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

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

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

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

Comparison of plaque morphology between peripheral and coronary artery disease (from the CLARITY and ADAPT-DES IVUS substudies)

OBJECTIVE

The aim of this study was to help understand the different outcomes when treating peripheral arterial disease (PAD) versus coronary artery disease (CAD). We compared plaque morphology between PAD and CAD using intravascular ultrasound.

METHODS

Complete Lesion Assessment with ffR and IVUS TechnologY (CLARITY) was a prospective, multicenter trial that enrolled 50 PAD patients with a lower extremity wound fed by a tibial or a peroneal artery with diameter stenosis more than 50%. Assessment of Dual AntiPlatelet Therapy With Drug Eluting Stents (ADAPT-DES) was a prospective, multicenter, registry that enrolled 8582 CAD patients. We compared preintervention intravascular ultrasound findings in 42 PAD lesions from CLARITY versus 79 matched CAD lesions from ADAPT-DES.

RESULTS

Compared with CAD lesions, PAD lesions had (i) smaller mean vessel, plaque, and lumen volumes; (ii) twice the lesion length; (iii) greater maximum superficial calcium arc and plaque eccentricity (i.e. there was more concentric plaque) measured at the minimum lumen area site; (iv) calcium arc and plaque eccentricity were positively correlated to plaque burden in both PAD and CAD lesions; and (v) calcium arc and the presence of concentric plaque were greater in PAD compared with CAD independent of the degree of plaque burden.

CONCLUSION

Compared with CAD lesions, PAD lesions in a tibial or a peroneal artery were longer; had more concentric, diffuse, and calcified plaque; and had smaller vessel volumes.

Optical frequency-domain imaging findings to predict good stent expansion after rotational atherectomy for severely calcified coronary lesions

We aimed to evaluate the optical frequency-domain imaging (OFDI) findings after rotational atherectomy (RA) that predict good stent expansion for severely calcified coronary lesions. Fifty consecutive calcified lesions were subjected to RA under OFDI guidance. We performed OFDI just after RA and stenting. We measured the morphology of calcium after RA, and assessed how these factors influence stent expansion. The stent expansion index was defined as the minimum stent area divided by the average of the proximal and distal reference lumen areas. Minimum thickness of calcification in the intima after RA showed a significant negative correlation with stent expansion (r = - 0.53, P < 0.001), while calcium arc, length, and maximum thickness of calcification in the intima did not. Dissection after RA occurred in 22 lesions (44%), and the stent expansion index was significantly better in dissected lesions than in lesions without dissection (0.96 ± 0.08 vs. 0.82 ± 0.19, P = 0.002). Multiple regression analysis showed that the minimum thickness of calcification in the intima (standardized coefficient: - 0.451, P < 0.001) and dissection formation (standardized coefficient: 0.316, P = 0.011) were predictors of good stent expansion. Minimum of thickness of calcification in the intima and dissection formation were positively associated with good stent expansion after RA. In the clinical setting, achieving these two endpoints should be the aim of RA to ensure good stent expansion.

Orbital and rotational atherectomy during percutaneous coronary intervention for coronary artery calcification

Severe coronary artery calcification (CAC) increases the complexity of percutaneous coronary intervention (PCI) by inhibiting optimal stent expansion, leading to an increased risk of death, myocardial infarction, repeat revascularization, and stent thrombosis. Coronary atherectomy modifies and debulks calcified plaque to facilitate PCI. Although there is no clear consensus, and further studies are needed, the decision to perform atherectomy should be based upon the presence of fluoroscopic CAC or with the use of intravascular imaging. The management of CAC in the modern era relies on rotational and orbital atherectomy to prepare the lesion to facilitate stent delivery and optimal expansion. While the two technologies differ in equipment, technique, and mechanism of action, the available literature suggests similar efficacy and safety of the two systems, although head-to-head comparisons are limited. While rotational and orbital atherectomy have been shown to have excellent procedural success in terms of facilitating stent delivery, no system has been shown to reduce long-term major adverse cardiovascular events, although the definitive trial for orbital atherectomy has not been completed. Additional trials are needed to find the population who would derive the most benefit of atherectomy and to compare the two systems in a prospective manner.

