Prediction of Slow-Flow Phenomenon After Stent Implantation Using Near-Infrared Spectroscopy in Patients With Acute and Chronic Coronary Syndrome.

BACKGROUND: The slow-flow phenomenon is associated with worse clinical outcomes after percutaneous coronary intervention (PCI), so our goal for this study was to see how predictive how near-infrared spectroscopy (NIRS) could be.Methods and Results: We enrolled 179 lesions from 152 patients who had de novo coronary stent implantation guided by NIRS-intravascular ultrasound (IVUS) (male: 69.1%, mean age: 74.3±11.5 years, acute coronary syndrome: 65.1%, diabetes: 42.1%). NIRS automatically determined the maximum 4-mm lipid core burden index (maxLCBI4 mm) value at pre- and post-PCI procedures. The slow-flow phenomenon was defined as the deterioration of TIMI (Thrombolysis in Myocardial Infarction) flows on angiography during the PCI procedure in the absence of mechanical obstruction. The slow-flow phenomenon occurred in 13 (7.3%) lesions, and the slow-flow phenomenon group had a significantly higher maxLCBI4 mm(740±147 vs. 471±223, P<0.001). The best maxLCBI4 mmcutoff point in both acute and chronic coronary syndrome was 578 and 480, with sensitivity of 100%, for predicting the slow-flow phenomenon. In the receiver-operating characteristics analysis, the area under the curve for acute and chronic coronary syndrome was 0.849 and 0.851, respectively. CONCLUSIONS: The results of this study support the utility of NIRS-IVUS-guided PCI for the prediction of the slow-flow phenomenon.

Risk Factors for Vulnerable Plaque Detected Using Near-Infrared Spectroscopy in Patients Receiving Statin Therapy with No History of Coronary Artery Disease.

Residual risk of atherosclerosis remains high despite the use of lipid-lowering therapy with statins. Near-infrared spectroscopy intravascular ultrasound imaging (NIRS-IVUS) can identify vulnerable plaque via the detection of lipid-rich plaque. This study aimed to reveal the clinical characteristics of patients with vulnerable plaque despite statin therapy.NIRS-IVUS was used to determine the maximum 4 mm Lipid Core Burden Index (MaxLCBI4 mm) values of 38 de novo culprit lesions from 32 patients with acute coronary syndrome (53%) (mean age: 73.1 ± 13.1 years) who underwent percutaneous coronary intervention after a minimum 6 months of statin therapy for primary prevention. A patient with vulnerable plaque was defined as an individual presenting at least 1 target lesion with a vulnerable plaque (MaxLCBI4 mm > 400). Overall, the average low-density lipoprotein cholesterol (LDL-C) level was 95.5 ± 27.2 mg/dL. Patients in the vulnerable plaque group were younger and had higher LDL-C, triglycerides, and non-high-density lipoprotein cholesterol (HDL-C) levels than those in the non-vulnerable plaque group. The MaxLCBI4 mm was positively correlated with LDL-C (P = 0.0002), triglycerides (P = 0.0003), and non-HDL-C (P = 0.0001). In multivariate analysis, all 3 treatable lipid components failed to show an independent relationship with the patients with vulnerable plaque. Using receiver-operating characteristics curve analysis, the cutoff points for LDL-C, triglycerides, and non-HDL-C were determined to be 78 mg/dL, 108 mg/dL, and 111 mg/dL, respectively, at MaxLCBI4 mm > 400. In conclusion, this study supports a more comprehensive and aggressive lipid-lowering therapy for the primary prevention of coronary artery disease.

Relationship of quantitative flow ratio after second-generation drug-eluting stent implantation to clinical outcomes.

