Preoperative Venous Mapping Research Articles

Small Caliber Distal Cephalic Veins Undergo Significant Dilation under Anesthesia and Can Successfully Be Used for Arteriovenous Fistula Creation

Successful arteriovenous fistula (AVF) maturation and use for dialysis is highly dependent on preoperative diameter. Small veins (<2mm) exhibit high failure rates and are typically avoided. This study investigates the effects of anesthesia on the distal cephalic vein diameter as compared to preoperative outpatient vein mapping for the purpose of hemodialysis access creation. One hundred eight consecutive procedures for dialysis access placement met inclusion criteria and were reviewed. All patients received preoperative venous mapping and postanesthesia ultrasound mapping (PAUS). All patients received either regional and/or general anesthesia. A multiple regression was conducted to determine predictors of venous dilatation. The independent variables included both demographical and operative-specific variables such as the type of anesthesia. Outcomes of fistula maturation (successful cannulation and dialysis) were analyzed. In this cohort, the mean preoperative vein diameter was 1.85mm and the mean PAUS diameter was 3.45mm, a 2.21× increase, with only 2 patient veins failing to increase in diameter. Smaller veins (<2mm) exhibited significantly more dilation than larger veins after anesthesia (2.73 vs. 1.47×, P<0.001). In the multiple regression analysis, smaller vein diameter was correlated with a significantly greater degree of dilation (P<0.001). The degree of venous dilation was not affected by patient demographic-specific factors or by the type of anesthesia (regional block versus general) in the multiple regression analysis. 6month follow-up data for fistula maturation was available for 75 of 108 patients. Small veins (<2mm) on preoperative ultrasound matured at a similar rate as larger veins (90% vs. 91.4%, P=0.833). Small caliber distal cephalic veins experience a significant degree of dilation under regional and general anesthesia and can successfully be used for AVF creation. Consideration should be made to perform a postanesthesia vein mapping for all patients undergoing access placement despite preoperative venous mapping results.

The impact of pre-existing venous pathology on lower limb free flap reconstruction and the role of preoperative screening: a systematic review.

Lower limb reconstruction is performed to replace like with like and achieve tissue durability. Free flaps are a method of reconstruction commonly used to manage cases of lower limb deficits. However, the failure rate is 8.5%, with venous thrombosis and congestion playing a significant role. Despite this, preoperative venous mapping of recipient site before free flap reconstruction is not routinely practiced, often resulting in pathologies remaining unidentified until the intraoperative stage. The aim of the review was to evaluate the existing literature on the topic of lower limb preoperative venous assessment, screening, and its effect on lower limb free flap survival. Five different databases were searched from their inception to August 2021. The search terms and included studies were independently reviewed by two investigators for their eligibility. Eleven articles were eligible for inclusion, with a combined patient population of 99, and 107 flaps were identified to have lower limb pathology at the donor or recipient vein. Venous pathology was detected preoperatively in 69 veins using ultrasound duplex scanning and computed tomography angiography; of them, 3 (4.34%) resulted in failure. In comparison, 38 veins were diagnosed with venous pathology intraoperatively; of them, 5 (13.85%) failed. The studies evaluated in this review demonstrated that preoperative screening for venous pathology showed a higher flap survival rate. It can therefore be inferred that developing a standardized preoperative process for identifying venous issues in lower limb free flap reconstruction may improve outcomes. This can be explored in future research, with a focus on assessing the validity and efficacy of such screening tools, and their role in the management of patients identified with venous pathology.

Reliability of preoperative venous mapping ultrasonography in predicting for autogenous arteriovenous fistula maturation

