CUMULATIVE PATENCY RATES OF VASCULAR ACCESSES IN PATIENTS ON MAINTENANCE HEMODIALYSIS

1. CUMULATIVE PATENCY RATES OF VASCULAR ACCESSES IN PATIENTS ON MAINTENANCE HEMODIALYSIS Vishal B Parekh, MD, Madhavi Mandala, MD, Abhinav Singh, MD, Prashant Mudireddy, MD, Harsha Allu, MD, Sheel Dahal, MD, Paul Christos, MS, Ahmed Abdurhman, MD DEPARTMENT OF MEDICINE, ST. BARNABAS HOSPITAL, NY BACKGROUND Hemodialysis (HD) vascular access failure is a major cause of morbidity and mortality for patients on HD. It is encouraged by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative [K/DOQI] that HD centers examine the patency rates of vascular accesses as part of their Vascular Access Quality Assurance and Continuous Quality Improvement programs. According to the K/DOQI Update in 2000, Cumulative Patency Rate of ArterioVenous Grafts (AVGs) for a period of one year was determined to be 70%, while that for AV Fistulas (AVF) was not established.1 Numerous studies have reported 1-year patency rates of grafts between 63% and 90%.2,3 One report described an overall average patency rate of 70%.4,5 OBJECTIVE Vascular accesses are established at St. Barnabas Hospital for patients undergoing HD at Fordham HD Center. We wanted to determine the cumulative patency of all the established vascular accesses over a period of one year after their establishment at St. Barnabas Hospital, irrespective of the measures utilized to maintain their patency. The null and alternative hypotheses for AVGs were as follows: H0: One-year patency proportion is equal 70%; HA: One-year patency proportion is not equal to 70%. DESIGN Retrospective chart review was performed. Patients who had vascular accesses established at St. Barnabas Hospital and those accesses were being utilized for HD at Fordham HD Center were included in the study. Patients who were on HD via use of catheters at the Fordham HD Center were excluded from the study. INCLUSION CRITERIA • Review of patient records following vascular access placement in or before June 2001, until a period of three years after placement of access. • 1. Patients who receive new accesses due to malfunctioning of the prior access would be considered as individual new subjects. • 2. Age, Gender, presence of co-morbid conditions like Diabetes, Hypertension, HIV infection will also be looked upon as risk factors. • 3. Our proposed study would include patients, both men and women, above the age of 18, belonging to all castes and ethnic populations. STATISTICAL ANALYSIS: The data was analyzed by SPSS software. We used a one-sample z-test for a binomial proportion (which compares the proportion observed in our sample to the expected national proportion). Results: Fig 1: We observed that 71.14% of AVGs remained patent at the period of 1 year comparable to the expected standards by K/DOQI Update of 2000. The p-value from this test was 0.77, which indicates that the two numbers do not statistically differ (ie. 71.1% patency at one year is no different from the national number of 70%). Based on this test, we do not reject the null hypothesis (which means that the proportions do not differ). The 95% confidence interval around the proportion observed in our study is (64%, 79%). Because the confidence interval includes the 70% national proportion, this is why we do not reject the null hypothesis and we conclude that the proportions do not differ. CONCLUSIONS: 71.14% of AVGs were found to remain patent at the period of 1 year comparable to the expected standards by K/DOQI Update of 2000. Females had longer patency of vascular accesses than males. Further studies can be then be directed towards determination of factors involved in maintaining vascular access patency. Comparision of patency of AVG & AVF amongst Males vs Females REFERENCES: • 1. National Kidney Foundation. K/DOQI Clinical Practice Guidelines for Vascular Access, 2000. Am J Kidney Dis 37:S137-S181, 2001 (suppl 1) Guideline 36 • 2. Clinical practice guidelines for hemodialysis adequacy. Am J Kidney Dis 2006 Jul;48(1 Suppl 1):S13-97. [364 references] • 3. Palder SB, Kirkman RL, Whittemore AD, Hakim RM, Lazarus JM, Tilney NL: Vascular access for hemodialysis. Patency rates and results of revision. Ann Surg 202:235-239, 19854. Raju S: PTFE grafts for hemodialysis access. Techniques for insertion and management of complications. Ann Surg 206:666-673, 1987 • 5. Mehta S: Statistical summary of clinical results of vascular access procedures for haemodialysis, in Sommer BG, Henry ML (eds): Vascular Access for Hemodialysis-II (ed 2). Chicago, IL, Gore, 1991, pp 145-157