Diagnostic Accuracy of Pre-Transcatheter Aortic Valve Replacement Nitroglycerin-Free Fractional Flow Reserve-Computed Tomography-Based Physiological Assessment in Patients With Severe Aortic Stenosis for Predicting Post-Transcatheter Aortic Valve Replacement Ischemia.

BACKGROUND: Fractional flow reserve-computed tomography (FFRCT) has not been validated in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) for coronary artery disease due to theoretical difficulties in using nitroglycerin for such patients.Methods and Results: In this single-center study, we prospectively enrolled 21 patients (34 vessels) and performed pre-TAVR FFRCTwithout nitroglycerin, pre-TAVR invasive instantaneous wave-free ratio (iFR) measurements, and post-TAVR FFR measurements using a pressure wire. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of pre-TAVR FFRCT≤0.80 to predict post-TAVR invasive FFR ≤0.80 were 82%, 83%, 82%, 71%, and 90%, respectively. A receiver operating characteristic analysis demonstrated an optimal cutoff of 0.78 for pre-TAVR FFRCTto indicate post-TAVR FFR ≤0.80, with an area under the curve (AUC) of 0.84, and the counterpart cutoff of pre-TAVR iFR was 0.89 with an AUC of 0.86. CONCLUSIONS: FFRCTwithout nitroglycerin could be a useful non-invasive imaging modality for assessing the severity of coronary artery lesions in patients with severe AS.

Assessment of Residual Vasospasm in Patients with Plaque Rupture or Plaque Erosion using Optical Coherence Tomography.

AIMS: Coronary vasospasm is associated with acute coronary syndrome (ACS) and may persist during primary percutaneous coronary intervention (PCI). We aimed to elucidate the incidence, morphological characteristics, and prognostic impact of residual vasospasm in plaque rupture (PR) and plaque erosion (PE) lesions using optical coherence tomography (OCT). METHODS: We enrolled 142 patients with ACS who underwent OCT-guided primary PCI. All patients received intracoronary vasodilators before OCT examination. Residual vasospasm was identified as intimal gathering and categorised as polygonal- or wavy- patterned depending on the luminal shape. A wavy pattern was defined as a curved intimal surface line. A polygonal pattern was defined as a lumen with multiple angles. The incidence of major cardiovascular events, defined as death, non-fatal myocardial infarction, stroke, and any revascularization, within 1-year of PCI was identified. RESULTS: The prevalence of residual vasospasm in PR and PE was 15.1% (13 of 86) and 21.4% (12 of 56), respectively. Wavy pattern was the major shape of the residual vasospasm. Polygonal-patterned lumen was more frequently observed in PR than in PE (38.5 vs. 8.3 %). The polygonal-patterned lumens had significantly larger lipid arcs (257.9 vs. 78.0 °; P＜0.01), and significantly smaller areas (1.27 vs. 1.88 mm2; P=0.05) than wavy patterned lumens. Residual vasospasm had a prognostic impact on PR but not PE at 1-year of successful primary PCI. CONCLUSION: Considerable proportion of ACS including both PR and PE had residual vasospasm with variable morphological feature and different prognostic impact.

Risk Assessment of Side Branch Compromise After Coronary Bifurcation Stenting　- A Substudy of the 3D-OCT Bifurcation Registry.

BACKGROUND: Side branch (SB) occlusion during bifurcation stenting is a serious complication. This study aimed to predict SB compromise (SBC) using optical coherence tomography (OCT).Methods and Results: Among the 168 patients who enrolled in the 3D-OCT Bifurcation Registry, 111 bifurcation lesions were analyzed to develop an OCT risk score for predicting SBC. SBC was defined as worsening of angiographic SB ostial stenosis (≥90%) immediately after stenting. On the basis of OCT before stenting, geometric parameters (SB diameter [SBd], length from proximal branching point to carina tip [BP-CT length], and distance of the polygon of confluence [dPOC]) and 3-dimensional bifurcation types (parallel or perpendicular) were evaluated. SBC occurred in 36 (32%) lesions. The parallel-type bifurcation was significantly more frequent in lesions with SBC. The receiver operating characteristic curve indicated SBd ≤1.77 mm (area under the curve [AUC]=0.73, sensitivity 64%, specificity 75%), BP-CT length ≤1.8 mm (AUC=0.83, sensitivity 86%, specificity 68%), and dPOC ≤3.96 mm (AUC=0.68, sensitivity 63%, specificity 69%) as the best cut-off values for predicting SBC. To create the OCT risk score, we assigned 1 point to each of these factors. As the score increased, the frequency of SBC increased significantly (Score 0, 0%; Score 1, 8.7%; Score 2, 28%; Score 3, 58%; Score 4, 85%; P<0.0001). CONCLUSIONS: Prediction of SBC using OCT is feasible with high probability.

