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

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

Difference between antegrade and retrograde orbital atherectomy system debulking using an artificial pulsatile heart model

BACKGROUND

Debulking devices are necessary to treat severe calcified lesions. OAS has a unique characteristic that the burr moves forward and backward. There are few studies reporting the differences of ablation style between only-antegrade and only-retrograde OAS.

AIMS

The aim of this study was to evaluate the difference of ablation style between only-antegrade and only-retrograde orbital atherectomy system (OAS) using an artificial pulsatile heart model (HEARTROID system®) and optical coherence tomography (OCT).

METHODS

The calcified lesion model was inserted into the mid of left anterior descending in the HEARTROID®. Only-antegrade and only-retrograde ablation of OAS were conducted for each five lesions. Pre-OCT, OCT after low speed debulking and OCT after high speed debulking were conducted. The width and the depth of debulked area, the debulked area and the direction of debulked area were investigated.

RESULTS

In all of 210 cross-sections, 91 debulked cross sections were chosen for analysis. Only-antegrade group had 47 debulked cross-sections, and only-retrograde group 44 cross-sections. In the evaluation of OCT after high speed debulking, the debulked area (0.76 mm2 [0.58-0.91] vs. 0.53 mm2 [0.36-0.68], p < 0.001) and the depth of debulked area (0.76 mm [0.58-0.91] vs. 0.53 mm [0.36-0.68], p < 0.001) were significantly higher in only-antegrade group compared to only-retrograde group. The debulked bias and the width of debulked area are not significantly different between the two groups.

CONCLUSIONS

Compared to only-retrograde debulking, only-antegrade debulking acquired larger debulked area because of larger cutting depth, although the debulked bias and the width of debulked area were comparable between the two groups.

Direct Comparison of Rotational vs Orbital Atherectomy for Calcified Lesions Guided by Optical Coherence Tomography

BACKGROUND

There are several retrospective studies comparing rotational atherectomy (RA) and orbital atherectomy (OA), but all percutaneous coronary interventions (PCIs) in those studies were not performed under intracoronary imaging guidance.

OBJECTIVES

This study sought to compare the efficacy and safety of optical coherence tomography (OCT)-guided PCI with RA vs OA.

METHODS

The DIRO (To directly compare RA and OA for calcified lesions, a prospective randomized trial) trial was conducted. We enrolled patients with de novo calcified lesions (arc >180°) assessed by OCT or angiographically moderate or severe calcifications if the OCT catheter could not cross the lesion before any intervention. Eligible patients were randomly 1:1 allocated to lesion preparation with RA vs OA. Stent expansion was defined as the minimum stent area divided by the distal reference area multiplied by 100. Tissue modification was assessed using preatherectomy and postatherectomy OCT images. Procedural outcomes including periprocedural myocardial infarctions were evaluated. Furthermore, clinical events and vascular healing evaluated by OCT at 8 months postprocedure were assessed.

RESULTS

The stent expansion was significantly greater in the RA group vs the OA group (99.5% vs 90.6%; P = 0.02). The maximum atherectomy area was significantly larger in the RA group than in the OA group (1.34 [IQR: 1.02-1.89] mm2 vs 0.83 [IQR: 0.59-1.11] mm2; P = 0.004). The procedural outcomes and clinical events at 8 months did not differ between the groups. The vascular healing was sufficient in both groups.

CONCLUSIONS

The prospective randomized DIRO trial revealed that RA could produce a more favorable tissue modification, which may lead to a larger stent expansion than OA in heavily calcified lesions.

Predictors of coronary artery injury after orbital atherectomy as assessed by optical coherence tomography

PURPOSE

The association between the extent of the wire and device bias as assessed by optical coherence tomography (OCT) in the healthy portion of the vessel and the risk of coronary artery injury after orbital atherectomy (OA) has not been fully elucidated. Thus, purpose of this study is to investigate the association between pre-OA OCT findings and post-OA coronary artery injury by OCT.

METHODS

We enrolled 148 de novo lesions having calcified lesion required OA (max Ca angle > 90°) in 135 patients who underwent both pre- and post-OA OCT. In pre-OA OCT, OCT catheter contact angle and the presence or absences of guide-wire (GW) contact with the normal vessel intima were assessed. Also, in post-OA OCT, we assessed there was post-OA coronary artery injury (OA injury), defined as disappearance of both of intima and medial wall of normal vessel, or not.

RESULTS

OA injury was found in 19 lesions (13%). Pre-PCI OCT catheter contact angle with the normal coronary artery was significantly larger (median 137°; inter quartile range [IQR] 113-169 vs. median 0°; IQR 0-0, P < 0.001) and more GW contact with the normal vessel was found (63% vs. 8%, P < 0.001). Pre-PCI OCT catheter contact angle > 92° and GW contact with the normal vessel intima were associated with post-OA vascular injury (Both: 92% (11/12), Either: 32% (8/25), Neither: 0% (0/111), P < 0.001).