The Role of Intracoronary Plaque Imaging with Intravascular Ultrasound, Optical Coherence Tomography, and Near-Infrared Spectroscopy in Patients with Coronary Artery Disease

The development of multiple diagnostic intracoronary imaging modalities has increased our understanding of coronary atherosclerotic disease. These imaging modalities, intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near-infrared spectroscopy (NIRS), have provided a method to study plaques and introduced the concept of plaque vulnerability. They are being increasingly used for percutaneous coronary intervention (PCI) optimization and are invaluable tools in research studying the pathophysiology of acute coronary syndrome (ACS), in-stent thrombosis and in-stent restenosis. IVUS has the ability to visualize the intracoronary lumen and the vessel wall and can be used to detect early atherosclerotic disease even in the setting of positive arterial remodeling. Studies supporting the use of IVUS to optimize stent deployment and apposition have shown a significant reduction in cardiovascular events. OCT provides even higher resolution imaging and near microscopic detail of plaques, restenoses, and thromboses; thus, it can identify the etiology of ACS. Ongoing trials are evaluating the role of OCT in PCI and using OCT to study stent endothelialization and neointimal proliferation. NIRS is a modality capable of localizing and quantifying lipid core burden. It is usually combined with IVUS and is used to characterize plaque composition. The benefits of NIRS in the setting of ACS have been limited to case reports and series. The utilization of all these intracoronary imaging modalities will continue to expand as their indications for clinical use and research grow. Studies to support their use for PCI optimization resulting in improved outcomes with potential to prevent downstream events are ongoing.

Current clinical applications of coronary optical coherence tomography

Optical coherence tomography (OCT) is an intra-coronary diagnostic technique that provides detailed imagings of blood vessels in the current cardiac catheterization laboratory. The higher resolution of OCT often provides superior delineation of each structure compared with intravascular ultrasound (IVUS), and it can reliably visualize the microstructure of normal and diseased arteries. The capabilities of OCT are well suited for the identification of calcified plaque and neointima formation after stent implantation. It has been reported that OCT-guided percutaneous coronary intervention (PCI) resulted in equivalent clinical and angiographic outcomes in comparison with IVUS-guided PCI. Recently, the three-dimensional reconstruction of OCT and a real-time point-to-point correspondence between coronary angiographic and OCT/OFDI images have been developed and provide useful information to PCI operators. The unique capabilities of OCT as an investigational tool for high-risk lesions will serve the cardiology community well, as it moves us toward a better understanding of atherosclerotic plaque. In addition, because of the development of new OCT technology, OCT has become a notable catheter-based imaging technology that can provide practical guidance for PCI in clinical settings.

A novel side branch protection technique in coronary stent implantation: Jailed Corsair technique

Side branch occlusion, which was one of the common complications in percutaneous coronary interventions, was closely associated with cardiac death and myocardial infarction. Clinical guidelines also support the importance of preservation of physiologic blood flow in SB during PCI to bifurcation lesions. In order to avoid side branch occlusion during stent implantation, we often performed the jailed wire technique, in which a conventional guide wire was inserted to the side branch before stent implantation to the main vessel. However, the jailed wire technique could not always prevent side branch occlusion. In this case report, we described a case of 72-year-old male suffering from angina pectoris. Coronary angiography revealed the diffuse calcified stenosis in the proximal and middle of left anterior descending coronary artery, and the large diagonal branch originated from the middle of the stenosis. To prevent side branch occlusion, we performed a novel side branch protection technique by using the Corsair microcatheter (Asahi Intecc, Nagoya, Japan). In this case report, we illustrated this "Jailed Corsair technique", and discussed the advantage compared to other side branch protection techniques such as the jailed balloon technique.

