Masamichi Iwasaki

Stabilizing effect of combined eicosapentaenoic acid and statin therapy on coronary thin-cap fibroatheroma

BACKGROUND The addition of highly purified eicosapentaenoic acid (EPA) to statin therapy prevents cardiovascular events. However, the impact of this treatment on vulnerable plaques remains unclear. The aim of this study was to assess the impact of adding EPA to a standard statin therapy on vulnerable plaques by serial optical coherence tomography (OCT). METHODS Forty-nine non-culprit thin-cap fibroatheroma (TCFA) lesions in 30 patients with untreated dyslipidemia were included. Patients were randomly assigned to EPA (1800 mg/day) + statin (23 TCFA, 15 patients) or statin only (26 TCFA, 15 patients) treatment. The statin (rosuvastatin) dose was adjusted to achieve a target low-density lipoprotein (LDL) level of <70 mg/dL. Post-percutaneous intervention and 9-month follow-up OCT were performed to evaluate morphological changes of TCFAs. The EPA/arachidonic acid (EPA/AA) ratio and pentraxin-3 (PTX3) levels were also evaluated. RESULTS Despite similar follow-up LDL levels, the EPA + statin group had higher EPA/AA ratios and lower PTX3 levels than the statin group. OCT analysis showed that the EPA + statin group had a greater increase in fibrous-cap thickness, with a greater decrease in lipid arc and lipid length. Macrophage accumulation was less frequently detected in the EPA + statin group than in the statin group at follow-up. When the patients were categorized according to their follow-up PTX3 tertiles, fibrous-cap thickness showed significant increase, and the incidence of macrophages accumulation decreased with lower PTX3 levels. CONCLUSION The concomitant use of EPA and rosuvastatin may stabilize vulnerable plaques better than the statin alone, possibly by suppressing arterial inflammation.

Effect of Daily Glucose Fluctuation on Coronary Plaque Vulnerability in Patients Pre-Treated With Lipid-Lowering Therapy: A Prospective Observational Study

OBJECTIVES This study sought to investigate the effect of daily glucose fluctuation on coronary plaque properties in patients with coronary artery disease (CAD) pre-treated with lipid-lowering therapy. BACKGROUND There is growing evidence that glucose fluctuation, as a residual risk apart from dyslipidemia, is an important factor contributing to the development of CAD. METHODS This prospective study enrolled 70 consecutive CAD patients who were referred for percutaneous coronary intervention and whose low-density lipoprotein cholesterol level was <120 mg/dl under statin treatment or <100 mg/dl without statins. Daily glucose fluctuation was analyzed by measuring the mean amplitude of glycemic excursion (MAGE). The plaque properties in the culprit and nonculprit lesions were assessed by virtual histology intravascular ultrasound, and the volume percentage of necrotic core within the plaque (%NC) and the presence of thin-cap fibroatheroma were evaluated. RESULTS In total, 165 lesions were evaluated in 70 patients (40 diabetic and 30 nondiabetic patients). %NC was well correlated with MAGE (r = 0.490, p <0.001). A linear mixed effect model showed that MAGE had the strongest effect on %NC (coefficient β = 0.080 ± 0.020 [standard error], p < 0.001). The generalized linear mixed effect model revealed that MAGE was the only independent predictor of the presence of thin-cap fibroatheroma (odds ratio: 1.037; 95% confidence interval: 1.010 to 1.065; p = 0.007). CONCLUSIONS Daily glucose fluctuation may have an effect on coronary plaque vulnerability in patients with CAD pre-treated with lipid-lowering therapy. Further investigations should address the rationale for the early detection and control of glucose fluctuation in the era of universal statin use for CAD patients.

