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Latest revision as of 20:17, 13 August 2022

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dima Nimri, M.D. [2]

Overview

Dual antiplatelet therapy (or DAPT) refers to the combination of aspirin and a P2Y12 receptor antagonist. DAPT is approved for SIHD and interventions for ACS, such as stent placement following PCI or CABG. The duration of treatment with DAPT for each of these categories differs and guidelines for treatment have been updated in the 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease. Much of the studies done on DAPT compared the use of different types of P2Y12 receptor antagonists, the dosage of drugs, as well as the duration of treatment. While the use of DAPT is associated with decreased risk of stent thrombosis, the benefits of treatment should be weighed against the increased risk of major bleeding.

Superiority of Dual Antiplatelet Therapy (Thienopyridine Plus Aspirin) Over Coumadin Plus Aspirin in PCI Patients

Several studies during the early stent era demonstrated the superiority of the combination of ticlopidine plus aspirin over coumadin plus aspirin. has deployment. While progress was made over coumadin, Ticlopidine itself was associated with side effects and complications which included neutropenia in > 1%, thrombotic thrombocytopenia purpura in 0.2%, rash, nausea and diarrhea. Given the improved side effect profile and the results of the CLASSICS study, clopidogrel has replaced ticlopidine as the thienopyridine of choice.

Data Indicating that the Addition of Aspirin to a Thienopyridine Improves Clinical Outcomes in Patients with Acute Coronary Syndromes

There is surrogate marker data indicating that the level of platelet inhibition is greater among patients in whom aspirin is added to a thienopyridine. In one study, aspirin added to clopidogrel was associated with a greater degree of inhibition of collagen-induced aggregation. The level of platelet aggregation for the combination was only 16.4 +/- 2.4%, which is less than that for aspirin alone (36.5 +/- 4.2%) or clopidogrel alone (59.3 +/- 5.1%, 3 way p < 0.001). Further, aspirin added to clopidogrel was more effective than either aspirin or clopidogrel alone after activation with low dose thrombin (p < 0.05). In rabbit models of stent thrombosis, aspirin potentiated the antithrombotic activity of clopidogrel in the following models: 1)thrombosis induced by a silk thread; 2) thrombosis in stents placed in an arteriovenous shunt; 3) thrombus formation following electrical stimulation of the rabbit carotid artery; and 4) 111 In-labeled platelet deposition on a stent implanted in an arteriovenous shunt. The clinical benefit of adding aspirin to clopidogrel is also demonstrated indirectly by the following observation: among patients on clopidogrel, patients with stent thrombosis were more often resistant to aspirin.

DAPT in Aspirin Intolerant Patients

One question that arises among patients who have aspirin hypersensitivity is the safety and efficacy of thienopyridine monotherapy in the mangement of the PCI patient including those who have been stented. There is one single center, small randomized trial purporting to compare the safety and efficacy of thienopyridine monotherapy to that of thienopyridine plus aspirin. 378 stents were placed in 243 patients who were randomly assigned to treatment with either 2 x 250 mg of ticlopidine (n=121) or the combination of 2 x 250 mg ticlopidine + 100 mg aspirin (122 patients) daily. All patients received 500 mg of intravenous aspirin at the time of the procedure. Two hundred and thirty-seven patients (97.5%) were free from the primary endpoint of death, cardiac events and vascular access-site complications through three months with no differences between treatment groups. Although 2 stent thromboses were observed in the combined treatment group, none were observed in the ticlopidine monotherapy group. There are several important limitations to this study. One is the fact that all patients received a high (500 mg) intravenous aspirin during the PCI which would have led to significant levels of platelet inhibition over the next week due to irreversible acetylation and inhibition of prostaglandin H-synthase/cyclooxygenase. This is a period of high vulnerability to stent thrombosis and ischemic complications. Thus, this was not truly a study of thienopyridine monotherapy as all patients received intravenous aspirin. The study by Machraoui is also limited by its small sample size. Finally, the study administered ticlopidine, which is not a pro-drug and may be associated with a lower rate of hyporesponsiveness than clopidogrel. In patients with aspirin hypersensitivity or intolerance, aspirin desensitization may be done. There are currently no guidelines or recommendations for the use of dual P2Y12 inhibitors as an alternative for DAPT in patients with aspirin hypersensitivity or intolerance.

