Measurement of angioplasty lumen volume and wall compliance: a laboratory study

We have developed a device and technique for measuring the pressure-volume characteristics of an arterial segment from a standard angioplasty balloon, enabling us in this laboratory study to investigate the ability of the technique to measure changes in lumen volume and wall compliance. Percutaneous transluminal coronary angioplasty (PTCA) is a valuable clinical procedure for alleviating arterial stenosis, but the long-term success of the technique is less than ideal. The ability to monitor the effect of the balloon on the artery during inflations could lead to improvements in the technique. In this study, 10 different lumen diameters (1.6 to 3.4 mm) were produced in a Perspex block, and six different wall compliances produced with silicone tubes of constant inner diameter (2.0 mm) but different outer diameters (3.5 to 6.0 mm) A standard PTCA balloon was inflated under automatic control at a constant rate of 0.05 ml s-1 to 800 kPa (8 bar). Pressure and volume data were recorded to computer continuously throughout the procedure. Differences in lumen volume of +/-0.01 ml and wall compliance of +/-5% could be differentiated with greater than 95% confidence. We conclude that our technique allows small changes in lumen volume and wall compliance to be differentiated using a standard angioplasty catheter and balloon.