The impact of in-stent neoatherosclerosis on long-term clinical outcomes: an observational study from the Kobe University Hospital optical coherence tomography registry

AIMS Although pathological studies have indicated the development of neoatherosclerosis (NA) after stenting, its risk factors and impact on future clinical events remain unclear. We aimed to clarify the possible risk factors for NA development and to evaluate the impact of NA in a large Japanese observational OCT database of patients with coronary heart disease. METHODS AND RESULTS One hundred and seventy-five consecutive patients (314 lesions) who underwent OCT examination >1 year after bare metal or drug-eluting stent implantation were enrolled. We assessed the presence of NA by follow-up OCT and compared adverse clinical events between NA+ and NA- patients. Forty-six patients had NA at the follow-up OCT. These patients had higher low-density lipoprotein (LDL) cholesterol and C-reactive protein (CRP) levels at follow-up. In multivariate logistic analysis, LDL cholesterol and CRP levels at follow-up were independently associated with the presence of NA (odds ratio [OR]: 1.022, p=0.008, OR 1.022, p=0.001, respectively). Moreover, patients with NA had a higher incidence of major adverse cardiac events (MACE) at follow-up. Multivariate Cox hazard analysis showed that the presence of NA was an independent risk factor for MACE (hazard ratio: 2.909, p=0.012). CONCLUSIONS High LDL cholesterol and CRP levels may be risk factors for NA development in patients treated with coronary stents. Moreover, the presence of NA was independently associated with MACE, suggesting the need for careful clinical follow-up of these patients.

Comparisons of detailed arterial healing response at seven months following implantation of an everolimus- or sirolimus-eluting stent in patients with ST-segment elevation myocardial infarction

BACKGROUND The difference of arterial healing response following everolimus-eluting stent (EES) or sirolimus-eluting stent (SES) implantation in patients with ST-segment elevated myocardial infarction (STEMI) has not been compared in detail. METHODS Thirty-five patients with STEMI were randomly implanted with an EES or SES (23 EES, 12 SES). At seven months, neointimal thickness (NIT) and strut malapposition were evaluated by optical coherence tomography (OCT) and the grade and heterogeneity of neointimal coverage (NIC) and development of intra-stent thrombi were evaluated by angioscopy. RESULTS No significant differences were noted in clinical events experienced by the two groups, although one patient with an EES died following a papillary muscle rupture and one patient with a SES experienced sub-acute stent thrombosis. On OCT, although the EES implants showed a greater NIT than the SES implants (94.8 ± 88.8 μm vs 65.6 ± 63.3 μm, P<0.0001), both the EES and SES showed an excellent suppression of neointimal proliferation in the culprit lesion of STEMI. The frequency of uncovered and malapposed struts of EES was significantly lower than that of SES (2.7% vs. 15.7%, P<0.0001, 0.7% vs. 2.3%, P<0.0001, respectively). The ratio of stents fully covered with neointima of EES group was significantly higher than that of SES group (P=0.04). Angioscopic analysis also showed greater dominant NIC grade with homogenous NIC in EES than in SES (P=0.03, P=0.0002, respectively). The incidence of massive intra-stent thrombus of EES was lower than that of SES (P=0.05). CONCLUSION For patients with STEMI, EES may promote better arterial healing response than SES.

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.

Possible association between non-invasive parameter of flow-mediated dilatation in brachial artery and whole coronary plaque vulnerability in patients with coronary artery disease.

BACKGROUND Despite being a relatively widely-used non-invasive parameter of endothelial dysfunction, little is known regarding the relationship between flow-mediated dilatation (FMD) and coronary plaque vulnerability in patients with coronary artery disease (CAD). METHODS 111 CAD patients (age; 68.9 ± 9.3) who underwent both coronary intervention and FMD were enrolled. Spectral analyses of intravascular ultrasound radiofrequency data for both culprit and non-culprit lesions were performed using Virtual Histology software. Plaque burden was described based on fibrotic, fibro-fatty, dense calcium, and necrotic core (NC) components, and thin-cap fibroatheroma (TCFA) was defined as focal NC rich (> 10%) plaques touching the lumen with a percent-plaque volume exceeding 40%. RESULTS Averaged %FMD was 2.86 ± 2.03% (median 2.27%, 25th 1.40%, 75th 4.20%). NC volumes were negatively correlated with log%FMD for both culprit and non-culprit lesions (P = 0.001, r = 0.31 and P = 0.03, r = 0.21, respectively). We divided the patients into three tertiles according to %FMD; 38 were lower (≤ 1.75%), 41 were middle (> 1.75%, but ≤ 3.5%), and 32 were upper tertile (> 3.5%). The prevalence rate of TCFA increased with decreasing %FMD tertile and the incidence of major adverse cardiac events was significantly higher in lower %FMD tertile. Multivariate logistic regression analyses showed that the most powerful predictive factor for TCFA was log%FMD (P < 0.0001), and ROC curve analysis identified %FMD of < 2.81% (AUC = 0.82, sensitivity: 91.2%, specificity: 66.7%) as the optimal cut-off point for predicting the presence of TCFA. CONCLUSIONS Impaired endothelial function in brachial arteries may be associated with whole coronary plaque vulnerability and poor clinical outcome in patients with CAD.

