Servier – Phlebolymphology

1.6.1 Tunneled catheters

Prevention and treatment of sepsis.
J. Pengloan

According to the author, tunneled catheters (TCs) are essential devices for patients on hemodialysis, but are frequently associated with high levels of morbidity and mortality due to an inflammatory process or infection. Development of an intraluminal bacterial biofilm is the cause of bacteremia and abscesses may occur during the introduction of bacteria from skin flora during the connection and disconnection of TCs. The treatment is based on the association of a systemic antibiotic lock solution with a fibrinolytic treatment of TC that should be continued at least 2 weeks after the bacterial cultures are negative. Staff training is mandatory to avoid this complication.

When should an infected catheter be changed?
B. Canaud

Infection remains a major burden for hemodialysis patients, representing the second cause of hospitalization and mortality. There are different pathogenic pathways involved and include infected thrombus, track infection, exit skin infection, endoluminal contamination, and the catheter biofilm. The most frequent pathogen is Staphylococcus sp representing more than 50% of infections. Infective endocarditis is associated with high mortality in hemodialysis patients. Diagnosing catheter-related infections is very important with clinical observations, such as the presence of local or systemic symptoms, clinical vigilance, and monitoring of the catheter. In the diagnosis of microbial infections, identifying pathogenic microorganisms is mandatory through swabbing of culture skin exudates and the catheter hub, blood cultures, Gram staining, microorganism determination, and antibiotic testing.

The uncomplicated catheter (no skin exit infection, no fever, no systemic reaction, negative blood culture, no risk factor, favorable microorganism type) may be retained with local skin therapy, systemic antibiotics, and close monitoring. The complicated catheter (tunnel infection, sepsis, positive blood culture) must be removed and treated with systemic antibiotic therapy for 6 to 8 weeks with close and prolonged monitoring.

Catheter-related infections and blood stream infections should be considered as serious events in hemodialysis patients. Management of catheter-related infections should follow strict rules of the best clinical practices and close patient monitoring.

Difficult catheter insertions.
R. Shoenfeld

The incidence of central vein stenosis or occlusion in patients in chronic dialysis is highly significant (up to 42%). The central vein patency is a prerequisite for optimum chronic dialysis catheter tip position. Alternative cannulation may be safely performed via external jugular or other suitable collateral veins in or near the neck or by transfemoral or translumbar routes. The patent access sites include the right jugular, left jugular, right femoral, left femoral, translumbar, left subclavian, and right subclavian. The access of last resort is the transhepatic.

New and innovative endovascular recanalization techniques and devices are expanding the frontiers of end-stage vascular access. When possible, exotic central catheter insertions should serve as a pretext or bridge to recanalization and reconstruction of central veins to reclaim lost opportunities for permanent arteriovenous access and to preserve venous capital.

1.6.2 Operative Techniques

Snuffbox fistula.
C. Gibbons

The first citation of a snuffbox fistula was over 30 years ago, but is less frequently used by surgeons than the radiocephalic arteriovenous fistula (AVF) at the wrist. However, it is the most distal fistula, giving the longest forearm cephalic access for needling. The author recommends, when performing a fistula, to stay as distal as possible, avoid grafts, and use the nondominant arm as the first option. The forearm AV fistula is easier to needle and more comfortable for the patient, reducing the incidence of steal.

The indications for snuffbox AV fistula include veins >2 mm, arteries >1.6 mm (perhaps 2 mm for women). The snuffbox fistula is possible as a primary access in 53% of cases for indication of AV fistula.

In conclusion, snuffbox has similar patency to wrist AVF, gives longer vein length, preserves the venous “capital,” and still allows wrist AVF in 45% of patients, if failure occurs.

References:
Shemesh D et al. Cardiovasc Surg. 2003;11:35-41; Biukians A et al. J Vasc Surg. 2008;47:415-421.

