Feasibility of morphological assessment of coronary artery calcification with electrocardiography-gated non-contrast computed tomography: a comparative study with optical coherence tomography

To investigate the feasibility of pre-procedural morphological assessment of coronary artery calcification in severely calcified lesions with electrocardiography (ECG)-gated non-contrast computed tomography (CT). Severely calcified coronary arteries in patients who underwent ECG-gated non-contrast CT prior to optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) were studied retrospectively. CT and OCT data were co-registered by marking landmark structures such as side branches and reviewed side by side with cross-sectional images. The maximum calcium angle (MCA) and presence of nodular calcification (NC) were evaluated. A total of 496 cross-sections in 16 lesions were included in this analysis. The Pearson correlation coefficient between CT- and OCT-derived MCA was 0.92 (p < 0.001). Bland-Altman plots of OCT-derived MCA in relation to CT-derived MCA showed a mean bias of 4.8 degrees with 95% limits of agreement of - 69.7 to 79.4 degrees. Sensitivity, specificity, and positive and negative predictive values of CT in identifying MCA > 270 degrees were 90.3%, 79.7%, 92.1%, and 97.4%, respectively. Sensitivity, specificity, and positive and negative predictive values of CT in identifying NC were 73.3%, 97.5%, 47.8%, and 99.2%, respectively. ECG-gated non-contrast coronary CT might be helpful to obtain detailed information of severe coronary artery calcification before PCI.

Comparison of clinical outcomes of intravascular ultrasound-calcified nodule between percutaneous coronary intervention with versus without rotational atherectomy in a propensity-score matched analysis

OBJECTIVES

This study aimed to compare the mid-term clinical outcomes of intravascular ultrasound (IVUS)-calcified nodules between percutaneous coronary intervention (PCI) with and without rotational atherectomy (RA).

BACKGROUND

There has been a debate whether to use RA for the revascularization of calcified nodule. Although RA can ablate the calcified structure within calcified nodule and may facilitate adequate stent expansion, RA may provoke severe coronary perforation, because calcified nodule typically shows eccentric calcification.

METHODS

We included 204 lesions with IVUS-calcified nodule, and divided into 73 lesions treated with RA (RA group) and 131 lesions without RA (non-RA group). After propensity-score matching, 42 lesions with RA (matched RA group) and 42 lesions without RA (matched non-RA group) were selected. We compared the clinical characteristics and outcomes between the 2 groups before and after propensity-score matching. The primary endpoint was ischemia-driven target vessel revascularization (TVR) within 1 year.

RESULTS

Acute lumen area gain on IVUS was comparable between the matched RA group and matched non-RA group (3.9 ± 2.1 mm2 vs. 3.4 ± 1.6 mm2, p = 0.18). The stent malapposition at calcified nodules was frequently observed in both groups. The ischemia-driven TVR was not different between the 2 groups before (p = 0.82) and after propensity score-matching (p = 0.87).

CONCLUSIONS

The use of RA could not reduce the incidence of ischemia-driven TVR in lesions with IVUS-calcified nodule. Our results do not support the routine use of RA for lesions with IVUS-calcified nodule.

Prediction of optimal debulking segments before rotational atherectomy based on pre-procedural intravascular ultrasound findings

This study evaluated whether intravascular ultrasound (IVUS) examination before rotational atherectomy (RA) can predict the optimal route of passage of the RA burr along the vessel. 30 patients with calcified lesions who underwent IVUS before and immediately after RA were enrolled. IVUS analyses were performed at the minimum lumen area (MLA) site and at 0.5 mm intervals. Each IVUS cross-section was divided into 4 quadrants around the center of the lumen, and pre- and post-RA IVUS cross-section images were merged. Of 1140 cross-sections, 498 (44%) contained debulked regions. When the guidewire and IVUS were located within the same quadrant, the debulked region were distributed within the same quadrant in 96% of cross-sections. The debulked region and the guidewire were distributed within the same quadrant in 81% and the debulked region and the IVUS in 72% of cross-sections, in case the guidewire and IVUS were located in different quadrants. When the guidewire and the IVUS was apart > 1.0 mm, the debulked regions were distributed within the same quadrant as the guidewire in 100% and the IVUS in 0% of cross-sections. The position of the guidewire rather than that of the IVUS catheter on pre-RA IVUS images could predict the course of the RA burr's passage, especially when the guidewire and IVUS catheter were located apart from each other.

Precision Percutaneous Coronary Intervention of a Complex Lesion

BACKGROUND

Balloon dilation and atherectomy have several limitations in the treatment of heavily calcific coronary lesions.

INTRODUCTION

Intravascular lithotripsy (IVL) is a state-of-the-art system that modifies severe calcific coronary plaques efficiently. In this paper, we report our experience with IVL in the context of a calcific in-stent chronic total occlusion.

CASE SUMMARY

A 75-year-old gentleman whose status was post percutaneous coronary intervention, with the deployment of two overlapping bare-metal stents in the mid-left anterior descending artery (LAD) 20 years ago, was admitted to our cardiac center for the elective intervention of in-stent chronic total occlusion (CTO) of LAD, which was performed using an antegrade wire escalation (AWE) technique. After recanalization of the CTO body, optical coherence tomography pullback confirmed a very high calcium score. Balloon dilatation attempts failed, so we proceeded with shockwave lithotripsy with successful full expansion of the 3.5-mm IVL balloon followed by a straightforward stent delivery. The procedure was complicated by distal wire perforation, which was handled in a timely manner with coil embolization. The patient's postoperative course was uneventful.

