This is a prospective randomized study. All intervention will be carried out by experienced radiologists in the two study centres.
At least fifty (50) consecutive subjects meeting the eligibility criteria, scheduled for angiographic assessment (with a view to PTA if necessary), will be invited to participate in the study. Subjects who consent will undergo their procedure, which will be performed by a qualified interventional radiology doctor (IRD). Patients will be randomly allocated to each group. All previous Transonics measurements will be available to the treating IRD. A target flow rate will be pre-decided in all patients in consultation with the nephrology service.
- All patients will undergo a fistulogram, a routine interventional Xray exam where radiocontrast media (RCM) is injected under X ray control to identify narrowings within the vessels. Significant lesions will be identified based on this exam. If a lesion is believed to be significant, the patient will be assigned to either arm of the study. The details of the disease present will be recorded as location and percentage stenosis.
- In the control arm, an initial Transonic measurement pre-treatment will be performed. The interventionalist will select the most significant lesion based on angiographic appearances and treat this lesion, which may require use of multiple balloons for the same lesion. At this point a Transonics measurement will be taken - Measurement A. The results will not be revealed to the interventionalist, who will proceed with the procedure as per their standard practice. A Transonics measurement will be taken after treatment of each of the significant lesions identified at the start of the exam. A post-procedural Transonics measurement (Measurement X) will also be taken, again the interventionalist will blinded as to this result. The appearances on completion angiography will be recorded as percentage stenosis remaining.
- In the Transonics arm, a pre-treatment Transonic measurement will be done. The lesions will be treated. Once Measurement A is obtained, the interventionalist will only be informed if the target value has been reached or not, they will not be told the actual value. This will be repeated for the treatment of each subsequent lesion, with the interventionalist being informed if the target had been reached, whilst being blinded as to the Transonics result, until the target has been achieved. The interventionalist will not pursue further treatment, regardless of the Transonics measurement, if he deems it would pose a greater risk of complication to the patient, than his/her standard practice. The appearances on completion angiography will be recorded as percentage stenosis remaining.