The correlation of fractional flow reserve, which is presently the gold standard for evaluating myocardial ischemia, with three-dimensional quantitative coronary analysis-based quantitative flow ratio (QFR) is well-known. This study aims to evaluate the relationship of QFR after second-generation drug-eluting stent (2nd gen-DES) implantation to clinical outcomes. A total of 61 consecutive lesions, on which 2nd gen-DES implantation was performed from October 2014 to December 2015, were analyzed. Contrast-flow QFR (c-QFR) was obtained using reliable software (QAngio XA 3D) by modeled hyperemic flow velocity derived from coronary angiography without pharmacologically induced hyperemia. Clinical and angiographic data at the follow-up (18-30 months) were obtained from all cases. c-QFR measurement was possible in 52 (85%) lesions. Of these, clinically-driven target vessel revascularization (TVR) was performed in 8 (15%) lesions. Vessel c-QFR was significantly lower in the TVR group (0.703 ± 0.163 vs. 0.883 ± 0.103, p = 0.016). In the results of the receiver operating characteristics analysis for TVR, area under the curve for vessel c-QFR was 0.857. The cutoff point for the prediction of TVR was defined as vessel c-QFR of ≤ 0.82, the sensitivity of 88%, and specificity of 80%. Conclusion: Vessel c-QFR can predict TVR after 2nd gen-DES implantation. Further investigation is warranted to evaluate whether c-QFR guided coronary intervention ameliorates TVR rate.

Quantitative optical coherence tomography analysis for late in-stent restenotic lesions.

Coronary optical coherence tomography (OCT) has the potential to identify in-stent neoatherosclerosis, which is a possible risk factor for late acute coronary events after drug-eluting stent implantation. The purpose of this study was to investigate differences between mid-term and late in-stent restenosis after stent implantation by quantitative and semiautomated tissue property analysis using OCT. In total, 1063 OCT image frames of 16 lesions in 15 patients were analyzed. This included 346 frames of 6 lesions in late in-stent restenosis, which was defined as restenosis that was not detected at 6 to 12 months but ≥ 12 months after follow-up coronary angiography. Signal attenuation was circumferentially analyzed using a dedicated semiautomated software. Attenuation was assessed along 200 lines delineated radially for analysis of the in-stent restenotic lesions (between the lumen and stent contours). All lines were anchored by the image wire to avoid artifacts resulting from wire location. Stronger signal attenuation at the frame level (2.46 ± 0.78 versus 1.47 ± 0.32, P < 0.001) and higher maximum signal intensity at the lesion level (9.19 ± 0.19 versus 8.84 ± 0.32, P = 0.018) were observed in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions. OCT demonstrated stronger signal attenuation and higher maximum signal intensity in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions, indicating the possibility of neoatherosclerosis.

Edge vascular response after polymer-free vs. polymer-based paclitaxel-eluting stent implantation.

BACKGROUND: It is unknown if lack of polymer can provoke a different edge response in drug-eluting stents. The aim of this study was to compare edge vascular response between polymer-free paclitaxel-eluting stent (PF-PES) and polymer-based paclitaxel-eluting stents (PB-PES). METHODS AND RESULTS: A total of 165 eligible patients undergoing percutaneous coronary intervention were prospectively randomized 1:1 to receive either PF-PES or PB-PES. Those patients with paired intravascular ultrasound (IVUS) after procedure and at 9-month follow-up were included in this analysis.Seventy-six patients with 84 lesions, divided into PB-PES (38 patients, 41 lesions) and PF-PES groups (38 patients, 43 lesions) had paired post-procedure and 9-month follow-up IVUS and were therefore included in this substudy. There was a significant lumen decrease at the proximal edge of PF-PES (from 9.02±3.06 mm(2)to 8.47±3.05 mm(2); P=0.040), and a significant plaque increase at the distal edges of PF-PES (from 4.39±2.73 mm(2)to 4.78±2.63 mm(2); P=0.004). At the distal edge there was a significant plaque increase in the PF-PES compared to PB-PES (+8.0% vs. -0.6%, respectively; P=0.015) with subsequent lumen reduction (-5.2% vs. +6.0%, respectively; P=0.024). CONCLUSIONS: PF-PES had significant plaque increase and lumen reduction at the distal edge as compared to PB-PES, probably due to difference in polymer-based drug-release kinetics between the 2 platforms.

One-year head to head comparison of the neointimal response between sirolimus eluting stent with reservoir technology and everolimus eluting stent: an optical coherence tomography study.

