Intravascular ultrasound predictors for edge restenosis after newer generation drug-eluting stent implantation

Optimal Percutaneous Treatment Approach to Unprotected Ostial Left Anterior Descending Artery Disease: A Meta-Analysis and Systematic Review

BACKGROUND

The optimal management strategy for significant unprotected ostial left anterior descending artery (LAD) disease remains undefined. Merits of the two most common percutaneous approaches are considered in this quantitative synthesis.

METHOD

A meta-analysis was performed to compare ostial stenting (OS) and crossover stenting (CS) in the treatment of unprotected ostial LAD stenosis. The primary outcome is the disparity in target lesion revascularisation (TLR). The Mantel-Haenszel method was employed with random effect model, chosen a priori to account for heterogeneity among the included studies.

RESULTS

Seven studies comprising 1,181 patients were included in the analyses. Of these, 482 (40.8%) patients underwent CS. Overall, there was a statistically significant trend in favour of CS (odds ratio 0.51, 95% confidence interval 0.30-0.86, p=0.01) with respect to the rate of TLR at follow-up. This remained true when TLR involving the left circumflex artery (LCx) was considered, even when there was a greater need for unintended intervention to the LCx during the index procedure (odds ratio 6.68, 95% confidence interval: 1.69-26.49, p=0.007). Final kissing balloon inflation may reduce the need for acute LCx intervention. Imaging guidance appeared to improve clinical outcomes irrespective of approach chosen.

CONCLUSIONS

In the percutaneous management of unprotected ostial LAD disease, CS into the left main coronary artery (LMCA) appeared to reduce future TLR. Integration of intracoronary imaging was pivotal to procedural success. The higher incidence of unintended LCx intervention in the CS arm may be mitigated by routine final kissing balloon inflation, although the long-term implication of this remains unclear. In the absence of randomised trials, clinicians' discretion remains critical.

The role of optical coherence tomography in guiding percutaneous coronary interventions: is left main the final challenge?

Left main (LM) coronary artery disease is a high-risk lesion subset, with important prognostic implications for the patients. Recent advances in the field of interventional cardiology have narrowed the gap between surgical and percutaneous approach of this complex lesion setting. However, the rate of repeat revascularization remains higher in the case of percutaneous coronary intervention (PCI) on long-term follow-up. As such, the need for better stent optimization strategies has led to the development of intravascular imaging techniques, represented mainly by intravascular ultrasound (IVUS) and optical coherence tomography (OCT). These techniques are both able to provide excellent pre- and post-PCI guidance. While IVUS is an established modality in optimizing LM PCI, and is recommended by international revascularization guidelines, data and experience on the use of OCT are still limited. This review paper deeply analyzes the current role of OCT imaging in the setting of LM disease, particularly focusing on its utility in assessing plaque morphology and distribution, vessel dimensions and proper stent sizing, analyzing mechanisms of stent failure such as malapposition and underexpansion, guiding bifurcation stenting, as well as offering a direct comparison with IVUS in this critical clinical scenario, based on the most recent available data.

Physiology- or Imaging-Guided Strategies for Intermediate Coronary Stenosis

Importance

Treatment strategies for intermediate coronary lesions guided by fractional flow reserve (FFR) and intravascular ultrasonography (IVUS) have shown comparable outcomes. Identifying low-risk deferred vessels to ensure the safe deferral of percutaneous coronary intervention (PCI) and high-risk revascularized vessels that necessitate thorough follow-up can help determine optimal treatment strategies.

Objectives

To investigate outcomes according to treatment types and FFR and IVUS parameters after FFR- or IVUS-guided treatment.

Design, Setting, and Participants

This cohort study included patients with intermediate coronary stenosis from the Fractional Flow Reserve and Intravascular Ultrasound-Guided Intervention Strategy for Clinical Outcomes in Patients With Intermediate Stenosis (FLAVOUR) trial, an investigator-initiated, prospective, open-label, multicenter randomized clinical trial that assigned patients into an IVUS-guided strategy (which recommended PCI for minimum lumen area [MLA] ≤3 mm2 or 3 mm2 to 4 mm2 with plaque burden [PB] ≥70%) or an FFR-guided strategy (which recommended PCI for FFR ≤0.80). Data were analyzed from November to December 2022.

Exposures

FFR or IVUS parameters within the deferred and revascularized vessels.

Main Outcomes and Measures

The primary outcome was target vessel failure (TVF), a composite of cardiac death, target vessel myocardial infarction, and revascularization at 2 years.

Results

A total of 1619 patients (mean [SD] age, 65.1 [9.6] years; 1137 [70.2%] male) with 1753 vessels were included in analysis. In 950 vessels for which revascularization was deferred, incidence of TVF was comparable between IVUS and FFR groups (3.8% vs 4.1%; P = .72). Vessels with FFR greater than 0.92 in the FFR group and MLA greater than 4.5 mm2 or PB of 58% or less in the IVUS group were identified as low-risk deferred vessels, with a decreased risk of TVF (hazard ratio [HR], 0.25 [95% CI, 0.09-0.71]; P = .009). In 803 revascularized vessels, the incidence of TVF was comparable between IVUS and FFR groups (3.6% vs 3.7%; P = .95), which was similar in the revascularized vessels undergoing PCI optimization (4.2% vs 2.5%; P = .31). Vessels with post-PCI FFR of 0.80 or less in the FFR group or minimum stent area of 6.0 mm2 or less or with PB at stent edge greater than 58% in the IVUS group had an increased risk for TVF (HR, 7.20 [95% CI, 3.20-16.21]; P < .001).

Conclusions and Relevance

In this cohort study of patients with intermediate coronary stenosis, FFR- and IVUS-guided strategies showed comparable outcomes in both deferred and revascularized vessels. Binary FFR and IVUS parameters could further define low-risk deferred vessels and high-risk revascularized vessels.

Clinical impact of OCT-derived suboptimal stent implantation parameters and definitions

AIMS

Despite growing evidence supporting the clinical utility of optical coherence tomography (OCT) guidance during percutaneous coronary interventions (PCIs), there is no common agreement as to the optimal stent implantation parameters that enhance clinical outcome.

METHODS AND RESULTS

We retrospectively examined the predictive accuracy of suboptimal stent implantation definitions proposed from the CLI-OPCI II, ILUMIEN-IV OPTIMAL PCI, and FORZA studies for the long-term risk of device-oriented cardiovascular events (DoCE) in the population of large all-comers CLI-OPCI project. A total of 1020 patients undergoing OCT-guided drug-eluting stent implantation in the CLI-OPCI registry with a median follow-up of 809 (quartiles 414-1376) days constituted the study population. According to CLI-OPCI II, ILUMIEN-IV OPTIMAL PCI, and FORZA criteria, the incidence of suboptimal stent implantation was 31.8%, 58.1%, and 57.8%, respectively. By multivariable Cox analysis, suboptimal stent implantation criteria from the CLI-OPCI II [hazard ratio 2.75 (95% confidence interval 1.88-4.02), P < 0.001] and ILUMIEN-IV OPTIMAL PCI [1.79 (1.18-2.71), P = 0.006] studies, but not FORZA trial [1.11 (0.75-1.63), P = 0.597], were predictive of DoCE. At long-term follow-up, stent edge disease with minimum lumen area <4.5 mm2 [8.17 (5.32-12.53), P < 0.001], stent edge dissection [2.38 (1.33-4.27), P = 0.004], and minimum stent area <4.5 mm2 [1.68 (1.13-2.51), P = 0.011] were the main OCT predictors of DoCE.

