Primary Patency Success of Arteriovenous Shunts in Hemodialysis Patients: A 28-month Prospective Study at Al-Thawra Modern General Hospital, Yemen

doi:10.21203/rs.3.rs-5000183/v1

Download PDF

Research Article

Primary Patency Success of Arteriovenous Shunts in Hemodialysis Patients: A 28-month Prospective Study at Al-Thawra Modern General Hospital, Yemen

https://doi.org/10.21203/rs.3.rs-5000183/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Background:

Arteriovenous (AV) shunts are vital for providing long-term vascular access in hemodialysis patients. While brachiocephalic and radiocephalic shunts are commonly employed, data on their primary patency rates and associated complications in resource-limited settings such as Yemen remain scarce. This study aimed to evaluate the primary patency success of AV shunts and identify factors influencing their outcomes in hemodialysis patients at Al-Thawra Modern General Hospital.

Methods:

This prospective observational study was conducted over 28 months, from April 2021 to August 2023, at Al-Thawra Modern General Hospital in Sana’a, Yemen. A total of 163 patients with chronic renal failure requiring AV shunt creation for hemodialysis were included. Data on patient demographics, comorbidities, shunt characteristics, and postoperative outcomes were collected. Primary patency was assessed at the 8-month follow-up. Statistical analysis was performed to identify factors associated with shunt patency.

Results:

Among the 163 patients included, the median age was 43.12 years, with 61.3% undergoing brachiocephalic shunt creation. The overall primary patency rate at 8 months was 87.7%, with brachiocephalic shunts exhibiting a significantly greater patency rate (93.0%) than radiocephalic shunts (67.3%) (p = 0.02). Complications occurred in 25% of patients, with pseudoaneurysm formation being the most common complication (6.1%). Factors such as shunt type, patient age, and comorbidities (e.g., diabetes) significantly influence patency outcomes.

Conclusion:

Compared with radiocephalic shunts, brachiocephalic shunts demonstrated superior primary patency rates, suggesting that they may be preferable options for long-term hemodialysis access in the studied population. These findings emphasize the need for individualized patient management and careful postoperative monitoring, particularly in resource-limited settings such as Yemen, to optimize AV shunt outcomes.

Vascular Medicine

Arteriovenous shunts

Hemodialysis

Primary patency

Brachiocephalic shunts

Radiocephalic shunts

Yemen

Compared with other vascular access options, arteriovenous fistulas (AVFs) are the preferred method for long-term hemodialysis access because of their superior patency rates and lower risk of complications, such as grafts and central venous catheters [1]. In regions such as Yemen, where healthcare resources are limited, the importance of effective and durable vascular access is paramount, as the burden of end-stage renal disease (ESRD) continues to increase. Yemen faces a growing incidence of ESRD, with cases rising from an estimated 93 per million people in 2006 to over 5200 patients on maintenance dialysis by 2019 [2]. This rapid increase places significant strain on an already overburdened healthcare system, highlighting the urgent need for reliable and sustainable access to dialysis.

Despite the critical role of AVFs in ensuring successful hemodialysis, data from low- and middle-income countries, including Yemen, on AVF outcomes are lacking [3]. The absence of such data hinders the development of evidence-based strategies to improve patient outcomes, particularly in healthcare systems that are already stretched to their limits. Existing studies have focused primarily on outcomes in high-resource settings, where factors such as patient selection, surgical expertise, and postoperative care differ significantly from those in Yemen. This gap in the literature underscores the need for region-specific research to inform local clinical practices and healthcare policies.

In the Yemeni context, brachiocephalic shunts are the most commonly used AVFs, followed by radiocephalic and brachiobasilic shunts [4]. These findings are consistent with international practices, although the specific preferences may vary depending on local expertise and patient characteristics [5]. However, the primary patency rates and the factors influencing these outcomes in Yemeni patients remain poorly understood. Accurate preoperative assessment and careful selection of the AVF site are essential for optimizing the success of these procedures and minimizing complications [6].