OBJECTIVE: to compare the vascular healing process between the sirolimus-eluting NEVO and the everolimus-eluting Xience stent by optical coherence tomography (OCT) at 1-year follow-up. BACKGROUND: Presence of durable polymer on a drug-eluting metallic stent may be the basis of an inflammatory reaction with abnormal healing response. The NEVO stent, having a bioresorbable polymer eluted by reservoir technology, may overcome this problem. METHODS: All consecutive patients, who received NEVO or Xience stent implantation between September 2010 and October 2010 in our institution, were included. Vascular healing was assessed at 1-year as percentage of uncovered struts, neointimal thickness (NIT), in-stent/stent area obstruction and pattern of neointima. RESULTS: A total 47 patients (2:1 randomization, n = 32 NEVO, n = 15 Xience) were included. Eighteen patients underwent angiographic follow-up (eight patients with nine lesions for NEVO vs. 10 patients with 11 lesions for Xience). The angiographic late loss was numerically higher but not statistically different in NEVO compared with Xience treated lesions (0.38 ± 0.47 mm vs. 0.18 ± 0.27 mm; P = 0.171). OCT analysis of 4,912 struts demonstrated similar rates of uncovered struts (0.5 vs. 0.7%, P = 0.462), higher mean NIT (177.76 ± 87.76 µm vs. 132.22 ± 30.91 µm; P = 0.170) and in stent/stent area obstruction (23.02 ± 14.74% vs. 14.17 ± 5.94%, P = 0.120) in the NEVO as compared with Xience. CONCLUSION: The NEVO stent with a reservoir technology seems to exhibit more neointimal proliferation as compared to Xience stent. The findings of our study, which currently represent the unique data existing on this reservoir technology, would need to be confirmed in a large population.

Quantified coronary frequency domain optical coherence tomography signal analysis for the evaluation of erythrocyte-rich thrombus: ex-vivo validation study.

Previous study has demonstrated that erythrocyte-rich thrombi contain more inflammatory cells and reflect high thrombus burden, leading to impaired myocardial reperfusion in myocardial infarction. The aim of this study is to investigate the utility of quantified frequency domain optical coherence tomography (FD-OCT) signal analysis in evaluating the erythrocyte-rich thrombus with ex-vivo materials. We evaluated 54 specimens of coronary artery thrombus obtained by thrombectomy catheter from 8 patients who underwent primary percutaneous coronary intervention. The thrombi were immersed in saline immediately after thrombectomy and FD-OCT image acquisition was performed ex-vivo. Quantitative analysis for all contiguous frames was performed by the dedicated automated software (OCT system software, Light Lab Inc.). For the maximum thrombus area, mean signal intensity (MSI) and normalized standard deviation of signal (NSD) was evaluated. All thrombi were stained using double staining of phosphotungstic acid-hematoxylin and eosin to enable automatic extraction of erythrocyte from fibrin. Computer-assisted analysis was performed using dedicated image processing software (WinROOF, Mitani Corp., Tokyo, Japan) for color identification of the erythrocyte area. Erythrocyte-rich thrombus, defined as % erythrocyte [(erythrocyte area/total thrombus area) × 100] ≥ 10%, showed significantly lower MSI [4.39 ± 0.24 vs. 4.74 ± 0.35, p = 0.002] than that of <10%. The cut-off point for prediction of erythrocyte-rich thrombus was defined as MSI ≤ 4.56, sensitivity: 87.5%, specificity: 82.9%, area under the curve: 0.836, respectively). The present ex-vivo study suggested the utility of quantified FD-OCT signal analysis on the detection of erythrocyte-rich thrombus.

Serial optical coherence tomography assessment of malapposed struts after everolimus-eluting stent implantation. A subanalysis from the HEAL-EES study.