CONCLUSION

This case illustrates the feasibility and effectiveness of IVL that powerfully cracks coronary calcium while minimizing vessel wall trauma in the context of heavily calcific in-stent CTO. In our case, coronary perforation occurred in a small-caliber side branch, which was identified in a timely manner before hemodynamic compromise and treated successfully straight away with coil embolization.

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.

Safety and effectiveness of coronary intravascular lithotripsy in eccentric calcified coronary lesions: a patient-level pooled analysis from the Disrupt CAD I and CAD II Studies

BACKGROUND

The aim of this study was to assess the safety and effectiveness of intravascular lithotripsy (IVL) in treating eccentric calcified coronary lesions.

METHODS

Between December 2015 and March 2019, 180 patients were enrolled in the Disrupt CAD I and CAD II studies across 19 sites in 10 countries. Patient-level data were pooled from these two studies (n = 180), within which 47 eccentric lesions (26%) and 133 concentric lesions were identified.

RESULTS

Clinical success, defined as residual stenosis < 50% after stenting and no in-hospital MACE, was similar between the eccentric and concentric cohorts (93.6% vs. 93.2%, p = 1.0). There were no perforations, abrupt closure, slow flow or no reflow events observed in either group, and there were low rates of flow-limiting dissections (Grade D-F: 0% eccentric, 1.7% concentric; p = 0.54). Final acute gain and percent residual stenosis were similar between the two groups. Final residual stenosis of 8.6 ± 9.8% in eccentric and 10.0 ± 9.0% (p = 0.56) in concentric stenosis confirms the significant effect of IVL in calcified coronary lesions.

CONCLUSION

In this first report from a pooled patient-level analysis of coronary IVL from the Disrupt CAD I and CAD II studies, IVL use was associated with consistent improvement in procedural and clinical outcomes in both eccentric and concentric calcified lesions.

Efficacy of coronary imaging on bifurcation intervention

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

Simulation-Driven Machine Learning for Predicting Stent Expansion in Calcified Coronary Artery

In this work, we integrated finite element (FE) method and machine learning (ML) method to predict the stent expansion in a calcified coronary artery. The stenting procedure was captured in a patient-specific artery model, reconstructed based on optical coherence tomography images. Following FE simulation, eight geometrical features in each of 120 cross sections in the pre-stenting artery model, as well as the corresponding post-stenting lumen area, were extracted for training and testing the ML models. A linear regression model and a support vector regression (SVR) model with three different kernels (linear, polynomial, and radial basis function kernels) were adopted in this work. Two subgroups of the eight features, i.e., stretch features and calcification features, were further assessed for the prediction capacity. The influence of the neighboring cross sections on the prediction accuracy was also investigated by averaging each feature over eight neighboring cross sections. Results showed that the SVR models provided better predictions than the linear regression model in terms of bias. In addition, the inclusion of stretch features based on mechanistic understanding could provide a better prediction, compared with the calcification features only. However, there were no statistically significant differences between neighboring cross sections and individual ones in terms of the prediction bias and range of error. The simulation-driven machine learning framework in this work could enhance the mechanistic understanding of stenting in calcified coronary artery lesions, and also pave the way toward precise prediction of stent expansion.

Association of the long fluoroscopy time with factors in contemporary primary percutaneous coronary interventions

BACKGROUND

Since the long fluoroscopy time in primary PCI for ST-segment elevation myocardial infarction (STEMI) could be an indicator of delayed reperfusion, it should be important to recognize which types of lesions require longer fluoroscopy-time in primary PCI. The purpose of this study was to investigate the association of the long fluoroscopy-time with clinical factors in primary percutaneous coronary interventions (PCI).

METHODS

A total of 539 patients who underwent primary PCI were divided into the conventional fluoroscopy-time group (Q1-Q4: n = 434) and the long fluoroscopy-time group (Q5: n = 105) according to the quintile of the total fluoroscopy time in primary PCI. Univariate and multivariate logistic regression analyses were performed to find associations between clinical variables and the long fluoroscopy-time.

RESULTS

In univariate logistic regression analysis, prevalence of diabetes mellitus, hemodialysis, and previous CABG were significantly associated with the long fluoroscopy-time. In addition, complex lesion characteristics such as lesion length, lesion angle, tortuosity, and calcification were associated with the long fluoroscopy-time. In multivariable logistic regression analysis, lesion length [per 10 mm incremental: odds ratio (OR) 1.751, 95% confidence interval (CI) 1.397-2.195, P<0.001], moderate-excessive tortuosity (vs. mild tortuosity: OR 4.006, 95% CI 1.498-10.715, P = 0.006), and moderate to severe calcification (vs. none-mild calcification: OR 1.865, 95% CI 1.107-3.140, P = 0.019) were significantly associated with the long fluoroscopy-time.

CONCLUSIONS

In primary PCI for STEMI, diffuse long lesion, tortuosity, and moderate-severe calcification were associated with the long fluoroscopy-time. These complex features require special attention to reduce reperfusion time in primary PCI.