This study addresses the pressing need for data on AVF outcomes in Yemeni hemodialysis patients. By evaluating the primary success rates and identifying factors that influence AVF patency at Al-Thawra Modern General Hospital in Sana’a, this research provides critical insights that will inform clinical practice and healthcare policy. The findings from this study are expected to not only fill a significant gap in the literature but also guide efforts to enhance dialysis care in resource-limited settings such as Yemen, ultimately contributing to improved patient outcomes and reduced healthcare burdens.

Study design

This was a prospective observational study conducted at Al-Thawra Modern General Hospital in Sana’a, Yemen, over a 28-month period from April 2021 to August 2023. The primary aim was to evaluate the primary patency success rates of arteriovenous (AV) shunts in patients with chronic renal failure undergoing hemodialysis. Additionally, this study sought to identify patient- and shunt-related factors that influence patency outcomes.

Study population

The study population consisted of 163 patients diagnosed with chronic renal failure who required AV shunt creation for hemodialysis. The inclusion criterion was patients on maintenance hemodialysis who required AV shunt placement and provided informed consent. Patients who refused participation, were lost to follow-up, or had peripheral vascular disease or extensive arterial occlusive disease were excluded to ensure accurate assessment of AV shunt outcomes.

Preoperative assessment

All patients underwent a comprehensive preoperative evaluation, including physical examinations to assess arterial pulses and venous outflow in the upper extremities. Doppler ultrasonography was routinely performed to evaluate the suitability of the radial or brachial arteries for vascular access creation, with measurements including artery diameter, systolic flow rates, and the resistive index. These assessments are crucial for predicting postoperative success and optimizing the selection of the AVF site.

Surgical Procedure

AV shunts were created under moderate sedation with local anesthesia (0.5% lidocaine). The surgical procedure varied according to the type of shunt: a transverse incision was made at or below the elbow crease for brachiocephalic shunts, and a longitudinal incision was made at the wrist for radiocephalic shunts. The cephalic vein was dissected, flushed with heparinized saline, and anastomosed to the artery in an end-to-side fashion via nontraumatic vascular clamps. Intraoperative success was confirmed through the presence of a thrill over the fistula or with a nondirectional Doppler probe, ensuring immediate patency and functional success.

Postoperative assessment and follow-up

Postoperative evaluations were conducted on the first and seventh days after surgery, with follow-up continuing for a maximum of eight months. These evaluations included physical examinations to check for thrill and pulse at the fistula site, as well as Doppler ultrasonography to measure the fistula size, velocity, volume flow, and resistive index of the distal artery. Postoperative values were compared with preoperative values to determine shunt functionality and detect any early complications.

Data collection

Data were collected via a structured questionnaire that covered demographic information, clinical data, and outcome measures. The demographic data included age, sex, and medical history, whereas the clinical data focused on the duration of hemodialysis, previous AV shunt placements, comorbidities, and details of the surgical procedure. The outcome measures included primary patency rates, postoperative complications, and reintervention rates to provide a comprehensive assessment of AV shunt success and durability.

Statistical analysis

The data were processed via SPSS version 25. Descriptive statistics were employed to summarize patient demographics and clinical characteristics, with categorical variables presented as frequencies and percentages and continuous variables summarized using means and standard deviations. Associations between categorical variables were assessed via the chi-square test, whereas multiple response analysis was applied to capture the complexity of patient outcomes in this diverse population. Statistical significance was set at p < 0.05.

Ethical considerations

The study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. Ethical approval for this study was obtained from the Ethical Committee of Al-Thawra Modern General Hospital, with Institutional Review Board (IRB) approval number TMGH/IRB/2021/022, which was granted on March 15, 2021. All participants provided informed consent after being fully informed of the study’s objectives, procedures, potential risks, and benefits. The participants were assured of the voluntary nature of their involvement and the confidentiality of their personal information.

Demographics and Baseline Characteristics

The study included 163 patients with chronic renal failure who underwent AV shunt creation for hemodialysis. The median age was 43.12 years, with a range from 9–80 years. The majority of patients (33.7%) were aged between 41 and 60 years, and 55.8% of the population was female. Common comorbidities included diabetes mellitus (50.3%) and hypertension (34.4%). A significant portion of the patients (68.1%) received their first AV shunt, whereas 31.9% had a history of previous vascular access, indicating a more complex clinical background for this subset of patients (Table 1).

