Objective To investigate a modified angioplasty balloon catheter, which uses a novel balloon polymer to produce luminal moulds.

Design The catheter was tested in polyurethane phantoms of diameter 1.5 to 4.0 mm. Inflations were to 1.4 atmospheres for 20 seconds at 37°C. The moulds were viewed by reinflating the balloon to 0.34 atmospheres and quantified using macrophotography and caliper measurement.

Results Evidence of systematic error was found with lumen diameters ⩽ 2.0 mm, accuracy being 0.32 to 0.80 mm and precision 0.23 to 0.24 mm. However, between 2.5 and 4.0 mm the accuracy of measuring luminal diameters was 0.01 mm, the precision 0.06 mm, and the absolute mean error 0.05 mm. The results for percentage diameter stenosis were −1.15%, 0.86%, and 1.21%, and for lesion length they were 0.20, 0.60, and 0.41 mm, respectively.

Conclusions The prototype catheter shows a high degree of accuracy and precision in phantoms of diameter 2.5 to 4.0 mm—the range within which most interventional work is performed. Further work on this technique as a method of direct three dimensional moulding of the coronary artery lumen is warranted.