Management of Calcific Coronary Artery Lesions: Is it Time to Change Our Interventional Therapeutic Approach?

Patients with obstructive coronary lesions with a high calcium content (LHCC) have an exaggerated clinical risk, because the presence of calcification is associated with more extensive coronary atheroma and higher burden of comorbidities. Treatment of LHCC using percutaneous techniques is complex because of an increased risk of incomplete lesion preparation with suboptimal stent deployment and higher rates of acute and chronic stent failure. Rotational atherectomy has been the predominant technology for treatment of high-grade LHCC, but novel devices/technologies have entered clinical practice. It seems likely that combining enhanced intravascular imaging, which allows definition of the patterns of calcification with these new technologies, will herald a change in procedural algorithms for treatment of LHCC. This review provides an overview about LHCC with special focus on existing and emergent technologies. We also provide a proposed procedural algorithm to facilitate optimal use of technology according to specific features of LHCC and coronary anatomy.

Optical coherence tomography-guided versus intravascular ultrasound-guided rotational atherectomy in patients with calcified coronary lesions

AIMS

We aimed to evaluate whether optical coherence tomography (OCT)-guided rotational atherectomy (RA) improves stent expansion and clinical outcomes compared to intravascular ultrasound (IVUS)-guided RA.

METHODS AND RESULTS

From our database, we identified 247 de novo calcified coronary lesions that underwent RA between September 2013 and December 2017. Of these, lesions with no intravascular imaging data (n=11), poor image quality (n=7), balloon angioplasty alone (n=16), and complications (two burr entrapments, two perforations) were excluded. Finally, 88 and 121 lesions that underwent OCT-guided and IVUS-guided RA, respectively, were included in the study. The primary endpoint of the present study was percent stent expansion. Burr upsizing was more frequently performed (55% vs 32%, p=0.001) and the final burr size was significantly larger (1.75 [1.50-1.75] vs 1.50 [1.50-1.75] mm, p<0.001) in the OCT-guided RA group. Percent stent expansion was significantly larger in the OCT-guided RA group (83±15% vs 72±16%, p=0.0004). Although TLR at one year was lower in the OCT-guided RA group, there was no statistical difference (6.8% vs 11.6%, p=0.25).

CONCLUSIONS

OCT-guided RA for calcified coronary lesions resulted in larger percent stent expansion compared to IVUS-guided RA. OCT-guided RA may be ideal for treating calcified coronary lesions.

Intravascular ultrasound to guide left main stem intervention: a NOBLE trial substudy

AIMS

We aimed to investigate the association between the use and findings of IVUS with clinical outcomes in the PCI arm of a randomised trial of LMS PCI.

METHODS AND RESULTS

The NOBLE trial randomised patients with LMS disease to treatment by PCI or CABG. Of 603 patients treated by PCI, 435 (72%) underwent post-PCI IVUS assessment, 224 of which were analysed in a core laboratory. At five years, the composite of MACCE was 18.9% if post-PCI IVUS was performed versus 25.0% if it was not performed (p=0.45, after adjustment). Overall repeat revascularisation was not reduced (10.6% vs 16.5%, p=0.11); however, LMS TLR was (5.1% vs 11.6%, p=0.01) if IVUS was used. For comparison of stent expansion, LMS MSA was split into tertiles. We found no significant difference in MACCE, death, myocardial infarction or stent thrombosis between tertiles. There was a significant difference between the lower and upper tertiles for repeat revascularisation (17.6% vs 5.2%, p=0.02) and LMS TLR (12.2% vs 0%, p=0.002).

CONCLUSIONS

Post-PCI IVUS assessment and adequate stent expansion are not associated with reduced MACCE; however, there is an association with reduced LMS TLR. The use of intracoronary imaging to prevent stent underexpansion in LMS PCI is likely to improve outcomes.

Evaluation of safety and efficacy of coronary intravascular lithotripsy for treatment of severely calcified coronary stenoses: Design and rationale for the Disrupt CAD III trial

Coronary calcification limits optimal stent expansion and apposition and worsens safety and effectiveness outcomes of percutaneous coronary intervention (PCI). Current ablative technologies that modify calcium to optimize stent deployment are limited by guidewire bias and periprocedural complications related to atheroembolization, coronary dissection, and perforation. Intravascular lithotripsy (IVL) delivers pulsatile ultrasonic pressure waves through a fluid-filled balloon into the vessel wall to modify calcium and enhance vessel compliance, reduce fibroelastic recoil, and decrease the need for high-pressure balloon (barotrauma) inflations. IVL has been used in peripheral arteries as stand-alone revascularization or as an adjunct to optimize stent deployment. STUDY DESIGN AND OBJECTIVES: Disrupt CAD III (clinicaltrials.gov identifier: NCT03595176) is a prospective, multicenter, single-arm study designed to assess safety and efficacy of the Shockwave coronary IVL catheter to optimize coronary stent deployment in patients with de novo calcified coronary stenoses. The primary safety end point is freedom from major adverse cardiovascular events (composite of cardiac death, myocardial infarction, and target vessel revascularization) at 30 days compared to a prespecified performance goal. The primary effectiveness end point is procedural success without in-hospital major adverse cardiovascular events. Enrollment will complete early in 2020 with clinical follow-up ongoing for 2 years. CONCLUSION: Disrupt CAD III will evaluate the safety and effectiveness of the Shockwave coronary IVL catheter to optimize coronary stent deployment in patients with calcified coronary stenoses.