CONCLUSION

The clinical utility of OCT-guided PCI might depend on the metrics adopted to define suboptimal stent implantation. Uncovered disease at the stent border, stent edge dissection, and minimum stent area <4.5 mm2 were the strongest OCT associates of stent failure.

Target Lesion Revascularization After Intravascular Ultrasound-Guided Percutaneous Coronary Intervention

BACKGROUND

Several stent expansion criteria derived from the intravascular ultrasound (IVUS) evaluation have been proposed to predict future clinical outcomes, but optimal stent expansion criteria as a guide during percutaneous coronary intervention (PCI) are still controversial. There are no studies evaluating the utility of stent expansion criteria along with the clinical and procedural factors in predicting target lesion revascularization (TLR) after contemporary IVUS-guided PCI.

METHODS

OPTIVUS-Complex PCI study (Optimal Intravascular Ultrasound Guided Complex Percutaneous Coronary Intervention) multivessel cohort was a prospective multicenter study enrolling 961 patients undergoing multivessel PCI including left anterior descending coronary artery using IVUS with an intention to meet the prespecified criteria for optimal stent expansion. We compared several stent expansion criteria (minimum stent area [MSA], MSA/distal or average reference lumen area, MSA/distal or average reference vessel area, OPTIVUS criteria, IVUS-XPL [Impact of Intravascular Ultrasound Guidance on Outcomes of Xience Prime Stents in Long Lesions] criteria, ULTIMATE [Intravascular Ultrasound Guided Drug Eluting Stents Implantation in "All-Comers" Coronary Lesions] criteria, and modified MUSIC [Multicenter Ultrasound Stenting in Coronaries Study] criteria) as well as clinical, angiographic, and procedural characteristics between lesions with and without TLR.

RESULTS

Among 1957 lesions, the cumulative 1-year incidence of lesion-based TLR was 1.6% (30 lesions). Hemodialysis, treatment of proximal left anterior descending coronary artery lesions, calcified lesions, small proximal reference lumen area, and small MSA had univariate associations with TLR, while all of the stent expansion criteria except for MSA were not associated with TLR. The independent risk factors of TLR were calcified lesions (hazard ratio, 2.34 [95% CI, 1.03-5.32]; P=0.04) and small proximal reference lumen area (Tertile 1: hazard ratio, 7.01 [95% CI, 1.45-33.93]; P=0.02; and Tertile 2: hazard ratio, 5.40 [95% CI, 1.17-24.90]; P=0.03).

CONCLUSIONS

In contemporary IVUS-guided PCI practice, the 1-year incidence of TLR was very low. MSA, but not other stent expansion criteria, had univariate association with TLR. Independent risk factors of TLR were calcified lesions and small proximal reference lumen area, although the findings should be interpreted with caution due to small number of TLR events, limited lesion complexity, and short duration of follow-up.

Management of failed stenting of the unprotected left main coronary artery

Percutaneous coronary intervention (PCI) is increasingly accepted as treatment for unprotected left main coronary artery (ULMCA) disease especially in those patients who are unsuitable for cardiac surgery. Treatment of any stent failure is associated with increased complexity and worse clinical outcomes when compared with de novo lesion revascularization. Intracoronary imaging has provided new insight into mechanisms of stent failure and treatment options have developed considerably over the last decade. There is paucity of evidence on the management strategy for stent failure in the specific setting of ULMCA. Treating any left main with PCI requires careful consideration and consequently treatment of failed stents in ULMCA is complex and provides unique challenges. Consequently, we provide an overview of ULMCA stent failure, proposing a tailored algorithm to guide best management and decision in daily clinical practice, with a special focus on intracoronary imaging characterization of causal mechanisms and specific technical and procedural considerations.

Intravascular Imaging During Percutaneous Coronary Intervention: JACC State-of-the-Art Review

Coronary angiography has historically served as the gold standard for diagnosis of coronary artery disease and guidance of percutaneous coronary intervention (PCI). Adjunctive use of contemporary intravascular imaging (IVI) technologies has emerged as a complement to conventional angiography-to further characterize plaque morphology and optimize the performance of PCI. IVI has utility for preintervention lesion and vessel assessment, periprocedural guidance of lesion preparation and stent deployment, and postintervention assessment of optimal endpoints and exclusion of complications. The role of IVI in reducing major adverse cardiac events in complex lesion subsets is emerging, and further studies evaluating broader use are underway or in development. This paper provides an overview of currently available IVI technologies, reviews data supporting their utilization for PCI guidance and optimization across a variety of lesion subsets, proposes best practices, and advocates for broader use of these technologies as a part of contemporary practice.

Outcomes of Percutaneous Coronary Interventions for Long Diffuse Coronary Artery Disease with Extremely Small Diameter

BACKGROUND

The optimal percutaneous coronary intervention (PCI) strategy and clinical outcomes of long lesions with an extremely small residual lumen remain unclear. This study aimed to assess the efficacy of a modified stenting strategy for diffuse coronary artery disease (CAD) with an extremely small distal residual lumen.

METHODS

736 Patients who received PCI using second-generation drug-eluting stents (DES) ≥38 mm long were retrospectively included and categorized into an extremely small distal vessel (ESDV) group (≤2.0 mm) and a non-ESDV group (>2.0 mm) according to the maximal luminal diameter of the distal vessel (dsD_Max). A modified stenting technique was applied by landing an oversized DES in the distal segment with the largest luminal diameter and maintaining the distal stent edge partially expanded.

RESULTS

The mean dsD_Max and stent lengths were 1.7 ± 0.3 mm and 62.6 ± 18.1 mm in the ESDV group and 2.7 ± 0.5 mm and 59.1 ± 16.0 mm in non-ESDV groups, respectively. The acute procedural success rate was high in both the ESDV and non-ESDV groups (95.8% and 96.5%, p = 0.70) with rare distal dissection (0.3% and 0.5%, p = 1.00). The target vessel failure (TVF) rate was 16.3% in the ESDV group and 12.1% in the non-ESDV group at a median follow-up of 65 months without significant differences after propensity score matching.

CONCLUSIONS

PCI using contemporary DES with this modified stenting technique is effective and safe for diffuse CAD with extremely small distal vessels.

