Assessment of Echo-Attenuated Plaque by Optical Coherence Tomography and its Impact on Post-Procedural Creatine Kinase-Myocardial Band Elevation in Elective Stent Implantation

Complementary Roles of Near-Infrared Spectroscopy and Intravascular Ultrasound in the Prediction of Periprocedural Myocardial Injury

BACKGROUND

Lipid-rich plaque detected by near-infrared spectroscopy (NIRS) and attenuated plaque detected by intravascular ultrasound (IVUS) predict periprocedural myocardial injury (MI) following percutaneous coronary intervention (PCI). Although echolucent plaque detected by IVUS was reported to be associated with a no-reflow phenomenon in acute myocardial infarction, it remains unclear whether echolucent plaque is predictive of periprocedural MI following elective PCI. We aimed to elucidate whether echolucent plaque is independently associated with periprocedural MI after elective PCI and whether the predictive ability for periprocedural MI is improved by the combination of NIRS and IVUS.

METHODS

This retrospective study included 121 lesions of 121 patients who underwent elective NIRS-IVUS-guided stent implantation. Periprocedural MI was defined as post-PCI cardiac troponin T > 70 ng/L. A maximum 4-mm lipid core burden index > 457 was regarded as lipid-rich plaque. Echolucent plaque was defined as the presence on IVUS of an echolucent zone and attenuated plaque as an attenuation arc > 90°.

RESULTS

Periprocedural MI occurred in 39 lesions. In multivariable analysis, echolucent plaque, attenuated plaque, and lipid-rich plaque were independent predictors of periprocedural MI. Adding echolucent plaque and attenuated plaque to lipid-rich plaque improved the predictive performance (C statistic 0.825 vs 0.688; P = 0.001). Periprocedural MI increased with the number of predictors: 3% [1/39], 29% [10/34], 47% [14/30], and 78% [14/18] for 0, 1, 2, and 3 predictors, respectively (P < 0.001).

CONCLUSIONS

Echolucent plaque is a major predictor of periprocedural MI, independently from lipid-rich plaque and attenuated plaque. Compared with NIRS alone, the combination of NIRS with IVUS signatures improves the predictive ability.

Evolocumab for prevention of microvascular dysfunction in patients undergoing percutaneous coronary intervention: the randomised, open-label EVOCATION trial

BACKGROUND

Statins have been shown to prevent microvascular dysfunction that may cause periprocedural myocardial infarction after percutaneous coronary intervention (PCI). Evolocumab has more potent lipid-lowering properties than statins.  Aims: The aims of this study were to investigate whether evolocumab pretreatment on top of statin therapy could prevent periprocedural microvascular dysfunction.  Methods: This study included 100 patients with stable coronary artery disease who were scheduled to undergo PCI and had high low-density lipoprotein cholesterol (LDL-C) under statin therapy. Patients were randomised to receive evolocumab 140 mg every 2 weeks for 2 to 6 weeks before PCI (evolocumab group: N=54) or not (control group: N=46). The primary endpoint was the index of microvascular resistance (IMR) after PCI. Troponin T was measured before and 24 hours after PCI.  Results: Geometric mean LDL-C was 94.1 (95% confidence interval [CI]: 86.8-102.1) mg/dl and 89.4 (95% CI: 83.5-95.7) mg/dl at baseline, and 25.6 (95% CI: 21.9-30.0) mg/dl and 79.8 (95% CI: 73.9-86.3) mg/dl before PCI, in the evolocumab group and in the control group, respectively. PCI was performed 22.1±8.5 days after allocation. Geometric mean IMR was 20.6 (95% CI: 17.2-24.6) in the evolocumab group and 20.6 (95% CI: 17.0-25.0) in the control group (p=0.98). There was no significant difference in the geometric mean of post-PCI troponin T (0.054, 95% CI: 0.041-0.071 ng/ml vs 0.054, 95% CI: 0.038-0.077 ng/ml; p=0.99) and in the incidence of major periprocedural myocardial infarction between the 2 groups (44.4% vs 44.2%; p=1.00).  Conclusions: Evolocumab pretreatment did not prevent periprocedural microvascular dysfunction in patients on modern medical management with statins.

Using Optical Coherence Tomography to Identify Lipid and Its Impact on Interventions and Clinical Events - A Scoping Review

BACKGROUND

Optical coherence tomographic (OCT) imaging has enabled identification of lipid, with increasing interest in how it may affect coronary interventions and clinical outcomes. This review summarizes the available evidence around OCT identification of lipid and its effect on interventions, clinical events, and the natural history of coronary disease.

METHODS AND RESULTS

We conducted a scoping review using the Medline, HealthStar, and Embase databases for articles published between 1996 and 2021. We screened 1,194 articles and identified 51 for inclusion in this study, summarizing the key findings. The literature supports a common OCT definition of lipid as low-signal regions with diffuse borders, validated against histology and other imaging modalities with acceptable intra- and inter-rater reliability. There is evidence that OCT-identified lipid at the site of stent implantation increases the risk of edge dissection, incomplete stent apposition, in-stent tissue protrusion, decreased coronary flow after stenting, side branch occlusion, and post-procedural cardiac biomarker increases. In mostly retrospective studies, lipid indices measured at non-stented sites are associated with plaque progression and the development of recurrent ischemic events.

