Impact of frequency-domain optical coherence tomography guidance for optimal coronary stent implantation in comparison with intravascular ultrasound guidance

Clinical Outcomes Following Optical Coherence Tomographic Versus Intravascular Ultrasound-Guided Percutaneous Coronary Intervention: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Optical coherence tomography (OCT) and intravascular ultrasound (IVUS) are adjunctive intracoronary imaging modalities used to optimize coronary stent implantation. However, the impact of OCT versus IVUS on clinical outcomes and periprocedural complications is unclear.

AIMS

To perform a meta-analysis of all vetted randomized controlled trials comparing OCT-guided versus IVUS-guided percutaneous coronary intervention.

METHODS

We queried MEDLINE, Cochrane Library, Scopus, and clinicalTrials.gov databases from their commencement to February 2024 for all randomized controlled trials that compared OCT-guided versus IVUS-guided percutaneous coronary interventions. The primary endpoint was major adverse periprocedural events (MAPE), a composite of stent thrombosis (ST), distal embolization (DE), and distal edge dissection (DED) at 30 days. The secondary endpoints included ST, DE, DED, major adverse cardiac events (MACE)-(a composite of cardiac death, target vessel myocardial infarction TVMI], and target vessel revascularization [TVR]), all-cause mortality, cardiac death, TVMI, TVR, and nonfatal stroke at 1 year. The odds ratio (OR) with a 95% confidence interval (CI) was analyzed using a random-effect model.

RESULTS

Seven randomized controlled trials were included in the analysis, and 4446 patients were enrolled. OCT was associated with lower MAPE (OR: 0.65, CI: 0.47-0.91, p = 0.01) compared to IVUS. ST, DE, and DED were similar between OCT and IVUS at 30 days. There were no significant differences in MACE (OR: 0.86, CI: 0.64-1.16, p = 0.32), all-cause mortality (OR: 0.83, CI: 0.42-1.66, p = 0.60), Cardiac death (OR:0.62, CI: 0.20-1.89, p = 0.40), TVMI (OR: 0.69, CI: 0.33-1.46, p = 0.33), TVR, (OR: 1.09, CI: 0.70-1.71, p = 0.70), and Nonfatal stroke (OR: 1.82, CI: 0.67-4.95, p = 0.24) 1 year following the index procedure.

CONCLUSION

Optical coherence tomographic-guided PCI was associated with lower MAPE, defined as a composite of ST, DE, and DED, compared to IVUS-guided PCI at 30 days of the index procedure. However, there was no difference in overall MACE, TVMI, TVR, and nonfatal stroke at 1 year.

Unlocking the Secrets of Acute Coronary Syndromes Using Intravascular Imaging: From Pathophysiology to Improving Outcomes

Acute coronary syndrome (ACS) represents the most severe manifestation of coronary artery disease. Intravascular imaging, both intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have played crucial roles for the impressive reduction in mortality of ACS. Intravascular imaging is useful for the detection of atherosclerotic mechanism (plaque rupture, calcified nodules, or plaque erosions) and for the evaluation of nonatherosclerotic and nonobstructive types of ACS. In addition, IVUS and OCT play a crucial role in the optimization of the PCI. The aim of the current review is to present the role of intravascular imaging in identifying the mechanisms of ACS and its prognostic role in future events, to review the current guidelines suggesting intravascular imaging use in ACS, to summarize its role in PCI in patients with ACS, and to compare IVUS and OCT.

Optical coherence tomography to guide percutaneous coronary intervention

Percutaneous coronary intervention (PCI) has been most commonly guided by coronary angiography. However, to overcome the inherent limitations of conventional coronary angiography, there has been an increasing interest in the adjunctive tools of intracoronary imaging for PCI guidance. Recently, optical coherence tomography (OCT) has garnered substantial attention as a valid intravascular imaging modality for guiding PCI. However, despite the unparalleled high-resolution imaging capability of OCT, which offers detailed anatomical information on coronary lesion morphology and PCI optimisation, its broad application in routine PCI practice remains limited. Several factors may have curtailed the widespread adoption of OCT-guided PCI in daily practice, including the transitional challenge from intravascular ultrasound (IVUS), the experienced skill required for image acquisition and interpretation, the lack of a uniform algorithm for OCT-guided PCI optimisation, and the limited clinical evidence. Herein, we provide an in-depth review of OCT-guided PCI, involving the technical aspects, optimal strategies for OCT-guided PCI, and the wide application of OCT-guided PCI in various anatomical subsets. Special attention is given to the latest clinical evidence from recent randomised clinical trials with respect to OCT-guided PCI.

Comparison of Long-Term Outcomes Between Intravascular Ultrasound-, Optical Coherence Tomography- and Angiography-Guided Stent Implantation: A Meta-Analysis

Intravascular ultrasonography (IVUS) and optical coherence tomography (OCT) guided percutaneous coronary interventions (PCI) are alternative techniques to angiography-guided (ANG-g) PCI in patients with coronary artery disease (CAD), especially for optimal stent deployment in coronary arteries. We conducted a network meta-analysis including studies comparing those three techniques. We searched databases for studies that compared IVUS, OCT, and ANG-g PCI in patients with CAD. Overall, 52 studies with 231,137 patients were included in this meta-analysis. ANG-g PCI had higher major adverse cardiovascular events (MACEs), all-cause death, cardiac death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis (ST) than IVUS-guided PCI. Of note, both OCT-guided and IVUS-guided PCI had similar outcomes. The frequency of MACEs, cardiac death, and MI were higher in ANG-g PCI than in OCT-guided PCI. The highest benefit was established with OCT for MACEs (P-score=.973), MI (P-score=.823), and cardiac death (P-score=.921) and with IVUS for all-cause death (P-score=.792), TLR (P -score=.865), and ST (P-score=.930). This network meta-analysis indicated that using OCT or IVUS for optimal stent implantation provides better outcomes in comparison with ANG-g in patients with CAD undergoing PCI.

Intravascular imaging-guided versus angiography-guided percutaneous coronary intervention: a systematic review and bayesian network meta-analysis of randomized controlled trials

BACKGROUND

Percutaneous coronary intervention (PCI) has become one of the most commonly performed interventional life-saving procedures worldwide. Intravascular Imaging (intravascular ultrasound (IVUS) and optical coherence tomography (OCT)) have initially evolved to guide PCI compared with angiography. However, this technology is not universally employed in all PCI procedures, and there is ongoing controversy regarding its additional benefits to patient outcomes. We aim to estimate the efficacy and safety of imaging modalities during PCI, allowing pre-, per, and post-intervention assessment of coronary vascularization.

METHODS

A systematic review and Bayesian network meta-analysis of randomized controlled trials (RCTs), which were retrieved from PubMed, WOS, SCOPUS, EMBASE, and CENTRAL through September 2023. We used R, version 4.2.0. Effect sizes will be presented as odds ratios with accompanying 95% credible intervals.

PROSPERO ID

CRD42024507821.

