Workflow-based Framework to Aid with High-Definition Intravascular Ultrasound-Optimised Coronary Stenting: Introducing IVUS 123 Essentials

Why Is Intravascular Ultrasound Guidance Underutilized in Percutaneous Coronary Intervention?: It Is Not "All About the Benjamins".

The concept of stenting—intravascular mechanical support by transluminally placed endoprostheses—was first proposed by Charles Dotter >30 years ago.1 As an intrinsic property of the metallic endoprostheses, early thrombotic occlusion of freshly deployed stents has been a concern since their introduction to human coronary circulation in 1986.2 The unacceptably high rates (up to 24%) of thrombotic events seen in early clinical experience were first approached pharmacologically by aggressive anticoagulation with low-molecular-weight dextran, dipyridamole, and warfarin. Although this strategy helped reduce the incidence of stent thrombosis into a single-digit range, the benefit was obtained at a cost of significantly longer hospitalization and increased hemorrhagic/vascular complications. As intravascular ultrasound (IVUS) began to have widespread use in the clinical environment in the early 1990s, the importance of mechanical optimization at stent deployment for the prevention of stent thrombosis was underscored. The collaborative work of J.M. Tobis and A. Colombo demonstrated an unexpectedly high percentage of IVUS-detected stent deployment issues, including incomplete stent expansion, incomplete apposition, and asymmetric expansion, even after angiographically successful results.3,4 These observations led to the concept of high-pressure stent deployment with IVUS guidance, achieving lower rates of subacute thrombosis with antiplatelet therapy alone (aspirin and ticlopidine).5 The superiority of this antiplatelet therapy after “optimal” stent expansion with routine high pressure post-dilatation was subsequently confirmed by several randomized trials when compared with other antithrombotic regimens.6,7 See p 43 Nevertheless, stent thrombosis has not been eliminated; in this modern stent era, the incidence is reported to be ≈1% overall and can be more frequent in high-risk patient/lesion subsets or multivessel procedures.6,8 Despite the reduced relative incidence, the absolute number of patients with stent thrombosis is increasing in parallel with the exponential increase in the use of stents in the broad spectrum of complex lesions. The clinical consequences …

Grey-scale Intravascular ultrasound (IVUS) has provided significant insights into atherosclerosis and consequently has helped to shape interventional cardiology practice. In the era of contemporary percutaneous coronary intervention (PCI) practice using newer intra coronary imaging modalities like virtual histology IVUS (VH-IVUS, Near infra red spectroscopy (NIRS) and Optical Coherence Tomography (OCT), the question remains if IVUS is relevant. In this thesis, we sought to determine the continuing usefulness of IVUS. In chapter 2 of this thesis, we reviewed the evidence for the usefulness of IVUS of IVUS especially in the complex coronary lesion subsets like left main stem, ostial coronary, bifurcation, calcified lesions and chronic total occlusions. We showed that IVUS still has a very useful role to play in especially in PCI of these complex lesion subsets. In chapter 3, we showed the positive relationship between conventional cardiovascular risk factors and atherosclerotic plaque volume in the left main stem. We assessed total atheroma volume and percent atheroma volume in 105 patients who had IVUS performed for assessment of intermediate lesion in the LMS. Using multivariate analysis, we determined that male gender and positive family history predicted increased atherosclerotic plaque burden. This knowledge may help us to target this high-risk patient cohort for early intervention in the LMS. In chapter 4, using IVUS, we studied 156 patients with angiographic intermediate or significant coronary lesions involving the LMS or proximal left anterior descending or left circumflex artery lesions (DV) that were referred for morphologic assessment of atherosclerotic plaque. We showed that irrespective of the indication of the IVUS i.e. intermediate lesions in the LMS or proximal DV, distal LMS is invariably involved. This information is crucial because it will help interventional cardiologist achieve optimal stent result especially in the distal LMS. In chapter 5, we studied the long term clinical outcome of 91 patients who had IVUS for intermediate LMS lesions, who were then referred to conventional management strategies of PCI, Coronary artery bypass surgery (CABG) or medical therapy (MT). The objective of this study was to determine the relevance of conventional IVUS diagnostic paradigms in the LMS – minimal luminal diameter (MLD) of CCS 2), need for target lesion or target vessel revascularization (TLR/TVR) or CABG, requirement for admission (due to angina, acute myocardial infarction [AMI] and all cause mortality. We found that patients who underwent PCI or CABG for significant LMS lesion using these LMS IVUS diagnostic paradigms had good long-term clinical outcome. Deferral to medical therapy on the basis of intermediate LMS lesion based on LMS IVUS MLD > 2.8mm and MLA > 6mm² were associated with low MACE rates. We concluded that these traditional IVUS diagnostic paradigms are still relevant and safe. In conclusion, we confirmed that IVUS still has a vital role to play, especially in LMS, in the era of contemporary PCI practice.

