Unstable angina / non ST elevation myocardial infarction recommendations for PCI


 * Associate Editors-In-Chief: Smita Kohli, M.D.; Varun Kumar, M.B.B.S.; Lakshmi Gopalakrishnan, M.B.B.S.

Overview of Recommendations for Percutaneous coronary intervention (PCI) in Unstable angina/NSTEMI

 * Coronary angiography is useful for defining the coronary artery anatomy in patients with UA/NSTEMI and for identifying subsets of high-risk patients who can benefit from early revascularization. The benefits of early invasive strategy have been discussed in previous section (see Initial Conservative Versus Initial Invasive Strategies).
 * Coronary revascularization with either PCI or CABG helps improve prognosis, relieve symptoms, prevent ischemic complications, and improve functional capacity. In recent years, increased utilization of PCI has been noticed mainly secondary to technical advancements and as a result of this, less complications associated with the procedure.
 * PCI term refers to the whole group of percutaneous techniques, including standard balloon angioplasty (PTCA), intracoronary stenting, and atheroablative technologies(like atherectomy, thrombectomy, or laser angioplasty). Today, majority of PCIs involve balloon dilation and coronary stenting.
 * Two main classes of stents available currently include bare metal stent and drug eluting stents. Drug eluting stents have been demonstrated to markedly reduce the risk of restenosis compared with bare-metal stents.
 * With the increasing use of GP IIb/IIIa inhibitors, clopidogrel, and/or other antithrombotic drugs in UA/NSTEMI patients, complications related to PCI have decreased dramatically and both acute and long-term outcomes following PCI have improved with success rates as high as 95%.

==ACC / AHA Guidelines-Recommendations for PCI in patients with UA/NSTEMI (DO NOT EDIT) ==

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Class I
1. An early invasive PCI strategy is indicated for patients with UA / NSTEMI who have no serious comorbidity and who have coronary lesions amenable to PCI and any of the high risk features.

2. Percutaneous coronary intervention (or CABG) is recommended for UA / NSTEMI patients with 1 or 2 vessel CAD with or without significant proximal left anterior descending CAD but with a large area of viable myocardium and high risk criteria on non invasive testing. (Level of Evidence: B)

3. Percutaneous coronary intervention (or CABG) is recommended for UA/NSTEMI patients with multi vessel coronary disease with suitable coronary anatomy, with normal LV function, and without diabetes mellitus. (Level of Evidence: A)

4. An intravenous platelet GP IIb/IIIa inhibitor is generally recommended in UA/NSTEMI patients undergoing PCI. (Level of Evidence: A)

Class IIa
1. Percutaneous coronary intervention is reasonable for focal saphenous vein graft (SVG) lesions or multiple stenosis in UA / NSTEMI patients who are undergoing medical therapy and who are poor candidates for reoperative surgery. (Level of Evidence: C)

2. Percutaneous coronary intervention (or CABG) is reasonable for UA / NSTEMI patients with 1 or 2 vessel CAD with or without significant proximal left anterior descending CAD but with a moderate area of viable myocardium and ischemia on noninvasive testing. (Level of Evidence: B)

3. Percutaneous coronary intervention (or CABG) can be beneficial compared with medical therapy for UA / NSTEMI patients with 1 vessel disease with significant proximal left anterior descending CAD. (Level of Evidence: B)

4. Use of PCI is reasonable in patients with UA / NSTEMI with significant left main CAD (>50% diameter stenosis) who are candidates for revascularization but are not eligible for CABG or who require emergent intervention at angiography for hemodynamic instability. (Level of Evidence: B)

Class IIb
1. In the absence of high-risk features associated with UA / NSTEMI, PCI may be considered in patients with single-vessel or multi vessel CAD who are undergoing medical therapy and who have 1 or more lesions to be dilated with a reduced likelihood of success. (Level of Evidence: B)

2. Percutaneous coronary intervention may be considered for UA / NSTEMI patients who are undergoing medical therapy who have 2 or 3 vessel disease, significant proximal left anterior descending CAD, and treated diabetes or abnormal LV function, with anatomy suitable for catheter based therapy. (Level of Evidence: B)

Class III
1. Percutaneous coronary intervention (or CABG) is not recommended for patients with 1 or 2 vessel CAD without significant proximal left anterior descending CAD with no current symptoms or symptoms that are unlikely to be due to myocardial ischemia and who have no ischemia on noninvasive testing. (Level of Evidence: C)