Optical coherence tomography in coronary atherosclerosis assessment and intervention.

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

Expert consensus statement for quantitative measurement and morphological assessment of optical coherence tomography: update 2022.

In this updated expert consensus document, the methods for the quantitative measurement and morphological assessment of optical coherence tomography (OCT)/optical frequency domain imaging images (OFDI) are briefly summarized. The focus is on the clinical application and the clinical evidence of OCT/OFDI to guide percutaneous coronary interventions.

Reviewing imaging modalities for the assessment of plaque erosion.

Plaque rupture followed by intracoronary thrombus formation is recognized as the most common pathophysiological mechanism in acute coronary syndromes (ACS). The second most common underlying substrate for ACS is plaque erosion whose hallmark is thrombus formation without cap disruption. Invasive and non-invasive methods have emerged as a promising tool for evaluation of plaque features that either predict or detect plaque erosion. Optical coherence tomography (OCT), high-definition intravascular ultrasound (IVUS), near-infrared spectroscopy (NIRS), and near-infrared autofluorescence (NIRF) have been used to study plaque erosion. The detection of plaque erosion in the clinical setting, mainly facilitated by OCT, has shed light upon the complex pathophysiology underlying ACS not related to plaque rupture. Coronary computed tomography angiography (CCTA), which is to date the most commonly used non-invasive technique for coronary plaque evaluation, may also have a role in the evaluation of patients predisposed to erosion. Also, computational models enabling quantification of endothelial shear stress may pave the way to new research in coronary plaque pathophysiology. This review focuses on the recent imaging techniques for the evaluation of plaque erosion including invasive and non-invasive assessment.

Expert consensus statement for quantitative measurement and morphological assessment of optical coherence tomography.

In this document, the methods for the quantitative measurement and morphological assessment of optical coherence tomography (OCT)/optical frequency domain imaging images (OFDI) are briefly summarized. The focus is on the clinical application of OCT/OFDI to guide percutaneous coronary interventions.

The impact of serum trans fatty acids concentration on plaque vulnerability in patients with coronary artery disease: Assessment via optical coherence tomography.

BACKGROUND AND AIMS: Recent epidemiological studies have showed that excessive intake of trans fatty acids (TFA) can be a residual risk for the development of coronary artery disease (CAD) even under medical management, including statins. This study aimed at investigating the association between lipid profile, including serum TFA concentration, and plaque vulnerability using optical coherence tomography (OCT). METHODS: The level of serum elaidic acid, a major TFA component, was measured using gas chromatography in 161 consecutively enrolled patients with CAD under guideline-directed risk factor management. OCT was performed to evaluate morphological features of angiographic intermediate stenosis (30% < diameter of stenosis <70%). OCT data were also used to measure lipid index (LI), defined as mean lipid arc multiplied by lipid length, and determine the presence of thin-cap fibroatheroma (TCFA), defined as a lipid-rich plaque with the smallest fibrous cap thickness <65 µm and the maximal arc >90°. RESULTS: Among 190 lesions assessed using OCT, 49 TCFAs were detected. In patients with at least one TCFA lesion, levels of elaidic acid (12.9 ± 4.9 vs. 10.3 ± 4.3 µmol/L, p = 0.001), triglycerides (169 ± 81 vs. 130 ± 60 mg/dL, p = 0.005), and remnant-like particle cholesterol (10.4 ± 6.5 vs. 7.7 ± 4.7 mg/dL, p = 0.005) were higher than in those without TCFAs. Generalized estimating equations identified elaidic acid level as the independent risk factor of TCFA. LI had a positive correlation with elaidic acid level (r = 0.173, p = 0.025). CONCLUSIONS: TFA may affect plaque vulnerability in patients with CAD. Serum TFA concentration may represent another cardiovascular risk factor during conventional risk factor management.