Real-World Experience With a Tapered Biodegradable Polymer-Coated Sirolimus-Eluting Stent in Patients With Long Coronary Artery Stenoses

Background

Treatment of long coronary stenoses (LCS) with long tapered drug-eluting stents (LT-DES) would offer clinical and economic benefits. However, the feasibility of an interventional strategy based upon the systematic LCS treatment with an LT-DES has not been evaluated so far.

Methods

We performed a multicenter prospective study including consecutive patients with: 1) An LCS > 25 mm at coronary angiography; 2) An attempt to fix the LCS with a single BioMime Morph™ stent, a novel LT-DES available from 30 to 60 mm long. The primary efficacy endpoint was procedural success. The secondary safety endpoints were post-procedural TIMI3 flow, stent detachment during delivery, acute stent thrombosis and in-hospital mortality.

Results

From February 2017 to March 2018, we recorded 272 patients with an LCS and an attempt to deploy an LT-DES during percutaneous coronary intervention (PCI) (69.3 ± 11.4 years, 75.7% males, 25.7% diabetic and 43.8% with acute coronary syndromes, mean LCS length 48.8 ± 9.5 mm). LT-DES deployment was successful in 262 patients (96.3%), and failure occurred without stent detachment or other complications. Final TIMI3 flow was present in 270 (99.3%) patients. In-hospital death occurred in five patients (1.8%), with no case of acute stent thrombosis, recurrent myocardial infarction or repeated revascularization.

Conclusion

In this real-world study, a strategy of fixing LCS with a single LT-DES was feasible and safe, with a high rate of procedural success and a low rate of in-hospital complications. More extensive randomized studies are warranted to assess the potential clinical and economic benefits of LT-DES.

Additional debulking efficacy of low-speed rotational atherectomy after high-speed rotational atherectomy for calcified coronary lesion

We aimed to evaluate the additional debulking efficacy of low-speed rotational atherectomy (RA) after high-speed RA by using intravascular imaging. A total of 22 severe calcified coronary lesions in 19 patients (age, 74 ± 10 years; 74% male) were retrospectively analyzed. All of these lesions underwent RA under optical coherence tomography (OCT) or optical frequency domain imaging (OFDI) guidance. At first, we performed high-speed RA with 220,000 rpm until the reduction of rotational speed disappeared; then, low-speed RA with 120,000 rpm using the same burr size was performed. OCT or OFDI was performed after both high-speed and low-speed RAs, and the minimum lumen area were compared. The initial and final burr sizes of high-speed RA were 1.5 (1.5-1.75) and 1.75 (1.5-2.0) mm, respectively. The number of sessions, total duration time, and maximum decreased rotational speed during high-speed RA were 11 ± 5 times, 113 ± 47 s, and 4000 (3000-5000) rpm, respectively. During low-speed RA, the number of sessions, total duration time, and maximum reduction of rotational speed were 3 ± 1 times, 32 ± 11 s, and 1000 (0-2000) rpm, respectively. The minimum lumen area was similar between after high-speed and after low-speed RA [2.61 ± 1.03 mm² (after high-speed RA) vs. 2.65 ± 1.00 mm² (after low-speed RA); P = 0.91]. Additional low-speed RA immediately after sufficient debulking by high-speed RA was not associated with increased lumen enlargement. There was no clinical efficacy of low-speed RA after high-speed RA.

Optical Coherence Tomography-Based Modeling of Stent Deployment in Heavily Calcified Coronary Lesion

In this work, a heavily calcified coronary artery model was reconstructed from optical coherence tomography (OCT) images to investigate the impact of calcification characteristics on stenting outcomes. The calcification was quantified at various cross sections in terms of angle, maximum thickness, and area. The stent deployment procedure, including the crimping, expansion, and recoil, was implemented. The influence of calcification characteristics on stent expansion, malapposition, and lesion mechanics was characterized. Results have shown that the minimal lumen area following stenting occurred at the cross section with the greatest calcification angle. The calcification angle constricted the stretchability of the lesion and thus resulted in a small lumen area. The maximum principal strain and von Mises stress distribution patterns in both the fibrotic tissue and artery were consistent with the calcification profiles. The radially projected region of the calcification tends to have less strain and stress. The peak strain and stress of the fibrotic tissue occurred near the interface with the calcification. It is also the region with a high risk of tissue dissection and strut malapposition. In addition, the superficial calcification with a large angle aggregated the malapposition at the middle of the calcification arc. These detailed mechanistic quantifications could be used to provide a fundamental understanding of the role of calcification in stent expansions, as well as to exploit their potential for enhanced pre- and post-stenting strategies.

Characteristics of abnormal post-stent optical coherence tomography findings in hemodialysis patients

AIM

Clinical outcomes after percutaneous coronary intervention (PCI) in hemodialysis (HD) patients are significantly worse than those in non-HD patients. Optical coherence tomography (OCT) is a high resolution imaging modality and provides a detailed assessment of post-interventional abnormal findings that influence worse clinical outcomes. However, little is known about the abnormal post-stent OCT findings in HD patients. Therefore, in this study, we compared the abnormal post-stent OCT findings between HD and non-HD patients.