2. In the absence of high risk features associated with UA / NSTEMI, PCI is not recommended for patients with UA / NSTEMI who have single vessel or multi vessel CAD and no trial of medical therapy, or who have one or more of the following:


 * a. Only a small area of myocardium at risk. (Level of Evidence: C)
 * b. All lesions or the culprit lesion to be dilated with morphology that conveys a low likelihood of success. (Level of Evidence: C)
 * c. A high risk of procedure related morbidity or mortality. (Level of Evidence: C)
 * d. Insignificant disease (<50% coronary stenosis). (Level of Evidence: C)
 * e. Significant left main CAD and candidacy for CABG. (Level of Evidence: B)

3. A PCI strategy in stable patients with persistently occluded infarct related coronary arteries after NSTEMI is not indicated. (Level of Evidence: B)}}

Platelet Inhibitors and PCI

 * Aspirin is one of the oldest platelet inhibitors and has been repeatedly shown to improve outcomes in CAD patients.
 * Thienopyridines (like clopidogrel, prasugrel, ticagrelor) are becoming increasingly important in PCI patients due to their benefit in reducing stent thrombosis.
 * Along with aspirin, thienopyridines (i.e. either prasugrel or clopidogrel) form the dual antiplatelet therapy that are now routinely recommended before or at the time of PCI.
 * An important advance in the treatment of patients with UA/NSTEMI who are undergoing PCI was the introduction of platelet GP IIb/IIIa receptor inhibitors(like abciximab, tirofiban, eptifibatide) in the 1990s. All three GP IIb/IIIa inhibitors have been shown to reduce the incidence of ischemic complications in patients with UA/NSTEMI.
 * Abciximab is not recommended if PCI is not planned.

Clinical trial data:
Multiple randomized trials have previously shown good outcomes with the use of GP IIb/IIIa inhibitors in UA/NSTEMI patients but some recent trials ave also shown that these results may be confined to high risk groups and those with troponin elevations.
 * EARLY ACS trial revealed that in patients who had acute coronary syndromes without ST-segment elevation, the use of eptifibatide 12 hours or more before angiography was not superior to the provisional use of eptifibatide after angiography. The early use of eptifibatide was associated with an increased risk of non-life-threatening bleeding and need for transfusion.
 * ISAR-REACT 2 trial studied abciximab in NSTEMI patients. This was a multicenter, randomized, double-blind, placebo-controlled study enrolling 2022 patients with NSTEMI undergoing PCI. Results showed that abciximab reduces the risk of adverse events in patients with NSTEMI undergoing PCI after pretreatment with 600 mg of clopidogrel. The benefits provided by abciximab appear to be confined to patients presenting with an elevated troponin level. The benefit of GP IIb/IIIa inhibition appears greater when used in high-risk patients and in those with ST segment changes. The benefit was also seen in high risk patients with or without revascularization.
 * In the ACUITY trial superiority of early GP IIb/IIIa inhibitor therapy also was not found, but investigators could not exclude as much as a 29% benefit with GP IIb/IIIa therapy nor show non inferiority of delayed administration. In addition, drug exposure before angiography was much shorter (4 hours), which might substantially diminish the opportunity for differential efficacy. Despite a lack of clarity from the overall and subgroup results, an argument can be made against the routine upstream use of GP IIb/IIIa therapy in all NSTEMI patients intended for an invasive strategy. In particular, those with a normal baseline troponin level and those over the age of 75 years, in whom there was no evidence for benefit but who showed an increased risk of bleeding, might be excluded. On the other hand, high risk patients, diabetic patients and those with troponin elevation have been shown to have positive trends which go along with the results of previous trials. Although, this puts forward a debate to the routine early use of GP IIb/IIIa inhibitors in UA/NSTEMI patients, the current guidelines favor the use of GP IIb/IIIa inhibitors in patients undergoing PCI.

Also refer to the section on PCI.

==ACC/AHA Guidelines for the Timing of Angiography and Antiplatelet Therapy in UA/NSTEMI(DO NOT EDIT) ==

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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.

Class IIa
1. It is reasonable for initially stabilized high-risk patients with UA/NSTEMI (GRACE risk score greater than 140) to undergo an early invasive strategy within 12 to 24 hours of admission. For patients not at high risk, an early invasive approach is also reasonable. (Level of Evidence: B)}}