Endothelial progenitor cells and plaque burden in stented coronary artery segments: an optical coherence tomography study six months after elective PCI.

BACKGROUND: Endothelial progenitor cells (EPC) are involved in neovascularization and endothelial integrity. They might be protective in atherosclerosis. Optical coherence tomography (OCT) is a precise intracoronary imaging modality that allows assessment of subintimal plaque development. We evaluated the influence of EPC on coronary plaque burden in stable disease and implemented a novel computational plaque analysis algorithm using OCT. METHODS: Forty-three patients (69.8% males, 69.6 ± 7.7 years) were investigated by OCT during re-angiography 6 months after elective stent implantation. Different subpopulations of EPCs were identified by flow cytometry according to their co-expression of antigens (CD34+, CD133+, kinase domain receptor, KDR+). An algorithm was applied to calculate the underlying total plaque burden of the stented segments from OCT images. Plaque morphology was assessed according to international consensus in OCT imaging. RESULTS: A cumulative sub-strut plaque volume of 10.87 ± 12.7 mm3 and a sub-stent plaque area of 16.23 ± 17.0 mm2 were found within the stented vessel segments with no significant differences between different stent types. All EPC subpopulations (mean of EPC levels: CD34+/CD133+: 2.66 ± 2.0%; CD34+/KDR+: 7.50 ± 5.0%; CD34+/CD133+/KDR+: 1.12 ± 1.0%) inversely correlated with the identified underlying total plaque volume and plaque area (p ≤ 0.012). CONCLUSIONS: This novel analysis algorithm allows for the first time comprehensive quantification of coronary plaque burden by OCT and illustration as spread out vessel charts. Increased EPC levels are associated with less sub-stent coronary plaque burden which adds to previous findings of their protective role in atherosclerosis.

Time course of vascular response after an a priori strategy of bare metal stent implantation post-dilated with a paclitaxel-coated balloon: Implementation of a three-dimensional analysis algorithm with optical coherence tomography.

BACKGROUND: An a priori combined therapy of a bare metal stent post-dilated with a paclitaxel- -coated balloon (PCB) was investigated with optical coherence tomography (OCT) at 2 and 6 months regarding vessel response. Previous studies have shown inconsistent results and the time course of vessel healing after such an interventional strategy is unknown. METHODS: Thirty-three de novo lesions in 32 patients were electively treated. Six-month OCT analysis was available in 24 lesions. Two-month OCT follow-up was obtained in 16 lesions. Sequential OCT at 2 and 6 months was available in 7 patients. A novel 3-dimensional picture of vessel segments as spread outs was implemented. RESULTS: Severe incomplete stent apposition (ISA) accompanied by significantly lower strut coverage were found at 2-month compared with 6-month follow-up (ISA struts: 11.4 ± 11.8% vs. 1.8 ± 4.8%, p = 0.001; uncovered struts: 14.5 ± 14.8% vs. 2.0 ± 5.3%, p = 0.001). ISA size diminished over time and the possibly observed phenomenon of positive vessel remodeling (remodeling volume: 4.9 ± 5.9 mm3 at 2-months vs. 2.0 ± 2.6 mm3 at 6-months; p = 0.042) was largely reversible in most lesions. CONCLUSIONS: Bare metal stenting with adjunctive application of paclitaxel by a coated bal-loon shows transient severe incomplete strut apposition, most likely due to focal positive ves-sel remodeling. Thus, caution is needed in bailout situations following a PCB angioplasty. A novel illustration of OCT parameters as "carpet views" enables a comprehensive analysis of investigated stents.

Stent coverage and neointimal proliferation in bare metal stents postdilated with a Paclitaxel-eluting balloon versus everolimus-eluting stents: prospective randomized study using optical coherence tomography at 6-month follow-up.

BACKGROUND: In this randomized trial, strut coverage and neointimal proliferation of a therapy of bare metal stents (BMSs) postdilated with the paclitaxel drug-eluting balloon (DEB) was compared with everolimus drug-eluting stents (DESs) at 6-month follow-up using optical coherence tomography. We hypothesized sufficient stent coverage at follow-up. METHODS AND RESULTS: A total of 105 lesions in 90 patients were treated with either XIENCE V DES (n=51) or BMS postdilated with the SeQuent Please DEB (n=54). At follow-up, comparable results on the primary optical coherence tomography end point (percentage uncovered struts 5.64±9.65% in BMS+DEB versus 4.93±9.29% in DES; P=0.366) were found. Thus, BMS+DEB achieved the prespecified noninferiority margin of 5% uncovered struts versus DES (difference between treatment means, 0.71%; one-sided upper 95% confidence interval, 4.14%; noninferiority P=0.04). Optical coherence tomography analysis showed significantly more global neointimal proliferation in the BMS+DEB group (15.7±7.8 versus 11.0±5.2 mm(3) proliferation volume/cm stent length; P=0.002). No significant focal in-stent stenosis analyzed with angiography (percentage diameter stenosis at follow-up, 22.8±11.9 versus 16.9±10.4; P=0.014) and optical coherence tomography (peak local area stenosis, 39.5±13.8% versus 36.8±15.6%; P=0.409) was found. CONCLUSIONS: Good stent strut coverage of >94% was found in both therapy groups. Despite greater suppression of global neointimal growth in DES, both DES and BMS+DEB effectively prevented clinically relevant focal restenosis at 6-month follow-up. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01056744.

Determinants of neointimal proliferation and stent coverage after intracoronary therapy with drug-eluting devices in stable coronary artery disease: role of endothelial progenitor cells and interleukin-1 family cytokines.

BACKGROUND: Endothelial progenitor cells (EPCs) and cytokines seem to play a pivotal role in arterial healing after stent implantation. Using optical coherence tomography (OCT) as a high-resolution imaging technique, we aimed to assess the influence of circulating EPCs and levels of Il-1 cytokines on stent coverage and in-stent proliferation. METHODS: Eighty-nine patients were randomly treated with either Xience V drug-eluting stent (DES; n = 48) or bare-metal stent (BMS) postdilated with the SeQuent Please drug-eluting balloon (DEB; n = 41). EPC populations (CD34+/CD133+ and CD34+/CD133+/KDR+ EPC) and cytokines (Il-1ra, Il-18, and Il-1α) were measured before percutaneous coronary intervention using flow cytometry or immunoassay. Vessel remodeling was analyzed using coronary angiography and OCT at 6-month follow-up. RESULTS: Indexed neointimal volume and maximal proliferation thickness correlated inversely with EPC levels in the entire study population (r = -0.220; P=.04 and r = -0.253; P=.02) and the BMS + DEB subgroup (r = -0.344; P=.03 and r = -0.374; P=.02). Late lumen loss (LLL) was associated with the proatherogenic Il-18 concentration in the main population (r = 0.342; P=.01) and the BMS + DEB group (r = 0.471; P=.01). In the DES subgroup, associations with proliferation and LLL were lacking. Associations for stent strut coverage were not observed. CONCLUSIONS: A high EPC count seems to be a favorable individual patient factor, since it was associated with less instent proliferation. Contrarily, high Il-18 levels lead to more LLL, which emphasizes its proatherogenic properties.