CONCLUSIONS

There is extensive literature supporting the ability of OCT to identify lipid and demonstrating a substantial impact of lipid on percutaneous coronary intervention outcomes. Future work to prospectively evaluate the effect of the characteristics of lipid-rich plaques on long-term clinical outcomes is needed.

The Predictive Value of Baseline Target Lesion SYNTAX Score for No-Reflow during Urgent Percutaneous Coronary Intervention in Acute Myocardial Infarction

OBJECTIVES

To evaluate the predictive value of target lesion SYNTAX score (TL-SS) for no-reflow in the patients with acute myocardial infarction undergoing urgent percutaneous coronary intervention (PCI).

BACKGROUND

Risk assessment, prevention, and prompt management of no-reflow in urgent PCI are crucial but remain challenging. SYNTAX score emerged as a tool for prediction, but may contain redundant information.

METHODS

After screening of consecutive patients who underwent urgent PCI in Fuwai Hospital from January 2013 to December 2013, 487 patients with 528 lesions were involved. The endpoint was no-reflow during the PCI procedure.

RESULTS

No-reflow occurred in 52 patients (10.7%) and 53 lesions (10.0%). High TL-SS levels were strongly associated with increased risks of no-reflow in the urgent PCI procedure (all adjusted P < 0.05). TL-SS displayed good discrimination ability for no-reflow (C-statistics = 0.76, 95% CI 0.72-0.80), which was better than that of SYNTAX score (P=0.016). Following categorizing the lesions into two groups according to the Youden Index, the high-risk group (TL-SS ≥8) showed significantly higher no-reflow rate compared with the low-risk group (TL-SS <8) (20.6% vs. 3.6%, odds ratio 6.86, 95% confidence interval 3.50-13.41, P < 0.001). In the target lesions that underwent balloon predilation, maximum predilation pressure >10 atm was associated with higher rate of no-reflow in the high-risk group (odds ratio 3.81, 95% confidence interval 1.10-13.17).

CONCLUSIONS

TL-SS is a potential predictor for risk stratification of no-reflow in urgent PCI. In the high TL-SS lesions that underwent balloon predilation, maximum predilation pressure >10 atm was associated with higher risk of no-reflow.

The role of intracoronary imaging in translational research

Atherosclerotic cardiovascular disease is a key public health concern worldwide and leading cause of morbidity, mortality and health economic costs. Understanding atherosclerotic plaque microstructure in relation to molecular mechanisms that underpin its initiation and progression is needed to provide the best chance of combating this disease. Evolving vessel wall-based, endovascular coronary imaging modalities, including intravascular ultrasound (IVUS), optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS), used in isolation or as hybrid modalities, have been advanced to allow comprehensive visualization of the pathological substrate of coronary atherosclerosis and accurately measure temporal changes in both the vessel wall and plaque characteristics. This has helped further our appreciation of the natural history of coronary artery disease (CAD) and the risk for major adverse cardiovascular events (MACE), evaluate the responsiveness to conventional and experimental therapeutic interventions, and assist in guiding percutaneous coronary intervention (PCI). Here we review the use of different imaging modalities for these purposes and the lessons they have provided thus far.

Progression of ultrasound plaque attenuation and low echogenicity associates with major adverse cardiovascular events

Aims

Intravascular ultrasound (IVUS) imaging can visualize vulnerable plaque features including attenuation (AP) and echolucency (ELP). While IVUS-derived vulnerable plaque features associate with microvascular obstruction during percutaneous coronary intervention, the relationship between these plaque features and clinical outcomes has not been established. This analysis aimed to evaluate the association of AP/ELP with cardiovascular events.

Methods and results

Serial IVUS imaging was reviewed in 1497 patients, followed for 18–24 months, with coronary artery disease from two clinical trials. Attenuated plaque and ELP were identified to measure each characteristics (AP arc, ELP area, and lengths), which permitted calculation of an AP index (API) and ELP volume. Attenuated plaque/ELP progression was defined as patients with any increase of API or ELP volume on serial imaging. The major cardiovascular events (MACEs) were defined as death, myocardial infarction, stroke, and coronary revascularization. AP or ELP was identified in 282 patients (18.8%) at baseline and 160 (10.7%) patients demonstrated an increase in AP or ELP at follow-up. The incidence of MACE was higher in patients with baseline AP/ELP than those without (8.2% vs. 3.9%, P = 0.002). Patients with AP/ELP progression were more likely to be acute coronary syndrome (41.9 vs. 33.2%, P = 0.03) and have greater baseline percent atheroma volume (40.0% vs. 35.8%, P &lt; 0.001) than those without. On multivariable analysis, AP/ELP progression was more strongly associated with MACE [baseline AP/ELP: hazard ratio (HR) 1.76, 95% confidence interval (CI) 1.05–2.97, AP/ELP progression: HR 2.19, 95% CI 1.24–3.86].

