Antonios Karanasos

Everolimus-eluting bioresorbable vascular scaffolds for treatment of patients presenting with ST-segment elevation myocardial infarction: BVS STEMI first study

AIMS We evaluated the feasibility and the acute performance of the everolimus-eluting bioresorbable vascular scaffolds (BVS) for the treatment of patients presenting with ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS The present investigation is a prospective, single-arm, single-centre study, reporting data after the BVS implantation in STEMI patients. Quantitative coronary angiography and optical coherence tomography (OCT) data were evaluated. Clinical outcomes are reported at the 30-day follow-up. The intent-to-treat population comprises a total of 49 patients. The procedural success was 97.9%. Pre-procedure TIMI-flow was 0 in 50.0% of the patients; after the BVS implantation, a TIMI-flow III was achieved in 91.7% of patients and the post-procedure percentage diameter stenosis was 14.7 ± 8.2%. No patients had angiographically visible residual thrombus at the end of the procedure. Optical coherence tomography analysis performed in 31 patients showed that the post-procedure mean lumen area was 8.02 ± 1.92 mm(2), minimum lumen area 5.95 ± 1.61 mm(2), mean incomplete scaffold apposition area 0.118 ± 0.162 mm(2), mean intraluminal defect area 0.013 ± 0.017 mm(2), and mean percentage malapposed struts per patient 2.80 ± 3.90%. Scaffolds with >5% malapposed struts were 7. At the 30-day follow-up, target-lesion failure rate was 0%. Non-target-vessel revascularization and target-vessel myocardial infarction (MI) were reported. A non-target-vessel non-Q-wave MI occurred. No cases of cardiac death or scaffold thrombosis were observed. CONCLUSION In the present series, the BVS implantation in patients presenting with acute MI appeared feasible, with high rate of final TIMI-flow III and good scaffold apposition. Larger studies are currently needed to confirm these preliminary data.

Angiographic and Optical Coherence Tomography Insights Into Bioresorbable Scaffold Thrombosis Single-Center Experience

Background—As bioresorbable vascular scaffolds (BVSs) are being increasingly used in complex real-world lesions and populations, BVS thrombosis cases have been reported. We present angiographic and optical coherence tomography (OCT) findings in a series of patients treated in our center for definite bioresorbable scaffold thrombosis. Methods and Results—Up to June 2014, 14 patients presented with definite BVS thrombosis in our center. OCT was performed in 9 patients at the operator’s discretion. Angiographic and OCT findings were compared with a control group comprising 15 patients with definite metallic stent thrombosis. In the BVS group, time interval from index procedure to scaffold thrombosis ranged from 0 to 675 days. Incomplete lesion coverage by angiography was identified in 4 of 14 cases, malapposition by OCT in 5 of 9 cases, strut discontinuity in 2 of 9 cases, and underexpansion in 2 of 9 cases. Five patients had discontinued dual antiplatelet therapy, and in 3 of them discontinued dual antiplatelet therapy discontinuation had occurred the week preceding the event. There were no significant differences in angiographic or OCT findings between BVS and metallic stent thrombosis. Conclusions—Suboptimal implantation with incomplete lesion coverage, underexpansion, and malapposition comprises the main pathomechanism for both early and late BVS thrombosis, similar to metallic stent thrombosis. Dual antiplatelet therapy discontinuation seems to also be a secondary contributor in several late events. Our observations suggest that several potential triggers for BVS thrombosis could be avoided.

New insights by optical coherence tomography into the differences and similarities of culprit ruptured plaque morphology in non-ST-elevation myocardial infarction and ST-elevation myocardial infarction.

