Journal of The Egyptian Society of Nephrology and Transplantation

ORIGINAL ARTICLE
Year
: 2020  |  Volume : 20  |  Issue : 3  |  Page : 157--164

Complications of permanent vascular access in hemodialysis patients


Kinan Abdosh, Ibrahim Suliman, Ghanim Ahmed 
 Department of Nephrology, Hemodialysis Unit, Department of Vascular Surgery, Tishreen University Hospital, Lattakia, Syria

Correspondence Address:
Dr. Kinan Abdosh
Lattakia, Syria, MSc, Zip Code 22743
Syria

Abstract

Background Vascular access (VA) complications are still considered a significant cause of morbidity and mortality in hemodialysis (HD) patients. The research aimed to study the complications of permanent VA in HD patients: single-center experience. Patients and methods This was a 1-year prospective, observational study conducted in a HD Unit, Department of Nephrology in 2018. 230 HD patients were recruited for the study, and they were subjected to clinical examination in each HD session. Culture and sensitivity of a swab sample of the VA was performed to confirm the diagnosis of infection. Also, Doppler ultrasound was used to evaluate the VA when there had been a suspicion of complications. Data were analyzed using the software Statistical Package for The Social Sciences. Results Arteriovenous fistula (AVF) was the predominant VA, and radiocephalic AVF was the most common type, followed by the brachiocephalic type. The most frequent complication was aneurysm (39.6%), followed by thrombosis (7%), stenosis (5.2%), infection (4.3%), and arterial steal syndrome (2.2%). Thrombosis was the leading cause of AVF failure, and antiplatelet therapy was a protective factor from thrombosis. Infection was the second cause of VA failure and Staphylococcus aureus infection was the most common type. Elbow AVF was considered as a predisposing risk factor of arterial steal syndrome. Conclusion VA complications are not rare, and they could cause VA failure. So, it is necessary to make more efforts and work as a multidisciplinary team.



How to cite this article:
Abdosh K, Suliman I, Ahmed G. Complications of permanent vascular access in hemodialysis patients.J Egypt Soc Nephrol Transplant 2020;20:157-164


How to cite this URL:
Abdosh K, Suliman I, Ahmed G. Complications of permanent vascular access in hemodialysis patients. J Egypt Soc Nephrol Transplant [serial online] 2020 [cited 2020 Dec 6 ];20:157-164
Available from: http://www.jesnt.eg.net/text.asp?2020/20/3/157/290012


Full Text



 Introduction



Despite the technological advances made in the field of hemodialysis (HD), vascular access (VA) continues to be a significant economic, surgical, and logistic problem for both patients and their health-care providers [1].

The effective permanent VA is considered as a safety valve of HD patients, as long-term patency of VA has prolonged survival of thousands of HD patients. So, nephrologists always search for the ideal VA which should have fewer complications, require fewer reinterventions, and improve patient survival.

VA complications are an enormous burden in the chronic HD population. Morbidity related to VA is the leading cause of hospitalization among patients who receive chronic HD and is associated with an estimated cost to Medicare of nearly $1 billion annually [2].

KDOQI recommends that all patients with stage IV or stage V chronic kidney disease who opt for HD should undergo autologous fistula creation, and also recommends a radiocephalic arteriovenous fistula (AVF) as the first and best option. If not feasible, then a brachiocephalic AVF, followed by a basilic vein transposition. Prosthetic arteriovenous grafts (AVG) and tunneled dialysis catheters (TC) are mentioned as last resorts in patients with no autologous options [3].

The aim of our research was to study the complications of permanent VA in HD patients: single-center experience.

 Patients and methods



This was a prospective, observational study involving 230 HD patients in the HD unit of Tishreen University Hospital in 2018. This study was approved by the Research Ethics Committee of the Faculty of Medicine at Tishreen University. All patients included in this study gave written informed consent to participate in this research. All patients included in this research gave written informed consent to publish the data contained within this study. If the patient was less than 16 years old, deceased, or unconscious when consent for publication was requested, written informed consent for the publication of this data was given by his/her parent or legal guardian. The data sets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Inclusion criteria

Those included in the study were:HD patients who were receiving HD treatment via a permanent VA (AVF, AVG, or TC).

Exclusion criteria

Those excluded from the study were:HD patients who were receiving HD treatment via a temporary HD catheter.HD patients who had AVF or AVG but was not mature yet.

