Better Inflation Time of Stent Balloon for Second-Generation Drug-Eluting Stent Expansion and Apposition: An Optical Coherence Tomography Study

Objectives We tried to determine the effect of stent balloon inflation time on stent expansion and apposition using optical coherence tomography. Background Second-generation drug-eluting stents (DES) have thin struts; however, inflation times for optimal stent expansion and apposition are unknown in vivo. Methods Subjects included 17 patients (18 de novo coronary artery lesions), in whom Resolute Integrity -> (n = 9) and Xience Prime -> (n = 9) DES were deployed. All stents were inflated 3 times to the nominal inflation pressure (8.9 +/- 0.6 atm) using the stent delivery balloon. The first inflation continued until the stent was angiographically fully expanded; the other 2 lasted 15 and 30 seconds, respectively. Results After the first, second, and third inflation of stent balloon, stent area (5.94 +/- 1.7, 6.69 +/- 1.8, 7.05 +/- 1.8 mm(2), P < 0.001) and stent volume (146.94 +/- 59.40, 166.78 +/- 69.55, 177.25 +/- 69.19 mm(3), P < 0.001) increased significantly. The number of malapposed struts (18.0 +/- 17.0, 7.9 +/- 10.2, 7.4 +/- 10.8, P < 0.001) and the mean depth of malapposed struts (188.9 +/- 75.6, 120.3 +/- 101.4, 95.4 +/- 86.8 mu m, P < 0.001) decreased. Malapposed stent area (0.62 +/- 0.32, 0.52 +/- 0.21 mm(2), P < 0.05) and the malapposed stent volume (15.03 +/- 7.78, 12.64 +/- 5.16 mm(3), P < 0.05) decreased significantly following the second inflation; the third inflation gave no additional benefits to these parameters. There was no adverse clinical outcome after each stent balloon inflation. Conclusions Additional 15 seconds of inflation after the angiographically full expansion of the stent balloon allows better stent expansion and apposition even though the inflation pressure is nominal pressure. (J Interven Cardiol 2014;27:171-176)