Pathology of Drug-Eluting Stents in Humans

• Published in: Journal of the American College of Cardiology 2006-07, Vol.48 (1), p.193-202
• Main Authors: Joner, Michael, Finn, Aloke V., Farb, Andrew, Mont, Erik K., Kolodgie, Frank D., Ladich, Elena, Kutys, Robert, Skorija, Kristi, Gold, Herman K., Virmani, Renu
• Format: Article
• Language: English
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/j.jacc.2006.03.042

Pathology of Drug-Eluting Stents in Humans: Delayed Healing and Late Thrombotic Risk Michael Joner, Aloke V. Finn, Andrew Farb, Erik K. Mont, Frank Kolodgie, Elena Ladich, Robert Kutys, Kristi Skorija, Herman K. Gold, Renu Virmani Recent data suggest the window of thrombotic risk for drug-eluting stents (DES) extends far beyond that for bare-metal stents (BMS). We examined 23 cases of human DES (Cypher and Taxus) implants >30 days old (14 of which had evidence of late stent thrombosis [LST]) and found significantly greater delayed arterial healing when compared with a registry of BMS of similar implant duration. Additional pathologic risk factors for DES LST were: 1) local hypersensitivity reaction; 2) ostial and/or bifurcation stenting; 3) malapposition/incomplete apposition; 4) restenosis; and 5) strut penetration into a necrotic core. This study examined human drug-eluting stents (DES) to determine the long-term effects of these stents on coronary arterial healing and identified mechanisms underlying late stent thrombosis (LST). Although DES reduce the need for repeat revascularization compared with bare-metal stents (BMS), data suggest the window of thrombotic risk for Cypher (Cordis Corp., Miami Lakes, Florida) and Taxus (Boston Scientific Corp., Natick, Massachusetts) DES extends far beyond that for BMS. From a registry of 40 autopsies of DES (68 stents), 23 DES cases of >30 days duration were compared with 25 matched autopsies of BMS implantation. Late stent thrombosis was defined as an acute thrombus within a stent >30 days old. Of 23 patients with DES >30 days old, 14 had evidence of LST. Cypher and Taxus DES showed greater delayed healing characterized by persistent fibrin deposition (fibrin score 2.3 ± 1.1 vs. 0.9 ± 0.8, p = 0.0001) and poorer endothelialization (55.8 ± 26.5%) compared with BMS (89.8 ± 20.9, p = 0.0001). Moreover, DES with LST showed more delayed healing compared with patent DES. In 5 of 14 patients suffering LST, antiplatelet therapy had been withdrawn. Additional procedural and pathologic risk factors for LST were: 1) local hypersensitivity reaction; 2) ostial and/or bifurcation stenting; 3) malapposition/incomplete apposition; 4) restenosis; and 5) strut penetration into a necrotic core. The Cypher and Taxus DES result in delayed arterial healing when compared with BMS of similar implant duration. The cause of DES LST is multifactorial with delayed healing in combination with other clinical and procedural risk factors playing