Types and Dosage of Drugs

Aspirin

Aspirin 81 mg once daily (range 75-100 mg) is used in all patients with Stable Ischemic Heart Disease (SIHD), stent placement following PCI or CABG. The use of aspirin should be continued indefinitely.

P2Y12 Inhibitors

There are several P2Y12 inhibitors currently on the market and they are given in the following doses:

Clopidogrel: 75 mg once daily
Ticagrelor: 90 mg once daily
Prasugrel: 10 mg once daily

The drug of choice and duration of treatment depends on the medical condition and current recommendations.

Recommendations

The 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease includes recommendations for ACS treated with medical therapy and/or PCI, ACS treated with CABG, as well as stable ischemic heart disease:

The use of DAPT in Stroke

The 2014 AHA/ASA Guidelines for the Prevention of Stroke in Patients With Stroke and Transient Ischemic Attack included the following updated recommendations for the use of DAPT in stroke patients:

Class IIb
1. The combination of aspirin and clopidogrel might be considered for initiation within 24 hours of a minor ischemic stroke or TIA and for continuation for 90 days (Level of Evidence: B)
2. For patients with a history of ischemic stroke or TIA, AF, and CAD, the usefulness of adding antiplatelet therapy to VKA therapy is uncertain for purposes of reducing the risk of ischemic cardiovascular and cerebrovascular events (Level of Evidence: C). Unstable angina and coronary artery stenting represent special circumstances in which management may warrant DAPT/VKA therapy.

Class III (Harm)
1. The combination of aspirin and clopidogrel, when initiated days to years after a minor stroke or TIA and continued for 2 to 3 years, increases the risk of hemorrhage relative to either agent alone and is not recommended for routine long-term secondary prevention after ischemic stroke or TIA(Level of Evidence: A)
2. Prasugrel should not be administered to patients with a prior history of stroke or TIA (Level of Evidence: B)

Pre-Procedural Use of DAPT

Unstable Angina/ NSTEMI

In patients with unstable angina/ NSTEMI undergoing PCI, the following are the guidlelines for the use of DAPT:

Class I
1. Patients with definite or likely UA/NSTEMI selected for an invasive approach should receive dual antiplatelet therapy (Level of Evidence: A). Aspirin should be initiated on presentation (Level of Evidence: A), clopidogrel (before or at the time of PCI) (Level of Evidence: A) or prasugrel (at the time of PCI) (Level of Evidence: B) is recommended as a second antiplatelet agent.'

STEMI

In patients with STEMI undergoing PCI, the following are the guidelines for the use of DAPT:

Class I
1. After PCI, aspirin should be continued indefinitely.(Level of Evidence: A)
2. Clopidogrel should be provided as follows:
a. A 300-mg loading dose should be given before or at the time of PCI to patients who did not receive a previous loading dose and who are undergoing PCI within 24 hours of receiving fibrinolytic therapy (Level of Evidence: C) ;
b. A 600-mg loading dose should be given before or at the time of PCI to patients who did not receive a previous loading dose and who are undergoing PCI more than 24 hours after receiving fibrinolytic therapy (Level of Evidence: C) ; and
c. A dose of 75 mg daily should be given after PCI.(Level of Evidence: C)

Post-Procedural Duration of DAPT

Short-Term Use of DAPT

The risk of thrombotic events is highest during the first few weeks to months after PCI. In addition, premature cessation of DAPT is an independent risk factor for stent thrombosis, with the risk being highest in the first 6 months following PCI. While the optimal duration after PCI and DES implantation remains unclear, the decision to continue therapy beyond standard recommendations should be tailored according to patient's risk factors for bleeding, as well as type of stent used. A shorter duration of DAPT treatment means less bleeding. However, no significant difference in major adverse cardiac events (MACE) exists between short (3-6 months) and long (≥12 months) term duration of DAPT. An ST segment elevation MI following DES implantation beyond 6 months may be a complex and multifactorial phenomenon, which may not be solely related to the discontinuation of thienopyridine therapy.

