In previous columns I’ve reviewed three clinical decision support apps released by the ACC: the ASCVD Risk Estimator, the Guideline Clinical app and the Statin Intolerance app. Having been impressed with both the utility and simplicity of these apps, I was pleased to hear the ACC had released the DAPT Risk Calculator app for guiding dual antiplatelet therapy.

By simplifying often complex guidelines into a streamlined decision-support tool, the DAPT Risk Calculator app should help save time at the point of care.

There is a fine balancing act for patients who are receiving DAPT (aspirin plus a P2Y12 inhibitor) that has been the subject of many recent studies. On one hand, prolonged use of DAPT can lead to increased risk of bleeding; conversely, stopping too early can increase the risk of ischemic events. This past fall a joint ACC/American Heart Association Task Force released guidelines in the Journal of the American College of Cardiology related to the duration of DAPT in patients with coronary artery disease.¹ Shortly after, in December 2016, the ACC released the DAPT Risk Calculator, available on iTunes, Google Play, and as web format for convenience.

The application provides clinical decision support for clinicians evaluating the continuation of DAPT therapy for patients at least 12 months post PCI. The DAPT Risk Score² is a numerical value between –2 and +9, with a favorable benefit/risk ratio for prolonged DAPT being 2 or more and an unfavorable benefit/risk ratio being less than 2.

Factors used to calculate this score include age (75 or older is –2, 65 to 74 is –1 and under 65 is 0); patient characteristics (current cigarette smoker within the last 2 years, diabetes, myocardial infarction (MI) at presentation, prior PCI or prior MI, each 1 point); and procedural factors (stent diameter <3 mm and paclitaxel-eluting stent each 1 point; congestive heart failure (CHF) or left ventricular ejection fraction (LVEF) <30 percent and saphenous vein graft PCI, each 2 points).

The app provides a simple interface to fill in these characteristics and obtain a DAPT Risk Score with a percent risk for three endpoints: stent thrombosis/MI, major adverse cardiovascular and cerebrovascular event (MACCE) and GUSTO moderate-severe bleeding.

I tried both the iOS and web applications. My hypothetical patient is a 78-year-old (–2 points) with prior MI/PCI (+1 point), cigarette smoking within last two years (+1 point), history of CHF/LVEF less than 30 percent (+2 points) and stent diameter less than 3 mm (+1 point) for a score of +3. The results section provides an easy to understand break down of the change in risk for each of the three endpoints if DAPT is continued versus discontinued (Figure).

One of the elements of the app I like best is the simple toggle function for each of the characteristics that changes the DAPT Risk Score in real time. This provides a visual reminder for contributing factors to DAPT risk. Furthermore, the results page provides a way to email the output to a colleague or the patient, though the app is certainly meant more for clinicians. Unlike the ACC’s Statin Intolerance app which had blood cholesterol and lifestyle recommendations, I wasn’t able to find any patient-facing resources related to DAPT. There are at least six physician-facing resources, however, such as a link to the JAMA article that first published the study of the decision support tool, as well as a DAPT-focused update hub.

By simplifying often complex guidelines into a streamlined decision-support tool, the DAPT Risk Calculator app should help save time at the point of care. It’s important to note that the app is not a stand-alone decision-support tool and needs to be combined with appropriate clinical judgment to account for differences in patient presentations and needs. The main limitation of the DAPT Risk Score Calculator is not the app itself, but rather the score calculation, which hasn’t yet integrated other important factors because these require validation through research studies. For example, the DAPT Risk Score doesn’t account for baseline variables such as presence of anemia and oral anticoagulant therapy – both important for predicting risk of bleeding while on DAPT.

References

1. Levine GN, Bittl JA, Brindis RG, et al. J Am Coll Cardiol 2016;68:1082-115.
2. Yeh RW, Secemsky E, Kereiakes DJ, et al. JAMA 2016;315:1735-49.

Keywords: ACC Publications, Cardiology Magazine, American Heart Association, Anemia, Anticoagulants, Coronary Artery Disease, Decision Support Systems, Clinical, Diabetes Mellitus, Drug-Eluting Stents, Heart Failure, Hemorrhage, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Myocardial Infarction, Life Style, Odds Ratio, Point-of-Care Systems, Saphenous Vein, Smoking, Stroke Volume, Thrombosis