Intravascular Imaging for Guiding In-Stent Restenosis and Stent Thrombosis Therapy

Advances in stent technology and the design of endovascular devices with thinner struts, anti-inflammatory and antithrombotic polymers, and better drug kinetics have enhanced the safety and efficacy of the second-generation drug-eluting stents and broadened their use in the therapy of high-risk patients and complex anatomies. However, despite these developments, in-stent restenosis and stent thrombosis remain the Achilles' heel of percutaneous coronary intervention, with their cumulative incidence reaching up to 10% at 5 years following percutaneous coronary intervention. The treatment of stent failure poses challenges and is associated with a worse prognosis than conventional percutaneous coronary intervention. Several studies have recently highlighted the value of intravascular imaging in identifying causes of stent failure, underscored its role in treatment planning, and registries have shown that its use may be associated with better clinical outcomes. The present review aims to summarize the evidence in the field; it discusses the value of intravascular imaging in identifying the mechanisms of in-stent restenosis and stent thrombosis in assessing the morphological characteristics of neointima tissue that appears to determine long-term outcomes in evaluating procedural results, and presents the findings of studies supporting its value in guiding therapy in stent failure.

Intravascular imaging in coronary stent restenosis: Prevention, characterization, and management

Despite the introduction of drug-eluting stents to combat the neointimal hyperplasia that occurred after BMS implantation, in-stent restenosis is still encountered in a significant number of patients, particularly as increasingly complex lesions are tackled by percutaneous coronary intervention. Many biological and mechanical factors interplay to produce restenosis, some of which are avoidable. Intravascular imaging provided unique insights into various forms of stent-related mechanical issues that contribute to this phenomenon. From a practical perspective, intravascular imaging can therefore help to optimize the stenting procedure to avert these issues. Moreover, once the problem of restenosis eventuates, imaging can guide the management by tackling the underlying identified mechanism. Finally, it can be used to evaluate the re-intervention results. Nevertheless, with the emergence of different treatment options, more evidence is needed to define patient/lesion-specific characteristics that may help to tailor treatment selection in a way that improves clinical outcomes.

Procedure-Related Differences and Clinical Outcomes in Patients Treated with Percutaneous Coronary Intervention Assisted by Optical Coherence Tomography between New and Earlier Generation Software (Ultreon™ 1.0 Software vs. AptiVue™ Software)

(1) Introduction: Optical coherence tomography (OCT) intravascular imaging facilitates percutaneous coronary intervention (PCI). Software for OCT is being constantly improved, including the latest version Ultreon™ 1.0 Software (U) (Abbott Vascular, Santa Clara, CA, USA). In the current analysis, we aim to compare processing results, procedural indices as well as clinical outcomes in patients treated via PCI. This was conducted using earlier generation OCT imaging software versions (non-U) and the newest available one on the market (U). (2) Methods: The study comprised 95 subsequent and not selected patients (55 processed with U and 40 non-U). The non-U processings were transferred for evaluation by U software, while the comparison of OCT parameters, selected clinical and procedural indices was performed between groups. We further assessed clinical outcomes during the follow-up period, i.e., major adverse cardiovascular events (MACE) and predictors of stent expansion. (3) Results: We did not detect any differences in general features between either of the assessed groups at baseline. Non-U software was more often used for bare-metal stenting (p = 0.004), while PCIs in the U group demanded a greater number of stents (p = 0.03). The distal reference of external elastic lamina (EEL) diameter was greater in the non-U group (p = 0.02) with no concurrent differences in minimal (p = 0.27) and maximal (p = 0.31) stent diameter. It was also observed that MACE was more frequently observed in the non-U group (p = 0.01). Neither univariable (estimate: 0.407, 95%CI: (−3.182) − 3.998, p = 0.82) nor multivariable (estimate: 2.29, 95%CI: (−4.207) − 8.788, p = 0.5) analyses demonstrated a relationship between the type of software and stent expansion. (4) Conclusions: Improvement in the software for image acquisition and processing of OCT is not related to stent expansion. The EEL diameter is preferably used to select the distal stent diameter in newer software.

Survivals of Angiography-Guided Percutaneous Coronary Intervention and Proportion of Intracoronary Imaging at Population Level: The Imaging Paradox

Background

There is a significant disparity between randomized controlled trials and observational studies with respect to any mortality benefit with intracoronary imaging during the percutaneous coronary intervention (PCI). This raises a suspicion that the imaging paradox, in which some operators may become over reliant on imaging and less proficient with angiography-guided PCI, might exist.

Method

This was a retrospective cohort study from 14 hospitals under the Hospital Authority of Hong Kong between January 1, 2010 and December 31, 2017. Participants were patients who underwent first-ever PCI. The association between mortality risks of patients undergoing angiography-guided PCI and three tertiles (low, medium, and high) of the proportion of PCI done under intracoronary imaging guidance at a population level (background imaging rate), were evaluated after confounder adjustment by multivariable logistic regression.

Results

In an adjusted analysis of 11,816 patients undergoing angiography-guided PCI, the risks of all-cause mortality for those were higher in the high-tertile group compared with the low-tertile group (OR, 1.45, 95% CI, 1.10–1.92, P = 0.008), the risks of cardiovascular mortality were higher in the high-tertile group compared with the low-tertile group (OR, 1.51, 95% CI, 1.08–2.13, P = 0.017). The results were consistent with multiple sensitivity analyses. Threshold analysis suggested that the mortality risks of angiography-guided PCI were increased when the proportion of imaging-guided PCI exceeded approximately 50%.

Conclusions

The risks of the all-cause mortality and cardiovascular mortality were higher for patients undergoing angiography-guided PCI in practices with a higher background imaging rate.

One-year outcomes of novel BioMime Morph tapered stent in long and multiple coronary artery lesions

OBJECTIVE

Even with the immense progress achieved in the field of percutaneous coronary interventions (PCIs), treatment of diffuse long atherosclerotic coronary artery disease continues to remain a challenge for durable outcomes. The downstream reduction in diameter along the lesion length of a coronary artery may compel the cardiologist to use either 2 overlapping stents of different diameters or a single long stent leading to stent-vessel mismatch at the edges. Recently, Meril Life Sciences Pvt. Ltd., India, has introduced a long-tapered sirolimus-eluting stent (SES) system, BioMime Morph, which conforms to the normal tapered geometry of coronary arteries along with adequate lesion coverage. In this study, we aimed to provide real world experience regarding the safety and efficacy of the BioMime Morph SES over a follow-up of one year.

METHODS

This was a single center, retrospective study involving 172 participants who underwent PCI with the BioMime Morph SES. Mean length of the target lesion was 34.4±10.4 mm, and mean stent length was 53.2±8.7 mm. The most frequent revascularized vessel was the left anterior descending artery (LAD) in 97 lesions (54.4%).