METHODS

One hundred thirty-nine consecutive OCT guided PCI (21 lesions in HD patients and 118 lesions in non-HD patients) were enrolled. We compared the post-stent OCT findings, including the edge dissections, under expansion index (minimum stent area/mean reference area), and stent eccentricity index (minimum stent diameter/maximum stent diameter) between HD and non-HD patients. We also compared the device-oriented clinical events (DoCEs) at 8 months of follow up.

RESULTS

There was a significantly higher prevalence of distal edge dissections (16.7% vs. 2.8%, P = 0.011) in HD patients. HD patients had a significantly lower under expansion index (0.76 ± 0.21 vs. 0.85 ± 0.14, P = 0.029) and stent eccentricity index (0.82 ± 0.09 vs. 0.88 ± 0.18, P = 0.018). The cumulative rate of DoCEs was significantly higher in the HD patients (23.8% vs. 5.2%, P = 0.013).

CONCLUSIONS

A higher prevalence of distal edge dissections, under expansion and stent eccentricity were detected by the detailed OCT findings in HD patients.

Assessment of the healing process after percutaneous implantation of a cardiovascular device: a systematic review

The healing process, occurring after intra-cardiac and intra-vascular device implantation, starts with fibrin condensation and attraction of inflammatory cells, followed by the formation of fibrous tissue that slowly covers the device. The duration of this process is variable and may be incomplete, which can lead to thrombus formation, dislodgement of the device or stenosis. To better understand this process and the neotissue formation, animal models were developed: small (rats and rabbits) and large (sheep, pigs, dogs and baboons) animal models for intra-vascular device implantation; sheep and pigs for intra-cardiac device implantation. After intra-vascular and intra-cardiac device implantation in these animal models, in vitro techniques, i.e. histology, which is the gold standard and scanning electron microscopy, were used to assess the device coverage, characterize the cell constitution and detect complications such as thrombosis. In humans, optical coherence tomography and intra-vascular ultrasounds are both invasive modalities used after stent implantation to assess the structure of the vessels, atheroma plaque and complications. Non-invasive techniques (computed tomography and magnetic resonance imaging) are in development in humans and animal models for tissue characterization (fibrosis), device remodeling evaluation and device implantation complications (thrombosis and stenosis). This review aims to (1) present the experimental models used to study this process on cardiac devices; (2) focus on the in vitro techniques and invasive modalities used currently in humans for intra-vascular and intra-cardiac devices and (3) assess the future developments of non-invasive techniques in animal models and humans for intra-cardiac devices.

Lesion Preparation with Orbital Atherectomy

Despite significant improvements in stent design, severe coronary calcification continues to impede adequate stent expansion and is associated with worse clinical outcomes. Angiography is limited in its ability to detect and comprehensively characterise calcified plaque. Intravascular imaging provides information on lesion morphology guiding appropriate treatment strategies. Orbital atherectomy allows for lesion preparation of severely calcified plaque prior to stent implantation. Utilising a unique mechanism of action incorporating centrifugal forces, a standard 1.25 mm eccentrically mounted and diamond-coated burr orbits bi-directionally to ablate calcified plaque. Lesion preparation with orbital atherectomy allows for modification of calcified plaque to facilitate stent expansion.

Intravascular Lithotripsy in Calcified Coronary Lesions

Background:

Optimal plaque preparation of calcified coronary lesions is key to prevent stent failure. The purpose of this study was to determine the strategy success and safety of intravascular lithotripsy (IVL) in calcified lesions of an all-comers cohort.

Methods:

Patients with calcified coronary lesions were screened in 3 centers. Seventy-one patients were eligible for IVL. Patients were assigned to (group A) primary IVL therapy for patients with calcified de-novo lesions (n=39 lesions), (group B) secondary IVL therapy for patients with calcified lesions in which noncompliant balloon dilatation failed (n=22 lesions), and (group C) tertiary IVL therapy in patients with stent underexpansion after previous stenting (n=17 lesions). Primary end point was strategy success (stent expansion with <20% in-stent residual stenosis) and safety outcomes (procedural complications, in-hospital major adverse cardiovascular event).

Results:

Seventy-eight calcified lesions were treated using the Shockwave C 2 balloon. Mean diameter stenosis of calcified lesions was 71.8±13.1% at baseline, decreased to 45.1±17.4% immediately after IVL, and to 17.5±15.2% after stenting. Mean minimal lumen diameter was 1.01±0.49 mm at baseline and increased to 1.90±0.61 after IVL, and to 2.88±0.56 mm after stenting. The primary end point of strategy success was reached in 84.6% (group A), 77.3% (group B), and 64.7% (group C). Device delivery and IVL treatment were possible in all lesions. Four type b dissections were observed without further sequelae. No patient suffered from in-hospital major adverse cardiovascular event. Seven Shockwave balloons ruptured during treatment without any sequelae.

Conclusions:

IVL provides a valid strategy for lesion preparation in severely calcified coronary lesions with high success rate, low procedural complications, and low major adverse cardiovascular event rates.

