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REVIEW ARTICLE
Year : 2022 | Volume
: 9
| Issue : 4 | Page : 281-286
Lower limb dialysis grafts: Are they really that bad?
Amrita Patkar, Sumanshi Singh, Neha Kalwadia, Rishabh Gadhavi, R Sekhar
Department of Vascular and Endovascular Surgery, Kokilaben Dhirubhai Ambani Hospital, Mumbai, Maharashtra, India
Correspondence Address:
R Sekhar
Department of Vascular and Endovascular Surgery, Kokilaben Dhirubhai Ambani Hospital, Mumbai, Maharashtra
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/ijves.ijves_41_22
The exponential rise in diabetes in India has led to a steady rise in end-stage renal disease patients requiring renal replacement therapy (RRT). Affordability and access to centers providing RRT and maintenance of functioning upper extremity vascular access for prolonged periods remain a challenge. Frequently facing no upper extremity access situations, we decided to reassess the feasibility of lower extremity vascular access. A retrospective study was carried out evaluating data from January 2009 to March 2022 including patients with a graft tunneled in the thigh (lower superficial femoral artery end to side to terminal great saphenous vein end to end). Totally 26 cases were studied with respect to age, sex, body mass index, comorbidities, difficulty in cannulation, complications, graft dysfunction, and patency rates. Follow-up was a dynamic ongoing process without a fixed endpoint. Graft dysfunction was seen in seven of 26 patients (26.92%), with a primary patency rate of 88.46% (23/26) at 1 year. Twelve subjects died during the study period, however, all had a functioning lower limb arteriovenous graft (AVG). Lack of surgical training, fear of complications, and absence of team approach in decision-making are some reasons why lower extremity permanent dialysis access is infrequently used. However, in view of increased survival on dialysis, advancing age of the dialysis population, associated comorbidities, and multiple access failures, lower limb AVGs may be considered a feasible access modality with acceptable patency rates and minimal complications.
Keywords: Arteriovenous grafts, hemodialysis, lower extremity, vascular access
An exponential rise in diabetes in our country, has led to a steady rise in end-stage renal disease (ESRD) patients requiring renal replacement therapy (RRT). Maintenance hemodialysis (MHD) is the most common modality of dialysis therapy for ESRD worldwide.[1] This requires stable bloodstream access for dialysis to be performed. Three major types of vascular access for MHD are available: primary arteriovenous fistulas (AVFs), AV grafts, and tunneled hemodialysis catheters.
Affordability of RRT and access to centers providing the same are major issues in India. Maintaining a functioning upper extremity vascular access for prolonged periods remains another challenge for all stakeholders in patient care of this subset of patients.
Frequently encountered difficulties in clinical practice include:
Early cannulation of AVF before adequate maturation, which leads to limited lifespan of the fistulaInappropriate cannulation by dialysis unit personnel, occasionally in centers with less than perfect conditions of asepsisHigh incidence/low threshold for central venous access lines which leads to increased incidence of central stenosisLow threshold for stenting of central veins and therefore a high incidence of occluded stentsAbsence of surveillance programs for failing fistulae.Several studies have shown that the outcome of thigh grafts is similar to that of arm grafts;[2],[3],[4] however, lack of adequate surgical training, fear of complications such as infection and leg ischemia, and absence of a team approach in the overall decision-making process are some reasons why lower extremity permanent dialysis vascular access remains an infrequently used option [Figure 1].
Figure 1: Available lower extremity vascular access options. AVF: Arteriovenous fistula, AVG: Arteriovenous graft, CVC: Central venous catheter, SFA: Superficial femoral artery, GSV: Great saphenous vein, PTA: Posterior tibial arteryFrequently facing a no upper extremity access situation, we decided to reassess the feasibility of lower extremity access, which continues to be a sort of taboo in our country.
Materials and MethodsThis was a retrospective study wherein medical records and data of patients from January 2009 to March 2022 were reviewed. We looked at demographic data such as age, sex, body mass index (BMI), and comorbidities as well as postoperative outcomes such as difficulty in cannulation, complications such as infection and distal limb ischemia, graft dysfunction, and patency rates. Follow-up data were a dynamic ongoing process with no fixed endpoint.
Technical details
All patients underwent a thorough clinical examination for screening of lower limb arterial disease. This was followed by a preprocedure duplex study and a computed tomography angiogram of the lower limb as per the surgeon's discretion to rule out significant arterial occlusive disease. A robust profunda femoris artery on the operative limb was ensured. Patients found to have moderate-to-severe peripheral vascular disease, and therefore, an increased risk of distal limb ischemia post-AV graft placement, were not taken up for the procedure [Figure 2].
Figure 2: Algorithm followed for patient selection and postprocedure management. SFA: Superficial femoral artery, GSV: Great saphenous vein, CT: Computed tomographyOnce patients were optimized, a mid-thigh AV graft procedure was carried out under regional anesthesia, with a femoral block being preferred. An expanded polytetrafluoroethylene (ePTFE) heparin-bonded (Propaten®WL Gore®) 7 mm tapered graft was tunneled with an end-to-side anastomosis of the distal superficial femoral artery in the lower thigh and end-to-end anastomosis of the terminal part of great saphenous vein (GSV), in the upper thigh, about a hands breadth below the groin crease [Figure 3], [Figure 4], [Figure 5] and [Figure 6].
