Value of Doppler evaluation of physically abnormal fistula: hemodynamic guidelines and access outcomes

Abstract

Background/aims: The strategy of access care at out center involves the use of ultrasound (USG) in case of physical examination (PE) abnormality. USG determines the need of angiography. This study investigated the possible association between the need for percutaneous transluminal angioplasty (PTA) and hemodynamic parameters of USG. The study also assessed the effects of this monitoring strategy on outcomes in comparison with a historical control.

Methods: A retrospective study of the medical records of 127 patients (65 PTA, 62 non-PTA) was conducted. Data were analyzed using logistic regression analysis and receiver operating characteristic curve. Fistula outcomes and intervention rates were calculated and compared with 100 historic controls.

Results: Logistic regression analysis showed that brachial artery flow volume (FV) < 612.9 mL/min or brachial artery resistance index (RI) > 0.63 was independently associated with the need for PTA. This monitoring strategy showed an a reduction in thromboses (0.02 ± 0.11 events/arteriovenous fistula [AVF]-year vs. 0.07 ± 0.23 events/AVF-year, p = 0.046), reduction in central venous catheter placement (0.01 ± 0.05 events/AVF-year vs. 0.06 ± 0.22 events/AVF-year, p = 0.010), reduction in access loss (0.02 ± 0.13 events/AVF-year vs. 0.19 ± 0.34 events/AVF-year, p = 0.015), and increase in access selective repair (0.49 ± 0.66 events/AVF-year vs. 0.21 ± 0.69 events/AVF-year, p = 0.003), compared to historic control.

Conclusion: There was significant stenosis if brachial artery FV was < 612.9 mL/min or RI was > 0.63 for PE abnormality. These parameters should be used as markers for assessing PTA risk in hemodialysis patients. Addition of USG to determine the need of angiography after detection of PE abnormality leads to decreases in access thrombosis, catheter placement, and access loss despite increasing access intervention rates compared to clinical monitoring.

Keywords: Angioplasty; Ultrasonography, Doppler, color; Vascular access.

Figure 1.

Doppler f low volume and resistance index measurements.

Figure 2.

Angiographic diagnosis of stenosis (arrow); luminal diameter less than 50 % compared to nonstenotic area (arrowhead).

Figure 3.

Receiver operating characteristic (ROC) for brachial artery flow volume to discriminate percutaneous transluminal angioplasty. AUC, area under the ROC curve; CI, confidence interval.

Figure 4.

Receiver operating characteristic (ROC) for brachial artery resistance index to discriminate percutaneous transluminal angioplasty. AUC, area under the ROC curve; CI, confidence interval.

Figure 5.

Thrombosis free survival. The graphs show the unadjusted thrombosis free survival as of enrollment. The Kaplan-Meier analysis showed that thrombosis free survival was better in study group (black colored dashed line) than in historic control (red colored dashed line) but statistically nonsignificant.

Figure 6.

Primary survival. The graphs show the primary survival as of enrollment. The Kaplan-Meier analysis showed that primary access survival was significantly lower in study group (black colored dashed line) than in historic control (red colored dashed line) with the log rank test.

Figure 7.

Cumulative survival. The graphs show the cumulative survival as of enrollment. The Kaplan-Meier analysis showed that access survival was significantly better in study group (black colored dashed line) than in historic control (red colored dashed line) with the Breslow test.