The Leaders Free Trial

The Leaders Free Trial looks at the use of a very short duration of DAPT in patients with high bleeding risk following PCI and the insertion of a stent. Patients with a high bleeding risk are often times excluded from clinical trials on PCI and anti-thrombotic therapy. In this trial, high bleeding risk patients were given 1 month of DAPT following PCI and the insertion of either a bare metal stent (BMS) or a drug-coated stent (DCS) and were followed up for a period of two years. While it was initially thought that bare metal stents are superior to other types of stents in patients with high bleeding risk, the results of the Leaders Free Trial suggest that the incidence of coronary thrombotic events in patients who received a drug-coated stent were lower than those who received a bare metal stent, with no significant difference in the incidence of major bleeding between the two groups.

Long-Term Use of DAPT

The DAPT score

The DAPT score is a risk score derived from the DAPT Trial. It has been designed as a helpful tool for the continuation of dual antiplatelet therapy following PCI and the insertion of a drug-eluting stent (DES).

@@ Line 1: / Line 1: @@
+__NOTOC__
 {{SI}}
+{{CMG}}; {{AE}}{{DN}}
-{{CMG}}
+==Overview==
+Dual [[antiplatelet therapy]] (or DAPT) refers to the combination of [[aspirin]] and a [[P2Y12]] receptor antagonist. DAPT is approved for [[SIHD]] and interventions for [[ACS]], such as stent placement following [[PCI]] or [[CABG]]. The duration of treatment with DAPT for each of these categories differs and guidelines for treatment have been updated in the ''2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease''. Much of the studies done on DAPT compared the use of different types of [[P2Y12]] receptor antagonists, the dosage of drugs, as well as the duration of treatment. While the use of DAPT is associated with decreased risk of [[stent thrombosis]], the benefits of treatment should be weighed against the increased risk of major [[bleeding]].
 ==Superiority of Dual Antiplatelet Therapy (Thienopyridine Plus Aspirin) Over Coumadin Plus Aspirin in PCI Patients==
-Several studies during the early stent era demonstrated the superiority of the combination of [[ticlopidine]] plus [[aspirin]] over [[coumadin]] plus aspirin. has deployment <ref>Hall P, Nakamura S, Maiello L, et al. A randomized comparison of combined ticlopidine and aspirin therapy versus aspirin therapy alone after successful intravascular ultrasound-guided stent implantation. Circulation 1996;93:215-222.</ref><ref>Urban P, Macayo C, Rupprecht HJ, et al. Randomized evaluation of anticoagulation versus antiplatelet therapy after coronary stent implantation in high-risk patients: The multicenter aspirin and ticlopidine trial after intracoronary stenting (MATIS). Circulation 1998;98:2126-2132.</ref><ref>Schömig A, Neumann FJ, Kastrati A, et al. A randomized comparison of antiplatelet and anticoagulant therapy after the placement of coronary-artery stents. N Engl J Med 1996;334:1084-1089.</ref><ref>Leon MG, Baim DS, Popma JJ, et al. A clinical trial comparing three antithrombotic-drug regimens after coronary-artery stenting. Stent Anticoagulation Restenosis Study Investigators. N Engl J Med 1998;339:1665-1667.</ref><ref>Bertrand ME, Legrand V, Boland J, et al. Randomized multicenter comparison of conventional anticoagulation versus antiplatelet therapy in unplanned and elective coronary stenting. The full anticoagulation versus aspirin and ticlopidine (FANTASTIC) study. Circulation 1998;98:1597-1603.</ref>. While progress was made over coumadin, Ticlopidine itself was associated with side effects and complications which included [[neutropenia]] in > 1%, [[thrombotic thrombocytopenia purpura]] in 0.2%, rash, [[nausea]]and [[diarrhea]]<ref>Steinhubl SR, Tan WA, Foody JM, et al., for the EPISTENT Investigators. Incidence and clinical course of thrombotic thrombocytopenic purpura due to ticlopidine following coronary stenting. JAMA 1999;281:806-810.