Study design
This retrospective study was approved by the local ethics committee .
We reviewed all PTAs performed on upper limb dialysis access at our center in the period between August 2011 and March 2017.
These totalled 436 interventions out of which 114 were excluded from the analysis because these were abandoned during the procedure (VA considered failed/not salvageable or technical failure as unable to cross lesion). Angioplasty performed on the arterial side of the access were also excluded (n=2).
Sixteen PTA were excluded (two missing DSA data or report not available and 14 cases with ultrasound data not recorded).
Four PTA procedures were excluded because of the use of drug eluting balloons. Post-thrombectomy PTA were included (n=13).
Only patients followed up at the local hospital (Ninewells,
Dundee - UK) were included.
Twenty PTAs on 10 PTFE fistulas were excluded due to the well-established differences in patency profiles of AVGs requiring more frequent interventions to maintain patency.
A total of 138 fistulas were studied,
88 treated with standard balloon only and 50 with cutting balloon PTA.
A systematic US assessment was performed before the surgery,
the day after the procedure and again at 6,
12,
24 and 52 weeks.
When abnormal results were observed,
fistulography was performed.
On the basis of clinical,
hemodynamic or US changes,
patients were referred to our angiography unit for diagnostic fistulography and treatment as appropriate.
Technique
Written consent was obtained from all patients before the procedure.
The intervention was performed under local anesthesia,
with sedation when required,
and the use of vascular sheaths .
The direction of the access was chosen according to the location of the stenosis previously defined on US (retrograde for perianastomotic stenosis; antegrade for proximal venous,
mid/upper-arm,
and cephalic arch stenosis).
Arterial access was used only for imaging in complex stenoses in XX cases.
After the stenosis had been crossed using a combination of guidewires and catheters depending on its morphology,
a 4 or 5 Fr sheath for standard balloon and a 7 Fr sheath for cutting balloon was inserted.
Both antegrade and retrograde access were performed if needed (ex: presence of multiple stenoses in different locations).
All cases had heparin administered during procedure – this ranged between 3000 and 5000 IU at the dependent on the individual Radiologist/practitioner.
Different sizes of balloon were used,
ranging from 4 to 12 mm,
depending on the stenosis and on the operator’s discretion,
usually 10%– 15% oversized compared with the adjacent normal vein.
With the use of an inflation device with a pressure gauge,
the angioplasty balloon was gradually inflated until the stenosis was eliminated,
reaching and passing the rated burst pressure (rbp) if necessary.
Standard balloon was used as a first attempt.
Thrombosed fistulae were not excluded.
Following thrombolysis (Arrow-Trerotola Percutaneous Thrombolytic Device) ,
if an underlying stenosis was discovered a standard or cutting balloon angioplasty was performed.
The decision as to whether the fistula was salvageable was based on standard criteria,
which included the duration of thrombosis,
amount of thrombus,
and presence or absence of aneurysmal dilatation of the fistula.
If the appearances were satisfactory the sheath was removed after the application of a hemostatic purse-string suture
Data recorded and definitions
The target lesion and the presence of any eventual further stenoses were evaluated at diagnostic fistulography.
The diameter of the vessel before and after the venoplasty was recorded and compared to the diameter of the balloon to define the recoil of the stenosis after the procedure.
Anatomic measurements were made with the use of a calibrated reference marker.
Patency was defined using standardised published criteria (13).
This study aimed also to assess the procedural success (defined as a residual stenosis ≤50%),
number of repeat interventions on the same vascular access and degree of residual stenosis of the vessel in comparison with the inflating balloon diameter (stenosis recoil).
Statistical Analysis
Comparisons were made between the two groups with respect to demographic,
fistula,
and intervention characteristics. Non-normally distributed continuous variables were compared by using the Mann-Whitney U and Pearson chi-Square tests.
Statistical analysis of the postintervention primary and secondaty patency patency were performed with the Kaplan Meier method.
A P value of less than .05 was indicative of statistical significance.
All statistical analyses were performed with SPSS statistical software (IBM SPSS Statistics,
version 20.0.0).