BackgroundAutogenous arteriovenous fistula creation is the preferred route for vascular access for hemodialysis. Although preoperative venous mapping ultrasonography has been advocated as an operative planning adjunct and recently incorporated into the Society for Vascular Surgery clinical guidelines, controversy remains regarding its usefulness for predicting access success. The purpose of the present retrospective clinical study was to test the hypothesis that vein size measured on routine preoperative venous mapping is a poor predictor of primary fistula maturation. MethodsConsecutive upper extremity autogenous arteriovenous fistulas created by three dedicated vascular surgeons were retrospectively reviewed. The demographic characteristics, preoperative venous mapping, functional maturation, and patency were analyzed. The clinically relevant variables were tested for predictive significance using a logistic regression model. ResultsA total of 199 upper extremity autogenous arteriovenous fistulas had been created during a 5-year period. Patients were aged 70 ± 16 years (range, 20-96 years), and 62% were men. Most had already been undergoing dialysis before fistula creation (83%), usually via a tunneled central venous catheter (62%). Radial-cephalic, brachial-cephalic, and brachial-basilic arteriovenous fistulas had been created in 82 patients (41%), 76 patients (38%), and 10 patients (5%), respectively. Fistula maturation, defined as a palpable thrill and/or successful cannulation of the fistula with the ability to deliver a flow rate of 400 mL/min, was achieved in 67% of the patients. A higher body mass index was associated with nonmaturation on both univariate and multivariate analyses (success, 28.6 ± 7.7 kg/m2; vs failed, 31.6 ± 9.4 kg/m2; P = .029; odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02-1.10; P < .01). On univariate analysis, the maximum target vein diameter assessed by preoperative venous mapping was slightly larger in the group achieving successful maturation (2.9 ± 1.1 mm vs 2.6 ± 0.9 mm; P = .014). However, neither the maximum target vein diameter nor a target vein size >3 mm was significantly predictive of maturation on multivariate analysis (maximum vein diameter: OR, 0.65; 95% CI, 0.35-1.22; P = .176; vein size >3 mm: OR, 0.91; 95% CI, 0.32-2.60; P = .857). After a median follow-up of 15 months (interquartile range, 26 months), the primary functional patency, primary-assisted patency, and secondary patency rates were 39.1% ± 0.6%, 94.5% ± 0.6%, and 97.9% ± 0.5%. No association of vein diameter with long-term patency was found. ConclusionsDespite the national fistula-first initiatives, most patients still undergo access via catheter at the initiation of hemodialysis. The use of routine preoperative venous mapping does not predict successful primary maturation. Also, no clinically useful predictor of fistula maturation was identified in the present study.

Non-Invasive Imaging of Preoperative Mapping of Superficial Veins in Free Flap Breast Reconstruction.

Non-Invasive Imaging of Preoperative Mapping of Superficial Veins in Free Flap Breast Reconstruction.

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

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. 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 >2mm and >2.5mm size criteria respectively (group A) or vein size or length were suboptimal (2-2.5mm and<5cm 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. 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. 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.

Intraoperative Evaluation Is Superior to Preoperative Venous Mapping in Predicting Arteriovenous Fistula Success

Intraoperative Evaluation Is Superior to Preoperative Venous Mapping in Predicting Arteriovenous Fistula Success

Impact of pre-operative venography on the planning and outcome of vascular access for hemodialysis patients

Pre-operative venous mapping has increased dramatically in most dialysis units since the Dialysis Outcome Quality Initiative (DOQI) guidelines recommended a native arteriovenous venous fistula (AVF) rather than a graft for hemodialysis (HD) access procedures. However, there are conflicting consequences as a result of this policy. Some studies have showed that routine mapping has resulted in a marked increase in maturation rate while others have observed the reverse. This study aimed to evaluate the impact of pre-operative venography on the planning and outcome of AVF for our HD patients. A prospective study was performed on all patients with end-stage renal disease (ESRD) who had HD access procedures and pre-operative venography between October 2003 and November 2005. Upper limb venography was done for all patients except those that required primary access and had visible veins. All patients had HD immediately after the venography. Access procedure selection was based on the result of the venography. The complications of venography, the surgical procedure and the outcome were recorded. One hundred and twenty-nine patients with ESRD who had pre-operative venography were included in this study. They were mostly middle age (mean age +/- SD = 41 +/- 15.5 yrs) with a high rate of diabetes mellitus (53%). No single complication was reported. A graft was placed in six patients (5%) only. Unsuccessful surgical exploration was 0%. Early failure was in 10 patients (8%). Pre-operative venography resulted in an increase in the number of AVFs. It can improve the results of HD access procedures by selecting the most suitable veins.

Selected indications for and applications of magnetic resonance angiography in children.

The purpose of this study was to investigate the efficacy and practicality of magnetic resonance angiography (MRA) in evaluating pediatric cerebrovascular disorders. A retrospective evaluation was performed of MR angiograms in 20 pediatric patients with cerebrovascular pathology. When appropriate, comparisons were made with duplex ultrasonography or conventional catheter angiography. MRA accurately assessed the patency of carotid reanastomoses in 8 babies who had previously undergone extracorporeal membrane oxygenation (ECMO). In 6 patients with moyamoya syndrome, MRA accurately evaluated stenotic intracranial carotid and circle of Willis arteries and progressive enlargement of the superficial temporal and middle cerebral arteries after revascularization procedures, and thus obviated the need for sequential angiograms. Thrombi and emboli were identified in 4 of 5 patients with symptoms and imaging evidence of an acute stroke. Two-dimensional time-of-flight MR venograms, acquired in both axial and coronal planes, were useful for preoperative venous mapping in a patient with an occipital encephalocele and detecting venoocclusive disease. MRA provided diagnostically useful information in a spectrum of pediatric cerebrovascular disorders. It can be used as the initial vascular imaging modality for patients with imaging evidence of acute cerebrovascular event, to evaluate progression of chronic vasoocclusive disease, to evaluate vessel patency following intracranial revascularization surgery, and for visualization of the venous circulation.