RESULTS

Our study, encompassing 36 RCTs with a total of 17,572 patients, revelead that compared to conventional angiography, IVUS significantly reduced the risk of major adverse cardiovascular events (MACE) (OR: 0.71 [95% CrI: 0.56 to 0.87]) but not OCT (OR: 0.91 [95% CrI: 0.62 to 1.39]), IVUS and OCT significantly reduced the risk of cardiac death (OR: 0.50 [95% CrI: 0.33 to 0.76]) and (OR: 0.55 [95% CrI: 0.31 to 0.98]), respectively, IVUS significantly reduced the risk of target vessel-related revascularization (OR: 0.60 [95% CrI: 0.48 to 0.75]) but not OCT (OR: 0.86 [95% CrI: 0.60 to 1.19]), IVUS and OCT significantly reduced the risk of stent thrombosis (OR: 0.50 [95% CrI: 0.28 to 0.92]) and (OR: 0.48 [95% CrI: 0.22 to 0.98]), respectively, IVUS significantly reduced the risk of re-stenosis (OR: 0.65 [95% CrI: 0.46 to 0.88]) but not OCT (OR: 0.55 [95% CrI: 0.15 to 1.99]), neither IVUS (OR: 0.97 [95% CrI: 0.71 to 1.38]) nor OCT (OR: 0.75 [95% CrI: 0.49 to 1.22]) were associated with statistically significant reductions in all-cause mortality, neither IVUS (OR: 0.70 [95% CrI: 0.45 to 1.32]) nor OCT (OR: 0.81 [95% CrI: 0.47 to 1.59]) were associated with statistically significant reductions in target vessel failure, neither IVUS (OR: 0.88 [95% CrI: 0.43 to 2.44]) nor OCT (OR: 0.81 [95% CrI: 0.37 to 2.04]) were associated with statistically significant reductions in target lesion failure, and neither IVUS (OR: 0.82 [95% CrI: 0.60 to 1.06]) nor OCT (OR: 0.84 [95% CrI: 0.59 to 1.19]) were associated with statistically significant reductions in myocardial infarction.

CONCLUSION

Intravascular imaging-guided, including IVUS and OCT, improved the postinterventional outcomes of PCI, notably suggesting their advantage over traditional angiography with no significant difference between IVUS and OCT.

Optical coherence tomography-guided versus angiography-guided percutaneous coronary intervention: A meta-analysis of randomized controlled trials

Background

Optical Coherence Tomography (OCT), a high-resolution imaging modality, guides stent implantation during percutaneous coronary intervention (PCI). However, OCT-guided PCI safety and efficacy data is limited.

Methods

MEDLINE, Embase, and Cochrane Central were searched for randomized controlled trials (RCTs) comparing OCT-guided PCI to Angiography-guided PCI from inception to August 2023. A random-effects model was used to pool risk ratios (RRs), mean differences (MDs), and 95% confidence intervals (CIs) for clinical endpoints.

Results

Our analysis included 5,139 patients from 11 studies. OCT-guided PCI resulted in a higher minimum stent area (MD = 0.35 [95 % CI, 0.21-0.49]; p < 0.00001), significantly reduced risk of cardiovascular mortality (RR = 0.56 [95 % CI, = 0.32-0.99]; p = 0.04), stent thrombosis (RR = 0.56 [95 % CI, 0.32-0.96]; p = 0.04), stent malapposition RR = 0.79 [95 % CI, 0.71-0.88]; p = < 0.0001) and major edge dissection (RR = 0.47 [95 % CI, 0.34-0.65]; p = <0.00001). However, no statistically significant difference was observed for all-cause mortality (RR = 0.71; p = 0.06), major adverse cardiovascular events (MACE) [RR = 0.80; p = 0.10], myocardial infarction (MI) [RR = 0.84; p = 0.16], target lesion revascularization (TLR) [RR = 0.94; p = 0.68], and target vessel revascularization (TVR) [RR = 0.91; p = 0.52].

Conclusion

OCT-guided PCI led to an increased MSA and decreased cardiovascular mortality, stent thrombosis, stent malapposition, and major edge dissection. The incidence of all-cause mortality, MACE, MI, TLR, and TVR remained comparable across the two groups.

Optical coherence tomography-guided vs. intravascular ultrasound-guided percutaneous coronary intervention: a systematic review and meta-analysis of randomized controlled trials

Background

Optical coherence tomography (OCT) and intravascular ultrasound (IVUS) are superior to coronary angiography for guiding percutaneous coronary intervention (PCI). However, whether one technique is superior to the other is inconclusive.

Methods

We searched PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov from inception to November 2023 for randomized controlled trials (RCTs) comparing OCT and IVUS in patients undergoing PCI. RevMan 5.4 was used to pool outcomes with risk ratio (RR) as the effect measure.

Results

Six RCTs (4,402 patients) were included in this meta-analysis. There was no significant difference between the OCT- and IVUS-guided PCI groups in the risk of major adverse cardiovascular events (RR 0.87, 95% CI: 0.65, 1.16; I2 = 0%) and cardiac mortality (RR 0.73, 95% CI: 0.24, 2.21; I2 = 0%). The results were consistent across the subgroups of the presence or absence of left main disease (P interaction >0.1). There were no significant differences between OCT and IVUS in the risk of target lesion revascularization (RR 0.78, 95% CI: 0.47, 1.30; I2 = 0%), target vessel revascularization (RR 1.06, 95% CI: 0.69, 1.62; I2 = 0%), target-vessel myocardial infarction (RR 0.79, 95% CI: 0.40, 1.53; I2 = 0%), stent thrombosis (RR 0.59, 95% CI: 0.12, 2.97; I2 = 0%), and all-cause mortality (RR 1.01, 95% CI: 0.53, 1.90; I2 = 0%).

Conclusions

Our meta-analysis demonstrated similar clinical outcomes in OCT- and IVUS-guided PCI. New large-scale multicenter RCTs with long-term follow-up are required to confirm or refute our findings and provide more reliable results.

Systematic Review Registration

PROSPERO, identifier, CRD42023486933.

Comparison of definitions of coronary artery reference sizes and effects on stent selection and evaluation of stent expansion

Accurate determination of coronary reference size is essential for optimal stent selection and evaluation of stent expansion during percutaneous coronary intervention (PCI). Several approaches for reference size estimation have been published with no universal agreement. The aim of this study was to investigate if potential differences in coronary reference size estimation lead to differences in stent and balloon selection and in detection of stent under expansion. Definitions for coronary reference size estimation, stent size selection, and stent expansion were identified in 17 randomized controlled trials. The identified methods were applied in a population of 32 clinical cases. Reference size estimates ranged up to 1.35mm, and indicated nominal stent size ranged up to 1.0 mm in the same case depending on method. Mean relative stent expansion ranged from 54±12% to mean 100±29% depending on the applied reference method. Choice of method for reference size estimation using intravascular imaging may influence stent selection and greatly affects evaluation of post-PCI stent expansion.

Utilization of intravascular imaging in elective non chronic total occlusion percutaneous intervention and chronic total occlusion percutaneous intervention: Trends in utilization and impact on in-hospital mortality

OBJECTIVES

The objectives of this retrospective study include outcomes associated with and without intravascular imaging in cases of elective single vessel (SV) CTO PCI and in non-CTO PCI.