Predictors of acute scaffold recoil after implantation of the everolimus-eluting bioresorbable scaffold: an optical coherence tomography assessment in native coronary arteries

This study investigated the predictors of acute recoil after implantation of everolimus-eluting BRS based on optical coherence tomography (OCT). Thirty-nine patients (56 scaffolds) were enrolled. Acute absolute recoil by quantitative coronary angiography was defined as the difference between the mean diameter of the last inflated balloon (X) and the mean lumen diameter of BRS immediately after balloon deflation (Y). Acute percent recoil was defined as (X - Y) × 100/X. Plaque eccentricity (PE) and plaque composition (PC) were assessed by OCT. PC was classified into two different types: calcific (score = 1), fibrous and lipid (score = 0). Based on the mean acute scaffold recoil value of the present study, scaffolds were divided into two groups: the low acute recoil group (LAR, n = 34) and the high acute recoil group (HAR, n = 22). Acute percent and absolute recoil were 6.4 ± 3.0 % and 0.19 ± 0.11 mm. PE, PC score and scaffold/artery ratio were significantly higher in HAR than in LAR. In multivariate logistic regression analysis, PE > 1.49, PC score (score 1) and scaffold/artery ratio >1.07 were significant positive predictors for the occurrence of acute scaffold recoil (OR 10.7, 95 % CI 2.2-51.4, p < 0.01; OR 5.6, 95 % CI 1.9-22.0, p = 0.04; OR 12.4, 95 % CI 2.6-65.4, p < 0.01, respectively). Acute recoil of BRS is influenced by BRS sizing as well as OCT-derived plaque characteristics.

Impact of Calcification on Clinical Outcomes After Endovascular Therapy for Superficial Femoral Artery Disease

Purpose: To investigate whether the severity of lesion calcification assessed by the novel peripheral artery calcification scoring system (PACSS) was associated with clinical outcomes after endovascular therapy (EVT) for superficial femoral artery (SFA) lesions. Methods: A retrospective analysis was conducted of 394 consecutive patients (mean age 72±8 years; 290 men) with intermittent claudication [223 (57%) with diabetes, 81 (21%) on hemodialysis] who underwent successful EVT for de novo SFA lesions [length 152.1±95.7 mm; 199 (50%) TransAtlantic Inter-Society Consensus II class C/D] between January 2010 and December 2013. The patients were retrospectively categorized using the PACSS classification (grades 0–4: no visible calcification of the target lesion, unilateral wall calcification <5 cm, unilateral calcification ≥5 cm, bilateral wall calcification <5 cm, and bilateral calcification ≥5 cm, respectively). The main outcome was primary patency, while the secondary outcome measures were mortality and major adverse limb events [MALE: any intervention (repeat EVT or surgical revision) or major (above ankle) amputation]. Cox proportional hazards analysis was used to explore whether the PACSS classification was an independent predictor of clinical outcomes. Results are presented as the hazard ratio (HR) and 95% confidence interval (CI). Results: The distribution of PACSS grades was 0 in 54%, grade 1 in 16%, grade 2 in 12%, grade 3 in 9%, and grade 4 in 9%. The 2-year primary patency rates in these grades, respectively, were 70.0%, 66.6%, 72.1%, 55.6%, and 36.3% (p<0.001). After multivariate analysis, PACSS grade 4 (HR 2.74, 95% CI 1.56 to 4.83, p<0.001), diabetes (HR 1.52, 95% CI 1.06 to 2.20, p=0.022), lesion length (HR 1.04, 95% CI 1.01 to 1.07, p=0.006), and vessel diameter (HR 0.80, 85% CI 0.65 to 0.98, p=0.038) were associated with loss of primary patency. PACSS grade 4 was also associated with MALE and mortality (p=0.048 and 0.011, respectively). Bare metal stent use (HR 0.47, 95% CI 0.30 to 0.73, p<0.001) was positively associated with primary patency. Conclusion: PACSS grade 4 calcification was independently associated with clinical outcomes after EVT for de novo SFA lesions.

