Four-Year Invasive Follow-Up of Drug-Eluting Stents
abstract & commentary
By Michael H. Crawford, MD
Professor of Medicine, Chief of Clinical Cardiology, University of
California, San Francisco
Synopsis: The beneficial effects of drug-eluting stents on coronary artery lumen enhancement are preserved for 4 years after implantation.
Source: Sousa JE, et al. Four-Year Angiographic and Intravascular Ultrasound Follow-Up of Patients Treated with Sirolimus-Eluting Stents. Circulation. 2005:111:2326-29.
Drug-eluting stents (DES) have been rapidly embraced because of the promise of less in-stent restenosis, yet long-term data are few. Thus, this international multicentered study of 30 consecutive patients treated with a single sirolimus-eluting Bx Velocity stent in 1999-2000 is of interest. A fast-release DES was implanted in 15 patients (FR, < 15-day release), and 15 had a slow-release DES (SR, < 28-day release). In 26 of these patients, 4-year angiography and intravascular ultrasound (IVUS) were done. All patients received aspirin indefinitely and clopidogrel (300 mg loading) 75 mg/day for 60 days. All patients had angio and IVUS follow-up scheduled for 4 months and 1, 2 and 4 years.
Results: Major adverse cardiac events occurred in 20% of the FR patients and 7% of the SR patients. One patient in the FR group died. He had severe left ventricular dysfunction, and experienced a cardiac arrest. Angio and IVUS showed no in-stent restenosis. Three patients had target vessel revascularization, but none occurred after 2 years of follow-up. In the SR group, there were no stent thromboses, target lesion revascularization, deaths, or MI. No patient developed aneurysms. In the 26 patients who had angio and IVUS at 4 years, only 1 FR patient developed restenosis. Only 1patient in the SR group developed more than 0.5 mm of late loss, whereas, 6 in the FR group did. Sousa and colleagues concluded that the beneficial effects of DES on coronary artery lumen enhancement are preserved for 4 years after implantation, especially with the SR formulation.
Commentary
We are all encouraged by the early results of DES, but have concerns about long-term effects. Could the anti-proliferative effects of DES lead to late arterial wall weakness, with aneurysm formulation and rupture? Will restenosis just be retarded, but eventually occur? Will there be other unforeseen consequences? This study, although small, would seem to put these fears to rest. Also, long-term effectiveness seems excellent, especially for the SR DES, which is available (Cypher®, Johnson & Johnson). There were no deaths, MI, or in-stent thrombosis; target lesion revascularization at 4 years with this stent and neointimal proliferation was minimal. It is hard to imagine that a longer follow-up will squelch these favorable results, but it will be more reassuring to see larger series with more patients.
The rate of drug release seemed important in this study, but it was not designed to compare the FR and SR stents, so further data on this issue are needed. There are other issues as well that were not addressed here, such as the type of drug, the binding material, etc. However, such excellent results with a commercially available product are encouraging and support the current switch to the preferential use of DES.
Professor of Medicine, Chief of Clinical Cardiology, University of California, San Francisco Synopsis: The beneficial effects of drug-eluting stents on coronary artery lumen enhancement are preserved for 4 years after implantation. Source: Sousa JE, et al. Four-Year Angiographic and Intravascular Ultrasound Follow-Up of Patients Treated with Sirolimus-Eluting Stents. Circulation. 2005:111:2326-29.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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