METHOD

We explored the NIS database from October 1, 2015 to December 31, 2018 to identify 317,090 adult admissions with elective SV PCI. Admissions with STEMI and NSTEMI were excluded to identify elective cases only. Using the ICD 10 diagnosis code for CTO, we identified 33,345 admissions that underwent SV CTO PCI. We classified the remaining cases as SV non-CTO PCI.

RESULTS

Intravascular imaging was utilized in 2930 (8.8%) cases in CTO PCI group and 23,710 (8.3%) cases in non-CTO PCI groups. The utilization of intravascular imaging (IVUS/OCT) significantly increased in elective SV CTO PCI, 6.4%-11.2%, p-trend<0.001 and non-CTO PCI group, 7.3%-9.0%, p-trend<0.001. There was no significance difference in mortality with and without intravascular imaging (combined IVUS/OCT vs no IVUS/OCT: 1.5% vs 1.3%, p = 0.195) in the CTO PCI group. But, in non-CTO PCI admissions, there was a significantly lower in-hospital mortality when intravascular imaging was used (0.7% vs 0.8%, p = 0.003). The cost of hospitalization was significantly higher when intravascular imaging was used in elective single vessel CTO PCI admissions, combined IVUS/OCT vs no IVUS/OCT: $27,427 vs $21,452, p < 0.001 and non-CTO PCI admissions, combined IVUS/OCT vs no IVUS/OCT: $23,620 vs $20,272, p < 0.001.

CONCLUSIONS

In conclusion, despite the cost, intravascular imaging use decrease mortality in non-CTO PCI groups but there is no difference in mortality in CTO PCI groups.

Intravascular Lithotripsy for the Treatment of Severely Calcified Coronary Artery Disease: A DISRUPT CAD III Intravascular Ultrasound Substudy

BACKGROUND

Coronary intravascular lithotripsy (IVL) has emerged as a novel technique for the treatment of severely calcified coronary lesions. We evaluated the mechanism and efficacy of IVL in facilitating optimal stent implantation in heavily calcified coronary lesions using intravascular ultrasound (IVUS).

METHODS

Forty-six patients were initially enrolled as a part of the Disrupt CAD III study. Of these, 33 had pre-IVL, 24 had post-IVL, and 44 had post-stent IVUS evaluation. The final analysis was performed on 18 patients who had IVUS images interpretable at all three intervals. The primary endpoint was increase in minimum lumen area (MLA) from pre-IVL to post-IVL treatment to post-stenting.

RESULTS

Pre-IVL, MLA was 2.75 ± 0.84 mm2, percent area stenosis was 67.22 % ± 20.95 % with maximum calcium angle of 266.90° ± 78.30°, confirming severely calcified lesions. After IVL, MLA increased to 4.06 ± 1.41 mm2 (p = 0.0003), percent area stenosis decreased to 54.80 % ± 25.71 % (p = 0.0009), and maximum calcium angle decreased to 239.40° ± 76.73° (p = 0.003). There was a further increase in MLA to 6.84 ± 2.18 mm2 (p < 0.0001) and decrease in percent area stenosis to 30.33 % ± 35.08 % (p < 0.0001) post-stenting with minimum stent area of 6.99 ± 2.14 mm2. The success rate of stent delivery, implantation, and post-stent dilation was 100 % post-IVL.

CONCLUSION

In this first study evaluating the mechanism of IVL using IVUS, the primary endpoint of increase in MLA from pre-IVL to post-IVL treatment to post-stenting was successfully achieved. Our study showed that the use of IVL-assisted percutaneous coronary intervention is associated with improved vessel compliance, facilitating optimal stent implantation in de novo severely calcified lesions.

IVUS-guided versus OCT-guided PCI among patients presenting with acute coronary syndrome

BACKGROUND

Intravascular imaging modalities such as intravascular ultrasound (IVUS) and, more recently, optical coherence tomography (OCT) improved the visualization of coronary anatomy and plaque pathology. We aimed to compare the procedural and short-term outcomes between IVUS-guided and OCT-guided percutaneous coronary interventions (PCIs) in patients with acute coronary syndrome (ACS).

METHODS

In the present retrospective study, we reviewed the data of 50 patients who had IVUS-guided PCI and 50 patients who had OCT-guided PCI for ACS between January 2020 and June 2021. Intravascular imaging was done before and after stenting. Both groups were compared in terms of minimal luminal area (MLA), stent dimensions, final minimal stent area (MSA) and stent expansion as well as negative angiographic outcomes. Patients were followed for six months to record major adverse cardiac events (MACE).

RESULTS

The patients' mean age was 57 ± 13 years with male predominance (78%). The radiation time and dose were significantly higher among IVUS group. Pre-stenting MLA was significantly higher in IVUS group (2.63 mm vs. 2.22 mm in OCT, P = 0.013). Stent expansion was significantly higher among OCT group (97% vs. 93% in IVUS group, P = 0.001) with no significant difference between both groups regarding MSA [mm²] (8.88 ± 2.87 in IVUS vs. 8.1 ± 2.76 in OCT, P = 0.169). No significant difference between both groups was noted regarding contrast volume, edge dissection, tissue prolapse, and no reflow. The rates of six-month MACE were significantly higher in the IVUS group.

CONCLUSIONS

OCT-guided PCI in ACS is safe and is associated with similar MSA to that of IVUS-guided PCI. Future randomized trials are needed to confirm these findings.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention: Evidence and Clinical Trials

Intracoronary imaging is beneficial to optimize stent implantation and reduce the risk of stent-related complications. Optical coherence tomography (OCT) is an intravascular imaging modality that allows for detailed microstructural evaluation during the percutaneous coronary intervention (PCI). Recently, several large-scale registries, randomized trials, and meta-analyses have shown the superiority of OCT to angiography and noninferiority to IVUS with respect to both acute procedural results and mid-term clinical outcomes. This article summarizes the data supporting the application of OCT-guided PCI to several specific situations, introduces important evidence, and discusses the ongoing controversies and limitations of the current evidence base in the field of OCT-guided PCI.

Intravascular imaging modalities in coronary intervention: Insights from 3D-printed phantom coronary models

INTRODUCTION AND OBJECTIVES

Several studies comparing optical coherence tomography (OCT) and intravascular ultrasound (IVUS) have revealed that OCT consistently provides smaller area and diameter measurements. However, comparative assessment in clinical practice is difficult. Three-dimensional (3D) printing offers a unique opportunity to assess intravascular imaging modalities. We aim to compare intravascular imaging modalities using a 3D-printed coronary artery in a realistic simulator and to assess whether OCT underestimates intravascular dimensions, exploring potential corrections.

METHODS

A standard realistic left main anatomy with an ostial left anterior descending artery lesion was replicated using 3D printing. After provisional stenting and optimization, IVI was obtained. Modalities included 20 MHz digital IVUS, 60 MHz rotational IVUS (HD-IVUS) and OCT. We assessed luminal area and diameters at standard locations.

RESULTS

Considering all coregistered measurements, OCT significantly underestimated area, minimal diameter and maximal diameter measurements in comparison to IVUS and HD-IVUS (p<0.001). No significant differences were found between IVUS and HD-IVUS. A significant systematic dimensional error was found in OCT auto-calibration by comparing known reference diameter of guiding catheter (1.8 mm) to measured mean diameter (1.68 mm±0.04 mm). By applying a correction factor based on the reference guiding catheter area to OCT, the luminal areas and diameters became not significantly different compared to IVUS and HD-IVUS.