CONCLUSION

Pre-PCI OCT findings, such as catheter contact angle > 92° and guide-wire contact to the normal coronary artery, were associated with post-OA coronary artery injury.

Outcomes of Orbital Atherectomy for the Treatment of Severely Calcified Coronary Artery Lesions

Background Orbital atherectomy (OA) is used to prepare severely calcified coronary artery lesions before percutaneous coronary intervention (PCI). Intravascular ultrasound (IVUS) is used to determine the plaque volume and degree of stenosis within the arterial vessel. This study evaluated the safety and efficacy of OA for treating severely calcified coronary lesions and determined if IVUS impacted these outcomes. Methods We retrospectively collected data from a single center of patients with severe coronary artery calcification who underwent OA. The data on baseline characteristics and procedural and clinical outcomes were collected and analyzed. Results A total of 374 patients underwent OA. The mean age was 69 ± 12.7; 53.6% were Black, and 38% were female. Hypertension was present in 96% of the patients, followed by hyperlipidemia in 79.4%, diabetes mellitus in 53.7%, and chronic kidney disease (CKD) in 22.7%. More patients had presented with a non-ST-elevation myocardial infarction (NSTEMI) compared to ST-elevation myocardial infarction (STEMI) at 36.3% versus 4.3%, respectively. The radial artery was used in 35.4% of the cases, and the left anterior descending artery (LAD) was the most commonly treated vessel with OA at 61%, followed by the right coronary artery (RCA) at 30.7%. IVUS was utilized in 63.4% of cases. The most common complication of the procedure was perforation and dissection at an equal proportion of 1.3% among all patients. The no-reflow rate was 0.5%, and 0.5% developed post-procedural myocardial infarction (MI). The average length of stay was 4.7 days, while a marginal proportion, at 10.5%, had same-day discharge with no recorded complications. Conclusion In this analysis of patients with severely calcified coronary lesions, OA had low rates of major adverse cardiovascular events (MACE) and was considered a safe and effective treatment for complex coronary lesions.

Impact of calcified nodule on target lesion failure after stent implantation in hemodialysis patients

BACKGROUND

Little is known about intravascular imaging predictors of cardiac events after drug-eluting stent (DES) implantation in hemodialysis (HD) patients. We aimed to reveal the association between calcified nodules (CN) and target lesion failure (TLF) in HD patients after DES implantation.

METHODS

We enrolled 114 HD patients who underwent DES implantation between October 2016 and October 2020. The patients were divided into a CN group (39%, 44 patients) and a non-CN group (61%, 70 patients). The primary endpoint was the incidence of TLF, including cardiac death, target vessel myocardial infarction, and clinically driven target lesion revascularization.

RESULTS

HD duration was longer, and the calcium burden was higher in the CN group than in the non-CN group. Over a median follow-up of 607 days [interquartile range: 349-965 days], the cumulative incidence curve showed that the CN group had a significantly higher incidence of TLF than the non-CN group (31.8% vs. 11.4% within 3 years, p = 0.008).　On Fine-Gray sub-distribution hazard model analysis, the CN group was associated with an increased rate of TLF (hazard ratio [HR]: 2.86; 95% confidence interval [CI]: 1.21-6.75, p = 0.016). An in-stent CN was observed in 73% of the lesions with target lesion revascularization in the CN group, whereas no in-stent CN was observed in the non-CN group (p = 0.026).

CONCLUSIONS

CN was an independent predictor of TLF in patients undergoing HD. In-stent CN was an important cause of TLF after DES implantation in CN lesions in HD patients; therefore, a different strategy should be considered for treating the lesions.

Mid-term outcome of de novo lesions vs. in stent restenosis treated by intravascular lithotripsy procedures: Insights from the French Shock Initiative

BACKGROUND

Intravascular lithotripsy (IVL) is a promising new technology for disrupting de-novo calcified coronary lesions (DNL) before percutaneous coronary intervention (PCI). We assessed 12-month outcomes of IVL in patients undergoing PCI for DNL or intra stent restenosis (ISR) lesions related to device underexpansion.

METHODS

Prospective analysis of patients in the multicentre all-comers French Shock Initiative IVL registry. The primary safety endpoints in this analysis were in-hospital and 12-month major adverse cardiovascular events (MACE: cardiac death, myocardial infarction or target vessel revascularization). The primary effectiveness endpoint was procedural success, defined as <30% residual stenosis without severe angiographic complications. Event rates were analysed for the cohort and for DNL and ISR procedures separately.

