Contrast-enhanced excimer laser stepwise approach during PCI for resistant coronary lesions

BACKGROUND

The treatment of resistant coronary lesions (RCL) is a great challenge for interventional cardiologists. The excimer laser coronary atherectomy (ELCA) is a plaque modification tool based on a main mechanism of photomechanical effect leading to mechanical disruption of the plaque. Contrast dye injection during laser delivery has demonstrated to enhance its power.

AIM

To evaluate the effectiveness and safety of the contrast-enhanced ELCA by a stepwise approach in the treatment of RCLs.

METHODS

We retrospectively examined consecutive patients undergoing contrast-enhanced ELCA-assisted PCI between 2018 and 2021 at two Italian sites. RCLs were defined as novo or in-stent undilatable/uncrossable with conventional balloons (SC/NC balloon). The primary endpoint was ELCA technical success defined as the laser catheter crossing the entire length of the target lesion established by angiographic evidence of the catheter tip in the artery distal to the stenosis.

RESULTS

We enrolled 114 patients who underwent contrast-enhanced ELCA-assisted PCI: 58% of the patients had acute coronary syndrome while the left anterior descending artery was the target vessel in 42.1% of cases. The target lesion was most commonly in-stent (56.2%). The 0.9 mm ELCA catheter tip was employed in 89.5% of cases. The most used frequency/fluency profile was 70/70 (39.5%). The use of contrast-enhanced ELCA was associated with high technical, procedural, and clinical success rates (97.4%, 93.7%, and 90.1%, respectively).

CONCLUSIONS

The contrast-enhanced ELCA seems to be a safe and effective treatment option for the management of both de novo and in-stent-resistant coronary lesions.

Calcified coronary lesions: Imaging, prognosis, preparation and treatment state of the art review

Calcific coronary artery stenosis is a complex disease associated with adverse outcomes and suboptimal percutaneous treatment. Calcium plaque modification has emerged as a key strategy to tackle the issues that accompany calcific stenosis - namely reduced device deliverability, unpredictable lesion characteristics, and difficult dilatation. Atherectomy has traditionally been the treatment modality of choice for heavily calcified coronary stenoses. Contemporary technologies have emerged to aid with planning, preparation, and treatment of calcified coronary stenosis in an attempt to improve procedural success and long-term outcomes. In this State Of The Art Review, we synthesize the body of data surrounding the diagnosis, imaging, and treatment of calcific coronary disease, with a focus on i) intravascular imaging, ii) calcific lesion preparation, iii) treatment modalities including atherectomy, and iv) updated treatment algorithms for the management of calcified coronary stenosis.

Effectiveness and Safety of a Novel Intravascular Lithotripsy System for Severe Coronary Calcification: The CALCI-CRACK Trial

BACKGROUND

Intravascular lithotripsy is effective and safe for managing coronary calcification; however, available devices are limited, and complex lesions have been excluded in previous studies. This study aimed to investigate the effectiveness and safety of a novel intravascular lithotripsy system for severe calcification in a population with complex lesions.

METHODS

CALCI-CRACK (treatment of severe calcified coronary lesions with a novel intracoronary shock wave lithotripsy system) (ChiCTR2100052058) was a prospective, single-arm, multicentre study. The primary end point was the procedural success rate. Major safety end points included major adverse cardiovascular events (MACE) and target lesion failure (TLF) at 30 days and 6 months, and severe angiographic complications. Calcification morphology was assessed in the optical coherence tomography (OCT) subgroup.

RESULTS

In total, 242 patients from 15 high-volume Chinese centres were enrolled, including 26.45% of patients with true bifurcation lesions, 3.31% with severely tortuous vessels, and 2.48% with chronic total occlusion, respectively. The procedural success rate was 95.04% (95% confidence interval 91.50%-97.41%), exceeding the prespecified performance goal of 83.4% (P < 0.001). The 30-day and 6-month MACE rates were 4.13% and 4.55%, respectively. TLF rates at those time points were 1.24% and 1.65%, respectively. Severe angiographic complications occurred in 0.42% of patients. In the OCT subgroup (n = 93), 93.55% of calcified lesions were fractured, and minimal lumen area increased from 1.55 ± 0.55 mm2 to 4.91 ± 1.22 mm2 after stent implantation, with acute gain rate of 245 ± 102%.

