Determinants and long-term outcomes of largely uncovered struts in thin-struts drug-eluting stents assessed by optical coherence tomography.

BACKGROUND: Uncovered struts are a determinant of stent failure. The impact of plaque composition and procedural factors on the occurrence, evolution, and outcomes of uncovered struts in a high-risk setting has not been investigated. OBJECTIVE: To investigate the determinants and long-term clinical impact of largely uncovered struts (LUS) in thin-struts drug-eluting stents (DES) implanted in complex lesions by intracoronary optical coherence tomography (OCT). METHODS: Ninety patients with multivessel disease undergoing staged complete revascularization were randomly assigned to bioabsorbable or durable polymer DES. OCT were serially performed during the index procedure, at 3- and 18-month follow-up, and analyzed by an independent core lab. Struts were defined uncovered by OCT if no tissue was visible above the struts. LUS were defined as ≥30% of uncovered struts at 3-month follow-up. Clinical outcomes were the occurrence of target vessel failure (TVF) and major adverse cardiac and cerebrovascular events (MACCE) at 5-year follow-up. RESULTS: LUS occurred in 31 patients (34.4%) regardless of stent platform. At 5 years, no differences were observed in the rate of TVF (12.7% vs. 13.4%; p = 0.91) and MACCE (23.9% vs. 24.9%; p = 0.88) between the two groups. At multivariate logistic regression, plaque rupture, mean lumen diameter, proximal reference vessel area, and maximum stent deployment pressure were independent predictors of LUS. CONCLUSIONS: LUS are a frequent finding in complex coronary lesions treated with thin-struts DES, especially in the presence of plaque rupture. However, in this study, no significant safety signal related to LUS emerged in long-term follow-up.

Temporal course of vascular healing and neoatherosclerosis after implantation of durable- or biodegradable-polymer drug-eluting stents.

Aims: Delayed healing and endothelial dysfunction may occur with drug-eluting stents (DES), promoting accelerated infiltration of lipids in the neointima and development of neoatherosclerosis (NA). Pathology data suggest durable polymer (DP) of DES to play a major role in this process. Whether biodegradable polymer (BP) may address these issues is uncertain. We compared in vivo vessel healing and NA of current generation BP- or DP-DES using serial optical coherence tomography (OCT) assessments. Methods and results: Ninety patients with multivessel coronary artery disease were randomized 1:1 to BP everolimus-eluting stents (EES, Synergy) or DP zotarolimus-eluting stents (ZES, Resolute Integrity). Co-primary endpoints were the maximum length of uncovered struts at 3 months (powered for non-inferiority) and the percentage of patients presenting with frames of NA at 18 months (powered for superiority) as measured by OCT. The maximum length of uncovered struts at 3 months was 10 ± 8 mm in the BP-EES group and 11 ± 7 mm in the DP-ZES group (mean difference -1 mm; upper 97.5% confidence interval +2 mm; P = 0.05 for non-inferiority; P = 0.45 for superiority). The percentage of patients presenting with frames of NA at 18 months was low and similar between BP-EES and DP-ZES groups (11.6% vs. 15.9%; P = 0.56). There was no stent thrombosis in both groups at 24 months. Conclusion: BP-EES and DP-ZES showed a similar healing response at 3 months and a low incidence of NA at 18 months. Biocompatible polymers, regardless of whether they are durable or biodegradable, may favourably impact the long-term vascular response to current-generation DES.

Optical Coherence Tomography Findings in Patients With Coronary Stent Thrombosis: A Report of the PRESTIGE Consortium (Prevention of Late Stent Thrombosis by an Interdisciplinary Global European Effort).

