Impact of stent strut link location in proximal balloon edge dilation technique for bifurcation percutaneous coronary intervention.

The single-stent strategy has generally been accepted as the default approach to bifurcation percutaneous coronary intervention. We have proposed the proximal balloon edge dilation (PBED) technique to prevent stent deformation during side branch (SB) dilation. This bench study aimed to evaluate the impact of stent link location and stent design on stent deformation, obstruction by stent struts at a jailed SB ostium, and incomplete stent apposition in the proximal optimization technique (POT)-PBED procedure. A coronary bifurcation model was used. We intentionally set the absence or presence of stent link on the carina (link-free or link-connect) under videoscope observation and compared stent parameters between 3- and 2-link stents (n = 5 each, n = 20 total). In the link-free group, the SB jailing rate of 3-link stents was significantly higher than that of 2-link stents (15.5 ± 5.1% vs. 6.6 ± 1.2%, p = 0.009). In the link-connect group, the SB jailing rate of 3-link stents was significantly lower than that of 2-link stents (30.0 ± 4.5% vs. 39.0 ± 2.6%, p = 0.009). In the bifurcation segment, the rate of incomplete stent apposition was significantly lower for 3-link stents of the link-connect group than for 2-link stents of the link-connect group (3.3 ± 4.2% vs. 19.0 ± 7.8%, p = 0.009). For both stent designs, ellipticity ratio was higher for link-connect group than link-free group. Link location as well as stent cell design greatly impacted stent deformation during the POT-PBED procedure.

Efficacy of Optical Coherence Tomography-Guided Primary Percutaneous Coronary Intervention in Patients with Acute Coronary Syndrome.

Background: Optical coherence tomography (OCT) is currently used as a guide for percutaneous coronary intervention (PCI), however its clinical benefit in comparison with intravascular ultrasound (IVUS) remains unclear in patients with acute coronary syndrome (ACS). Objectives: The purpose of this study was to evaluate the clinical efficacy of OCT-guided PCI in comparison with IVUS-guided PCI in patients with ACS. Methods: The study participants comprised 280 consecutive ACS patients who underwent primary PCI for de novo culprit lesions under OCT or IVUS guidance. Results: Compared with the IVUS-guided group, the OCT-guided group had lower Killip classification (p < 0.001) and lower creatinine level at baseline (0.80 ± 0.37 mg/dl vs. 1.13 ± 1.29 mg/dl, p = 0.004). Fluoroscopy time and total procedure time were significantly shorter in the OCT-guided group than in the IVUS-guided group (32 ± 13 min vs. 41 ± 19 min, p < 0.001, and 98 ± 39 min vs. 127 ± 47 min, p = 0.002, respectively). The major adverse cardiovascular event-free survival curves were similar between the OCT- and IVUS-guided groups after adjusting for clinical background using propensity score (log-rank p = 0.328). Conclusions: After adjusting for clinical background, OCT-guided PCI could provide comparable clinical outcomes to IVUS-guided PCI in patients with ACS. Shorter fluoroscopy time and total procedure time with OCT may reduce patient radiation exposure and also improve hospital workflow.

Efficacy of a new generation intracoronary optical coherence tomography imaging system with fast pullback.

