Drug-eluting stents: are they really safe?

Drug-eluting stents have reduced the frequency of in-stent restenosis. However, most of the results have been derived from simple lesions in noncomplex patients. In preclinical normal pig and rabbit studies, bare-metal stents show complete healing at 28 days, whereas drug-eluting stents show incomplete healing with persistence of fibrin and incomplete coverage of the stent struts by endothelial cells. In human beings similar delayed healing has been observed at 6 and 12 months in atherectomy specimens or at autopsy. The US Food and Drug Administration posted adverse event information for physicians regarding subacute thrombosis and hypersensitivity reaction following deployment of sirolimus-eluting stents in human beings. The authors have seen, at autopsy, late (18 months) stent thrombosis, aneurysm formation, and extensive inflammatory reaction limited to the arterial wall surrounding the stent that they interpret as a hypersensitivity reaction to the polymer. The authors advocate caution and aggressive use of nontoxic systemic drugs to prevent the complications of atherosclerosis along with better postmarket surveillance of patients and histologic examination of tissue from patients with drug-eluting stents.