Risk stratification in patients with inferior acute myocardial infarction treated by percutaneous coronary interventions: the role of admission troponin T.

BACKGROUND: Cardiac troponin T (cTnT) elevations on admission indicate a high-risk subgroup of patients with ST-segment elevation acute myocardial infarction (AMI). This finding has been attributed to less effective reperfusion after thrombolytic therapy. The aim of this study was to determine the role of admission cTnT on the efficacy of percutaneous coronary interventions (PCIs) in inferior AMI. METHODS AND
RESULTS: One hundred fifty-nine consecutive patients with inferior ST-segment AMI were enrolled and followed up for a mean of 448 days. Patients were stratified by cTnT on admission. A cTnT >/=0.1 microg/L was found in 58% of patients. These patients had longer time intervals from onset of symptoms to therapy (P:<0. 001) and higher 30-day (10.8% versus 1.5%, P:=0.027) and long-term (17.2% versus 4.5%, P:=0.023) cardiac mortalities. Rates of the combined end point of death, nonfatal reinfarction, and need for repeated target vessel revascularization procedures were not different in cTnT groups (log rank, 0.69; P:=0.41). PCI was attempted in 93.3% of cTnT-positive and 98.5% cTnT-negative patients (P:=0.24) but was less frequently successful in patients with cTnT >/=0.1 microg/L (77.9% versus 96.9%, P:<0.001). Coronary stenting reduced 30-day and long-term cardiac mortality, particularly among cTnT-positive patients. In a multivariate analysis, cTnT indicated an approximately 5-fold-higher risk (adjusted OR, 4.6; 95% CI, 0.79 to 27.11; P:=0.089) and was a strong albeit not independent risk predictor.
CONCLUSIONS: In inferior AMI, a positive admission cTnT is associated with lower success rates of direct PCI and higher rates of cardiac events over the short and long term. These patients benefit from coronary stenting.