OBJECTIVES: We sought to investigate whether a novel, fast-pullback, high-frequency optical coherence tomography (HF-OCT) imaging system enables data acquisition with a reduced amount of contrast agents while retaining the same qualitative and quantitative lesion assessment to conventional OCT. BACKGROUND: The increased amount of administered contrast agents is a major concern when performing intracoronary OCT. METHODS: The present study is a single-center, prospective, observational study including 10 patients with stable coronary artery disease. A total of 28 individual coronary arteries were assessed by both fast-pullback HF-OCT and by conventional OCT. RESULTS: The contrast volume used in each OCT run for the HF-OCT system was significantly lower than for the conventional OCT system (5.0 ± 0.0 mL vs. 7.8 ± 0.7 mL, respectively, with a mean difference of -2.84 [95% confidence interval [CI]: -3.10 to -2.58]). No significant difference was found in the median value of the clear image length between the two OCT systems (74 mm [interquartile range [IQR]; 63, 81], 74 mm [IQR; 71, 75], p = 0.89). Fast-pullback HF-OCT showed comparable measurements to conventional OCT, including minimum lumen area (3.27 ± 1.53 mm2 vs. 3.21 ± 1.53 mm2 , p = 0.27), proximal reference area (7.03 ± 2.28 mm2 vs. 7.03 ± 2.34 mm2 , p = 0.96), and distal reference area (5.93 ± 1.96 mm2 vs. 6.03 ± 2.02 mm2 , p = 0.23). Qualitative OCT findings were comparable between the fast-pullback HF-OCT runs and conventional OCT with respect to identifying lipid-rich plaques, calcifications, layered plaques, macrophages, and cholesterol crystals. CONCLUSION: With the fast pullback function of a novel HF-OCT imaging system, we acquired OCT images using a significantly lower amount of contrast volume while retaining a comparable qualitative and quantitative lesion assessment to conventional OCT.

Layered Plaque in Organic Lesions in Patients With Coronary Artery Spasm.

Background Coronary artery spasm plays a vital role in the pathogenesis of coronary plaques. We sought to investigate the plaque characteristics of co-existing organic lesions in patients with coronary artery spasm in comparison to those without coronary artery spasm by intracoronary optical coherence tomography (OCT). Methods and Results We included 39 patients who presented with a symptom suspected of coronary spastic angina and had an organic lesion, defined as ≥plaque burden of 50% assessed by OCT. Coronary artery spasm was diagnosed by positive acetylcholine provocation test, or by spontaneous spasm detected during coronary angiography. A total of 51 vessels with an organic lesion were identified. Of these, coronary artery spasm was observed in 30 vessels (spasm), while not in 21 vessels (non-spasm). Organic lesions in the spasm vessels, compared with those in the non-spasm vessels, had a higher prevalence of layered plaque (93% versus 38%, P<0.001), macrophages (80% versus 43%, P=0.016), and intraplaque microchannels (73% versus 24%, P<0.001), and lower prevalence of macrocalcification (23% versus 62%, P=0.009) as assessed by OCT. Conclusions Layered plaque, macrophages, and intraplaque microchannels, were frequently observed in organic lesions in patients with coronary artery spasm. These findings suggest that coronary artery spasm induces local thrombus formation as well as active inflammatory response, therefore increasing the risk of rapid plaque progression and ischemic events in patients with coronary artery spasm.

Bifurcation percutaneous coronary intervention of left main trunk treated using a proximal optimizing technique and proximal balloon edge dilation technique.

We present a case of bifurcation percutaneous coronary intervention (PCI) of the left main trunk (LMT) using a proximal balloon edge dilation (PBED) technique following a proximal optimizing technique (POT). The procedure of the PBED technique entailed precise positioning of the balloon for SB dilation, with the proximal radiopaque marker lying in the cross-sectional plane of the stent struts at the left circumflex artery (LCx) ostium. The PBED technique might prevent stent deformation induced by side branch (SB) dilation and eliminates the need for the second POT procedure in the re-POT sequence. In fact, three-dimensional reconstruction of optical coherence tomography (3D-OCT) revealed good opening of stent cells overlying the LCx ostium without deformation of stent struts causing incomplete stent apposition at the site opposite the LCx, so the second POT procedure was unnecessary in this case. .

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.

Impact of Coronary Stent Design in Proximal Balloon Edge Dilation Technique for Bifurcation Percutaneous Coronary Intervention.

