Nakahisa Kimata
Nippon Medical School
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Circulation-cardiovascular Interventions | 2010
Masamichi Takano; Masanori Yamamoto; Masayuki Mizuno; Daisuke Murakami; Toru Inami; Nakahisa Kimata; Koji Murai; Nobuaki Kobayashi; Kentaro Okamatsu; Takayoshi Ohba; Yoshihiko Seino; Kyoichi Mizuno
Background—Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results—Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 &mgr;m versus 123.0±102.5 &mgr;m; P<0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P=0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P=1.0), the cross sections with ESL increased (9.6% versus 15.2%; P=0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P<0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P=1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions—The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.Background— Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results— Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 μm versus 123.0±102.5 μm; P <0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P =0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P =1.0), the cross sections with ESL increased (9.6% versus 15.2%; P =0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P <0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P =1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions— The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.
Diabetes Care | 2013
Osamu Kurihara; Masamichi Takano; Masanori Yamamoto; Akihiro Shirakabe; Nakahisa Kimata; Toru Inami; Nobuaki Kobayashi; Ryo Munakata; Daisuke Murakami; Shigenobu Inami; Kentaro Okamatsu; Takayoshi Ohba; Chikao Ibuki; Noritake Hata; Yoshihiko Seino; Kyoichi Mizuno
OBJECTIVE To determine if prediabetes is associated with atherosclerosis of coronary arteries, we evaluated the degree of coronary atherosclerosis in nondiabetic, prediabetic, and diabetic patients by using coronary angioscopy to identify plaque vulnerability based on yellow color intensity. RESEARCH DESIGN AND METHODS Sixty-seven patients with coronary artery disease (CAD) underwent angioscopic observation of multiple main-trunk coronary arteries. According to the American Diabetes Association guidelines, patients were divided into nondiabetic (n = 16), prediabetic (n = 28), and diabetic (n = 23) groups. Plaque color grade was defined as 1 (light yellow), 2 (yellow), or 3 (intense yellow) based on angioscopic findings. The number of yellow plaques (NYPs) per vessel and maximum yellow grade (MYG) were compared among the groups. RESULTS Mean NYP and MYG differed significantly between the groups (P = 0.01 and P = 0.047, respectively). These indexes were higher in prediabetic than in nondiabetic patients (P = 0.02 and P = 0.04, respectively), but similar in prediabetic and diabetic patients (P = 0.44 and P = 0.21, respectively). Diabetes and prediabetes were independent predictors of multiple yellow plaques (NYPs ≥2) in multivariate logistic regression analysis (odds ratio [OR] 10.8 [95% CI 2.09–55.6], P = 0.005; and OR 4.13 [95% CI 1.01–17.0], P = 0.049, respectively). CONCLUSIONS Coronary atherosclerosis and plaque vulnerability were more advanced in prediabetic than in nondiabetic patients and comparable between prediabetic and diabetic patients. Slight or mild disorders in glucose metabolism, such as prediabetes, could be a risk factor for CAD, as is diabetes itself.
International Journal of Cardiology | 2013
Masamichi Takano; Daisuke Murakami; Masanori Yamamoto; Osamu Kurihara; Koji Murai; Toru Inami; Nakahisa Kimata; Takayoshi Ohba; Yoshihiko Seino; Kyoichi Mizuno
BACKGROUND Although several clinical trials have shown the superior efficacy and safety of second-generation everolimus-eluting stents (EES) in comparison with first-generation paclitaxel-eluting stents (PES), the differences in the vascular healing process between EES and PES in a human coronary artery during an early stage are unknown. METHODS A prospective optical coherence tomography (OCT) observation was performed for 25 EES in 21 patients and 27 PES in 21 patients at 6 months after implantation. Cross-sections within single-stent segments were analyzed at intervals of 1mm. The neointimal (NI) thickness on each strut was measured. Uncovered struts (NI thickness=0 μm), malapposed struts, NI area (%), uncovered strut ratio >0.3 (UCSR; number of uncovered struts/number of total struts) per cross-section, and in-stent thrombus were evaluated. RESULTS A total of 5198 EES struts in 514 cross-sections and 4243 PES struts in 469 cross-sections were identified. NI thickness and its area were smaller for EES than PES (80.0 ± 84.8 μm vs. 117.9 ± 140.0 μm and 19.1 ± 8.9% vs. 23.7 ± 11.5%, respectively; P<0.001). The frequencies of uncovered struts and malapposed struts were lower in EES compared to PES (2.3% vs. 5.2% and 2.1% vs. 5.7%, respectively; P<0.001). Patients who had cross-sections of UCSR >0.3 and thrombi were identified less frequently in EES than in PES group (5% vs. 57%; P<0.001, and 19% vs. 48%; P=0.05, respectively). CONCLUSIONS Six-month OCT examination showed a favorable vessel healing response after the implantation of EES, demonstrating less in-stent late loss as well as fewer uncovered struts and better stent apposition to the vessel wall in comparison with PES.