The Coronary Intravascular Lithotripsy System

Calcified lesions often mean percutaneous intervention results are suboptimal and increase the risk of procedural complications and future adverse events. Available plaque-modifying devices rely on tissue compression or debulking, with the intention of fracturing calcium and facilitating optimal stent deployment. In contrast, coronary intravascular lithotripsy delivers unfocused, circumferential, pulsatile mechanical energy to safely disrupt the calcium within the target lesion. The present review summarises the evidence available so far on this therapy and includes a practical description of the components and function of the Shockwave Intravascular Lithotripsy System (Shockwave Medical).

Intracoronary Lithotripsy for the Treatment of Calcified Plaque

Intravascular lithotripsy facilitates percutaneous coronary intervention of lesions with severe calcification by using high-pressure ultrasonic energy. It is the newest adjunctive tool for calcium modification and is showing promise as its users gather more experience and it becomes readily available worldwide. This article reviews intravascular lithotripsy technology, the evidence in the literature, and the advantages and disadvantages compared with other forms of calcium modification, and discusses its role in specific subsets of coronary lesions. It concludes with a discussion about the future direction of research involving this new technology as its role within percutaneous cardiac procedures becomes more defined.

Safety and Effectiveness of Coronary Intravascular Lithotripsy for Treatment of Severely Calcified Coronary Stenoses

Background:

The feasibility of intravascular lithotripsy (IVL) for modification of severe coronary artery calcification (CAC) was demonstrated in the Disrupt CAD I study (Disrupt Coronary Artery Disease). We next sought to confirm the safety and effectiveness of IVL for these lesions.

Methods:

The Disrupt CAD II study was a prospective multicenter, single-arm post-approval study conducted at 15 hospitals in 9 countries. Patients with severe CAC with a clinical indication for revascularization underwent vessel preparation for stent implantation with IVL. The primary end point was in-hospital major adverse cardiac events (cardiac death, myocardial infarction, or target vessel revascularization). An optical coherence tomography substudy was performed to evaluate the mechanism of action of IVL, quantifying CAC characteristics and calcium plaque fracture. Independent core laboratories adjudicated angiography and optical coherence tomography, and an independent clinical events committee adjudicated major adverse cardiac events.

Results:

Between May 2018 and March 2019, 120 patients were enrolled. Severe CAC was present in 94.2% of lesions. Successful delivery and use of the IVL catheter was achieved in all patients. The post-IVL angiographic acute luminal gain was 0.83±0.47 mm, and residual stenosis was 32.7±10.4%, which further decreased to 7.8±7.1% after drug-eluting stent implantation. The primary end point occurred in 5.8% of patients, consisting of 7 non–Q-wave myocardial infarctions. There was no procedural abrupt closure, slow or no reflow, or perforations. In 47 patients with post-percutaneous coronary intervention optical coherence tomography, calcium fracture was identified in 78.7% of lesions with 3.4±2.6 fractures per lesion, measuring 5.5±5.0 mm in length.

Conclusions:

In patients with severe CAC who require coronary revascularization, IVL was safely performed with high procedural success and minimal complications and resulted in substantial calcific plaque fracture in most lesions.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03328949.

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.

Effect of cutting balloon after rotational atherectomy in severely calcified coronary artery lesions as assessed by optical coherence tomography

OBJECTIVES

Using optical coherence tomography (OCT), we evaluated the effect of a cutting balloon (CB) compared with a conventional balloon after rotational atherectomy (RA) and before stenting in severely calcified coronary lesions.

BACKGROUND

A CB is designed to create discrete incisions to facilitate fracture of severely calcified plaque.

METHODS

OCT was performed preintervention (if possible), post-RA, and poststent implantation. RA modification of calcium was defined as a polished, concave, round-shaped surface. Calcium fracture was defined as a break in the calcium plate. The effects of calcium modification and stent expansion between CB (n = 18) versus conventional balloon (n = 23) following RA were compared.

RESULTS

Median patient age was 72 years with 24% on hemodialysis. The amount of calcium and the length of RA modification were comparable between the CB and conventional balloon groups. Final poststent OCT showed that the number and thickness of calcium fracture were greater after CB versus conventional balloon, resulting better stent expansion (78.9% [IQR: 72.4-88.1] vs. 66.7% [IQR: 55.0-76.7], p < 0.01). In the multivariable model, after adjusting for the amount of calcium, CB use was an independent predictor of the presence of calcium fracture (odds ratio 30.0; 95% confidence interval 2.7-994.1, p = 0.004) and an independent predictor for greater stent expansion (regression coefficient 7.4; 95% confidence interval 0.5-14.3, p = 0.04).

CONCLUSION

In severely calcified lesions calcium fracture was more often associated with RA followed by CB compared with RA followed by conventional balloon predilation before stenting. CB use was also a determinant of greater stent expansion.

Association between debulking area of rotational atherectomy and platform revolution speed-Frequency domain optical coherence tomography analysis

OBJECTIVES

In this study, we sought to investigate the association between revolution speed of rotational atherectomy (RA) and debulking area assessed by frequency domain-optical coherence tomography (FD-OCT).

BACKGROUND

The number of patients with severe calcified coronary artery disease requiring treatment with calcium ablation, such as RA, is increasing. However, there is little evidence available regarding the association between debulking area and revolution speed during RA.

METHODS

We retrospectively investigated 30 consecutive severely calcified coronary lesions in 29 patients who underwent RA under FD-OCT guidance. The association between preset revolution speed of RA and burr size-corrected debulking area of the calcified lesion was evaluated using a multivariable regression model with nonlinear restricted-cubic-spline, which can help assess nonlinear associations between variables.