Middle forearm fistula.
G. Bonforte

The American and European guidelines recommend the distal wrist radial-cephalic fistula, proposed by Cimino-Brescia, as the first and best for hemodialysis access. This arteriovenous fistula requires easy placement, preservation of the patient’s vascular network, and needs fewer interventions for complications (infection, stenosis, and thrombosis) compared with grafts and central venous catheters.

To avoid steal syndrome complications, the author recommends that a smaller-sized anastomosis be performed in relationship to the size of the brachial artery to limit the flow through the fistula.

In the last 30 years, the hemodialysis population has become older and sicker, comorbid factors have increased, and the life expectancy has been reduced, so nowadays, it is even more important to create a working vascular access with as few complications as possible. According to the author, several studies have shown that the classic distal radiocephalic (DRCF) fistula has an increased rate of early failure (early thrombosis or failed maturation), therefore, it is correct to wonder if the DRCF still represents the best first choice for vascular access. The middle-arm fistula (MAF) is suggested as an alternative option.

The selection criteria for MAF for primary arteriovenous fistula (AVF) include: (i) insufficient vessel diameter for successful DRCF creation; and (ii) two or more comorbid factors among: diabetes mellitus, atherosclerosis, obesity, neoplasm, coagulation disease, peritoneal dialysis failure, and >65-years-old.

In conclusion, based in the author’s experience, he suggests reconsidering the current recommendations in clinical practice guidelines in an elderly population with ischemic and diabetic nephropathy, although the DRCF remains the first vascular access choice in properly selected patients. The MAF could be proposed as the primary AVF in selected patients when a DRCF is not feasible and as a second step in case of DRCF failure in all patients before attempting to place a brachial artery inflow AVF.

What is the least worst arteriovenous bypass for the upper limb?
M. Lazarides

Despite the fact that the European and USA guidelines recommend the increased use of an autogenous fistula because it has a more durable access once matured, almost 50% of all arteriovenous fistulas (AV) performed fail. Although prosthetic grafts are not superior to the AV fistula (AVF), they present the only choice in selected patients in whom an autogenous fistula simply cannot be constructed.

AVF and grafts are both useful in providing vascular access. An additional indication of prosthetic grafts is the use of short polytetrafluoroethylene segments in revisions of autogenous accesses, without further consumption of venous capital by harvesting veins or compromising more proximal access sites.

For elderly patients with a life expectancy <18 months, a graft is an attractive option.

References:
Rooijens PP et al. J Vasc Surg. 2005;42(3):481-486; Staramos DN et al. Eur J Surg. 2000;166(10):777-781; Sgroi MD et al. J Vasc Surg. 2013;58(2):539-548.

A new sterile elastic exsanguination tourniquet.
E. Landenheim

Arterial tourniquets apply sufficient pressure on a limb to collapse the artery and block the arterial blood supply to the limb. Tourniquets have been in use in military and emergency medicine for hundreds of years. They were introduced to orthopedic surgery in 1873 by Dr Frederic Esmarch. Inflatable cuff tourniquets were adopted for orthopedics by Dr Cushing. All tourniquets are made to apply radial pressure on the circumference of the limb. There are three general types of tourniquets: (i) inflatable or pneumatic cuffs (Cushing); (ii) wrapped elastic or nonelastic bands (Esmarch); and (iii) rolling elastic rings (HemaClear). The elastic exsanguinations tourniquet was patented in 1987 by Dr Noam Graviely. Although the prototypes made by a rubber sleeve only showed some results on upper extremities, they failed to achieve their purpose on lower extremities. Development of a separate constricting element (silicone ring) was required. The elastic exsanguinations tourniquet (HemaClear) consists of a calibrated silicone ring wrapped around an elastic sleeve (stonicket) and straps with handles that are used during the application. It is not pneumatic and is significantly more narrow than a standard pneumatic tourniquet.

The author recommends special precautions to avoid twisted veins when doing vein transportations. Avoid tourniquets in patients with severely atrophic skin and release the tourniquet before closing the incision.

