Critical Alerts

• Troponin rise is mandatory: NSTEMI = ACS + positive troponin
• No emergent cath for NSTEMI: Unlike STEMI; invasive strategy within 24-72h
• GRACE score guides timing: Higher risk = earlier cath
• Still life-threatening: Higher in-hospital mortality than some realize
• DAPT is standard: Aspirin + P2Y12 inhibitor
• Anticoagulation required: Heparin or enoxaparin

Key Diagnostics

Emergency Treatments

Overview

Non-ST-Elevation Myocardial Infarction (NSTEMI) is a type of acute coronary syndrome (ACS) characterized by myocardial injury (elevated cardiac troponin with rise and/or fall pattern) in the context of acute ischemia, without persistent ST-segment elevation on ECG. It is distinguished from unstable angina by the presence of positive troponin.

Classification

Spectrum of ACS:

Universal Definition of MI Types:

Most NSTEMI = Type 1: Due to acute coronary artery plaque disruption

Epidemiology

• Prevalence: 2-3× more common than STEMI
• Mortality: In-hospital 3-5%; 30-day 5-8%; 6-month 12-15%
• Long-term outcomes: Higher rates of recurrent events than STEMI if untreated
• Age: Older than STEMI patients on average
• Gender: More common presentation of ACS in women

Etiology

Primary (Type 1 MI):

• Atherosclerotic plaque rupture or erosion
• Non-occlusive thrombus formation
• Distal embolization
• Coronary artery dissection

Secondary (Type 2 MI - Supply/Demand Mismatch):

High-Risk Features

HEART Score for Risk Stratification

Mimics of NSTEMI

Type 2 MI vs Type 1 MI

• Type 2: Clear secondary precipitant (sepsis, anemia, tachycardia)
• Treatment differs: Address precipitant vs revascularization
• Prognosis differs: Based on underlying condition

ECG

Obtain Within 10 Minutes:

Serial ECGs: Repeat with ongoing symptoms; ischemia may be dynamic

Cardiac Biomarkers

High-Sensitivity Troponin (hs-cTn):

Rapid Rule-Out Protocols:

• 0/1-hour or 0/3-hour hs-cTn algorithms
• Rule out: Very low baseline and delta
• Rule in: Very high or significant delta
• Observe: Intermediate values

Laboratory Studies

Imaging

Echocardiography:

• Assess LV function
• Wall motion abnormalities
• Valvular complications (MR)
• Pericardial effusion

Coronary Angiography (Gold Standard for Anatomy):

• Determines revascularization strategy
• Timing based on risk stratification

Admission Criteria

• All confirmed NSTEMI patients require admission
• Coronary care or monitored unit

ICU Criteria

• Hemodynamic instability
• Cardiogenic shock
• Severe arrhythmias
• Heart failure requiring IV therapy
• Mechanical complications

Observation/Rule-Out

• Patients with chest pain and low-intermediate risk
• Serial troponins and observation
• Stress testing or CT coronary angiography for intermediate risk

Discharge Planning

• DAPT education
• Cardiac rehabilitation referral
• Risk factor modification
• Follow-up with cardiology (1-2 weeks)

Condition Explanation

• "You are having a heart attack, but the type that does not fully block your artery."
• "We need to give you blood thinners and watch you closely to prevent further damage."
• "You will likely need a procedure to look at your heart arteries."

Medication Adherence

• Do not stop aspirin or P2Y12 inhibitor without consulting cardiologist
• DAPT usually for 12 months post-stent
• Statin should be lifelong

Lifestyle Modification

• Smoking cessation (most important modifiable risk factor)
• Heart-healthy diet
• Regular exercise (cardiac rehab)
• Weight management
• Blood pressure and diabetes control

Warning Signs Post-Discharge

• Return of chest pain
• Shortness of breath
• Palpitations
• Lightheadedness or syncope
• Bleeding (especially GI)

Elderly

• Higher risk, more atypical presentations
• Bleeding risk with aggressive antithrombotics
• Individualized approach to invasive strategy

Women

• More atypical presentations
• Underdiagnosed and undertreated historically
• Spontaneous coronary artery dissection (SCAD) more common

Diabetes

• Higher risk of adverse outcomes
• More likely to benefit from early invasive strategy
• CABG may be preferred over PCI for multivessel disease

Chronic Kidney Disease

• High cardiovascular risk
• Adjust anticoagulant and antiplatelet dosing
• Contrast nephropathy concern with cath
• Higher bleeding risk

Prior CABG

• Native vessel vs graft disease
• Complex interventions
• May need repeat surgery or PCI of grafts

Performance Indicators

Documentation Requirements

• Symptom onset time
• ECG findings and timing
• Troponin values and trend
• Risk stratification score (GRACE, HEART)
• Antiplatelet and anticoagulation given
• Cardiology consultation
• Invasive strategy plan

Diagnostic Pearls

• Serial troponins are essential: Single negative doesn't rule out
• Normal ECG does not exclude NSTEMI: 50% have non-diagnostic ECG
• Wellens' pattern: Biphasic or deeply inverted T-waves in V2-V3 = proximal LAD stenosis
• aVR ST elevation + diffuse depression: Left main or severe 3-vessel disease
• Type 2 MI exists: Not all troponin elevation is Type 1 MI
• HEART score for chest pain risk: Validated decision aid

Treatment Pearls

• Aspirin is forever: Unless true allergy
• Ticagrelor preferred over clopidogrel: But higher bleeding
• Prasugrel only post-PCI: Contraindicated with prior stroke
• Don't delay anticoagulation: Start immediately
• Early cath for high-risk features: Within 24 hours
• High-intensity statin for all: Unless contraindicated

Disposition Pearls

• All NSTEMI need admission: No outpatient management
• DAPT for 12 months post-stent: Minimum 1 month for high bleed risk
• Cardiac rehab improves outcomes: Refer all patients
• Follow-up is critical: 50% don't complete cardiac rehab