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Platelet reactivity not linked to clinical outcomes after PCI in patients with PAD
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Peripheral artery disease was linked to an increased risk for adverse events after PCI with a drug-eluting stent, but this association was not directly affected by high platelet reactivity, according to a substudy of ADAPT-DES.
The researchers used the VerifyNow P2Y12 assay (Accumetrics) to measure platelet reactivity in patients with (n = 876) and without a history of PAD (n = 7,706) who were followed for 2 years after PCI with a DES. Patients were treated with aspirin indefinitely and clopidogrel for at least 1 year after PCI. High on-treatment platelet reactivity was defined as P2Y12 reaction units greater than 208.
No significant differences were noted between patients with PAD and those without PAD in mean P2Y12 reaction units (194 vs. 187; P = .07) or frequency of high platelet reactivity (45.4% vs. 42.4%; RR = 1.07; 95% CI, 0.99-1.16), according to the data.
Worse outcomes
At 2 years, patients with PAD had worse outcomes than those without PAD. The probable or definite stent thrombosis rate was 2.9% in patients with PAD and high platelet reactivity, 1.6% in patients with PAD alone, 1.4% in patients with high platelet reactivity alone and 0.7% for patients with neither PAD nor high platelet reactivity (P < .001).
Similarly, rates for MI were 11.8% in patients with PAD and high platelet reactivity, 6% in those with PAD alone, 4.9% for those with high platelet reactivity alone and 3.8% for those with neither PAD nor high platelet reactivity (P < .0001).
Patients with PAD also had higher rates of all-cause mortality: 8.5% in patients with PAD and high platelet reactivity, 7.5% in patients with PAD alone, 4.4% in patients with high platelet reactivity alone and 2.6% in patients with neither PAD nor high platelet reactivity (P < .0001).
For clinically relevant bleeding, the researchers found higher rates in patients with PAD but lower rates in those with high platelet reactivity (P < .0001).
The associations between high platelet reactivity and adverse events were similar for patients with PAD and those without PAD, with no evidence of interaction (P for interaction > .05), according to study results.
In a propensity-adjusted multivariable model, PAD and high platelet reactivity were independent predictors MI through 2 years (PAD, HR = 1.4; 95% CI, 1.07-1.84; high platelet reactivity, HR = 1.27; 95% CI, 1.03-1.57). PAD also proved to be an independent predictor of MI, MACE, cardiac death and clinically relevant bleeding. Additionally, the researchers noted an independent association for PAD and all-cause mortality, but not for high platelet reactivity, through 2 years.
Patients with PAD were more likely to be older and have more comorbidities than those without PAD, according to the data.
No direct mediation
“These data suggest that although a history of PAD was associated with ischemic and bleeding outcomes 2 years after successful coronary [DES] implantation, these associations did not seem to be directly mediated by heightened platelet reactivity,” the researchers wrote. – by Melissa Foster
Disclosures: The ADAPT-DES study was sponsored by the Cardiovascular Research Foundation, with funding provided by Abbott Vascular, Accumetrics, Biosensors, Boston Scientific, Cordis, Daiichi Sankyo, Eli Lilly, Medtronic, The Medicines Company and Volcano. Please see the study for a list of the researchers’ financial disclosures.
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