Successful 8-year use of Venous Window Needle Guide for deep arteriovenous fistula cannulation

We describe the case of a patient who had been on hemodialysis for 8 years using a native arteriovenous fistula cannulated through the Venous Window Needle Guide™ device (VWING). The overall outcome was excellent and complication-free with intact state of the underlying vessel and a high degree of patient satisfaction. The patient was able to carry out self-cannulation without any difficulty almost from the very beginning. The current unavailability of VWING is a missed opportunity in the field of vascular access.

[The Cannulation of the Arteriovenous Fistula in the Presence of a Stent: Precautions, Risks, and Possibilities]

A proper management and tailored interventions represented two fundamental steps to ensure a long-term use of the arteriovenous fistula (AVF). AVF failure can be attributed to various factors, with stenosis being the most common cause. Different techniques are employed for treating complications, but percutaneous endovascular procedures are the most widely used. In addition to angioplasty (PTA), the possibility of utilizing stents, particularly stent grafts (SG), has further improved outcomes. However, the insertion of these devices involves commitment to a segment of the vessel, which may vary in length, making the indication necessitate a careful evaluation. The positioning of a stent graft indeed limits the space for needle insertion, and on the other hand, the cannulation of the device is considered off-label according to technical specification. This work addresses the issue of puncturing these devices. Alongside a rapid overview, we describe a clinical case of continuous cannulation of a multiply stented AVF, for over 9 years, which opens up the discussion about the possibility of long-term cannulation through proper planning.

Report on an Italian survey of 72 stuck hemodialysis catheters

BACKGROUND

Reports of stuck hemodialysis catheters have been on the rise in recent years. Aim of this work is to report how this complication has been managed and the relative outcomes in a multicente Italian survey.

METHODS

Since 2012, the Italian Society of Nephrology (SIN) Project Group of Vascular Access has collected data among nephrologists on this complication. Data regarding 72 cases of stuck tunnelled central venous catheter (tCVC) in 72 patients were retrieved thanks to this survey.

RESULTS

In 11 patients (15%) the stuck catheter was directly buried or left in place. Sixty-one cases were managed through advanced removal techniques. Among these, 47 (77%) stuck tunnelled central venous catheters were successfully removed, while 14 (23%) failed to be withdrawn. Considering removed tCVCs, the use of endoluminal balloon dilatation alone or in combination with other tools showed a percentage of success of 88%. The removal procedure involved numerous specialists. Some complications occurred, such as breakage of the line or bleeding, and two cases of haemopericardium during an advanced procedure.

CONCLUSION

The survey shows how the stuck catheter complication was managed in different ways, with conflicting results. When utilized, endoluminal balloon dilatation proved to be the most effective and most often utilized technique, while some cases had suboptimal management or failure. This underlines how delicate the procedure is, and the need for both precise knowledge of this complication and timely organization of removal attempts.

Venous Window Needle Guide for deep vessels and difficult arteriovenous fistula cannulation

The Venous Window Needle Guide (VWING™) has recently been proposed for patients with difficult arteriovenous fistula (AVF) access for hemodialysis due to deep vessels or other cannulation-related problems. This totally subcutaneous titanium device is sutured onto the upper wall of the matured fistula and may facilitate cannulation by the button-hole technique. We describe our initial experience with nine implants in six patients with a cumulative follow-up of 83 months, and make some experience-based technical suggestions for implant and surveillance radiological imaging. The indication for implantation was deep vessel, previous failure of cannulation or unsuitable site for direct cannulation. No infectious complications were observed during follow-up and proper blood flow was constantly achieved. Some difficulties were occasionally encountered with regard to cannulation; nonetheless, patient satisfaction was not significantly affected. VWING seems to be an interesting option in some patients provided that surgical implantation is carefully carried out and preventive measures against infections are strictly observed.

Acute renal infarction: a single center experience

BACKGROUND

Acute renal infarction is a rare condition whose diagnosis is often delayed. Major risk factors include atrial fibrillation, valvular or ischemic heart disease, renal artery thrombosis/dissection and coagulopathy.

METHODS

We reviewed the medical records of 18 patients admitted to our Nephrology Department between 1999 and 2015 for acute renal infarction diagnosed by computed tomography. Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy was performed in some patients during follow-up to assess parenchymal lesions and estimate differential kidney function.

RESULTS

Mean age was 59.8 years. Major associated risk factors included hypertension (44 %), obesity (33 %), atrial fibrillation (28 %), peripheral vascular disease (17 %), smoking (17 %), prior thromboembolic event (11 %), diabetes (11 %), estroprogestinic therapy (11 %). Seventy-two percent of patients presented with flank pain. Mean serum creatinine was 1.2 ± 0.6 mg/dl. Acute kidney injury occurred as the initial manifestation in two patients. Patients were managed conservatively, with low molecular weight heparin (83 %) or aspirin (11 %). At the end of follow-up serum creatinine was 1.1 ± 0.3 mg/dl; one patient remained on chronic hemodialysis. 58 % of patients who underwent renal scintigraphy after a median of 8 months had a reduced contribution of the previously affected kidney to total renal function.