</ref>. Given the improved side effect profile and the results of the CLASSICS study, clopidogrel has replaced ticlopidine as the thienopyridine of choice <ref>Bertrand ME, Hans-Jürgen R, et al., for the CLASSICS Investigators. Double-blind study of the safety of clopidogrel with and without a loading dose in combination with aspirin compared with ticlopidine in combination with aspirin after coronary stenting. Circulation 2000;102:624-629.</ref><ref>Mueller C, Buttner JH, Petrerson J, et al. A randomized comparison of clopidogrel and aspirin versus ticlopidine and aspirin after the placement of coronary-artery stents. Circulation 2000;101:590-593.</ref><ref>Taniuchi M, Kurz HI, Smith SC, et al. Ticlid or Plavix Post-Stents (TOPPS) (Abstr). Circulation 1999;100(Suppl I):I-379</ref>.
+Several studies during the early stent era demonstrated the superiority of the combination of [[ticlopidine]] plus [[aspirin]] over [[coumadin]] plus aspirin. has deployment. While progress was made over [[Warfarin|coumadin]], [[Ticlopidine]] itself was associated with side effects and complications which included [[neutropenia]] in > 1%, thrombotic thrombocytopenia purpura in 0.2%, rash, [[nausea ]] and [[diarrhea]]. Given the improved side effect profile and the results of the CLASSICS study, [[clopidogrel]] has replaced [[ticlopidine]] as the [[thienopyridine]] of choice.
-==Data is Lacking Regarding the Safety and Efficacy of Thienopyridine Monotherapy Versus Thienopyridine Plus Aspirin Therapy in the Aspirin Intolerant Patient==
+==Data Indicating that the Addition of Aspirin to a Thienopyridine Improves Clinical Outcomes in Patients with Acute Coronary Syndromes==
-One question that arises among patients who have [[aspirin hypersensitivity]] is the safety and efficacy of thienopyridine monotherapy in the mangement of the PCI patient including those who have been stented.  There is one single center, small randomized trial purporting to compare the safety and efficacy of thienopyridine monotherapy to that of thienopyridine plus aspirin<ref>Machraoui A, Germing A, Lindstaedt M, et al. Efficacy and safety of ticlopidine monotherapy versus ticlopidine and aspirin after coronary artery stenting. Follow-up results of a randomized study. J Invas Cardiol 2001;13:431-436.</ref>. 378 stents were placed in 243 patients who were randomly assigned to treatment with either 2 x 250 mg of ticlopidine (n=121) or the combination of 2 x 250 mg ticlopidine + 100 mg aspirin (122 patients) daily. '''''All patients received 500 mg of intravenous aspirin at the time of the procedure.'''''  Two hundred and thirty-seven patients (97.5%) were free from the primary endpoint of death, cardiac events and vascular access-site complications through three months with no differences between treatment groups. Although 2 stent thromboses were observed in the combined treatment group, none were observed in the ticlopidine monotherapy group. There are several important limitations to this study. One is the fact that all patients received a high (500 mg) intravenous aspirin during the PCI which would have led to significant levels of platelet inhibition over the next week due to irreversible acetylation and inhibition of prostaglandin H-synthase/[[cyclooxygenase]]<ref>Awtry EH, Loscalzo J. Aspirin. Cardiovascular Drugs. Circulation 2000;101:1206-1218.</ref>. This is a period of high vulnerability to stent thrombosis and ischemic complications<ref>Wilson S, Rihal CS, Bell MR, et al. Timing of coronary stent thrombosis in patients treated with ticlopidine and aspirin. Am J Cardiol 1999;83:1006-1011.</ref>. Thus, this was not truly a study of thienopyridine monotherapy as all patients received intravenous aspirin. The study by Machraoui is also limited by its small sample size.  Finally, the study administered [[ticlopidine]], which is not a pro-drug and may be associated with a lower rate of hyporesponsiveness than clopidogrel.
