After patients with peripheral artery disease undergo lower-extremity revascularization, they are at high risk for major adverse limb events, and new findings from a prespecified analysis of data from the VOYAGER-PAD trial show that treatment with the direct-acting oral anticoagulant rivaroxaban along with aspirin significantly cut the rate of total major adverse limb events in these patients.
These findings confirm the drop in first major adverse limb events linked to rivaroxaban treatment that was VOYAGER-PAD's primary result, reported just over a year ago.
The new total-event analysis also provides important insight into the huge magnitude of total major adverse limb events that patients with PAD can develop following lower-extremity revascularization (LER).
The 6,564 patients who all received aspirin and were randomized to either rivaroxaban (Xarelto) or placebo had 4,714 total events during a median follow-up of 2.5 years following their revascularization procedure. This included 1,092 first primary events (a composite of acute limb ischemia, major amputation for vascular causes, MI, ischemic stroke, or cardiovascular death), 522 primary events that occurred as second or subsequent events among patients after a first primary event (a nearly 50% increase from first events only), and 3,100 additional vascular events that did not fit into the primary-event category, most often a peripheral revascularization procedure, Rupert M. Bauersachs, MD, said at the annual scientific sessions of the American College of Cardiology.
"We were all astonished by this high event rate," Bauersachs said during his report.
The total-event analysis that he reported showed that treatment with rivaroxaban resulted in a significant 14% relative reduction, compared with placebo in the incidence of total primary events, which closely tracks the significant 15% relative reduction in first primary events reported from the VOYAGER-PAD trial in 2020. Treatment with rivaroxaban also significantly linked with a 14% cut in total vascular events, compared with placebo, including the many events not included in the primary endpoint, said Bauersachs, who until his retirement in May 2021 was director of the Clinic for Vascular Medicine at the Darmstadt (Germany) Clinic. Concurrently with the report, the results appeared online.
"If one focuses only on first events, you miss the totality of disease burden. There is even greater benefit by reducing total events," Bauersachs said during a press briefing. Adding rivaroxaban prevented roughly 2.6 first primary events for every 100 patients treated, but it also prevented 4.4 total primary events and 12.5 total vascular events for every 100 treated patients.
An "Incredibly High" Event Rate
"I don't think any of us imagined the level of morbidity in this population. The event rate is incredibly high," commented Joshua A. Beckman, MD, professor and director of vascular medicine at Vanderbilt University Medical Center, Nashville, Tenn.
Because treatment with rivaroxaban showed clear efficacy for also preventing subsequent events it should not be considered to have failed in patients who have a vascular event while on rivaroxaban treatment, he added as designated discussant for the report. Treatment with rivaroxaban "should be continued indefinitely," he concluded.
"It's quite astonishing to see the magnitude of [total] events in these patients," commented Sahil A. Parikh, MD, a cardiologist and director of endovascular services at Columbia University Medical Center in New York. "We've always known that these are high-risk patients, but exactly how high their risk is was not well understood until these data came to light."
Parikh also noted that, despite the clear evidence reported from VOYAGER-PAD more than a year ago proving the efficacy and safety of adding rivaroxaban to aspirin for long-term treatment of patients with PAD following LER, this regimen has not yet become standard U.S. practice.
Rivaroxaban Use Falls Short of the Expected Level
"This paradigm shift has not seen the level of adoption that we would expect based on the data," he said. "There have been numerous editorials and discussions of this at every major medical meeting" during the past year, but those expert opinions have not translated into changed practice. "Perhaps the pandemic has muted enthusiasm for adoption of a new therapeutic paradigm," suggested Parikh, and "on top of that guidelines have yet to be updated," although he noted that updated guidelines from the ACC and American Heart Association for PAD that include the types of patients enrolled in VOYAGER-PAD are now under review and should be released by the first half of 2022.
"I think the additional data [reported by Bauersachs] will encourage us to use rivaroxaban in patients with claudication," Parikh said. "Perhaps we should use rivaroxaban and aspirin in a broader swath of patients, but it will take time to convince some constituencies."
