Targeting extracellular vesicles to injured tissue using membrane cloaking and surface display.

BACKGROUND: Extracellular vesicles (EVs) and exosomes are nano-sized, membrane-bound vesicles shed by most eukaryotic cells studied to date. EVs play key signaling roles in cellular development, cancer metastasis, immune modulation and tissue regeneration. Attempts to modify exosomes to increase their targeting efficiency to specific tissue types are still in their infancy. Here we describe an EV membrane anchoring platform termed "cloaking" to directly embed tissue-specific antibodies or homing peptides on EV membrane surfaces ex vivo for enhanced vesicle uptake in cells of interest. The cloaking system consists of three components: DMPE phospholipid membrane anchor, polyethylene glycol spacer and a conjugated streptavidin platform molecule, to which any biotinylated molecule can be coupled for EV decoration. RESULTS: We demonstrate the utility of membrane surface engineering and biodistribution tracking with this technology along with targeting EVs for enhanced uptake in cardiac fibroblasts, myoblasts and ischemic myocardium using combinations of fluorescent tags, tissue-targeting antibodies and homing peptide surface cloaks. We compare cloaking to a complementary approach, surface display, in which parental cells are engineered to secrete EVs with fusion surface targeting proteins. CONCLUSIONS: EV targeting can be enhanced both by cloaking and by surface display; the former entails chemical modification of preformed EVs, while the latter requires genetic modification of the parent cells. Reduction to practice of the cloaking approach, using several different EV surface modifications to target distinct cells and tissues, supports the notion of cloaking as a platform technology.

Transcatheter closure of atrial septal defect protects from pulmonary edema: septal occluder device gradually reduces LR shunt.

A 56-year-old woman was diagnosed as atrial septal defect (ASD) with pulmonary hypertension; pulmonary blood flow/systemic blood flow (Qp/Qs) of 2.3, pulmonary artery pressure (PAP) of 71/23(39) mmHg and diastolic dysfunction of left ventricle. PAP was improved after medical therapy; therefore, transcatheter ASD closure was performed. Seven days later, left-sided heart failure occurred, however, the improvement of Qp/Qs (1.7) and PAP of 51/21(32) was confirmed. Diuretic therapy was introduced which led to further decrease of PAP 40/12(25) and Qp/Qs (1.1). Because of gradual decrease of Qp/Qs, this patient appeared to be protected from acute pulmonary edema.

Simultaneous Intravascular Ultrasound Usage Overcomes Misinterpretation When Evaluating Lipid-Rich Plaques With Optical Frequency Domain Imaging--Ex Vivo Study.

BACKGROUND: The aim of this study was to investigate the accuracy of optical frequency domain imaging (OFDI) in lipid-rich plaque detection and determine the causes of "misinterpretation," and evaluate whether these limitations can be overcome with intravascular ultrasound (IVUS) using ex-vivo human coronaries. METHODS AND RESULTS: The OFDI images and corresponding 218 histological segments were evaluated. Segments with a poor signal and diffuse borders on OFDI, classified as lipid-rich plaques, were compared with the histological segments and IVUS images. Using histological images as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value of OFDI for the detection of lipid-rich plaques were 93%, 93%, 85%, and 97%, respectively. The causes of false-positive diagnosis of lipid-rich plaque (11 segments) were superficial macrophage infiltration causing signal attenuation (8/11 segments, 73%) and tangential signal dropout of light (3/11 segments, 27%), whereas the cause of false-negative diagnosis was thickening of the fibrous cap (5 segments, 100%). Simultaneous IVUS helped to correct the misinterpretation of OFDI results and improved the diagnostic accuracy; the sensitivity, specificity, positive predictive value, and negative predictive value of OFDI with adjunct use of IVUS were 96%, 99%, 99%, and 98%, respectively. CONCLUSIONS: OFDI occasionally over- or underestimates the existence of lipid-rich plaques, which may be overcome with adjunctive usage of IVUS.

Coronary angiographic characteristics that influence fractional flow reserve.