RESULTS

Major adverse cardiac events (MACE) (defined as a composite of target vessel myocardial infarction, target lesion revascularization, and death due to a cardiac cause) at 1, 6, and 12 months were seen in 4 (2.3%), 7 (4.0%), and 8 (4.7%) patients, respectively. Overall, 5 cardiac deaths and 2 definite stent thrombosis were observed in the study.

CONCLUSION

The study suggests that the novel BioMime Morph SES is an effective and a safe option for PCI in the treatment of long diffuse atherosclerotic lesions.

Improving PCI Outcomes Using Postprocedural Physiology and Intravascular Imaging

Although clinical outcomes after percutaneous coronary intervention (PCI) are improving, the long-term risk for target vessel failure remains concerning. Although the application of intravascular imaging and physiological indexes significantly improves outcomes, their routine use in practice remains limited. Nevertheless, merely using these modalities is not enough, and to truly improve patient outcomes, optimal intravascular dimensions with minimal vascular injury should be targeted. When assessing post-PCI results using either type of physiological or imaging technology, a broad spectrum of stent- and vessel-related anomalies can be expected. As not all of these issues warrant treatment, a profound knowledge of what to expect and how to recognize and when to treat these intraluminal problems is needed. Additionally, promising new modalities such as angiography-derived coronary physiology and hybrid imaging catheters are becoming available. The authors provide an overview of the currently available tools and techniques to define suboptimal PCI and when to apply these technologies to improve outcomes.

Clinical outcomes of post-stent intravascular ultrasound examination for chronic total occlusion intervention with drug-eluting stents

BACKGROUND

Few studies have evaluated intravascular ultrasound (IVUS) use in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

AIMS

In CTO-PCI, we aimed to (1) evaluate the clinical benefits of performing post-stent IVUS in preventing adverse clinical events, and (2) identify IVUS parameters and cut-off values for prediction of target lesion revascularisation (TLR)/reocclusion.

METHODS

A total of 1,077 patients with 1,077 CTO lesions treated with drug-eluting stents (DES) were included. Clinical outcomes during a median follow-up of 6.3 years were compared between subjects with and those without post-stent IVUS using the inverse probability weighting method.

RESULTS

Of 1,077 patients, post-stent IVUS was performed in 838 (77.8%) cases while in the remaining 239 (22.2%) cases it was not. In the weighted population, the risk of TLR/reocclusion was significantly lower in subjects with post-stent IVUS (9.6% vs 18.9%, hazard ratio [HR] 0.54, 95% confidence interval [CI]: 0.34-0.86, p=0.01), compared with those without post-stent IVUS. Cox regression analysis showed that minimal stent area (MSA) measured by IVUS was the only parameter independently associated with TLR/reocclusion (HR 0.78, 95% CI: 0.64-0.95; p=0.01) and the optimal MSA cut-off value was 4.9 mm2 for prediction of TLR/reocclusion (area under the curve=0.632, p=0.001).

CONCLUSIONS

In CTO-PCI with DES, post-stent IVUS evaluation was associated with a lower risk of TLR/reocclusion. The final MSA was independently associated with TLR/reocclusion with a cut-off value of 4.9 mm2.

Effect of Hinge Motion on Stent Edge-Related Restenosis After Right Coronary Artery Treatment in the Current Drug-Eluting Stent Era

BACKGROUND

Stent edge-related restenosis (SER) remains a potential limitation of drug-eluting stent (DES). Hinge motion at the stent edge could lead to mechanical stress and contribute to incidents of SER. We investigated the effect of hinge motion on SER after implantation of current-generation DES in the right coronary artery (RCA), where excessive vessel movement is commonly observed.Methods and Results:Of 647 consecutive lesions in the RCA treated with second-generation or later DESs, 426 with follow-up angiography were included in this study. Intravascular imaging analysis was performed for 584 stent edges and reference segments. Binary restenosis occurred in 42 lesions (9.9%), and 55% were SERs. The hinge angle was significantly larger in the SER group than in the other restenosis or the no-restenosis group (17.9° vs. 11.6° and 10.6°, respectively; P<0.001). Lesions with an excessive hinge angle (>11.5°) had an increased rate of target lesion revascularization (19.1% vs. 7.2%; P<0.001) during the median follow-up period of 1,578 days. In per-edge analysis, hinge angle and residual plaque burden were independent predictors of SER. The coexistence of excessive hinge motion and residual plaque burden had a synergistic effect on stenotic progression in quantitative angiographic analysis (P_interaction<0.001) at follow-up angiography.

CONCLUSIONS

Substantial stress determined by angulation at a stent edge and its interaction with residual plaque can be considered as one plausible mechanism for SER.

Zero contrast optical coherence tomography-guided percutaneous coronary intervention in patients with non-ST segment elevation myocardial infarction and chronic kidney disease

OBJECTIVES

To investigate a strategy for ultra-low volume contrast percutaneous coronary intervention (PCI) with the aims of preserving renal function and observing the 90-day clinical endpoint in patients with non-ST-elevated myocardial infarction (non-STEMI) and chronic kidney disease (CKD).

BACKGROUND

The feasibility, safety, and clinical utility of PCI with ultra-low radio-contrast medium in patients with non-STEMI and CKD are unknown.

METHODS

A total of 29 patients with non-STEMI and CKD (estimated glomerular filtration rate [eGFR] of ≤60 ml/min/1.73 m² ) were included. Ultra-low volume contrast PCI was performed after minimal contrast coronary angiography using zero contrast optical coherence tomography (OCT) guidance. Pre- and post-PCI angiographic measurements were performed using quantitative flow ratio (QFR) for pre-perfusion assessment and verifying improvement.

RESULTS

The median creatinine level was 2.1 (inter-quartile range 1.8-3.3), and mean eGFR was 48 ± 8 ml/min/1.73 m² pre-PCI. During the PCI procedure, OCT revealed 15 (52%) cases of abnormalities post-dilation. There was no significant change in the creatinine level and eGFR in the short- or long-term, and no major adverse events were observed.

CONCLUSION

In non-STEMI patients with high-risk CKD who require revascularization, QFR and no contrast OCT-guided ultra-low contrast PCI may be performed safely without major adverse events.

Intravascular ultrasound predictors of long-term outcomes following ABSORB bioresorbable scaffold implantation: A pooled analysis of the ABSORB III and ABSORB Japan trials

BACKGROUND

The long-term prognostic impact of IVUS findings following Absorb BVS implantation remains uncertain. This study aimed to identify the IVUS predictors of long-term clinical outcomes following ABSORB bioresorbable vascular scaffold (BVS) implantation from the pooled IVUS substudy cohorts of the ABSORB III and Japan trials.

METHODS

A total of 298 lesions in 286 patients were enrolled with 2:1 randomization to ABSORB BVS vs. cobalt-chromium everolimus-eluting stents. This sub-analysis included 168 lesions of 160 patients in the Absorb arm whose post-procedural quantitative IVUS were available. The primary endpoint of this analysis was device-oriented composite endpoint (DOCE) of target lesion failure, including cardiac death, target vessel-related myocardial infarction, or ischemia-driven target lesion revascularization. The median follow-up duration was 4.9 [3.1-5.0] years.

