P1823 Feasibility of CCTA in assessment of luminal changes and coronary shear stress evolution after implantation of bioresorbable vascular scaffolds

Abstract Funding Acknowledgements PlaqueImage - financed by the National Authority of Scientific Research and Innovation and the Romanian Ministry of European Funding Background Coronary shear stress (CSS) is a well-established local mechanical factor in atherogenesis, progression and destabilization of atherosclerotic plaques. Analysis of CSS after coronary stent placement is still lacking of large clinical studies. Purpose: The aim of this study was to: (1) test the feasibility of Coronary Computed Tomography Angiography (CCTA) for assessment of local hemodynamic and luminal changes after implantation of bioresorbable vascular scaffolds (BVS), and (2) to investigate CSS modifications after BVS implantation. Methods: We conducted a single center, prospective pilot study on 73 patients with coronary artery disease who underwent elective percutaneous coronary intervention (PCI); group 1 (n = 30) – patients with BVS and group 2 (n = 43) – patients with bare metal stent (BMS) implanted. CCTA scanning was performed in all patients prior PCI and at 12 months after PCI. The mean CSS at proximal and at distal part of the stented segment and at the level of the minimal lumen area (MLA) was calculated at baseline and at 12 months after BVS placement. Results: CCTA revealed a higher incidence of severe coronary stenosis in group 1 (73%) than in group 2 (30%) (p &amp;lt; 0.0001). Sensibility of visual evaluation for identification of in-stent restenosis on CCTA was increased in BVS group (94%) than in BMS group (76.19%) (p = 0.0006), hence the group 1 had lower incidence of non-diagnostic evaluations. Mean CSS at the stented site was significantly lower at 12 months (1.9 +/- 0.68 Pa) that average CSS at baseline (2.87 +/- 3.08 Pa) (p = 0.0001). CSS analysis showed also a significantly decreased values at proximal level from 3.39 +/- 1.93 Pa at baseline to 1.91 +/- 0.68 Pa at follow up (p &amp;lt; 0.0001), but not a significant decrease at distal part – 1.3+/-0.72 Pa at baseline and 1.59 +/- 0.65 Pa at 12 months follow up (p = 0.9). Conclusions: CCTA is a feasible technique for assessment of luminal changes following BVS implantation. BVS implantation contribute to the improvement of local hemodynamics by restoring physiological pattern of coronary flow, as demonstrated by the computational fluid hemodynamics assessment of coronary circulation. </jats:sec

P360 Site specific phenotype of atherosclerotic lesions according to plaque location within the coronary tree, a CCTA based study