The proximal optimizing technique (POT) -proximal balloon edge dilation (PBED) sequence for side branch (SB) dilatation with cross-over single-stent implantation decreases both strut obstruction at the SB ostium and stent deformation at the main branch (MB).The purpose of this experimental bench test was to assess the impact of stent design on stent deformation, obstruction by stent struts at a jailed SB ostium, and stent strut malapposition in the POT-PBED sequence.Fractal coronary bifurcation bench models (60- and 80-degree angles) were used, and crossover single-stent implantation (3-link stent: XIENCE Sierra, Abbott Vascular, Santa Clara, CA, n = 10; 2-link stent: Synergy, Boston Scientific, Marlborough, MA, n = 10) was performed from the MB using the POT-PBED sequence. Jailing rates at the SB ostium, stent deformation, and stent strut malapposition of the bifurcation segment were assessed using videoscopy and optical coherence tomography.After SB dilatation using the PBED technique, jailing rates at the SB ostium and stent deformation did not differ significantly between the two types of stents. Conversely, the rate of malapposed struts of the bifurcation segment after the PBED procedure was significantly lower with 3-link stents than with 2-link stents for both 60- and 80-degree angles (60-degree angle: 4.3% ± 4.4% versus 22.0% ± 11.1%, P = 0.044; 80-degree angle: 20.8% ± 15.1% versus 57.2% ± 17.0%, P < 0.001, respectively).In the POT-PBED sequence, 3-link stents might be a preferable coronary bifurcation stent, maintaining a jailed SB ostium while significantly reducing stent strut malapposition of the bifurcation segment when compared with 2-link stents.

Effect of proximal balloon edge dilation technique for opening a side branch ostium in repetitive-proximal optimizing technique sequence.

OBJECTIVE: The purpose of this experimental bench test was to compare stent deformation, obstruction of stent struts at a jailed side branch (SB) ostium, and stent strut malapposition between SB inflation using proximal balloon edge dilation (PBED) technique and SB inflation using conventional balloon dilation in repetitive-proximal optimizing technique (re-POT) sequence. BACKGROUND: The second proximal optimizing technique (POT) procedure in the re-POT sequence might increase obstruction of stent struts at a jailed SB ostium, because deformation of stent cells at the main branch (MB) occurred during SB inflation for opening the SB ostium. METHODS: A fractal coronary bifurcation bench model made of flexible urethane was used, and crossover single-stent implantation (Xience Sierra, Abbott Vascular, Santa Clara, CA, n = 12) was performed from the MB with the re-POT sequence. During the re-POT sequence, the jailing rate at the SB ostium assessed by videoscopy was compared between SB inflation using PBED technique (PBED group, n = 6) and SB inflation using conventional balloon dilation (conventional group, n = 6). RESULTS: The jailing rate after the second POT procedure tended to be lower in the PBED group than in the conventional group (26 ± 12% vs. 34 ± 8%, p = .211), and the change in the jailing rate during the second POT procedure was significantly smaller in the PBED group than in the conventional group (4.8 ± 5.3% vs. 11.6 ± 3.5%, p = .026). CONCLUSIONS: In the re-POT sequence, the PBED technique with a short balloon for SB inflation might minimize worsening of the jailing rate at the SB ostium during the second POT procedure.

Prevalence and Clinical Significance of Layered Plaque in Patients With Stable Angina Pectoris　- Evaluation With Histopathology and Optical Coherence Tomography.

BACKGROUND: Healed plaques are identified as a layered pattern with optical coherence tomography (OCT) imaging, but the exact relationship between healed plaques and the development of significant coronary stenosis in stable angina pectoris (SAP) is not fully understood.Methods and Results:A retrospective clinincal study investigated the OCT characteristics of culprit lesions of SAP patients (n=205), and a prospective study examined the histopathological characteristics of layered plaque in directional coronary atherectomy (DCA) samples (42 samples from 18 SAP patients). In the retrospective study, layered plaque was observed in 36.6% of the SAP culprit lesions. Compared with patients with non-layered plaque, male sex and smoking were more frequent, and HbA1c level was significantly higher in the patients with layered plaque (81.3% vs. 65.9%, P<0.05; 62.7% vs. 41.8%, P<0.05; 6.6±1.3% vs. 6.2±1.0%, P<0.05, respectively). Furthermore, layered plaque was accompanied by higher plaque vulnerability and smaller minimal lumen area. In the histopathological study, the layered plaques had a significantly higher rate of intramural thrombus and macrophages infiltration than non-layered plaques (75.0% vs. 14.3%, P<0.05; 75.0% vs. 38.1%, P<0.05, respectively). CONCLUSIONS: Healed plaque containing intramural thrombus is identified as layered plaque by OCT, and was frequently observed, even in SAP patients. Intramural thrombus might play an important role in the development of coronary plaque with a high degree of stenosis in SAP patients.