BACKGROUND: Stent thrombosis (ST) is a serious complication following coronary stenting. Intravascular optical coherence tomography (OCT) may provide insights into mechanistic processes leading to ST. We performed a prospective, multicenter study to evaluate OCT findings in patients with ST. METHODS: Consecutive patients presenting with ST were prospectively enrolled in a registry by using a centralized telephone registration system. After angiographic confirmation of ST, OCT imaging of the culprit vessel was performed with frequency domain OCT. Clinical data were collected according to a standardized protocol. OCT acquisitions were analyzed at a core laboratory. Dominant and contributing findings were adjudicated by an imaging adjudication committee. RESULTS: Two hundred thirty-one patients presenting with ST underwent OCT imaging; 14 (6.1%) had image quality precluding further analysis. Of the remaining patients, 62 (28.6%) and 155 (71.4%) presented with early and late/very late ST, respectively. The underlying stent type was a new-generation drug-eluting stent in 50.3%. Mean reference vessel diameter was 2.9±0.6 mm and mean reference vessel area was 6.8±2.6 mm2. Stent underexpansion (stent expansion index <0.8) was observed in 44.4% of patients. The predicted average probability (95% confidence interval) that any frame had uncovered (or thrombus-covered) struts was 99.3% (96.1-99.9), 96.6% (92.4-98.5), 34.3% (15.0-60.7), and 9.6% (6.2-14.5) and malapposed struts was 21.8% (8.4-45.6), 8.5% (4.6-15.3), 6.7% (2.5-16.3), and 2.0% (1.2-3.3) for acute, subacute, late, and very late ST, respectively. The most common dominant finding adjudicated for acute ST was uncovered struts (66.7% of cases); for subacute ST, the most common dominant finding was uncovered struts (61.7%) and underexpansion (25.5%); for late ST, the most common dominant finding was uncovered struts (33.3%) and severe restenosis (19.1%); and for very late ST, the most common dominant finding was neoatherosclerosis (31.3%) and uncovered struts (20.2%). In patients presenting very late ST, uncovered stent struts were a common dominant finding in drug-eluting stents, and neoatherosclerosis was a common dominant finding in bare metal stents. CONCLUSIONS: In patients with ST, uncovered and malapposed struts were frequently observed with the incidence of both decreasing with longer time intervals between stent implantation and presentation. The most frequent dominant observation varied according to time intervals from index stenting: uncovered struts and underexpansion in acute/subacute ST and neoatherosclerosis and uncovered struts in late/very late ST.

Relationship between Serum Inflammatory Biomarkers and Thrombus Characteristics in Patients with ST Segment Elevation Myocardial Infarction.

OBJECTIVES: To compare angiographic and optical coherence tomography (OCT) data pertinent to thrombi, along with the histologic characteristics of aspirated thrombi in patients presenting with ST elevation myocardial infarction (STEMI) with or without inflammation, as assessed by C-reactive protein (CRP) and myeloperoxidase (MPO). METHODS: In the OCTAVIA (Optical Coherence Tomography Assessment of Gender Diversity in Primary Angioplasty) study, 140 patients with STEMI referred for primary percutaneous intervention were enrolled. The patients underwent OCT assessment of the culprit vessel, along with blood sampling of CRP and MPO, and histologic analysis of the thrombus. RESULTS: Biomarkers were available for 129 patients, and histology and immunohistochemistry of the thrombi were available for 78 patients. Comparisons were made using the median thresholds of CRP and MPO (2.08 mg/L and 604.124 ng/mL, respectively). There was no correlation between CRP and MPO levels in the whole population (p = 0.685). Patients with high CRP levels had higher thrombus grades and more frequent TIMI flow 0/1 compared with those with low CRP levels (5 [1st quartile 3; 3rd quartile 5] vs. 3.5 mg/L [1; 5], p = 0.007, and 69.3 vs. 48.5%, p = 0.04, respectively). Patients with high MPO levels more commonly had early thrombi than had those with low MPO levels (42.5 vs. 20.0%, p = 0.04). CONCLUSIONS: CRP and MPO were not correlated in STEMI patients, possibly reflecting different pathogenic mechanisms, with CRP more related to thrombus burden and MPO to thrombus age.

Impact of Culprit Plaque and Atherothrombotic Components on Incomplete Stent Apposition in Patients With ST-Elevation Myocardial Infarction Treated With Everolimus-Eluting Stents　- An OCTAVIA Substudy.

