DES Appear Safe and Effective in SVG PCI
Drug-eluting stents (DES) and bare-metal stents (BMS) appear equally safe for percutaneous coronary intervention (PCI) in saphenous vein grafts (SVGs), but DES are associated with lower long-term mortality, according to a large registry study published in the October 28, 2014, issue of the Journal of the American College of Cardiology. The long-term rate of myocardial infarction (MI), however, did not differ between the stents.
Methods
Thomas T. Tsai, MD, MSc, of the Veterans Affairs (VA) Eastern Colorado Health Care System (Denver, CO), and colleagues retrospectively examined data from 2,471 veterans who underwent SVG PCI from October 2007 through September 2011 at 63 VA PCI-capable hospitals. Outcomes were compared using a propensity-matched analysis including 895 patients who received BMS and 901 who received DES.
Most patients in the overall cohort (63%) received DES during the study period, but DES use grew with each calendar year, increasing from 50% in 2008 to 69% in 2011.
The incidence of procedural complications was low in both groups (2.8% with BMS vs 2.3% with DES; P = .54), but differences between the groups emerged over the longer term.
Through a mean follow-up of 2.8 years, DES use was associated with a lower risk of death in the propensity-matched analysis (HR 0.72; 95% CI 0.57-0.89). The risk of MI through a mean follow-up of 2.5 years, however, was similar between the DES and BMS groups (HR 0.94; 95% CI 0.71-1.24).
Additional analysis showed that the comparative outcomes were unaffected by whether patients in the DES arm received first- or second-generation devices.
Findings Reassuring, but Questions Remain
In an accompanying editorial Christodoulos Stefanadis, MD, of Hippokration Hospital (Athens, Greece), observes that the finding of similar safety profiles between DES and BMS was also seen in the ISAR-CABG trial.
“Results of that study and of subsequent meta-analyses succeeded in appeasing... initial concerns about DES safety in SVG PCI, without, however, providing definitive answers for long-term safety,” he writes.
The VA study is one of the largest and longest follow-up trials to examine the safety and efficacy of DES in patients undergoing SVG PCI, Dr. Tsai and colleagues note.
“In our cohort, most patients receiving DES received a second-generation DES, which suggests that second-generation DES and BMS have comparable safety,” they add.
But while the new findings are reassuring, Dr. Stefanadis writes, several questions about the late safety of DES in SVG PCI remain. No data on cardiac mortality were available for the cohort, which hampers comprehensive assessment of outcomes. In addition, dual antiplatelet therapy status was not known, preventing evaluation of how different antiplatelet strategies affected outcomes.
“In the absence of confirmatory randomized data, the lower mortality rate observed with DES should, therefore, be interpreted with caution and regarded as an unproven hypothesis,” he writes, explaining that the lack of angiographic follow-up “does not allow the late behavior of DES implanted for treatment of SVG disease to be elucidated.”
Another significant trial limitation, according to David E. Kandzari, MD, of Piedmont Heart Institute (Atlanta, GA), was the failure to report the frequency of revascularization.
“The real role of DES is to reduce restenosis and avoid repeat revascularization,” he told TCTMD in a telephone interview. He added that the finding of a lower mortality rate in the DES group without a reduced MI rate raises more questions than it answers.
“It remains speculative what the translation of lower mortality is in the absence of lower MI,” he said.
Longer Follow-up Needed
David P. Taggart, MD, PhD, of the University of Oxford (Oxford, England), said the follow-up of less than 3 years is not long enough to conclude that DES and BMS have similar safety profiles in this patient population. “It is not uncommon for studies that show no differences at 1 and 2 years to show big differences at 5 years,” he told TCTMD in a telephone interview.
“At 2-plus years [of follow-up] all we can really say from this study is that the results are encouraging, but it is still early days,” he said, adding that larger, longer clinical trials are needed.
“Traditionally, results from stenting vein grafts have been pretty dismal,” he said. “Therefore, anything with the potential to improve outcomes is clearly important.”
Meanwhile, Dr. Taggart pointed out, the dramatic increase in DES use for SVG PCI shows that interventional cardiologists are “voting with their feet.”
Sources:
1. Aggarwal
V, Stanislawski MA, Maddox TM, et al. Safety and effectiveness of drug-eluting
versus bare-metal stents in saphenous vein bypass graft percutaneous coronary
interventions: insights from the Veterans Affairs CART program. J Am Coll Cardiol. 2014;64:1825-1836.
2. Stefanadis C. Are drug-eluting stents safe in the long term after saphenous vein graft intervention? lessons learned from real-world practice [editorial]. J Am Coll Cardiol. 2014;64:1837-1839.
Disclosures:
- Drs. Tsai, Kandzari, Stefanadis, and Taggart report no relevant conflicts of interest.
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