Here is the design of a clinical trial:

Official Title: SIroliMus Coated angioPlasty Versus Plain Balloon Angioplasty in the tREatment of dialySis acceSs dysfunctION (IMPRESSION)

Included conditions:
- End Stage Renal Failure on Dialysis
- Arteriovenous Graft Occlusion

Study Armgroups:
- {'label': 'Sirolimus coated balloon', 'type': 'EXPERIMENTAL', 'description': 'The trial product is MagicTouch sirolimus drug coated balloon (Concept Medical). Sirolimus will be transferred from the balloon to the vessel wall by inflating the sirolimus coated balloons at 2 minutes at rated burst pressure (typically 12 to 14ATM). All the lesions within the dialysis circuit with sirolimus coated balloon.', 'interventionNames': ['Device: Sirolimus coated balloon']}
- {'label': 'Plain balloon', 'type': 'PLACEBO_COMPARATOR', 'description': 'The plain balloon or placebo will not be coated. The plain balloon will be inflated at 2 minutes at rated burst pressure (typically 12 to 14 ATM). Plain balloon will be applied to all the narrowed segment of the dialysis circuit', 'interventionNames': ['Device: Plain balloon']}

Interventions:
- {'type': 'DEVICE', 'name': 'Sirolimus coated balloon', 'description': 'Sirolimus has a high transfer rate to the vessel wall and effectively inhibit neointimal hyperplasia in the porcine coronary model. In coronary artery interventions, preliminary clinical studies using sirolimus coated balloon have shown excellent procedural and 6 month patency. The effectiveness of sirolimus coated balloon in patients with dialysis access dysfunction has been shown in a small pilot study in the salvage of thrombosed arteriovenous graft.\n\nWhen compared to Paclitaxel, sirolimus is cytostatic in its mode of action with a high margin of safety.', 'armGroupLabels': ['Sirolimus coated balloon']}
- {'type': 'DEVICE', 'name': 'Plain balloon', 'description': 'Plain balloon angioplasty is the current standard therapy to treat stenosis in dialysis access. However, the mid and long term patency of plain balloon angioplasty in patients with end stage renal disease is poor. The average primary patency is around 40 to 50 percent at 1 year and multiple repeated angioplasty is required to maintain the patency of the vascular access.', 'armGroupLabels': ['Plain balloon']}

Primary Outcomes:
- {'measure': 'Primary patency of the AVF at 6 months', 'description': 'This is measured by the percentage of patients whose AVF remain patent at 6 months after the procedure', 'timeFrame': '6 months'}

Please estimate the sample size based on the assumption: 
A dropout rate of 10%, 80% power, and a significance level to detect a difference between the two groups at 6 months.
Sample size calculation
        We assume that the SCB will have a similar effectiveness as the PCB based on a previous meta-analysis of published RCT, the 6-month target lesion primary patency 73.7% with PCB vs. 55.2% with plain balloon angioplasty. Considering a dropout rate of 10%, a sample size of 170 patients randomized into a 1:1 ratio will have 80% power to detect a difference between the two groups at 6 months.