Better Inflation time of stent balloon on stent expansion and apposition: an optical coherence tomography study

Purpose: Adequate stent expansion and apposition are important for maintaining good clinical outcomes after coronary intervention. We determined the effect of inflation time of the stent balloon on stent expansion and apposition using optical coherence tomography. Methods: Subjects included 17 patients (18 de novo coronary artery lesions), in whom Resolute Integrity® (n=9) and Xience prime® (n=9) were deployed. The stents were inflated three times in all cases at the nominal inflation pressures (8.9±0.6 atm) by the stent delivery balloon with different inflation times of first, 15 seconds and 30 seconds. The first inflation time was determined by immediate deflation after confirming the full inflation of balloon. After each inflations, mean stent area, number of malapposed struts, mean depth of malapposed struts, malapposed stent area, malapposed stent volume were analyzed using optical coherence tomography. Results: After the first, second and third inflation of stent balloon, stent area increased, 5.9±1.7mm2, 6.7±1.8 mm2 vs. 7.0±1.8mm2, p<0.001) (Figure 1.) and the number of malapposed struts (16.1±15.3 vs. 7.9±10.2 vs. 5.6±7.6, p<0.001), and the mean depth of malapposed struts (188.9±75.6μm vs. 120.3±101.4μm vs. 95.4±86.8μm, p<0.001) decreased gradually (Table1). Mean Malapposed stent area (0.62±0.32 mm2 vs. 0.52±0.21mm2, p<0.05) and the malapposed stent volume decreased significantly after the additional inflation of 15 seconds than the first inflation (15.03±7.78 mm3 vs. 12.64±5.16mm3, p<0.05). There was no edge dissection after the each stent balloon inflation. View this table: Table 1 Conclusions: Repeated, additional 15s inflation time may allow better stent expansion and apposition even though the inflation pressure is nominal.