Coronary vasospasm as a possible cause of elevated cardiac troponin I in patients with acute coronary syndrome and insignificant coronary artery disease.

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.