RESULTS

During follow-up, DOCE occurred in 10.1% of lesions treated with Absorb BVS. Among several post-procedural IVUS indices associated with DOCE, non-uniform device expansion (defined as uniformity index = minimum / maximum device area) (hazard ratio 0.47 per 0.1 increase [95%CI 0.28 to 0.77]; p = 0.003) and residual reference plaque burden (hazard ratio 4.01 per 10% increase [95%CI 1.50 to 10.77]; p = 0.006) were identified as independent predictors of DOCE by Cox multivariable analysis.

CONCLUSIONS

Nonuniform device expansion and substantial untreated residual plaque in reference segments were associated with long-term adverse events following BVS implantation. Baseline imaging to identify the appropriate device landing zone and procedural imaging to achieve uniform device expansion if possible (e.g. through post-dilatation) may improve clinical outcomes of BVS implantation.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01751906 (ABSORB III); NCT01844284 (ABSORB Japan).

Comparison of intravascular ultrasound-guided with angiography-guided double kissing crush stenting for patients with complex coronary bifurcation lesions: Rationale and design of a prospective, randomized, and multicenter DKCRUSH VIII trial

BACKGROUND

Double kissing (DK) crush approach for patients with coronary bifurcation lesions, particularly localized at distal left main or lesions with increased complexity, is associated with significant reduction in clinical events when compared with provisional stenting. Recently, randomized clinical trial has demonstrated the net clinical benefits by intravascular ultrasound (IVUS)-guided implantation of drug-eluting stent in all-comers. However, the improvement in clinical outcome after DK crush treatment guided by IVUS over angiography guidance for patients with complex bifurcation lesions have never been studied in a randomized fashion.

TRIAL DESIGN

DKCRUSH VIII study is a prospective, multicenter, randomized controlled trial designed to assess superiority of IVUS-guided vs angiography-guided DK crush stenting in patients with complex bifurcation lesions according to DEFINITION criteria. A total of 556 patients with complex bifurcation lesions will be randomly (1:1 of ratio) assigned to IVUS-guided or angiography-guided DK crush stenting group. The primary end point is the rate of 12-month target vessel failure, including cardiac death, target vessel myocardial infarction, or clinically driven target vessel revascularization. The secondary end points consist of the individual component of primary end point, all-cause death, myocardial infarction, and in-stent restenosis. The safety end point is the incidence of definite or probable stent thrombosis. An angiographic follow-up will be performed for all patients at 13 months and clinical follow-up will be continued annually until 3 years after the index procedure.

CONCLUSIONS

DKCRUSH VIII trial is the first study designed to evaluate the differences in efficacy and safety between IVUS-guided and angiography-guided DK crush stenting in patients with complex true bifurcation lesions. This study will also provide IVUS-derived criteria to define optimal DK crush stenting for bifurcation lesions at higher complexity.

Multi-modality intravascular imaging for guiding coronary intervention and assessing coronary atheroma: the Novasight Hybrid IVUS-OCT system

Intravascular imaging has evolved alongside interventional cardiology as an adjunctive tool for assessing plaque pathology and for guiding and optimising percutaneous coronary intervention (PCI) in challenging lesions. The two modalities which have dominated the field are intravascular ultrasound (IVUS), which relies on sound waves and optical coherence tomography (OCT), relying on light waves. These approaches however have limited efficacy in assessing plaque morphology and vulnerability that are essential for guiding PCI in complex lesions and identifying patient at risk that will benefit from emerging therapies targeting plaque evolution. These limitations are complementary and, in this context, it has been recognised and demonstrated in multi-modality studies that the concurrent use of IVUS and OCT can help overcome these deficits enabling a more complete and accurate plaque assessment. The Conavi Novasight Hybrid IVUS-OCT catheter is the first commercially available device that is capable of invasive clinical coronary assessment with simultaneously acquired and co-registered IVUS and OCT imaging. It represents a significant evolution in the field and is expected to have broad application in clinical practice and research. In this review article we present the limitations of standalone intravascular imaging techniques, summarise the data supporting the value of multimodality imaging in clinical practice and research, describe the Novasight Hybrid IVUS-OCT system and highlight the potential utility of this technology in coronary intervention and in the study of atherosclerosis.

Optical Coherence Tomography Versus Intravascular Ultrasound and Angiography to Guide Percutaneous Coronary Interventions: The iSIGHT Randomized Trial

[Figure: see text].

Optical Coherence Tomography of the Coronary Arteries

Intravascular imaging, particularly optical coherence tomography, has brought significant improvement in diagnostic and therapeutical approaches to coronary artery disease and has offered superior high-resolution visualization of coronary arteries. The ability to obtain images of intramural and transmural coronary structures allows the study of the process of atherosclerosis, effect of therapies, mechanism of acute coronary syndrome and stent failure, and performance of new devices and enables the interventional cardiologist to optimize the effect of percutaneous coronary intervention. In this review, we provide the summary of the latest published data on clinical use of optical coherence tomography as well as practical algorithm for optical coherence tomography-guided percutaneous coronary intervention for daily interventional practice.

Impact of intravascular ultrasound on chronic total occlusion percutaneous revascularization

AIM

We sought to investigate the impact of IVUS use on chronic total occlusion (CTO) PCI using data from a contemporary registry of consecutive patients and applying a propensity score matching analysis.

METHODS AND RESULTS

We evaluated 514 successful CTO-PCIs, median age: 67 years (IQR: 58-73), 83.5% males. IVUS-guided PCI was performed in 184 (35.8%) of cases. After using 1:1 propensity matching score analysis, two groups of 182 patients each (IVUS-guided vs. angiography-guided CTO-PCI group) were produced to form the study population. In the IVUS-guided group the median maximum stent diameter was larger and the median total stented segment was longer compared to the angiography-guided group [(3.5 mm, IQR: 3.0-4.0 vs. 3.2 mm, IQR: 3.0-3.5, p < 0.001) and (60.0 mm, IQR: 38.0-91.3 vs. 38.0 mm, IQR: 32.0-70.5, p < 0.001), respectively]. In the IVUS-guided group, retrograde recanalization was more frequently encountered compared to the angiography-guided PCI group (30.2% vs. 20.9%, p = 0.04). Procedural time was significantly longer in the IVUS-guided group, without any difference in fluoroscopy time, radiation dose and contrast volume. Multivariate linear regression analysis showed that IVUS use was the strongest independent factor associated with larger maximum diameter stents (p < 0.001) and a strong independent predictor for total stented segment length during CTO-PCI (p < 0.001). Up to 8 years follow-up, there was no difference in the incidence of the composite endpoint of all-cause death, cardiac death, myocardial infarction and target vessel revascularization between the IVUS-guided PCI and the angiography-guided PCI groups (hazard ratio: 13.7% vs. 15.9%, respectively, log-rank: p = 0.67, median follow-up time: 49.0 months, IQR: 33.0-67.0).