Both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) can provide critical information that facilitates pre-interventional lesion assessment and post-interventional stent assessment and both have the potential to influence treatment strategy. Meta-analyses of randomized trials and observational studies comparing IVUS-guided percutaneous coronary intervention (PCI) with angiography-guided PCI revealed that IVUS-guided procedures reduce the incidence of target vessel revascularization, stent thrombosis, and myocardial infarction. Several IVUS criteria have been proposed to optimize stent implantation. Whether these criteria can be directly used to facilitate OCT-guided stent implantation needs to be clarified. Recent studies revealed several IVUS- and OCT-derived predictors of adverse events during PCI. Attenuated coronary plaque on IVUS might be related to deterioration of coronary flow after PCI, whereas tissue characterization on IVUS radiofrequency signal analysis can also detect coronary plaques at high risk for distal embolization. Thin-cap fibroatheroma on OCT has been proposed as a useful characteristic for predicting the no-reflow phenomenon. Furthermore, ostial plaque distribution as assessed by IVUS is reported to be a useful predictor of side-branch occlusion after PCI, whereas the severity of calcified lesions may be better assessed by OCT. Although IVUS and OCT each have inherent strengths and weaknesses, these techniques can complement each other, and selective utilization in appropriate patient subgroups or combined usage is expected to be beneficial during PCI procedures.

Alice K. Jacobs, MD, FACC, FAHA, Chair Jeffrey L. Anderson, MD, FACC, FAHA, Chair-Elect Nancy Albert, PhD, CCNS, CCRN, FAHA Mark A. Creager, MD, FACC, FAHA Steven M. Ettinger, MD, FACC Robert A. Guyton, MD, FACC Jonathan L. Halperin, MD, FACC, FAHA Judith S. Hochman, MD, FACC, FAHA

Case presentation : A 56-year-old man presented to the hospital with chest pain and a non–ST-segment elevation myocardial infarction. Thrombotic plaque rupture in the left anterior descending coronary artery was treated with an everolimus-eluting stent. After stent deployment, angiography demonstrated the presence of a hazy opacity at the distal edge of the stent, and there was concern about a possible edge dissection. Optical coherence tomography (OCT) imaging of the opacity showed residual thrombus and no dissection. Subsequent aspiration thrombectomy and balloon dilation effectively treated the lesion without deployment of an additional stent. OCT is an intravascular imaging modality that utilizes near-infrared light to generate cross-sectional blood vessel images. OCT is similar to intravascular ultrasound (IVUS), and both OCT and IVUS provide information about intravascular anatomy that far exceeds the level of detail obtained from conventional contrast cineangiography. With the use of light rather than ultrasound reflectance, OCT generates in vivo images of coronary arteries and deployed stents with up to 10 to 15 μm of spatial resolution compared with the 100- to 200-μm resolution of IVUS. Although the spatial resolution of OCT is markedly superior to that of IVUS, near-infrared light does not penetrate tissue as effectively as sound, and therefore OCT imaging depths range from 1 to 3 mm into the vessel wall, whereas IVUS imaging depths range from 4 to 10 mm (Table). Additionally, near-infrared light is scattered by red blood cells, and therefore OCT imaging requires transient blood clearing during image acquisition. View this table: Table. Comparison of FD-OCT and IVUS The speed of light was initially a central challenge to developing a “clinically friendly” OCT system. Light travels too quickly for direct measurement of differential reflectance caused by vascular structures, and the original time delay OCT (TD-OCT) systems utilized a moving reference mirror to calibrate reflected light waves for image …

