Page 42 - Coronary hemodynamics in acute myocardial infarction - Matthijs Bax

Chapter 2
APV. In previous studies, ST-segment resolution was slower in patients with anterior MI than with non-anterior MI. This may explain the absence of association between ST resolution and CFR in our study in patients with only anterior MI.
Angiographic parameters in relation to LV function recovery
Our current knowledge on factors influencing LV function recovery after acute MI is based on angiographic studies. In large, multicenter studies evaluating thrombolysis, TIMI flow grading appeared to be of clinical use for risk stratification.2,8,21 In our study, TIMI flow after PCI showed a weak correlation with LV function recovery at one week (r = 0.30, p = 0.015), and myocardial blush grade was weakly correlated with regional function recovery at one day (r = 0.27, p = 0.02). Our study consisted of non-high-risk patients (excluding shock, low ejection fraction, previous anterior MI, and excluding cardiac events on follow-up). This may be the reason for a diminished ability to detect a relationship between angiographic parameters and LV function recovery, whereas CFR is a potent predictor of LV function recovery in these patients.
Doppler-flow parameters in relation to LV function recovery
In our study, CFR was the only independent predictor of long-term global and regional LV function recovery. Coronary flow velocity reserve after PCI predicted not only the change in LV function over six months but also the ventriculographic ejection fraction at five weeks that is associated with long- term mortality. Coronary flow velocity reserve as a predictor being superior to the other parameters of myocardial perfusion may be explained by the direct way of interrogating the microvascular bed, thereby more accurately reflecting microvascular integrity and function. Iwakura et al. demonstrated altered coronary flow velocity patterns as the appearance of systolic retrograde flow, diminished systolic antegrade flow, and rapid deceleration of diastolic flow in patients with the no-reflow phenomenon after reperfusion therapy.16 These flow velocity patterns appeared to be inversely related with in-hospital22 and with one-month recovery of LV function.11 This is in accordance with our findings that absence of early systolic retrograde flow immediately after primary PCI was associated with recovery of global and regional LV function at one-day follow- up and with regional LV function improvement at one week. At five weeks, systolic retrograde flow, next to CFR, independently correlated with ejection fraction. However, long-term LV function changes were not predicted by altered
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