Final Myocardial Blush Grade Predicts Troponin I Elevation in Unstable Angina Patients Undergoing Percutaneous Intervention

Background

Improved myocardial blush grade is associated with better MACE outcomes in acute myocardial infarction patients but there are no data on myocardial blush grade (MBG) assessment in unstable angina (UA) patients treated with coronary intervention. We sought to evaluate the use of angiographic MBG assessment in a cohort of UA patients treated with angioplasty.

Methods

Three hundred and seventy-two consecutive UA patients (mean age 68±1 years) treated with PCI were included. No patients had a pre-procedural troponin I (TnI) elevation. Final MBG was recorded for the territory subserving the PCI treated culprit lesion in each patient and graded 0 (no blush), 1 (minimal blush), 2 (moderate blush) and 3 (normal blush). TnI (normal range <0.1μg/L) was measured 24h post-procedure. Patients who did not have a TnI elevation (i.e. <0.1μg/L) were ascribed a value of 0.1μg/L. Patients were followed up (mean 962±83 days) by postal questionnaire.

Results

Baseline risk factors were comparable between final MBG groups. There was no significant difference in mortality rate between groups. Post-procedural troponin I elevations were 0.34±0.12, 0.68±0.26, 0.14±0.01 and 0.11±0.01 for MBG groups 0, 1, 2 and 3 (p<0.001). Patients with minimal MBG underwent proportionately more target vessel revascularisation (p<0.05).

Conclusions

Improved blush grade in UA patients undergoing PCI is associated with lower post-procedural TnI elevation. Identification of UA patients with poor final MBG may allow a window of opportunity for the administration of adjuvant therapies to improve microvascular perfusion in the future.

Keywords: Myocardial blush, Unstable angina, Troponin I