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

https://doi.org/10.1016/j.hlc.2006.05.008Get rights and content

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 <0.1 μg/L) was measured 24 h post-procedure. Patients who did not have a TnI elevation (i.e. <0.1 μg/L) were ascribed a value of 0.1 μg/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.

Introduction

The timely restoration of coronary blood flow in patients with acute coronary syndromes is a primary objective for interventional cardiologists.1 The definition of procedural success has traditionally related, in part, to the restoration of TIMI 3 flow in the culprit vessel.2, 3 However, rather than TIMI flow, it is increasingly recognized that microvascular perfusion, downstream of the epicardial vessel, may be of more importance with regard to myocardial salvage and long term outcome.4 Myocardial blush grade (MBG) is a simple, easily performed angiography based technique for evaluating microvascular cardiac perfusion.5 It has been extensively studied in the setting of acute myocardial infarction treated with thrombolytic therapy6 and primary angioplasty.7 Patients showing improved final myocardial blush grade have reduced infarct size as judged by cardiac enzyme release,7 lower ejection fraction5, 8 and reduced mortality.5, 9

Though there are limited data for patients presenting with non-ST elevation myocardial infarction,10 there are currently no blush data for patients presenting with unstable angina without initial troponin I elevation. We therefore studied a cohort of unstable angina patients presenting at our institution who underwent early coronary angioplasty and stenting to evaluate the impact of final myocardial blush grade on clinical outcome.

Section snippets

Study Population

From January 1999 to April 2001, 372 consecutive patients (266 males) presenting to our institution with unstable angina, underwent coronary intervention to the culprit lesion. Unstable angina was defined as typical retrosternal chest discomfort occurring for at least 15 min in the absence of admission troponin I elevation with or without electrocardiographic changes of ischaemia. No patients had a pre-procedural troponin I elevation to differentiate these patients from non-ST elevation

Baseline Demographic Data

There was no difference in baseline characteristics with respect to final myocardial blush grades (Table 1). The prevalence of coronary risk factors and previous history of coronary revascularisation were similar between blush grades. There was no difference in mean age between groups.

Angiographic Data

The left anterior descending artery was most frequently intervened upon (168/372) and comparatively few saphenous vein graft interventions were performed (27/372) (Table 2). Angiographic success was achieved in

Discussion

Assessment of myocardial blush grade in acute coronary syndrome patients presenting with acute myocardial infarction is a simple angiographic technique for predicting outcomes.5 There are considerable data that tissue myocardial perfusion predicts outcomes in presenting with ST elevation myocardial infarction.5, 6, 7 More recently, myocardial blush assessment has been expanded to patients presenting with non-ST elevation MI in whom post-procedural troponin elevation was associated with impaired

Acknowledgment

The authors wish to acknowledge the work of Marisa Madigan who assisted in the collection of follow up data for patients in the study.

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