CONCLUSIONS

The novel intravascular lithotripsy system is effective and safe for managing severely calcified coronary lesions in a cohort that included true bifurcation lesions, severely tortuous vessels, and chronic total occlusion.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR), number ChiCTR2100052058.

Hemodynamics of Saline Flushing in Endoscopic Imaging of Partially Occluded Coronary Arteries

PURPOSE

Intravascular endoscopy can aid in the diagnosis of coronary atherosclerosis by providing direct color images of coronary plaques. The procedure requires a blood-free optical path between the catheter and plaque, and achieving clearance safely remains an engineering challenge. In this study, we investigate the hemodynamics of saline flushing in partially occluded coronary arteries to advance the development of intravascular forward-imaging catheters that do not require balloon occlusion.

METHODS

In-vitro experiments and CFD simulations are used to quantify the influence of plaque size, catheter stand-off distance, saline injection flowrate, and injection orientation on the time required to achieve blood clearance.

RESULTS

Experiments and simulation of saline injection from a dual-lumen catheter demonstrated that flushing times increase both as injection flow rate (Reynolds number) decreases and as the catheter moves distally away from the plaque. CFD simulations demonstrated that successful flushing was achieved regardless of lumen axial orientation in a 95% occluded artery. Flushing time was also found to increase as plaque size decreases for a set injection flowrate, and a lower limit for injection flowrate was found to exist for each plaques size, below which clearance was not achieved. For the three occlusion sizes investigated (90, 95, 97% by area), successful occlusion was achieved in less than 1.2 s. Investigation of the pressure fields developed during injection, highlight that rapid clearance can be achieved while keeping the arterial overpressure to < 1 mmHg.

CONCLUSIONS

A dual lumen saline injection catheter was shown to produce clearance safely and effectively in models of partially occluded coronary arteries. Clearance was achieved across a range of engineering and clinical parameters without the use of a balloon occlusion, providing development guideposts for a fluid injection system in forward-imaging coronary endoscopes.

SCAI Expert Consensus Statement on the Management of Calcified Coronary Lesions

The prevalence of calcification in obstructive coronary artery disease is on the rise. Percutaneous coronary intervention of these calcified lesions is associated with increased short-term and long-term risks. To optimize percutaneous coronary intervention results, there is an expanding array of treatment modalities geared toward calcium modification prior to stent implantation. The Society for Cardiovascular Angiography and Interventions, herein, puts forth an expert consensus document regarding methods to identify types of calcified coronary lesions, a central algorithm to help guide use of the various calcium modification strategies, tips for when using each treatment modality, and a look at future studies and trials for treating this challenging lesion subset.

Intravascular lithotripsy for severe coronary calcification: a systematic review

INTRODUCTION

Coronary artery calcification remains a challenge in percutaneous coronary interventions, due to the higher risk of suboptimal result with subsequent poor clinical outcomes. Intravascular lithotripsy is a novel way of treating severe coronary calcification as it has the ability to modify calcium both circumferentially as well as transmurally, facilitating stent expansion and apposition. We conducted a systematic overview of the published literature on intravascular lithotripsy (IVL) assessing the efficacy and feasibility of IVL in treating severe coronary calcification.

EVIDENCE ACQUISITION

Of the retrieved publications, 62 met our inclusion criteria and were included. A total of 1389 patients (1414 lesions) with significant coronary calcification or under-expanded stents underwent IVL.

EVIDENCE SYNTHESIS

The mean age was 72.03 years (74.7% male). There was a significant improvement in acute and sustained vessel patency, with mean minimal lumen diameter of 2.78±0.46 mm, resulting in acute gain of 1.72±0.51 mm. The acute procedural success rate was 78.2 to 100% with in-hospital complication rate of 5.6 to 7.0%. The majority of the studies reported 30-day MACE, which was between 2.2 to 7.8%.

CONCLUSIONS

The recent studies have highlighted that the use of IVL with adjuvant intracoronary imaging has revolutionized the way of treating heavily calcified, non-dilatable coronary lesions and is likely to succeed the conventional ways of treating these complex lesions. We need further studies to gauge the long-term efficacy and safety of IVL against techniques currently available for calcium modification including conventional balloons, cutting or scoring balloons, rotational atherectomy and laser atherectomy.

