Bare metal, drug-eluting stents equally effective in treating saphenous vein grafts
Saphenous vein graft (SVG) lesions can be treated just as well with bare metal stents (BMS) as drug-eluting stents (DES), suggests a double-blind, randomized trial published May 11 in The Lancet.
“The study results have important economic implications in countries with high DES prices such as the USA, because they suggest that the lower cost BMS can be used in SVG lesions without compromising either safety or efficacy,” wrote lead author Emmanouil S. Brilakis, MD, and colleagues.
The researchers randomized 597 patients 1:1 to each stent group across 25 U.S. Department of Veterans Affairs medical centers. Patients averaged 68.6 years old and all but two of them were men. They were all deemed to require percutaneous coronary intervention (PCI) to treat at least one significant (2.5-4.5 mm) de-novo SVG lesion of 50 to 99 percent stenosis.
Operators were free to use the DES or BMS of their choice, with most opting for second-generation DES and newer-generation BMS with thin struts.
After adjustment, there was a nonsignificant 8 percent relative reduction in target vessel failure at one year for the DES group. Over the entire median follow-up of 2.7 years, the incidence of target vessel failure was 37 percent in the DES group and 34 percent in the BMS group. Target vessel failure was defined as a composite of cardiac death, target vessel myocardial infarction (MI) or target vessel revascularization.
“The absence of benefit with DES … could be related to the different pathophysiology of SVG atherosclerosis (more concentric and diffuse with less well defined fibrous cap) compared with native coronary artery atherosclerosis,” Brilakis et al. wrote. “The absence of benefit with DES could also be because of the large burden of comorbidities among patients with a previous CABG, or the use of thin-strut bare-metal stents that might have lower risk for restenosis as compared with thicker strut stents that were used in previous SVG PCI studies.”
The authors also noted there were no significant between-group difference in all-cause mortality, MI, stroke or stent thrombosis.
SVG failure is a common complication of coronary artery bypass graft (CABG) surgeries. About 6 percent of all PCIs in the U.S. are done in SVGs, the authors pointed out.
And while DES have demonstrated improved outcomes for native lesions, the previous studies of DES versus BMS for SVGs were limited by small sample size, an absence of blinding, lack of routine angiographic follow-up and the use of earlier generation devices.
Brilakis and colleagues noted their study results might not apply to women, as their patient population was almost entirely men.
In a linked editorial, Sven Möbius-Winkler, MD, PhD, and Raban V. Jeger, MD, said the characteristics of SVG lesions differ from native coronary artery lesions. Accordingly, different stents may afford different advantages for the treatment of these two types of vessels.
“The predominant use of second-generation DES in SVG disease did not—whereas the use of first-generation DES did—show a benefit with respect to a 12-month clinical endpoint compared with BMS,” the editorialists wrote, interpreting results from all available studies. “On the basis of these discrepant findings and the different pathophysiology of SVG and native coronary vessels, the ideal stent type for SVG disease could be hypothesized to be different from that for native vessel disease.
“However, this conclusion is speculative. Further research comparing the effect of different stent types in SVG disease is warranted.”
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.