CONCLUSION

Risk factors associated with the development of chronic kidney disease following renal infarction are unknown. In our subjects, renal function remained stable in all but one patient who developed end stage renal disease. Further studies should focus on etiology and evolution of kidney function in patients with acute renal infarction.

[Effectiveness of oral supplements of folates, vitamins B12 and B6 in hemodialysed patients. Preliminary results after 5 months of follow-up]

BACKGROUND

Elevated serum levels of homocysteine have increasingly been associated as a risk factor of cardiovascular disease. Recent reports demonstrated that supplements of folates, vitamin B12 (B12) and vitamin B6 (B6) are effective in correcting serum Hcy levels in hemodialysed patients.

AIM

to assess the effectiveness of oral supplements of folates, B12 and B6, in order to reduce serum Hcy levels in our cohort of hemodialysed patients.

METHODS

Sixty-one hemodialysed patients have been enrolled in the study (age 68+/-13 years; hemodialysis 62+/-42 months). Oral supplements of calcium folinate (30 mg 3 times a week), B12 (500 mg 3 times a week) and B6 (200 mg 3 times a week) were administered at the end of each hemodialysis session. Serum levels of Hcy, folic acid and B12 were tested at the beginning of the study and at 2 month intervals.

RESULTS

After 5 months of follow-up, serum levels of Hcy were normalised in 19% of our patients and in total 70% of them showed a reduction >8% when compared with the basal Hcy levels. No side effects related to folates, B12 or B6 supplementation were observed.

CONCLUSIONS

Oral supplements of folates, B12 and B6 are a safe and effective treatment of hyperhomocysteinemia in hemodialysed patients.

[Infections from extemporaneous catheters for hemodialysis. Experience in a center]

BACKGROUND AND AIMS

This study reports a retrospective evaluation of the predominance of infection in 67 dual lumen central venous catheters (CVC), 35 of which were positioned in the femoral vein by the nephrological team and 32 in the subclavian vein by anesthetists.

METHODS

The microorganisms responsible for infection, the prevalence of clinically symptomatic infections, the relationship between CVC-correlated infection and the time the catheter remained inserted were evaluated, together with a comparison between the two different insertion sites.

RESULTS

Culture tests, performed using Maki's semiquantitative technique, gave positive results in 16/67 (23.8%) cases. The main pathogenic agents found were Staphylococcus epidermidis (37.5%) and Staphylococcus aureus (31.2%). In 3/16 cases (18.78%) infections were clinically symptomatic. The mean permanence of CVC with positive cultures was not statistically different to the mean permanence of CVC with negative cultures (22.44 +/- 13.48 vs 18.38 +/- 17.76). The microorganisms isolated on femoral and subclavian catheters showed a comparable distribution and the prevalence of infection was not statistically different in the two insertion sites.

CONCLUSIONS

In conclusion, in the absence of infection, the authors tend to keep working catheters in the site, thus avoiding repeated invasive manoeuvres for replacement and/or repositioning, whereas in the presence of suspected systemic infection they feel it is more prudent to remove the CVC without waiting for the results of the hemoculture, starting first empiric and then specific antibiotic treatment on the basis of the antibiogram.

[Evaluation of the hereditary component in patients with essential arterial hypertension]

As is well known, genetic factors play a decisive role in the pathogenesis of essential hypertension (EH), even if they are closely related to environmental factors; it is therefore not possible to quantify with any degree of certainty the role and importance of each in the onset of hypertensive disease. The aim of the present study was to ascertain the presence of hypertensive 1st and 2nd degree ascendant, collaterals and descendants in a group of 355 out-patients with EH (167 males, 188 females; mean age: 52.9 +/- 0.7 years) using an anamnestic analysis. The results of this study confirmed the high prevalence of the hereditary component in EH: familial hypertension was found in 60.6% of the group. From a detailed analysis of the group, with regard to hypertensive ascendant, the hereditary transmission of EH by the mother was significantly higher than that by the father, both the parents and the forefathers, even if it is worth pointing out that the penetration of the genetic character was not always sex-related and was equally distributed between male and female descendents. In addition, it was observed that patients with a familial pattern of hypertension in common with collateral relatives showed significantly enhanced levels of systolic and diastolic pressure in relation to those with another hereditary component. These findings serve to underline the importance of evaluating the effective incidence of EH with regard to an entire family nucleus and not only in individual terms, in order to identify the various means of genetic transmission and possible interactions with environmental factors.