BACKGROUND: The role of culprit plaque and related atherothrombotic components on incomplete stent apposition (ISA) occurrence after primary percutaneous coronary intervention (p-PCI) is unknown. METHODS AND RESULTS: ST-segment elevation myocardial infarction (STEMI) patients undergoing p-PCI with an everolimus-eluting stent were prospectively investigated with optical coherence tomography (OCT) of the infarct-related artery before, after stenting and at 9 months. OCT data, aspirated thrombus and serum inflammatory biomarkers were analyzed. 114 patients with 114 lesions were evaluated. Acute ISA occurred in 82 lesions (71.9%), preferentially in larger vessels with a median area of 0.2 mm(2). The presence of thrombus before stent implantation (odds ratio (OR) 5.5, 95% confidence interval (CI) [1.1-26.9], P=0.04) and the lipid content in the target segment (OR 1.3, 95% CI [1.0-1.5], P=0.04) independently predicted acute ISA. At 9-month follow-up, ISA persisted in 46 lesions (56.1%). The volume of acute ISA significantly predicted persistent ISA (OR 1.3, 95% CI [1.1-1.5], P=0.01). Late-acquired ISA occurred in 39 lesions (34.2%) with a median area of 0.3 mm(2). Red/mixed thrombus before stent implantation (OR 3.7, 95% CI [1.0-13.3], P=0.05) and length of the underlying ruptured plaque (OR 1.7, 95% CI [1.1-2.8] P=0.02) were independently associated with late-acquired ISA. CONCLUSIONS: In STEMI patients, culprit plaque and atherothrombotic components of the infarct-related artery significantly contribute to the onset of acute and late ISA. ISA persistence at follow-up depends on the initial volume of acute ISA.

Impact of different stent alloys on human vascular response to everolimus-eluting stent: an optical coherence tomography study: the OCTEVEREST.

BACKGROUND: New generation drug-eluting stents (DES) incorporate thinner struts and novel alloys to improve clinical performance. Nevertheless, the impact of novel stent materials and designs on human vascular response to DES remains elusive. We sought to evaluate the in-vivo coronary artery response to platinum-chromium (PtCr) versus cobalt-chromium (CoCr) stents featuring the same durable polymer and antiproliferative drug by optical coherence tomography (OCT). METHODS AND RESULTS: A total of 42 patients with de novo lesions in native coronary vessels was treated with PtCr-everolimus eluting stent (EES; n = 21) or CoCr-EES (n = 21). Angiography, intravascular ultrasound, and OCT were performed at the index procedure and 6-month follow-up. PtCr-EES and CoCr-EES had similar concentric expansion (stent eccentricity index; median 0.91 vs. 0.90, respectively, P = 0.47) and very low rate of strut malapposition (median 1.15 vs. 1.80%, P = 0.92) at post implantation. Proportion of struts embedded in tissue was lower in PtCr-EES compared to CoCr-EES (median 2.67 vs. 15.23%, P < 0.001). The primary prespecified end point, the percentage of uncovered struts per patient at 6 months follow-up, was 8.46% [interquartile range (IQR) = 3.05-17.26] in PtCr-EES and 5.88% (IQR = 1.35-13.27) in CoCr-EES (P = 0.36), whereas malapposed struts were observed in 0.00% (IQR = 0.00-0.25) versus 0.48% (IQR = 0.00-1.44), respectively, (P = 0.10). Strut-level neointimal thickness did not differ between the two platforms (median 0.09 vs. 0.08 mm, P = 0.49). CONCLUSIONS: Acute and mid-term responses to EES using PtCr or CoCr platforms were similar, with concentric stent expansion, low malapposition, similar strut coverage and limited amount of neointima. Conversely, at postprocedure, PtCr-EES had fewer embedded struts compared with CoCr-EES.

The role of optical coherence tomography in clarifying the mechanisms for dobutamine stress echocardiography-induced takotsubo cardiomyopathy.

Takotsubo cardiomyopathy is a clinical disorder characterized by a transient dilatation and akynesis or dyskinesis of the left ventricular (LV) apex, mimicking an anterior wall acute myocardial infarction in the absence of significant coronary artery disease (CAD). It typically occurs during an episode of severe emotional or physical stress. Recent reports suggested the potential of dobutamine stress echocardiography (DSE) in inducing the aforementioned syndrome. The transient dysfunction of the LV does not fit any known coronary distribution. Furthermore, there is no obstructive CAD demonstrated at angiography to account for the observed dysfunction. Consequently, the pathophysiology of this syndrome is still undetermined. Here, we report a case of DSE-induced Takotsubo cardiomyopathy in which high-resolution intracoronary imaging was utilized to exclude possible vessel alterations to help provide potential mechanistic explanations for the development of this condition.

Strut coverage and late malapposition with paclitaxel-eluting stents compared with bare metal stents in acute myocardial infarction: optical coherence tomography substudy of the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) Trial.

