Mortality not different at 5 years in patients treated with DES vs. controls
LAS VEGAS — There were no significant differences in mortality at 5 years between patients with peripheral artery disease assigned a drug-eluting stent and those assigned a bare-metal stent or percutaneous transluminal angioplasty, according to new data presented at VIVA 19.
The mortality results did not differ in the intention-to-treat and as-treated analyses, Michael Dake, MD, senior vice president of health sciences and professor of medical imaging, surgery and medicine at the University of Arizona, said during a press conference. The topic has been at the forefront since a meta-analysis showing a long-term mortality signal associated with paclitaxel-coated devices was published in December 2018.
The researchers analyzed the 94% of patients from the 489-patient pivotal trial of the DES (Zilver PTX, Cook Medical) for whom 5-year mortality data were available.
In the intention-to-treat analysis, 21.7% of those assigned the DES died within 5 years compared with 15.2% of controls (P = .08), Dake said.
In the as-treated analysis, in which people who actually received treatment with the DES, which included crossovers and people who had a suboptimal PTA that underwent a secondary randomization to DES, were counted in the DES group, 19.1% of the DES group died within 5 years compared with 17.1% in the control group (P = .6), he said. In all, 40% of patients from the control group were eventually treated with the DES, he noted.
Dake noted that randomization was based only on lesion length, and the DES group had more risk factors than the control group (P < .01), so the numerically higher mortality rates in the DES group could be explained by the risk-factor disparity.
Patients with fewer risk factors had lower mortality rates, and the benefit of DES in freedom from target lesion revascularization was consistent across risk-factor groups, though the greatest benefit was observed in those with fewer risk factors, Dake said at the press conference.
“This raises an interesting question,” Dake said during the press conference. “We know all patients have risk. Who is a high-risk patient? It’s not just someone who has critical limb ischemia. The risk factors need to be further analyzed to determine their relative impact on mortality.”
The randomization process for such trials may need to change, Dake said in an interview.
“There are agreed-upon risk factors for mortality and a different set of risk factors for TLR,” Dake told Cardiology Today. “Some overlap, but most do not. So, in terms of randomization and accounting for balance, it matters what endpoint you are looking at. Remember, none of the trials were powered to look at mortality. In the future, new studies may need to take into account risk factors during randomization.” – by Erik Swain
Dake M, et al. Late-Breaking Clinical Trials. Presented at: VIVA 19; Nov. 4-7, 2019; Las Vegas.
Disclosures: The study was funded by Cook Medical. Dake reports he received consultant fees and/or honoraria from Bard Peripheral Vascular, Cook Medical, Novate and W.L. Gore and Associates.