BACKGROUND: Percutaneous coronary intervention (PCI) guided with fractional flow reserve (FFR) has been shown to improve clinical outcome. Although coronary angiography is the standard method for PCI guidance, the visual severity of stenosis is not always correlated with functional severity, suggesting that there are additional angiographic factors that affect functional ischemia. METHODS AND RESULTS: To evaluate angiographic predictors of positive FFR in stenotic lesions, angiographic characteristics of 260 consecutive patients (362 lesions) who underwent FFR testing from April 2009 to September 2012 were analyzed. A scoring system (STABLED score) using these predictors was developed and compared with quantitative coronary angiography (QCA). %Diameter stenosis >50% (OR, 8.43; P<0.0001), tandem lesion (OR, 4.00; P<0.0001), true bifurcation (OR, 2.42; P=0.028), lesion length >20 mm (OR, 5.40; P=0.0002), and distance from ostium <20 mm (OR, 1.94; P=0.028) were determined as independent predictors of positive FFR. Area under the ROC curve for probability of positive FFR using the STABLED score (Stenosis 2 points, TAndem lesion 1 point, Bifurcation 1 point, LEsion length 1 point, Distance from ostium 1 point) was 0.85, higher than that for QCA stenosis alone (0.76). STABLED score ≥3 had 72.3% sensitivity and 83.6% specificity for predicting positive FFR, and PPV was 76.7%. CONCLUSIONS: Specific angiographic features are applicable for predicting functional ischemia. STABLED score correlates well with FFR.

[Introduction and PDCA-Management of a Liaison-Clinical Pathway with Cancer Patients after a Curative Operation].

Our hospital was appointed as an Osaka designated cancer care hospital in April 2012. At that time, we introduced the same liaison-clinical pathway with cancer patients after a curative operation in all of Osaka. Based on the management of the plan-do-check-act cycle, we found problems in the clinical pathway. These problems included the following: the clinical pathway was not known, was complicated, was troubling for patients, and not well understood by doctors. To solve these problems, we planned and carried out the following five measures. The first was public information, followed by practice processes, informed consent, patient referral documents, and clinical pathway investigation reports. We were able to promote the use of the liaison-clinical pathway by constantly improving these measures.

Transradial intervention for patients with ST elevation myocardial infarction with or without cardiogenic shock.

OBJECTIVES: To compare clinical outcomes between transradial (TRI) and transfemoral intervention (TFI) in primary percutaneous coronary intervention (PCI) in patients with ST elevation myocardial infarction (STEMI) with or without shock. BACKGROUND: TRI for STEMI has benefits in TRI high volume centers. However, TRI has not been reported for STEMI with shock even in such centers. METHODS: We retrospectively studied 425 STEMI patients who underwent primary PCI. Patients were divided into four groups according to approach site and presence of cardiogenic shock, including TRI without shock (TR group, n = 273), TRI with shock (TRS group, n = 38), TFI without shock (TF group, n = 71), and TFI with shock (TFS group, n = 43). RESULTS: PCI success rates were similar among the four groups. The TR group was superior to the TF group in terms of shorter cath lab to first device activation time, and lower access site complications, and 30-day mortality rates (1.1% vs. 11.3%, P < 0.001). In shock patients, cardiopulmonary arrest was commonly observed in both the TRS and TFS groups (42.1% and 51.2%, respectively). The TRS group showed a trend toward a shorter door to first device activation time compared to the TFS group and lower access site complications; however, 30-day mortality rate was 28.9% in TRS and 25.6% in TFS group (P = 0.7). CONCLUSIONS: In TRI high volume center, TRI for STEMI was safe and feasible as a default approach. TRI could be applied to severe shock patients with similar clinical outcome to TFI.

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.

Transradial coronary angiography with virtual 1 French, sheathless 3 French catheter.

Minimizing catheter size can reduce bleeding complications in coronary angiography. We herein report extreme slender "needle size" (19-G) coronary diagnostic catheterization using a new 3-Fr diagnostic catheter by sheathless method. A 58-year-old man having effort angina underwent coronary angiography. The 3-Fr Ikari Left diagnostic catheter, which is equal to 19-G, was inserted smoothly both for left and right coronary arteries by sheathless method. We only needed 4 min to achieve hemostasis with manual compression after catheter withdrawal in this case.

Peptidyl arginine deiminase inhibition alleviates angiotensin II-induced fibrosis.