Conclusion

Attenuation/ELP progression was associated with a higher prevalence of cardiovascular events, supporting a potential role for the identification of high-risk vulnerable plaques in patients with coronary artery disease.

Culprit Plaque Characteristics in Patients With Sleep-Disordered Breathing Undergoing Percutaneous Coronary Intervention: An Intravascular Ultrasound Study

Background

Sleep‐disordered breathing (SDB) is a novel cardiovascular risk factor. However, the coronary plaque characteristics of patients with SDB with coronary artery disease are still unclear.

Methods and Results

This study included 289 consecutive patients with coronary artery disease undergoing percutaneous coronary intervention. Plaque characteristics of the culprit lesion were assessed by preintervention intravascular ultrasound. The presence of SDB was defined as a 3% oxygen desaturation index of ≥15 events per hour measured by nocturnal pulse oximetry. Of 289 patients, the median 3% oxygen desaturation index was 9.6 (interquartile range, 5.1–16.6), and 88 patients (30.4%) were defined as having SDB. Compared with the no‐SDB group, the SDB group had a larger total atheroma volume of the culprit lesion (224.5 mm³ versus 190.8 mm³, P=0.05). The median maximum attenuation and calcification angle were 140° and 130°, respectively. Attenuated plaque with a maximum attenuation angle >140° was more frequently observed in the SDB group compared with the no‐SDB group (34.9% versus 22.6%; P=0.03). However, there were no statistically significant differences between groups in the maximum calcium angle and the frequency of calcific plaques with a maximum calcium angle >130°. Multivariable logistic regression analysis showed that the presence of SDB was a significant predictor of a greater ultrasound attenuation angle (>140°) (odds ratio, 1.86; 95% confidence interval, 1.02–3.39; P=0.04).

Conclusions

SDB was associated with larger atheroma plaque volume and a greater ultrasound attenuation, which are discriminators of plaque vulnerability. Further studies are needed to clarify the effects of SDB treatment on coronary plaque lesions.

The clinical significance of echo-attenuated plaque in stable angina pectoris compared with acute coronary syndromes: A combined intravascular ultrasound and optical coherence tomography study

BACKGROUND

Echo-attenuated plaque (EA) on intravascular ultrasound (IVUS) is related to poor outcomes after percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) patients. However, the clinical significance of EA in stable angina pectoris (SAP) patients compared with that in ACS patients remains unclear. We assessed the relationships between EA and unstable plaque characteristics in patients with ACS and SAP.

METHODS

We investigated 609 coronary lesions in 609 patients (234 with ACS; 375 with SAP) undergoing pre-intervention IVUS and optical coherence tomography (OCT). The differences in plaque morphology and post-PCI outcomes were assessed according to the clinical status of ACS or SAP and the presence or absence of EA.

RESULTS

EA was more frequent in patients with ACS than in those with SAP (44.0% vs. 25.1%, p < 0.001). SAP-EA lesions showed thicker fibrous cap (157 ± 97 μm vs. 100 ± 58 μm, p < 0.001), smaller lipid arc (208 ± 76° vs. 266 ± 99°, p < 0.001), smaller plaque burden (83.0 ± 6.1% vs. 86.5 ± 4.1%, p < 0.001), and lower frequency of transient slow-reflow phenomenon during PCI (21.3% vs. 51.5%, p < 0.001) than ACS-EA lesions, but similar plaque vulnerability compared with ACS-non-EA lesions. SAP-EA lesions had less frequent OCT-thrombus than ACS-non-EA lesions (20.2% vs. 71.2%, p < 0.001).

CONCLUSIONS

SAP-EA lesions had less plaque vulnerability than ACS-EA lesions, but were comparable to ACS-non-EA lesions. Less frequent thrombus formation might differentiate SAP-EA lesions from ACS-non-EA lesions. A combined IVUS and OCT approach might be useful to assess plaque vulnerability in SAP-EA lesions compared with ACS lesions.

Predictive value of plaque morphology assessed by frequency-domain optical coherence tomography for impaired microvascular perfusion after elective stent implantation: the intracoronary electrocardiogram study

Aims

This study was undertaken to assess the association between plaque features at culprit lesions assessed by frequency-domain optical coherence tomography (FD-OCT) and impaired microvascular perfusion estimated by intracoronary electrocardiogram (IcECG) after elective percutaneous coronary intervention (PCI). Furthermore, we investigated whether IcECG could predict future cardiac events.