BACKGROUND: Incomplete stent apposition (ISA) is related to stent thrombosis, which is a serious adverse event. We aim to assess the time-course of ISA after 2nd generation everolimus-eluting stent (EES) implantation. METHODS: In HEAL-EES study, we enrolled 36 patients who underwent percutaneous coronary intervention (PCI) with EES. OCT imaging was performed at baseline and follow-up. Patients were randomized 1:1:1 into 3 groups according to the time in which follow-up was performed: group A (6-month), group B (9-month), and group C (12-month). In this subanalysis, patients who had ISA segments at baseline and/or follow-up OCT were analyzed. RESULT: At baseline, among 41 lesions in 36 patients, 20 lesions in 18 patients had ISA segments and were analyzed. At baseline, there were 3.0% ISA struts in group A (n=8), 2.8% in group B (n=4), and 4.5% in group C (n=8). At follow-up, ISA struts were present in 0.09%, 0.16% and 0.64%; respectively in groups A, B, and C. At follow-up, there was a significant decrease in the frequency of ISA: group A 3.0% vs. 0.09% (p<0.001), group B 2.8% vs. 0.16% (p<0.001), and group C 4.5% vs. 0.64% (p<0.001). In group A, there was one late acquired ISA at follow-up. CONCLUSIONS: In patients undergoing 2nd generation EES implantation, area of acute ISA assessed by OCT, was almost resolved at 6-month follow-up.

Overtime evaluation of the vascular HEALing process after everolimus-eluting stent implantation by optical coherence tomography. The HEAL-EES study.

PURPOSE: Second-generation drug-eluting stent (DES) have shown a better safety and efficacy as compared to first generation DES due to an improved vascular healing process. This process has not been so far evaluated in vivo in an overtime fashion by optical coherent tomography (OCT). We sought to evaluate the vascular healing process after everolimus-eluting stent (EES) implantation at 6, 9 and 12months, by OCT. METHODS: Consecutive 36 patients undergoing percutaneous coronary intervention with EES were randomized 1:1:1 to receive OCT imaging at 6 (group A), 9 (group B) or 12-month follow-up (group C). One patient from group C was excluded because of target lesion revascularization at 1-month, whereas 5 patients withdraw the informed consent. Finally, 30 patients were analyzed. RESULTS: Neointimal thickness was not different between 3 groups (group A: 99.50 [94.06-127.79] µm, group B: 107.26 [83.48-133.59] µm, group C: 127.67 [102.51-138.49] µm; p=0.736). Although the percentage of "uncovered struts" was significantly higher in group A as compared to the other groups (8.0% vs. 4.4% vs. 2.9%, respectively; p=0.180), the ratio of uncovered to total struts per section <30% was similar between 3 groups (0.3% vs. 0.3% vs. 0%, respectively; p=1.000). CONCLUSION: Healing process following EES implantation seems almost completed at 6-month follow-up. These data, which need to be confirmed in a larger study, may support the decision to shorten dual antiplatelet therapy.

Randomized comparison between polymer-free versus polymer-based paclitaxel-eluting stent: two-year final clinical results.

BACKGROUND: Most drug-eluting stents currently in use are coated with a polymer carrying the drug that is released for several weeks. However, a durable polymer may provoke hypersensitive reaction, delayed artery healing, and eventually stent thrombosis. The aim of this study was to investigate the safety and efficacy of a polymer-free paclitaxel-eluting stent (PF-PES) versus a polymer-based PES (PB-PES). METHODS AND RESULTS: Eligible patients undergoing percutaneous coronary intervention were randomized 1:1 to receive either PF-PES or PB-PES. The primary end point was late loss at 9 months. Intravascular ultrasound analysis at 9 months and final 2-year clinical follow-up were also performed. From October 2007 to April 2009, 164 patients were enrolled and randomized into 2 groups (PF-PES: n = 84; PB-PES: n = 80). Mean in-stent lumen loss was 0.90 ± 0.59 mm for PF-PES and 0.49 ± 0.52 mm for PB-PES (P < 0.001). Mean neointimal area by intravascular ultrasound was higher in PF-PES than in PB-PES (1.42 ± 1.09 versus 0.51 ± 0.61 mm(2); P < 0.001). At 2 years, a composite end point of all-cause death, any myocardial infarction, and target vessel revascularization occurred in 36.9% for PF-PES and 16.3% for PB-PES (P = 0.004), mainly driven by a higher rate of target vessel revascularization (PF-PES: 35.7%; PB-PES: 13.8%; P = 0.001). One late stent thrombosis was observed in PF-PES. CONCLUSIONS: Compared with PB-PES, PF-PES was associated with increased neointimal proliferation and subsequent clinical restenosis. Polymer plays an essential role in the performance of drug-eluting stents. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01375855.

