Cardiac α V β 3 integrin expression following acute myocardial infarction in humans.

Objective: Maladaptive repair contributes towards the development of heart failure following myocardial infarction (MI). The α _v β ₃ integrin receptor is a key mediator and determinant of cardiac repair. We aimed to establish whether α _v β ₃ integrin expression determines myocardial recovery following MI.
Methods: ¹⁸ F-Fluciclatide (a novel α _v β ₃ -selective radiotracer) positron emission tomography (PET) and CT imaging and gadolinium-enhanced MRI (CMR) were performed in 21 patients 2 weeks after ST-segment elevation MI (anterior, n=16; lateral, n=4; inferior, n=1). CMR was repeated 9 months after MI. 7 stable patients with chronic total occlusion (CTO) of a major coronary vessel and nine healthy volunteers underwent a single PET/CT and CMR.
Results: ¹⁸ F-Fluciclatide uptake was increased at sites of acute infarction compared with remote myocardium (tissue-to-background ratio (TBR _mean ) 1.34±0.22 vs 0.85±0.17; p<0.001) and myocardium of healthy volunteers (TBR _mean 1.34±0.22 vs 0.70±0.03; p<0.001). There was no ¹⁸ F-fluciclatide uptake at sites of established prior infarction in patients with CTO, with activity similar to the myocardium of healthy volunteers (TBR _mean 0.71±0.06 vs 0.70±0.03, p=0.83). ¹⁸ F-Fluciclatide uptake occurred at sites of regional wall hypokinesia (wall motion index≥1 vs 0; TBR _mean 0.93±0.31 vs 0.80±0.26 respectively, p<0.001) and subendocardial infarction. Importantly, although there was no correlation with infarct size (r=0.03, p=0.90) or inflammation (C reactive protein, r=-0.20, p=0.38), ¹⁸ F-fluciclatide uptake was increased in segments displaying functional recovery (TBR _mean 0.95±0.33 vs 0.81±0.27, p=0.002) and associated with increase in probability of regional recovery.
Conclusion: ¹⁸ F-Fluciclatide uptake is increased at sites of recent MI acting as a biomarker of cardiac repair and predicting regions of recovery.
Trial Registration Number: NCT01813045; Post-results.
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