CONCLUSION

Our findings suggest that automatic spectral calibration method for OCT is inaccurate, with a systematic underestimation of luminal dimensions. When guiding catheter correction is applied the performance of OCT is significantly improved. These results may be clinically relevant and need to be validated.

Optical coherence tomography and coronary revascularization: from indication to procedural optimization

Angiography alone is the most commonly used imaging modality for guidance of percutaneous coronary interventions. Angiography is limited, however, by several factors, including that it only portrays a low resolution, two-dimensional outline of the lumen and does not inform on plaque composition and functional stenosis severity. Optical coherence tomography (OCT) is an intracoronary imaging technique that has superior spatial resolution compared to all other imaging modalities. High-resolution imaging of the vascular wall enables precise measurement of vessel wall and luminal dimensions, more accurately informing about the anatomic severity of epicardial stenoses, and also provides input for computational models to assess functional severity. The very high-resolution images also permit plaque characterization that may be informative for prognostication. Moreover, periprocedural imaging provides valuable information to guide lesion preparation, stent implantation and to evaluate acute stent complications for which iterative treatment might reduce the occurrence of major adverse stent events. As such, OCT represent a potential future all-in-one tool that provides the data necessary to establish the indications, procedural planning and optimization, and final evaluation of percutaneous coronary revascularization.

Network Meta-analysis of Trials Comparing Intravascular Ultrasound, Optical Coherence Tomography, and Angiography-Guided Technique for Drug-Eluting Stent Implantation

Background

The current advances in coronary imaging with the introduction of intravascular ultrasound (IVUS), and more recently, optical coherence tomography (OCT) have overcome the limitations of coronary angiography.

Objective

This study aimed to conduct a comprehensive network meta-analysis of randomized clinical trials to report clinical outcomes among patients undergoing drug-eluting stent (DES) implantation either by IVUS- or OCT-guided technique or angiography alone.

Methods

PubMed/MEDLINE and EMBASE databases were searched systematically for all relevant published randomized clinical trials from the inception of the respective database to October 15th, 2021. The outcomes of interest assessed in this meta-analysis were major adverse cardiac events, myocardial infarction, target vessel revascularization, all-cause mortality, and cardiovascular mortality. All the endpoints were expressed as odds ratio (OR) with 95% CI. The network diagrams were computed using the OR as an effective measure. All statistical analyses were carried out in R statistical software version 4.0.3.

Results

A total of 14 randomized clinical trials were included in our meta-analysis. In patient undergoing DES implantation, angiography alone was associated with higher odds of major adverse cardiac events (OR, 1.62; 95% CI, 1.17-2.24), target vessel revascularization (OR, 1.60; 95% CI, 1.21-2.13) and cardiovascular mortality (OR, 1.97; 95% CI, 1.25-3.11). However, OCT demonstrated similar odds of major adverse cardiac events, cardiovascular mortality, and target vessel revascularization compared with IVUS. The odds of myocardial infarction and all-cause mortality were similar among all the 3 groups.

Conclusions

Although angiography alone was associated with worse outcomes than IVUS in a patient undergoing DES implantation, no difference in outcome was noted between patients undergoing DES implantation with OCT compared with IVUS. Advanced intracoronary imaging use should be encouraged to prevent excess mortality and morbidity.

Optical coherence tomography versus angiography and intravascular ultrasound to guide coronary stent implantation: A systematic review and meta-analysis

BACKGROUND

Optical coherence tomography (OCT) is an adjunct to angiography-guided coronary stent placement. However, in the absence of dedicated, appropriately powered randomized controlled trials, the impact of OCT on clinical outcomes is unclear.

OBJECTIVE

To conduct a systematic review and meta-analysis of all available studies comparing OCT-guided versus angiography-guided and intravascular ultrasound (IVUS)-guided coronary stent implantation.

METHODS

MEDLINE and Cochrane Central were queried from their inception through July 2022 for all studies that sought to compare OCT-guided percutaneous coronary intervention (PCI) to angiography-guided and IVUS-guided PCI. The primary endpoint was minimal stent area (MSA) compared between modalities. Clinical endpoints of interest were all-cause and cardiovascular mortality, major adverse cardiovascular events (MACE), myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and stent thrombosis (ST). Risk ratios (RRs) and mean differences (MDs) with their corresponding 95% confidence intervals (CIs) were pooled using a random-effects model.

RESULTS

Thirteen studies (8 randomized control trials and 5 observational studies) enrolling 6312 participants were included. OCT was associated with a strong trend toward increased MSA compared to angiography (MD = 0.36, p = 0.06). OCT-guided PCI was also associated with a reduction in the incidence of all-cause mortality [RR = 0.59, 95% CI (0.35, 0.97), p = 0.04] and cardiovascular mortality [RR = 0.41, 95% CI (0.21, 0.80), p = 0.009] compared with angiography-guided PCI. Point estimates favored OCT relative to angiography in MACE [RR = 0.75, 95% CI (0.47, 1.20), p = 0.22] and MI [RR = 0.75, 95% CI (0.53, 1.07), p = 0.12]. No differences were detected in ST [RR = 0.71, 95% CI (0.21, 2.44), p = 0.58], TLR [RR = 0.71, 95% CI (0.17, 3.05), p = 0.65], or TVR rates [RR = 0.89, 95% CI (0.46, 1.73), p = 0.73]. Compared with IVUS guidance, OCT guidance was associated with a nonsignificant reduction in the MSA (MD = -0.16, p = 0.27). The rates of all-cause and cardiovascular mortality, MACE, MI, TLR, TVR, or ST were similar between OCT-guided and IVUS-guided PCI.

CONCLUSIONS

OCT-guided PCI was associated with reduced all-cause and cardiovascular mortality compared to angiography-guided PCI. These results should be considered hypothesis generating as the mechanisms for the improved outcomes were unclear as no differences were detected in the rates of TLR, TVR, or ST. OCT- and IVUS-guided PCI resulted in similar post-PCI outcomes.

Intravascular Imaging for Percutaneous Coronary Intervention Guidance and Optimization: The Evidence for Improved Patient Outcomes

As of this writing, there have been approximately 24 randomized controlled trial publications, 32 meta-analyses, and 85 registries comparing intravascular ultrasound (IVUS) or optical coherence tomography (OCT) versus angiography-guided drug-eluting stent implantation (or IVUS versus OCT guidance). Although in specific clinical scenarios IVUS or OCT may be preferred, in most drug-eluting stent implantation procedures, either intravascular ultrasound or OCT can be used safely, efficiently, effectively, and interchangeably and will improve patient outcomes compared with stent implantation procedures performed just with angiography guidance.