CONCLUSIONS

Use of IVUS in CTO-PCI was associated with larger stent diameter and longer stented segments. Despite more frequent use of IVUS in retrograde CTO-PCI, there was no difference in long-term adverse events between IVUS and angiography CTO-PCI groups; nevertheless, the study was not powered to assess clinical outcomes.

Mechanisms of drug-eluting stent restenosis

Drug-eluting stents (DES) were developed to overcome in-stent restenosis (ISR), which has long been considered the main complication limiting the long-term efficacy of coronary stenting. New-generation DES which composed of advanced stent design with and without specific biocompatible polymer contributes a reduction of the incidence of ISR to rate ranging from 5 to 10%. The precise reasons of DES restenosis are still controversial and not fully understood. Angiographic and coronary images at the index procedure, systemic status of patients, medications, and intracoronary imaging at ISR site are all considered to find the possible mechanisms of DES restenosis. Multiple biological, genetic, mechanical, and technical factors might intricately contribute to DES restenosis. Biological and genetic factors of ISR are not able to be sufficiently modified by the current medical approaches. Tailored treatments avoiding mechanical and technical factors of ISR are required to reduce DES restenosis. Elucidation of DES restenosis leads to further improvement in the current DES system and finds the optimal approach to treat DES restenosis. The possible mechanisms of DES restenosis are discussed in this review.

Use of Intravascular Imaging in Patients With ST-Segment Elevation Acute Myocardial Infarction

BACKGROUND

The use and impact of intravascular imaging in ST-elevation myocardial infarction (STEMI) patients has received limited study.

METHODS

We queried the National Inpatient Sample database (NIS) between January 2016 and December 2017 to identify hospitalizations of STEMI patients who underwent percutaneous coronary intervention (PCI). We used a 1:2 propensity-score (PS) matched analysis to compare in-hospital outcomes in patients with vs. without use of intravascular imaging. We conducted a multivariable regression analysis to identify variables independently associated with in-hospital mortality.

RESULTS

We identified 252,970 weighted discharges of PCI in STEMI patients, 5.5% of which included intravascular imaging. Patients in whom intravascular imaging was used were more likely to have acute stent thrombosis (4.7% vs. 1.4%, p < 0.001) and present with anterior STEMI (48.1% vs. 39.1%, p < 0.001). After PS matching (intravascular imaging n = 14,015, no intravascular imaging n = 28,025), the use of intravascular imaging was associated with lower in-hospital mortality (3.6% vs. 4.8%, p = 0.010). The risk of in-hospital complications and discharge to a facility (nursing facility or short-term acute hospital) was similar between both groups before and after PS matching. The use of intravascular imaging was associated with a higher index hospitalization cost [$25,218 vs. $20,515, p < 0.001]. On multivariable analysis, intravascular imaging was independently associated with lower in-hospital mortality [OR 0.735 (95% CI 0.662-0.816), p < 0.001].

CONCLUSION

Intravascular imaging was used in 5.5% of PCIs in STEMI patients and was independently associated with lower in-hospital mortality and higher index hospitalization cost.

Comparison of serial optical coherence tomography imaging following aggressive stent expansion technique: insight from the MECHANISM study

To compare early vascular healing following cobalt-chromium everolimus-eluting stent (CoCr-EES) implantation between groups with or without aggressive stent expansion in patients treated by CoCr-EES for stable coronary artery disease (CAD). Seventy-one stable CAD lesions underwent CoCr-EES implantation and analysis of serial optical coherence tomography (OCT) images obtained post-procedure and at early-term (1- or 3-month) follow-up. The endpoints of this study were neointimal thickness at the time of 1- or 3-month OCT and presence and healing of stent edge dissection. Aggressive stent expansion was defined as a lesion complying with ILUMIEN III sizing protocol; that is, external elastic lamina (EEL) diameter minus maximum balloon diameter ≤ 0.25 mm.  Comparing groups with and without aggressive stent expansion, median neointimal thickness at 1 and 3 months after CoCr-EES implantation was similar (1 month: 0.031 mm vs. 0.041 mm, respectively, p = 0.27; 3 months: 0.036 mm vs. 0.040 mm, respectively, p = 0.84). Regarding stent edge findings, the presence of any stent edge dissection immediately after percutaneous coronary intervention was also similar between the groups (25% vs. 15%, respectively; p = 0.30) and most stent edge dissections resolved completely within 3 months, regardless of location or dissection severity. After 1 year, no clinically driven target lesion revascularization or stent thrombosis was observed in either cohort. Even after aggressive stent expansion, early neointimal proliferation appeared modest with CoCr-EES implantation, and most stent edge dissections had resolved by 3 months. These findings may support the feasibility of EEL-based sizing by pre-stenting OCT.

When to use intravascular ultrasound or optical coherence tomography during percutaneous coronary intervention?

Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are intravascular imaging technologies widely used in the cardiac catheterization laboratory. The impact of these modalities for optimizing the acute and longer-term clinical impact following percutaneous coronary intervention (PCI) is supported by a wealth of clinical evidence. Intravascular imaging provides unique information for enhanced lesion preparation, optimal stent sizing, recognizing post PCI complications, and the etiology of stent failure. This review compares and contrasts the key aspects of these imaging modalities during PCI.

Intracoronary near-infrared spectroscopy-role and clinical applications

Intracoronary near-infrared spectroscopy (NIRS) has been developed and validated for the detection of lipid-rich plaque in the coronary arteries. A combined NIRS and intravascular ultrasound catheter is currently in clinical use and has an emerging role in evaluating plaques both before and after percutaneous coronary intervention. NIRS has recently been shown to positively identify both vulnerable patients and vulnerable plaques. This review focuses on the principles and image interpretation of intracoronary NIRS, as well as its clinical applications, limitations, and future directions.

Efficacy of coronary imaging on bifurcation intervention

During the coronary bifurcation intervention procedure, imaging including intravascular ultrasound and optical coherence tomography is essential to provide precise anatomy of the lesion and morphological information. This consensus document between the Korean Bifurcation Club and the Japanese Bifurcation Club summarizes practical guidelines and current evidences on lesion assessment, device selection, procedural guidance, and the optimization of bifurcation intervention by the imaging.

Impact of real-time angiographic co-registered optical coherence tomography on percutaneous coronary intervention: the OPTICO-integration II trial

Aims

Longitudinal geographic mismatch (LGM) as well as edge dissections are associated with an increased risk of adverse events after percutaneous coronary intervention (PCI). Recently, a novel system of real-time optical coherence tomography (OCT) with angiographic co-registration (ACR) became available and allows matched integration of cross-sectional OCT images to angiography. The OPTICO-integration II trial sought to assess the impact of ACR for PCI planning on the risk of LGM and edge dissections.

