Access survival amongst hemodialysis patients referred for preventive angiography and percutaneous transluminal angioplasty

Abstract

Background and objectives: Referring hemodialysis patients for elective access angiography and percutaneous transluminal angioplasty (PTA) is commonly done to prevent access failure, yet the effectiveness of this procedure remains unclear. DESIGN, SETTING, PARTICIPANTS, & MEASURES: An observational matched cohort analysis among 40,132 Medicare beneficiaries receiving hemodialysis with a fistula or graft was performed. Cox regression was used to determine whether access intervention was associated with improved 1-year access survival.

Results: Nonsurgical access intervention was found to be frequent at a rate of 20.9 procedures per 100 access years. In the 1-year period after intervention using angiography and PTA, the overall access failure rate was 53.7 per 100 access years in the intervention group and 49.6 in the nonintervention group (HR = 1.02; 95% CI, 0.96 to 1.08). Similar findings were also seen when the analysis was repeated in only fistulas (HR = 1.06; 95% CI, 0.98 to 1.15) and grafts (HR = 0.95; 95% CI, 0.86 to 1.05). In patients with a low intra-access flow rate (HR = 0.86; 95% CI, 0.75 to 0.99) or a new access (HR = 0.79; 95% CI, 0.71 to 0.89), angiography and PTA significantly increased access survival when compared with nonintervention (P for interaction was <0.0001). Angiography-PTA-related upper-extremity hematoma, vessel injury, or embolism-thrombosis occurred in 1.1% of all patients.

Conclusions: Access characteristics significantly modify the survival benefits of angiography and PTA intervention where the benefits of these interventions are most seen in newer accesses or accesses with insufficient flow.

Figure 1.

(A) One-year access survival after access intervention versus nonintervention. (B) The fistula failure rate was 54.8 per 100 access years in the intervention group and 47.8 in the nonintervention group (HR = 1.06; P = 0.13). (C) The graft failure rate was 51.7 per 100 access years in the intervention group and 52.7 in the nonintervention group (HR = 0.95; P = 0.32).

Figure 2.

(A) Hazard ratios for 1-year access survival in patients receiving access intervention versus nonintervention. Angiography and percutaneous transluminal angioplasty associated with significantly less benefit as the baseline intra-access flow rate increased. Similar diminishing access survival benefits were seen in older fistulas and grafts. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. (B) Hazard ratios for 1-year access survival in patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics.

Figure 2.

(A) Hazard ratios for 1-year access survival in patients receiving access intervention versus nonintervention. Angiography and percutaneous transluminal angioplasty associated with significantly less benefit as the baseline intra-access flow rate increased. Similar diminishing access survival benefits were seen in older fistulas and grafts. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. (B) Hazard ratios for 1-year access survival in patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics.

Figure 3.

(A) Hazard ratios (HRs) for 1-year access survival in FISTULA patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. (B) Hazard ratios for 1-year access survival in FISTULA patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics.

Figure 3.

(A) Hazard ratios (HRs) for 1-year access survival in FISTULA patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. (B) Hazard ratios for 1-year access survival in FISTULA patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics.

Figure 4.

(A) Hazard ratios (HRs) for 1-year access survival in GRAFT patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. (B) Hazard ratios (HRs) for 1-year access survival in GRAFT patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics.

Figure 4.

(A) Hazard ratios (HRs) for 1-year access survival in GRAFT patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. (B) Hazard ratios (HRs) for 1-year access survival in GRAFT patients receiving access intervention versus nonintervention. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics. Statistically significant survival outcomes by subgroup occurred when the P for interaction was <0.002. This P value was adjusted for multiple comparisons over 25 baseline access characteristics.