OBJECTIVES: The conversion of protein arginine residues to citrulline by calcium-dependent peptidyl arginine deiminases (PADs) has been implicated in the pathogenesis of several diseases, indicating that PADs are therapeutic targets. A recent study indicated that PAD4 regulates age-related organ fibrosis and dysfunction; however, the specific role of this PAD and its citrullination substrate remains unclear. We investigated whether pharmacological inhibition of PAD activity could affect the progression of fibrosis and restore heart function. METHODS: Cardiac hypertrophy was induced by chronic infusion of angiotensin (Ang) II. After 2 weeks of AngII infusion, a PAD inhibitor (Cl-amidine hydrochloride) or vehicle (saline) was injected every other day for the next 14 days together with the continued administration of AngII for a total of up to 28 days. Cardiac fibrosis and remodeling were evaluated by quantitative heart tissue histology, echocardiography, and mass spectrometry. RESULTS: A reverse AngII-induced effect was observed in PAD inhibitor-treated mice (n=6) compared with AngII vehicle-treated mice, as indicated by a significant reduction in the heart/body ratio (AngII: 6.51±0.8 mg/g vs. Cl-amidine: 5.27±0.6 mg/g), a reduction in fibrosis (AngII: 2.1-fold increased vs. Cl-amidine: 1.8-fold increased), and a reduction in left ventricular posterior wall diastole (LWVPd) (AngII: 1.1±0.04 vs. Cl-amidine: 0.78±0.02 mm). Label-free quantitative proteomics analysis of heart tissue indicated that proteins involved in fibrosis (e.g., periostin), cytoskeleton organization (e.g., transgelin), and remodeling (e.g., myosin light chain, carbonic anhydrase) were normalized by Cl-amidine treatment. CONCLUSION: Our findings demonstrate that pharmacological inhibition of PAD may be an effective strategy to attenuate cardiac fibrosis.

Up-Titration of Sacubitril/Valsartan Among Patients With Heart Failure and Preserved Ejection Fraction.

AIMS: In recent large trials, sacubitril/valsartan demonstrated favorable effects in patients with HF. However, many patients do not achieve the target dose of treatment. This study investigated the factors linked to up-titration of sacubitril/valsartan in patients with heart failure and preserved ejection fraction (HFpEF). METHODS: Using a multicenter retrospective database, 204 consecutive patients with HFpEF (left ventricular ejection fraction ≥ 40%) who were treated with sacubitril/valsartan between October 2020 and March 2022 were analyzed. Up-titration was defined as an increase in dosage above 24/26 mg BID beyond 12 weeks after the initiation of sacubitril/valsartan. RESULTS: Among the patients, 55% underwent up-titration, and 8% discontinued the drug. The baseline systolic blood pressure (SBP) was higher in patients with up-titration than in those with no up-titration; SBP values similar to that at baseline were observed between the 2 groups at 2 to 4 weeks and at 12 weeks after the commencement of sacubitril/valsartan treatment. The majority of those who discontinued sacubitril/valsartan did so because of hypotension. The multivariable logistic regression model showed that a history of hypertension, history of atrial fibrillation, baseline SBP, and baseline estimated glomerular filtration rate <60 mL/min/1.73 m2 were associated with sacubitril/valsartan up-titration. CONCLUSION: Approximately half of all patients did not undergo up-titration, and 8% of those with HFpEF discontinued the sacubitril/valsartan therapy. For aggressive up-titration and continuation of sacubitril/valsartan, patients with lower baseline SBP, renal dysfunction, absence of a history of hypertension, and presence of atrial fibrillation may require more careful monitoring.

Rationale and Design of the Effect of Ivabradine on Exercise Tolerance in Patients With Chronic Heart Failure (EXCILE-HF) Trial　- Protocol for a Multicenter Randomized Controlled Trial.