Management strategies for heavily calcified coronary stenoses: an EAPCI clinical consensus statement in collaboration with the EURO4C-PCR group

Since the publication of the 2015 EAPCI consensus on rotational atherectomy, the number of percutaneous coronary interventions (PCI) performed in patients with severely calcified coronary artery disease has grown substantially. This has been prompted on one side by the clinical demand for the continuous increase in life expectancy, the sustained expansion of the primary PCI networks worldwide, and the routine performance of revascularization procedures in elderly patients; on the other side, the availability of new and dedicated technologies such as orbital atherectomy and intravascular lithotripsy, as well as the optimization of the rotational atherectomy system, has increased operators' confidence in attempting more challenging PCI. This current EAPCI clinical consensus statement prepared in collaboration with the EURO4C-PCR group describes the comprehensive management of patients with heavily calcified coronary stenoses, starting with how to use non-invasive and invasive imaging to assess calcium burden and inform procedural planning. Objective and practical guidance is provided on the selection of the optimal interventional tool and technique based on the specific calcium morphology and anatomic location. Finally, the specific clinical implications of treating these patients are considered, including the prevention and management of complications and the importance of adequate training and education.

The Role of Intracoronary Imaging for the Management of Calcified Lesions

Interventional cardiologists in everyday practice are often confronted with calcified coronary lesions indicated for percutaneous transluminal coronary angioplasty (PTCA). PTCA of calcified lesions is associated with diverse technical challenges resulting in suboptimal coronary stenting and adverse long-term clinical outcomes. Angiography itself offers limited information regarding coronary calcification, and the adjuvant use of intracoronary imaging such as intravascular ultrasound (IVUS) and Optical Coherence Tomography (OCT) can guide the treatment of calcified coronary lesions, optimizing the different stages of the procedure. This review offers a description of why, when, and how to use intracoronary imaging for PTCA of calcified coronary lesions in order to obtain the most favorable results. We used the PubMed and Google Scholar databases to search for relevant articles. Keywords were calcified coronary lesions, intracoronary imaging, IVUS, OCT, coronary calcium modification techniques, PTCA, and artificial intelligence in intracoronary imaging. A total of 192 articles were identified. Ninety-one were excluded because of repetitive or non-important information.

Treatment of Calcified Lesions Using a Dedicated Super-High Pressure Balloon: Multicenter Optical Coherence Tomography Registry

BACKGROUND

Calcified lesions often lead to difficulty achieving optimal stent expansion. OPN non-compliant (NC) is a twin layer balloon with high rated burst pressure that may modify calcium effectively.

METHODS

Retrospective, multicenter registry in patients undergoing optical coherence tomography (OCT) guided intervention with OPN NC. Superficial calcification with > 180o arc and > 0.5 mm thickness, and/or nodular calcification with > 90o arc were included. OCT was performed in all cases before and after OPN NC, and after intervention. Primary efficacy endpoints were frequency of expansion (EXP) ≥80 % of the mean reference lumen area and mean final EXP by OCT, and secondary endpoints were calcium fractures (CF), and EXP ≥90 %.

RESULTS

50 cases were included; 25 (50 %) superficial, and 25 (50 %) nodular. Calcium score of 4 in 42 (84 %) cases and 3 in 8 (16 %). OPN NC was used alone, or after other devices if further modification was needed, NC in 27 (54 %), cutting in 29 (58 %), scoring in 1 (2 %), IVL in 2 (4 %); or if non-crossable lesion, rotablation in 5 (10 %) cases. EXP ≥80 % was achieved in 40 (80 %) cases with mean final EXP post intervention of 85.7 % ± 8.9. CF were documented in 49 (98 %) cases; multiple in 37 (74 %). There were 1 flow limiting dissection requiring stent deployment and 3 non-cardiovascular related deaths in 6 months follow-up. No records of perforation, no-reflow or other major adverse events.

CONCLUSION

Among patients with heavy calcified lesions undergoing OCT guided intervention with OPN NC, acceptable expansion was achieved in most cases without procedure related complications.