Table 1

Demographics and baseline characteristics of the patients (n = 163)
Characteristic	Frequency (n = 163)	Percentage (%)
Age (years)
Median, IQR	43.12 (9–80)	-
Mean ± SD	43.12 ± 15.46	-
Age group (years)
9–20	22	13.5
21–40	49	30.1
41–60	55	33.7
61–80	37	22.7
Gender
Male	72	44.2
Female	91	55.8
Comorbidities
Diabetes Mellitus	82	50.3
Hypertension	56	34.4
Coronary Artery Disease	24	14.7
Peripheral Vascular Disease	18	11.0
Chronic Obstructive Pulmonary Disease	12	7.4
History of previous vascular acess
Yes	111	68
No	52	32

AV Shunt Characteristics

The most common site for AV shunt creation was the left cubital fossa (49.7%), followed by the left wrist (29.1%). Brachiocephalic shunts were the most frequently performed shunts (61.3%), followed by radiocephalic shunts (32%) and brachiobasilic shunts (6.7%). These findings are consistent with the established preference for brachiocephalic shunts in this population because of their relatively high patency rates and suitability for long-term dialysis access (Table 2).

Table 2

AV Shunt Characteristics (n = 163)
Characteristics	Frequency	Percentage (%)
Shunt Location
Left Cubital Fossa	81	49.7
Left Wrist	47	29.1
Right Cubital Fossa	25	15.1
Right Wrist	10	6.1
Shunt Type
Brachiocephalic	100	61.3
Radiocephalic	52	32
Brachiobasilic	11	6.7

Complications and Outcomes

Approximately 25% of the patients experienced complications during the study period. The most common complication was pseudoaneurysm formation (6.1%), followed by infection at the fistula site (4.9%), venous hypertension (4.9%), thrombosis (3.7%), and aneurysm rupture (3.1%). These complications were managed conservatively or surgically, depending on their severity and impact on shunt functionality (Table 3).

Table 3

Complications associated with AV Shunts among Study Participants (n = 163)
Complication	Frequency	Percentage (%)
Pseudoaneurysm	10	6.1
Infection at Fistula Site	8	4.9
Venous Hypertension	8	4.9
Thrombosis	6	3.7
Aneurysm Rupture	5	3.1

Primary Patency Outcomes

At the 8-month follow-up, 87.7% of the shunts (143 out of 163) remained patent, whereas 12.3% (20 out of 163) were not patent. Among the 20 nonpatent shunts, 80% underwent revision, and 20% required the creation of a new shunt. When the distribution of patent shunts by type was examined, the majority were brachiocephalic (65%), followed by radiocephalic (29%) and brachiobasilic (6.3%). These results highlight the superior performance of brachiocephalic shunts in maintaining long-term functionality compared with other shunt types (Table 4).

Table 4

Primary Shunt Patency and Reintervention Outcomes (n = 163)
Variable	Frequency	Percentage (%)
Primary Shunt Patency
Patent	143	87.7%
Not Patent	20	12.3%
Reintervention Among Non-Patent Shunts (n = 20)
Shunt Revision	16	80.0%
New Shunt Creation	4	20.0%
Distribution of Patent Shunts by Shunt Type (n = 143)
Brachiocephalic	93	65.0%
Radiocephalic	41	29.0%
Brachiobasilic	9	6.3%

Overall, the primary patency rate across all shunt types was 87.7%. Brachiocephalic shunts had the highest patency rate (93.0%), followed by brachiobasilic shunts (81.8%) and radiocephalic shunts (67.3%). These findings underscore the superior outcomes associated with brachiocephalic shunts, making them the preferable choice for long-term hemodialysis access in this patient population (Table 5).