Predictors and clinical implications of stent thrombosis in patients with ST-segment elevation myocardial infarction: Insights from the EXAMINATION trial.

BACKGROUND: Few data are available about safety of second generation drug eluting stents in an all-comer ST elevation myocardial infarction (STEMI) population. We sought to investigate the predictors and clinical implications of 1-year stent thrombosis (ST) in patients with STEMI, included in the EXAMINATION trial. METHODS AND RESULTS: The EXAMINATION trial is an all-comer prospective, randomized 1:1 controlled trial, testing everolimus-eluting stent (EES) vs. cobalt chromium bare metal stent (BMS) in STEMI patients. It included 1498 patients, randomized to EES (n = 751) or BMS (n = 747). At 1 year, definite/probable stent thrombosis, defined according to ARC criteria, occurred in 26 patients (1.73%), including 18 definite and 8 probable events. The incidence of ST was lower in patients treated with EES than in those treated with BMS (HR 0.16, 95% CI 0.03-0.29, p = 0.017). Patients with ST have higher 1-year rates of cardiac death (30.8% vs. 2.5%, p<0.001), myocardial infarction (30.8% vs. 0.5%, p<0.001) and target vessel revascularization (65.4% vs. 4.2%, p<0.001) compared with those without. Independent predictors of 1-year definite/probable ST were BMS implantation at the index procedure (HR 3.41, 95% CI 1.35-8.60), ST segment resolution of at least 70% in the EKG post-PCI (HR 0.30, 95% CI 0.13-0.70) and Killip class on admission (HR 2.57, 95% CI 1.70-3.90). CONCLUSIONS: ST had low frequency in the first year after implantation of EES/BMS in STEMI patients, but it is associated with adverse events. BMS implantation, lack of ST-segment resolution and high Killip class on admission were independent predictors of 1-year ST.

Angiographic and clinical outcomes of 100 consecutive severe calcified lesions requiring rotational atherectomy prior to sirolimus-eluting stent implantation in hemodialysis and non-hemodialysis patients.

Both severe calcified lesions and hemodialysis (HD) are predictors for high rates of restenosis, even in the drug-eluting stent era. We sought to investigate the angiographic and clinical outcome in a population of HD versus non-hemodialysis (non-HD) patients with severe calcified lesions requiring rotational atherectomy. One hundred consecutive lesions (28 lesions in the HD group, 72 in the non-HD group) from 82 patients (19 patients in the HD group, 63 in the non-HD group) requiring rotational atherectomy prior to sirolimus-eluting stent (SES) implantation were analyzed post-procedure and at 8 months. Clinical outcomes were assessed at 12 months. Inclusion criteria were calcified lesions with >270° of superficial calcification on the intravascular ultrasound (IVUS), lesions that the IVUS could not cross, or undilatable lesions. There were no differences in patient characteristics except for age. Although both baseline and post-procedure angiographic findings were similar between the two groups, late loss in stented segment was significantly greater in the HD group than in the non-HD group (HD vs. non-HD: 0.69 ± 0.74 mm vs. 0.34 ± 0.50; P = 0.030). Also, the HD group revealed significantly worse clinical outcomes. In conclusion, mid-term results of highly complex, severely calcified lesions requiring rotational atherectomy in non-HD patients were permissible as compared to on-label lesions. However, in HD patients, both angiographic and clinical outcomes were still suboptimal in this lesion subset, even using SES.

"Black hole" restenosis after sirolimus-eluting stent implantation.

In several reports, the "black hole" (BH) phenomenon was reported as a homogeneous echolucent appearance by intravascular ultrasound. We discuss an experience with angioscopic and pathological assessment for the BH phenomenon.