Influence of dual antiplatelet therapy duration on neointimal condition after second-generation drug-eluting stent implantation.

Guidelines recommend shorter duration (1-12 months) for dual antiplatelet therapy (DAPT) in the second-generation drug-eluting stent (DES) era. However, whether shorter DAPT duration affects stent strut conditions and neointimal characteristics at mid-term follow-up remains uncertain. Therefore, we studied the relation between DAPT duration and vascular healing response as assessed by optical coherence tomography (OCT). This study was retrospective observational study. Participants comprised 64 patients who underwent serial OCT at both 9 and 18 months after DES implantation. All patients received DAPT until the 9-month follow-up then were divided into two groups: 49 patients who continued DAPT (longer DAPT group); and 15 patients who stopped taking the P2Y12 inhibitor and were treated with aspirin alone (shorter DAPT group) at the 18-month follow-up. Using OCT, we evaluated and compared stent strut conditions and neointimal characteristics between groups at both 9 and 18 months after stent implantation. Baseline clinical and procedural parameters were mostly similar between groups. At the 18-month follow-up, no in-stent thrombus assessed by OCT was observed in either group. No significant differences in OCT characteristics or measurements of neointima were seen between groups at 9- or 18-month follow-ups. Neointimal volume increased from 9 to 18 months in both groups, with a similar degree of neointimal proliferation in both groups (shorter DAPT group, 0.23 ± 0.29 mm3/mm; longer DAPT group, 0.19 ± 0.27 mm3/mm; P = 0.56). In conclusion, interrupting DAPT 9 months after second-generation DES implantation did not affect the development of in-stent thrombus, neointimal proliferation or stent strut coverage at 18-month follow-up compared with continuing DAPT.

Immunoglobulin G4-related masses surrounding coronary arteries: a case report.

BACKGROUND: Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition with high serum IgG4 levels affecting various organs, such as the pancreas, lacrimal and salivary glands, thyroid, kidney, and lung. Typical cardiovascular manifestations of IgG4-RD include periaortitis, coronary arteritis, and pericarditis. However, reports of IgG4-RD associated with coronary arteritis are rare. Here, we report a case of IgG4-related masses surrounding the coronary arteries. CASE SUMMARY: A 59-year-old man was referred to our hospital because of mediastinal masses detected by computed tomography (CT). Coronary CT angiography revealed masses surrounding the right coronary artery and the left anterior descending coronary artery. An elevated serum level of IgG4 and histological findings led to the diagnosis of IgG4-related coronary arteritis with mass formation. Coronary angiography showed numerous feeding arteries to the masses, which were demonstrated as multiple microchannels in the intravascular ultrasound (IVUS) images. DISCUSSION: IgG4-RD involving the cardiovascular system has been reported. However, coronary artery disease associated with IgG4-RD is very rare, and the mechanism of mass formation in IgG4-related coronary arteritis is unclear. In our case, within the cardiovascular system, IgG4-RD was limited to the coronary arteries, suggesting that the affected coronary arteries may provide the necessary blood supply to the mass, thus, aiding its growth. These findings were supported by the images from coronary angiography and IVUS.

Coronary bifurcation bench test using multimodality imaging: Impact of stent strut link location on stent deformity and jailed side-branch orifices during re-proximal optimizing technique.

OBJECTIVES: The purpose of this study was to compare the stent deformation, obstruction of stent struts at a jailed side branch (SB) ostium, and stent strut malapposition after a repetitive proximal optimizing technique (re-POT) sequence between bifurcation lesions with and without stent links at SB ostia in ex vivo experimental setting. METHODS: A flexible urethane coronary bifurcation bench model was used, and crossover single stent implantation was performed from main branch (MB) with re-POT sequence. Under videoscope observation, presence (link group, n = 12) or absence (no-link group, n = 12) of stent link at distal semicircle of SB ostium was intentionally set, and rewiring was performed through distal cell in four different stent platforms. RESULTS: There were no significant differences in the rate of malapposed struts and in SB jailing ratio after the re-POT sequence between the link and no-link groups. SB jailing ratio increased significantly from 8.0% to 9.6% during the second POT procedure (P < 0.001). SB jailing ratio after the second POT procedure differed among stent platforms. CONCLUSIONS: The presence of a stent link at an SB ostium was not associated with a rate of malapposed struts and SB jailing ratio after the re-POT sequence. SB jailing ratio was significantly increased after second POT procedure, but was different among stent platforms. The Xience stent might minimize the change of SB jailing ratio and be suitable for coronary bifurcation stenting using re-POT sequence.