Methods and results

This study consisted of 84 patients who underwent both FD-OCT and IcECG during PCI. Patients were classified into two groups based on ST-segment elevation (ST-E) on IcECG after the procedure; ST-E (-) group (n = 53) and ST-E (+) group (n = 31). Minimum fibrous cap thickness was significantly thinner in the ST-E (+) group than in the ST-E (-) group (240 μm [IQR 180 to 310] vs. 100 μm [IQR 60 to 120], P < 0.001). Plaque rupture (7.5% vs. 35.5%, P = 0.001), lipid-rich plaque (75.5% vs. 100%, P < 0.001), the thin cap fibroatheroma (0% vs. 25.8%, P < 0.001) on pre-FD-OCT, protrusion (18.9% vs. 56.7%, P < 0.001), and intra-stent dissection (15.1% vs. 50.0%, P < 0.001) on post-FD-OCT were significantly more frequently found in the ST-E (+) group than in the ST-E (-) group. The incidence of MACE (cardiac death, myocardial infarction, revascularization, hospitalization for heart failure) during 1-year was significantly higher in the ST-E (+) group than in the ST-E (-) group (5.7% vs. 19.4%, P < 0.05).

Conclusion

Plaque features assessed by FD-OCT might be associated with impaired microvascular perfusion and ST-segment elevation on IcECG after the procedure could predict 1-year cardiac events after elective PCI.

Impact of high-density lipoprotein 3 cholesterol subfraction on periprocedural myocardial injury in patients who underwent elective percutaneous coronary intervention

Background

Periprocedural myocardial injury (PMI) is a major complication of percutaneous coronary intervention (PCI) and is associated with atherosclerotic coronary plaque and worse clinical outcomes. High-density lipoprotein cholesterol (HDL-C) is a protective factor for cardiovascular disease. However, the role of HDL-C subfractions, such as HDL2 cholesterol (HDL2-C) or HDL3 cholesterol (HDL3-C), in cardiovascular disease remains unclear. The purpose of the study was to investigate the relationship between HDL2-C and HDL3-C subfractions and the incidence of PMI in patients who underwent elective PCI.

Methods

We enrolled 129 patients who underwent elective PCI for stable angina pectoris. PMI was defined as an increase in high-sensitivity troponin T levels > 5 times the upper normal limit (> 0.070 ng/mL) at 24 h after PCI. Serum HDL-C subfractions (HDL2-C and HDL3-C) were assessed using ultracentrifugation in patients with and those without PMI.

Results

HDL3-C levels were significantly lower in patients with PMI than in those without (15.1 ± 3.0 mg/dL vs. 16.4 ± 2.9 mg/dL, p = 0.016) and had an independent and inverse association with PMI (odds ratio, 0.86; 95% confidence interval, 0.74–0.99; p = 0.038). When divided by the cut-off value of HDL3-C for PMI (14.3 mg/dL), the incidence of PMI was significantly higher in low HDL3-C patients than in high HDL3-C patients (51.2% vs. 30.2%, p = 0.020).

Conclusions

HDL3-C was an independent inverse predictor of PMI in patients who underwent elective PCI.

Impact of attenuated-signal plaque observed by intravascular ultrasound on vessel response after drug-eluting stent implantation

BACKGROUND AND AIMS

The aim of this study was to investigate the impact of attenuated-signal plaque (ASP) observed by intravascular ultrasound (IVUS) on vessel response after drug-eluting stent implantation.

METHODS

Data were derived from the IVUS cohort of the J-DESsERT trial comparing paclitaxel- and sirolimus-eluting stents. Serial IVUS analysis (pre- and post-intervention, and 8-month follow-up) was performed in 136 non-AMI lesions. ASP was defined as hypoechoic plaque with ultrasound attenuation without calcification. Calcified plaque (CP) was defined as brightly echoreflective plaque with acoustic shadowing. ASP and CP scores were calculated by grading their measured angle as 0 to 4 for 0°, <90°, 90-180°, 180-270° and >270°, respectively. The entire stented segment was analyzed at 1-mm intervals.

RESULTS

At pre-intervention, ASP was observed in 40.4% of lesions, and this group had greater % neointimal volume (%NIV) at follow-up than the no-ASP group (p = 0.011). ASP score at pre-intervention positively correlated with %NIV (p = 0.023). During the follow-up, ASP score significantly decreased (p < 0.001), and CP score significantly increased (p < 0.001), with a negative correlation between them (p < 0.001). A decrease in the ASP score was associated with less %NIV in PES (p = 0.031), but not in SES (p = 0.229).

CONCLUSIONS

The greater extent of plaque with IVUS-signal attenuation at pre-intervention and its persistence during follow-up were associated with neointimal proliferation, possibly representing sustained inflammatory status, depending on the type of DES used.

Pericoronary adipose tissue ratio is a stronger associated factor of plaque vulnerability than epicardial adipose tissue on coronary computed tomography angiography

