NSTEACS

Non-ST-elevation acute coronary syndromes (NSTEACS) describe acute coronary syndromes without persistent ST-segment elevation on electrocardiography. The umbrella term includes unstable angina (UA) and non-ST-elevation myocardial infarction (NSTEMI). Both conditions result from rupture or erosion of a vulnerable atherosclerotic plaque with partial or transient coronary occlusion and thrombus formation.

Clinical presentation is similar to other ACS, with chest discomfort or dyspnea, sometimes radiation to the arm or jaw. The ECG may show ST-segment depression or T-wave inversion, but not persistent ST elevations. Serial measurements of cardiac troponin distinguish NSTEMI (troponin positive) from UA (troponin not elevated).

Risk is assessed with scores such as TIMI or GRACE to guide therapy. Management begins with stabilization and anti-ischemic measures (nitrates, beta-blockers, analgesia) and high-intensity statin therapy. Antiplatelet therapy, typically aspirin plus a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel), and anticoagulation (heparin or enoxaparin) are given. Patients with UA/NSTEMI often undergo an early invasive strategy with coronary angiography and possible PCI or CABG based on risk.

Timing of angiography: high-risk NSTEMI generally within 24 hours; intermediate risk within 24-48 hours; low-risk patients may be managed medically with monitoring and staged angiography as needed.

Secondary prevention includes lifestyle modification, smoking cessation, blood pressure and lipid control, diabetes management, and continuation of antiplatelet therapy for an indicated duration after ACS.