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Development of Coronary Aneurysm after Drug-Eluting Stent Implantation

Background: The problem of drug-eluting stents increasing the risk for late thrombosis, especially when antiplatelet therapy becomes interupted, is a growing concern (1). Recently, a new association with these devices was observed at our institution (Cleveland Clinic, Cleveland, Ohio). Objective: To report cases of coronary aneurysm after drug-eluting stent implantation and to describe the different strategies used to treat the problem. Case Report: An aneurysm (8 mm in diameter by intravascular ultrasonography) was discovered in a 49-year-old woman 19 months after implantation of a sirolimus-eluting stent (CYPHER, Cordis Corp., Miami Lakes, Florida) (Figure 1). The patient underwent excision of the aneurysm with a bypass graft to the distal artery. Pathologic examination of the aneurysm revealed eosinophilic infiltration. Figure 1. Coronary aneurysm after stent implantation. A 44-year-old man had a coronary aneurysm (14 mm in diameter by intravascular ultrasonography) that was discovered 21 months after implantation of 2 paclitaxel-eluting stents (TAXUS, Boston Scientific, Natick, Massachusetts) (Figure 2). The patient underwent successful coiling of the aneurysm. Figure 2. Coronary aneurysm after stent implantation ( A ) and coronary aneurysm coiling ( B ). A 45-year-old man had an aneurysm that was discovered 6 months after implantation of a paclitaxel-eluting stent. After 12 months of clinical surveillance, repeated angiography revealed nearly complete resolution of the aneurysm (Figure 3). Figure 3. Stent implantation ( A ), coronary aneurysm after stent implantation ( B ), and nearly complete aneurysm resolution after stent implantation ( C ). A 49-year-old woman had a coronary aneurysm that was discovered 10 months after implantation of a sirolimus-eluting stent. Intravascular ultrasonography of the left main artery revealed an aneurysm without evidence of dissection or thrombus (Figure 4). The plan is for continued clinical surveillance. Figure 4. Left main artery aneurysm ( white arrow ) and dilatation of the left anterior descending sirolimus-eluting stent ( black arrow ). Discussion: The incidence of coronary aneurysm after the use of drug-eluting stents is currently unknown. In the Treatment of De Novo Coronary Disease Using a Single Paclitaxel Eluting Stent V (TAXUS-V) trial (2), the incidence was 1.4% with paclitaxel-eluting stents, compared with a 0.2% prevalence with bare metal stents (P= 0.07). Moreover, in 2 of our patients, no angiographic abnormalities with coexisting bare-metal stents were found. Late stent thrombosis and coronary aneurysm formation may share the same pathogenesis of localized hypersensitivity to drug-eluting stents (3). Similar inflammatory reactions have not been seen with bare-metal stents (4). Aneurysm formation was also not explained by obvious technical factors, such as the use of excessive pressure during stent deployment or the use of oversized stents. In all patients, stent size appeared to be well-matched to reference vessel diameter. Conclusion: Coronary aneurysm formation can occur in all coronary distributions after the use of drug-eluting stents. Currently, the natural history and best treatment for the problem is unknown; however, some aneurysms resolve. Because they may be serious problems, some aneurysms should be considered for surgical excision, percutaneous coiling, or placement of a covered stent.