The advantages of a surgical exsanguination tourniquet are that the very narrow footprint expands the potential for tourniquet control, it come in 4 sizes to fit any upper limb from 14 cm to 85 cm and it leads to less blood loss from arteriovenous access procedures, which may result in fewer transfusions.

Reference:
Ladenheim E et al. J Vasc Access. 2013;14(2):116-119.

Tagliatelle technique: a revolution in vascular access to the lower limbs.
B. Boura

In cases when all options of upper vascular access are exhausted, vascular surgeons are required to consider a new lower extremity access. The author proposed the tagliatelle technique, for these cases when all attempts to create a hemodialysis access fail. This technique consists of using the great saphenous vein, harvested from the thigh and just below the knee, which is then longitudinally opened, freed from all valves, forded in 2 to create one anterior and one posterior vein panel, both with a sutured edge, as has already been described for other locations. The final result is a conduit, which doubles the initial diameter suitable for hemodialysis. This conduit is subcutaneously tunneled and then anastomosed end-to-side with the superficial femoral artery in the mid-thigh. The author believes that this technique can be used in other anatomies, such as upper limbs in selected patients.

References:
Correa JA et al. BMC Surg. 2010;10:28; Mallios A et al. Eur J Vasc Endovasc Surg Extra. 2012;23:e40-e41.

1.6.3 Controversy: Small vein and forearm AVF creation

Peroperative technique.
P. Veroux

Ideally, every patient should initiate dialysis with a mature fistula suitable for cannulation, but in the real world, only a minority of patients has a well-functioning arteriovenous fistula (AVF) at the time of starting hemodialysis. The series reporting 1-year latency rates varies from 36% to 62.5%. The most important factors limiting the primary latency of distal autogenous AVF are quality of radial artery inflow and availability of a long patent venous segment with adequate diameter. Veins smaller than 2.5 mm in diameter have been reported to increase immediate failure and decrease the primary latency rate. The purpose of the PBA trial (Primary Balloon Angioplasty) was to evaluate the safety and efficacy of a new technique, the Primary balloon angioplasty, used to increase the cephalic vein diameter at the time of AVF creation, compared with the standard hydrostatic dilation technique. The inclusion criteria were a radial artery with normal duplex ultrasound parameters and a cephalic vein with a diameter less than 2 mm. The exclusion criteria were segmental cephalic vein occlusions and no compliance with antiplatelet therapy. A total of 40 patients were randomized on a 1:1 basis into two groups according to the technique used to increase the vein caliber: hydrostatic dilatation (HD) group (21 patients) and primary balloon angioplasty (PBA) group (19 patients).

The results demonstrated an immediate success in 67% of patients in the HD group and 100% in the PBA group. The mean maturation time was 55 days in the HD group and 33 days in the PBA group.

In conclusion, PBA of very small cephalic veins performed before the creation of a distal AVF for hemodialysis, is a safe and feasible procedure. PBA is associated with excellent latency and maturation.

Postoperative balloon angioplasty.
A. Raynaud

The maturation of a fistula requires arteries to be able to provide a flow of at least 500 mL/min, superficial veins able to develop and to be punctured 3 times a week, and normally patent central veins. Preoperative assessment of artery and vein patency is required before the creation of an access (clinical examination, artery and vein ultrasonography, venography).

A radiocephalic fistula is the first-choice access. When radial arteries or cephalic veins are not suitable, other sites should be considered for access creation, mainly ulnobasilic or a more proximal access. When possibilities of access creation are very limited, the creation of distal access should be considered, despite nonoptimal radial artery or cephalic veins. This is the case when the cephalic veins are small.

When a surgeon creates a fistula, he avoids traumatizing the vein because he knows that a tiny trauma often engages a process leading to stenosis. He takes care to obtain a harmonious and regular anastomosis because he knows that turbulences will traumatize the venous wall and will cause a postanastomotic stenosis. Dilatation causes major parietal damages.