Assessment of vascular response after drug-eluting stents implantation in patients with diabetes mellitus: an optical coherence tomography sub-study of the J-DESsERT.

Even in the drug-eluting stent era, diabetes mellitus (DM) patients have high incidences of restenosis and repeat revascularization after percutaneous coronary intervention. The aim of this study was to compare vascular response after stent implantation between sirolimus-eluting stent (SES) and paclitaxel-eluting stent (PES) by using optical coherence tomography (OCT) in DM patients as well as in non-DM patients. In the Japan-Drug Eluting Stents Evaluation; a Randomized Trial (J-DESsERT), the OCT sub-study enrolled 75 patients who underwent 8 months follow-up imaging after SES or PES implantation. Mean neointimal hyperplasia (NIH) thickness was significantly thinner in SES than PES in the DM group (77 ± 47 vs. 201 ± 114 µm, p < 0.001) and in the non-DM group (84 ± 37 vs. 212 ± 128 µm, p < 0.001). Unevenness of NIH thickness in longitudinal axis was significantly smaller in SES than PES in the DM group (348 ± 191 vs. 726 ± 385 µm, p < 0.001) and in the non-DM group (344 ± 174 vs. 679 ± 314 µm, p < 0.001). The percentage of uncovered struts was significantly greater in SES than PES in the DM group (24 ± 4 vs. 9 ± 14 %, p < 0.001) and in the non-DM group (16 ± 16 vs. 3 ± 4 %, p = 0.002). Compared with PES, SES showed more potent NIH inhibition in DM patients as well as in non-DM patients.

Two-year vessel healing after everolimus-eluting stent implantation: serial assessment by optical coherence tomography.

BACKGROUND: Previous reports have suggested the importance of delayed arterial healing and the development of neoatherosclerosis as major contributors to stent thrombosis and delayed restenosis. The difference of in vivo assessment of long-term vessel healing between first-generation drug-eluting stents and current generation everolimus-eluting stents (EESs) is limited. The aim of this study was to evaluate long-term arterial healing in EES in comparison with the first generation sirolimus-eluting stents (SES). METHODS: We evaluated 31 EES (23 patients) and 8 SES (7 patients) by serial optical coherence tomography at 12 months (mid-phase) and 24 months (late-phase) after stenting and evaluated the change in neointimal thickness (NIT), the percentages of uncovered struts, peri-strut low intensity area (PLIA; region around stent struts homogenously lower-intensity appearance than surrounding tissue), and thrombus. RESULTS: Although the average NIT showed no significant changes from the mid- to the late-phase follow-up in both EES and SES groups, the change in NIT and minimum lumen area was significantly larger in SES than EES (5.2±29.4 vs. 37.2±48.9; p=0.02, -0.06±0.36 vs. -0.45±0.74; p=0.04, respectively). The incidence of uncovered struts and struts with PLIA of EES was lower than those of SES, at both phases. Stents with in-stent thrombus of EES tended to be lower than that of SES at both phase follow-ups. CONCLUSION: Although both SES and EES showed progressive luminal narrowing from the mid- to the late-phase follow-up, the extent of delayed lumen narrowing and delayed neointimal proliferation was significantly less in the second generation EES than the first generation SES. EESs seem to offer sustained stability in efficacy, without sacrificing safety, up to 2 years after implantation.

Optical coherence tomography and histopathology assessment after implantation of first- and second-generation drug-eluting stents in a porcine coronary model.

BACKGROUND: This study directly compared optical coherence tomography (OCT) and histopathology for the assessment of vascular response to first- and second-generation drug-eluting stents. METHODS AND RESULTS: Sirolimus-, everolimus-, and biolimus-eluting stents (SES, EES, and BES, respectively) were randomly implanted into the coronary arteries of 12 porcine. OCT was conducted after implantation: at 1, 3, and 6 months; histopathology was assessed at 3 and 6 months. At 1-month OCT, EES had the highest neointimal area (NA) and lowest neointimal unevenness score (NUS). At 6 months, NA and NUS were equivalent among the stent types. ∆NA from 1 to 6 months was lowest for EES, and ∆NA correlated with the histopathological inflammation score at 6 months, which was highest for SES (P<0.001). The mean signal intensity (MSI) and the attenuation were different for the stent types at 3 months, and were associated with inflammation score. Moderate diagnostic efficiency for measuring MSI was found, with an optimal cut-off of 6.88 predicting a high (≥grade 3) inflammation score. CONCLUSIONS: EES had the greatest uniformity and the least neointimal proliferation and were associated with less persistent inflammation. OCT provides accurate morphometric data; furthermore, quantitative measurement of the optical properties may help assess histological inflammation, which was more predominantly associated with SES than with EES and BES.