Comparison of Six Different Percutaneous Coronary Intervention Guidance Modalities

Background: New randomized trials and modalities in guiding percutaneous coronary intervention (PCI) have become available. Objective: We aimed to compare the clinical outcomes of coronary angiography (CAG), intravascular ultrasound (IVUS), optical coherence tomography (OCT), fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), and optical frequency domain imaging (OFDI)-guided PCI. Methods: A network meta-analysis was performed to compare different PCI guidance modalities. The clinical outcomes included major adverse cardiovascular events (MACE), all-cause death, myocardial infarction (MI), and target vessel/lesion revascularization (TVR/TLR). Odds ratio (OR) and corresponding 95% credible interval (CrI) were calculated. Results: Thirty-six randomized trials, including 19,042 patients, were included. In comparison with CAG, IVUS significantly reduced MACE (OR: 0.71; 95% CrI: 0.57 to 0.86) and TVR/TLR (OR: 0.53; 95% CrI: 0.43 to 0.66). MACE (OR: 1.44; 95% CrI: 1.02 to 2.08) and TVR/TLR (OR: 1.87; 95% CrI: 1.04 to 3.71) were significantly increased in the FFR group, compared with IVUS group. There were no significant differences in MACE or TVR/TLR among the left guidance modality comparisons. Differences in all-cause death or MI were not observed in any comparisons. Conclusions: IVUS could reduce MACE and TVR/TLR, compared with CAG or FFR. Therefore, IVUS may be the optimal modality in guiding PCI.

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.

Comparative Appraisal of Intravascular Ultrasound and Optical Coherence Tomography in Invasive Coronary Imaging: 2022 Update

Although coronary angiography has been well established as a standard modality for percutaneous coronary intervention guidance, recent developments in intravascular imaging techniques, such as intravascular ultrasound and optical coherence tomography, have become increasingly adopted, enabling direct detailed lesion visualization, including lesions beyond the scope of assessment using exclusively angiography. Intravascular imaging modalities have been reported to potentially improve both short- and long-term percutaneous intervention outcomes. This review aims to provide a comparative summary of recent advancements in research regarding the clinical applications and outcomes of intravascular ultrasound and optical coherence tomography.

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.

Clinical Outcomes Following Hemodynamic Parameter or Intravascular Imaging-Guided Percutaneous Coronary Intervention in the Era of Drug-Eluting Stents: An Updated Systematic Review and Bayesian Network Meta-Analysis of 28 Randomized Trials and 11,860 Patients

Background

Coronary angiography (CAG) is the standard imaging modality for guiding percutaneous coronary interventions (PCI). Intracoronary imaging techniques such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT), and hemodynamic parameter like fractional flow reserve (FFR) can overcome some limitations of CAG.

Objective

We sought to explore the clinical outcomes of different PCI guidance modalities in the era of drug-eluting stent (DES).

Methods

A network meta-analysis of 28 randomized trials and 11,860 patients undergoing different modalities-guided PCI in the era of DES was performed. Odds ratio (OR) with 95% credible interval (CrI) were calculated.

Results

In comparison with CAG, IVUS was associated with a significant reduction in major adverse cardiovascular events (MACE, OR: 0.60; 95% CrI: 0.46–0.79), cardiovascular death (OR: 0.46; 95% CrI: 0.20–0.94), target vessel/lesion revascularization (TVR/TLR, OR: 0.55; 95% CrI: 0.41–0.74), and a trend toward decreased risk of stent thrombosis (OR: 0.44; 95% CrI: 0.17 to 1.00). FFR/quantitative flow ratio (QFR) could significantly reduce stroke compared with CAG, IVUS, and OCT/optical frequency domain imaging (OFDI). However, myocardial infarction (MI), all-cause death, stent thrombosis, and any revascularization presented similar risks for different PCI guidance modalities.

Conclusion

In the era of DES, IVUS led to lower risks of MACE than CAG, which was mainly due to lower risks of cardiovascular death and TVR/TLR. A trend toward decreased risk of stent thrombosis was also observed with IVUS. Hemodynamic parameter (FFR/QFR)-guided PCI could significantly reduce the stroke risk compared with CAG, IVUS, and OCT/OFDI.

Systematic Review Registration

[https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42021291442].

Optical Coherence Tomography: An Eye Into the Coronary Artery

Optical coherence tomography (OCT) is slowly but surely gaining a foothold in the hands of interventional cardiologists. Intraluminal and transmural contents of the coronary arteries are no longer elusive to the cardiologist's probing eye. Although the graduation of an interventionalist in imaging techniques right from naked eye angiographies to ultrasound-based coronary sonographies to the modern light-based OCT has been slow, with the increasing regularity of complex coronary cases in practice, such a transition is inevitable. Although intravascular ultrasound (IVUS) due to its robust clinical data has been the preferred imaging modality in recent years, OCT provides a distinct upgrade over it in many imaging and procedural aspects. Better image resolution, accurate estimation of the calcified lesion, and better evaluation of acute and chronic stent failure are the distinct advantages of OCT over IVUS. Despite the obvious imaging advantages of OCT, its clinical impact remains subdued. However, upcoming newer trials and data have been encouraging for expanding the use of OCT to wider indications in clinical utility. During percutaneous coronary intervention (PCI), OCT provides the detailed information (dissection, tissue prolapse, thrombi, and incomplete stent apposition) required for optimal stent deployment, which is the key to successfully reducing the major adverse cardiovascular event (MACE) and stent-related morbidities. The increasing use of OCT in complex bifurcation stenting involving the left main (LM) is being studied. Also, the traditional pitfalls of OCT, such as additional contrast load for image acquisition and stenting involving the ostial and proximal LM, have also been overcome recently. In this review, we discuss the interpretation of OCT images and its clinical impact on the outcome of procedures along with current barriers to its use and newer paradigms in which OCT is starting to become a promising tool for the interventionalist and what can be expected for the immediate future in the imaging world.

Feasibility and Safety of Very-Low Contrast Combined Ringer's Solution in Optical Coherence Tomography Imaging

Background

Optical coherence tomography (OCT) is an important modality used in coronary intervention. However, OCT requires a high amount of contrast media, limiting its extensive application in clinical practice. This study compared OCT images of coronary lesions obtained using contrast media and very-low contrast combined Ringer's solution (VLCCR) in patients with acute coronary syndrome (ACS).

Methods

Thirty ACS patients with a total of 36 native lesions and stenoses from 70 to 90% were included in this study. Two kinds of flushing media (a contrast medium and VLCCR) were used in succession in a random order for OCT image pullback of each lesion. VLCCR method is using low volume contrast (4–5 ml) injected into the guiding catheter previously combination with injector infused Ringer's solution instead of pure contrast medium. The safety of procedure was evaluated by recording the patients ‘symptoms, changes of ECG, blood pressure and heart rate. OCT images were analyzed to determine the image clarity. Lumen area and diameter were also measured and the consistency between the two media was compared.

Results

OCT procedure using either contrast or VLCCR did not show any peri-procedural adverse events. There was no difference in changes of blood pressure and heart rate in both procedures, however, VLCCR procedure showed less procedure-related symptoms and ECG changes. We found that the percentage of clear image frame was equivalent between the contrast and VLCCR media (98.0 vs. 96.9%, P = 0.90). We also observed a high degree of similarity between the different lesion phenotypes of ACS for both media. There was a linear correlation of the phenotypes obtained with these two different methods, and a significant correlation was observed between measurements obtained with contrast and VLCCR without correction for the refractive index of VLCCR (correlation coefficients ranged between 0.829 and 0.948).

Conclusions

OCT imaging using VLCCR for blood clearance is feasible and safe and provides similar imaging quality compared to OCT imaging obtained using radiographic contrast media for ACS patients.

