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.

Predicting late aortic complications after acute type A dissection surgery with volumetric measurements in a Singapore cohort

Introduction

This study was conducted to evaluate the efficacy of postoperative computed tomography (CT) measurements of aortic lumen volumes in predicting aortic-related complications following acute type A aortic dissection (ATAAD) repair.

Methods

We conducted a single-institution retrospective aortic volumetric analysis of patients after ascending aorta replacement performed during 2001-2015. The volumetric measurements of total lumen (total-L), true lumen (TL), false lumen (FL), as well as the TL:FL ratio from the first and second postoperative computer angiograms were obtained. A generalised structural equation model was created to analyse the predictive utility of TL:FL ratio.

Results

One hundred and twenty-five patients underwent surgical intervention, of whom 97 patients were eventually discharged and analysed for postoperative complications. A total of 19 patients were included in the final analysis. Patients with late postoperative aortic complications had a significantly higher FL volume and total-L volume on the first (FL volume P = 0.041, total-L volume P = 0.05) and second (FL volume P = 0.01, total-L volume P = 0.007) postoperative scans. The odds of having aortic complications were raised by 1% with a 1 cm³ increase in total-L volume and by 2% with a 1 cm³ increase in FL volume. The TL:FL ratio was significantly lower in patients who developed complications.

Conclusion

Postoperative CT volumetric measurements in patients who developed complications are characterised by a significant increase in the FL volume and total-L volume from the first postoperative scans. Patients with disproportionately expanded FL presenting with TL:FL ratios less than 1 were associated with aortic complications. Hence, the TL:FL ratio may be a reliable and useful parameter to monitor postoperative disease progression and to evaluate the risk of late complications in ATAAD patients.

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.

Successful endovascular management of multiple mycotic aneurysms after liver transplantation - A case report and review of the literature

Background

Mycotic vascular complications after liver transplantation are rare but can be pose a serious threat to the liver graft and the patient’s life. Mycotic complications can present as an incidental finding on routine imaging, or as haemorrhagic shock. Traditionally, these mycotic vascular complications were managed with open surgery.

Method/results

In this case report, we describe a patient who had developed multiple sequential mycotic aneurysms after liver transplantation which were managed successfully using endovascular and percutaneous techniques.

Conclusion

An endovascular approach is minimally invasive and will be the way forward in managing these mycotic vascular complications.

Autologous or homologous transfusion in aortic surgery: randomized trial

Background

Aortic surgery often requires blood transfusion, which may cause complications and postoperative infection. Autologous transfusion was evaluated in a multicentre clinical trial.

Methods

Some 145 patients undergoing elective aortic surgery in eight hospitals were randomized to either ‘homologous’ or ‘autologous’ transfusion, a combination of acute normovolaemic haemodilution (ANH) and intraoperative cell salvage. Homologous blood was administered when the haemoglobin concentration fell below 8 g dl−1.

Results

Median (interquartile range (i.q.r.)) blood loss was 668 (400–862) ml or 17 (10–24) per cent of blood volume in aortobifemoral bypass, and 1120 (765–1700) ml or 24 (17–36) per cent in aneurysm repair (P &lt; 0·001). Autologous transfusion reduced homologous blood requirements from a median (i.q.r.) of 2 (0–4) units to 0 (0–2) units (P = 0·008). Independent predictors of blood transfusion were homologous transfusion strategy (odds ratio (OR) 2·3 (95 per cent confidence interval 1·1–5·0); P = 0·03), low preoperative haemoglobin concentration (OR 3·7 (1·7–8·2); P &lt; 0·001), prolonged surgery (OR 2·1 (1·0–4·8); P = 0·05) and blood loss (OR 3·0 (1·4–6·5); P = 0·007). Patients with a preoperative haemoglobin concentration greater than 13·5 g dl−1 and who lost less than 20 per cent of their blood volume rarely required transfusion. There was no significant difference between the groups in terms of morbidity, mortality and postoperative hospital stay.

Conclusion

Autologous transfusion reduced the need for homologous blood in aortic surgery, but was useful only in patients with low haemoglobin levels or when blood loss exceeded 20 per cent of the blood volume. ANH alone is indicated for patients undergoing aortobifemoral bypass and in those with a higher haemoglobin level and blood volume.

Economic evaluation of a randomized clinical trial of haemodilution with cell salvage in aortic surgery

BACKGROUND

This study evaluated the costs of acute normovolaemic haemodilution (ANH) and intraoperative cell salvage (ICS) versus homologous blood transfusion in aortic surgery in a prospective multicentre randomized trial.

METHODS

One hundred and forty-five patients were randomized either to standard transfusion practice (homologous) or to a combination of ANH and ICS (autologous). Costs for each inpatient admission were identified. Cell salvage costs were assigned on the assumption that 50 operations were done each year employing a trained cell salvage operator. The results were analysed statistically using bias-corrected bootstrap analysis.

RESULTS

Patients who had transfusion of homologous blood received some 251 units and those having a homologous transfusion received 103 units (P = 0.008). There was no difference in morbidity, mortality and duration of hospital stay. Transfusion-related mean costs were similar at 340 UK pounds for patients having a homologous transfusion and 357 UK pounds for those receiving autologous blood (mean difference 17 UK pounds (95 per cent confidence interval [c.i.]--184 UK pounds to 174 UK pounds); P not significant). There was also no significant difference in mean overall costs: 5859 UK pounds for homologous and 5384 UK pounds for autologous transfusion (mean difference--475 UK pounds (95 per cent c.i.--2231 UK pounds to 1342 UK pounds)). Sensitivity analysis showed that costs remained similar for 20 and 150 operations per annum. Exclusion of a dedicated cell salvage operator reduced autologous transfusion costs but did not have a significant impact on overall cost.

CONCLUSION

Autologous transfusion is cost neutral in aortic surgery even when surgical activity is low.