Objective - Investigation of the cost-effectiveness of intravascular ultrasound (IVUS) guided percutaneous coronary intervention (PCI) compared to PCI guided by coronary angiography (CAG). Methods - One hundred and eight men referred for PCI, were randomized to IVUS or CAG guided PCI. After 6 months, the patients were subjected to a study related clinical and invasive follow-up investigation by CAG, IVUS and intracoronary Doppler flow measurements. Incremental costs of IVUS guided procedures and costs of reinterventions were estimated using the Activity Based Costing (ABC) method. Results - Patients randomized to IVUS guided PCI experienced an improved clinical outcome, with lower angina levels than patients in the CAG guided group. The initial cost of performing IVUS guidance was increased due to extra procedure time, IVUS catheters and slightly more balloons and stents, but fewer patients in the IVUS guided group needed re-intervention. Overall, these savings outweighed the initial cost increase. Conclusion - Our data suggest that when performing IVUS guided PCI, costs as well as benefits increase. The increased benefits measured as cost savings resulting from less restenosis outweigh the cost increase from performing the IVUS guided PCI as opposed to CAG guided PCI.

Attenuated plaque on intravascular ultrasound (IVUS) and low attenuation plaque on computed tomography angiography (CTA) are associated with no-reflow phenomenon during percutaneous coronary intervention (PCI). However, evaluation by a single modality has been unable to satisfactorily predict this phenomenon. We investigated whether the combination of IVUS and CTA findings can ameliorate the predictive potential for no-reflow phenomenon after stent implantation during PCI in stable coronary artery disease (CAD). A total of 988 lesions of 707 stable CAD patients who underwent coronary CTA before PCI were enrolled. PCI was performed with preprocedural IVUS and stent implantation. As for plaque characters, very low attenuation plaque (CTA v-LAP) whose minimum density was < 0 Hounsfield units on CTA and attenuated plaque (IVUS AP) on IVUS were evaluated. No-reflow phenomenon was observed in 22 lesions (2.2%) of 19 patients (2.7%). Both CTA v-LAP and IVUS AP were much more frequently observed in patients with no-reflow phenomenon. Positive (PPV) and negative predictive values (NPV) and accuracy for prediction of no-reflow were almost equivalent between CTA v-LAP (13.2, 99.6, and 87.0%) and IVUS AP (15.7, 99.8, and 89.0%). The combination of CTA v-LAP and IVUS AP markedly ameliorated PPV (31.7%) without deterioration of NPV (99.7%) and increased the diagnostic accuracy (95.5%). These findings showed that the combination of CTA v-LAP and IVUS AP improved the predictive power for no-reflow phenomenon after coronary stenting in stable CAD patients, suggesting the usefulness of combined estimation by using CTA and IVUS for predicting no-reflow phenomenon during PCI in clinical practice.