VOYAGER-PAD randomized patients with PAD who underwent successful LER within 10 days prior to enrollment at 542 sites in 34 countries during 2015-2018. In addition to every patient receiving 100 mg aspirin daily and either 2.5 mg rivaroxaban twice daily or placebo once daily, patients who received an intra-arterial device such as a stent could also receive the antiplatelet agent clopidogrel for a planned maximum of 30 days after revascularization at the discretion of their physician, and the trial protocol allowed for extending clopidogrel treatment to as many as 60 days.
In addition to the efficacy outcomes, the safety results showed that adding rivaroxaban to aspirin appeared to increase bleeding episodes, but at rates that generally did not reach significance and that were dwarfed by the efficacy benefit. The study's primary safety outcome was the incidence of Thrombolysis in Myocardial Infarction (TIMI) major bleeding episodes, which occurred in 2.65% of patients who received rivaroxaban and in 1.87% on those on placebo, a 43% relative increase that fell short of significance (P = .07). The analyses overall indicated that 10,000 similar patients treated for 1 year with rivaroxaban would have 181 fewer primary events, compared with placebo-treated patients at the cost of also having 29 additional TIMI major bleeding events compared with patient on placebo.
Adding Clopidogrel Adds Little Except Bleeding
Further analysis showed that just over half of enrolled patients also received clopidogrel for a median of 29 days following their LER procedure. This added agent produced no significant added benefit during 3-year follow-up, but did boost bleeding risk, especially in patients who received clopidogrel for more than 30 days. This led the study investigators to suggest that, while rivaroxaban plus aspirin is indicated for long-term treatment, addition of clopidogrel on top of this should be limited to 30 days or fewer to minimize bleeding risk.
"I'm sure there is a bleeding hazard associated with rivaroxaban plus aspirin, but this is attenuated by using dual therapy and not using triple therapy" by also adding clopidogrel, noted Parikh.
The new VOYAGER-PAD results also showed that the ongoing risk faced by patients with PAD following LER applies globally to their peripheral arteries. Of the 3,034 total peripheral revascularizations performed in the cohort during follow-up, 64% occurred in the index limb and 36% in the contralateral limb. Another striking finding was that the need for ipsilateral repeat revascularization was more common after an index endovascular procedure, 2,329 repeat revascularizations in 4,379 of these patients (53%), compared with 2,185 patients who had surgical revascularization for their index procedure and subsequently 705 of these patients (32%) needed repeat revascularization.
But rivaroxaban treatment appeared to provide little benefit for the much less frequent incidence of first and subsequent events in the coronary and cerebral circulation. During follow-up, the rates of major adverse cardiovascular events – cardiovascular death, nonfatal MI, and nonfatal stroke – were virtually identical in the rivaroxaban and placebo groups.
"This study makes it clear that we are learning about differences in presentation between the vascular beds, and the benefits of specific treatments in each vascular bed," Beckman said.
VOYAGER-PAD was sponsored by Bayer and Janssen, the companies that market rivaroxaban (Xarelto). Bauersachs has received personal fees from Bayer, as well as from Bristol-Myers Squibb, Daiichi Sankyo, and Pfizer, and has received grant support from Aspen Pharma. Beckman been a consultant to and received honoraria from Janssen, as well as from Amgen, JanOne, Novartis, and Sanofi, and he has served on a data and safety monitoring board for Bayer. Parikh has been a consultant to and received honoraria from Janssen, as well as from Abbott, Boston Scientific, Cordis, Medtronic, Penumbra, Philips, and Terumo, he has been a speaker on behalf of Inari, and he has received grant support from Abbott, Shockwave Medical, Surmodics, and TriReme Medical.
American College of Cardiology (ACC) 2021 Scientific Session.
This article originally appeared on MDEdge.com.
Medscape Medical News © 2021
Cite this: Rivaroxaban Cut Recurrent Limb Events in VOYAGER-PAD - Medscape - May 31, 2021.