BACKGROUND: The safety of drug-eluting stents in ST-segment elevation myocardial infarction (STEMI) continues to be debated. Pathological studies have demonstrated an association between uncovered struts and subsequent stent thrombosis. Optical coherence tomography can detect stent strut coverage in vivo on a micron-scale level. We therefore used optical coherence tomography to examine strut coverage in patients with STEMI treated with paclitaxel-eluting stents (PES) and bare metal stents (BMS). METHODS AND RESULTS: In the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, patients with STEMI were randomized 3:1 to PES or BMS implantation. In a formal substudy, optical coherence tomography at 13 months was performed in 118 consecutive randomized patients (89 PES, 29 BMS) in whom 188 stents were assessed (146 PES and 42 BMS). A total of 44 139 stent struts were analyzed by an independent core laboratory blinded to stent assignment. The primary prespecified end point, the percentage of uncovered stent struts per lesion at follow-up, was 1.1 ± 2.5% in BMS lesions versus 5.7 ± 7.0% in PES lesions (P < 0.0001). Malapposed struts were observed in 0.1 ± 0.2% of BMS lesions versus 0.9 ± 2.1% of PES lesions (P = 0.0003). Percentage net volume obstruction was 36.0 ± 15.4% with BMS and 19.2 ± 11.3% with PES (P < 0.0001). CONCLUSIONS: In patients with STEMI undergoing primary percutaneous coronary intervention, implantation of PES as compared with BMS significantly reduces neointimal hyperplasia but results in higher rates of uncovered and malapposed stent struts as assessed by optical coherence tomography at 13-month follow-up. Further studies are required to determine the clinical significance of these findings. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00433966.

Optical Coherence Tomography to Assess Proximal Side Optimization Technique in Crush Stenting.

Aim: The aim of this study was to explore the potential intraprocedural benefits of the Proximal Side Optimization (PSO) technique by Optical Coherence Tomography (OCT). Methods: A case series of 10 consecutive true bifurcation lesions, with severe long pathology of long side branch (SB), were randomly assigned to be treated by standard DK Crush procedure (non-PSO group) as compared to DK Crush in PSO modification (PSO group). The data from OCT investigation before crushing of the SB Drug-Eluting Stent (DES), after crushing, after first kissing balloon inflation (KBI), and after final angiography were compared between the two groups (Public trials registry ISRCTN23355755). Results: All 10 cases were successfully treated by the assigned technique. The two groups were similar in terms of indications for the procedure, bifurcation angle, and stent dimensions. As compared to the non-PSO, the PSO group showed larger proximal SB stent areas (5.8 ± 1.8 vs. 4.5 ± 0.5 mm2; p = 0.02), the larger delta between distal and proximal stent areas before crush (1.5 ± 0.7 vs. 0.6 ± 0.5 mm2; p = 0.004), and the larger Space of Optimal Wiring (SOW) after Crush (5.3 ± 1.8 vs. 2.5 ± 1.1 mm2; p = 0.02). The gaps in scaffolding within the ostial segment of the Side Branch DES were found in two patients from the non-PSO group. Conclusion: The DK Crush in PSO modification results in larger SB DES and SOW areas with better apposition to the vessel wall. As result, the SB DES acquires a funnel shape, which reduces the risk of passage outside the SB stent struts during re-wiring, thus, allowing predictable and secure results.

Coronary Artery Perforation, Subepicardial Hematoma, and Cardiac Tamponade After Complex Percutaneous Coronary Intervention.

This report presents the case of fissured subepicardial hematoma and cardiac tamponade after coronary artery perforation during a complex percutaneous intervention. Surgical therapy was required to achieve hemostasis because a percutaneous sealing result was insufficient. Prompt recognition and cardiac surgery availability are essential for patient survival in such situations. (Level of Difficulty: Beginner.).

Optical coherence tomography: high resolution intravascular imaging to evaluate vascular healing after coronary stenting.

The risk of late stent thrombosis represents a major concern for patients treated with drug-eluting stents (DES). Delayed healing and incomplete stent coverage were commonly observed in pathologic specimens of vessels treated with DES. In-situ assessment of the stent coverage has been limited by the low spatial resolution of current image modalities. Optical coherence tomography (OCT) enables real-time, full tomographic, in-vivo visualization of coronary vessel microstructure. Struts coverage and vessel response of DES compared to BMS are the most immediate clinical applications of OCT. Thickness of coverage and strut apposition can be quantified at micron-scale level with a resolution 10-30 times higher than conventional intravascular ultrasound. Current clinical experience demonstrates the high level of accuracy of OCT in evaluating the heterogeneity of vascular healing following DES implantation. Neointimal coverage at strut level assessed by OCT seems a reasonable intermediate endpoint to quickly scrutinize in preregistration studies the safety profile of the next generation of DES. Major limitations of current OCT technology are shallow depth of light penetration and the need to occlude the vessel for blood removal. Second generation forms of OCT, which allow images to be recorded faster (congruent with 10 times) during a nonocclusive flush, have been recently developed. Full, quick scan of multiple and long stent without occlusion balloon is possible. Further technical advancements are expected to provide sharper images with additional contrast and tissue texture characterization. The value of these improvements must be gauged by the degree of impact in DES technology and patient care.

