TCT-635 ACUTE AND MID-TERM CLINICAL OUTCOMES OF THE EVEROLIMUS-ELUTING BIORESORBABLE VASCULAR SCAFFOLDS IN AN ALL-COMER COHORT

(NIR) dye, Cy5.5-SE covalently binds to the extracellular proteins through their NH2 groups. Proteolysis and tissue degradation should result in dye washout and loss of its absorption, which may provide a measure of these processes. METHODS: In domestic pigs (w30 kg, n 1⁄4 14) following intercostal incision, prospective at risk and remote areas were labeled with Cy5.5-SE by 1-min touch of the epicardium with a 6-mm sponge soaked in 0.2 mM dye solution in 0.1 M NaPi buffer (pH 8.5). Ten min after staining, the 1st and 2nd diagonal branches of the left anterior descending coronary artery (LAD) were ligated. Immediately after epicardial staining and shortly after ligation, point spectra (400-1200 nm) were acquired using light guide attached to a spectrometer, which was followed by chest closure. Seven, 14 and 21 days later, the same procedure of spectra acquisition were repeated after the chest was opened again. Peaks of Cy5.5 (680 nm) as well as oxyand deoxy-(hemoglobin(Hb)+myoglobin(Mb)) (560-580 nm) were analyzed. Post-mortem analysis was achieved via both macroscopical staining of shortaxis heart slices with triphenyltetrazolium chloride (TTC) and microscopical H&E and trichrome collagen staining of fixed myocardial specimen. RESULTS: Ligation of the LAD branches resulted in immediate deoxygenation of the area at risk while subepicardial labeling of Cy5.5 did not affect this process. Infarction progression, as evidenced by TTC-negative area on short-axis slice, resulted in faster signal decay of Cy5.5 within the infracted subepicardium than that in the remote area (Table 1). After 7 days, signal of total-(Hb+Mb) decreased by 42% in the infarct relative to the remote area (0.23 0.11 vs. 0.40 0.08, p<0.05), which correlated with change of Cy5.5. Post-mortem microscopic examination revealed gradual cardiomyocyte and vasculature degradation and collagen accumulation, which was comparable with signal change of Cy5.5 and total-(Hb+Mb). CONCLUSION: The observations are consistent with activation of tissue degradation within the infracted myocardium due to inflammation and proteolysis. The method has potential for in vivo evaluating the efficacy of regenerative interventions on infracted myocardium with great accuracy.