Vascular Healing Response after Everolimus-Eluting Stent Implantation in Acute Coronary Syndrome Culprit Lesions: Comparison with Implantation in Stable Angina Pectoris.

BACKGROUND: To evaluate the neointimal conditions of everolimus-eluting stents (EESs) implanted in culprit lesions of patients with acute coronary syndrome (ACS) compared with stable angina pectoris (SAP) using optical coherence tomography (OCT). EESs are second-generation drug-eluting stents that have recently been shown to be useful in patients with ACS as well as in patients with SAP. However, few studies have analyzed the intra-stent conditions of EESs that can lead to favorable results in such ACS lesions. METHODS: We evaluated 41 ACS patients with EES implantation (age, 66.7 ± 10.3 years) and 59 SAP patients enrolled as controls (age, 68.3 ± 10.7 years). OCT examinations were performed after 9 months of follow-up after stent implantation, and the condition of the neointimal coverage over every stent strut was assessed in 1-mm intervals. In addition, neointimal thickness (NIT) over each strut was measured and tissue characteristics were examined. RESULTS: There was no significant difference in mean NIT between the ACS (90.8 ± 88.2 mm) and SAP (87.3 ± 74.2 mm, p = 0.11) group. The rate of uncovered struts was significantly lower in the ACS group (11.5%) than in the SAP group (12.5%, p = 0.03). Neointimal tissue characteristics were also similar between groups. CONCLUSIONS: Vascular responses after EES implantation differed significantly between ACS and SAP lesions using OCT. However, these differences were considered small in clinical terms. Our OCT data support the favorable results of patients with EES implantation at mid-term follow-up, even in those with ACS.

Neointimal coverage of jailed side branches in coronary bifurcation lesions: an optical coherence tomography analysis.

OBJECTIVES: The jailed strut at the side-branch (SB) orifice may be a cause of delayed neointimal coverage and SB flow disturbance after single stenting to bifurcation. The aim of this study was to characterize the exact relationship between the jailed strut pattern at the SB orifice immediately after stent implantation and neointimal coverage of the jailed SB orifice in the chronic phase. PATIENTS AND METHODS: A total of 29 bifurcation (left anterior descending coronary artery and diagonal branch) lesions treated by optical coherence tomography-guide single-stent implantation and followed at 18 months after a percutaneous coronary intervention were included in this study. RESULTS: Using three-dimensional optical coherence tomography images, the jailed stent strut pattern was classified into two groups on the basis of the presence of a stent strut link at the SB orifice (link group: n=11, and no-link group: n=18). SB orifice obstruction by neointima was significantly greater in the link group than in the no-link group during the 18-month follow-up period (26.8±21.9 vs. 9.5±22.1%, P=0.049). CONCLUSION: This single-center observational study with a small sample size showed that a jailed strut pattern at the SB orifice might be related to neointimal coverage of the SB orifice in bifurcation lesions treated with single-stent implantation. Further large-scale studies with long-term follow-up will be necessary to determine the exact relationship between the jailed strut pattern at the SB orifice and SB flow disturbance because of delayed neointimal coverage as well as clinical outcome.

Acute Coronary Syndrome Demonstrating Plaque Rupture in Calcified Lesions Visualized by Optical Frequency Domain Imaging.