+There is surrogate marker data indicating that the level of [[platelet]] inhibition is greater among patients in whom [[aspirin]] is added to a [[thienopyridine]]. In one study, aspirin added to [[clopidogrel]] was associated with a greater degree of inhibition of collagen-induced aggregation. The level of [[platelet aggregation]] for the combination was only 16.4 +/- 2.4%, which is less than that for [[aspirin]] alone (36.5 +/- 4.2%) or [[clopidogrel]] alone (59.3 +/- 5.1%, 3 way p < 0.001).  Further, aspirin added to clopidogrel was more effective than either aspirin or clopidogrel alone after activation with low dose thrombin (p < 0.05).  In rabbit models of [[stent thrombosis]], aspirin potentiated the [[antithrombotic]] activity of clopidogrel in the following models: 1)[[thrombosis]] induced by a silk thread; 2) thrombosis in stents placed in an [[Arteriovenous shunts|arteriovenous shunt]]; 3) thrombus formation following electrical stimulation of the rabbit [[carotid artery]]; and 4) 111 In-labeled platelet deposition on a stent implanted in an [[Arteriovenous shunts|arteriovenous shunt]]. The clinical benefit of adding aspirin to clopidogrel is also demonstrated indirectly by the following observation: among patients on clopidogrel, patients with stent thrombosis were more often resistant to [[aspirin]].
-==Data Inidicating that the Addition of Aspirin to a Thienopyridine Improves Clinical Outcomes in Patients with Acute Coronary Syndromes==
+==DAPT in Aspirin Intolerant Patients==
-There is surrogate marker data indicating that the level of platelet inhibition is greater among patients in whom aspirin is added to a thienopyridine.<ref>Makkar RR, Eigler NL, Kaul S, et al. Effects of clopidogrel, aspirin and combined therapy in a porcine ex vivo model of high-shear induced stent thrombosis. Eur Heart J 1998;10:1538-1546.</ref><ref>Moshfegh K, Redondo M, Julmy F, et al. Antiplatelet effects of clopidogrel compared with aspirin after myocardial infarction: Enhanced inhibitory effects of combination therapy. J Am Coll Cardiol 2000;36:699-705.</ref><ref>Cadroy Y, Bossavy J, Thalamas C, et al. Early potent antithrombotic effect with combined aspirin and a loading dose of clopidogrel on experimental arterial thrombogenesis in humans. Circulation 2000;101:2823-2828.</ref> In one study, aspirin added to clopidogrel was associated with a greater degree of inhibition of collagen-induced aggregation. The level of platelet aggregation for the combination was only 16.4 +/- 2.4%, which is less than that for aspirin alone (36.5 +/- 4.2%) or clopidogrel alone (59.3 +/- 5.1%, 3 way p < 0.001).<ref>Moshfegh K, Redondo M, Julmy F, et al. Antiplatelet effects of clopidogrel compared with aspirin after myocardial infarction: Enhanced inhibitory effects of combination therapy. J Am Coll Cardiol 2000;36:699-705.</ref>  Further, aspirin added to clopidogrel was more effective than either aspirin or clopidogrel alone after activation with low dose thrombin (p < 0.05).<ref>Moshfegh K, Redondo M, Julmy F, et al. Antiplatelet effects of clopidogrel compared with aspirin after myocardial infarction: Enhanced inhibitory effects of combination therapy. J Am Coll Cardiol 2000;36:699-705.</ref>  In rabbit models of stent thrombosis, aspirin potentiated the antithrombotic activity of clopidogrel in the following models: 1)thrombosis induced by a silk thread; 2) thrombosis in stents placed in an arteriovenous shunt; 3) thrombus formation following electrical stimulation of the rabbit carotid artery; and 4) 111In-labeled platelet deposition on a stent implanted in an arteriovenous shunt.