Relationship Between Attenuated Plaque Identified by Intravascular Ultrasound and Thrombus Formation After Excimer Laser Coronary Angioplasty

BACKGROUND

Excimer laser coronary angioplasty (ELCA) has been reported to be a safe and effective atherectomy device in percutaneous coronary intervention (PCI). However, thrombotic complications after ELCA have been occasionally observed. In this study, we evaluated the impact of attenuated plaque on thrombus formation and transient no-reflow after ELCA.

METHODS

This study enrolled 58 lesions in 56 patients who underwent PCI with ELCA. It was a retrospective observational study at a single center. All lesions were imaged by intravascular ultrasound (IVUS) before and immediately after ELCA. On the plaque with ultrasound attenuation, attenuation angle per millimeter and attenuation length were measured. ELCA-induced thrombus was detected by IVUS, and transient no-reflow after ELCA was recorded.

RESULTS

Thrombus was detected in 14 lesions (30 %), and transient no-reflow occurred in 3 lesions (5 %). Lesions with thrombus had a higher mean attenuation angle (median [interquartile range] 142° [112°-152°] vs. 64° [0°-115°]; p = 0.001), maximum attenuation angle (209° [174°-262°] vs. 86° [0°-173°]; p < 0.001), and longer attenuation length (12 mm [8 mm-17 mm] vs. 2 mm [0 mm-5 mm]; p < 0.001). Lesions with thrombus leading to transient no-reflow had a longer lipid length and a significantly higher troponin I level after PCI.

CONCLUSIONS

IVUS-identified attenuated plaque was strongly correlated with ELCA-induced thrombus. Furthermore, attenuation length may predict transient no-reflow.

Angiographic Features and Clinical Outcomes of Balloon Uncrossable Lesions during Chronic Total Occlusion Percutaneous Coronary Intervention

Background: Balloon uncrossable lesions are defined as lesions that cannot be crossed with a balloon after successful guidewire crossing. Methods: We analyzed the association between balloon uncrossable lesions and procedural outcomes of 8671 chronic total occlusions (CTOs) percutaneous coronary interventions (PCIs) performed between 2012 and 2022 at 41 centers. Results: The prevalence of balloon uncrossable lesions was 9.2%. The mean patient age was 64.2 ± 10 years and 80% were men. Patients with balloon uncrossable lesions were older (67.3 ± 9 vs. 63.9 ± 10, p < 0.001) and more likely to have prior coronary artery bypass graft surgery (40% vs. 25%, p < 0.001) and diabetes mellitus (50% vs. 42%, p < 0.001) compared with patients who had balloon crossable lesions. In-stent restenosis (23% vs. 16%. p < 0.001), moderate/severe calcification (68% vs. 40%, p < 0.001), and moderate/severe proximal vessel tortuosity (36% vs. 25%, p < 0.001) were more common in balloon uncrossable lesions. Procedure time (132 (90, 197) vs. 109 (71, 160) min, p < 0.001) was longer and the air kerma radiation dose (2.55 (1.41, 4.23) vs. 1.97 (1.10, 3.40) min, p < 0.001) was higher in balloon uncrossable lesions, while these lesions displayed lower technical (91% vs. 99%, p < 0.001) and procedural (88% vs. 96%, p < 0.001) success rates and higher major adverse cardiac event (MACE) rates (3.14% vs. 1.49%, p < 0.001). Several techniques were required for balloon uncrossable lesions. Conclusion: In a contemporary, multicenter registry, 9.2% of the successfully crossed CTOs were initially balloon uncrossable. Balloon uncrossable lesions exhibited lower technical and procedural success rates and a higher risk of complications compared with balloon crossable lesions.

Contemporary Management of Severely Calcified Coronary Lesions

Coronary artery calcification is increasingly prevalent in our patient population. It significantly limits the procedural success of percutaneous coronary intervention and is associated with a higher risk of adverse cardiovascular events both in the short-term and long-term. There are several modalities for modifying calcified plaque, such as balloon angioplasty (including specialty balloons), coronary atheroablative therapy (rotational, orbital, and laser atherectomy), and intravascular lithotripsy. We discuss each modality’s relative advantages and disadvantages and the data supporting their use. This review also highlights the importance of intravascular imaging to characterize coronary calcification and presents an algorithm to tailor the calcium modification therapy based on specific coronary lesion characteristics.