RESULTS

The median age of study participants was 73 years (quartile 65-78); 82.8% were male. The median burr size was 1.5 mm (1.5-1.75); median total duration of ablation was 120 s (100-180). FD-OCT revealed that the post-procedural minimum lumen area increased significantly from 1.64 mm² (1.40-2.09) to 2.45 mm² (2.11-2.98) (p < .001). In addition, the burr size-corrected debulking area increased significantly as the preset revolution speed decreased (p = .018), especially when the revolution speed was less than 150,000 rpm. This result implies that additional lumen gain will be obtained by decreasing rpm when the burr speed is set at <150,000 rpm.

CONCLUSIONS

FD-OCT demonstrated that RA with lower revolution speed, below 150,000 rpm, has the potential to achieve greater calcium debulking effect in patients with severe calcified coronary lesions.

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.

Orbital Atherectomy: A Comprehensive Review

Successful percutaneous coronary intervention (PCI) can be challenging in the presence of heavily calcified lesions. Severely calcified lesions are associated with worse clinical outcomes. Recognition of calcification is important before stenting to ensure adequate stent expansion can be attained. Orbital atherectomy is a safe and effective method to ablate calcified plaque. Lesion preparation through plaque modification with orbital atherectomy before stent implantation can help to optimize the results of PCI in these complex lesions.

Intravascular Ultrasound Assessment of In-Stent Restenosis in Saphenous Vein Grafts

Outcomes after percutaneous coronary interventions (PCI) in saphenous vein grafts (SVG) are inferior compared with native coronary arteries, but the mechanisms of SVG in-stent restenosis (ISR) have not been well-described. Thus, we aimed to evaluate the patterns of SVG ISR using intravascular ultrasound (IVUS) in 54 SVG ISR lesions. Stent underexpansion was defined as minimum stent area (MSA) <5 mm². The time from stent implantation to presentation with ISR (9 BMS, 18 first-generation DES, and 27 second-generation DES) was 3.7 ± 3.0 years. IVUS-defined ISR patterns were categorized as mechanical (33%) or biological (67%). Mechanical patterns comprised 10 cases of stent underexpansion (MSA = 4.2 ± 0.9 mm²), 6 stent fractures or deformations, and 2 uncovered aorto-anastomotic lesions. Biological patterns comprised 19 cases of neoatherosclerosis, 13 excessive neointimal hyperplasia (NIH, 65 ± 11%), and 4 thrombi. Compared with biological patterns of ISR, mechanical patterns were more frequently located at the SVG anastomosis (72% vs 39%, p = 0.04) and at the SVG hinge motion site (55% vs 21%, p = 0.02). Although patients with mechanical patterns of ISR presented earlier than those with biological patterns (2.3 vs 4.4 years, p = 0.009), 61% of them were diagnosed >1 year after stent implantation. In conclusion, SVG ISR is dominated by biological patterns including neoatherosclerosis. Mechanical patterns of SVG ISR are associated with earlier presentation and location at graft anastomosis or hinge motion site.

Comparison of Balloon Angioplasty and Stent Implantation for Femoropopliteal Disease According to Patient and Lesion Subgroup

Background: Little is known about the superiority of balloon angioplasty vs. stent implantation for femoropopliteal (FP) lesions according to subgroup.

Methods and Results: This study involved 1,018 de novo (balloon angioplasty, n=462; stent implantation, n=556) and 114 in-stent restenosis (ISR) FP lesions (balloon angioplasty, n=69; stent implantation, n=45) treated with endovascular therapy. For de novo FP lesions, the 3-year primary patency rate was significantly better with stent implantation than with balloon angioplasty (61% vs. 69%, log-rank P=0.001), but it was similar for ISR FP lesions (40% vs. 43%, log-rank P=0.83). For de novo FP lesions, stent implantation was favorable in all subgroups except for female sex (hazard ratio [HR], 0.92; 95% CI: 0.65–1.31, P=0.66), critical limb ischemia (CLI; HR, 0.70; 95% CI: 0.46–1.06, P=0.10), calcified lesion (HR, 0.81; 95% CI: 0.46–1.39, P=0.44), and poor tibial run-off (HR, 0.86; 95% CI: 0.59–1.25, P=0.42) subgroups. No difference was found between the 2 treatment strategies for ISR FP lesions in the majority of subgroups. Stent implantation, however, was favorable in totally occluded ISR FP lesions (HR, 0.45; 95% CI: 0.21–1.01, P=0.05).

Conclusions: The primary patency rate in de novo FP lesions for the 2 treatment strategies was similar in the female, calcified lesion, CLI, and poor tibial run-off subgroups. Stent implantation was superior to balloon angioplasty for totally occluded ISR FP lesions.

