Page 31 - Coronary hemodynamics in acute myocardial infarction - Matthijs Bax

Introduction
Early restoration of perfusion after myocardial infarction (MI) reduces
mortality, limits infarct size, and preserves left ventricular (LV) function.1-3 2 The primary objective of reperfusion therapy is not only to restore epicardial
vessel patency but also to reperfuse tissue in order to maintain myocyte
integrity and function and, thus, LV function. At present, it is unclear which
diagnostic method in the acute phase of MI accurately predicts the recovery
of LV function. Electrocardiographic (ECG) determinants such as ST-segment
deviation resolution4 and (in)direct measurements of microvascular function
after reperfusion therapy may indicate recovery of LV function).5,6 Angiographic
predictors include Thrombolysis In Myocardial Infarction (TIMI) flow grade,2,7,8
corrected TIMI frame count (cTfc),9 and myocardial blush grade as surrogates
for tissue reperfusion.10 Coronary flow velocity reserve (CFR) obtained by digital subtraction cine-angiography significantly correlated with regional myocardial
function at follow-up in the setting of acute MI.5 Both Doppler derived CFR and
blood flow velocity pattern may indicate LV function recovery.11-13 The purpose
of this study was to identify early determinants (at the time of reperfusion)
of recovery of LV function by a direct comparison of the aforementioned parameters in patients with acute MI treated with primary percutaneous
coronary intervention (PCI).
Methods
Patient selection
We studied 100 consecutive patients presenting with a first, acute, anterior MI treated with primary PCI. Acute MI was defined as chest pain lasting more than 30 min in conjunction with persistent ST-segment elevation in the precordial leads. Exclusion criteria were cardiogenic shock defined as systolic blood pressure below 90 mm Hg despite conservative measurements, previous anterior MI, previous coronary artery bypass grafting, prior LV ejection fraction <40%, LV hypertrophy (interventricular septum or posterior wall >12 mm), absence of thoracic windows for echocardiography, three-vessel coronary artery disease, TIMI grade 2 or 3 flow at time of initial angiography, or unsuccessful PCI defined as no antegrade flow and/or >50% residual stenosis in the infarct-related artery
Prediction of recovery of LV function
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