Calcium Modification in Percutaneous Coronary Interventions

Moderate-severe calcification increases procedural complications and impairs long-term prognosis post-PCI. Intravascular imaging (particularly optical coherence tomography [OCT]) is useful in guiding the treatment of calcified lesions. Weighted sum of calcium length, arc, and thickness on OCT can predict adequate stent expansion, identifying when atherectomy is required. With intravascular imaging guidance, various techniques alone or in combination may be used in an algorithmic fashion to modify calcified lesions. Calcium fracture by balloon angioplasty, cutting/scoring balloons, intravascular lithotripsy (IVL), atherectomy devices, or Excimer laser improves stent expansion. Intravascular imaging is essential in the treatment of in-stent restenosis when luminal and/or abluminal peri-strut calcium is present.

Percutaneous coronary intervention in calcified stenoses: a protocol for a systematic review with meta-analysis, trial sequential analysis and network meta-analysis

INTRODUCTION

Severely calcified coronary stenoses are difficult to treat with percutaneous coronary interventions. The presence of severe calcifications complicates lesion preparation, advancement of stents and achievement of full stent expansion. Intervention in these lesions is associated with an increased risk of complications and procedural failure compared with treatment of less calcified lesions. Due to the high burden of comorbidity, patients with severely calcified lesions are often excluded from interventional trials, and there is little evidence on how to treat these patients.

METHODS AND ANALYSIS

We will conduct a systematic review of randomised trials enrolling patients with calcified coronary artery disease undergoing percutaneous coronary intervention. We will investigate any percutaneous treatment option including any lesion preparation, stenting or postdilatation technique. We will search The Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval System Online, Latin American and Caribbean Health Sciences Literature, Science Citation Index Expanded, and Excerpta Medica database for studies from inception to 31 October 2022. The coprimary outcome is all-cause mortality and serious adverse events. If appropriate, we will conduct meta-analysis, trial sequential analysis and network meta-analysis.

ETHICS AND DISSEMINATION

No ethics approval is required for this study. The results will be published in a peer-reviewed journal in this field.

PROSPERO REGISTRATION NUMBER

CRD42021226034.

Prevalence and outcomes of balloon undilatable chronic total occlusions: Insights from the PROGRESS-CTO

BACKGROUND

The prevalence, treatment, and outcomes of balloon undilatable lesions encountered in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have received limited study.

METHODS

We examined the clinical characteristics and procedural outcomes of balloon undilatable lesions in the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO, NCT02061436).

RESULTS

Of 6535 CTO PCIs performed between 2012 and 2022, 558 (8.5%) lesions were balloon undilatable. In this subset, patients were older (mean age 67 ± 10 vs. 64 ± 10, p < 0.001) and had higher prevalence of comorbidities: diabetes mellitus (54% vs. 40%, p < 0.001), prior PCI (71% vs. 59%, p < 0.001), prior myocardial infarction (52% vs. 45%, p = 0.003), and prior coronary artery bypass graft surgery (44% vs. 25%, p < 0.001). The CTO lesion length was estimated to be 34 ± 23 mm, mean J-CTO score was 2.9 ± 1.1 and mean PROGRESS-CTO score was 1.4 ± 1.0. A cutting balloon was used in 27%, a scoring balloon in 15%, laser in 14%, rotational atherectomy in 28%, orbital atherectomy in 10%, intravascular lithotripsy in 1% and other modalities/approaches in 5%. Balloon undilatable lesions had lower technical success (90.9% vs. 93.8%, p = 0.007) and higher incidence of major adverse cardiovascular events (MACE) (composite of in-hospital death, acute myocardial infarction, stroke, re-PCI, emergency CABG, and pericardiocentesis) (5.0% versus 1.3%, p < 0.001).

CONCLUSION

Approximately 1 in 12 CTO (8.5%) lesions are balloon undilatable. Treatment of balloon undilatable lesions is associated with lower technical success and higher in-hospital MACE.

Plaque modification in calcified chronic total occlusions: the PLACCTON study

INTRODUCTION AND OBJECTIVES

Severe calcification is present in> 50% of coronary chronic total occlusions (CTOs) undergoing percutaneous intervention. We aimed to describe the contemporary use and outcomes of plaque modification devices (PMDs) in this context.