Global endocardial area change rate for the assessment of left ventricular relaxation and filling pressure: using 3-dimensional speckle-tracking study.

Early diastolic mitral inflow and annulus velocities ratio (E/e') is the parameter used to estimate left ventricular (LV) filling pressure, but their use for patients with reduced ejection fraction (EF) (<50 %) is controversial. LV endocardial area change rate with 3-dimensional (3-D) speckle-tracking can be used to evaluate the entire LV diastolic function, we tested the hypothesis that the early diastolic area change rate (E-ACR) represents LV relaxation, and E and E-ACR ratio (E/E-ACR) can accurately predict LV filling pressure in patients with reduced and preserved EF (≥50 %). We studied 125 patients with EF of 40 ± 17 %. E-ACR of all patients was measured using the global area change rate, and LV relaxation time constant (τ, n = 53) and pulmonary capillary wedge pressure (PCWP, n = 125) were measured by cardiac catheterization. E-ACR significantly correlated with τ (r = -0.60, p < 0.001). In the retrospective group (n = 101), E/E-ACR correlated with PCWP for patients with reduced EF as well as those with preserved EF (n = 79 and 22, r = 0.62 and 0.81, both p < 0.001). In overall patients, E/E-ACR ≥94 cm was a better predictor of elevated mean PCWP (>12 mmHg) (sensitivity: 69 %, specificity: 87 %, areas under the curves = 0.82; p < 0.001) and was a more accurate predictor than E/e' (p = 0.001) for the retrospective group. For the validation group (n = 24), E/E-ACR ≥94 cm was similarly predictive for elevated mean PCWP (sensitivity: 60 %, specificity: 100 %, positive predictive value: 100 %, negative predictive value: 78 %). In conclusions, global E-ACR by 3-D speckle-tracking proved to be dependent on LV relaxation. Moreover, E/E-ACR was found to be a powerful predictor of LV filling pressure regardless of EF.

Utility of combining assessment of right ventricular function and right atrial remodeling as a prognostic factor for patients with pulmonary hypertension.

We tested the hypothesis that the addition of right atrial (RA) remodeling to right ventricular (RV) function enhances the capability of the latter to predict long-term outcome for pulmonary hypertension (PH) patients. We studied 82 PH patients, all of whom underwent echocardiography and right heart catheterization. RV function was calculated by averaging the three regional peak speckle-tracking longitudinal strains from RV free wall (RV-free). RA remodeling was assessed as the RA area traced planimetrically at end-systole. Pre-defined cutoffs for RV dysfunction and RA remodeling were RV-free ≤19.4 % and RA area of >18 cm(2), respectively. Long-term unfavorable outcome events were tracked for 2.0 years. RA area correlated with mean RA pressure (r = 0.62, p < 0.001), as well as with tricuspid E/E' (r = 0.38, p = 0.001). Moreover, RA area in patients with RV restrictive filling was significantly larger than that in patients with others (all p < 0.05). Kaplan-Meier analysis revealed that patients with RV-free ≤19.4 % had worse long-term outcomes than those with RV-free >19.4 % (log-rank p = 0.01), as did patients with RA area >18 cm(2) compared with those with RA area ≤18 cm(2) (log-rank p < 0.05). For sequential Cox models, a model based on hemodynamic parameters of RV performance (χ2 = 3.11) was improved by addition of brain natriuretic peptide, World Health Organization functional class (χ2 = 9.24; p < 0.05), and RV-free (χ2 = 17.11; p = 0.005), and further improved by addition of RA area (χ2 = 21.36, p < 0.05). In conclusion, the combined assessment of RV function and RA area results in more accurate prediction of long-term outcome, and may well have clinical implications for better management of PH patients.

Optical coherence tomography and histopathological assessment of delayed arterial healing after drug-eluting stent implant in a pig coronary model.

