title: Underexpansion of sirolimus-eluting stents: incidence and relationship to delivery pressure.
abstract: We aimed to assess the incidence of underexpansion and the relationship between delivery pressure and expansion with sirolimus-eluting stents. Adequate stent expansion contributes to early and late improved outcomes. In 51 patients (53 lesions) with native coronary artery narrowing, balloon-expandable sirolimus-eluting stents (Cypher) were serially expanded with gradual balloon inflations [14 atm, 20 atm, and in case of minimal stent cross-sectional area (CSA)/reference lumen CSA < 50% at 20 atm, postdilatation with 0.5 mm larger balloon]. Intravascular ultrasound (IVUS) imaging was performed before intervention and after each gradual balloon inflation. Stent expansion (minimal stent CSA/reference lumen CSA) was measured. Stent expansion was 72% +/- 16% after 14 atm balloon inflation, 90% +/- 18% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and 90% +/- 18% at the end of the procedure (including optional postdilatations with 0.5 mm larger balloon; P = NS vs. 20 atm). Stent expansion addressed by MUSIC criteria (all struts apposed, no tissue protrusion, and final lumen CSA > 80% of the reference or > 90% if minimal lumen CSA was < 9 mm2) was adequate in 15% of the cases after 14 atm balloon inflation, in 60% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and in 60% at the end of the procedure (P = NS vs. 20 atm). Sirolimus-eluting stent underexpansion is common when deployed at conventional pressures. Increasing balloon delivery pressure or assessing stent expansion with IVUS seems warranted in order to ensure adequate sirolimus-eluting stent deployment.
authors.affiliation: Division of Cardiology, Washington Hospital Center, Washington, District of Columbia 20010, USA.
authors.forename: Edouard
authors.initials: E
authors.lastname: Cheneau
authors.forename: Lowell F
authors.initials: LF
authors.lastname: Satler
authors.forename: Esteban
authors.initials: E
authors.lastname: Escolar
authors.forename: William O
authors.initials: WO
authors.lastname: Suddath
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Kent
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Weissman
authors.forename: Ron
authors.initials: R
authors.lastname: Waksman
authors.forename: Augusto D
authors.initials: AD
authors.lastname: Pichard
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000628:therapy*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011312:Pressure; D011446:Prospective Studies; D020123:Sirolimus / Q000008:administration & dosage*; D015607:Stents; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
chemical_list: D007166:Immunosuppressive Agents; D020123:Sirolimus