This study was designed to clarify the influence of pericoronary adipose tissue (PAT) on plaque vulnerability using coronary computed tomography angiography (CCTA). A total of 103 consecutive patients who underwent CCTA and subsequent percutaneous coronary intervention (PCI) using intravascular ultrasound (IVUS) for coronary artery disease were enrolled. The PAT ratio was calculated as the sum of the perpendicular thickness of the visceral layer between the coronary artery and the pericardium, or the coronary artery and the surface of the heart at the PCI site, divided by the PAT thickness without a plaque in the same vessel. PAT ratios were divided into low, mid and high tertile groups. Epicardial adipose tissue (EAT) thickness was measured at the eight points surrounding the heart. Multivariate logistic analysis was performed to determine whether the PAT ratio is predictive of vulnerable plaques (positive remodeling, low attenuation and/or spotty calcification) on CCTA or echo-attenuated plaque on IVUS. The Hounsfield unit of obstructive plaques >50% was lower in the high PAT group than in the mid and low PAT groups (47.5 ± 28.8 vs. 53.1 ± 29.7 vs. 64.7 ± 27.0, p = 0.04). In multivariate logistic analysis, a high PAT ratio was an independent, associated factor of vulnerable plaques on CCTA (OR: 3.55, 95% CI: 1.20-10.49), whereas mean EAT thickness was not (OR: 1.22, 95% CI: 0.82-1.83). We observed a similar result in predicting echo-attenuated plaque on IVUS. PAT ratio on CCTA was an associated factor of vulnerable plaques, while EAT was not. These results support the important concept of local effects of cardiac adipose tissue on plaque vulnerability.

Assessment of Coronary Plaque Vulnerability in Acute Coronary Syndromes using Optical Coherence Tomography and Intravascular Ultrasound. A Systematic Review

The aim of this systematic review was to analyze studies characterizing vulnerable coronary plaques using optical coherence tomography (OCT) and intravascular ultrasound (IVUS), in order to identify the most efficient invasive technique permitting plaque characterization in patients with acute myocardial infarction.

Method: A total number of 432 studies were identified, 420 through database searching and 12 through manual searching. Eight duplicate studies were removed, leaving a total number of 424 studies to be screened. Twenty-six studies only available in Abstract-only form were excluded, resulting in 398 studies checked for eligibility. Eleven studies fulfilled the eligibility criteria and were included in this systematic analysis. Plaque vulnerability was investigated in plaques with thin cap fibroatheroma (TCFA) versus those with thick cap fibroatheroma, in ruptured coronary plaques versus non-ruptured coronary plaques, in culprit versus non-culprit lesions and in lipid-rich versus non-lipid-rich plaques.

Results: A total of 1,568 coronary plaques in 1,225 patients with acute coronary syndromes (ACS) who underwent both IVUS and OCT for analysis of plaque features were included in the final analysis. The review identified the following IVUS-derived features as significantly correlated with plaque vulnerability: plaque burden (p <0.001), remodeling index (p <0.001), external elastic membrane cross-sectional area (p <0.001), and the amount of necrotic core (p <0.001), while OCT-derived features characterizing unstable plaque were TCFA (p <0.001), lipid arch (p <0.001), accumulation of macrophages (p = 0.03), and presence of intracoronary thrombus (p <0.001).

Conclusion: Both IVUS and OCT are invasive imaging techniques able to provide relevant information on the vulnerability of coronary atheromatous plaques, identifying, as they do, various plaque features significantly associated with unstable plaques. Information provided by the two techniques is complementary, and both methods can serve as a useful clinical diagnostic tool, especially in cases of ACS patients undergoing a revascularization procedure.

Attenuated-Signal Plaque Progression Predicts Long-Term Mortality After Heart Transplantation: IVUS Assessment of Cardiac Allograft Vasculopathy

BACKGROUND

Although cardiac allograft vasculopathy (CAV) is typically characterized by diffuse coronary intimal thickening with pathological vessel remodeling, plaque instability may also play an important role in CAV. Previous studies of native coronary atherosclerosis have demonstrated associations between attenuated-signal plaque (ASP), plaque instability, and adverse clinical events.

OBJECTIVES

This study's aim was to characterize the association between ASP and long-term mortality post-heart transplantation.

METHODS

In 105 heart transplant recipients, serial (baseline and 1-year post-transplant) intravascular ultrasound was performed in the first 50 mm of the left anterior descending artery. The ASP score was calculated by grading the measured angle of attenuation from grades 0 to 4 (specifically, 0°, 1° to 90°, 91° to 180°, 181° to 270°, and >270°) at 1-mm intervals. The primary endpoint was all-cause death or retransplantation.

RESULTS

At 1-year post-transplant, 10.5% of patients demonstrated ASP progression (newly developed or increased ASP). Patients with ASP progression had a higher incidence of acute cellular rejection during the first year (63.6% vs. 22.3%; p = 0.006) and tendency for greater intimal growth (percent intimal volume: 9.2 ± 9.3% vs. 4.4 ± 5.3%; p = 0.07) than those without. Over a median follow-up of 4.6 years, there was a significantly lower event-free survival rate in patients with ASP progression at 1-year post-transplant compared with those without. In contrast, maximum intimal thickness did not predict long-term mortality.

CONCLUSIONS

ASP progression appears to reflect chronic inflammation related to acute cellular rejection and is an independent predictor of long-term mortality after heart transplantation. Serial assessments of plaque instability may enhance identification of high-risk patients who may benefit from closer follow-up and targeted medical therapies.