Background: A high resting heart rate is an independent risk factor for mortality and morbidity in patients with cardiovascular diseases. Ivabradine selectively inhibits the funny current (I f) and decreases heart rate without affecting cardiac conduction, contractility, or blood pressure. The effect of ivabradine on exercise tolerance in patients with heart failure with reduced ejection fraction (HFrEF) on standard drug therapies remains unclear. Methods and Results: This multicenter interventional trial of patients with HFrEF and a resting heart rate ≥75 beats/min in sinus rhythm treated with standard drug therapies will consist of 2 periods: a 12-week open-label, randomized, parallel-group intervention period (standard drug treatment+ivabradine group and standard drug treatment group) to compare changes in exercise tolerance between the 2 groups; and a 12-week open-label ivabradine treatment period for all patients to evaluate the effect of adding ivabradine on exercise tolerance. The primary endpoint will be the change in peak oxygen uptake (V̇O2) during the cardiopulmonary exercise test from Week 0 (baseline) to Week 12. Secondary endpoints will be time-dependent changes in peak V̇O2 from Week 0 to Weeks 12 and 24. Adverse events will also be evaluated. Conclusions: The EXCILE-HF trial will provide meaningful information regarding the effects of ivabradine on exercise tolerance in patients with HFrEF receiving standard drug therapies and suggestions for the initiation of ivabradine treatment.

Incremental Value of Global Longitudinal Strain for Confirming Heart Failure-Related Symptoms in Severe Aortic Stenosis.

The indications or timing of aortic valve replacement for symptomatic aortic stenosis (AS) are based on a patient's life expectancy and symptoms. However, clinical decision-making may be difficult because symptoms are subjective and cannot be quantitatively assessed and confirmed. This study aimed to evaluate the association between heart failure (HF)-related symptoms and cardiac hemodynamic left ventricular deformations in patients with severe AS using transthoracic echocardiographic assessments of left ventricular global longitudinal strain (LV-GLS). The medical records of patients hospitalized for AS between February 2017 and September 2019 were retrospectively screened. Independent cardiologists analyzed the transthoracic echocardiographic images of a digital echocardiography database. The cohort comprised 177 hospitalized patients with severe AS and no history of HF. The subgroup with HF-related symptoms included 87 patients, whereas that without HF-related symptoms included 90 patients. In 145 patients without atrial fibrillation, the left atrial volume index (LAVI) and LV-GLS were significantly associated with HF-related symptoms (odds ratio 1.033, 95% confidence interval 1.008 to 1.059, p = 0.011 and odds ratio 1.224, 95% confidence interval 1.118 to 1.340, p <0.0001, respectively). Moreover, the combination of brain natriuretic peptide level, LAVI, and LV-GLS showed better diagnostic accuracy than the combination of brain natriuretic peptide level and LAVI (p = 0.005). However, there were no such tendencies in 32 patients with atrial fibrillation. The HF-related symptoms in patients with severe AS were strongly linked to LV-GLS. LV-GLS showed incremental value for confirming HF-related symptoms.

Relevant adverse events and drug discontinuation of sacubitril/valsartan in a real-world Japanese cohort: REVIEW-HF registry.

BACKGROUND: The characteristics, tolerability, and outcomes in patients with heart failure (HF) who are treated with sacubitril/valsartan remain unclear in Japan. METHODS: We conducted a nationwide multicenter study to evaluate the features and outcomes of patients newly prescribed sacubitril/valsartan for the management of HF. We analyzed adverse events (AEs) related to sacubitril/valsartan at 3 months, which were defined as hypotension, worsening renal function, hyperkalemia, and angioedema. Additionally, the association between AEs and outcomes was examined. RESULTS: Among 993 patients, the mean age was 70 years and 291 (29.3 %) were female, and 22.8 % had left ventricular ejection fraction ≥50 %. Of them, 20.8 % had systolic blood pressure (sBP) <100 mmHg, and 19.5 % had estimated glomerular filtration rate (eGFR) <30 ml/min/1.73 m2 at baseline, which were the populations excluded from the eligibility in landmark trials. AEs related to sacubitril/valsartan were observed in 22.5 % of the patients at 3 months. Overall, 22.6 % of patients discontinued sacubitril/valsartan, and hypotension was the most common event leading to drug discontinuation. After adjustment, patients who had worse HF symptoms (New York Heart Association III or IV), sBP <100 mmHg, and eGFR <30 ml/min/1.73 m2 were associated with a higher risk of AEs related to sacubitril/valsartan. Additionally, patients experiencing AEs had a higher risk of cardiovascular death or HF hospitalization than those who did not. CONCLUSION: In Japan, sacubitril/valsartan was also prescribed to patients not eligible for landmark trials, and AEs were observed at a relatively high rate from soon after treatment initiation. Physicians should closely monitor patients for these events, especially in patients anticipated to have a higher risk of AEs.