BACKGROUND Plaque rupture is the most common pathology associated with non-ST-elevation myocardial infarction (NSTEMI) and ST-elevation myocardial infarction (STEMI). However, limited data are available regarding ruptured plaque morphology and its relationship with the clinical syndrome. This study aimed (1) to provide a morphologic description of ruptured culprit lesions by optical coherence tomography (OCT) and (2) to investigate whether ruptured plaque morphology differs between NSTEMI and STEMI. METHODS We included 84 consecutive patients with NSTEMI and STEMI undergoing OCT study of the culprit lesion. We identified patients with plaque rupture in the OCT study and used them as the study population. Qualitative and quantitative analysis of ruptured plaque morphology was then performed, followed by a comparison of the morphological characteristics in patients with STEMI and NSTEMI. RESULTS Fifty-five patients (70.5%) with rupture, 25 with NSTEMI, and 30 with STEMI were used for analysis. Plaque was ruptured at the minimal lumen in 34.5% of the cases, whereas 69% of the ruptures occurred at the plaque shoulder. Ruptured cap thickness was ≤90 μm in 96% of ruptured plaques. Patients with NSTEMI had greater minimal luminal area (P < .001), less lipid content (P = .01), and lower rupture length (P < .001) and length of missing fibrous cap (P < .05) compared with patients with STEMI. CONCLUSIONS Rupture of the plaque in myocardial infarction usually occurs in sites different than the minimal lumen and at the shoulder of areas with fibrous cap measuring ≤90 μm. Patients with STEMI have greater plaque disruption and smaller minimal lumen area than patients with NSTEMI.

Chemical denervation of the renal artery by vincristine in swine. A new catheter based technique

BACKGROUND Renal sympathetic denervation is a promising technique for the treatment of resistant hypertension. We evaluated a novel method for chemical sympathetic denervation of the renal artery by local delivery of vincristine, an antineoplastic drug with potential for peripheral neurotoxicity, using a dedicated catheter in an animal model. METHODS Local delivery of vincristine by a specially designed catheter, was performed unilaterally in the renal arteries of 14 juvenile Landrace swine. The procedure was then repeated in the contralateral renal artery using a placebo mixture. Animals were euthanized at 28 days and histological specimens of renal arteries and perirenal arterial stroma containing renal nerves were extracted and sectioned. The number of uninjured nerves in each histological section was then quantified, following identification by immunohistochemical staining. RESULTS In all animals delivery of vincristine and placebo mixtures was successful and uncomplicated. Both vincristine- and placebo-treated renal arteries were angiographically patent at the end of the procedure. The mean number of intact nerves in all sections was significantly lower in the group of vincristine (p<0.05). CONCLUSIONS Catheter-based delivery of vincristine in the renal artery of an experimental model is feasible and results in significant reduction in the number of renal nerves. Our findings warrant further confirmation in animal and human studies.

Optical coherence tomography assessment of the spatial distribution of culprit ruptured plaques and thin-cap fibroatheromas in acute coronary syndrome.

AIMS Plaque rupture and subsequent thrombosis is known to be the most important pathology leading to acute coronary syndrome (ACS). We investigated by optical coherence tomography (OCT) whether in ACS there is an association of the location of the culprit plaque in the coronary tree with plaque rupture and/or thin cap fibroatheroma (TCFA). METHODS AND RESULTS We included 74 patients presenting with ACS that underwent OCT study of the culprit lesion. The distance of the culprit lesion from the ostium was measured angiographically, and the presence of rupture and/or TCFA was assessed by OCT. Sixty-seven patients were analysed. Forty-five ruptured plaques were identified by OCT (67.1%). The distance from the ostium was lower for culprit ruptured plaques versus culprit non-ruptured plaques (p<0.01), particularly in the left anterior descending (LAD) and the left circumflex (LCx) arteries. The majority of culprit ruptured plaques (68.9%) was located in the proximal 30 mm of the coronary arteries. A distance from the ostium of ≤30.54 mm predicted plaque rupture with 71.1% sensitivity and 68.2% specificity. Culprit lesions in the proximal 30 mm are associated with rupture (p<0.05), TCFA (p<0.05), and lower minimal cap thickness (p<0.05). CONCLUSIONS Culprit ruptured plaques in ACS seem to be predominately located in the proximal segments of the coronary arteries.

