Pedro Maia

Doppler Ultrasound: A Powerful Tool for Vascular Access Surveillance

National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) guidelines recommend Doppler ultrasound (DU) for surveillance of vascular access (VA), but trials have not been unanimous about its benefit on VA patency. The aim of this study was to evaluate the accuracy of DU for patency, as well as to highlight additional data provided by this method. A transversal study was conducted to evaluate DU method in correlation with BTM using paired t‐test and Pearson test. Ultrasonography evaluation was performed with a Siemens Acuson X150 Ultrasound device and BTM‐Qa with the Blood Temperature Monitor BTM®. Access blood flow (Qa) values were correlated with several factors by nonparametric tests. Fifty hemodialysis patients were included, with mean age of 64.5 ± 13.7 years; durations of hemodialysis and VA were 51.4 ± 47.3 and 47.6 ± 42.1 months, respectively. The mean difference between DU and BTM flows was 20.5 ml/minute (p 0.624). Pearson correlation was 0.851 (p < 0.001). DU‐Qa values varied significantly with several factors: type of VA, reason for DU referral, the presence of artery stenosis, and the location and number of stenosis. BTM‐Qa values only varied significantly with the presence and number of stenosis. Various silent abnormalities were detected with DU. DU provides accurate anatomic and hemodynamic data to further knowledge regarding the etiology of stenosis and other abnormalities that compromise VA well functioning.

FP579PRE OPERATIVE ROUTINE ULTRASOUND MAPPING IMPACT ON A VASCULAR ACCESS CENTRE

INTRODUCTION AND AIMS: Achieving functioning arteriovenous fistulae (AVF) in patients with end stage renal disease remains challenging, as the primary failure rate reaches 40% in some series. Despite the lack of indisputable evidence to support routine pre-operative ultrasound examination, the existing Disease Outcomes Quality Initiative guidelines and European Best Practice Guidelines suggest its routine use.

Predictive factors of recurrent endovascular intervention for cephalic arch stenosis after percutaneous transluminal angioplasty

Objective Cephalic arch stenosis (CAS) is an important and recurring problem arising in hemodialysis patients because of the requirement for repeated interventions to maintain patency. The aim of this study was to determine predictive factors for recurrence of CAS after successful angioplasty. Methods A retrospective, case‐control study was conducted at two ambulatory vascular access (VA) centers. All patients with a dysfunctional VA referred for an angiographic procedure and with a documented CAS as evidenced during the endovascular intervention (EI) between January 1, 2013, and December 31, 2015, were enrolled; 15 patients in whom an efficacious intervention was not possible were excluded. The study thus concerned 375 EIs using percutaneous transluminal angioplasty without stent placement on 241 VAs for CAS (9% of all procedures performed) during a 3‐year period. Patients were compared regarding the absence (group 1; n = 181) or presence (group 2; n = 60) of recurrent CAS. We defined recurrence as that which occurred within 180 days of the previous successful EI for CAS. Any CAS diagnosed and treated >180 days after a previous one was considered a novel CAS and not a recurrence. Multivariate analysis was performed to determine variables independently associated with recurrence of CAS. Kaplan‐Meier analysis was performed for determination of primary and assisted primary patency in this population. Results The recurrence rate of CAS was high (25%). Patients in both groups had similar demographic characteristics, time on hemodialysis, and mean dialysis dose and access flow rate at referral (P > .05). Multivariate analysis provided a significant discriminatory influence pertaining to diabetes (hazard ratio [HR], 2.054; 95% confidence interval [CI], 1.22‐3.46; P = .007), residual stenosis even though it was <30% (HR, 1.86; 95% CI, 1.005‐3.439; P = .048), and the finding of an isolated CAS lesion (HR, 0.445; 95% CI, 0.219‐0.905; P = .025) in comparing group 1 and group 2. All other variables lost statistical significance on multivariate analysis. Primary patency at 6 months was 72%, increasing to an assisted primary patency of 89% at 6 months. The median durations of primary patency and assisted primary patency were 9.5 months and 15.6 months, respectively. Conclusions Multivariate analysis showed that diabetes and residual stenosis (albeit <30%) were predictive of recurrence, whereas the finding of an isolated CAS lesion as opposed to stenoses in multiple locations was shown to be negatively associated with recurrent CAS, appearing to be “protective”.

Does pre- and post-angioplasty Doppler ultrasound evaluation help in predicting vascular access outcome?

Background Kidney Disease – Improving Global Outcomes (KDIGO) recommends post-percutaneous transluminal angioplasty (PTA) <30% residual stenosis (RS) and hemodynamic parameters improvement. Primary end point: how post-PTA access blood flow (ABF) improvement predicts vascular access (VA) outcome. Secondary: compare Doppler ultrasound (DU) and angiography diagnostic accuracy; determine how other factors predict outcome. Methods Eighty patients. DU evaluation performed pre- and post-PTA. Several parameters recorded. Secondary patency verified after 6 months. Results Initial ABF 537 ± 248 mL/min; final ABF 1013 ± 354 mL/min. Number and location of stenosis was highly correlated between DU and angiography (p<0.001); central vessels mismatching. First semester overall survival was 63%; significantly better for fistulas (76%) than grafts (51.7%), p 0.044. Final RS>30% associated to better survival, p 0.038. Initial ABF<500 mL/min and multiple stenosis did not affect outcome (p>0.05). A >2-fold ABF increase had no significant impact on fistulas (p>0.05) but was significantly associated with worst outcomes in grafts (23.1% vs. 73.5%, p 0.009). Grafts had lower survival (HR 3.3, p 0.034). Conclusions Although less accurate for central lesions, DU has a key role on VA surveillance, allowing a morphologic and hemodynamic assessment. Angioplasty is effective in preserving VA; however, it may increase restenosis due to accelerated neointimal hyperplasia. Current parameters are not useful. Trials addressing this issue are needed.

Sodium and Potassium Intake, the First Step to Control Arterial Hypertension

In Portugal, Hypertension affects 43% of adults. Salt intake reduction and potassium increase are recommended for prevention and treatment of hypertension. This study was designed to determine how dietary sodium and potassium affects blood pressure (BP). Cross-sectional study of 41 patients was made in Centro Hospitalar de Coimbra. Patients BP, as well as their 24-hour urinary excretion of sodium (UNa) and potassium (UK); UNa/UK ratio was calculated. There were highly significant differences for both diastolic BP (DBP) and sistolic BP (SBP) means according to 24h-UNa and UNa/UK values (p 0.001). There was a highly correlation between BP and 24h-UNa, as well as, UNa/UK; stronger with this latest factor. Among BP values, SBP was strongly influenced by 24h-UNa and UNa/UK than DBP (Pearson 0.608 > 0.578 and 0.675 > 0.633, respectively). So, increased potassium intake should be considered as a recommendation for prevention and treatment of hypertension, especially in those who are unable to reduce their intake of sodium.

Vasculites e ANCA – a propósito de um caso clínico

RESUMO Apreseotamos o caso clinico de um doente de 68 anos de idade, com glomerulonefrite rapidamente progressiva e hemorragia pulmonar, presenca de anticorpos anti-citoplasma dos neutrofilos (padrao perinuclear com especificidade anti-mieloperoxidase), e anticorpos anti-cardiolipina. A histologia renal confirmou o diagnostico de poliarterite microscopica. A proposito deste caso, sao feitas algumas consideracoes sobre a utilidade dos auto-anticorpos no diagnostico das diferentes formas de vasculite.