Methods

A total of 84 patients were prospectively randomized to ACR-guided PCI, OCT-guided PCI (without co-registration), and angiography-guided PCI. Primary endpoint was a composite of major edge dissection and/or LGM as assessed by post-PCI OCT.

Results

The primary endpoint was significantly reduced in ACR-guided PCI (4.2%) as compared to OCT-guided PCI (19.1%; p = 0.03) and angiography-guided PCI (25.5%; p < 0.01). Rates of LGM were 4.2%, 17.0%, and 22.9% in the ACR-guided PCI, in the OCT-guided PCI, and the angiography-guided PCI groups, respectively (ACR vs. OCT p = 0.04; ACR vs. angiography p = 0.04). The number of major edge dissections was low and without significant differences among the study groups (0% vs. 2.1% vs. 4.3%).

Conclusion

This study for the first time demonstrates superiority of ACR-guided PCI over OCT- and angiography-guided PCI in reducing the composite endpoint of major edge dissection and LGM, which was meanly driven by a reduction of LGM.

Graphical abstract

Intravascular Ultrasound-guided Versus Angiography-guided Percutaneous Coronary Intervention: Evidence from Observational Studies and Randomized Controlled Trials

Coronary angiography has been considered the gold standard for the diagnosis of coronary artery disease and guidance of percutaneous coronary intervention (PCI). However, 2D-projection angiography cannot completely reflect the 3D coronary lumen. Intravascular ultrasound (IVUS) can overcome a number of limitations of coronary angiography by providing more information about the dimensions of the vessel lumen, plaque characteristics, stent deployment, and the mechanisms of device failure. Growing data from observational studies and randomized controlled trials have confirmed the clinical benefit of IVUS guidance during PCI. This article summarizes the evidence regarding IVUS guidance to highlight its advantages and to support the use of IVUS during PCI.

The angiography-guided spot versus entire stenting in patients with long coronary lesions trial: Study design and rationale for a randomized controlled trial protocol

Background

/Purpose: Long-stenting, even with a second-generation drug-eluting stent (DES), is an independent predictor of restenosis and stent thrombosis in patients with long coronary lesions. Spot-stenting, i.e., selective stenting of only the most severe stenotic segments of a long lesion, may be an alternative to a DES. The purpose of this study is to compare the one-year clinical outcomes of patients with spot versus entire stenting in long coronary lesions using a second-generation DES.

Method

This study is a randomized, prospective, multi-center trial comparing long-term clinical outcomes of angiography-guided spot versus entire stenting in patients with long coronary lesions (≥25 mm in length). The primary endpoint is target vessel failure (TVF) at 12 months, a composite of cardiac death, target vessel-related myocardial infarction, and target vessel revascularization (TVR). A total of 470 patients are enrolled for this study according to sample size calculations. This study will be conducted to evaluate the non-inferiority of spot stenting compared to entire stenting with zotarolimus-eluting stents (ZES).

Results

This study is designed to evaluate the clinical impact of spot-stenting with ZESs for TVF due to possible edge restenosis or non-target lesion revascularization. Theoretically, spot-stenting may decrease the risk of TVR and the extent of endothelial dysfunction.

Conclusion

This SPOT trial will provide clinical insight into spot-stenting with a current second-generation DES as a new strategy for long coronary lesions.

Optimization of Percutaneous Coronary Intervention Using Optical Coherence Tomography

Compared to the luminogram obtained by angiography, intravascular modalities produce cross-sectional images of coronary arteries with a far greater spatial resolution. It is capable of accurately determining the vessel size and plaque morphology. It also eliminates some disadvantages such as contrast streaming, foreshortening, vessel overlap, and angle dependency inherent to angiography. Currently, the development of its system and the visualization of coronary arteries has shown significant advancement. Of those, optical coherence tomography (OCT) makes it possible to obtain high-resolution images of intraluminal and transmural coronary structures leading to navigation of the treatment strategy before and after stent implantations. The aim of this review is to summarize the published data on the clinical utility of OCT, focusing on the use of OCT in interventional cardiology practice to optimize percutaneous coronary intervention.

Prediction of coronary thin-cap fibroatheroma by intravascular ultrasound-based machine learning

BACKGROUND AND AIMS

Although grayscale intravascular ultrasound (IVUS) is commonly used for assessing coronary lesion morphology and optimizing stent implantation, detection of vulnerable plaques by IVUS remains challenging. We aimed to develop machine learning (ML) models for predicting optical coherence tomography-derived thin-cap fibroatheromas (OCT-TCFAs).

METHODS

In 517 patients with angina, 414 and 103 coronary lesions were randomized into training vs. test sets. Each of the IVUS-OCT co-registered frames (including 32,807 for training and 8101 for test) was labeled according to the presence vs. absence of OCT-TCFA. Among 1449 computed IVUS features based on two-dimensional geometry and texture, 17 features were finally selected and used in supervised ML with artificial neural network (ANN), support vector machine (SVM), and naïve Bayes.

RESULTS

IVUS sections with (vs. without) OCT-TCFA showed a larger plaque burden, and a smaller and eccentric lumen. TCFA-containing sections were characterized by increased ratios of variance, entropy, and kurtosis; reduced ratio of homogeneity within the superficial to the deeper plaque; and decreased smoothness within the fibrous cap. In addition, OCT-TCFA was associated with low ratios of gamma-beta, Nakagami-μ and Nakagami-ω, and a high ratio of Rayleigh-b within the superficial to the deeper region. With a 5-fold cross-validation, the averaged accuracies were 81 ± 5% for ANN (area under the curve [AUC] = 0.80 ± 0.08), 77 ± 4% for SVM (AUC = 0.74 ± 0.05), and 78 ± 2% for naïve Bayes (AUC = 0.77 ± 0.04) for predicting OCT-TCFA. In the test set, ANN and naïve Bayes showed the overall accuracies of >80%.

CONCLUSIONS

Supervised ML algorithms with computed IVUS features predicted the presence of OCT-TCFA. This data-driven approach may help clinicians in recognizing high-risk coronary lesions.