METHODS

Patients were included in the prospective, consecutive Iberian CTO registry (32 centers in Spain and Portugal), from 2015 to 2020. Comparison was performed according to the use of PMDs.

RESULTS

Among 2235 patients, wire crossing was achieved in 1900 patients and PMDs were used in 134 patients (7%), requiring more than 1 PMD in 24 patients (1%). The selected PMDs were rotational atherectomy (35.1%), lithotripsy (5.2%), laser (11.2%), cutting/scoring balloons (27.6%), OPN balloons (2.9%), or a combination of PMDs (18%). PMDs were used in older patients, with greater cardiovascular burden, and higher Syntax and J-CTO scores. This greater complexity was associated with longer procedural time but similar total stent length (52 vs 57mm; P=.105). If the wire crossed, the procedural success rate was 87.2% but increased to 96.3% when PMDs were used (P=.001). Conversely, PMDs were not associated with a higher rate of procedural complications (3.7 vs 3.2%; P=.615). Despite the worse baseline profile, at 2 years of follow-up there were no differences in the survival rate (PMDs: 94.3% vs no-PMDs: 94.3%, respectively; P=.967).

CONCLUSIONS

Following successful wire crossing in CTOs, PMDs were used in 7% of the lesions with an increased success rate. Mid-term outcomes were comparable despite their worse baseline profile, suggesting that broader use of PMDs in this setting might have potential technical and prognostic benefits.

Calcium Modification Therapies in Contemporary Percutaneous Coronary Intervention

Coronary Artery Calcification (CAC) has been known to be associated with worse Percutaneous Coronary Intervention (PCI) short- and long-term outcomes. Nowadays, with the increased prevalence of the risk factors leading to CAC in the population and also more PCI procedures done in older patients and with the growing number of higher-risk cases of Chronic Total Occlusion (CTO) PCI and PCI after Coronary Artery Bypass Grafting (CABG), severe cases of CAC are now encountered on a daily basis in the catheterization lab and remain a big challenge to the interventional community, making it crucial to identify cases of severe CAC and plan a CAC PCI modification strategy upfront. Improved CAC detection with intravascular imaging helped identify more of these severe CAC cases and predict response to therapy and stent expansion based on CAC distribution in the vessel. Multiple available therapies for CAC modification have evolved over the years. Familiarity with the specifics and special considerations and limitations of each of these tools are essential in the choice and application of these therapies when used in severe CAC treatment. In this review, we discuss CAC pathophysiology, modes of detection, and different available therapies for CAC modification.

Case Series and Brief Review Report: Excimer Laser Coronary Atherectomy, Facilitating Daily Complex Interventional Challenges

The excimer laser has revolutionary impact on lesion preparation and chronic total occlusion outcomes. Furthermore, this technology has made huge progression in modern percutaneous intervention, especially in ones labeled as noncrossable lesions. This device has the advantage of crossing lesions that 0.14 wire pass through. The mechanism through which excimer laser coronary atherectomy (ELCA) works are photochemical, photothermal, and photomechanical. In this review cases article, we discuss the uses of ELCA in daily catheterization laboratory alone and with other plaque modification tools. We touch on acute coronary syndrome uses of ELCA, no-balloon crossing lesion, and intervening on deformed stents.

The Impact of Calcium on Chronic Total Occlusion Management

Coronary artery calcification is prevalent in chronic total occlusions (CTO), particularly in those of longer duration and post-coronary artery bypass. The presence of calcium predicts lower procedural success rates and a higher risk of complications of CTO percutaneous coronary intervention. Adjunctive imaging, including pre-procedural computed tomography and intracoronary imaging, are useful to understand the distribution and morphology of the calcium. Specialised guidewires and microcatheters, as well as penetration, subintimal entry and luminal re-entry techniques, are required to cross calcific CTOs. The use of both atherectomy devices and balloon-based calcium modification tools has been reported during CTO percutaneous coronary intervention, although they are limited by concerns regarding safety and efficacy in the subintimal space.

