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The DAPT Score offers moderate predictive power in determining the patients most likely to benefit from dual antiplatelet therapy (DAPT) extending beyond 1 year after percutaneous coronary intervention (PCI), a study suggests.

Consisting of a scale between -2 and 10, the -- defined as myocardial infarction (MI) or stent thrombosis -- and 0.68 for predicting moderate-to-severe bleeding in patients receiving prolonged DAPT with aspirin and a thienopyridine, according to senior author of Brigham and Women's Hospital in Boston, and colleagues.

Prolonged DAPT in patients scoring two or above was associated with fewer ischemic events up to 30 months after stenting (2.7% versus 5.7% with placebo, P<0.001). Low scorers did not share the same benefit (1.7% versus 2.3% for placebo, P<0.001).

The high-scoring group also showed a smaller increase in bleeding risk with extended DAPT (1.8% versus 1.4% for placebo, P=0.07) than the lower scorers did (3.0% versus 1.4% for placebo, P<0.001), the investigators reported online in the Journal of the American Medical Association. The DAPT Score was previously presented at the American Heart Association meeting in 2015.

The for predicting both ischemia and bleeding in the validation cohort.

"Among patients not sustaining major bleeding or ischemic events 1 year after PCI, a prediction rule assessing late ischemic and bleeding risks to inform DAPT duration showed modest accuracy in derivation and validation cohorts," Mauri's group concluded.

The score was intended as "a simple tool to help put together the overall risks and benefits of treatment," Mauri told 乌鸦传媒視頻 by email.

But for now, "use of this prediction score should be cautious until further validation is performed, and optimal clinical and procedural care to reduce overall bleeding and ischemic risks should be practiced independent of a patient's score," her group noted.

The model's derivation cohort included 11,648 randomized patients who received either drug-eluting stents (DES) or bare metal stents (BMS) as part of the DAPT trial between 2009 and 2014. Validation was performed in patients separately enrolled in the PROTECT investigation.

The prediction rule assigned one point each for presentation with MI, prior MI or PCI, diabetes, stent diameter less than 3 mm, smoking, and paclitaxel-eluting stent; and two points each for history of congestive heart failure and vein graft intervention. One point was deducted for patients ages 65 to 75 and two taken away for those over 75.

Between 12 and 30 months, high scorers receiving prolonged DAPT were tied to a reduced risk of combined death, MI, and stroke (4.9% versus 7.6% for placebo, P<0.001), whereas low scorers did not exhibit a similar advantage on continued DAPT (3.7% versus 3.8%, P=0.73).

Of note was the finding in the validation cohort that high scorers had more ischemic events than low scorers (1.5% versus 0.7%, hazard ratio [HR] 2.01, 95% confidence interval [CI] 1.29-3.13) with no difference in bleeding (0.4% versus 0.5%, HR 0.69, 95% CI 0.33-1.42).

The external validation population was not randomized, however, so "these data could only be used to evaluate whether the score stratified patient ischemic or bleeding risk, and not actual benefit or harm with long-term dual antiplatelet therapy," Mauri's group wrote.

Another caveat was that their model "required an assumption that bleeding and ischemic events were of equal weight," whereas the authors acknowledged that these events in fact "may not have an equivalent effect on patient outcomes, including mortality."

Separating out the ischemic and bleeding models rather than using the simplified score could improve the ability to predict events for patients with discordant or concordant risks, Mauri and colleagues wrote.

The predictive scale also failed to take into account preexisting anemia, prior bleeding, and extent of atherosclerosis due to lack of data. That "may in part explain the modest discrimination of the ischemia and bleeding prediction," the group suggested. "In addition, patients receiving ticagrelor or other antiplatelet combinations could have a different risk-benefit relationship."

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