Morphological Characteristics of Culprit Atheromatic Plaque Are Associated With Coronary Flow After Thrombolytic Therapy: New Implications of Optical Coherence Tomography From a Multicenter Study

OBJECTIVES This study investigated the association between morphological characteristics of culprit atheromatic lesions as assessed by optical coherence tomography and Thrombolysis In Myocardial Infarction (TIMI) flow grade after thrombolysis in patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND Although several variables have been found to predict coronary flow after thrombolysis in patients with STEMI, the impact of culprit lesion morphology has not been studied. METHODS Fifty-five patients with STEMI from 3 tertiary centers that were treated with thrombolysis and underwent optical coherence tomography examination in the culprit lesion between 24 and 48 h after thrombolysis were included in the study. Patients were categorized on the basis of TIMI flow grade into patients with TIMI flow grade 3 versus TIMI flow grade < or =2. RESULTS Patients with TIMI flow grade < or =2 had plaques with more lipid quadrants than patients with TIMI flow grade 3 (p < 0.001), and presented with greater incidence of plaque rupture (p = 0.001). Mean minimal cap thickness was greater in patients with patent arteries than in patients with impaired flow (87 +/- 26 microm vs. 48 +/- 18 microm, p < 0.0001). Minimal cap thickness was independently associated with TIMI flow grade. CONCLUSIONS The morphological characteristics of the culprit atheromatic lesion in patients with STEMI are associated with coronary flow after thrombolysis. The lipid content, the existence of rupture, and mainly the thickness of the fibrous cap are associated with the outcome of thrombolysis.

A novel method to assess coronary artery bifurcations by OCT: cut-plane analysis for side-branch ostial assessment from a main-vessel pullback.

AIMS In coronary bifurcations assessment, evaluation of side-branch (SB) ostia by an optical coherence tomography (OCT) pullback performed in the main branch (MB) could speed up lesion evaluation and minimize contrast volume. Dedicated software that reconstructs the cross-sections perpendicular to the SB centreline could improve this assessment. We aimed to validate a new method for assessing the SB ostium from an OCT pullback performed in the MB. METHODS AND RESULTS Thirty-one sets of frequency-domain OCT pullbacks from 28 patients, both from the MB and the SB of a coronary artery bifurcation were analysed. Measurements of the SB ostium from the SB pullback were used as a reference. Measurements of the SB ostium from the MB pullback were then performed in a laboratory setting by (i) conventional analysis and (ii) cut-plane analysis, and the measurement error for each analysis was estimated. Correlations of SB ostium measurements acquired from the MB pullback in comparison with reference measurements acquired from the SB pullback were higher with cut-plane analysis compared with conventional analysis, albeit not reaching statistical significance (area: rcut-plane = 0.927 vs. rconventional = 0.870, P = 0.256; mean diameter: rcut-plane = 0.918 vs. rconventional = 0.788, P = 0.056; minimum diameter: rcut-plane = 0.841 vs. rconventional = 0.812, P = 0.734; maximum diameter: rcut-plane = 0.770 vs. rconventional = 0.635, P = 0.316). Cut-plane analysis was associated with lower absolute error than conventional analysis (area: 0.56 ± 0.45, vs. 1.50 ± 1.31 mm(2), P < 0.001; mean diameter: 0.18 ± 0.14 vs. 0.44 ± 0.30 mm, P < 0.001). CONCLUSION Measurements of SB ostium performed in a laboratory setting by cut-plane analysis of an OCT pullback of the main branch have high correlation with reference measurements performed in a SB OCT pullback and lower error compared with conventional analysis.

Very late bioresorbable scaffold thrombosis after discontinuation of dual antiplatelet therapy

A 57-year-old gentleman was admitted with unstable angina with dynamic ECG changes (E), 4 days after discontinuation of dual antiplatelet therapy (DAT) with aspirin and clopidogrel. He had undergone staged percutaneous coronary intervention with bioresorbable vascular scaffold (BVS; ABSORB 1.1, Abbott Vascular, Santa Clara, CA, USA) implantation in the ostial left circumflex artery (LCx) 2 years ago ( Panels A–D ), followed by everolimus-eluting metal stent implantation in …

A honeycomb-like structure in the left anterior descending coronary artery: demonstration of recanalized thrombus by optical coherence tomography.

A 41-year-old man presented with atypical chest pain in another hospital with an electrocardiogram negative for ischemia, but with slightly elevated troponin I levels (0.12 ng/ml). The patient underwent cardiac catheterization within 24 h. Coronary angiography revealed 2 nonsignificant lesions at

Calcified nodules: an underrated mechanism of coronary thrombosis?

Coronary thrombosis, typically presenting as acute coronary syndrome, is commonly considered a result of plaque rupture. However, pathologic studies have also suggested other mechanisms, such as plaque erosion and calcified nodules ([1][1]). We present a case of coronary thrombosis in a patient with