Table 5

Patency Rates by Shunt Type
Shunt Type	Patent Shunt (n = 143)	Total Shunt (n = 163)	Patency Rate (%)
Overall Primary Patency	143	163	87.7%
Brachiocephalic	93	100	93.0%
Brachiobasilic	9	11	81.8%
Radiocephalic	35	52	67.3%

Factors influencing primary patience

At the 8-month follow-up, primary patency rates were analyzed across various factors, including age, comorbidities, and shunt type. The 41–60 years age group had the highest proportion of patent shunts (34.3%), whereas the 21–40 and 61–80 years age groups also presented relatively high patent rates (30.1% and 22.4%, respectively). Comorbidities such as diabetes and hypertension were common among patients with patent shunts, representing 49.7% and 33.6% of this group, respectively. However, the most significant factor influencing the patency rate was the type of shunt used. Brachiocephalic shunts had the highest patency rate, with 65.0% of these shunts remaining patent, whereas radiocephalic shunts had a higher failure rate, with 55.0% failing (p = 0.02). This finding indicates that shunt type is a critical determinant of long-term patency outcomes (Table 6).

Table 6

Factors influencing primary patience rates at the 8-month follow-up
Factor	Patent (n = 143)	Failed (n = 20)	p value
Age Group (years)			0.15
9–20	19 (13.3%)	3 (15.0%)
21–40	43 (30.1%)	6 (30.0%)
41–60	49 (34.3%)	6 (30.0%)
61–80	32 (22.4%)	5 (25.0%)
Comorbidities			0.22
Diabetes Mellitus	71 (49.7%)	11 (55.0%)
Hypertension	48 (33.6%)	8 (40.0%)
Coronary Artery Disease	20 (14.0%)	4 (20.0%)
Peripheral Vascular Disease	15 (10.5%)	3 (15.0%)
COPD	10 (7.0%)	2 (10.0%)
Shunt Type			0.02*
Brachiocephalic	93 (65.0%)	7 (35.0%)
Brachiobasilic	9 (6.3%)	2 (10.0%)
Radiocephalic	41 (28.7%)	11 (55.0%)

*Note: The p value of 0.02 indicates a statistically significant difference in patency rates among the different shunt types.

This prospective study aimed to evaluate the primary patency success of arteriovenous (AV) shunts in hemodialysis patients at Al-Thawra Modern General Hospital. Our findings demonstrated a high primary patency rate of 87.7% at the 8-month follow-up. Notably, brachiocephalic shunts presented the highest patency rate (93.0%), significantly outperforming radiocephalic shunts, which presented a patency rate of 67.3% (p = 0.02). These results suggest that brachiocephalic shunts should be considered the preferred option for long-term hemodialysis access in this population, particularly in resource-limited settings.

The high primary patency rate observed in our study aligns with the literature, which underscores the superiority of brachiocephalic AV fistulas in providing long-term hemodialysis access. For example, Nguyen et al. (2007) reported that brachiocephalic fistulas generally outperform radiocephalic fistulas in terms of both maturation time and primary patency, with brachiocephalic fistulas showing a primary patency of 16 ± 7 months compared with 13 ± 4 months for radiocephalic fistulas [7]. These findings are consistent with our results, where brachiocephalic shunts demonstrated superior patency rates.

However, it is essential to recognize the potential complications associated with brachiocephalic fistulas. Ateş et al. (2006) reported a higher incidence of complications such as edema and the steal phenomenon with brachiocephalic fistulas, highlighting the need for careful patient selection and monitoring to balance the benefits of higher patency rates against these risks [8]. In our study, 25% of patients experienced complications, with pseudoaneurysm formation being the most common (6.1%), followed by infection at the fistula site (4.9%), venous hypertension (4.9%), and thrombosis (3.7%). These complications, while manageable, underscore the importance of postoperative monitoring and timely intervention to preserve shunt functionality.

Our findings also suggest that patient-related factors, including comorbidities such as diabetes, play a significant role in shunt outcomes. Fitzgerald et al. (2004) reported that comorbidities such as diabetes can adversely affect outcomes, leading to longer maturation times and lower patency rates [9]. In our study, nearly half of the patients with patent shunts had diabetes (49.7%), indicating that while diabetes may impact patency, brachiocephalic shunts may offer a more resilient option in this population. This highlights the need for individualized treatment planning to optimize AV shunt success in patients with complex medical histories.