Abstract Funding Acknowledgements Research grant PlaqueImage, contract number 26/01.09.2016, SMIS code 103544, Project funded by the European Union and the Government of Romania Background The coronary CT angiography (CCTA)-based differences in composition, morphology and vulnerability of coronary plaques (CPs), according to their location within the coronary tree, have not been investigated so far. Purpose We sought to perform a comparative analysis between plaques located at different levels within the coronary tree, to identify the differences in plaque composition, morphology, and vulnerability between the three major coronary branches. Methods We conducted a cross-sectional, observational study on 75 patients with stable coronary artery disease who underwent CCTA for assessment of coronary lesions that exhibited at least one vulnerable plaque (VP) in the coronary tree. After image acquisition, coronary plaque analysis was performed with the use of the Syngo.via Frontier (Siemens) software. Plaque analysis also included evaluation of presence of VM: low attenuation plaque – LAP; napkin ring sign – NRS; spotty calcifications – SC; positive remodeling – PR. VP were defined as lesions that presented at least 1 vulnerability marker (VM). In total, 90 coronary VPs located at the level of the left anterior descending (LAD; n = 30), circumflex (CXA; n = 30) and right coronary artery respectively (RCA; n = 30) were identified and analyzed. Results Lesions located in the RCA presented a significantly higher length (LAD - 18.67± 5.49 vs. CXA - 15.48 ±3.73 vs. RCA - 20.47 ± 5.97 mm, p = 0.001), a higher degree of stenosis (LAD - 57.77 ± 8.62 vs. CXA - 54.50 ± 11.25 vs. RCA - 59.63 ± 10.42 mm, p = 0.022), and were more voluminous (LAD - 187.9 ± 86.03 vs. CXA - 146.9 ± 102.4 vs. RCA - 248.1 ± 11.4 mm3, p = 0.0007) compared to those located in the LAD and CXA, but no difference was observed regarding the remodeling (p = 0.180) or eccentricity indexes (p = 0.423). Plaque composition was also significantly different according to plaque location: calcified volume (LAD - 44.07 ± 63.90 vs. CXA - 12.40 ± 19.65 vs. RCA - 33.69 ± 34.38 mm3, p = 0.002), non-calcified volume (LAD - 143.8 ± 76.02 vs. CXA - 134.5 ± 102.2 vs. RCA - 214.4 ± 99.67 mm3, p = 0.002), lipid rich volume (LAD - 14.95 ± 22.69 vs. CXA - 6.44 ± 13.42 vs. RCA -16.07 ± 15.74 mm3, p = 0.0005), fibrotic volume (LAD - 128.9 ± 66.10 vs. CXA - 128.1 ± 91.56 vs. RCA - 198.3 ± 92.34 mm3, p = 0.003). The highest number of VM per plaque was present in the LAD (LAD - 2.2 ± 0.8 vs. CXA - 1.6 ± 0.7 vs. RCA - 1.8 ± 0.6, p = 0.01), as well as highest rate of VPs (LAD – 80%, CXA – 46.6%, RCA – 70%, p = 0.01). No difference was registered between coronary arteries on the presence of SCs (p = 0.670), NRS (p = 0.455), PR (p = 0.833), but LAPs were more frequently located in the LAD (p = 0.0009). Conclusions Coronary plaques located in the RCA were more voluminous and exhibited a higher volume of lipid rich and non-calcified atheroma. However, compared to the RCA and CXA, the left anterior descending artery presented CPs with a more expressed degree of vulnerability, a higher number of vulnerability markers per plaque, and a higher incidence of LAP. </jats:sec

P1437 Integrated ST segment elevation score as a new predictor of the myocardial scar extent determined with LGE-CMR at 1-month follow-up after STEMI

Abstract Funding Acknowledgements Funded by the research grant PlaqueImage, contract number 26/01.09.2016, SMIS code 103544, by the European Union and the Government of Romania Background The inflammatory response in the acute phase of a myocardial infarction, as well as in later phases contributes to the healing process of the infarcted myocardium and the left ventricular remodeling. Restoration and improvement of LV function highly depends on the magnitude of scar formation. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging has been validated for an accurate determination of the myocardial scar size and transmurality. The recovery of ST segment elevation is a liable marker of vessel patency following PCI. Purpose The aim of the study was to validate a new integrated score of ST segment elevation score (ISSTE) as a new predictor of the myocardial scar tissue size, in relation with increased inflammatory biomarkers, with the extent of myocardial fibrosis at one month, assessed with LGE-CMR, after STEMI. Methods We included 65 patients with STEMI who underwent urgent revascularization with PCI in the first 12 hours from the onset of symptoms. The ISSTE was determined by summing the ST segment elevation in all registered ECG leads at presentation (ISSTE-1) and at 2 hours (ISSTE-2) after primary PCI. Blood samples were also collected at baseline and day-5 for determination of serum hs-CRP levels. At 1-month follow-up all patients under LGE-CMR (1.5T scanner) for evaluation of the myocardial scar extent (volume, percentage, transmurality). Results ISSTE-2 was significantly correlated with day-5 hs-CRP serum levels (r = 0.546, 95%CI: 0.030-0.832, p = 0.037), although no significant correlations were noted with baseline hs-CRP levels (r= 0.238, p = 0.407). There were no significant correlations between ISSTE-1 score and the myocardial scar percentage (r = 0.241, p = 0.11) or high transmurality volume (r = 0.194, p = 0.21), while ISSTE-2 significantly correlated with myocardial scar mass (r = 0.406, 95%CI: 0.107-0.637 p = 0.007) and high transmurality volume (r = 0.344, 95%CI: 0.0320-0.596, p = 0.0273). The restoration of the ST segment, reflected by the difference between ISSTE-1 and ISSTE -2 is correlated with the infarct size mass (r = 0.336, 95%CI: 0.0307 -0.584, p = 0.027). Conclusion The magnitude of ST segment elevation determined at 2 hours after PCI was associated with the inflammatory response at day 5 after STEMI and it may serve as a predictor for the extent of the myocardial scar tissue determined with LGE-CMR at 1 month following STEMI. The ISSTE-1 score calculated at presentation does not reflect extent of the affected myocardial tissue following PCI. </jats:sec

