Drug-eluting stents show delayed healing: paclitaxel more pronounced than sirolimus.
OBJECTIVE
To understand wound healing after drug-eluting stents (DES) placement in humans, we studied the histology of in-stent restenosis (ISR) tissue obtained by atherectomy from bare metal stents (BMS) and DES in comparison with de novo atherosclerosis.


RESULTS
The tissue was retrieved from ISR in ten sirolimus-eluting stents (SES) and nine paclitaxel-eluting stents (PES), six BMS, and nine stenotic de novo atherosclerotic lesions and processed for histology and immunocytochemistry. Patients with ISR in PES showed a significantly higher incidence of unstable angina upon presentation for re-intervention (P = 0.046). De novo tissue tended to be more collagen rich, whereas ISR tissue tended to be more proteoglycan rich. In all groups, cell content consisted almost exclusively of smooth muscle cells. Histology showed that fibrinoid in ISR tissue was present only in DES (P = 0.004), as late as 2 years following DES placement, indicating a persistent incomplete healing response. The amount of fibrinoid, given as a percentage of total tissue in each atherectomy specimen, was greater in PES than in SES (17 vs. 5%, P = 0.026).


CONCLUSIONS
ISR in DES shows incomplete neointimal healing as late as 2 years after implantation. Patients with ISR in PES presented with more unstable angina and showed more pronounced signs of delayed healing than SES.
van Beusekom
Heleen M M
HM
Department of Cardiology, Ee 2355b, Erasmus Medical Center Rotterdam, Dr. Molewaterplein 50, PO Box 1738, 3000 Rotterdam, The Netherlands. h.vanbeusekom@erasmusmc.nl
Saia
Francesco
F
Zindler
Jaap D
JD
Lemos
Pedro A
PA
Swager-Ten Hoor
Stijn L
SL
van Leeuwen
Maarten A H
MA
de Feijter
Pim J
PJ
Serruys
Patrick W
PW
van der Giessen
Willem J
WJ
D000368:Aged; D000369:Aged, 80 and over; D023903:Coronary Restenosis / Q000503:physiopathology / Q000517:prevention & control*; D004343:Drug Implants; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D017239:Paclitaxel / Q000008:administration & dosage*; D020123:Sirolimus / Q000008:administration & dosage*; D015607:Stents; D050257:Tubulin Modulators / Q000008:administration & dosage*; D014945:Wound Healing / Q000187:drug effects*
D004343:Drug Implants; D007166:Immunosuppressive Agents; D050257:Tubulin Modulators; D017239:Paclitaxel; D020123:Sirolimus