long-term clinical and cost benefits of such a strategy.

Pilot single-arm study to investigate the efficacy and safety of endovenous Microwave ablations for treatment of varicose veins in Singapore - one year results of the MAESTRO registry.

OBJECTIVES: Aim was to report a prospective two-centre Singaporean experience using Endovenous Microwave Ablation (EMA) to treat symptomatic primary great saphenous vein reflux. We evaluated 1-year safety, efficacy and patient satisfaction. METHODS: 50 patients (63 limbs; 29 females; mean age 58.0 ± 12.1 years) were included. Patients were reviewed at 2-weeks, 3-, 6- and 12-months and underwent Duplex ultrasound assessment. Three quality of life (QoL) questionnaires were completed. RESULTS: The truncal closure rates at 2-weeks, 3-, 6- and 12-months were 63/63 (100%), 59/59 (100%), 58/58 (100%) and 59/60 (98.3%), respectively. There was 100% technical success and no serious adverse events. There were sustained improvement of QoL questionnaire scores from 2 weeks to 12 months. CONCLUSION: EMA is a safe and efficacious venous ablative technology at 12 months and is associated with a high rate of target vein occlusion and sustained QoL improvement.