When Calcium Gets Tough, the Tough Cardiologist Starts to Play …

Coronary calcification is a hard challenge for the interventional cardiologist, as it is associated with incomplete stent expansion and frequently stent failure. In recent years, innovative techniques, such as rotational atherectomy, have been developed to treat coronary calcification. However, these are burdened with an increased procedural risk. We report the case of a 60-year-old Caucasian man treated 1 month before at another center with primary coronary angioplasty and stenting of the ramus intermedius for coronary syndrome. Coronary angiography showed a critical stenosis of the left main coronary artery as well as critical calcified stenosis of the left anterior descending artery and the diagonal branch. Coronary calcification was treated with rotational atherectomy that preceded the angioplasty and stenting. Because of persistence of the symptomatology, coronary angiography was repeated 1 month later and showed a critical calcified restenosis of the ramus intermedius at the site of the previous stenting. Considering the high risk of traditional atherectomy, we performed lithotripsy-enhanced disruption of calcium beyond the stents with the Shockwave Coronary Lithoplasty System. The Shockwave Coronary Lithoplasty System has been introduced recently in order to treat calcified coronary lesions with greater safety. The procedure allows most calcified coronary lesions to be treated with simplicity and safety. This system employs sound waves, similar to those used for treating kidney stones, to crush the calcified lesions. We present the first case described to date in whom this technique was successfully used to treat calcified restenosis in a previous stent.

IMPACT OF CALCIUM QUANTIFICATIONS ON STENT EXPANSIONS

Severely calcified plaque is of great concern when planning and implementing a stenting intervention. In this work, computational models were developed to investigate the influence of calcium characteristics on stenting outcomes. The commonly used clinical measurements of calcium (i.e., the arc angle, maximum thickness, length, and volume) were varied to estimate stenting outcomes in terms of lumen gain, stent underexpansion, strut malapposition, and stress or strain distributions of the stenotic lesion. Results have shown that stenting outcomes were most sensitive to the arc angle of the calcium. A thick calcium with a large arc angle resulted in poor stenting outcomes, such as severe stent underexpansion, D-shaped lumen, increased strut malapposition, and large stresses or strains in the plaque. This was attributed to the circumferential stretch of the tissue. Specifically, the non-calcium component was stretched significantly more than the calcium. The circumferential stretch ratios of calcium and non-calcium component were approximately 2.35 and 1.44, respectively, regardless of calcium characteristics. In addition, the peak stress or strain within the artery and non-calcium component of the plaque occurred at the area adjacent to calcium edges (i.e., the interface between the calcium and the non-calcium component) coincident with the location of peak malapposition. It is worth noting that the calcium played a protective role for the artery underneath, which was at the expense of the overstretch and stress concentrations in the other portion of the artery.

Distal embolization of coronary calcified nodule after rotational atherectomy

A 62-year-old man with effort angina underwent percutaneous coronary intervention in our hospital. The target lesion was severely calcified at the mid part of the right coronary artery. Pre-procedural intravascular imaging and optical frequency domain imaging showed a calcified nodule at the lesion. We performed rotational atherectomy with a 2.0 mm burr and observed an increase in the lumen area; however, a large amount of calcified nodule persisted. We decided to perform rotational atherectomy with a burr size of 2.25 mm; however, distal embolization of the calcified nodule occurred. We failed to retrieve the embolus; hence, we performed balloon dilatation with a 2.0-mm balloon, which was successfully performed. Yet, the lesion with the embolus immediately recoiled. Finally, a drug-eluting stent was implanted in both the distal lesion with the embolus and the lesion with the calcified nodule. Final coronary angiography showed good results. We confirmed good stent expansion and that calcified nodule was compressed outside the stent. Atherectomy of a calcified nodule is effective at achieving sufficient stent expansion and reducing the risk of vessel perforation. However, we experienced distal embolization of the calcified nodule at the time of rotational atherectomy and so distal embolization should be considered at the time of treatment of calcified nodule.

Intravascular ultrasound assessment of the effects of rotational atherectomy in calcified coronary artery lesions

We sought to clarify intravascular ultrasound (IVUS) features of rotational atherectomy (RA) of calcified lesions. IVUS was performed post-RA and post-stent in 38 lesions and analyzed every 1 mm. Pre-intervention IVUS was performed when the IVUS catheter crossed the lesion (n = 11). Calcium Index was average calcium angle multiplied by calcium length. We compared lowest (n = 13), middle (n = 13), and highest (n = 12) Calcium Index tertiles. Reverberations (multiple reflections from calcium) with a concave-shaped lumen in the post-RA IVUS were considered to represent RA-related calcium modification. Newly visible perivascular tissue through a previously solid arc of calcium in the post-stent IVUS was also evaluated. Comparing the pre and post-RA IVUS, maximum reverberation angle, and length increased significantly after RA (angle, from 45° [31, 67] to 96° [50, 148], p = 0.003; length, from 4.0 mm [2.0, 6.0] to 8.0 mm [4.0, 14.0], p = 0.005). In the post-RA IVUS, reverberations had a larger angle in the middle and highest Calcium Index tertiles (lowest, 91° [64, 133]; middle, 135° [107, 201]; highest, 150° [93, 208], p = 0.03). Post-stent newly visible perivascular tissue was more frequent in the middle and highest Calcium Index tertiles (lowest, 30.8%; middle, 69.2%; highest, 75.0%, p = 0.049). Minimum stent area was similar after calcium modification by RA irrespective of the severity of the Calcium Index (lowest, 6.7 mm² [5.7, 8.9]; middle, 5.6 mm² [4.9, 6.8]; highest, 6.7 mm² [5.9, 8.2], p = 0.2). Greater calcium modification by RA occurs in severely calcified lesions with smaller lumen diameters to mitigate against stent underexpansion.