Elevated troponin in the absence of myocardial infarction

ELEVATED TROPONIN IN THE ABSENCE OF MYOCARDIAL INFARCTION

LIONEL J. MALEBRANCHE, MD, RPVI, FACC INVASIVE CARDIOLOGIST UPH REGIONAL PHYSICIAN COUNCIL PHYSICIAN GOVERNANCE COUNCIL

ALEXA MILLER, MD FAMILY MEDICINE RESIDENT UIC

I HAVE NO RELEVANT FINANCIAL DISCLOSURES

? Objectives ? Definition ? Cellular mechanisms ? Demand ischemia ? Troponin elevation in ischemic heart disease ? Non MI related troponin elevation ? Case review

Definition

? Cardiac troponin is the standard test to confirm acute MI ? Troponin complex has 3 sub units: Troponin T, I and C ? Cardiac troponin are regulatory proteins that control calcium mediated

interaction of actin and myosin ? Assay in use specific for the myocardium ? Not specific for acute thrombotic occlusion of coronary artery ? Increased troponin seen in sepsis, fib, HF, PE, myocarditis,

myocardial contusion, renal failure, etc. ? False positive due to skeletal muscle injury is rare

PATHOPHYSIOLOGY

? prolonged ischemia-->myocardial necrosis-->gradual release of myofibril-bound cytosolic complexes--> cardiac troponin release

? increased myocyte permeability ? myocardial depressive factors seen in sepsis and other inflammatory states--> degradation of free troponin to lower weight fragments. ? Troponin may be elevated without myocyte cell death ? Myocardial depression during sepsis is fully reversible

4TH UNIVERSAL DEFINITION OF M I1. The criteria for type 1 MI includes detection of a rise and/or fall of cTn with at least one value above the 99th

percentile and with at least one of the following: a. Symptoms of acute myocardial ischemia; b. New ischemic electrocardiographic (ECG) changes; c. Development of pathological Q waves; d. Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality in a pattern consistent with an ischemic etiology; e. Identification of a coronary thrombus by angiography including intracoronary imaging or by autopsy.

2. The criteria for type 2 MI includes detection of a rise and/or fall of cTn with at least one value above the 99th percentile and evidence of an imbalance between myocardial oxygen supply and demand unrelated to coronary thrombosis, requiring at least one of the following: a. Symptoms of acute myocardial ischemia; b. New ischemic ECG changes; c. Development of pathological Q waves; d. Imaging evidence of new loss of viable myocardium, or new regional wall motion abnormality in a pattern consistent with an ischemic etiology.

4TH UNIVERSAL DEFINITION OF MI

3. Cardiac procedural myocardial injury is arbitrarily defined by increases of cTn values (>99th percentile URL) in patients with normal baseline values (99th percentile URL) or a rise of cTn values >20% of the baseline value when it is above the 99th percentile, but it is stable or falling.

4. Coronary intervention-related MI is arbitrarily defined by elevation of cTn values >5 times the 99th percentile URL in patients with normal baseline values. In patients with elevated pre-procedure cTn in whom the cTn levels are stable (20% variation) or falling, the post-procedure cTn must rise by >20%. However, the absolute postprocedural value must still be at least five times the 99th percentile URL. In addition, one of the following elements is required: a. New ischemic ECG changes; b. Development of new pathological Q waves; c. Angiographic findings consistent with a procedural flow-limiting complication such as coronary dissection, occlusion of a major epicardial artery or a side branch occlusion/thrombus, disruption of collateral flow or distal embolization.

PATHOPHYSIOLOGY

? Demand ischemia ? Mismatch between myocardial oxygen demand and supply ? evidence of ischemia w/o CAD ? 2018 Universal definition of MI (ESC/ACC/AHA) refers to type 2 MI when increased oxygen demand or decreased supply in absence of primary thrombotic process. ? May be seen in sepsis, septic shock, SIRS, Hypotension, hypovolemia, atrial fibrillation and other tachyarrhythmias

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