Table 2. Various Causes of Elevated Troponin and Mechanisms of MINOCA/TpNOCA.
| Etiologies | Mechanism of Troponin Release | Diagnostic Modality |
|---|---|---|
| Coronary causes (MINOCA) | ||
| Coronary plaque disruption | • Myonecrosis with plaque disruption (plaque rupture, ulceration, or erosion) is mediated by thrombosis, thromboembolism or vasospasm • Spontaneous thrombolysis is endogenous protective mechanism against thrombus formation |
• OCT/IVUS • CMR (confirms MI and edema) |
| Coronary embolism | • Myocardial hypoperfusion caused by corresponding coronary embolism | • OCT/IVUS • ICA • Sometimes CT |
| Coronary dissection | • Isolated dissection at coronary artery, leads to myocardial ischemia | • OCT/IVUS • ICA • CT |
| Coronary spasm | • Endothelial injury or ruptured vulnerable plaque cause myocardial injury | • OCT/IVUS • ICA with provocation test • Echocardiography (provocation test) • Sometimes CT |
| Myocardial causes | ||
| Myocarditis or inflammatory cardiomyopathy | • Inflammation causing myocardial injury (viral, bacterial or granulomatous inflammation) | • CMR • PET (particularly, cardiac sarcoidosis) |
| Takotsubo cardiomyopathy | • Myocardial stunning caused by increased stress hormones • Multivessel spasm • Plaque disruption |
• CMR • Sometimes CT |
| Hypertrophic cardiomyopathy | • Myocardial injury caused by interstitial fibrosis or hypoperfusion | • CMR • Sometimes CT |
| Dilated cardiomyopathy | • Myocardial injury resulting from left ventricle strain/overload | • CMR • Sometimes CT |
| Infiltrative cardiomyopathy | • Myocardial injury by amyloidosis, etc. | • CMR |
| Extra-cardiac causes | ||
| Pulmonary embolism | • Myocardial injury resulting from right ventricle strain/overload • Hypoxemia due to perfusion-ventilation mismatch • Hypoperfusion as consequence of low output and reduced coronary blood flow |
• CT • V/Q scan |
| Aortic dissection | • Extended flap from aortic dissection to coronary artery or decreased perfusion leads to myocardial ischemia | • CT |
| Stroke | • Decreased myocardial perfusion after stroke • Associated with increased prevalence of coronary artery diseases |
• Brain MRI • Myocardial SPECT • CMR |
| Sepsis | • Myocardial ischemia which caused by systemic hypoxemia from respiratory failure, hypotension or microcirculatory dysfunction | • Serum inflammatory marker • Myocardial SPECT • CMR |
SPECT = single photon emission CT, V/Q scan = ventilation-perfusion scan