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C28 Cardiology and Cardiac Surgery
Ischemic Heart Disease Toronto Notes 2019
2. Anti-Platelet and Anticoagulation Therapy
■ see also CCS Antiplatelet Guidelines 2012 for details (free mobile apps available on iOS and Android
TIMI Risk Score for UA/NSTEMI
Characteristics
Historical
■ ■
■ ■
■
platforms in the CCS app stores) ASAchewed
NSTEMI
◆ ticagrelor in addition to ASA or if ASA contraindicated, subcutaneous low molecular weight heparin or IV unfractionated heparin (UFH) (LMWH preferable, except in renal failure or if CABG is planned within 24 h)
◆ clopidogrel used if patient ineligible for ticagrelor
if PCI is planned: ticagrelor or prasugrel and consider IV GP IIb/IIIa inhibitor (e.g. abciximab)
◆ clopidogrel used if patient ineligible for ticagrelor and prasugrel
◆ prasugel contraindicated in those with a history of stroke/TIA, and avoidance of or lower dose is
recommended for those >75 yr old or weighing under 60 kg (TRITON-TIMI 38) anticoagulation options depend on reperfusion strategy:
◆ primary PCI: UFH during procedure; bivalirudin is a possible alternative
◆ thrombolysis: LMWH (enoxaparin) until discharge from hospital; can use UFH as alternative
because of possible rescue PCI
◆ no reperfusion: LMWH (enoxaparin) until discharge from hospital
continue LMWH or UFH followed by oral anticoagulation at discharge if at high risk for thromboembolic event (large anterior MI, AFib, severe LV dysfunction, CHF, previous DVT or PE, or echo evidence of mural thrombus)
Points
1
1
Recent (≤24 h) severe angina 1 ST-segment deviation ≥0.5 mm 1 Increased cardiac markers 1
Risk Score = Total Points IfTIMIriskscore≥3,considerearlyLMWHand angiography
TIMI = thrombolysis in myocardial infarction UA = unstable angina
JAMA 2000;284:835-842
Newer, more accurate risk quantification scores for UA/NSTEMI exist, such as the GRACE Risk Score; however, TIMI is still used most often
Age ≥65 yr
≥3 risk factors for CAD
Known CAD (stenosis ≥50%) 1 Aspirin® use in past 7 d 1
Presentation
3. β-blockers
■ STEMI: contraindications include signs of heart failure, low output states, risk of cardiogenic shock, heart block, asthma or airway disease; initiate orally within 24 h of diagnosis when indicated
■ ifβ-blockersarecontraindicatedorifβ-blockers/nitratesfailtorelieveischemia,non- dihydropyridine calcium channel blockers (e.g. diltiazem, verapamil) may be used as second-line therapy in the absence of severe LV dysfunction or pulmonary vascular congestion (calcium channel blockers do not prevent MI or decrease mortality)
4. Invasive Strategies and Reperfusion Options
■ UA/NSTEMI: early coronary angiography ± revascularization if possible is recommended with any of the following high-risk indicators:
◆ recurrent angina/ischemia at rest despite intensive anti-ischemic therapy
◆ CHF or LV dysfunction
◆ hemodynamic instability
◆ high (≥3) TIMI risk score (tool used to estimate mortality following an ACS) ◆ sustained ventricular tachycardia
◆ dynamic ECG changes
◆ high-risk findings on non-invasive stress testing
◆ PCI within the previous 6 mo
◆ repeated presentations for ACS despite treatment and without evidence of ongoing ischemia or
high risk features
◆ note: thrombolysis is NOT administered for UA/NSTEMI
■ STEMI
◆ after diagnosis of STEMI is made, do not wait for results of further investigations before
implementing reperfusion therapy
◆ goal is to re-perfuse artery: thrombolysis (“EMS-to-needle”) within 30 min or primary PCI
(“EMS-to-balloon”) within 90 min (depending on capabilities of hospital and access to hospital
with PCI facility)
◆ thrombolysis
– preferred if patient presents ≤12 h of symptom onset, and <30 min after presentation to hospital, has contraindications to PCI, or PCI cannot be administered within 90 min
◆ PCI
– early PCI (≤12 h after symptom onset and <90 min after presentation) improves mortality
vs. thrombolysis with fewer intra-cranial hemorrhages and recurrent MIs
– primary PCI: without prior thrombolytic therapy – method of choice for reperfusion in
experienced centres (JAMA 2004;291:736-739)
– rescue PCI: following failed thrombolytic therapy (diagnosed when following thrombolysis,
ST segment elevation fails to resolve below half its initial magnitude and patient still having chest pain)