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.

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.

Multiple Unfavorable Echocardiographic Findings in Takotsubo Cardiomyopathy Are Associated with Increased In-Hospital Events and Mortality.

BACKGROUND: Various unfavorable echocardiographic findings other than apical ballooning, such as right ventricular involvement, mitral regurgitation, left ventricular outflow tract obstruction, and left ventricular thrombus, occur in takotsubo cardiomyopathy. Occasionally, these findings are observed simultaneously in a single patient. This study was performed to investigate the prevalence and characteristics of patients with multiple unfavorable echocardiographic findings in takotsubo cardiomyopathy and their associations with adverse outcomes. METHODS: The echocardiographic images of 113 patients with takotsubo cardiomyopathy (mean age, 72.7 ± 11.4 years; 29 men) were retrospectively reviewed. According to the number of unfavorable echocardiographic findings, patients were classified into a low-risk group (zero or one finding), an intermediate-risk group (two findings), and a high-risk group (three or more findings). In-hospital events were defined as a composite of acute heart failure, shock, ventricular tachyarrhythmia, and in-hospital death. RESULTS: Apical ballooning, right ventricular involvement, mitral regurgitation, left ventricular outflow tract obstruction, and left ventricular thrombus were observed in 92 (81.4%), 21 (18.6%), 17 (15.0%), 11 (9.7%), and three (2.7%) patients, respectively. There were 77 (68.1%), 25 (22.1%), and 11 (9.7%) patients in the low-, intermediate-, and high-risk groups, respectively. Logistic regression analysis indicated that being in the high-risk group had a significant association with in-hospital events (odds ratio, 8.74, P = .003) and death (odds ratio, 16.9; P = .027) compared with being in the low-risk group. Net reclassification improvement indicated that adding this risk group classification to known clinical factors that are associated with adverse outcomes could yield incremental information regarding patients with takotsubo cardiomyopathy with in-hospital events (net reclassification improvement, 0.59; P = .002). CONCLUSIONS: Multiple unfavorable echocardiographic findings in takotsubo cardiomyopathy are not uncommon and are associated with increased in-hospital events and mortality.

Detection of Plaque Neovascularization by Optical Coherence Tomography: Ex Vivo Feasibility Study and In Vivo Observation in Patients With Angina Pectoris.

OBJECTIVES: The purposes of this study were: (1) to assess the feasibility of optical coherence tomography (OCT) for detecting neovascularization; and (2) to clarify the impact of plaque neovascularization on coronary vessel behavior over time. BACKGROUND: Plaque neovascularization may be related to plaque vulnerability. METHODS: In an ex vivo study, a total of 55 coronary plaques from 31 human cadavers were examined by OCT. Plaque neovascularization was diagnosed based on the presence or absence of microchannels (MCs) by OCT. In an in vivo study, we explored 83 major coronary arteries from 42 patients with angina pectoris. A total of 56 coronary plaques were selected from non-culprit (non-stented) lesions with plaque burden >40% by intravascular ultrasound (IVUS). These plaques were classified into two groups based on the presence or absence of MC by OCT. RESULTS: In the ex vivo study, the sensitivity and specificity of OCT to detect plaque neovascularization were 52% and 68%, respectively. In the in vivo study, MC was detected in 25 plaques (44.6%). High-density lipoprotein cholesterol was significantly lower in the MC group vs the non-MC group (42.7 ± 7.8 mg/dL vs 51.6 ± 14.4 mg/dL; P=.02). Percent change in lumen volume index (VI) in the MC group was significantly greater vs the non-MC group (P=.01). Percent change in lumen VI correlated significantly with percent change in external elastic membrane VI (P=.01). CONCLUSIONS: OCT was feasible for detecting neovascularization of coronary plaques. Serial OCT examinations revealed that coronary plaques with neovascularization showed greater luminal narrowing as a result of inadequate adaptive vessel remodeling.