Spontaneous coronary artery dissection in a middle-age woman: percutaneous treatment guided by intracoronary imaging techniques.

: Angiographic diagnosis and treatment of spontaneous coronary artery dissection is challenging. Complementary use of intracoronary imaging can provide information to guide percutaneous treatments, particularly in these challenging settings. Here we report a case of a 52-year-old woman presenting with an anterior ST-segment elevation myocardial infarction caused by a spontaneous, long, and spiral dissection of the left anterior descending artery. Intracoronary imaging allowed us to visualize the entry port of the coronary dissection which was not sealed by the first angio-guided stenting. This case demonstrates that, beyond merely diagnostic information, the intracoronary imaging is able to provide information to guide percutaneous treatments, particularly in challenging settings in which coronary angiography reveals its limitations.

How to perform distal anchoring technique by 6French radial approach in complex coronary procedures.

Despite remarkable advances in the interventional landscape, device delivery during percutaneous coronary intervention (PCI) can still present technical challenges especially when performed in complex anatomical settings and through radial approach. To overcome difficult coronary stent delivery, several strategies have been developed. A niche option in such complex cases is the anchoring balloon technique, which involves inflation of a balloon non-coaxially in a side branch or distally to the target lesion in a coaxial fashion, to facilitate stent delivery. However, the main limitation of this technique is the requirement of a large guide catheter (≥7French) which may preclude the use of radial approach. We describe, step-by-step, the distal anchoring ballooning technique performed by a 6Fr radial approach to overcome the stent delivery failure in complex anatomical scenarios and to safely and successfully carry out the PCI procedures.

The OPTIS Integrated System: real-time, co-registration of angiography and optical coherence tomography.

The efficacy of an IVUS-guided stent implantation strategy to improve acute results and clinical outcome has been described previously. OCT is another technique which allows high-resolution intracoronary imaging. However, the use of invasive imaging modalities to guide PCI has, as yet, played a limited role in current clinical practice. This may be partly explained by the expertise required for interpretation and clinical decision making. We present a novel technology which enables real-time co-registration of OCT images with angiography. This will simplify matching cross-sectional images to their geographic position on the angiogram, thereby facilitating imaging-guided PCI.

Percutaneous Coronary Intervention Planning and Optimization with Optical Coherence Tomography.

Coronary angiography confirms or excludes coronary artery disease, assesses lesions severity, and helps to decide percutaneous coronary interventions (PCI). Coronary angiography has clear limitations. Intravascular imaging guides PCI. Frequency domain optical coherence tomography (OCT) gained attention for accurate planning and guidance of complex PCI. High-speed OCT image acquisition enables prompt vessel assessment in stable and unstable patients. The high-resolution images provide precise tissue characterization and a reliable quantitative assessment of the coronary pathology. Immediately after stent implantation, OCT allows accurate evaluation of stent expansion and symmetry. Real-time angio-OCT co-registration integrates OCT into the PCI workflow for accurate decision making.

Radiation Therapy-Induced Cardiovascular Disease Treated by a Percutaneous Approach.

We report the case of a 51-year-old woman, treated with radiotherapy at the age of two years, for a pulmonary sarcoma. Subsequently she developed severe aortic stenosis and bilateral ostial coronary artery disease, symptomatic for dyspnea (NYHA III functional class). Due to the prohibitive surgical risk, she underwent successful stenting in the right coronary artery and left main ostia with drug eluting stents and, afterwards, transcatheter aortic valve replacement with transfemoral implantation of a 23 mm Edwards SAPIEN XT valve. The percutaneous treatment was successful without complications and the patient is in NYHA II functional class at 2 years' follow-up, fully carrying out normal daily activities.

Perioperative management of oral antiplatelet therapy and clinical outcomes in coronary stent patients undergoing surgery. Results of a multicentre registry.

