Author + information
- Mustafa Tarık Ağaç1,
- Suret Ağaç4,
- Levent Korkmaz1,
- Turhan Turan2,
- Hüseyin Bektaş1,
- Ali Rıza Akyüz2,
- Mustafa Çetin1,
- Hakan Erkan1,
- Bülent Vatan3 and
- Şükrü Çelik1
The major determinant of final infarct size for a given coronary occlusion is the size of myocardium that the artery perfuses. Defining the initial area-at-risk (AAR) for infarction has major clinical implications since it permits an accurate estimate of myocardial salvage provided by reperfusion therapies. We proposed a new index 'Relative Importance Index (RII)' to predict potential infarct size in patients with anterior MI.
The aim of the study is to assess the predictive role of RII for reduction in systolic function and its relation to adverse clinical outcomes.
One Hundred twenty-three acute anterior MI patients with their first acute coronary syndrome incident were consecutively and prospectively enrolled to the study. Patients with a clinical history of congestive heart failure, valvular heart disease, and previous coronary revascularization were excluded. All patients underwent primary percutaneous coronary intervention (PCI) for revascularization. Angiographic exclusion criteria were 1) pre-procedural TIMI flow ≥2 in the infarct related artery, 2) chronic total occlusion of other arterial territory 3) any visible collateral flow to infarct related artery 4) diffuse disease at proximal segments of coronary arteries that precludes defining reference segment. Coronary diameters were measured with quantitative coronary analysis program. RII was calculated by dividing culprit segment diameter to the sum of diameters of LAD, Cx, and RCA at their proximal segments (Figure 1). Troponin I (TnI) concentration at 72 hour was chosen as a serological estimate of infarct size. We evaluated 1-month follow up rates of major clinical endpoints (MCE), which is defined as death, non fatal MI, stroke, and new congestive heart failure. Left ventricular EF (LVEF) at 1st month was chosen as an index for systolic function.
RII was significantly and negatively correlation LVEF (r=-0.65, p<0.001) (Figure 2). As RII of culprit lesion increased there was tendency to end up with lower EF. Likewise, RII was significantly correlated with 72 h TnI (r=0.48, p<0.001). Patients were dichotomized according to median value of RII (median RII=0.30) (Table 1). Supra-median RII was associated with lower EF and higher incidence of composite MACE. The mortality (12.9% vs. 6.6%), non-fatal MI (6.5% vs. 3.3%), and new CHF (12.9% vs. 3.3%) rate in supra-median RII group trend higher but they did not reach statistical significance. An RII >0.30 had a 88% sensitivity and 60% specificity (ROC area 0.82, p<0.001, CI [0.73-0.90]) for predicting severe LV dysfunction (LVEF <30%) (Figure 3).
A Simple index derived from coronary angiography at time of primary PCI can predict LV systolic function loss and adverse clinical outcome in patients with acute anterior myocardial infarction.
|RII < 0.30|
|LVEF, %||42.8 ± 9.4||32.8 ± 8.6||<0.001|
|Age, years||62 ± 14||63 ± 15||NS|
|Diabetes mellitus, n||9||11||NS|
|72 h TnI, ng/ml||24 ± 16||42 ± 24||<0.001|
|Final TIMI flow 2-3,||55||57||NS|
|Door-to-balloon time, min||48 ± 10||50 ± 9||NS|
|Symptom-to-balloon time, hr*||4(3-6)||3.5(3-6)||NS|
|Death, n (%)||4 (6.6)||8 (12.9)||NS|
|Stroke, n (%)||0 (0)||1 (1.6)||NS|
|Non fatal MI, n (%)||2 (3.3)||4 (6.5)||NS|
|New CHF, n (%)||2 (3.3)||8 (12.9)||NS|
|Composite MCE, n (%)||8 (13.1)||21 (33.9)||0.01|
CHF, congestive heart failure; LVEF, left ventricle ejection fraction; MCE, major clinical events; RII, relative importance index; TnI, troponin I; TIMI, Thrombolysis in Myocardial Infarction; NS, non-significant Data are expressed as no. (%) or mean ± standard deviation. *Data are presented as median and interquartile ranges.