In addition to shunt type, our study identified several factors influencing primary patency rates. Patient age was another significant factor, with the 41–60 age group having the highest proportion of patent shunts (34.3%). This finding aligns with previous studies suggesting that middle-aged patients may benefit more from AV shunt placement [10]. Similarly, Smith et al. (2012) reported that increasing age, diabetes, and peripheral vascular disease negatively impact AV fistula patency [11]. The presence of these common comorbidities in our study population emphasizes the importance of tailored patient selection and management strategies.

One of the strengths of our study is its prospective design, which allowed for systematic data collection and follow-up, ensuring the reliability of the observed outcomes. Additionally, the relatively large sample size for a single-center study enhances the generalizability of our findings within similar resource-limited settings. However, our study is not without limitations. The single-center design may limit the generalizability of our results to other settings with different patient populations or healthcare infrastructures. Furthermore, the follow-up period of 8 months, while sufficient for assessing early patency, may not capture long-term outcomes, which are crucial for understanding the durability of AV shunts. Further studies with longer follow-up periods and multicenter designs are recommended to validate our findings and explore the factors influencing long-term patency.

The high patency rates observed in our study suggest that brachiocephalic shunts should be prioritized in patients undergoing hemodialysis, particularly in resource-limited settings such as Yemen. The identification of shunt type as a critical determinant of patency outcomes highlights the need for careful preoperative planning and individualized patient management to optimize surgical outcomes. Given the significant complication rate, our findings underscore the importance of postoperative monitoring and early intervention to address complications, particularly in settings where access to specialized vascular care may be limited. Proper care during access insertion and meticulous management during dialysis can help reduce complications, as highlighted by Connolly et al. (1984) [12] These insights could inform healthcare policies aimed at improving the quality of hemodialysis care in Yemen and similar contexts, potentially reducing the burden of end-stage renal disease and improving patient outcomes.

In conclusion, our study demonstrated that brachiocephalic shunts provide superior primary patency rates compared with radiocephalic shunts in hemodialysis patients, making them the preferred option for long-term vascular access, especially in resource-limited settings such as Yemen. The high primary patency rate of 87.7% observed in this study underscores the effectiveness of AV shunts in maintaining long-term functionality, particularly when brachiocephalic shunts are employed.

However, the significant complication rate observed, particularly the formation of pseudoaneurysms and other vascular complications, highlights the necessity for diligent postoperative monitoring and timely intervention. These findings emphasize the importance of individualized patient management, considering factors such as age, comorbidities, and shunt type, to optimize outcomes and minimize complications.

Given the challenges faced by healthcare systems in low- and middle-income countries, our study provides valuable insights that could inform local clinical practices and healthcare policies. Prioritizing brachiocephalic shunts and implementing rigorous follow-up protocols may increase the success of hemodialysis programmes in similar contexts.

Future studies with longer follow-up periods and multicenter involvement are recommended to validate these findings and further explore the long-term durability and outcomes of AV shunts in diverse patient populations. By addressing these gaps, future research can contribute to improving the quality of dialysis care and ultimately reduce the burden of end-stage renal disease in resource-limited settings.

AVF

arteriovenous fistula

arteriovenous

COPD

Chronic obstructive pulmonary disease

ESRD

End-stage renal disease

IRB

Institutional Review Board

Standard deviation

Ethical Approval and Consent to Participate

The study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. Ethical approval for this study was obtained from the Ethical Committee of Al-Thawra Modern General Hospital, with the Institutional Review Board (IRB) approval number TMGH/IRB/2021/022 granted on March 15, 2021. All participants provided informed consent after being fully informed of the study’s objectives, procedures, potential risks, and benefits. The participants were assured of the voluntary nature of their involvement and the confidentiality of their personal information.

Consent for Publication

Not applicable.

Competing Interests

The authors declare that they have no competing interests.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Authors' contributions

N.Y.A. contributed to the study conception and design; data collection, analysis, and interpretation; and drafted the manuscript. Z.A. participated in data collection, analysis, and manuscript revision. G.A. and H.M.J. provided critical revision of the manuscript for important intellectual content. All the authors have read and approved the final manuscript, ensuring that each has contributed significantly to the work and agrees with its submission.