BACKGROUND: Delayed healing, such as persistent inflammation and fibrin deposition, and vascular dysfunction after drug-eluting stent has been reported. Histological validation of coronary optical coherence tomography (OCT) morphology has not yet been done. METHODS: Sirolimus eluting stents (SES, n=8) and bare metal stents (BMS n=8) were implanted in pig coronary arteries. One month after implantation, an acetylcholine challenge test and OCT were performed. The OCT texture pattern of the neointima was classified into one of the three categories; Layered type, Homo type, and Hetero type. Hearts were harvested for histopathological scoring of inflammation and intramural thrombus. RESULTS: Inflammation and intramural thrombus scores were higher in the Hetero type than in the Layered type and Homo type. OCT intensity of the Homo type was higher than that of the Layered type and Hetero type. Most SES were of the Hetero type. Conversely, most BMS were of the Homo type. SES exhibited higher inflammation and intramural thrombus than BMS (1.72 ± 0.89 vs 1.00 ± 0.00, P=0.0003, 2.39 ± 0.70 vs 0.92 ± 0.28, P<0.001 respectively). After acetylcholine injection, the diameter change was 4.31 ± 4.80% for SES versus -3.68 ± 6.81% for BMS (P=0.024). CONCLUSIONS: The Hetero type texture pattern in OCT images was associated with histological inflammation and intramural thrombus predominantly found in SES, and is related to endothelial dysfunction.

OCT compared with IVUS in a coronary lesion assessment: the OPUS-CLASS study.

OBJECTIVES: The aim of this study was to investigate the reliability of frequency domain optical coherence tomography (FD-OCT) for coronary measurements compared with quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS). BACKGROUND: Accurate luminal measurement is expected in FD-OCT because this technology offers high resolution and excellent contrast between lumen and vessel wall. METHODS: In 5 medical centers, 100 patients with coronary artery disease were prospectively studied by using angiography, FD-OCT, and IVUS. In addition, 5 phantom models of known lumen dimensions (lumen diameter 3.08 mm; lumen area 7.45 mm(2)) were examined using FD-OCT and IVUS. Quantitative image analyses of the coronary arteries and phantom models were performed by an independent core laboratory. RESULTS: In the clinical study, the mean minimum lumen diameter measured by QCA was significantly smaller than that measured by FD-OCT (1.81 ± 0.72 mm vs. 1.91 ± 0.69 mm; p < 0.001) and the minimum lumen diameter measured by IVUS was significantly greater than that measured by FD-OCT (2.09 ± 0.60 mm vs. 1.91 ± 0.69 mm; p < 0.001). The minimum lumen area measured by IVUS was significantly greater than that by FD-OCT (3.68 ± 2.06 mm(2) vs. 3.27 ± 2.22 mm(2); p < 0.001), although a significant correlation was observed between the 2 imaging techniques (r = 0.95, p < 0.001; mean difference 0.41 mm(2)). Both FD-OCT and IVUS exhibited good interobserver reproducibility, but the root-mean-squared deviation between measurements was approximately twice as high for the IVUS measurements compared with the FD-OCT measurements (0.32 mm(2) vs. 0.16 mm(2)). In a phantom model, the mean lumen area according to FD-OCT was equal to the actual lumen area of the phantom model, with low SD; IVUS overestimated the lumen area and was less reproducible than FD-OCT (8.03 ± 0.58 mm(2) vs. 7.45 ± 0.17 mm(2); p < 0.001). CONCLUSIONS: The results of this prospective multicenter study demonstrate that FD-OCT provides accurate and reproducible quantitative measurements of coronary dimensions in the clinical setting.

Noninvasive and simple assessment of cardiac output and pulmonary vascular resistance with whole-body impedance cardiography is useful for monitoring patients with pulmonary hypertension.