Analysis by Optical Coherence Tomography of Long-term Arterial Healing After Implantation of Different Types of Stents

BACKGROUND Although drug-eluting stents have significantly reduced the midterm incidence of target lesion revascularization (TLR), in vivo studies on long-term vessel healing of sirolimus-eluting stents (SESs) and paclitaxel-eluting stents (PESs) are limited. The aim of this study was to compare long-term arterial healing with SESs and PESs. METHODS We evaluated 27 SESs (23 patients) and 21 PESs (20 patients) by serial optical coherence tomography at 6 months (midphase) and ≥ 3 years (late phase) after stenting and evaluated the change of neointimal thickness (NIT), the percentages of uncovered and malapposed struts, peristrut low-intensity area (region around stent struts with a homogeneously lower intensity appearance than surrounding tissue), thrombus, and atherogenic neointima. RESULTS At follow-up, most SESs showed a progressive increase in the average NIT, whereas PESs showed variable changes. Between midphase and late phase, NIT increased significantly in SESs (midphase, 94.1 ± 49.3; late phase, 130.2 ± 78.7; P = 0.001) but decreased significantly in PESs (midphase, 167.4 ± 122.9; late phase, 136.0 ± 77.7; P = 0.04). The percentages of uncovered struts decreased significantly in SESs; conversely, variable changes were observed in PESs. Peristrut low-intensity area and thrombus formation decreased in SESs but remained largely unchanged in PESs. The prevalence of atherogenic neointima was greater in the late phase than in the midphase in both groups but was similar for both stents. CONCLUSIONS Long-term vessel healing was different for SESs and PESs. Progressive vessel healing was consistently observed in SESs, whereas a heterogeneous process of delayed vessel healing was noted for PESs.

Impact of cytochrome P450 2C19 loss-of-function polymorphism on intra-stent thrombi and lesion outcome after everolimus-eluting stent implantation compared to that after first-generation drug-eluting stent implantation

BACKGROUND The contribution of clopidogrel response due to cytochrome P450 (CYP) 2C19 loss-of-function polymorphism after drug-eluting stent (DES) implantation is unclear. METHODS A total of 196 patients who had undergone optical coherence tomography (OCT) at 8 months following first-generation DES (120 lesions) and current-generation everolimus-eluting stent (EES) implantation (127 lesions) were enrolled. Patients were divided into 3 groups by CYP2C19 polymorphism: extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs). OCT findings were compared among the 3 groups. Responsiveness to clopidogrel was assessed by VerifyNow platelet reactivity unit (PRU). RESULTS The incidence of intra-stent thrombi was significantly higher after first-generation DES implantation compared with EES implantation (35% vs 13%, respectively; p=0.0001). In the first-generation DES group, the incidence of intra-stent thrombi significantly increased among EMs, IMs, and PMs (21% vs 36% vs 63%, respectively; p=0.007), while there was no significant difference among the 3 groups after EES implantation (10% vs 13% vs 20%, respectively; p=0.55). The PRU significantly increased among EMs, IMs, and PMs in each stent group. In multivariate analyses, although PMs had a 3-fold higher risk of thrombi formation compared with non-PMs after first-generation DES implantation, there were no significant differences in thrombi formation between the 2 groups after EES implantation. The optimal PRU cutoff values for the prediction of intra-stent thrombi with first-generation DES and EES were 234 and 256, respectively. CONCLUSION CYP2C19 loss-of-function polymorphism is associated with a higher incidence of intra-stent thrombi after first-generation DES implantation, while the impact is attenuated following EES implantation.