P821 Influence of periplaque fat on coronary plaque vulnerability, a comparative analysis between atherosclerotic lesions located in the right versus left coronary arteries

Abstract Funding Acknowledgements Research grant PlaqueImage, contract number 26/01.09.2016, SMIS code 103544, Project funded by the European Union and the Government of Romania Background The role of epicardial adipose tissue on coronary plaque vulnerability has been well established. However, the role of periplaque fat (PPF) has not been elucidated so far. Moreover, there is scarce data on the role of plaque location, in relation to peri-atheromatous adipose tissue on the vulnerability degree and morphology of coronary atherosclerotic lesions. Purpose To evaluate the influence of PPF on coronary plaque vulnerability, in a comparative analysis between atherosclerotic lesions located in the right and left coronary arteries. Methods This is an observational study which included 82 patients with stable CAD, who underwent 128-multislice CT coronary angiography, presented at least one coronary lesion with at least 50% degree of stenosis and exhibited ≥1 vulnerability markers in the respective coronary plaque. Plaques presenting features of vulnerability (spotty calcifications – SC, Napkin ring sign – NRS, low attenuation plaque – LAP, positive remodeling – PR), were defined as vulnerable plaques (VP). Image postprocessing was performed with the Syngo.via Frontier software and PPF was measured 10 mm around the analyzed VP. Based to the plaque location within the coronary tree, the study subjects were divided into: group 1 (location of VP in the right coronary artery - RCA) - n = 17; group 2 (location of VP in the left coronary artery - LCA) - n = 65. Results The analysis of the plaque characteristics indicated that the VPs from the RCA were significantly longer (20.81± 6.45 vs. 17.37 ± 4.59 mm, p = 0.02) and had a larger volume (269.3± 120.4 vs. 161.6 ± 80.89 mm3, p &amp;lt; 0.0001) compared to the VPs from the LCA. Compared to group 2, coronary plaques in group 1 exhibited a higher vulnerability degree, illustrated by a larger non-calcified volume (232.5 ± 111 vs. 134.5 ± 83.29 mm3, p = 0.0006), lipid-rich volume (19.4 ± 19.07 vs. 10.27 ± 17.08 mm3, p = 0.0106), and fibro-fatty volume (213 ± 101.3 vs. 124.2 ± 7.98 mm3, p = 0.0009). The PPF was significantly larger in VPs from the RCA (0.92 ± 0.48 mm3 vs. 0. 57± 0.34 mm3, p = 0.0041) compared to VPs located in the LCA. No differences were found regarding the total epicardial fat between the two groups (p = 0.386). Conclusions Atherosclerotic plaques located in the RCA exhibited a higher number of vulnerability characteristics compared to those located in the left coronary system and PPF was more pronounced in the regions surrounding VPs located within the RCA. This difference in vulnerability features could be explained not only by geometrical and hemodynamical characteristics of the coronary circulation, but also by inflammation-mediated alteration of endothelial shear stress triggered by release of inflammatory mediators from the local epicardial fat. </jats:sec