BACKGROUND: Right heart catheterization (RHC) is the gold standard for the diagnosis of pulmonary hypertension (PH) and a useful tool for monitoring PH. However, there are some disadvantages in the regular use of RHC because it is invasive. Noninvasive methods for monitoring hemodynamics are needed to manage patients with PH. In this study, we aimed to evaluate the reliability of noninvasive hemodynamic assessment with whole-body impedance cardiography (Non-Invasive Cardiac System [NICaS]) for PH. METHODS AND RESULTS: We investigated 65 consecutive patients undergoing RHC. Two-thirds of them had pulmonary arterial hypertension and one-third had chronic thromboembolic PH; 25% of the patients were receiving medical therapy. Cardiac output (CO) was estimated by NICaS (NI-CO), thermodilution (TD-CO), and the Fick method (Fick-CO). There was a strong correlation between NI-CO and TD-CO (r=0.715, P<0.0001) and Fick-CO (r=0.653, P<0.0001). Noninvasive pulmonary vascular resistance (PVR) was estimated using a conventional invasive equation with NI-CO, mean pulmonary arterial pressure was calculated by echocardiographic measurement, and pulmonary capillary wedge pressure was estimated at 10mmHg in all cases. NICaS-derived PVR was very strongly correlated with invasive PVR (TD-PVR: r=0.704, P<0.0001; Fick-PVR: r=0.702, P<0.0001). CONCLUSIONS: Noninvasive measurement of CO and PVR using NICaS and echocardiography is a useful tool for the assessment of PH.

Qualitative and quantitative assessment of stent restenosis by optical coherence tomography: comparison between drug-eluting and bare-metal stents.

BACKGROUND: We hypothesized that the tissue components of in-stent restenosis (ISR) might differ between drug-eluting stents (DES) and bare-metal stents (BMS) and that these differences could be distinguished by qualitative and quantitative optical coherence tomography (OCT) analyses. METHODS AND RESULTS: One-hundred and twenty-two initial ISR lesions (sirolimus-eluting stents: n=28; paclitaxel-eluting stents: n=51; BMS: n=43) were evaluated with OCT. Based on their OCT appearance, the lesions were classified as homogeneous, layered or heterogeneous. The optical properties of backscatter, attenuation and signal intensity of the neointimal tissue (NIT) were quantified. To evaluate the vascular response after balloon angioplasty (BA), the rate of reduction of the NIT area (NITA) was calculated (NITA before - after BA/NITA before BA at the minimum lumen cross-sectional area). Among the morphologic OCT patterns, the layered type was predominant with DES, whereas lesions were homogeneous with BMS (P<0.001). Backscatter and signal intensity were significantly higher with BMS (P<0.05 and P<0.001 respectively). The NITA reduction rate was significantly greater in the layered and heterogeneous groups than in the homogeneous group (P<0.01). CONCLUSIONS: The morphologic OCT patterns of the NIT in ISR differed significantly between DES and BMS, probably reflecting pathologic differences. Layered and heterogeneous tissues might respond better than homogeneous tissue to simple balloon dilatation, suggesting a possible direction for OCT-based ISR treatment strategies.

Impact of stent platform of paclitaxel-eluting stents: assessment of neointimal distribution on optical coherence tomography.

BACKGROUND: The Taxus Express™ paclitaxel-eluting stent (Express-PES) and Taxus Liberté™ PES (Liberté-PES) have identical drugs, drug doses, and polymers, but different stent platforms. The Liberté-PES platform has thinner struts, specifically designed for more uniform drug elution. METHODS AND RESULTS: Fifty-four patients who underwent 6-month follow-up optical coherence tomography (OCT) after Express-PES (n=27) or Liberté-PES (n=27) implantation were enrolled. Longitudinal and circumferential uniformity of neointimal distribution was evaluated in 3-D by computing mean neointimal thickness (NIT) within 360 equally spaced radial sectors for every 1-mm cross-section. After stenting, intravascular ultrasound showed that Liberté-PES had a significantly smaller maximum angle between adjacent struts, with a tendency toward a lower incidence of % length of the segment with maximum angle >90° than Express-PES. Liberté-PES had a significantly thinner mean NIT than the Express-PES with comparable frequency of uncovered struts. Longitudinal and circumferential absolute variation of NIT expressed by standard deviation of NIT from each sector was significantly smaller for Liberté-PES than for Express-PES. Liberté-PES had a tendency toward a decreased incidence of thrombus and peri-strut low-intensity areas (findings suggestive of delayed arterial healing), compared to Express-PES. CONCLUSIONS: Stent design and thickness appeared to affect neointima suppression of PES. The stent platform of the Liberté-PES may offer greater and more homogeneous reduction of neointimal proliferation spatially across the full length of the PES.