Platelets, also called thrombocytes are a component of blood that can clump together to form blood clots to stop bleeding. These blood clots can also lead to the sudden clotting of a coronary stent, as well as heart attack, stroke, and peripheral vascular disease.
Patients at risk of developing blood clots and associated diseases are treated with antiplatelet agents, a class of drugs that inhibit the platelets from clumping together and forming blood clots.
Many of these patients, especially those who had a heart attack, were treated with stents in their coronary arteries or had coronary artery bypass graft surgery (CABG) are treated with two types of antiplatelet agents to prevent blood clotting.
This is called dual antiplatelet therapy (DAPT), which includes aspirin as one antiplatelet agent, and one of three P2Y12 inhibitors or adenosine-diphosphate (ADP) receptor antagonists, including clopidogrel, prasugrel, or ticagrelor, as the second type of antiplatelet agent.
Almost everyone with coronary artery disease is treated with aspirin for the rest of their lives, while ADP receptor antagonists are usually prescribed for months or years in addition to the aspirin therapy, especially to patients who underwent post percutaneous coronary intervention (PCI).
In this case, the antiplatelet drugs are prescribed to reduce the rates of stent-related thrombosis in both the short and long term.
Current clinical guidelines recommend that dual antiplatelet therapy is continued for a minimum of 12 months following drug-eluting stent (DES) percutaneous coronary intervention (PCI).
The benefits of longer DAPT include a lower risk of stent thrombosis, myocardial infarction, and major adverse cardiovascular and cerebrovascular events.
However, a longer DAPT also means a greater risk of moderate to severe bleeding, so it is important that clinicians weigh the benefits and risks of the procedure and estimate the risk of stent thrombosis and bleeding in PCI patients.
This process wasn't straightforward or standardized until the development of the DAPT score which enabled clinicians to calculate the risk and benefit of continued DAPT and inform the patients about the best option for them.
The DAPT score tries to predict a combined ischemic and bleeding risk for patients being considered for a longer term continued P2Y12 receptor antagonist therapy in addition to aspirin beyond one year after coronary stent implantation.
Recently, the American College of Cardiology (ACC) released a standalone DAPT Risk Calculator app to provide a better decision support for clinicians evaluating the continuation of DAPT therapy for patients at least 12 months post PCI procedure.
This app is another great addition to the list of the other mobile medical apps the ACC developed for clinicians and patients.
The DAPT Risk Calculator app is based on the study and DAPT calculator published in JAMA in 2016.
The app interface is simple, using the same layout as other ACC apps. Basically, it features a calculator allowing users to input data relevant to the DAPT risk estimation, such as patient's age and medical history, i.e. if the patient has diabetes, hypertension, prior myocardial infarction, renal insufficiency, peripheral arterial disease, etc.
Clinicians also need to enter procedure characteristics that apply, selecting from myocardial infarction at presentation, stenting of a vein of graft, and stent diameter less than 3mm.
The DAPT Score Impact showing the increased bleeding risk vs. increased ischemic risk changes in real time, i.e. as clinicians enter the data into the calculator.
The Score Impact is shown at the top of the screen as a color-coded scale showing a numerical value between -2 (green) and +9 (red). The greener the color the greater bleeding risk, i.e. the redder the score the greater ischemic risk.
Also, a higher DAPT score suggests that the benefit/risk ratio with prolonged DAPT may be favorable, while a lower DAPT score suggests that the benefit/risk ratio with prolonged DAPT is not favorable.
For example, if a DAPT score is less than 2, patients probably should just stay on aspirin, but if the score is higher (2 or greater) the clinicians should consider continuing DAPT out to an additional 18 months (30 months total).
After entering all relevant data, clinicians should tap on the 'Complete Results' button below the calculator to get the final score and results explained in detail.
The results will show the patient's score and predicted event rates for both cases (if DAPT continued and discontinued), i.e. the percentage of risk for myocardial infarction (MI) and stent thrombosis, major adverse cardiovascular and cerebrovascular events (MACCE), and bleeding.
The app would also display a risk difference of continued DAPT treatment minus discontinued treatment for 12-30 months.
The DAPT Risk Calculator app also provides links to resources used for the app development, where users can learn more about the DAPT study and calculator, how DAPT score is used to predict adverse events, and more.
Overall, the DAPT Risk Calculator is another great app made by ACC, aimed to assist clinicians in managing patients who may require DAPT treatment after stent placement.
The app provides an easy to use, evidence-based calculator for evaluating the continuation of a dual antiplatelet therapy at the point of care.
The app is available for free on both iOS and Android platforms.
Benefit: Any provider who manages patients on antiplatelet agents would benefit from this app