HEMODIALYSIS VASCULAR ACCESS - VARIABLE THROMBUS-FREE SURVIVAL IN 3 SUBPOPULATIONS OF BLACK PATIENTS

Hemodialysis vascular access related problems account for most hospita lizations in chronic hemodialysis patients. Although some co-morbid ri sk factors for early fistula failures have been described, a great dea l of unknown exists as to why access survival is favorable in some pat ients. In this longitudinal study, fistulae patency and thrombosis epi sodes were monitored from placement date In three groups of end stage renal disease (ESRD) patients who have been on dialysis for greater th an or equal to 90 days. Thirty-six patients (29 male; 80%) with a mean age of 42 +/- 2 years were monitored. The groups consisted of eight p atients with biopsy-confirmed focal segmental glomerulosclerosis (FSGS ), 13 with acquired immunodeficiency syndrome related nephropathy (hum an immunodeficiency virus [HIV]), and 15 with hypertensive ESRD (hyper tensive nephrosclerosis [HTN]) who served as controls. Diabetics and p atients aged greater than or equal to 64 years were excluded. Twenty-f ive of 36 (69%) fistulae were prosthetic (AVG), while 11 (31%) were na tive (AVF). The FSGS group was more likely to have an AVG (87.5%), whi le 54% of the HIV group had an AVG. The thrombosis event rate was sign ificantly greater among the FSGS patients (3/patient-year) than the HI V (0.15/patient-year) and HTN (O.5/patient-year) patients (P < 0.0001 and P < 0.002, respectively). The mean thrombosis free duration for bo th AVG and AVF among the HIV and HTN groups were 318.5 +/- 17 days and 311.7 +/- 22.5 days, respectively. These were significantly greater t han in the FSGS group (26.5 +/- 7 days; P < 0.0001). The cumulative I- year patency rate for AVG among the HIV and HTN groups was 85% and 65% , respectively, while that of the FSGS group was 0%. Kaplan-Meier haza rd analysis showed that all groups were at risk of access thrombosis a s time progressed, but the FSGS group had the highest risk of access t hrombosis, which began from the date of placement and increased expone ntially with time. The increased thrombosis rate among the patients in the FSGS group correlated with their weight (R = 0.8, P = 0.003) and pre-ESRD 24-hour urinary protein excretion (R = 0.9, P = 0.001). The H IV status appeared to confer enhanced hemodialysis access survival. Th is may be related to the high rate of native fistulae placement and fa vorable vascular reactivity to shear stress. Accelerated atheroscleros is and small caliber vessels may be responsible for the poor fistulae outcome among the FSGS group. More studies will be necessary to furthe r explore these findings. (C) 1998 by the National Kidney Foundation, Inc.