Acknowledgments

The authors would like to thank the staff at Al-Thawra Modern General Hospital for their support and assistance in conducting this study. Special thanks to the patients who participated in this study.

Availability of Data and Materials

The datasets used and analyzed during the current study are available from the corresponding author upon reasonable request.

Bylsma LC, Gage SM, Reichert H, Dahl SLM, Lawson JH (2017) Arteriovenous Fistulae for Haemodialysis: A Systematic Review and Meta-analysis of Efficacy and Safety Outcomes. Eur J Vasc Endovasc Surg 54:513–522. 10.1016/j.ejvs.2017.06.024
Alkubati SA, Al-Sayaghi KM, Salameh B, Halboup AM, Ahmed WAM, Alkuwaisi MJ, Zoromba MA (2024) Prevalence of Depression and Its Associated Factors Among Hemodialysis Patients in Hodeida City, Yemen. J Multidiscip Healthc 17:689–699. 10.2147/JMDH.S452935
Htay H, Bello AK, Levin A et al (2021) Hemodialysis Use and Practice Patterns: An International Survey Study. Am J Kidney Dis 77:326–335e1. 10.1053/j.ajkd.2020.05.030
Al-Shameri I, KhudaBux G, Al-Ganadi A (2021) Prospective Evaluation of Factors Associated with Arteriovenous Fistula Primary Failure and Complications in Hemodialysis Patients: A Single Center-Study. Cardiol Vascular Res 5. 10.33425/2639-8486.1103
Tjang YS, Sumadi GJ (2018) Primary Patency Rate of Arteriovenous Fistula Created for Hemodialysis Patients: The Indonesian Experience. J Association Vascular Access 23:229–233. 10.1016/j.java.2018.07.001
Lok CE, Huber TS, Lee T et al (2020) KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update. Am J Kidney Dis 75:S1–164. 10.1053/j.ajkd.2019.12.001
Nguyen TH, Bui TD, Gordon IL, Wilson SE (2007) Functional Patency of Autogenous AV Fistulas for Hemodialysis. J Vasc Access 8:275–280. 10.1177/112972980700800410
Ates A, Özyazicioglu A, Yekeler I et al (2006) Primary and Secondary Patency Rates and Complications of Upper Extremity Arteriovenous Fistulae Created for Hemodialysis. Tohoku J Exp Med 210:91–97. 10.1620/tjem.210.91
Fitzgerald JT (2004) Outcomes of Upper Arm Arteriovenous Fistulas for Maintenance Hemodialysis Access. Arch Surg 139:201. 10.1001/archsurg.139.2.201
McGrogan D, Al Shakarchi J, Khawaja A, Nath J, Hodson J, Maxwell AP, Inston NG (2015) Arteriovenous fistula outcomes in the elderly. J Vasc Surg 62:1652–1657. 10.1016/j.jvs.2015.07.067
Smith GE, Gohil R, Chetter IC (2012) Factors affecting the patency of arteriovenous fistulas for dialysis access. J Vasc Surg 55:849–855. 10.1016/j.jvs.2011.07.095
Connolly JE (1984) Complications of Renal Dialysis Access Procedures. Arch Surg 119:1325. 10.1001/archsurg.1984.01390230091023

The authors declare no competing interests.

Download PDF

Version 1

posted

You are reading this latest preprint version

Primary Patency Success of Arteriovenous Shunts in Hemodialysis Patients: A 28-month Prospective Study at Al-Thawra Modern General Hospital, Yemen

Status:

Version 1

Abstract

Introduction

Materials and methods

Study design

Study population

Preoperative assessment

Surgical Procedure

Postoperative assessment and follow-up

Data collection

Statistical analysis

Ethical considerations

Results

Demographics and Baseline Characteristics

AV Shunt Characteristics

Complications and Outcomes

Primary Patency Outcomes

Factors influencing primary patience

Discussion

Conclusion

Abbreviations

Declarations

Competing Interests

Funding

Authors' contributions

Acknowledgments

Availability of Data and Materials

References

Additional Declarations

Status:

Version 1