<ref name="pmid9759636">{{cite journal |author=Herbert JM, Dol F, Bernat A, Falotico R, Lalé A, Savi P |title=The antiaggregating and antithrombotic activity of clopidogrel is potentiated by aspirin in several experimental models in the rabbit |journal=[[Thrombosis and Haemostasis]] |volume=80 |issue=3 |pages=512–8 |year=1998 |month=September |pmid=9759636 |doi= |url=http://www.schattauer.de/index.php?id=1268&L=1&pii=th98090512&no_cache=1 |issn= |accessdate=2010-07-02}}</ref>The clinical benefit of adding aspirin to clopidogrel is also demonstrated indirectly by the following observation: among patients on clopidogrel, patients with stent thrombosis were more often resistant to aspirin<ref name="pmid20435201">{{cite journal |author=Eshtehardi P, Windecker S, Cook S, Billinger M, Togni M, Garachemani A, Meier B, Hess OM, Wenaweser P |title=Dual low response to acetylsalicylic acid and clopidogrel is associated with myonecrosis and stent thrombosis after coronary stent implantation |journal=[[American Heart Journal]] |volume=159 |issue=5 |pages=891–898.e1 |year=2010 |month=May |pmid=20435201 |doi=10.1016/j.ahj.2010.02.025 |url=http://linkinghub.elsevier.com/retrieve/pii/S0002-8703(10)00169-9 |issn= |accessdate=2010-07-02}}</ref><ref name="pmid16237868">{{cite journal |author=Wenaweser P, Hess O |title=Stent thrombosis is associated with an impaired response to antiplatelet therapy |journal=[[Journal of the American College of Cardiology]] |volume=46 |issue=5 |pages=CS5–6 |year=2005 |month=September |pmid=16237868 |doi= |url= |issn= |accessdate=2010-07-02}}</ref>
+One question that arises among patients who have [[aspirin hypersensitivity]] is the safety and efficacy of [[thienopyridine]] monotherapy in the mangement of the [[PCI]] patient including those who have been stented.  There is one single center, small randomized trial purporting to compare the safety and efficacy of thienopyridine monotherapy to that of thienopyridine plus aspirin. 378 stents were placed in 243 patients who were randomly assigned to treatment with either 2 x 250 mg of ticlopidine (n=121) or the combination of 2 x 250 mg ticlopidine + 100 mg aspirin (122 patients) daily. '''''All patients received 500 mg of intravenous aspirin at the time of the procedure.'''''  Two hundred and thirty-seven patients (97.5%) were free from the primary endpoint of death, cardiac events and vascular access-site complications through three months with no differences between treatment groups. Although 2 stent thromboses were observed in the combined treatment group, none were observed in the ticlopidine monotherapy group. There are several important limitations to this study. One is the fact that all patients received a high (500 mg) intravenous aspirin during the [[PCI]] which would have led to significant levels of [[platelet]] inhibition over the next week due to irreversible [[acetylation]] and inhibition of prostaglandin H-synthase/[[cyclooxygenase]]. This is a period of high vulnerability to [[stent thrombosis]] and ischemic complications. Thus, this was not truly a study of [[thienopyridine]] monotherapy as all patients received intravenous aspirin. The study by Machraoui is also limited by its small sample size.  Finally, the study administered [[ticlopidine]], which is not a pro-drug and may be associated with a lower rate of hyporesponsiveness than [[clopidogrel]]. In patients with [[aspirin]] hypersensitivity or intolerance, [[aspirin]] desensitization may be done. There are currently no guidelines or recommendations for the use of dual [[P2Y12]] inhibitors as an alternative for DAPT in patients with [[aspirin]] hypersensitivity or intolerance.
-==References==
+== Types and Dosage of Drugs ==
-{{reflist|2}}
+===Aspirin===
+[[Aspirin]] 81 mg once daily (range 75-100 mg) is used in all patients with Stable Ischemic Heart Disease ([[SIHD]]), stent placement following [[PCI]] or [[CABG]]. The use of [[aspirin]] should be continued indefinitely.
+===P2Y12 Inhibitors===
+There are several [[P2Y12]] inhibitors currently on the market and they are given in the following doses:
+*[[Clopidogrel]]: 75 mg once daily
+*[[Ticagrelor]]: 90 mg once daily
+*[[Prasugrel]]: 10 mg once daily
-[[Category:Cardiology]]
+The drug of choice and duration of treatment depends on the medical condition and current recommendations.
-[[Category:Drugs]]
-{{WH}}
+==Recommendations==
-{{WS}}