A 68-year-old female with acute coronary syndrome was transferred to our hospital. Emergency coronary angiography showed 90% stenosis with severe calcification in the proximal right coronary artery (RCA). Intravascular ultrasound (IVUS) images were obtained and showed circumferential heavy calcification without any evidence of plaque rupture. Optical frequency domain imaging (OFDI) images were obtained in the RCA lesion 3 days after the initial coronary angiography. A cavity of plaque rupture in the calcified plaque by using OFDI was observed in the lesion, which could not be recognized by IVUS. Necrotic tissue was observed frequently in heavy calcified lesions and was usually hidden behind calcification. Judging from the OFDI images in this case, the thin fibrous cap over the necrotic tissue even if surrounded by calcification was disrupted and might have caused the acute coronary syndrome. However, necrotic tissue surrounded by calcification is generally recognized as calcified plaque in OFDI images because discrimination between necrotic tissue and calcification is based on the border characteristics (low intensity with diffuse border: necrotic tissue, low intensity with sharp border: calcification). Superficial residual necrotic tissue not yet replaced completely by calcification might cause plaque rupture and thus, result in acute coronary syndrome. In fact, there is a variety of OFDI and optical coherence tomography (OCT) characteristics in calcified plaque, such as relatively high intensity without attenuation or very low intensity with attenuation. Residual necrotic tissue within calcification could pose a problem in OCT/OFDI plaque evaluation.

In vivo assessment of vasa vasorum neovascularization using intravascular ultrasound: A comparison between acute coronary syndrome and stable angina pectoris.

BACKGROUND: Previous studies have suggested that vasa vasorum (VV) neovascularization plays an important role in the progression and vulnerability of coronary atherosclerotic plaque. METHODS: A total of 130 patients with coronary artery disease including 75 acute coronary syndrome (ACS) cases and 55 stable angina pectoris (SAP) cases were studied. By using intravascular ultrasound (IVUS), VV was defined as a small (<1mm) tubular or vesicular, low-echoic structure observed exterior to the media. Prevalence and maximal number of VV were compared between patients with ACS versus SAP. RESULTS: The prevalence of VV at the culprit lesion was similar between the 2 groups (97% vs. 93%, p=0.216). On the other hand, it was significantly higher in ACS than SAP at both reference sites (proximal: 93% vs. 81%, p=0.047 and distal: 88% vs. 60%, p<0.001, respectively). The maximum number of VV was significantly higher in ACS than in SAP (at the culprit lesion: 2.8±1.3 vs. 1.8±1.0, p<0.001, at the proximal reference: 1.9±1.1 vs. 1.3±0.9, p=0.003 and distal reference: 1.7±1.1 vs. 1.1±1.1, p=0.003, respectively). CONCLUSIONS: VV neovascularization of coronary arteries was more enhanced in patients with ACS than in those with SAP, supporting its relation to plaque vulnerability. VV detected by widely used IVUS could be an adequate surrogate marker for plaque vulnerability in vivo.

Optical Coherence Tomography Findings in Early Stent Thrombosis by Heparin-Induced Thrombocytopenia.

A 62-year-old man with a family history of coronary artery disease and a history of smoking, diabetes and dyslipidemia was admitted to our hospital with chest pain from acute myocardial infarction. Emergent coronary angiography was performed with intervention to a mid-right coronary occlusion with drug-eluting stent implantation. Optical coherence tomography (OCT) visualized well-apposed stent struts and no remarkable tissue protrusion, stent underexpansion, malapposition, edge dissection, and hematoma. Immediately after OCT imaging, a coronary angiogram showed a filling defect surrounded by contrast medium at the site of the stented lesion. OCT imaging was performed again and a low backscattering protrusion suggestive of white thrombus in the coronary lumen was clearly visualized in OCT imaging. We performed thrombus aspiration immediately after OCT imaging. Aspirated thrombi were off-white in color. We made a diagnosis of early-onset heparin-induced-thrombocytopenia (HIT) due to thrombus formation within the stent and positive HIT antibodies. OCT in the acute phase of stent thrombosis allowed us to promptly identify the main causative mechanisms of early stent thrombosis.

Impact of branching angle on neointimal coverage of drug-eluting stents implanted in bifurcation lesions.

