Abstract 4155: Comparison of Stent Underexpansion and Recoil Between 4 Commercially Available First- and Second-generation Coronary Stents
Background: Failure to achieve predicted stent diameter caused by stent underexpansion and stent recoil poses a risk of treatment failure in coronary stenting. Due to improved stent design and delivery system, second-generation drug eluting stents (DESs) are expected to achieve more adequate stent expansion compared to first-generation. We analyzed the magnitude of stent expainsion and stent recoil between currently used first- and second-generation DESs.
Methods: A prospective angiographic study recruiting 112 lesions (96 patients) undergoing coronary stenting was performed. Quantitative coronary angiography using CAAS II (Cardiovascular Angiography Analysis System) was performed to measure the minimal lumen diameters of the delivery balloon during stent deployment (MLD1) and of the stented segment following balloon deflation (MLD2) in 4 stents group; Cypher (Cordis-Johnson and Johnson, USA, n=30), Taxus liberte (Boston Scientific, USA, n=27), Endeavor Resolute (Medtronic, USA, n=30), and Xience V (Abbott Vascular, USA, n=25). Delivery balloon deficit was measured by subtracting the MLD1 from the predicted balloon diameter determined from the manufacturer’s reference. Stent recoil was calculated by subtracting MLD2 from MLD1.
Results: Median stent balloon underexpansion and stent recoil were 0.75mm (25th 75th IQR 0.61– 0.87 mm) and 0.11 mm (0.00 – 0.32 mm), representing 23.1 % (19.5–27.3%) and 4.6% (0.0 –13.4%) less than predicted balloon diameter, respectively. Higher than nominal pressure (additional 2±2 mmHg) were used in 93/112 (83%) to deploy stent at the operator’s discretion. There were no differences in stent balloon underexpansion, stent recoil between 4 stents, which were independent of vessel size or lesion length. Optimal stent deployment defined as final MLD ≥90% of predicted diameter was achieved in 27/112 (24%) without post dilatation balloon angioplasty and was significantly more frequent in Xience V (3% vs. 4% vs. 0% vs. 20%, p=0.014).
Conclusion: All four types of first- and second-generation DESs yield suboptimal profiles of stent expansion and recoil property irrespective of vessel size even at higher maximal deployment pressures. Xience V shows better property in obtaining final MLD.