Pathological Analysis of Medial and Intimal Calcification in Lower Extremity Artery Disease: Impact of Hemodialysis.

Background: The prevalence and degree of lower extremity artery disease in hemodialysis (HD) patients is higher than in the general population. However, the pathological features have not yet been evaluated. Objectives: The aim of the study was: 1) to compare lesion characteristics of lower extremity artery disease in HD vs non-HD patients; and 2) to determine factors associated with severe medial calcification. Methods: Seventy-seven lower limb arteries were assessed from 36 patients (median age 77 years; 23 men; 21 HD and 15 non-HD) who underwent autopsy or lower limb amputation. Arteries were serially cut at 3- to 4-mm intervals creating 2,319 histological sections. Morphometric analysis and calcification measurements were performed using ZEN software. Calcification with a circumferential angle (arc) ≥180° was defined as severe calcification. Multivariable logistic regression was used to identify risk factors for severe medial calcification. Results: The degree of the medial calcification arc was significantly higher in the HD group compared to the non-HD group (P < 0.0001). In the multivariable analysis, HD was associated with severe medial calcification in below-the-knee lesions (OR: 17.1; P = 0.02). The degree of intimal calcification in above-the-knee lesions was also significantly higher in HD patients with a higher prevalence of advanced atherosclerotic plaque (P = 0.02). The prevalence of severe bone formation was more common in the HD patients (P = 0.01). Conclusions: Hemodialysis patients demonstrated a higher degree of medial and intimal calcification compared with non-HD patients. The difference was more prominent in the medial calcification of below-the-knee lesions.

Determination of lipid-rich plaques by artificial intelligence-enabled quantitative computed tomography using near-infrared spectroscopy as reference.

BACKGROUND AND AIMS: Artificial intelligence quantitative CT (AI-QCT) determines coronary plaque morphology with high efficiency and accuracy. Yet, its performance to quantify lipid-rich plaque remains unclear. This study investigated the performance of AI-QCT for the detection of low-density noncalcified plaque (LD-NCP) using near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS). METHODS: The INVICTUS Registry is a multi-center registry enrolling patients undergoing clinically indicated coronary CT angiography and IVUS, NIRS-IVUS, or optical coherence tomography. We assessed the performance of various Hounsfield unit (HU) and volume thresholds of LD-NCP using maxLCBI4mm ≥ 400 as the reference standard and the correlation of the vessel area, lumen area, plaque burden, and lesion length between AI-QCT and IVUS. RESULTS: This study included 133 atherosclerotic plaques from 47 patients who underwent coronary CT angiography and NIRS-IVUS The area under the curve of LD-NCP<30HU was 0.97 (95% confidence interval [CI]: 0.93-1.00] with an optimal volume threshold of 2.30 mm3. Accuracy, sensitivity, and specificity were 94% (95% CI: 88-96%], 93% (95% CI: 76-98%), and 94% (95% CI: 88-98%), respectively, using <30 HU and 2.3 mm3, versus 42%, 100%, and 27% using <30 HU and >0 mm3 volume of LD-NCP (p < 0.001 for accuracy and specificity). AI-QCT strongly correlated with IVUS measurements; vessel area (r2 = 0.87), lumen area (r2 = 0.87), plaque burden (r2 = 0.78) and lesion length (r2 = 0.88), respectively. CONCLUSIONS: AI-QCT demonstrated excellent diagnostic performance in detecting significant LD-NCP using maxLCBI4mm ≥ 400 as the reference standard. Additionally, vessel area, lumen area, plaque burden, and lesion length derived from AI-QCT strongly correlated with respective IVUS measurements.

CORRIGENDUM: Antiplatelet Effect of Single Antiplatelet Therapy With Prasugrel and Oral Anticoagulation After Stent Implantation in a Rabbit Arteriovenous Shunt Model.

[This corrects the article DOI: 10.1253/circrep.CR-21-0084.].

Antiplatelet Effect of Single Antiplatelet Therapy With Prasugrel and Oral Anticoagulation After Stent Implantation in a Rabbit Arteriovenous Shunt Model.

