ROME -- Platelet function monitoring in elderly patients did not improve clinical outcomes after percutaneous coronary intervention (PCI) for an acute coronary syndrome, ANTARCTIC investigators found.
At 1 year, the combined rate of cardiovascular death, myocardial infarction, stroke, stent thrombosis, urgent revascularization, and bleeding complications was 28% (HR 1.003, 95% CI 0.78-1.29).
A purported tool to individualize antiplatelet therapy, the VerifyNow P2Y12 Assay did not reduce bleeding rates either (21% for monitored group versus 20% for control, HR 0.98, 95% CI 0.79-1.22), reported , of Pitié-Salpêtrière Hospital in Paris, and colleagues in their ANTARCTIC study presented at the .
The paper was simultaneously published online in .
"Platelet function testing is still being used in many centres and international guidelines still recommend platelet function testing in high-risk situations," they commented, highlighting the current European and American class IIb recommendations with level C evidence in high risk cases. "Our study does not support this practice or these recommendations."
"Platelet monitoring is difficult to use. [Patients] have to come back, it is costly, and there is no benefit," Montalescot said at a press conference.
"As a clinical interventionalist, I'm happy your study ended up the way it did," said press conference moderator , of Germany's University of Leipzig, with a nod to the extra patient visits associated with routine monitoring.
The data come as another blow to platelet testing, for which trials have consistently found little-to-no clinical benefit after PCI. A reboot of the negative ARCTIC study -- with higher-risk patients, urgent PCI, and prasugrel this time -- ANTARCTIC was a last-chance effort to demonstrate a clinical benefit of the VerifyNow assay.
But some were not convinced that these latest findings will be the death knell for platelet monitoring.
The study's choice of antiplatelet was a point of contention in an by , and , both of the German Center for Cardiovascular Research in Munich: Low-dose prasugrel was not shown to be superior to standard clopidogrel for elderly patients with an acute coronary syndrome, the duo commented, adding that pharmacodynamic testing should be done to compare their antiplatelet efficacy in this population.
, of Stanford University School of Medicine, Calif., said in an interview that platelet monitoring makes sense intuitively, which is why some just "can't let go of the idea despite evidence to the contrary."
"It will continue to die a slow death," he added.
Montalescot's present study recruited 877 patients at 35 participating centers in France. Patients were 75 or older and all received 5 mg prasugrel. Patients randomized to VerifyNow testing had it done 14 days after randomization and again 14 days after treatment adjustment.
Bleeding events were defined as those categorized as Bleeding Academic Research Consortium types 2, 3, or 5.
Disclosures
ANTARCTIC was supported by Eli Lilly, Daiichi Sankyo, Stentys, Accriva Diagnostics, Medtronic, and Fondation Coeur et Recherche.
Montalescot declared receiving grants from ADIR, Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Celladon, Daiichi Sankyo, Eli Lilly, ICAN, Fédération Française de Cardiologie, Medtronic, MSD, Pfizer, Sanofi-Aventis, and The Medicines Company; and personal fees from Amgen, AstraZeneca, Bayer, Berlin-Chemie, Boehringer Ingelheim, Bristol-Myers Squibb, Beth Israel Deaconess Medical, Brigham and Women's Hospital, Cardiovascular Research Foundation, CME Resources, Daiichi Sankyo, Eli Lilly, Europa, Elsevier, Fondazione Anna Maria Sechi per il Cuore, Gilead, Janssen, Lead-Up, Menarini, MSD, Pfizer, Sanofi-Aventis, The Medicines Company, TIMI Study Group, and WebMD.
Sibbing reported receiving speaker fees and honoraria for consulting from Eli Lilly, Daiichi Sankyo, Bayer Vital, Pfizer, AstraZeneca; and research funding from Roche Diagnostics.
Massberg disclosed no relevant conflicts of interest.
Primary Source
The Lancet
Cayla G, et al "Platelet function monitoring to adjust antiplatelet therapy in elderly patients stented for an acute coronary syndrome (ANTARCTIC): an open-label, blinded-endpoint, randomised controlled superiority trial" Lancet 2016; DOI: 10.1016/S0140-6736(16)31323-X.
Secondary Source
The Lancet
Sibbing D and Massberg S "Antiplatelet strategies in elderly people: still a long way to go" Lancet 2016; DOI: 10.1016/S0140-6736(16)31387-3.