Impact of stent platform on longitudinal stent deformation: an in vivo frequency domain optical coherence tomography study

Recently, longitudinal coronary stent deformation has been highlighted as a possible cause of drug-eluting stent failure. Although bench tests and in vivo studies have demonstrated difference in longitudinal stent strength among the stents with different platforms, its clinical impact is still unknown. Furthermore, it is unknown if modified stent platform favorably affect the incidence of stent deformation. The aim of this study was to investigate the longitudinal deformation of the everolimus-eluting stents (EES) with different stent platforms by using frequency domain optical coherence tomography (FD-OCT). Seventy-eight lesions treated with EES (Xience Prime: n = 26, Promus element: n = 29, Promus premier: n = 23) were studied. After successful stent implantation, FD-OCT was performed and stent length was measured using three-dimensional reconstruction of the images in vivo. Percent longitudinal stent shortening (%SS) was defined as the in vivo stent length divided by nominal stent length. Longitudinal stent deformation was defined as  %SS > 10 %. Patients' and procedural characteristics were similar among 3 EESs. There was no difference in mean  %SS between Xience Prime, Promus Element and Promus Premier (1.0 ± 5.8, 2.9 ± 6.7 and 0.8 ± 3.7 %, p = 0.322). Incidence of the longitudinal stent deformation was significantly higher in Promus Element than the other stents (0, 13.8 and 0 %, p = 0.028). Incidence of longitudinal stent deformation was different between EESs with different stent platforms. Stent material, stent design and/or stent delivery balloon may affect longitudinal stent deformation.

Rotational atherectomy in very long lesions: Results for the ROTATE registry

BACKGROUND

Rotational atherectomy (RA) is relatively contraindicated in patients with lesions ≥25 mm of length. Aim of this study was to evaluate RA safety and efficacy in this subset of patients with new technology and devices.

METHODS AND RESULTS

From April 2002 to August 2013, the ROTATE registry included all consecutive patients undergoing RA in 8 centres. They were divided into shorter lesion group (SLG, lesions < 25 mm) and longer lesion group (LLG, lesions ≥ 25 mm). The angiographic success (AS) was the primary end point. Procedural complications (PC), a composite end point of procedural perforation, slow flow/no flow, and in-hospital major acute cardiovascular events (MACE), were secondary end points, along with death, nonfatal MI, target lesion revascularization, and MACE during follow-up. Sensitivity analysis was performed according to generation of DES. 1186 patients were included: 51.5% in SLG and 48.4% in LLG. Mean age was 70.4 ± 9.3 years, 64.5% were male. AS and PC did not differ between the two groups (93% vs 91%, p = 0.24 and 9.8 vs 9.4%, p = 0.84). During follow-up (27.6 ± 22.9 months), MACE did not differ between the two groups (28% vs 29.1%, p = 0.95). At multivariate analysis chronic kidney disease, male gender increased risk of MACE (HR 1.94, IQR 1.29-2.0, p = 0.01, HR 0.52, IQR 0.34-0.79, p = 0.01) while second-generation DES seemed protective (HR 0.53, IQR 0.31-0.88, p = 0.02). Data were confirmed at sensitivity analysis for second-generation DES (759 pts, 63.9%). No differences were found in this subpopulation between the two groups in term of AS, PC, and long-term MACE (93.6% vs 93.5%, p = 0.28, 11.9% vs 9.4%, p = 0.32 and 25.5% vs 23.9%, p = 0.72, respectively).

CONCLUSIONS

Treating coronary lesions ≥ 25 mm length with RA does not impact short- and long-term outcome, in particular, in patients with second-generation DES. © 2016 Wiley Periodicals, Inc.

Intravascular imaging of coronary calcification and its clinical implications

Calcium impacts the natural history and treatment of coronary artery disease in many ways. Intravascular imaging studies, mostly intravascular ultrasound, but more recently studies using optical coherence tomography, have been instrumental in increasing our understanding of the relationship between calcium and coronary atherosclerosis, the predictors, the natural history of this relationship, and the impact on treatment. On one hand, stable coronary lesions are associated with more calcium than unstable lesions; and the amount of calcium may affect the success of percutaneous coronary intervention. On the other hand, calcium correlates with plaque burden; unstable lesions are associated with focal calcium deposits; and calcific nodules are one of the morphologies of vulnerable plaque. This review focuses on more than 20 years of intravascular imaging studies of the relationship between calcium and coronary atherosclerosis.