Outcomes of intravascular ultrasound versus optical coherence tomography guided percutaneous coronary angiography: A meta regression-based analysis

BACKGROUND

Studies comparing clinical outcomes with intravascular ultrasound (IVUS) versus optical coherence tomography (OCT) guidance for percutaneous coronary intervention (PCI) in patients presenting with coronary artery disease, including stable angina or acute coronary syndrome, are limited.

METHODS

We performed a detailed search of electronic databases (PubMed, Embase, and Cochrane) for randomized controlled trials and observational studies that compared cardiovascular outcomes of IVUS versus OCT. Data were aggregated for the primary outcome measure using the random-effects model as pooled risk ratio (RR). The primary outcome of interest was major adverse cardiac events (MACE), cardiac mortality, and all-cause mortality. Secondary outcomes included myocardial infarction (MI), stent thrombosis (ST), target lesion revascularization (TLR), and stroke.

RESULTS

A total of seven studies met the inclusion criteria, comprising 5917 patients (OCT n = 2075; IVUS n = 3842). OCT-PCI versus IVUS-guided PCI comparison yielded no statistically significant results for all the outcomes; MACE (RR 0.78; 95% confidence interval [CI], 0.57-1.09; p = 0.14), cardiac mortality (RR 0.97; 95% CI, 0.27-3.46; p = 0.96), all-cause mortality (RR 0.74; 95% CI, 0.39-1.39; p = 0.35), MI (RR 1.27; 95% CI, 0.52-3.07; p = 0.60), ST (RR 0.70; 95% CI, 0.13-3.61; p = 0.67), TLR (RR 1.09; 95% CI, 0.53-2.25; p = 0.81), and stroke (RR 2.32; 95% CI, 0.42-12.90; p = 0.34). Furthermore, there was no effect modification on meta-regression including demographics, comorbidities, lesion location, lesion length, and stent type.

CONCLUSIONS

In this meta-analysis, OCT-guided PCI was associated with no difference in clinical outcomes compared with IVUS-guided PCI.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency

Evaluation of acute percutaneous coronary intervention (PCI) results and long-term follow-up remains challenging with ongoing stent designs. Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion, improving overall PCI results and reducing adverse cardiac events. Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results. Digital stent enhancement methods have been well validated and improved stent strut visualization. Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure. With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results. We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

External elastic lamina vs. luminal diameter measurement for determining stent diameter by optical coherence tomography: an ILUMIEN III substudy

AIMS

Optical coherence tomography (OCT)-guided external elastic lamina (EEL)-based stent sizing is safe and as effective as intravascular ultrasound in achieving post-procedural lumen dimensions. However, when compared with automated lumen diameter (LD) measurements, this approach is time-consuming. We aimed to compare vessel diameter measurements and stent diameter selection using either of these approaches and examined whether applying a correction factor to automated LD measurements could result in selecting similar stent diameters to the EEL-based approach.

METHODS AND RESULTS

We retrospectively compared EEL-based measurements vs. automated LD in reference segments in 154 OCT acquisitions and derived a correction factor for stent sizing using the ratio of EEL to LD measurements. We then prospectively applied the correction factor in 119 OCT acquisitions. EEL could be adequately identified in 100 acquisitions (84%) at the distal reference to allow vessel diameter measurement. Vessel diameters were larger with EEL-based vs. LD measurements at both proximal (4.12 ± 0.74 vs. 3.14 ± 0.67 mm, P < 0.0001) and distal reference segments (3.34 ± 0.75 vs. 2.64 ± 0.65 mm, P < 0.0001). EEL-based downsizing led to selection of larger stents vs. an LD-based upsizing approach (3.33 ± 0.47 vs. 2.70 ± 0.44, P < 0.0001). Application of correction factors to LD [proximal 1.32 (IQR 1.23-1.37) and distal 1.25 (IQR 1.19-1.36)] resulted in discordance in stent sizing by >0.25 mm in 63% and potentially hazardous stent oversizing in 41% of cases.

CONCLUSION

EEL-based stent downsizing led to selection of larger stent diameters vs. LD upsizing. While applying a correction factor to automated LD measurements resulted in similar mean diameters to EEL-based measurements, this approach cannot be used clinically due to frequent and potentially hazardous stent over-sizing.

Relationship between stent expansion and fractional flow reserve after percutaneous coronary intervention: a post hoc analysis of the DOCTORS trial

BACKGROUND

The best criteria for adequate stent expansion assessment by intracoronary imaging remain debated and their correlation with post-PCI FFR values is unknown.

AIMS

This study aimed to analyse the relationship between stent expansion criteria using optical coherence tomography (OCT) analysis and the final PCI functional result.

METHODS

This post hoc analysis of the DOCTORS study included non-ST-elevation segment ACS patients undergoing OCT-guided PCI. The procedure functional result was assessed by the measurement of fractional flow reserve (FFR). Stent expansion was assessed on OCT runs according to the DOCTORS criteria and ILUMIEN III criteria.

RESULTS

The study included N=116 patients (age: 60.8±11.5 years; male gender: 71%). The final expansion was considered optimal in 10%, acceptable in 9% and unacceptable in 81% of the stents according to ILUMIEN III criteria, although being successful in 70% of the patients according to the DOCTORS criteria. Hypertension and larger proximal reference segment dimension were independent predictors of inadequate device ILUMIEN III expansion. FFR values were, respectively, 0.93 (0.91-0.95) versus 0.95 (0.92-0.97) in patients with optimal+acceptable versus unacceptable ILUMIEN III expansion (p=0.22), 0.94 (0.91-0.97) versus 0.95 (0.93-0.97) in patients with optimal versus non-optimal DOCTORS expansion (p=0.23), and 0.95 (0.92-0.97) versus 0.92 (0.90-0.95) in patients with minimal stent area ≥4.5 mm2 versus <4.5 mm2 (p=0.03).

CONCLUSIONS

In this selected population, no relationship was observed between optimal stent expansion according to ILUMIEN III or DOCTORS OCT criteria and final post-PCI FFR values.

Intracoronary optical coherence tomography: state of the art and future directions

Optical coherence tomography (OCT) has been increasingly utilised to guide percutaneous coronary intervention (PCI). Despite the diagnostic utility of OCT, facilitated by its high resolution, the impact of intracoronary OCT on clinical practice has thus far been limited. Difficulty in transitioning from intravascular ultrasound (IVUS), complex image interpretation, lack of a standardised algorithm for PCI guidance, and paucity of data from prospective clinical trials have contributed to the modest adoption. Herein, we provide a comprehensive up-do-date overview on the utility of OCT in coronary artery disease, including technical details, device set-up, simplified OCT image interpretation, recognition of the imaging artefacts, and an algorithmic approach for using OCT in PCI guidance. We discuss the utility of OCT in acute coronary syndromes, provide a summary of the clinical trial data, list the work in progress, and discuss the future directions.

