Background: Abnormal levels of serum cardiac troponin I (cTnI) are occasionally found in patients presenting with acute coronary syndromes but having insignificant coronary artery disease. Before one concludes that an abnormal cTnI level is a false-positive result, the possibility of coronary vasospasm should be considered. This study investigated whether coronary vasospasm could be a reason for elevated cTnI in this patient population.
Methods and results: This investigation enrolled 93 patients who presented to the emergency department with suspected coronary ischemia and had insignificant coronary artery disease. cTnI was elevated in 23 patients (25%) and was normal in 70 patients (75%). Coronary vasospasm, documented by an ergonovine provocation test, was found in 38 patients (41%). Patients with elevated cTnI levels, compared with those with normal cTnI, were older (63 +/- 13 y vs 56 +/- 14 y, P =.032), had a higher incidence of males (78% vs 52%, P =.049) and positive ergonovine provocation tests (74% vs 30%, P <.0001), and tended to have a lower incidence of hypercholesterolemia (26% vs 48%, P =.088) and normal electrocardiograms (48% vs 70%, P =.078). Multivariate analysis showed that the variables independently associated with an elevated cTnI level included coronary vasospasm (odds ratio 2.41, 95% CI 1.48-3.18, P <.0001) and hypercholesterolemia (odds ratio 0.64, 95% CI 0.47-0.99, P =.049). Coronary vasospasm (positive ergonovine provocation test) could explain 74% of elevated cTnI levels in patients with insignificant coronary stenosis.
Conclusions: In patients with acute coronary syndrome with elevated cTnI and insignificant coronary artery disease, the possibility of coronary vasospasm as a cause of elevated cTnI should be considered.