RESULTS

A total of 220 lesions were treated (76.7% DNL and 23.3% ISR) in 202 patients. Procedural success was achieved in 95.5% of patients (DNL group: 96.5%; ISR group: 92.0%). In-hospital MACE occurred in 6.4% of cases, mainly driven by periprocedural infarctions. The rate of MACE-free survival at 1 year was 86.6% in the overall cohort. Rates of target vessel (TVR) and lesion (TLR) revascularisation were 6.4% and 2.5%, respectively. The 1-year MACE rate was 91.5% in DNL group and 83.8% in ISR group.

CONCLUSIONS

In this large all-comers IVL cohort, rates of in-hospital and 1-year MACE were moderate. The safety and efficiency of IVL was comparable in DNL and ISR lesions. A comparative study of the impact of IVL on outcomes appears warranted.

Outcomes of rotational atherectomy versus orbital atherectomy for the treatment of heavily calcified coronary stenosis: A systematic review and meta-analysis

INTRODUCTION

The optimal approach to deal with severe coronary artery calcification (CAC) during percutaneous coronary intervention (PCI) remains ill-defined.

METHODS

We conducted an electronic database search of all published studies comparing Orbital versus Rotational Atherectomy in patients undergoing PCI.

RESULTS

Eight observational studies were included in the analysis. Overall, there were no significant differences in Major-adverse-cardiac-events/MACE (OR: 0.81, CI: 0.63-1.05, p = .11), myocardial-infarction/MI (OR: 0.75, CI: 0.56-1.00, p = .05), all-cause mortality (OR: 0.82, CI: 0.25-2.64, p = .73) or Target-vessel-revascularization/TVR (OR: 0.72, CI: 0.38-1.36, p = .31). However, OA was associated with lower long-term MACE (1-year), (OR: 0.66, CI: 0.44-0.99, p = .04), long-term TVR (OR: 0.40, CI: 0.18-0.89, p = .03), and short-term MI (in-hospital and 30-day) (OR: 0.64, CI: 0.44-0.94, p = .02). OA was associated with more coronary artery dissections (OR: 2.61, CI: 1.38-4.92, p = .003) and device-related coronary perforations (OR: 2.79, CI: 1.08-7.19, p = .03). There were no differences in cardiac tamponade (OR: 1.78, CI: 0.37-8.69, p = .47). OA was noted to have significantly lower fluoroscopy time (MD: -3.96 min, CI: -7.67, -0.25; p = .04) compared to RA. No significant difference was noted in terms of contrast volume between the two groups (OR: -4.35 ml, CI: -14.52, 23.22; p = .65).

CONCLUSION

Although there was no difference in overall MACE, MI, all-cause mortality and TVR, OA was associated with lower long-term MACE and short-term MI. OA is associated with lower fluoroscopy time but higher rates of coronary artery dissection and coronary perforation.

Contemporary technologies to modify calcified plaque in coronary artery disease

With aging society, one of the more challenging obstacles in percutaneous coronary interventions are calcified coronary lesions. Calcified lesions may impede stent delivery, limit balloon and stent expansion, cause uneven drug distribution, and hinder wire advancement. Even in the setting of acceptable procedural success, vessel calcification is independently associated with increased target lesion revascularization rates at follow-up and lower survival rates. In order to effectively manage such lesions, dedicated technologies have been developed. Atherectomy aims at excising tissue and debulking plaques, as well as compressing and reshaping the atheroma, generally referred to as lesion preparation that enables further balloon and/or stent expansion in contemporary clinical practice. In the current review, we will discuss the available methods for atherectomy, including rotational, orbital, and excimer laser coronary atherectomy, as well as intravascular lithotripsy. In addition, we will review the role of imaging in calcified lesions.

Management of calcified coronary artery bifurcation lesions

Calcified coronary artery bifurcation lesions (CBL) remain a challenge for the interventional cardiologist. Evidence regarding treatment of CBL is minimal. Optimal plaque modification is the most important step prior to stent deployment. Provisional stenting is the preferred strategy for most bifurcation lesions. However, two-stent strategy should be considered for BL with compromised large SB (>2.5 mm) supplying a large territory, >70% SB stenosis and lesions more than 5 mm long. In this contemporary review article, we present a simplified approach to treating CBL and demonstrate the approach to specific case examples using our newly developed mobile application, BifurcAID.