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-guided percutaneous coronary intervention: a review of current clinical applications

Optical coherence tomography (OCT) is an emerging high-resolution intravascular imaging modality that can provide physicians with critical information, thereby enabling precise characterization of plaque morphology and luminal geometry and facilitating pre-intervention lesion assessment. As OCT has a higher sensitivity for lipid-rich plaque characterization than intravascular ultrasound, vulnerable plaque detection by OCT has thus been investigated. By evaluating both the calcium thickness and arc, OCT can be the ideal method for determining both the indication and endpoint of rotational atherectomy for calcified lesions prior to stent implantation. OCT has become applicable for the optimization of stent implantation with immediate and semi-automatic quantification of stent apposition and expansion to achieve potentially better clinical outcomes. In bifurcation lesions, OCT allows the visualization of the stent-link location overhanging the side-branch ostium and the guidewire recrossing point prior to the final kissing balloon inflation through three-dimensional reconstructed OCT images, providing us with deep insights into the mechanical optimization of stent struts. Furthermore, recent studies have reported several OCT-derived predictors of adverse clinical events. Important limitations of OCT, including the excessive contrast volume needed and observation of aorto-ostial lesions, may partially be overcome through the use of low-molecular-weight dextran and a guide extension catheter. The clinical applications of OCT have been expanding, and evidence on its clinical utility has been accumulating.

Three-dimensional optical coherence tomography versus intravascular ultrasound in percutaneous coronary intervention for the left main coronary artery

We aimed to compare the intravascular imaging findings, and clinical outcomes between three-dimensional optical coherence tomography (OCT)- and intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) for the left main coronary artery (LMCA). We enrolled 331 patients underwent OCT- or IVUS-guide single crossover stenting across the side branch (SB) and subsequent kissing balloon inflation (KBT) for LMCA bifurcation. Primary endpoint was defined as a composite of cardiac death, myocardial infarction, and target lesion revascularization. Of 331 patients, 58 patients (17.5%) underwent OCT-guide PCI. OCT-guide PCI associated with higher frequency of proximal optimization technique (POT) (98.3% vs 85.3%, P = 0.013) and smaller balloon size of POT (4.29 ± 0.44 mm vs 4.43 ± 0.42, P = 0.02) than IVUS-guide PCI. Although maximal stent area at LMCA and minimal stent area at main vessel were significantly smaller in OCT-guide PCI in intravascular imaging (P = 0.01, and P = 0.002, respectively), the restenosis rate at follow-up angiography was comparable in both groups (15.2% vs. 9.4%, P = 0.387). Cumulative rate of primary endpoint was not significantly different between 2 groups both before and after propensity score adjustment (7.0% vs. 7.4%, P = 0.98 and 2.6% vs. 7.3%, P = 0.18). In conclusion, the clinical outcomes at 1 year were comparable, suggesting OCT- and IVUS-guided PCI for LMCA were similarly feasible. The balloon size of POT in OCT-guide PCI might be influenced by the limited visibility in the proximal LMCA.

Optical Coherence Tomography: Current Applications for the Assessment of Coronary Artery Disease and Guidance of Percutaneous Coronary Interventions

INTRODUCTION

Coronary angiography (CAG) is the standard modality for assessment of coronary stenoses and intraprocedural guidance of percutaneous coronary interventions (PCI). However, the limitations of CAG are well recognized. Intracoronary imaging (ICI) can potentially overcome these limitations. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the main ICI techniques utilized in clinical practice.

AIM

This narrative literature review addresses the current clinical applications of OCT in relation to IVUS and CAG in patients with coronary artery disease (CAD). Items reviewed are: technical implications of OCT and IVUS, lesion characterization and decision-making, stent optimization criteria, post-stenting results, safety in terms of procedural complications, clinical outcomes, and indications.

MAIN FINDINGS

OCT is able to reveal more detail than IVUS due to its higher resolution. However, this higher resolution comes at the cost of a lower penetration depth. Pre-stenting OCT results in procedural change in more than 50% of the cases in terms of stent length and diameter. Post-stenting OCT resulting in stent optimization is reported in at least 27% of the cases. Malapposition and under-expansion are treated with post-dilatations, while edge dissections are treated with additional stent placement. Stent expansion, stent apposition, distal stent edge dissections, and reference lumen areas seem to be the most important stent optimization criteria for both decision-making and for reducing the risk of adverse events during follow-up. Both OCT and IVUS are superior in terms of post-stenting results compared with CAG alone. However, there is no consensus about whether OCT guidance results in better stent expansion than IVUS guidance. OCT, IVUS, and CAG are safe procedures with few reported procedural complications. In general, OCT guidance seems to contribute to favorable clinical outcomes compared with CAG guidance only. However, OCT guidance results in similar clinical outcomes as with IVUS guidance. OCT could be considered for lumen assessment and stent-related morphology in more complex cases in which CAG interpretation remains uncertain. Since OCT and IVUS have distinct characteristics, these techniques are complementary and should be considered carefully for each patient case based on the benefits and limitations of both techniques.

Current status of hybrid intravascular ultrasound and optical coherence tomography catheter for coronary imaging and percutaneous coronary intervention

Both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) play a crucial role in elucidating the pathophysiology of coronary artery disease (CAD) with the goal to improve patient outcomes of medical and/or interventional CAD management. However, no single intravascular imaging technique has been proven to provide complete and detailed evaluation of all CAD lesions due to some limitations. Although sequential use of multiple modalities may sometimes be performed, there may be issues related to risk, time, and cost. To overcome these problems, several hybrids involving dual-probe combined IVUS-OCT catheters have been developed. The aim of this review article is to demonstrate some limitations of stand-alone imaging devices for evaluation of CAD, summarize the advances in hybrid IVUS-OCT imaging devices, discuss the technical challenges, and present the potential value in the clinical setting, especially in patients receiving medical or interventional CAD management.

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.

Comparison of optical coherence tomography-guided versus intravascular ultrasound-guided percutaneous coronary intervention: Rationale and design of a randomized, controlled OCTIVUS trial

BACKGROUND

The clinical value of intracoronary imaging for percutaneous coronary intervention (PCI) guidance is well acknowledged. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the most commonly used intravascular imaging to guide and optimize PCI in day-to-day practice. However, the comparative effectiveness of IVUS-guided versus OCT-guided PCI with respect to clinical end points remains unknown.

METHODS AND DESIGN

The OCTIVUS study is a prospective, multicenter, open-label, parallel-arm, randomized trial comparing the effectiveness of 2 imaging-guided strategies in patients with stable angina or acute coronary syndromes undergoing PCI in Korea. A total of 2,000 patients are randomly assigned in a 1:1 ratio to either an OCT-guided PCI strategy or an IVUS-guided PCI strategy. The trial uses a pragmatic comparative effectiveness design with inclusion criteria designed to capture a broad range of real-world patients with diverse clinical and anatomical features. PCI optimization criteria are predefined using a common algorithm for online OCT or IVUS. The primary end point, which was tested for both noninferiority (margin, 3.1 percentage points for the risk difference) and superiority, is target-vessel failure (cardiac death, target-vessel myocardial infarction, or ischemia-driven target-vessel revascularization) at 1 year.

RESULTS

Up to the end of July 2020, approximately 1,200 "real-world" PCI patients have been randomly enrolled over 2 years. Enrollment is expected to be completed around the midterm of 2021, and primary results will be available by late 2022 or early 2023.

