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DAPT Risk Score Picks Patients for Extended Tx

<ѻý class="mpt-content-deck">— "This is exactly what we need" to balance benefit and risk, experts say
Last Updated November 12, 2015
MedpageToday

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A new risk calculator that simultaneously weighs bleeding and ischemic risk for continuing dual antiplatelet therapy (DAPT) beyond 1 year after percutaneous coronary intervention (PCI) got an enthusiastic welcome when announced at the American Heart Association meeting.

The calculator assigns a numerical score with a range of -2 to 10, developed using data from the 11,648 patient DAPT trial, MD, MSc, MBA, of Beth Israel Deaconess Medical Center and Harvard Medical School, reported at the meeting in Orlando.

The number needed to treat to prevent an ischemic event for patients with a DAPT score of 2 or higher was 34 and the number needed to harm with a bleeding event was 272. For patients with a score less than 2, those numbers flip-flopped to 153 to benefit and 64 to harm.

The extended-DAPT risk calculator is available and is expected to become an app for mobile devices as well.

"This is exactly what we need," , of the University of North Carolina at Chapel Hill and a past president of the AHA, told ѻý. "The ability to compare the benefit with the risk and decide what might be best for a given patient is extraordinarily useful."

Factors included to calculate the score are:

  • Age (-2 for age 75 or older and -1 for 65 to under 75)
  • Diabetes (1 point)
  • Prior myocardial infarction or PCI (1 point)
  • MI at presentation (1 point)
  • Stent diameter less than 3 mm (1 point)
  • PCI done with a vein graft (2 points)
  • Heart failure or ejection fraction under 30% (2 points)

Discussants at the late-breaking clinical trial session called the tool "welcome" but also "parsimonious."

Hypertension, renal insufficiency, and peripheral arterial disease predict both ischemia and bleeding, and thus were not included, Yeh said.

, of UT Southwestern Medical Center at Dallas and a discussant at the press conference for the late-breaking trial session, suggested that having such a risk score would even change his view of the findings.

Although the primary trial results showed a 71% reduction in stent thrombosis with 30 months of dual therapy versus aspirin alone, de Lemos said the elevated moderate or severe bleeding risk nullified that benefit for him overall.

With the score there is a "more clearly favorable" net effect for a "sizable subset of post-PCI patients," he said.

However, he noted that the DAPT Study included only patients who completed 12 months of dual-anti platelet therapy uneventfully, and then were randomized to continue a thienopyridine plus aspirin versus aspirin alone.

The score can only be applied to a DAPT-like population who tolerate the first year and are clinically stable, he suggested.

Another limitation was the moderate discrimination, "comparable to other scores widely used," de Lemos said, although noting it could improve with further work. Smith also pointed to lack of data on ticagrelor (Brilinta) in DAPT as a "minor" limitation.

It is likely that the same factors play into risk and benefit in the first 12 months, Yeh said, and "we are now working on that population (0-12 months) within the DAPT data."

As a member of the ACC/AHA writing group working on updating recommendations for DAPT therapy, Smith said that the score may be considered for inclusion, although validation may be a question.

Disclosures

The analysis of DAPT was supported by the National Heart, Lung, and Blood Institute (K23HL118138) and Havard Clinical Research Institute.

Yeh said he received fees from Abbott Vascular, Boston Scientific, and Merck.

Primary Source

American Heart Association

Yeh RW, et al "Individualizing treatment duration of dual antiplatelet therapy after percutaneous coronary intervention: an analysis from the DAPT study" AHA Abstract 20297, LBCT 3.