Impact of attenuated plaques on TIMI grade flow and clinical outcomes of coronary artery disease patients: a systematic review and meta analysis

BACKGROUND

Plaques with a large necrotic core or lipid pool and thin-cap fibroatheroma manifest as attenuated plaques on intravascular ultrasound (IVUS). Their impact on TIMI grade flow and clinical outcomes remains undefined. We performed a systematic review and meta-analysis to summarize the association between attenuated plaque and distal embolization and clinical outcomes of coronary artery disease (CAD) from pooled data of published eligible cohort studies.

METHODS

We searched the literature on TIMI grade flow and clinical outcomes on PubMed, Ovid, EMBASE, the Cochrane Library, CNKI and WanFang databases. Study heterogeneity and publication bias were estimated.

RESULTS

A total of 3,833 patients were enrolled in nine studies. Five studies investigated TIMI grade flow and attenuated plaques. They revealed no difference in TIMI grade flow before percutaneous coronary intervention (PCI) between the attenuated and non-attenuated plaque group (RR =1.25; 95% CI: 0.65 to 2.41; P=0.50). After balloon dilation and stent implantation, the incidence of TIMI 0~2 grade flow in the attenuated plaque group was statistically significant higher than that of the non-attenuated plaque group (RR =4.73; 95% CI: 3.03 to 7.40; P<0.001). Five other studies investigated major cardiovascular events (MACEs) and attenuated plaques and found no difference in MACE rates within three years of follow up.

CONCLUSIONS

Our study presents the evidence that plaque with ultrasound signal attenuation would induce slow/no reflow phenomenon and distal embolization during PCI, but this appearance has no impact on MACE rates within three years.

Coronary plaque morphology on multi-modality imagining and periprocedural myocardial infarction after percutaneous coronary intervention

Percutaneous coronary intervention (PCI) may be complicated by periprocedural myocardial infarction (PMI) as manifested by elevated cardiac biomarkers such as creatine kinase (CK)-MB or troponin T. The occurrence of PMI has been shown to be associated with worse short- and long-term clinical outcome. However, recent studies suggest that PMI defined by biomarker levels alone is a marker of atherosclerosis burden and procedural complexity but in most cases does not have independent prognostic significance. Diagnostic multi-modality imaging such as intravascular ultrasound, optical coherence tomography, coronary angioscopy, near-infrared spectroscopy, multidetector computed tomography, and magnetic resonance imaging can be used to closely investigate the atherosclerotic lesion in order to detect morphological markers of unstable and vulnerable plaques in the patients undergoing PCI. With the improvement of technical aspects of multimodality coronary imaging, clinical practice and research are increasingly shifting toward defining the clinical implication of plaque morphology and patients outcomes. There were numerous published data regarding the relationship between pre-PCI lesion subsets on multi-modality imaging and post-PCI biomarker levels. In this review, we discuss the relationship between coronary plaque morphology estimated by invasive or noninvasive coronary imaging and the occurrence of PMI. Furthermore, this review underlies that the value of the multimodality coronary imaging approach will become the gold standard for invasive or noninvasive prediction of PMI in clinical practice.

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Periprocedural myocardial infarction (PMI) has been shown to be associated with worse short- and long-term clinical outcome.

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Clinical practice and research are increasingly shifting toward the plaque morphology and patients outcomes.

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This review discusses the relationship between plaque morphology estimated by coronary imaging and the occurrence of PMI.

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This review underlies the value of the multimodality coronary imaging approach for prediction of PMI in clinical practice.

Optical frequency domain imaging vs. intravascular ultrasound in percutaneous coronary intervention (OPINION trial): Study protocol for a randomized controlled trial

BACKGROUND

Optical coherence tomography is becoming increasingly widespread as an adjunctive intravascular diagnostic technique in percutaneous coronary intervention (PCI), because of its ability to visualize coronary structures at high resolution. Several studies have reported that intravascular ultrasound (IVUS) guidance in PCI might be helpful to reduce subsequent stent thrombosis, restenosis, repeat revascularization, myocardial infarction, and cardiac death. The OPtical frequency domain imaging vs. INtravascular ultrasound in percutaneous coronary InterventiON (OPINION) trial is aimed at evaluating the impact of optical frequency domain imaging (OFDI) guidance in PCI on clinical outcomes compared with IVUS guidance.

METHODS AND DESIGN

The OPINION trial is a multicenter, prospective, randomized, controlled, open-label, parallel group, non-inferiority trial in Japan. The eligible patients are randomly assigned to receive either OFDI-guided PCI or IVUS-guided PCI. PCI is performed using the biolimus-eluting stent in accordance with a certain criteria of OFDI and IVUS for optimal stent deployment. All patients will undergo a follow-up angiography at 8 months. The primary endpoint is target vessel failure composed of cardiac death, myocardial infarction attributed to the target vessel, and clinically-driven target vessel revascularization at 12 months.

CONCLUSION

When completed, the OPINION trial will contribute to define the clinical value of the OFDI guidance in PCI.