Circulation-cardiovascular Interventions | 2010
Masamichi Takano; Masanori Yamamoto; Masayuki Mizuno; Daisuke Murakami; Toru Inami; Nakahisa Kimata; Koji Murai; Nobuaki Kobayashi; Kentaro Okamatsu; Takayoshi Ohba; Yoshihiko Seino; Kyoichi Mizuno
Background—Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results—Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 &mgr;m versus 123.0±102.5 &mgr;m; P<0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P=0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P=1.0), the cross sections with ESL increased (9.6% versus 15.2%; P=0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P<0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P=1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions—The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.Background— Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results— Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 μm versus 123.0±102.5 μm; P <0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P =0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P =1.0), the cross sections with ESL increased (9.6% versus 15.2%; P =0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P <0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P =1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions— The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.
Journal of Cardiology | 2012
Toru Inami; Yoshihiko Seino; Toshiaki Otsuka; Masanori Yamamoto; Nakahisa Kimata; Daisuke Murakami; Masamichi Takano; Takayoshi Ohba; Chikao Ibuki; Kyoichi Mizuno
BACKGROUND Sleep disordered breathing (SDB) is highly prevalent in patients with cardiovascular disease, although it is not clear whether SDB has any link to coronary atherosclerotic burden in patients with stable coronary artery disease (CAD). This study sought to analyze the links between SDB, coronary atherosclerotic burden, and cardiac biomarkers in stable CAD patients. METHODS AND RESULTS We studied 83 consecutive patients who underwent coronary angiography or scheduled percutaneous coronary intervention. SDB was evaluated by an ambulatory polysomnographic monitoring device. Coronary atherosclerotic burden was evaluated by the Gensini score, and myocardial stress/injury were assessed by measuring plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high sensitivity troponin T (hs-TnT). Patients with an apnea hypopnea index (AHI)≧15 events/h (n=32) showed significantly higher Gensini score (35.7±38.0 vs 20.1±19.7, p=0.033) than those with AHI<15. The higher AHI group showed significantly higher NT-proBNP (275.8±402.6 pg/ml vs 131.9±146.3 pg/ml, p=0.047) and hs-TnT levels (0.011±0.005 ng/ml vs 0.008±0.003 ng/ml, p=0.015). Furthermore it was revealed that AHI significantly correlated with the Gensini score (r=0.253, p=0.036), NT-proBNP (r=0.266, p=0.027), and hs-TnT (r=0.274, p=0.023), and multiple stepwise linear regression analysis revealed that AHI (β=0.257, p=0.029) and history of smoking (β=0.244, p=0.038) were independently correlated with Gensini score among clinical and SDB-related parameters. CONCLUSIONS Severity of SDB has a significant link to the severity of coronary atherosclerotic burden, which also reflected elevated NT-proBNP and hs-TnT as silent myocardial ischemia and minute myocardial injury even in stable CAD patients.
