In vivo assessment of coronary artery angioplasty and stent deployment from balloon pressure-volume data

This study assessed the clinical and practical value of angioplasty balloon pressure-volume data, obtained by a computer-controlled balloon inflation device, during standard percutaneous coronary intervention (PCI) procedures. Stent deployment was studied for 57 lesions in 34 patients. Angiographic predilation data were available in 9 patients. Vessel lumen improvement with pre-dilation was determined using the area difference under the pressure-volume curves of two consecutive inflations and compared to the angiographically determined lumen improvement. Stent opening pressure, the inflation volume needed to unfold the stent and the shape of the pressure-volume curve were assessed for differences between stent sizes (diameter, length) and manufacturer types. A Pearson correlation of 0.8 between the pressure-volume area difference and the angiographic lumen improvement was significant (p = 0.01), confirming that pressure-volume curves are useful in assessing lumen improvement after pre-dilation. There was a significant difference in stent opening pressure between stent types but not between different stent sizes (length, diameter). The inflation volume measured during the unfolding process of the stent correlated with the calculated stent lumen when deployed (Pearson correlation: 0.65, p = 0.001). The shape of the pressure-volume curve during stent deployment illustrated differences between different stent sizes (length, diameter) during inflation. Pressure-volume curves obtained from an automatic balloon inflation device have shown their usefulness in providing additional feedback about lumen improvement and the mechanical characteristics and quality of stent deployment.