Technical Considerations and Practical Guidance for Intracoronary Optical Coherence Tomography

Optical coherence tomography (OCT) is an intravascular imaging technology analogous to intravascular ultrasound, using near-infrared light rather than ultrasound, thereby providing higher-resolution images. This review provides a practical guide to OCT imaging, with a particular emphasis on the techniques and approaches to optimize image acquisition, improve the evaluation of coronary lesions, and guide the strategies for percutaneous coronary intervention.

In vivo comparison between cardiac allograft vasculopathy and native atherosclerosis using near-infrared spectroscopy and intravascular ultrasound

AIMS

The aim was to compare cardiac allograft vasculopathy to native atherosclerosis by near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS).

METHODS AND RESULTS

Twenty-seven atherosclerotic (non-transplant) patients and 28 heart transplant recipients undergoing routine surveillance coronary angiography underwent NIRS-IVUS imaging of the left anterior descending coronary artery. In each proximal, middle, and distal coronary artery segment, the maxLCBI4mm [4-mm long segment with maximum lipid core burden index (LCBI)] and corresponding IVUS parameters were compared. MaxLCBI4mm was significantly greater among atherosclerotic patients than the transplant patients in both proximal and middle coronary artery segments, but not in the distal segment. There was a positive linear correlation between maxLCBI4mm and maximum plaque burden in both groups, but atherosclerotic patients demonstrated a smaller maxLCBI4mm than transplant recipients among segments with plaque burden <40%. Among segments with a maximum plaque burden ≥40%, native-atherosclerosis patients had a greater maxLCBI4mm compared with transplant patients (P = 0.015). Calcification was present in 72.9% of native atherosclerosis and 14.7% of transplant segments (P< 0.001). Among the 165 analysed segments, prevalence of lipid-rich plaque (LRP) with superficial attenuation (30.9 vs. 1.2%, P < 0.001) or calcified LRP (13.6 vs. 2.4%, P = 0.03) was significantly greater in native atherosclerosis compared with transplant patients. Conversely, the proportion of segments with non-LRP (46.4 vs. 11.1%, P < 0.001) was higher in transplant patients.

CONCLUSION

NIRS-IVUS imaging demonstrated early and accelerated lipid accumulation with smaller plaque burden and less calcium in patients after heart transplant when compared with patients with native atherosclerosis.

Techniques and best practices for optical coherence tomography: a practical manual for interventional cardiologists

Optical coherence tomography (OCT) is a novel intracoronary imaging modality that utilizes near-infrared light to provide information regarding lesion length and severity, vessel lumen diameter, plaque morphology, as well as the opportunity for stent procedure guidance and follow-up. While analogous to intravascular ultrasound (IVUS), the specific imaging properties, including significantly higher resolution, and technical specifications of OCT offer the ability for intracoronary diagnostic and interventional procedure guidance roles that require a thorough understanding of the technology. We provide coronary interventionalist's a user's guide to OCT, focusing on techniques and approaches to optimize imaging, with a focus on efficiency, safety and strategies for effective imaging.

Long-term prognostic impact of the attenuated plaque in patients with acute coronary syndrome

Several intravascular ultrasound studies have reported that culprit lesion-attenuated plaque (AP) is related to slow flow/no reflow after percutaneous coronary intervention (PCI). Long-term prognostic impact of the AP is unknown. The aim of this study was to investigate acute and long-term clinical impact of the AP in patients with acute coronary syndrome (ACS). A total of 110 ACS patients who underwent successful PCI were enrolled. Acute and long-term clinical outcomes were compared between patients with AP (AP group: n = 73) and those without AP (non-AP group: n = 37). Long-term cardiac event was defined as a composite of death and ACS. Baseline characteristics in 2 groups were similar. AP was associated with higher TIMI frame count immediately after the first balloon inflation. After thrombectomy and intracoronary drug administration, final TIMI frame count became similar between AP and non-AP group. Although AP was associated with higher incidence of fatal arrhythmia during hospitalization, in-hospital mortality did not differ between the 2 groups. During follow-up (median 6.2 years), cardiac event-free survival did not differ between the 2 groups. Despite the initial unfavorable effect on coronary reflow, presence of AP did not affect acute as well as long-term clinical outcome in patients with ACS.

Optical coherence tomography-based predictors for creatine kinase-myocardial band elevation after elective percutaneous coronary intervention for in-stent restenosis

OBJECTIVES

We evaluated whether morphological characteristics of neointimal tissue of in-stent restenosis (ISR) lesions assessed by optical coherence tomography (OCT) affect periprocedural elevation of creatine kinase-myocardial band (CK-MB).

BACKGROUND

The impact of neointimal characteristics of ISR lesions on periprocedural myocardial injury has not been sufficiently investigated.

METHODS

A total of 125 patients with ISR lesions underwent elective percutaneous coronary intervention (PCI) and pre-PCI OCT examination. Measurements of CK-MB were performed upon hospitalization, before PCI, and every 8 hr for 24 hr after PCI. CK-MB elevation was defined as levels above the 99th percentile of the upper reference limit. Neoatherosclerosis was defined as neointima with lipid or calcification.