+The 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease includes recommendations for [[ACS]] treated with medical therapy and/or [[PCI]], [[ACS]] treated with [[CABG]], as well as [[stable ischemic heart disease]]:
+*[[Unstable angina/NSTEMI Antiplatelet therapy recommendations#2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease (Updating the 2014 AHA/ACC Guideline for the Management of Patients With Non–ST-Elevation Acute Coronary Syndromes (DO NOT EDIT))|Unstable Angina/ NSTEMI Treated with Medical Therapy Alone]]
+*[[ST elevation myocardial infarction anticoagulant and antithrombotic therapy#2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease|STEMI Treated with Medical Therapy Alone]]
+*[[Pharmacotherapy to Support PCI#2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease|Following PCI]]
+*[[Unstable angina / non ST-elevation myocardial infarction recommendations for CABG#2016 ACC/AHA guideline focused update on a duration of antiplatelet therapy in patients with coronary artery disease|CABG for NSTEMI]]
+*[[ST elevation myocardial infarction coronary artery bypass grafting#2016 ACC/AHA guideline focused update on a duration of dual antiplatelet therapy in patients with coronary artery disease|CABG for STEMI]]
+*[[Chronic stable angina revascularization adjunctive pharmacotherapy for percutaneous coronary intervention#2016 ACC/AHA Guideline focused update on a duration of dual antiplatelet therapy (DAPT) in Patients with coronary artery disease|Stable Ischemic Heart Disease]]
+==The use of DAPT in Stroke==
+''The 2014 AHA/ASA Guidelines for the Prevention of Stroke in Patients With Stroke and Transient Ischemic Attack'' included the following updated recommendations for the use of DAPT in stroke patients:
+{| class="wikitable" style="width:80%"
+|-
+| colspan="1" style="text-align:center; background:LemonChiffon" |[[ACC AHA guidelines classification scheme#Classification of Recommendations|Class IIb]]
+|-
+| bgcolor="LemonChiffon" |'''1.''' The combination of aspirin and clopidogrel might be considered for initiation within 24 hours of a minor ischemic stroke or TIA and for continuation for 90 days ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: B]])''
+|-
+| bgcolor="LemonChiffon" |'''2.''' For patients with a history of ischemic stroke or TIA, AF, and CAD, the usefulness of adding antiplatelet therapy to VKA therapy is uncertain for purposes of reducing the risk of ischemic cardiovascular and cerebrovascular events ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: C]])''. Unstable angina and coronary artery stenting represent special circumstances in which management may warrant DAPT/VKA therapy.
+|-
+|}
+{| class="wikitable" style="width:80%"
+|-
+| colspan="1" style="text-align:center; background:LightCoral" |[[ACC AHA guidelines classification scheme#Classification of Recommendations|Class III]] (Harm)
+|-
+| bgcolor="LightCoral" |'''1.''' The combination of aspirin and clopidogrel, when initiated days to years after a minor stroke or TIA and continued for 2 to 3 years, increases the risk of hemorrhage relative to either agent alone and is not recommended for routine long-term secondary prevention after ischemic stroke or TIA''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: A]])''
+|-
+| bgcolor="LightCoral" |'''2.''' Prasugrel should not be administered to patients with a prior history of stroke or TIA ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: B]])''
+|-
+|}
+==Pre-Procedural Use of DAPT==
+===Unstable Angina/ NSTEMI===
+In patients with unstable angina/ NSTEMI undergoing [[PCI]], the following are the guidlelines for the use of DAPT:
+{| class="wikitable"
+|-
+| colspan="1" style="text-align:center; background:LightGreen" |[[ACC AHA guidelines classification scheme#Classification of Recommendations|Class I]]
+|-
