4/17/2021 0 Comments Class Iii Angina
Unfractionated heparin is more complicated to use because it requires frequent (every 6 hours) dosing adjustments to achieve target activated partial thromboplastin time (aPTT).Symptoms include chest discomfort with or without dyspnea, nausea, and diaphoresis.Diagnosis is by ECG and the presence or absence of serologic markers.
Treatment is with antiplatelet drugs, anticoagulants, nitrates, statins, and beta-blockers. Coronary angiography with percutaneous intervention or coronary artery bypass surgery is often necessary. Also considered are whether unstable angina occurs during treatment for chronic stable angina and whether transient changes in ST-T waves occur during angina. If angina has occurred within 48 hours and no contributory extracardiac condition is present, troponin levels may be measured to help estimate prognosis; troponin-negative results indicate a better prognosis than troponin-positive. Also, urgent cardiac catheterization is indicated for patients with acute STEMI but not generally for those with NSTEMI or unstable angina. ECG changes such as ST-segment depression, ST-segment elevation, or T-wave inversion may occur during unstable angina but are transient. Coronary angiography most often combines diagnosis with percutaneous coronary intervention (PCIie, angioplasty, stent placement). For example, stenosis of the proximal left main artery or equivalent (proximal left arterial descending and circumflex artery stenosis) has a worse prognosis than does distal stenosis or stenosis in a smaller arterial branch. Left ventricular function also greatly influences prognosis; patients with significant left ventricular dysfunction (even those with 1- or 2-vessel disease) have a lower threshold for revascularization. Prehospital interventions by emergency medical personnel (including ECG, chewed aspirin 325 mg, pain management with nitrates) can reduce risk of mortality and complications. Early diagnostic data and response to treatment can help determine the need for and timing of revascularization. Drug therapy and timing of revascularization depend on the clinical picture. In clinically unstable patients (patients with ongoing symptoms, hypotension or sustained arrhythmias), urgent angiography with revascularization is indicated. In clinically stable patients, angiography with revascularization may be deferred for 24 to 48 hours (see figure Approach to unstable angina ). New data suggest that morphine attenuates activity of some P2Y12 receptor inhibitors and may contribute to worse patient outcomes. The specific drugs used depend on the reperfusion strategy and other factors; their selection and use is discussed in Drugs for Acute Coronary Syndrome. Other drugs, such as beta-blockers, ACE inhibitors, and statins, should be initiated during admission (see table Drugs for Coronary Artery Disease ). Chewing the first dose before swallowing quickens absorption. In patients undergoing PCI, a loading dose of clopidogrel (300 to 600 mg orally once), prasugrel (60 mg orally once), or ticagrelor (180 mg orally once) improves outcomes, particularly when administered 24 hours in advance. For urgent PCI, prasugrel and ticagrelor are more rapid in onset and may be preferred.
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