NSTEMI Management Guidelines
For managing Non-ST-Elevation Myocardial Infarction (NSTEMI), follow the ACC/AHA and ESC guidelines which provide comprehensive, evidence-based protocols covering initial emergency department triage, early hospital care, pharmacotherapy, risk stratification, and timing of invasive intervention. 1
Emergency Department and Initial Triage
Immediate Actions Upon Presentation
All patients with suspected NSTEMI must be treated as high-priority triage cases and placed on continuous cardiac monitoring immediately, with emergency resuscitation equipment and defibrillator nearby. 1
Obtain a 12-lead ECG within 10 minutes of ED arrival and have it evaluated by an experienced emergency medicine physician. 1
Measure high-sensitivity cardiac troponin at presentation (0 hours) and repeat at 3-6 hours after symptom onset, with additional testing beyond 6 hours if clinical suspicion remains high. 2
Administer supplemental oxygen only if arterial saturation is <90%, respiratory distress is present, or other high-risk features for hypoxemia exist (pulse oximetry should be used for continuous monitoring). 1
EMS and Pre-Hospital Considerations
Patients should call 9-1-1 and be transported by ambulance rather than private vehicle, as approximately 1 in 300 patients with chest pain transported by private vehicle develops cardiac arrest en route. 1
Every community must have a written protocol guiding EMS personnel on destination hospitals; patients with suspected ACS should go to the nearest appropriate hospital, while those with known STEMI or cardiogenic shock should be sent directly to hospitals with interventional and surgical capability. 1
Early Hospital Care and Monitoring
Admission and Monitoring Requirements
Admit all NSTEMI patients to a monitored unit (step-down unit or equivalent) with continuous ECG rhythm monitoring for at least 24 hours, or longer for patients at increased risk for cardiac arrhythmias. 1, 3
Bed/chair rest with continuous ECG monitoring is mandatory during the early hospital phase. 1
Anti-Ischemic Pharmacotherapy
Nitrates:
Administer sublingual nitroglycerin (0.4 mg) every 5 minutes for a total of 3 doses for ongoing ischemic discomfort, then assess need for intravenous nitroglycerin. 1
Intravenous nitroglycerin is indicated in the first 48 hours for treatment of persistent ischemia, heart failure, or hypertension, but should not preclude therapy with beta blockers or ACE inhibitors. 1
Beta-Blockers:
Initiate oral beta-blocker therapy within the first 24 hours unless the patient has: (1) signs of heart failure, (2) evidence of low-output state, (3) increased risk for cardiogenic shock, or (4) other contraindications (PR interval >0.24 seconds, second or third degree heart block, active asthma, or reactive airway disease). 1
Beta-blockers should be continued indefinitely for all patients recovering from NSTEMI unless contraindicated. 3
Calcium Channel Blockers:
- For patients with continuing or frequently recurring ischemia in whom beta blockers are contraindicated, administer a nondihydropyridine calcium channel blocker (verapamil or diltiazem) as initial therapy in the absence of clinically significant LV dysfunction. 1
ACE Inhibitors/ARBs:
Administer an ACE inhibitor orally within the first 24 hours to patients with pulmonary congestion or LVEF ≤0.40, in the absence of hypotension (systolic blood pressure <90 mmHg). 1
ACE inhibitors should be continued indefinitely for patients with heart failure, LV dysfunction (LVEF <0.40), hypertension, or diabetes. 3
Angiotensin receptor blockers (ARBs) are recommended for ACE inhibitor-intolerant patients with clinical or radiological signs of heart failure and LVEF <0.40. 3
Antiplatelet and Anticoagulation Therapy
Dual Antiplatelet Therapy (DAPT)
Aspirin:
- Administer aspirin at an initial oral loading dose of 150-300 mg (or 75-250 mg IV if oral not possible), followed by 75-100 mg daily for long-term treatment. 3
P2Y12 Inhibitors:
Add a P2Y12 receptor inhibitor to aspirin and maintain for 12 months unless contraindicated or excessive bleeding risk exists. 3, 4
For patients needing an antiplatelet effect within hours, initiate clopidogrel with a single 300 mg oral loading dose, then continue at 75 mg once daily. 4
Consider alternative P2Y12 inhibitors (ticagrelor or prasugrel) in patients identified as CYP2C19 poor metabolizers, as clopidogrel has reduced effectiveness in these patients. 4
Avoid concomitant use of clopidogrel with omeprazole or esomeprazole, as both significantly reduce the antiplatelet activity of clopidogrel. 4
Anticoagulation
Administer parenteral anticoagulation to all patients in addition to antiplatelet therapy. 3
For patients managed conservatively, continue unfractionated heparin (UFH) for at least 48 hours or until discharge, or alternatively administer enoxaparin or fondaparinux for the duration of hospitalization (up to 8 days). 3
Risk Stratification and Timing of Invasive Strategy
Risk Assessment Tools
Perform risk stratification using established risk scores such as GRACE or TIMI to guide management decisions. 2
Measure serial high-sensitivity cardiac troponin for both diagnosis and prognostic assessment. 2, 3
Obtain echocardiography to evaluate regional wall motion abnormalities, left ventricular ejection fraction, and hemodynamic status. 3, 5
Indications for Urgent/Early Angiography
Urgent angiography (<2 hours) is indicated for: 5
- Hemodynamic instability
- Ongoing ischemia despite intensive medical therapy
- Life-threatening arrhythmias
Early angiography (within 24 hours) is indicated for: 5
- Recurrent symptoms despite medical therapy
- 3-vessel CAD with elevated troponin
- Major arrhythmias in the setting of NSTEMI
Secondary Prevention and Lifestyle Modifications
Weight Management
Assess body mass index and waist circumference on each visit; target BMI of 18.5-24.9 kg/m² and waist circumference <40 inches for men and <35 inches for women. 1
If waist circumference is ≥35 inches in women or ≥40 inches in men, initiate lifestyle changes and consider treatment strategies for metabolic syndrome. 1
Physical Activity
Assess the patient's risk after NSTEMI based on in-hospital determination; a physical activity history or exercise test should guide initial prescription. 1
Encourage patients to achieve 30-60 minutes per day of moderate aerobic activity (such as brisk walking), preferably 7 days per week (but at least 5 days), supplemented by increased daily lifestyle activities. 1
Cardiac rehabilitation/secondary prevention programs are recommended, particularly for patients with multiple modifiable risk factors and moderate- to high-risk patients in whom supervised exercise training is warranted. 1
Exercise training can generally begin within 1-2 weeks after NSTEMI treated with PCI or CABG to relieve ischemia. 1
Smoking Cessation
Encourage complete smoking cessation at every visit; successfully treated patients may continue treatment for an additional 12 weeks to improve chances of long-term abstinence. 1
Family members living in the same household should also be encouraged to quit smoking to reinforce the patient's effort and decrease secondhand smoke risk. 1
Critical Pitfalls to Avoid
Never rely on a single troponin measurement to exclude NSTEMI, especially when the patient presents early after symptom onset. 2
Do not discontinue dual antiplatelet therapy prematurely, even if symptoms have resolved, as this increases risk of recurrent events. 3
Do not discharge patients too early based solely on symptom resolution; continuous monitoring is required for at least 24 hours. 3
Do not delay angiography in patients with recurrent symptoms and high-risk features such as 3-vessel CAD. 5
Do not continue rate-limiting medications (beta-blockers, non-dihydropyridine calcium channel blockers) at full doses if causing symptomatic bradycardia. 5
Do not administer nitrates if systolic blood pressure is <90 mmHg, severe bradycardia <50 bpm, or tachycardia >100 bpm without heart failure. 5