Clinical Value of Intraoperative Transit-Time Flow Measurement for Autogenous Radiocephalic Arteriovenous Fistula in Patients with Chronic Kidney Disease

Intraoperative transit time flow measurement predicts maturation of radiocephalic arteriovenous fistulas

OBJECTIVE

The arteriovenous fistula (AVF) is the first choice for gaining vascular access for hemodialysis. However, 20% to 50% of AVFs fail within 4 months after creation. Although demographic risk factors have been described, there is little evidence on the intraoperative predictors of AVF maturation failure. The aim of this study was to assess the predictive value of intraoperative transit time flow measurements (TTFMs) on AVF maturation failure.

METHODS

In this retrospective cohort study, intraoperative blood flow, measured using TTFM, was compared with AVF maturation after 6 weeks in 55 patients. Owing to its significantly higher prevalence and risk of nonmaturation, the radiocephalic AVF (RCAVF) was the main focus of this study. A recommended cutoff point for high vs low intraoperative blood flow was determined for RCAVFs, using a receiver operating characteristic curve.

RESULTS

The average intraoperative blood flow in RCAVFs was 156 mL/min. Patients with an intraoperative blood flow equal or lower than the determined cutoff point of 160 mL/min, showed a 3.03 times increased risk of AVF maturation failure after 6 weeks, compared with patients with a higher intraoperative blood flow (P < .001).

CONCLUSIONS

The intraoperative blood flow in RCAVFs measured by TTFM provides an adequate means of predicting AVF nonmaturation 6 weeks after surgery. For RCAVFs, a cutoff point for intraoperative blood flow of 160 mL/min is recommended for maximum sensitivity and specificity to predict AVF maturation failure after 6 weeks.

New hemodynamic variables as predictors of arteriovenous fistula maturation

INTRODUCTION

Failure to mature of native arteriovenous fistula (AVF) assessed by image is not well documented.

METHODS

The aim of this study is to evaluate AVF maturation by Doppler ultrasound within 6 weeks after surgery and check for new hemodynamic variables as prognostic factors.

RESULTS

A total of 155 native AVFs were created in 3 years. Median age of patients was 71 years (60;79), with male gender predominance of 59.4% (n = 92). Diabetes was present in 60.6% (n = 94). AVF was created in distal forearm in 49.7% (n = 77). Un-assisted and overall maturation was of 67.1% (n = 104) and 83.9% (n = 130), respectively. Failure to mature occurred in 21.3% (n = 33) and primary failure in 9.7% (n = 15). In univariate analysis, preoperative variables such as diameter of artery (3.5 vs. 2.2 mm; p < 0.001) and pulsatility index (7.9 vs. 6.6; p = 0.055) were associated with failure to mature of AVF. Postoperative variables as Qa (994 vs. 401 mL/min; p < 0.001), resistance index (0.52 vs. 0.63; p < 0.001), pulsatility index (0.74 vs. 1.21; p < 0.001), and acceleration time (0.17 vs. 0.12; p < 0.001) also predicted an unfunctional AVF. Spearman correlation coefficient (r) was good for resistance index (-0.628) and pulsatility index (-0.707) in comparison with blood flow (Qa). In multivariate analysis, postoperative pulsatility index was an independent predictor of AVF dysfunction (OR: 16.5; p < 0.001).

CONCLUSIONS

Failure to mature was of 21.3%. Pulsatility index could be an important tool as new hemodynamic variable to predict failure to mature of native AVF.

Programmatic change leads to enhanced resource utilization and efficiency in port placement

BACKGROUND

Central venous port (CVP) placement is performed by a variety of surgeons in different subspecialties, and our previous work suggests that individual surgeons-regardless of training-are the strongest predictor of outcomes. We sought to prospectively evaluate a programmatic shift toward a resource-conscious, patient-focused algorithm for this common and simple surgical procedure.

MATERIALS AND METHODS

After implementation of a systems-level program for efficient CVP placement, 78 CVPs were placed by a single surgeon. Primary outcomes were procedure time, total operating room (OR) time, total facility time, and procedure-related complications. These prospective data were compared with retrospective cohorts of surgically placed and interventional radiology-placed CVP. Demographic data were analyzed by chi-square analysis, whereas time data were analyzed by the Wilcoxon rank-sum test.

RESULTS

The programmatic delivery (prospective) set showed significantly shorter procedural (median 16 min versus 26-40, P <0.05), OR times (median 36 min versus 46-70, P <0.05), and facility times (median 235 min versus 299-319, P <0.05) except for the interventional radiology facility time (median 187 versus 235, P <0.05). The range of OR time savings with the prospective versus comparison groups was 10-34 min, representing 22%-49% reductions in OR time (P <0.05). Complication rates were not significantly different (P = 0.13).

CONCLUSIONS

Through a programmatic change emphasizing efficiency and patient-centered outcomes, procedural/OR/facility time can be reduced greatly without changing complication rates. These data provide compelling evidence that common and ostensibly simple operative procedures can be substantially improved upon with thoughtful, data-driven systems-level enhancements.