Elevations in troponin I after percutaneous coronary interventions are associated with abnormal tissue-level perfusion in high-risk patients with non-ST-segment-elevation acute coronary syndromes

Background - In the setting of non-ST-segment - elevation (NSTE) acute coronary syndromes (ACS), the pathophysiological mechanisms underlying post - percutaneous coronary intervention (PCI) cardiac troponin I (cTnI) elevation remain unclear. Methods and Results - We evaluated the relationship between troponin elevation and tissue-level perfusion using the TIMI flow grade, corrected TIMI frame count, TIMI myocardial perfusion grade ( TMPG), and myocardial contrast enhancement by intracoronary myocardial contrast echocardiography (MCE) before and immediately after PCI performed within 24 to 48 hours of hospital admission in 42 high-risk ( angina at rest, unequivocal ST-segment depression, and cTnI elevation) patients with NSTE-ACS. All patients were treated with glycoprotein IIb/IIIa inhibitors ( 27 with tirofiban and 15 with abciximab) and had successful PCI. Fourteen patients had a postprocedural cTnI elevation, whereas 28 did not. TMPG 0/1 after PCI was observed more frequently in patients with postprocedural cTnI elevation ( 43% versus 7%; P < 0.02). cTnI levels were higher among patients with TMPG 0/1 versus patients with TMPG 2/3 ( 5.3 +/- 2.7 versus 1.5 +/- 1.3 ng/mL; P < 0.0001). Patients with postprocedural cTnI elevation also presented a significantly lower number of perfused segments at MCE (59% versus 81%; P = 0.02) as well as a lower MCE score index (0.65 +/- 0.38 versus 0.89 +/- 0.21; P < 0.02). Conclusions - Postprocedural cTnI elevation in high-risk patients with NSTE-ACS is associated with an abnormal tissue-level perfusion.