OBJECTIVES: To investigate the impact of branching angle (BA) on neointimal coverage of drug-eluting stents (DESs) in bifurcation lesions. BACKGROUND: Previous experimental studies indicated that BA influences the local flow turbulence and wall shear stress, which are associated with neointimal coverage of DESs. METHODS: Fifty-five bifurcation lesions in 47 patients were evaluated by serial optical coherence tomography (OCT) before DES implantation and at follow-up. Neointimal coverage was assessed in cross-sectional OCT images containing the side branch; regions including the side branch ostium (SO) and vessel wall (VW) were assessed separately. BA was measured using angiography (Angio-BA) and longitudinal OCT imaging (OCT-BA). RESULTS: In the SO region, a significant negative correlation was found between the uncovered strut percentage and Angio-BA or OCT-BA (r=-0.41, P=0.0024; r=-0.33, P=0.0167, respectively) and a significant positive correlation was found between Angio-BA and average neointimal thickness (r=0.31, P=0.025), whereas no correlation was observed between OCT-BA and average neointimal thickness (r=0.20, P=0.158). In the VW region, no correlation was found between Angio-BA or OCT-BA and the uncovered strut percentage or average neointimal thickness. CONCLUSION: BA influence the neointimal coverage over DES struts in the SO at coronary bifurcation lesions, but not in those attached to the VW.

Thin-cap fibroatheroma and large calcification at the proximal stent edge correlate with a high proportion of uncovered stent struts in the chronic phase.

OBJECTIVE: A high proportion of uncovered stent struts is associated with late stent thrombosis after drug-eluting stent (DES) implantation, which frequently results in myocardial infarction or death. However, the predictors of uncovered stent struts remain unknown. Here, using optical coherence tomography (OCT), we studied the baseline tissue characteristics of the target coronary segment and evaluated their influence on the neointimal coverage of the strut in the chronic phase. METHODS: We analyzed 118 coronary lesions treated with OCT-guided DES implantation. OCT examinations of target lesions were performed before and after DES implantation, and tissue characteristics were evaluated within 5 mm outer segment of both stent edges. At follow-up, stent strut coverage was assessed within 5 mm inner segment from each stent edge. On the basis of the proportion of uncovered stent struts in the chronic phase, target segments were divided into poorly covered (the highest quartile with % uncovered struts, n=29) and well-covered (the remaining lower quartiles with % uncovered struts, n=89) groups. RESULTS: Clinical parameters were similar between the two groups. On baseline OCT images, thin-cap fibroatheroma (TCFA) and large calcification were more frequently observed in the poorly covered group than the well-covered group (10.3 vs. 0.0%, P=0.0032, and 27.6 vs. 9.0%, P=0.017, respectively). Furthermore, multivariable analysis showed TCFA and large calcification at the proximal edge, but not at the distal edge, were predictors of uncover stent struts. CONCLUSION: TCFA and large calcification at the proximal stent edge are strong predictors of uncovered stent struts. OCT is useful for selecting stent landing sites in terms of future occurrence of uncovered stent struts.

Changes in the reference lumen size of target lesions before and after coronary stent implantation: Evaluation with frequency domain optical coherence tomography.

OBJECTIVE: In optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI), stent size is usually determined according to the pre-PCI lumen size of either the distal or proximal reference site. However, the effect of the OCT imaging catheter crossing the target lesion on the reference lumen measurements has not been studied. We evaluated changes in the reference lumen size before and after PCI using frequency domain OCT. METHODS: For 100 consecutive patients with PCI, mean lumen diameter (LD) and lumen area (LA) were measured at the proximal and distal reference sites before and after coronary stent implantation with OCT. RESULTS: Mean LD and LA of the distal reference site were significantly increased after PCI with stent implantation (2.57 ± 0.6 to 2.62 ± 0.64 mm, p < 0.01 and 5.20 ± 2.66 to 5.41 ± 2.54 mm2, p < 0.01, respectively). By contrast, these indices at the proximal reference site were significantly decreased. ROC curve analysis selected MLA of 1.50 mm2 as the best cutoff value for changes in mean LD. Distal mean LD was markedly increased after PCI in lesions with MLA < 1.50 mm (2.28 ± 0.48 to 2.40 ± 0.17 mm, P < 0.001), but did not change in lesions with MLA > 1.50 mm2. Tissue characteristics were not correlated with changes in reference lumen size. CONCLUSIONS: When we select the stent size during OCT-guided PCI, we need to pay attention to the decrease in the luminal measurement of the reference sites, especially in lesions with tight stenosis.