Abstract 4153: High Incidence of Coronary Vasospasm After Sirolimus-Eluting Stent Implantation: Role of Rho-associated Kinase Activation
Background: Widespread use of sirolimus eluting stents (SES) has raised new clinical issues including late stent thrombosis and coronary vasospasm, both of which may cause coronary adverse events. We hypothesized that SES predisposes coronary arteries to vasospasm and that Rho-associated kinase (ROCK) activation plays a mechanistic role.
Methods and Results: During Dec. 2007 through April 2009, we recruited 46 patients who underwent follow-up coronary angiogram 6-month after percutaneous coronary intervention without angiographically-proven coronary spastic angina. In subjects without restenosis, we challenged intracoronary acetylcholine (5, 15, 50 μg/artery) to induce coronary vasospasm. Acetylcholine induced vasoconstriction (5 μg) was significantly enhanced in SES-implanted segments than in bare metal stent (BMS)- or naïve coronary arteries (Figure⇓). The incidence of coronary vasospasm (>50 % vasoconstriction at maximal doses of acetylcholine) with ischemic ECG changes, lactate production in coronary sinus or angina pectoris was 78 % in BMS and 89 % in SES subjects. ROCK activity shown as phosphorylation of myosin binding subunit (MBS) in coronary sinus blood was significantly higher in subjects with acetylcholine-inducible coronary vasospasm than without (pMBS/MBS 1.85±1.15 vs. 0.57±0.64, p<0.05).
Conclusion: SES predisposes coronary arteries to vasospasm. ROCK activation might play a mechanistic role.