H. M. Garcia-Garcia

AIMS: To evaluate the feasibility of the combined use of virtual histology (VH)-intravascular ultrasound (IVUS) and optical coherence tomography (OCT) for detecting in vivo thin-cap fibroatheroma (TCFA). METHODS AND RESULTS: In 56 patients with angina, 126 plaques identified by IVUS findings were analysed using both VH-IVUS and OCT. IVUS-derived TCFA was defined as an abundant necrotic core (>10% of the cross-sectional area) in contact with the lumen (NCCL) and %plaque-volume >40%. OCT-derived TCFA was defined as a fibrous cap thickness of <65 microm overlying a low-intensity area with an unclear border. Plaque meeting both TCFA criteria was defined as definite-TCFA. Sixty-one plaques were diagnosed as IVUS-derived TCFA and 36 plaques as OCT-derived TCFA. Twenty-eight plaques were diagnosed as definite-TCFA; the remaining 33 IVUS-derived TCFA had a non-thin-cap and eight OCT-derived TCFA had a non-NCCL (in discord with NCCL visualized by VH-IVUS, mainly due to misreading caused by dense calcium). Based on IVUS findings, definite-TCFA showed a larger plaque and vessel volume, %plaque-volume, higher vessel remodelling index, and greater angle occupied by the NCCL in the lumen circumference than non-thin-cap IVUS-derived TCFA. Conclusion Neither modality alone is sufficient for detecting TCFA. The combined use of OCT and VH-IVUS might be a feasible approach for evaluating TCFA.

Atherosclerosis is the main cause of coronary heart disease, which is today the leading cause of death worldwide and will continue to be the first in the world in 2030. In the formation of atherosclerotic coronary lesions, a critical primary step is the accumulation and oxidation of low-density lipoprotein (LDL) particles. Oxidized-LDL favours leucocyte recruitment and their activation, as well as cell death. This leads to generation of complex atherosclerotic plaques. These plaques have a high content of necrotic core, a thin inflamed fibrous cap (intense accumulation of macrophages) and scarce presence of smooth muscle cells (i.e. thin-capped fibroatheroma). At early stages of the formation of the atheroma, the remodelling of the vessel wall usually prevents plaque from encroaching on the lumen, thereby masking the presence of atheroma on angiography. In contrast, greyscale intravascular ultrasound can fully assess the extension of the disease axially and longitudinally. This intravascular imaging technique has played a vital role in advancing our understanding of the pathophysiology of coronary artery disease, and in the development of novel cardiovascular drugs and device therapies. This intravascular imaging technology and its clinical and research applications are discussed in more detail below.

AIMS: To investigate the outcome of a real world diabetic patient cohort treated with bare metal stents (BMS), sirolimus-, or paclitaxel-eluting stents (SES and PES, respectively). Due to the different mechanisms of action of both drugs it is currently unknown which device is the best option to treat these high-risk patients. METHODS AND RESULTS: The study compares the 2-year clinical outcome of 708 consecutive diabetic patients (25% insulin treated) treated with either a BMS (n = 252), a SES (n = 206), or a PES (n = 250), as part of the RESEARCH and T-SEARCH registries. Target vessel revascularization was 19.5% in the BMS group, vs. 15.3% in the SES group and 9.7% in the PES group. PES (21.2%), but not SES (28.9%), were superior to BMS (29.7%) in reducing major adverse cardiac events. After propensity analyses, none of the differences remained significant. The incidence of stent thrombosis (ST) was high in both DES groups. CONCLUSION: There was a trend towards a more favourable outcome associated with the use of PES over BMS. There was no significant difference between SES and PES in each of the clinical endpoints, and neither in the NIDDM patients, which are hypothesized to be better-off with PES.