Journal of Clinical Medicine Research | 2012
Chikao Ibuki; Yoshihiko Seino; Toshiaki Otsuka; Nakahisa Kimata; Toru Inami; Ryo Munakata; Kyoichi Mizuno
Background The aim of this study is to determine the prevalence of minute myocardial damage (MMD) in already statin-treated dyslipidemic patients with a low high-density lipoprotein-cholesterol (HDL-C) level, and to evaluate whether pitavastatin could affect the lipid profiles and biomarkers reflecting myocardial stress and injury. Methods Twenty patients (15 men; age 66 ± 8) being treated with any statin but who had HDL-C < 40 mg/dL, were switched to pitavastatin (2 mg/day) treatment. The patient lipid profiles and the levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitive troponin T (hsTnT), and high-sensitive C-reactive protein (hs-CRP) were evaluated for six months. Results At three months after the statin replacement, the HDL-C significantly increased from 37 ± 3 mg/dL to 40 ± 5 mg/dL (P < 0.05), and the low-density lipoprotein-cholesterol (LDL-C) and LDL-C/HDL-C ratio significantly reduced (100 ± 28 mg/dL to 86 ± 22 mg/dL, P < 0.05; 2.68 ± 0.67 to 2.17 ± 0.64, P < 0.05, respectively), and these changes were sustained for six months. In the whole study population, no significant changes were observed in the NT-proBNP, hsTnT, or hsCRP for six months. However, in 11 cases who showed a positive (> 0.003 ng/mL) hsTnT at baseline, a significant reduction in the hsTnT was observed (0.016 ± 0.020 ng/mL to 0.014 ± 0.020 ng/mL, P < 0.05), and its percent reduction significantly correlated with the percent increase in HDL-C (r = -0.68, P < 0.05). Conclusions MMD (positive hsTnT) was observed in more than half of patients with low HDL-C despite the administration of any statin, and the replacement of their previous statin with pitavastatin further improved their lipid profiles and led to better myocardial protection, possibly mediated via the elevation of the HDL-C level.
Circulation-cardiovascular Interventions | 2010
Masamichi Takano; Masanori Yamamoto; Masayuki Mizuno; Daisuke Murakami; Toru Inami; Nakahisa Kimata; Koji Murai; Nobuaki Kobayashi; Kentaro Okamatsu; Takayoshi Ohba; Yoshihiko Seino; Kyoichi Mizuno
Background—Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results—Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 &mgr;m versus 123.0±102.5 &mgr;m; P<0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P=0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P=1.0), the cross sections with ESL increased (9.6% versus 15.2%; P=0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P<0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P=1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions—The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.Background— Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results— Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 μm versus 123.0±102.5 μm; P <0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P =0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P =1.0), the cross sections with ESL increased (9.6% versus 15.2%; P =0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P <0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P =1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions— The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.
Journal of the American College of Cardiology | 2013
Toru Inami; Yoshihiko Seino; Nakahisa Kimata; Masanori Yamamoto; Kazunori Tomita; Akihiro Shirakabe; Ryo Munakata; Daisuke Murakami; Takuro Shinada; Masamichi Takano; Takayoshi Ohba; Chikao Ibuki; Noritake Hata; Kyoichi Mizuno
Background: Sleep Disordered Breathing (SDB) is known to be co-morbidity with cardiovascular diseases and has been linked to hypertension, which is a major risk factor for aortic dissection (AD). It was reported that SDB was related to the development of acute AD. However distinctive characteristics between convalescent phase of AD and stable coronary artery disease (CAD) have not been well known. The purpose of the present study is to investigate the differences in the impact of SDB to AD and CAD.