RESULTS

Post-PCI CK-MB elevation was observed in 20 (16.0%) patients. The maximum length of consecutive cross-sections with neoatherosclerosis on the longitudinal axis of the stent was significantly larger in patients with post-PCI CK-MB elevation than in those without [8.8 mm (1.5-10.4) vs. 0.0 mm (0.0-1.0), P < 0.001], and thin-cap fibroatheroma (TCFA) were more frequently observed at the site of minimal lumen cross-sectional area in patients with post-PCI CK-MB elevation (55.0% vs. 1.9%, P < 0.001). Multivariate analysis revealed that the maximum length of segments with neoatherosclerosis [odds ratio (OR), 1.463; 95% confidence interval (CI), 1.090-1.962; P = 0.011] and TCFA (OR, 14.328; 95% CI, 1.118-183.628; P = 0.041) were independent predictors for post-PCI CK-MB elevation.

CONCLUSIONS

A greater axial length of neoatherosclerosis and the presence of TCFA at the most stenotic site were significantly associated with post-PCI CK-MB elevation in ISR lesions.

Intravascular ultrasound analysis to determine the relationship between high-density lipoprotein cholesterol and lesion characteristics in patients with coronary artery disease

OBJECTIVES

This study utilized grayscale intravascular ultrasound (IVUS) to explore the relationship between high-density lipoprotein cholesterol (HDL-C) levels and culprit lesion characteristics in patients with coronary artery disease.

BACKGROUND

Low HDL-C is associated with an increased risk of cardiovascular events. Previous IVUS studies have suggested a significant association between lesion characteristics and cardiovascular events.

METHODS

According to HDL-C levels, 120 patients who underwent IVUS for native, de novo coronary lesions before any intervention were divided into a low HDL-C group (<40 mg/dL, n = 60) and a high HDL-C group (≥40 mg/dL, n = 60). Quantitative and qualitative IVUS analyses were performed to compare lesion characteristics.

RESULTS

Quantitative IVUS measurements showed no significant differences between the 2 groups. HDL-C level was not significantly correlated with remodeling index (r = 0.03, P = 0.78). However, attenuated plaque was more frequent in the low HDL-C group (48.3% vs. 28.3%, P = 0.02) and a greater percentage of attenuated plaque was found in this group (32.5 ± 21.3% vs. 21.0 ± 11.0%, P = 0.02). Moreover, when categorized into 4 groups according to HDL-C levels, the proportion of attenuated plaque (64.7% in group with <30 mg/dL, 41.9% in group with 30-39 mg/dL, 36.4% in group with 40-59 mg/dL, and 6.3% in group with ≥60 mg/dL; P = 0.001 for trend) was significantly different among groups. On multivariate analysis, only HDL-C and male gender were independently associated with the presence of attenuated plaque at the culprit lesions.

CONCLUSIONS

Patients with low levels of HDL-C may be at increased risk of having a higher incidence of attenuated plaques.

Clinical utility of intravascular imaging and physiology in coronary artery disease

Intravascular imaging and physiology techniques and technologies are moving beyond the framework of research to inform clinical decision making. Currently available technologies and techniques include fractional flow reserve; grayscale intravascular ultrasound (IVUS); IVUS radiofrequency tissue characterization; optical coherence tomography, the light analogue of IVUS; and near-infrared spectroscopy that detects lipid within the vessel wall and that has recently been combined with grayscale IVUS in a single catheter as the first combined imaging device. These tools can be used to answer questions that occur during daily practice, including: Is this stenosis significant? Where is the culprit lesion? Is this a vulnerable plaque? What is the likelihood of distal embolization or periprocedural myocardial infarction during stent implantation? How do I optimize acute stent results? Why did thrombosis or restenosis occur in this stent? One of the legacies of coronary angiography is to presume that one technique will answer all of these questions; however, that often has been proved inaccurate in contemporary practice.

Spontaneous and procedural plaque embolisation in native coronary arteries: pathophysiology, diagnosis, and prevention

The detachment of atherothrombotic material from the atherosclerotic coronary plaque and downstream embolisation is an underrecognized phenomenon and it causes different degrees of impairment of the coronary microcirculation. During treatment of obstructive atherosclerotic plaque by percutaneous coronary intervention (PCI) distal embolisation (DE) is considered to be inevitable and it is associated with potential clinical and prognostic implications. This review aims to assess the main aspects of both spontaneous and procedural DE, analyze their different pathophysiology, provide specific insights on the main diagnostic tools for their identification, and finally focus on the main strategies for their treatment and prevention.

Evolution of intravascular assessment of coronary anatomy and physiology: from ultrasound imaging to optical and flow assessment

The fact that coronary angiography has limitations in terms of precise estimation and progression of atherosclerosis has been partially overcome during the last years by the use of new techniques. Catheter-based invasive modalities are of a profound clinical importance in regard to accurate assessment of coronary anatomy and physiology and the choice of the appropriate treatment strategy for each patient. Also their potential in clinical investigation projects is of great interest. This current review summarizes the basic principles of these methodologies and evidently highlights not only their use in clinical practice but also their contribution in clinical outcomes.