Background: Antiplatelet therapy following stent implantation in patients requiring oral anticoagulation (OAC) is controversial because triple therapy (i.e., dual antiplatelet therapy [DAPT] with OAC) is associated with a high risk of bleeding. Methods and Results: In this study, 21 rabbits were divided into 5 groups: prasugrel and warfarin (Prasugrel+OAC group); aspirin and warfarin (Aspirin+OAC group); prasugrel, aspirin, and warfarin group (Triple group); prasugrel and aspirin (Conventional DAPT group); and no medication (Control group). The treated groups were administered medication for 1 week. An arteriovenous shunt loop was established from the rabbit carotid artery to the jugular vein and 2 bare metal stents were deployed in a silicone tube. After 1 h of circulation, the volume of thrombi was evaluated quantitatively by measuring the amount of protein. Bleeding time was measured at the same time. The volume of the thrombus (amount of protein) around stent struts was lowest in the Triple group, followed by the Prasugrel+OAC and Conventional DAPT groups, and was highest in the Control group. Bleeding time was the longest in the Triple group, followed by the Aspirin+OAC, Prasugrel+OAC, Conventional DAPT, and Control groups. Conclusions: This study suggests that prasugrel with OAC may be a feasible antithrombotic regimen following stent implantation in patients who require OAC therapy.

Impact of exercise capacity on the long-term incidence of atrial arrhythmias in heart failure.

We sought to demonstrate the impact of improved peak exercise oxygen consumption (V̇O2) during maximal exercise testing after cardiac rehabilitation (CR) on the incidence of arrhythmias in patients with heart failure (HF). The present study comprised of 220 patients with HF, and peak V̇O2 was examined at 2 and 5 months after CR. Of the 220 patients, 110 (50%) had a low peak V̇O2 of < 14 mL/min/kg at 2 months. The peak V̇O2 improved in 86 of these 110 (78%) patients at 5 months after CR. During a median follow-up of 6 years, the patients with improvement in peak V̇O2, compared to those without peak V̇O2 improvement, had a lower rate of mortality (4% vs. 29%, log-rank, P < 0.001) and HF hospitalization (6 vs. 17%, log-rank, P = 0.044) and a lower incidence of new-onset atrial arrhythmias (9 vs. 27%, log-rank, P = 0.013), with no difference in the incidence of ventricular arrhythmias between groups (1 vs. 4%, log-rank, P = 0.309). The majority of deaths in the patients without an improved peak V̇O2 were because of cardiovascular events (73%), particularly progressive HF (55%). Early detection and management of atrial arrhythmias may improve outcomes in patients without peak V̇O2 improvement after CR.

Late neointimal volume reduction is observed following biodegradable polymer-based drug eluting stent in porcine model.

BACKGROUND: The BP-SES has an abluminally applied biodegradable polymer that is fully resorbed after 3-4 months but may have longer-lasting effects. The aim of this study was to determine the long-term vascular response to the novel Ultimaster™ sirolimus-eluting stent (BP-SES). METHODS: BP-SESs, everolimus-eluting stents (DP-EESs), and bare metal stents were implanted in 22 coronary arteries of 15 mini-swine. All animals underwent optical frequent domain imaging (OFDI) to assess neointimal volume and quality at either 1 (n = 7) or 3 (n = 8) months and at 9 (n = 15) months and were euthanized at 9 months. Stents were subsequently histologically investigated to analyze the vascular response and maturity of neointimal tissue according to cell density. RESULTS: OFDI revealed greater regression in neointimal volume from 3 to 9 months with BP-SESs than with DP-EESs (-0.6 ± 0.5 mm2 vs. 0.00 ± 0.4 mm2, p = 0.07). Although there was no significant difference between BP-SESs and DP-EESs in the inflammation score (BMS, BP-SES, and DP-EES: 0.1 ± 0.1, 0.3 ± 0.4, and 0.4 ± 0.4, respectively; p < 0.0001) in histological analysis, BP-SESs showed slightly greater maturity than DP-EESs (1.8 ± 0.3, 1.7 ± 0.3, and 1.6 ± 0.3, p = 0.09). CONCLUSIONS: While both BP-SESs and DP-EESs showed minimal inflammatory responses at 9 months, BP-SESs showed a trend for greater neointimal maturity and regression, which may be related to earlier completion of the vascular response.