Background: The incidence and correlates of postinterventional cardiac troponin T (cTnT) elevation have not been evaluated in patients with successful directional atherectomy (DCA).
Methods: Total creatine kinase (CK) activity, CK-MB mass concentrations and cTnT levels were measured in 36 patients before, and serially 4, 24, 48 and 72 hours after successful DCA. Patients were followed for death, Q-wave infarction, need for emergency bypass surgery, periprocedural vascular complications (transient in-lab vessel closure, side branch compromise, large dissection), and non-Q-wave infarction on ECG. Patients were followed for clinical outcomes and angiographic restenosis for 6 months. Vascular correlates were studied by coronary angiography and intravascular ultrasound before, immediately after and 4 hours after elective and successful DCA.
Results: 25 patients (69.4%) had elevated levels of cTnT, whereas CK-MB mass > or = 6 ng/ml and mild elevations of total CK activity were present in only 36.1 and 5.6%, respectively. Elevated cTnT was related to vascular complications in 44% of cases. Inapparent microembolization of platelets or plaque debris was considered responsible for most of the remaining micronecroses. During 6 month follow-up rates of clinical restenosis (44 vs 9%, p = 0.059) tended to be higher in patients with as compared to patients without cTnT release after DCA.
Conclusion: Successful DCA is associated with postprocedural elevations of cTnT which relate to minor vascular complications and presumably microembolization of platelets or plaque debris. The superior diagnostic performance of cTnT compared to CK-MB mass may relate to more sensitive identification of microinfarction. Further studies are mandatory to confirm the association between elevation of cTnT and risk of restenosis and TVR.