Journal of the American College of Cardiology | 2012
Osamu Kurihara; Masanori Yamamoto; Chikao Ibuki; Toru Inami; Nakahisa Kimata; Nobuaki Kobayashi; Kyoichi Mizuno; Ryo Munakata; Daisuke Murakami; Takayoshi Ohba; Yoshihiko Seino; Tetsurou Shimura; Masamichi Takano; Seiji Kano
Background: It remains unclear whether coronary plaque composition is associated with peri-procedural myocardial injury (PMI) after percutaneous coronary intervention (PCI). This study sought to determine the impact of plaque composition analysis by iMapTMintravascular ultrasound (iMap-IVUS) (Boston Scientific, Boston, MA), a recently developed intracoronary imaging system for tissue characterization, on PMI assessed using a highly sensitive assay for cardiac troponin T (hs-TnT). Methods: We examined 56 culprit plaques in patients with 52 stable and 4 unstable angina pectoris by iMap-IVUS. The major tissue characteristics at minimal lumen area site were classified by iMap-IVUS as fibrotic, lipidic, necrotic and calcified components, and these are described herein as relative plaque areas. The hs-TnT values were measured before and 24 hours after PCI, and differences were expressed as hs-TnT. High hs-TnT elevation was defined as hs-TnT level 0.037 pg/mL of median value. Patients were divided into 2 groups according to the presence (Group I, n 28) or absence (Group II, n 28) of high hs-TnT elevation. Results: Compared with Group II, Group I had significantly higher percent necrotic area (45 12 vs. 35 18%, p 0.012) and lower percent fibrotic area (42 12 vs. 53 20%, p 0.016). The percent lipidic and calcified areas were similar between the two groups. Group I also had longer lesion length (17.9 9.9 vs. 13.0 4.9 mm, p 0.024), a lower frequency of direct stenting (18 vs. 54%, p 0.011), and a higher frequency of post-dilation (89 vs. 61%, p 0.014) than Group II. The hs-TnT level correlated positively with percent necrotic area (r 0.40, p 0.003), lesion length (r 0.31, p 0.021), and negatively with percent fibrotic area (r -0.35, p 0.008). In multivariate logistic regression analysis, a larger percent necrotic area (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.02 1.14; p 0.005) and less direct stenting (OR, 0.11; 95%CI, 0.025 0.51; p 0.005) were independent predictors of high hs-TnT elevation. Conclusions: Plaque composition analysis by iMap-IVUS is useful to predict the elevation of hs-TnT after PCI.
Circulation-cardiovascular Interventions | 2010
Masamichi Takano; Masanori Yamamoto; Masayuki Mizuno; Daisuke Murakami; Toru Inami; Nakahisa Kimata; Koji Murai; Nobuaki Kobayashi; Kentaro Okamatsu; Takayoshi Ohba; Yoshihiko Seino; Kyoichi Mizuno
Background—Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results—Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 &mgr;m versus 123.0±102.5 &mgr;m; P<0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P=0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P=1.0), the cross sections with ESL increased (9.6% versus 15.2%; P=0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P<0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P=1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions—The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.Background— Late vascular responses after implantation of drug-eluting stents may play a key role in steadily increasing occurrence of very late stent thrombosis have not yet been fully investigated in human beings. Methods and Results— Serial optical coherence tomography observations at 2 and 4 years were collected for 17 patients treated with 21 sirolimus-eluting stents. Corresponding 376 cross sections within single-stent segments at intervals of 1 mm were selected for analyses, and neointimal thickness on each strut was measured. Extrastent lumen (ESL) was defined as an external lumen of the stent. Area and angle of ESL were measured. A total of 3369 and 3221 struts were identified at 2 and 4 years, respectively. From 2 to 4 years, mean neointimal thickness increased (76.8±75.6 μm versus 123.0±102.5 μm; P <0.0001), whereas frequency of patients with uncovered struts decreased (88% versus 29%; P =0.002). Although prevalence of patients that had ESL was similar (59% of 2 years versus 65% of 4 years; P =1.0), the cross sections with ESL increased (9.6% versus 15.2%; P =0.02). Moreover, area and angle of ESL increased from 2 to 4 years (0.28±0.27 mm2 versus 0.62±0.68 mm2 and 16.6±5.4° versus 65.1±38.4°; P <0.01, respectively). The incidence of subclinical thrombus did not decrease (24% at 2 years versus 29% at 4 years; P =1.0). All thrombi were identified in patients who had cross sections with ESL. Conclusions— The current serial optical coherence tomography study showed an augmentation of neointimal growth at the late phase of sirolimus-eluting stent implantation. ESL may contribute to thrombus formation and ESL of sirolimus-eluting stents expanded from 2 to 4 years.