The aim was to investigate the perioperative risk of ischaemic and bleeding events in patients with coronary stents undergoing cardiac and non-cardiac surgery and how these outcomes are affected by the perioperative use of oral antiplatelet therapy. This was a multicentre, retrospective, observational study conducted in patients with coronary stent(s) undergoing cardiac or non-cardiac surgery. The primary efficacy endpoint was the 30-day incidence of major adverse cardiac events (MACE), defined as the composite of cardiac death, myocardial infarction (MI) or stroke. The primary safety endpoint was the 30-day incidence of Bleeding Academic Research Consortium (BARC) bleeding ≥ 2. A total of 666 patients were included. Of these, 371 (55.7 %) discontinued their antiplatelet medication(s) (all or partly) before undergoing surgery. At 30 days, patients with perioperative discontinuation of antiplatelet therapy experienced a significantly higher incidence of MACE (7.5 % vs 0.3 %, p< 0.001), cardiac death (2.7 % vs 0.3 %, p=0.027), and MI (4.0 % vs 0 %, p< 0.001). After adjustment, peri-operative antiplatelet discontinuation was the strongest independent predictor of 30-day MACE (odds ratio [OR]=25.8, confidence interval [CI]=3.37-198, p=0.002). Perioperative aspirin (adjusted OR 0.27, 95 % CI 0.11-0.71, p=0.008) was significantly associated with a lower risk of MACE. The overall incidence of BARC ≥ 2 bleeding events at 30-days was significantly higher in patients who discontinued oral antiplatelet therapy (25.6 % vs 13.9 %, p< 0.001). However, after adjustment, antiplatelet discontinuation was not independently associated with BARC ≥ 2 bleeding. In conclusion antiplatelet discontinuation increases the 30-day risk of MACE, in patients with coronary stents undergoing cardiac and non-cardiac surgery, while not offering significant protection from BARC≥ 2 bleeding.

Eroded Versus Ruptured Plaques at the Culprit Site of STEMI: In Vivo Pathophysiological Features and Response to Primary PCI.

OBJECTIVES: The aim of this study was to evaluate the pathophysiological features and response to primary percutaneous coronary intervention (PCI) of nonruptured/eroded plaque versus ruptured plaque as a cause of ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Autopsy series identified nonruptured/eroded plaque and ruptured plaque as the principal pathological substrates underlying coronary thrombosis in STEMI. The real incidence of different plaque morphologies, associated biological factors, superimposed thrombus, and their interaction with primary PCI remain largely unknown. METHODS: In a prospective study, 140 patients with STEMI underwent optical coherence tomography of the infarct-related artery (IRA) before PCI, after everolimus-eluting stent implantation and at 9-month follow-up. Histopathology and immunohistochemistry of thrombus aspirates and serum biomarkers were assessed at baseline. RESULTS: Culprit plaque morphology was adjudicated in 97 patients: 32 plaques (33.0%) with an intact fibrous cap (IFC), 63 (64.9%) plaques with a ruptured fibrous cap (RFC), and 2 (2.1%) spontaneous dissections. Patients with an IFC and RFC had similar clinical characteristics, and serum inflammatory and platelets biomarkers. An IFC presented more frequently with a patent IRA (56.2% vs. 34.9%; p = 0.047), and had fewer lipid areas (lipid-rich areas: 75.0% vs. 100.0%; p < 0.001) and less residual thrombus before stenting (white thrombus: 0.41 mm(3) vs. 1.52 mm(3); p = 0.001; red thrombus: 0 mm(3) vs. 0.29 mm(3); p = 0.001) with a lower peak of creatine kinase-myocardial band (66.6 IU/l vs. 149.8 IU/l; p = 0.025). At the 9-month optical coherence tomography, IFC and RFC had similar high rates of stent strut coverage (92.5% vs. 91.2%; p = 0.15) and similar percentage of volume obstruction (12.6% vs. 10.2%; p = 0.27). No significant differences in clinical outcomes were observed up to 2 years. CONCLUSIONS: In the present study, an IFC was observed at the culprit lesion site of one-third of STEMIs. IFC, compared with RFC, was associated with higher rates of patent IRA at first angiography, fewer lipid areas, and residual endoluminal thrombus. However, no difference in vascular response to everolimus-eluting stent was observed. (Optical Coherence Tomography Assessment of Gender Diversity in Primary Angioplasty [OCTAVIA]; NCT01377207).