The peroperative dilatation of a vein whose diameter is underestimated is not only useless, but is also deleterious. Dilation causes major parietal damages leading to a risk of rupture, a high risk of early thrombosis, and a very high risk of delayed stenosis (80%). Compared with postoperative dilatation, the risk of complications appears higher with the venous wall not being developed at all; therefore, the access flow is lower and the vein is more prone to spasm. The postoperative dilatation is achieved only when necessary, and is safer because it is achieved on partly developed veins. There are fewer risks of ruptures if the dilatation is performed on somewhat enlarged venous walls. There are fewer risks of early thrombosis because of the higher flow, which favors venous wall remodeling and the risks of spasms are lower.

In conclusion, the author considers peroperative dilatation seldom evoked, because when a doubt exists about the abilities of a cephalic vein to mature, the access is created on another site. The peroperative dilatation of a small vein along its entire length is inconceivable for the author for several reasons including: (i) the vein could be large enough, but its diameter may be underestimated by ultrasonography in which case a peroperative dilatation is useless and deleterious; (ii) a small, but normal vein will maturate alone only requiring a little more time; and (iii) dilatation of a thin vein wall has a high risk of rupture, early occlusion, and secondary stenosis.

Postoperative dilatations are performed only when needed. The maturation failure is due to insufficient flow (due to overlooked preexisting venous or artery lesions) and lesions occurring after the fistula creation. Postoperative dilatation is safer when attempted on a partly mature fistula with a larger diameter, more resistant wall, higher flow, and less risks of spasm.

1.6.4 Lecture

Vascular steal and ischemia after vascular access creation.
P. Bourquelet

The ischemia after arteriovenous fistula (AVF) creation results from the association of high pressure arterial flow (not only retrograde flow coming from the distal artery, but also cut from the proximal artery) and a low-pressure vein. The clinical grading includes cyanosis, mild coldness, pain during dialysis sessions, rest pain, motor dysfunction, limited ulceration or necrosis, and irreversible tissue loss in the hand.

Treatment algorithms for cases of coldness, cyanosis, and pain during dialysis require conservative treatment. In cases of rest pain, motor dysfunction, and limited necrosis, duplex/angiography is mandatory in order to look for artery stenosis. In case of distal necrosis, fistula ligation is necessary.

In conclusion, distal ischemia occurs in 5% to 10% of AVF cases in the elbow. The treatment consists of angioplasty, flow reduction, and AVF ligation.

Puncture ultrasound guidance: to decrease access site complication.
P. Schneider

The author started by presenting the rationale for puncture by ultrasound guidance. In fact, it appears to reduce access site complications (lower risk of hematoma, bleeding, and arteriovenous fistula) by allowing single-wall punctures and first pass, as well as avoiding branches, calcifications, and lesions. It is also optimal for the use of closure devices such as for those used for percutaneous EVAR, as it permits an optimal puncture site placement. Subsequently, the author corroborated these statements by presenting the results of several studies (Gedikoglu M et al. Catheter Cardiovasc Interv. 2013;82:1187-1192; Seto AH et al. JACC Cardiovasc Interv. 2010;3:751-758; Lamperti M et al. Intensive Care Med. 2008;34:2100-2105). He further introduced some tips like: (i) placing the needle 1 to 2 cm above the femoral bifurcation, after finding the profunda; (ii) using imaging to avoid small common femoral artery branches and calcific patches; (iii) placing the needle at a steeper angle in a more calcified or scarred artery; (iv) obtaining a spot film with the needle in place to confirm that the puncture site is below the top of the femoral head to avoid retroperitoneal hematoma.

The author concluded his talk by stating that ultrasound-guided access provides added safety and reduces the most common complications, is readily available, allows a more ideal needle puncture placement, enhances use of closure devices, and brings an opportunity for quality improvement.