Collected and documented data included: demographics (sex, age), history of diabetes and hypertension, smoking, antiplatelet therapy, commencement date of HD, duration of HD treatment, type of VA, site of VA, arteriovenous anastomosis type (radiocephalic, brachiocephalic, or brachiobasilic), and number of HD sessions per week.

The complications studied were aneurysm, infection, stenosis, thrombosis, and arterial steal syndrome.

All patients were subjected to clinical examination every HD session (assessing VA patency by palpation for a thrill, auscultation for a bruit, arm elevation test, and pulse augmentation test).

When there was a suspicion of infection, a swab sample from the skin covering the VA had been taken for culture and sensitivity. Also, Doppler ultrasound (DUS) examination had been performed for 126 patients to evaluate the VA when there was a suspicion of aneurysm, stenosis, thrombosis, or arterial steal syndrome. Venography was not performed because it was not available.

Statistical analysis

Parameters were expressed in percentage or mean±SD. χ2 test was used for qualitative data (frequency and proportion). The risk factors of complications were analyzed by logistic regression analysis. P was considered statistically significant if less than 0.05 at a confidence interval of 95%.

Data were collected and analyzed using the Software Statistical Package for the Social Sciences (version 20).

 Results



Of the 230 patients, there were 100 women (43.5%) and 130 men (56.5%). The majority of them (43%) were in the 51–70-year age group; (36.1%) of them were in the 31–50-years age group ([Table 1]).Of the patients, 92 (40%) were smokers, while 138 (60%) were nonsmokers. Also, most of them (59.1%) were taking antiplatelet agents (aspirin or clopidogrel), while 40.9% were not.{Table 1}

Distribution of permanent VA types

The majority of patients (227) were dialyzed through an AVF, while two were dialyzed through an AVG, and only one was dialyzed through a permanent TC ([Figure 1]).{Figure 1}

All AVFs and AVGs were in the upper limbs and the TC was placed in the right internal jugular vein. As for the AVF site, it was in the wrist (67.4%) and in the elbow (32.6%) ([Figure 2]).{Figure 2}

For the type of AVF anastomosis, it was left radiocephalic in most cases (59.5%), followed by left brachiocephalic in (19.4%) of them ([Figure 3]).{Figure 3}

Complications of arteriovenous fistula

DUS was the chosen procedure to confirm the diagnosis of aneurysms, thrombosis, stenosis, and arterial steal syndrome. It was performed in 126 cases in which the clinical examination was indicative of one of these complications.

On the basis of DUS reports, diagnosis of 91 cases of aneurysms was confirmed, and there were 16 cases of thrombosis, five cases of arterial steal syndrome, and 12 cases of stenosis. Also, there was a clinical suspicion of stenosis in two other cases, but the diagnosis was denied via DUS ([Table 2]).{Table 2}

The most frequent complication in our study was aneurysm (39.6%), followed by thrombosis (7%), stenosis (5.2%), infection (4.3%), and arterial steal syndrome (2.2%) ([Figure 4]).{Figure 4}

Thrombosis was the leading cause of AVF failure (93.75%), followed by infection (40%), stenosis (25%), and arterial steal syndrome (20%).

Despite the common prevalence of aneurysms, this complication did not cause failure of AVF at all.

Staphylococcus aureus infection was the most common type of infection (80%), followed by Staphylococcus epidermidis (20%).

No complications related to AVG or TC were observed during the study.

Statistical analysis showed a significant relationship between infection and the duration of HD treatment (P=0.043); there was also no significant relationship between arterial steal syndrome and both of AVF site (P=0.003) and anastomosis type (P=0.006). On the other hand, there was no statistically significant relationship between stenosis and any of the studied variables. Also, it showed a significant relationship between aneurysm and patient’s age, diabetes, and the duration of HD treatment (P=0.018, 0.006, <0.001, respectively), and ultimately there was a significant relationship between thrombosis and both of antiplatelet therapy and AVF anastomosis type (P=0.007, 0.043, respectively) ([Table 3] and [Table 4]).{Table 3}{Table 4}

Risk factors of vascular access complications

When logistic regression analysis was performed, we found a significant increase in the risk of infection in patients whose HD treatment duration exceeded 6 years (P=0.043), and a significant increase in the risk of arterial steal syndrome with elbow AVF (P=0.006); also, we found a significant increase in the risk of aneurysms with all groups of patients: those with diabetes, age older than 50 years, and extended HD treatment for more than 3 years (P<0.001, 0.009, <0.001, respectively).

Ultimately, we found a significant decrease in the risk of thrombosis in patients who were taking antiplatelet agents (P=0.006).

