How do angioplasty balloons work: a computational study on balloon expansion forces

Aims: To investigate the impact of balloon inflation pressure and balloon diameter on the expansion forces exerted in a stenosed vessel (congenital heart disease applications) using computational models. Methods and results: A simplified three-dimensional model of a vessel with a cylindrical stenosis was created. Two low-compliance balloons with different inflation diameters (10 vs. 16 mm) were modelled. Finite element simulations of balloon expansions were performed. To dilate the stenosis from 4 to 10 mm lumen diameter, the large balloon needed less inflation pressure than the small balloon (0.55 vs. 1.00 MPa). Under these circumstances, the large balloon also achieved higher stresses at the stenotic vessel site (5.23 +/- 0.10 vs. 3.97 +/- 0.04 MPa, p<0.001). When using inflation pressures that led to equal surface stresses of both balloons, the large balloon could exert higher expansion forces onto the stenotic site, achieving higher stresses (5.18 +/- 0.09 vs. 3.38 +/- 0.01 MPa, p<0.001) and greater lumen diameter (9.73 vs. 8.68 mm). Conclusions: In a computerised model of balloon dilatation, balloon diameter had a greater impact on the expansion force than inflation pressure. This finding emphasises the importance of choosing an appropriate balloon diameter to achieve optimal haemodynamic outcomes.