Objective To explore the value of application of intravascular ultrasound (IVUS) guidance and analyze the limitations of coronary angiography in the assessment and to provide valuable information for percutaneous coronary intervention (PCI) treatment of left main (LM) lesion. Methods The 60 patients with LM lesion were enrolled in this study.The patients were divided into two groups: ostium and trunk lesion of LM group and distal or bifurcation lesion of LM group, 30 cases in each group.Combined coronary angiography (CAG) and IVUS was used to assess the lesion, guide the PCI treatment and evaluate the immediate effect of PCI after stent implantation.Differences of two groups were compared. Results The mean reference diameter, the minimum lumen diameter and the minimum lumen area of LM lesion measured by coronary angiography were significantly smaller than that by IVUS (all P<0.05). In 8 cases (26.7%) of the ostium and trunk of LM lesion group, the measurement parameters of were significantly different between those CAG and IVUS results.CAG and IVUS guidance for distal left main bifurcation stent policy show larger differences, those who do not match were up to 30%.The proportion of post-dilation was significantly higher in IVUS guided group than in angiography guided group (P<0.05). Conclusions Compared with IVUS, CAG cannot accurately diagnose coronary artery disease with left main disease, treatment with PCI CAG guidance accuracy is also limited.We recommend the routine application of IVUS in the PCI treatment of LM lesion. Key words: Left main coronary artery; Angioplasty, transluminal, percutaneous coronary; Coronary artery angiography; Ultrasonography, interventional

Clinical trial data suggest that intravascular ultrasound (IVUS) may improve clinical outcomes after PCI. The aim of this study was to investigate the safety of IVUS in its broader use for percutaneous coronary intervention (PCI). A total of 11,570 consecutive patients undergoing PCI between 2008 and 2014 in Japan were analyzed. Associations between IVUS use, PCI-related complications were assessed with logistic regression and propensity score matching analyses. Subgroup analysis was performed in elective PCI patients. IVUS was used in 84.8% of patients (N = 9814; IVUS group); its use was almost universal in elective PCIs (90.8 vs. 81.7% in urgent/emergent PCIs, P < 0.001). The non-IVUS group were older (68.7 ± 11.4 vs. 67.9 ± 10.8years, P = 0.004), with more comorbid conditions. The non-IVUS group had smaller stent lumens (2.97 ± 0.42mm vs. 3.09 ± 0.45mm, P < 0.001) and a higher proportion of plain old balloon angioplasty. After matching, a lower rate of flow-impairing coronary dissections was observed in the IVUS group, although this was limited only to elective PCIs, not among urgent/emergent PCIs (non-IVUS vs. IVUS; 2.7% vs. 1.0%, P = 0.018, 0.7% vs. 1.2%, P = 0.32, respectively). With a multivariate logistic regression analysis, IVUS use remained an independent predictor to reduce risk of flow impairing severe coronary dissection among elective PCIs (odds ratio 0.38, 95% confidence interval 0.22-0.66: P = 0.001). In this Japanese PCI registry, IVUS was used extensively during the study period, particularly in elective cases. Using IVUS was associated with a lower event rate of flow-impairing coronary dissections that was limited to elective PCIs, not among urgent/emergent PCIs, without increasing PCI-related complications.

Coronary angiography has long been the standard for coronary imaging, but it has limitations in assessing vessel wall anatomy and guiding percutaneous coronary intervention (PCI). Intracoronary imaging techniques like intravascular ultrasound (IVUS) and optical coherence tomography (OCT) can overcome these limitations. IVUS uses ultrasound and OCT uses near-infrared light to visualize coronary pathology in unique ways due to differences in temporal and spatial resolution. These techniques have evolved to offer clinical utility in plaque characterization and vessel assessment during PCI. Meta-analyses and adjusted observational studies suggest that both IVUS and OCT-guided PCI correlate with reduced cardiovascular risks compared to angiographic guidance alone. While IVUS demonstrates consistent clinical outcome benefits, OCT evidence is less robust. IVUS has progressed from early motion detection to high-resolution systems, with smaller compatible catheters. OCT utilizes near infrared light to achieve unparalleled resolutions, but requires temporary blood clearance for optimal imaging. Enhanced visualization and guidance make IVUS and OCT well-suited for higher risk PCI in patients with diabetes and chronic kidney disease by allowing detailed visualization of complex lesions and ensuring optimal stent deployment and positioning in PCI for patients with type 2 diabetes and chronic kidney disease, improving outcomes. IVUS and recent advancements in zero- and low-contrast OCT techniques can reduce nephrotoxic contrast exposure, thus helping to minimize PCI complications in these high-risk patient groups. IVUS and OCT provide valuable insights into coronary pathophysiology and guide interventions precisely compared to angiography alone. Both have comparable clinical outcomes, emphasizing the need for tailored imaging choices based on clinical scenarios. Continued refinement and integration of intravascular imaging will likely play a pivotal role in optimizing coronary interventions and outcomes. This systematic review aims to delve into the nuances of IVUS and OCT, highlighting their strengths and limitations as PCI adjuncts.