 Discussion



Establishing and maintaining a proper VA is necessary for successful HD treatment, and AVF is considered to be the best VA, and the preferred site is the wrist, preferably in the nondependent arm.

AVF complications in our study were aneurysm (39.6%), thrombosis (7%), stenosis (5.2%), infection (4.3%), and arterial steal syndrome (2.2%). This goes hand in hand with the study of Derakhshanfar and his colleagues, who reported that the most frequent complications of AVF are aneurysm (51%), followed by venous hypertension (16.7%), infection (4.4%), thrombosis (3.3%), and arterial steal syndrome (1.1%) [4]. Furthermore, in the context of comparison, our study does not go in harmony with both of a Sudanese study conducted by Ahmed and his colleagues, who reported that thrombosis is the most common complication (20.5%), then aneurysm (5.5%), then infection (4.1%) [5], and a Moroccan study conducted by Medkouri et al. [1], who found the incidence rates of thrombosis is 26.4%, aneurysm 3.8%, stenosis 2%, and steal syndrome is 0.5%, and with a Chinese study which also found thrombosis as the most frequent complication (13.86%), followed by aneurysm (12.23%), anastomotic stenosis (2.17%), arterial steal syndrome (1.63%), and infection (0.54%) [6].

Also in the same field, our results do not match the results of Ghonemy and colleagues, who reported that VA stenosis is the most common complication (57%), and the least common complication is aneurysm (13.6%) [7]. Ultimately, Susan and Pawar reported some different incidence rates of infection 1.7%, stenosis 1.7%, thrombosis 18.6%, aneurysm 4.23%, and arterial steal syndrome 0% [8].

Regarding the prevalence of aneurysms in our study, we think that the main reason explaining the high rate is repeated cannulation at the same points.

We found that thrombosis is the main cause of AVF failure, and this goes in agreement with all of the studies conducted by Nakagawa et al. [9], Ahmed et al. [5], and Fitzgerald et al. [10], who all reported that AVF failure occurs mainly due to thrombosis, while incompatible with each of the studies conducted by Tarek et al. [7] and by Mauricio et al. [11], who reported the stenosis to be the most common risk factor of VA failure.

Approximately, one-third of access thrombosis occurs in the absence of anatomic lesions. These episodes may result from conditions that decrease fistula blood flow, such as hypotension, decreased cardiac output, hypovolemia, or prolonged compression of the fistula during sleep. However, nonstenosis-associated access thrombosis is usually due to excessive fistula compression by the dialysis staff to achieve hemostasis after dialysis [12].

Regarding AVF infection, we found that the predominant bacterial pattern responsible for infection is S. aureus (80%), followed by S. epidermidis (20%). This goes hand in hand with the result reported by Tarek et al. [7], who additionally showed an increased risk of AVF infection in male and diabetic patients. Furthermore, we found that prolonged HD duration is the only risk factor of AVF infection, and this may be due to increased exposure to cannulation, given that the occurrence of AVF infection is closely related to personal skills and techniques used by the cannulation staff.Also in the same study by Tarek et al. [7], no significant differences were reported between age and both of stenosis and aneurysm, and this goes in agreement with our study regarding stenosis, while contrary to their result we found advanced age to be a predisposing risk factor for VA aneurysms.

In our study, diabetes was not a risk factor for thrombosis, and this goes in harmony with the result reported by Medkouri and his colleagues [1].

Our study showed that antiplatelet agents are effective in preventing AVF thrombosis, and this is consistent with the meta-analysis study conducted by Osborn et al. [13], who confirmed the beneficial effect of antiplatelet treatment as an adjuvant used to increase the patency of A-V fistulae and grafts in the short term.

Also, from the results a significant increase was observed in the risk of arterial steal syndrome with elbow AVF, while in the study of Yu et al. [6], there is no difference in the occurrence of arterial steal syndrome between elbow and wrist AVFs.

 Conclusion



VA complications are not rare, and they could cause loss of access function, which may adversely affect patient survival. Therefore, more efforts should be made in the context of VA care, through closely monitoring by frequent clinical examination and some other investigations especially DUS.

It is better to take aspirin or clopidogrel to reduce the occurrence of AVF thrombosis, unless there is a contraindication.

We emphasize the importance of establishing wrist AVF as the first option. Additionally, with this type of AVF, arterial steal syndrome could be minimized compared with elbow AVF.

Ultimately, we encourage to work as a multidisciplinary team composed of nephrologists, vascular surgeons, and HD nurses.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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