Personalized Assessment of the Coronary Atherosclerotic Arteries by Intravascular Ultrasound Imaging: Hunting the Vulnerable Plaque

The term "vulnerable plaque" is commonly used to refer to an atherosclerotic plaque that is prone to rupture and the formation of thrombosis, which can lead to several cardiovascular and cerebrovascular events. Coronary artery atherosclerosis has a wide variety of different phenotypes among patients who may have a substantially variable risk for plaque rupture and cardiovascular events. Mounting evidence has proposed three distinctive histopathological mechanisms: plaque rupture, plaque erosion and calcified nodules. Studies have demonstrated the characteristics of plaques with high vulnerability such as the presence of a thin fibrous cap, a necrotic lipid-rich core, abundant infiltrating macrophages and neovascularization. However, traditional coronary angiographic imaging fails to determine plaque vulnerability features, and its ability to individualize treatment strategies is limited. In recent decades, catheter-based intravascular ultrasound imaging (IVUS) modalities have been developed to identify vulnerable plaques and ultimately vulnerable patients. The aim is to individualize prediction, prevention and treatment of acute coronary events based on the identification of specific features of high-risk atherosclerotic plaques, and to identify the most appropriate interventional procedures for their treatment. In this context, the aim of this review is to discuss how personalized assessment of coronary atherosclerotic arteries can be achieved by intravascular ultrasound imaging focusing on vulnerable plaque detection.

Rational and design of the European randomized Optical Coherence Tomography Optimized Bifurcation Event Reduction Trial (OCTOBER)

Background

Percutaneous coronary intervention in complex bifurcation lesions is prone to suboptimal implantation results and is associated with increased risk of subsequent clinical events. Angiographic ambiguity is high during bifurcation stenting, but it is unknown if procedural guidance by intravascular optical coherence tomography (OCT) improves clinical outcome.

Methods and Design

OCTOBER is a randomized, investigator-initiated, multicenter trial aimed to show superiority of OCT-guided stent implantation compared to standard angiographic-guided implantation in bifurcation lesions. The primary outcome measure is a 2-year composite end point of cardiac death, target lesion myocardial infarction, and ischemia-driven target lesion revascularization. The calculated sample size is 1,200 patients in total, and allocation is 1:1. Eligible patients have stable or unstable angina pectoris or stabilized non–ST elevation myocardial infarction, and a coronary bifurcation lesion with significant main vessel stenosis and more than 50 % stenosis in a side branch with a reference diameter ≥2.5mm. Treatment is performed by the provisional side branch stenting technique or 2-stent techniques, and the systematic OCT guiding protocol is aimed to evaluate (1) plaque preparation, (2) lesion length, (3) segmental reference sizes, (4) lesion coverage, (5) stent expansion, (6) malapposition, (7) wire positions, and (8) ostial results.

Implications

A positive outcome of the OCTOBER trial may establish OCT as a routine tool for optimization of complex percutaneous coronary intervention, whereas a negative result would indicate that OCT remains a tool for ad hoc evaluation in selected cases.

IVUS-Guided Versus OCT-Guided Coronary Stent Implantation: A Critical Appraisal

Procedural guidance with intravascular ultrasound (IVUS) imaging improves the clinical outcomes of patients undergoing percutaneous coronary intervention (PCI) by: 1) informing the necessity for lesion preparation; 2) directing appropriate stent sizing to maximize the final stent area and minimize geographic miss; 3) selecting the optimal stent length to cover residual disease adjacent to the lesion, thus minimizing geographic miss; 4) guiding optimal stent expansion; 5) identifying acute complications (edge dissection, stent malapposition, tissue protrusion); and 6) clarifying the mechanism of late stent failure (stent thrombosis, neointimal hyperplasia, stent underexpansion or fracture, or neoatherosclerosis). Optical coherence tomography (OCT) provides similar information to IVUS (with some important differences), also potentially improving acute and long-term patient outcomes compared to angiography-guided PCI. The purpose of this review is to describe the similarities and differences between IVUS and OCT technologies, and to highlight the evidence supporting their utility to improve PCI outcomes.

Intravascular ultrasound in the evaluation and treatment of left main coronary artery disease: a consensus statement from the European Bifurcation Club

Interventional cardiology and coronary stent insertion have an increasing role in the optimal management of left main coronary artery (LMCA) stenosis. Assessing the extent of obstructive disease of the LMCA by angiography alone can be challenging. However, in contrast to the two-dimensional, shadow graphic nature of coronary angiography, intravascular ultrasound (IVUS) is an accurate tomographic technique for assessing both the coronary lumen and the vessel wall characteristics. Consequently, it is a particularly useful technique in imaging the LMCA before, during and after intervention. The European Bifurcation Club (EBC) recommends the use of IVUS during most LMCA interventions. The purpose of this consensus document is to review the available IVUS data on LMCA disease evaluation and treatment. It is a practical guide to show "how and when" to use the imaging modality. It is hoped that a standardisation of the practical approach to imaging may allow consolidation of learning and, ultimately, improve patient outcomes.

Algorithmic Approach for Optical Coherence Tomography-Guided Stent Implantation During Percutaneous Coronary Intervention

Intravascular imaging plays a key role in optimizing outcomes for percutaneous coronary intervention (PCI). Optical coherence tomography (OCT) utilizes a user-friendly interface and provides high-resolution images. OCT can be used as part of daily practice in all stages of a coronary intervention: baseline lesion assessment, stent selection, and stent optimization. Incorporating a standardized, algorithmic approach when using OCT allows for precision PCI.

Comparison of Fractional FLow Reserve And Intravascular ultrasound-guided Intervention Strategy for Clinical OUtcomes in Patients with InteRmediate Stenosis (FLAVOUR): Rationale and design of a randomized clinical trial

BACKGROUND

Coronary angiography has limitations in defining the ischemia-causing stenotic lesion, especially in cases with intermediate coronary stenosis. Fractional flow reserve (FFR) is a current standard method to define the presence of ischemia, and intravascular ultrasound (IVUS) is the most commonly used invasive imaging tool that can provide the lesion geometry and can provide the information on plaque vulnerability. The primary aim of this study is to compare the safety and efficacy of FFR-guided and IVUS-guided percutaneous coronary intervention (PCI) strategies in patients with intermediate coronary stenosis.

TRIAL DESIGN

Comparison of Fractional FLow Reserve And Intravascular ultrasound-guided Intervention Strategy for Clinical OUtcomes in Patients with InteRmediate Stenosis (FLAVOUR) trial is an international, multicenter, prospective, randomized clinical trial. A total of 1,700 consecutive patients with intermediate stenosis (40%-70% by visual estimation) in a major epicardial coronary artery will be randomized 1:1 to receive either FFR-guided or IVUS-guided PCI strategy. Patients will be treated with PCI according to the predefined criteria for revascularization; FFR ≤ 0.80 in the FFR-guided group and Minimal Lumen Area (MLA) ≤3 mm² (or 3 mm²<MLA ≤4 mm² and plaque burden >70%) in the IVUS-guided group. The primary end point is the patient-oriented composite outcome, which is a composite of all-cause death, myocardial infarction, and any repeat revascularization at 24months after randomization. We will test noninferiority of current standard FFR-guided PCI strategy compared with IVUS-guided decision for PCI and stent optimization strategy.

CONCLUSION

The FLAVOUR trial will compare the safety and efficacy of FFR- and IVUS-guided PCI strategies in patients with intermediate coronary stenosis. This study will provide an insight on optimal evaluation and treatment strategy for patients with intermediate coronary stenosis.