CONCLUSION

This large-scale, multicenter, pragmatic-design clinical trial will provide valuable clinical evidence on the relative efficacy and safety of OCT-guided versus IVUS-guided PCI strategies in a broad population of patients undergoing PCI in the daily clinical practice.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention With Low-Molecular-Weight Dextran - Effect on Renal Function

BACKGROUND

The excessive volume of contrast needed is a significant limitation of optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI). Low-molecular-weight dextran (LMWD) has been used for OCT image acquisition instead of contrast media. This study compared the effects of OCT-guided PCI using LMWD on renal function and clinical outcomes to those of intravascular ultrasound (IVUS)-guided PCI.

METHODS AND RESULTS

In all, 1,183 consecutive patients who underwent intracoronary imaging-guided PCI were enrolled in this single-center, retrospective, observational study. After propensity score matching, 133 pairs of patients were assigned to undergo either OCT-guided PCI using LMWD or IVUS-guided PCI. There was no significant change from baseline in the primary endpoint, serum creatinine concentrations, after the procedure in either group. There were no significant differences between the OCT and IVUS groups in the volume of contrast medium, the incidence of contrast-induced nephropathy (1.5% vs. 2.3%; P=0.65), and major adverse cardiovascular events (MACE) at 30 days (2.3% vs. 6.0%; P=0.12) and 12 months (2.3% vs. 3.0%; P=0.70) after the procedure. Kaplan-Meier analysis at the 12-month follow-up revealed no significant difference in the incidence of MACE between the 2 groups (P=0.75).

CONCLUSIONS

OCT-guided PCI using LMWD did not negatively affect renal function and achieved similar short- and long-term clinical outcomes to IVUS-guided PCI.

How to guide PCI?: A network meta-analysis

BACKGROUND

Traditional coronary angiography (CA) as a main technique has been used to determine the coronary artery anatomy and guide percutaneous coronary intervention (PCI). We mainly focused on whether the new techniques could improve the patients' mortality, major adverse cardiovascular events (MACEs), and myocardial infarction.

METHODS

For the network meta-analysis, we searched the trials of different PCI guidances from MEDLINE, Current Contents Connect, Google Scholar, EMBASE, Cochrane Library, PubMed, Science Direct, and Web of Science. The last search date was December 10, 2018.

RESULTS

The analyses of all results found that there was no significant difference in mortality among the groups. Randomized clinical trials (RCT) analysis showed that intravascular ultrasound (IVUS)-guided PCI was significantly superior to CA, fractional flow reserve, instantaneous wave-free ratio, optical coherence tomography. However, CA, fractional flow reserve, instantaneous wave-free ratio, and optical coherence tomography showed no difference in reducing mortality. The analyses of all results found that there was no significant difference in the incidence of MACEs among the groups. RCTs analysis showed that IVUS-guided PCI was significantly superior to CA, but there was no significant difference among the other groups. The analyses of all results or RCTs showed that there was no significant difference in myocardial infarction incidence among the groups.

CONCLUSION

IVUS-guided PCI is an effective method to decrease all-cause death MACEs.

Efficacy and Reproducibility of Attenuation-Compensated Optical Coherence Tomography for Assessing External Elastic Membrane Border and Plaque Composition in Native and Stented Segments - An In Vivo and Histology-Based Study

BACKGROUND

Attenuation-compensated (AC) technique was recently introduced to improve the plaque characterization of optical coherence tomography (OCT). Histological validation demonstrated promising results but the efficacy and reproducibility of this technique for assessing in-vivo tissue composition remains unclear.

METHODS AND RESULTS

OCT images portraying native (n=200) and stented (n=200) segments and 31 histological cross-sections were analyzed. AC-OCT appeared superior to conventional (C)-OCT in detecting the external elastic lamina (EEM) borders (76% vs. 65.5%); AC-OCT enabled larger EEM arc detection compared with C-OCT (174.2±58.7° vs. 137.5±57.9°; P<0.001). There was poor agreement between the 2 techniques for detection of lipid in native and lipid and calcific tissue in stented segments (κ range: 0.164-0.466) but the agreement of C-OCT and AC-OCT was high for calcific tissue in native segments (κ=0.825). Intra and interobserver agreement of the 2 analysts was moderate to excellent with C-OCT (κ range: 0.681-0.979) and AC-OCT (κ range: 0.733-0.892) for all tissue types in both native and stented segments. Ex-vivoanalysis demonstrated that C-OCT was superior to AC-OCT (κ=0.545 vs. κ=0.296) for the detection of the lipid component in native segments.

CONCLUSIONS

The AC technique allows better delineation of the EEM but it remains inferior for lipid pool detection and neointima characterization. Combined AC- and C-OCT imaging may provide additional value for complete assessment of plaque and neointima characteristics.

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.

Intracoronary Optical Coherence Tomography 2018: Current Status and Future Directions

The advent of intravascular imaging has been a significant advancement in visualization of coronary arteries, particularly with optical coherence tomography (OCT) that allows for high-resolution imaging of intraluminal and transmural coronary structures. Accumulating data support a clinical role for OCT in a multitude of clinical scenarios, including assessing the natural history of atherosclerosis and modulating effects of therapies, mechanisms of acute coronary syndromes, mechanistic insights into the effects of novel interventional devices, and optimization of percutaneous coronary intervention. In this state-of-the-art review, we provide an overview of the published data on the clinical utility of OCT, highlighting the areas that need further investigation and the current barriers for further adoption of OCT in interventional cardiology practice.

Routine use of optical coherence tomography in bioresorbable vascular scaffold implantation: insights on technique optimization and long-term outcomes

BACKGROUND

Data from prior studies have shown increased risk of adverse outcomes with bioresorbable vascular scaffolds (BVS) compared with drug-eluting stents.

OBJECTIVE

The objective of this study was to study the long-term outcomes with routine use of optical coherence tomography (OCT) for optimization of BVS implantation.

PATIENTS AND METHODS

Clinical, procedural, and outcome data were collected for all patients who received ABSORB BVS between February 2014 and March 2016 in our tertiary center (n=86). Preimplantation and postimplantation OCT was performed in all cases. Outcomes of interest included acute device success and long-term clinical outcomes including cardiac mortality, target vessel myocardial infarction, ischemia-driven target lesion revascularization, and scaffold thrombosis.

RESULTS

A total of 86 patients were included (106 lesions, 115 BVS implanted). Mean age was 59.5±10.9 years, with 66% men. Mean lesion length was 25.2±15.6 mm and mean reference vessel diameter was 3.42±0.45 mm. Type B2/C accounted for 40% of the lesions. All scaffold implantations followed the predilation, proper sizing, and postdilation strategy. Of the 115 scaffolds analyzed, 11 (9.5%) required further intervention based on prespecified OCT endpoints. On multivariate regression analysis, complex coronary lesion (type B2/C) was the single independent predictor of OCT use in scaffold optimization (odds ratio=6.3, 95% confidence interval: 1.3-7.8, P=0.02). At a mean follow-up duration of 31±7.1 months, no cases of cardiac mortality, target vessel myocardial infarction, ischemia-driven target lesion revascularization, or scaffold thrombosis were reported.

CONCLUSION

Operators may consider OCT use for optimization of BVS implantation particularly in patients with complex coronary lesions.