Figure 3: Mid-thigh SFA-to-GSV ePTFE graft. SFA: Superficial femoral artery, GSV: Great saphenous vein, ePTFE: Expanded polytetrafluoroethylene
Figure 4: Graft-to-distal SFA end to side. SFA: Superficial femoral artery
Figure 5: GSV-to-graft end to end in the upper thigh. GSV: Great saphenous veinWe do not endorse GSV transposition in the thigh as a convenient option for synthetic grafts because in our experience, unlike upper arm veins, the GSV being a more resilient vein (as evident from its use for arterial/coronary bypasses) tends to not undergo adequate dilatation and “maturation” to be easily cannulated by technicians/nurses in dialysis units. Hence, ePTFE grafts were the preferred primary choice for our leg conduit.
Cannulation was recommended not earlier than 2 weeks, giving time for operative edema to settle. Graft surveillance was conducted either physically in the dialysis unit of our hospital by outpatient department follow-up or by teleconsultation.
Patients were referred back to us by the dialysis team if there were any clinical indicators of stenosis or graft dysfunction such as difficulty in cannulation, excessive bleeding, high venous pressures, etc., or if a reduction of more than 25% in access flow was noted.
ResultsA total of 26 cases were studied.
The age ranged from 42 years (youngest) to 78 years (oldest) with the mean age being 63.5 years [Table 1].
There were 19 male and 7 female patients [Table 2].
BMI was <25 in 14 patients, and more than 30 in one patient with the average BMI being 24.48 kg/m2[Table 3].
Out of the 26 ESRD patients studied, 23 (88.46%) were found to have diabetes mellitus and all of these 23 patients were on some form of treatment such as oral hypoglycemic agents or subcutaneous insulin injections [Table 4].
Graft dysfunction was seen in seven of 26 patients (26.92%), with the first reference being for one patient between 3 and 6 months, two patients between 6 and 12 months, and four patients after 12 months. All of these required open revision of the venous end under local anesthesia along with embolectomy in four cases [Table 5] and [Figure 7].
A primary patency rate of 88.46% (23/26) at 1 year and 82.60% (19/23) assisted primary patency at 2 years were observed.
Twelve participants, unfortunately, died during the study period due to various medical comorbid conditions, thus the mortality rate among the study population was 46.15%. However, all these participants had a functioning lower limb AV graft (AVG) at that time.
We did not see any cases of severe graft infection requiring explantation of graft in our study group. No cases of distal limb ischemia secondary to the procedure were observed either. All graft dysfunction was presented to us by referral from the dialysis department with issues of poor flow and excess puncture site bleeding. Patients requiring embolectomy came directly to us complaining of the absence of thrill.
None of these patients have a transplant lined up. The longest-living patient has an implantation 3.5 years ago and commutes by suburban train to her HD center!
DiscussionOne of the major challenges in India is the expectancy of long-term single access in the background of poor conversion to renal transplant.
The current guidelines recommend upper extremity AVFs as the preferred vascular access for patients on hemodialysis.[5] Prosthetic AV grafts are the next preferred option followed by central venous catheters. It is only when all the available upper limb vasculature has been completely exhausted that the lower extremity is considered for vascular access.
Lower extremity AVFs or AV grafts have both been shown to have acceptable patency rates and infectious complications, provided patient selection has been done appropriately.[3],[6],[7],[8],[9],[10] A large number of studies show that femoral access can be safely created and used in selected patients, however, most patients, once they run out of access options in the arm, end up having tunneled dialysis catheters. This is due to multiple factors and largely related to limited surgical experience with lower limb vascular access creation and concerns of infection due to the anatomical location of the access near the groin [Table 6].
A historically high rate of femoral graft loss due to thrombosis with some studies showing more than 50% of grafts being lost by 1 year[11],[12] has also led to a reluctance in their use in clinical practice. However, with the current advances in endovascular procedures, early graft loss due to thrombosis is less of a concern as thrombosed femoral grafts can be effectively salvaged with timely intervention.
Keeping the access site clean is of utmost importance for any type of access, including femoral grafts. Infections are also usually a result of graft cannulation, hence necessitating conditions of strict asepsis. Ong et al. evaluated the long-term outcomes of leg grafts when compared to tunneled internal jugular catheters and found that leg grafts were superior in terms of both patency and infection rates.[7]
Similar patency rates have been reported between AVFs and AVGs, irrespective of location (upper arm, forearm, or thigh) while infection and thrombosis rates were higher with AVG compared with AVF; however, access salvage after a thrombotic event was found to be superior with AVG.[13]
The primary and secondary patency rates for lower extremity AVGs have been reported as 34%–62% and 41%–83%, respectively, with an infection rate of up to 46%.[12],[14],[15] Geenen et al. in the largest reported series of 153 lower extremities AVGs reported an infection rate of 27%.[16] Ram et al. reported a longer survival in thigh AVGs as compared with upper arm AVGs and upper arm AVFs (47% vs. 11% and 3% at 5 years, respectively).[8] All these factors significantly add to survival time on dialysis.
In addition to these factors, the thigh graft is also cosmetically preferable to upper extremity grafts and fistulas as it can be well concealed when not in use. A lower extremity access also gives the patients an option for self-cannulation as both their arms are free for use during dialysis sessions. On the other hand, cannulation of the thigh graft by dialysis technicians as also the need for frequent observation of the graft during hemodialysis results in the invasion of the patient's privacy.[20]
ConclusionIn carefully selected patients, lower limb grafts can provide good vascular access, with short-term patency rates and infectious complication rates that are comparable with upper limb fistulas and grafts. The lack of infection in our study is possibly due to the site of implantation and cannulation being in the mid-thigh, well away from the groin. With regular surveillance and early and timely intervention, a good long-term patency rate is also achievable.
In view of multiple factors such as an increased survival on dialysis, advancing age of the dialysis population, associated comorbidities, and multiple access failures, lower limb AVGs may be considered a feasible access modality with acceptable patency rates and minimal complications.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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