External beam irradiation as an adjunctive treatment in failing dialysis shunts

To evaluate the utility of low-dose irradiation as adjunctive treatment for failing dialysis shunts related to stenoses.

Thirty-one patients with 41 lesions in their dialysis shunts were successfully enrolled for this study. After imaging of the shunt and calculation of venous stenoses, each patient was randomized into one of two segments of the protocol: (i) angioplasty and/or stent placement alone, and (ii) angioplasty and/or stent placement followed by external beam irradiation. All patients with significant venous stenoses (> or =50%) were treated with appropriately sized PTA (percutaneous transluminal angioplasty) and Wallstents. Patients randomized to the external irradiation segment underwent localized irradiation via a Theratron cobalt unit of 7 Gy 0-24 hours and 24-48 hours after intervention. Those patients randomized to the control group received no additional treatment. Clinical follow-up included resumption of successful dialysis with appropriate hemodynamic parameters. Two follow-up shunt images were obtained, follow-up 1 (fu-1) from 90 to 179 days and follow-up 2 (fu-2) from 180 to 365 days. Percentages of significant recurrent stenoses, defined as greater than 50%, were recorded and re-treated as needed.

Sixteen of the 31 patients underwent external beam irradiation. There were 21 lesions in the test group that underwent irradiation after intervention, and 20 lesions were treated with intervention alone. There were seven native arteriovenous fistulas and 24 Gore-tex grafts. All stenoses were either venous outflow stenoses (68%) or central stenoses (32%). The authors utilized chi2 analysis to compare restenoses rates between the control and irradiated groups at fu-1 (P<.99) and fu-2 (P<.10).

Although the results show that external beam irradiation has minimal effects on the restenoses of dialysis grafts when used in conjunction with PTA and stent placement, further studies with a larger, more homogenous population are needed to assess the trend of improving patency rates after external beam irradiation.