+| bgcolor="LightGreen" |'''1.''' Patients with definite or likely [[UA]]/[[NSTEMI]] selected for an invasive approach should receive [[dual antiplatelet therapy]] ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: A]])''. [[Aspirin]] should be initiated on presentation ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: A]])'', [[clopidogrel]] (before or at the time of PCI) ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: A]])'' or [[prasugrel]] (at the time of PCI) ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: B]])'' is recommended as a second [[antiplatelet]] agent.''''
+|}
+===STEMI===
+In patients with [[STEMI]] undergoing [[PCI]], the following are the guidelines for the use of DAPT:
+{| class="wikitable"
+|-
+| colspan="1" style="text-align:center; background:LightGreen" |[[ACC AHA guidelines classification scheme#Classification of Recommendations|Class I]]
+|-
+| bgcolor="LightGreen" |'''1.''' After PCI, aspirin should be continued indefinitely.''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: A]]) ''
+|-
+| bgcolor="LightGreen" |'''2.''' [[Clopidogrel]] should be provided as follows:
+|-
+| bgcolor="LightGreen" |'''a.''' A 300-mg loading dose should be given before or at the time of PCI to patients who did not receive a previous loading dose and who are undergoing [[PCI]] within 24 hours of receiving fibrinolytic therapy ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: C]])'' ;
+|-
+| bgcolor="LightGreen" |'''b.''' A 600-mg loading dose should be given before or at the time of PCI to patients who did not receive a previous loading dose and who are undergoing PCI more than 24 hours after receiving fibrinolytic therapy ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: C]])'' ; and
+|-
+| bgcolor="LightGreen" |'''c.''' A dose of 75 mg daily should be given after PCI.''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: C]])''
+|}
+==Post-Procedural Duration of DAPT==
+===Short-Term Use of DAPT===
+The risk of thrombotic events is highest during the first few weeks to months after [[PCI]]. In addition, premature cessation of DAPT is an independent risk factor for [[stent thrombosis]], with the risk being highest in the first 6 months following [[PCI]]. While the optimal duration after [[PCI]] and [[DES]] implantation remains unclear, the decision to continue therapy beyond standard recommendations should be tailored according to patient's risk factors for [[bleeding]], as well as type of stent used. A shorter duration of DAPT treatment means less bleeding. However, no significant difference in major adverse cardiac events (MACE) exists between short (3-6 months) and long (≥12 months) term duration of DAPT. An [[ST segment elevation MI]] following [[DES]] implantation beyond 6 months may be a complex and multifactorial phenomenon, which may not be solely related to the discontinuation of thienopyridine therapy.
+=== The Leaders Free Trial ===
+The ''Leaders Free Trial'' looks at the use of a very short duration of DAPT in patients with high bleeding risk following [[PCI]] and the insertion of a stent. Patients with a high bleeding risk are often times excluded from clinical trials on [[Percutaneous coronary intervention|PCI]] and [[Antithrombotic therapy|anti-thrombotic therapy]]. In this trial, high bleeding risk patients were given 1 month of DAPT following [[PCI]] and the insertion of either a [[bare metal stent]] ([[BMS]]) or a drug-coated stent (DCS) and were followed up for a period of two years. While it was initially thought that [[bare metal stent|bare metal stents]] are superior to other types of stents in patients with high bleeding risk, the results of the ''Leaders Free Trial'' suggest that the incidence of coronary thrombotic events in patients who received a drug-coated stent were lower than those who received a [[bare metal stent]], with no significant difference in the incidence of major bleeding between the two groups.
+===Long-Term Use of DAPT===
+====The DAPT score====
+The DAPT score is a risk score derived from the DAPT Trial. It has been designed as a helpful tool for the continuation of dual antiplatelet therapy following [[PCI]] and the insertion of a drug-eluting stent ([[DES]]).