Impact of hemodialysis on local vessel healing and thrombus formation after drug-eluting stent implantation

BACKGROUND Although hemodialysis (HD) is a suggested risk factor for stent thrombosis, its contribution to local vessel healing after drug-eluting stent (DES) implantation is unclear. METHODS A total of 121 patients (152 lesions treated with DES) who underwent 8-month follow-up coronary angiography with optical coherence tomography (OCT) were enrolled, and the findings were compared between patients with and without HD. To match baseline differences, mid-term OCT findings of 42 propensity score-matched lesions (21 non-HD vs. 21 HD) were compared. Effects of HD on the efficacy of antiplatelet therapy were also evaluated by VerifyNow assay (Accumetrics, San Diego, CA, USA). RESULTS Patients with HD had a significantly higher rate of thrombus formation than those without (64% vs. 33%, p = 0.007), although the baseline parameters and lesion characteristics differed between the groups. Multivariate logistic regression analysis revealed that HD was associated with an increased risk of thrombus formation (odds ratio 5.991, 95% confidence interval: 1.972-18.199, p = 0.002). Even after propensity-matching for patient background and balancing of angiographic and OCT variables, the risk of thrombus formation remained significantly higher in HD patients. The P2Y12-reaction unit was significantly increased after HD (Pre HD: 211 ± 75 vs. Post HD: 262 ± 59, p = 0.01), but patients without HD showed no increase during the same elapsed time (221 ± 88 vs. 212 ± 96, p = 0.19). CONCLUSIONS HD is a potential risk factor for subclinical thrombus attachment after DES therapy. Systemic problems, such as residual platelet reactivity, associated with HD as well as local vessel features in HD patients might contribute to the increased incidence of thrombus attachment and subsequent onset of thrombotic event after DES implantation.

Paraoxonase-1 activity affects the clopidogrel response in CYP2C19 loss-of-function carriers

BACKGROUND The impact of paraoxonase-1 (PON1) activity on the response to clopidogrel may differ in patients treated with drug-eluting stents (DES) in association with CYP2C19 loss-of-function (LOF) polymorphisms. METHODS This study included 112 Japanese patients receiving clopidogrel (75 mg/day) and aspirin (100mg/day) who underwent optical coherence tomography (OCT) examination 9 months after DES implantation. The CYP2C19 genotype was analyzed and LOF carriers (1/2, 1/3, 2/2, 3/3, 2/3) were identified. At the 9-month follow-up, platelet reactivity was determined by measuring the P2Y12 reactivity unit (PRU) using a VerifyNow P2Y12 assay, PON1 activity was evaluated and intra-stent thrombus was evaluated by OCT. RESULTS Of the 112 Japanese patients, 75 were LOF carriers (67.0%). The patients were divided into tertiles according to the PON1 activity (tertile 1; <230 U/L, tertile 2; 230-283U/L, tertile 3; >283 U/L). In the VerifyNowP2Y12 analysis, tertile 1 had a higher PRU than tertiles 2 and 3 in LOF carriers, and there was no difference among tertiles in non-carriers. The highest incidence of intra-stent thrombus was observed in tertile 1 followed by tertiles 2 and 3 in LOF carriers, whereas there was no such difference in non-carriers. Multivariate analysis revealed that LOF carriers and PON1 activity tertile 1 were independent predictors of intra-stent thrombus in all patients. In LOF carriers, tertile 1 was the only independent predictor for intra-stent thrombus. CONCLUSION Low PON1 activity is associated with a low response to clopidogrel and a high frequency of intra-stent thrombus only in LOF carriers.