BACKGROUND: The long-term results after second generation everolimus eluting bioresorbable vascular scaffold (Absorb BVS) placement in small vessels are unknown. Therefore, we investigated the impact of vessel size on long-term outcomes, after Absorb BVS implantation. METHODS: In ABSORB Cohort B Trial, out of the total study population (101 patients), 45 patients were assigned to undergo 6-month and 2-year angiographic follow-up (Cohort B1) and 56 patients to have angiographic follow-up at 1-year (Cohort B2). The pre-reference vessel diameter (RVD) was <2.5 mm (small-vessel group) in 41 patients (41 lesions) and ≥2.5 mm (large-vessel group) in 60 patients (61 lesions). Outcomes were compared according to pre-RVD. RESULTS: At 2-year angiographic follow-up no differences in late lumen loss (0.29±0.16 mm vs 0.25±0.22 mm, p=0.4391), and in-segment binary restenosis (5.3% vs 5.3% p=1.0000) were demonstrated between groups. In the small-vessel group, intravascular ultrasound analysis showed a significant increase in vessel area (12.25±3.47 mm(2) vs 13.09±3.38 mm(2) p=0.0015), scaffold area (5.76±0.96 mm(2) vs 6.41±1.30 mm(2) p=0.0008) and lumen area (5.71±0.98 mm(2) vs 6.20±1.27 mm(2) p=0.0155) between 6-months and 2-year follow-up. No differences in plaque composition were reported between groups at either time point. At 2-year clinical follow-up, no differences in ischaemia-driven major adverse cardiac events (7.3% vs 10.2%, p=0.7335), myocardial infarction (4.9% vs 1.7%, p=0.5662) or ischaemia-driven target lesion revascularisation (2.4% vs 8.5%, p=0.3962) were reported between small and large vessels. No deaths or scaffold thrombosis were observed. CONCLUSIONS: Similar clinical and angiographic outcomes at 2-year follow-up were reported in small and large vessel groups. A significant late lumen enlargement and positive vessel remodelling were observed in small vessels.

OBJECTIVES: The purpose of this study was to assess the occurrence, predictors, and mechanisms of optical coherence tomography (OCT)-detected coronary evaginations following drug-eluting stent (DES) implantation. BACKGROUND: Angiographic ectasias and aneurysms in stented segments have been associated with a risk of late stent thrombosis. Using OCT, some stented segments show coronary evaginations reminiscent of ectasias. METHODS: Evaginations were defined as outward bulges in the luminal contour between struts. They were considered major evaginations (MEs) when extending ≥3 mm along the vessel length, with a depth ≥10% of the stent diameter. A total of 228 patients who had sirolimus (SES)-, paclitaxel-, biolimus-, everolimus (EES)-, or zotarolimus (ZES)-eluting stents implanted in 254 lesions, were analysed after 1, 2, or 5 years; and serial assessment using OCT and intravascular ultrasound (IVUS) was performed post-intervention and after 1 year in 42 patients. RESULTS: Major evaginations occurred frequently at all time points in SES (∼26%) and were rarely seen in EES (3%) and ZES (2%, P = 0.003). Sirolimus-eluting stent implantation was the strongest independent predictor of ME [adjusted OR (95% CI) 9.1 (1.1-77.4), P = 0.008]. Malapposed and uncovered struts were more common in lesions with vs. without ME (77 vs. 25%, P < 0.001 and 95 vs. 20%, P < 0.001, respectively) as was thrombus [49 vs. 14%, OR 7.3 (95% CI: 1.7-31.2), P = 0.007]. Post-intervention intra-stent dissection and protrusion of the vessel wall into the lumen were associated with an increased risk of evagination at follow-up [OR (95% CI): 2.9 (1.8-4.9), P < 0.001 and 3.3 (1.6-6.9), P = 0.001, respectively]. In paired IVUS analyses, lesions with ME showed a larger increase in the external elastic membrane area (20% area change) compared with lesions without ME (5% area change, P < 0.001). CONCLUSION: Optical coherence tomography-detected MEs are a specific morphological footprint of early-generation SES and are nearly absent in newer-generation ZES and EES. Evaginations appear to be related to vessel injury at baseline; are associated with positive vessel remodelling; and correlate with uncoverage, malapposition, and thrombus at follow-up.