Short term outcomes of rotational atherectomy versus orbital atherectomy in patients undergoing complex percutaneous coronary intervention: a systematic review and meta-analysis

OBJECTIVE

Coronary artery calcification (CAC) is one of the paramount hurdles for percutaneous coronary intervention (PCI) since it impedes stent delivery and complete expansion. This study intended to evaluate the short-term clinical and procedural outcomes comparing rotational atherectomy (RA) and orbital atherectomy (OA) in patients with heavily calcified coronary lesions undergoing PCI. Design: This systematic review and meta-analysis included all head-to-head published comparisons of coronary RA versus OA. Procedural endpoints and post-procedural clinical outcomes (30 days/in-hospital), were compared. RevMan 5.3 software was used for data analysis. Results: Seven retrospective observational investigations with a total of 4623 patients, including 3203 patients in the RA group and 1420 patients in the OA group, were incorporated. Compared with OA, the RA group was associated with a higher incidence of myocardial infarction at short-term follow-up (OR: 1.56, 95% CI: 1.07-2.29, p = .02, I² = 0%). No difference was noted among other short-term post-procedural clinical outcomes including all-cause mortality, target vessel revascularization, or major adverse cardiac events. Among procedural complications, RA was associated with reduced coronary artery dissection and arterial perforation. Increased fluoroscopy time was observed in the RA cohort as compared with OA (MD: 4.78, 95% CI: 2.25-7.30, p = .0002, I² = 80%). Conclusion: RA was associated with fewer vascular complications, but at a cost of higher incidence of myocardial infarction and higher fluoroscopy time compared with OA, at short term follow-up. OA is a safe and effective alternative for the management of CAC.

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.

Intravascular Imaging to Guide Lithotripsy in Concentric and Eccentric Calcific Coronary Lesions

BACKGROUND

Calcified coronary lesions still represent a challenge for coronary angioplasty, with sub-optimal acute PCI results causing more frequent late stent failure.

PURPOSE

The study aimed at the evaluation of the immediate procedural outcome in a real-world consecutive population of a selective use of lithotripsy based on the intravascular imaging assessment with IVUS or OCT.

METHODS AND RESULTS

Thirty-one calcified stenoses (28 patients) out of a total of 455 lesions (370 patients) treated between November 2018 and May 2019 received IVL under intravascular imaging guidance. The majority of the IVL lesions had angiographically severe calcifications and were selected after intravascular imaging. A smaller group was identified by poor expansion after high-pressure balloon dilatation, in one case despite preliminary small burr Rotablation. After IVL, when OCT was performed calcium fractures were observed in 71% of cases. After OCT/IVUS guided stent optimization a satisfactory lumen enlargement (minimal stent area 7.09 ± 2.77 mm²) was observed with good stent expansion (residual area stenosis<20% in 29 lesions, 93.5%) Peri-procedural complications were limited to one dissection at the distal edge requiring an additional stent and 3 peri-procedural myocardial infarctions. There were no periprocedural coronary perforations or pericardial effusions, and no in-hospital or 30 days stent thrombosis. When patients were divided into two subgroups according to a calcium arc ≤180° (Group A: 10 lesions, calcium arc 140 ± 24°; Group B: 21 lesions, calcium arc 289 ± 53°), at OCT Group B presented also a higher number of calcium fractures post IVL than group A (group A: 38% vs group B: 92%, p = 0.03). The in-stent minimum lumen diameter (MSD), the in stent minimal lumen area (MSA) and the acute gain, however, were similar between the two groups (acute gain group A: 1.22 ± 0.29 mm; group B: 1.31 ± 0.52 mm, p = 0.63).

CONCLUSIONS

A standardized algorithm applying intravascular imaging guidance of IVL facilitated second generation DES expansion delivers excellent immediate lumen expansion and patient outcome, both in concentric and eccentric calcifications.

Rotational Atherectomy: A Contemporary Appraisal

Rotational atherectomy (RA) is an atheroablative technology that enables percutaneous coronary intervention for complex, calcified coronary lesions. RA works on the principle of 'differential cutting' and preferentially ablates hard, inelastic, calcified plaque. The objective of RA use has evolved from plaque debulking to plaque modification to enable balloon angioplasty and optimal stent expansion. The clinical experience over the past 30 years has informed the current best practices for RA with use of smaller burr sizes, short ablation runs a 'pecking' motion, and avoidance of sudden decelerations. This has led to significant improvements in procedural safety and a reduced rate of associated complications. This article reviews the principles, clinical indications, contemporary evidence, technical considerations and complications associated with the use of RA.

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.

Contemporary Approach to Heavily Calcified Coronary Lesions

Percutaneous treatment of heavily calcified coronary lesions still represents a challenge for interventional cardiology, with higher risk of immediate complications, late failure due to stent underexpansion and malapposition, and consequently poor clinical outcome. Good characterisation of calcium distribution with multimodal imaging is important to improve the successful treatment of these lesions. The use of traditional or new dedicated devices for the treatment of calcified lesions allows better lesion preparation; therefore, it is important that we know the different mechanisms and technical features of these devices.