C-21 | The use of intravascular ultrasound (IVUS) during percutaneous coronary intervention does not reduce all cause in-hospital mortality but doubles the cost with higher utilization in privately insured patients

This review highlights the evidence surrounding the adjunctive diagnostic and therapeutic benefits of intravascular ultrasound (IVUS) during percutaneous coronary intervention (PCI). Meta-analyses of randomized trials demonstrate that IVUS has a major impact on PCI-related outcomes with drug-eluting stents by reducing cardiovascular mortality and repeat revascularization. Its application in calcific coronary artery disease has helped identify the benefits and safety of coronary atherectomy, along with playing an important role for primarily guiding PCI while significantly reducing contrast volume in individuals with renal dysfunction. IVUS applications have been extended to the realms of CTO intervention, aneurysmal coronary disease, and iatrogenic/spontaneous coronary artery dissection. IVUS is also a proven cost-effective strategy. Nevertheless, despite these benefits, the global uptake of IVUS-guided PCI remains low. IVUS plays a pivotal role during PCI, particularly complex calcific and long lesions. IVUS-guided PCI is safe, cost-effective, and associates with substantial reductions in MACE. However, the worldwide uptake of IVUS-guided PCI remains considerably low. Further efforts are required to promote this evidence-based PCI strategy among the global interventional cardiology community to further improve the outcomes of our PCI candidates.

Validation of Intravascular Ultrasound-Defined Optimal Stent Expansion Criteria for Favorable 1-Year Clinical Outcomes.

Introduction: Intravascular Ultrasound (IVUS) is a catheter-based real-time imaging procedure that assists in both diagnosis and treatment during Percutaneous Coronary Intervention (PCI). Over the years, IVUS-guided PCI have become more popular. In this study, we aimed to analyze the trends of use of IVUS-guided PCI, adjusted in-hospital mortality, hospital length of stay (LOS) and inpatient cost over the years. Methods: Data were extracted from the National Inpatient Sample (NIS) 2014 through 2019 Database. The NIS was searched for PCI with and without IVUS in adult patients (age ≥ 18) using ICD 9 and 10 codes. Outcomes of interest were utilization rates of IVUS during PCI, trend of adjusted in-hospital mortality, adjusted mean LOS and adjusted mean cost. Multivariate logistic and linear regression analysis was used accordingly to adjust for confounders. STATA software was used for analysis. Results: Of 2,871,865 PCIs in 2014 through 2019, 201,075 (7.0%) were coupled with IVUS. The use of IVUS during PCI steadily increased from 6.2% in 2014 to 9.3% in 2019 (trend p&lt;0.001). The adjusted in-hospital mortality and inpatient LOS for PCI with IVUS showed statistically insignificant trend of higher mortality (1.3% in 2014 vs. 1.6% in 2019, trend p=0.053) and shorter LOS (3.2 days in 2014 vs. 3.0 days in 2019, trend p=0.148). The mean adjusted cost steadily increased over the years for patients undergoing PCI with IVUS (24236$ in 2014 vs. 28700$ in 2019, trend p=0.012). Conclusions: There is a steady rise in use of IVUS during PCI. There is a steady hike in hospital costs for PCI with IVUS hospitalizations however in-hospital mortality and LOS remain the same.