Optimization Study of the Hemodynamics of Saline Flushing in Endoscopic Imaging of Chronic Total Occlusions (CTOs)

PURPOSE

In this study, in vitro experiments and computational fluid dynamic (CFD) simulations are used to expand the understand of the physics of saline flushing of a blocked artery to enable optical imaging. This process involves saline injection, mixing with blood, and advection of the mixture away from the region of interest to provide a clear optical path for imaging.

METHODS

CFD simulations are used as a rapid turn-around tool for the evolutionary design process of an endovascular catheter that combines imaging forward-viewing element with saline flushing lumens.

RESULTS

A novel design and control technique is developed that provides the method to regulate the pressure in a blocked artery during saline flushing, so only small deviations from physiological pressure values are exerted on the damaged artery wall at any time, minimizing risk of rupture. In vitro experiments demonstrate the optical clearing process in phantoms simulating chronic total occlusions (CTOs) in coronary arteries with an opaque blood surrogate being removed by saline flushing. With the CFD compared by the experiments, parametric analyses of artery diameter and curvature, and flushing lumen diameter size were conducted to understand their impact on flushing times and pressures. Different plaque morphologies were studied to explore the feasibility of saline flushing in different CTO conditions.

CONCLUSIONS

A new catheter design is demonstrated to safely and effectively produce saline flushing, leading to a clear optical imaging field, and an improved technique is outlined that overcomes some practical challenges and limitations commonly encountered in angioscopy.

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.

Combined use of rotational and excimer lASER coronary atherectomy (RASER) during complex coronary angioplasty-An analysis of cases (2006-2016) from the British Cardiovascular Intervention Society database

INTRODUCTION

Combining rotational (RA) and excimer laser coronary atherectomy (ELCA)-RASER atherectomy-is technique utilized in the percutaneous management of calcific coronary disease. The evidence base examining its safety and utility is sparse and limited to small case-series. This study examines the patterns and outcomes of RASER atherectomy use in the largest cohort to date.

METHODS

Using the British Cardiac Intervention Society database, data were analyzed on all PCI procedures in the UK between 2006 and 2016. Descriptive statistics and multivariate logistic regressions were used to examine baseline, procedural, and outcome associations with RASER.

RESULTS

We identified 153 (0.02%) RASER atherectomy cases out of 686,358 PCI procedures. Baseline covariates associated with RASER use were age, BMI, diabetes, stable coronary disease, and previous CABG. Procedural co-variates associated with RASER were CTO-PCI, the use of more/longer stents, intravascular imaging, cutting balloons, and microcatheters. Adjusted rates of in-hospital major adverse cardiac/cerebrovascular events (MACCE) were not significantly different with RASER. However, there were higher odds of arterial complications (OR 3.23, 95% CI: 1.58-6.61), slow flow (OR 3.50, 95% CI: 1.29-9.55), and shock induction (OR 9.66, 95% CI: 3.44-27.06).

CONCLUSIONS

RASER atherectomy use in complex PCI is associated with higher risk baseline and procedural characteristics. Although increased rates of shock induction, slow flow, and arterial complications were observed, RASER does not increase the likelihood of in-hospital MACCE, major bleeding, or death.

Laser for balloon uncrossable and undilatable chronic total occlusion interventions

BACKGROUND

There is limited information on use of laser in complex percutaneous coronary interventions (PCI). We examined the impact of laser on the outcomes of balloon uncrossable and balloon undilatable chronic total occlusion (CTO) PCI.

METHODS

We reviewed baseline clinical and angiographic characteristics and procedural outcomes of 4845 CTO PCIs performed between 2012 and 2020 at 32 centers.

RESULTS

Of the 4845 CTO lesions, 752 (15.5%) were balloon uncrossable (523 cases) or balloon undilatable (356 cases) and were included in this analysis. Mean patient age was 66.9 ± 10 years and 83% were men. Laser was used in 20.3% of the lesions. Compared with cases in which laser was not used, laser was more commonly used in longer length occlusions (33 [21, 50] vs. 25 [15, 40] mm, p = 0.0004) and in-stent restenotic lesions (41% vs. 20%, p < 0.0001). Laser use was associated with higher technical (91.5% vs. 83.1%, p = 0.010) and procedural (88.9% vs. 81.6%, p = 0.033) success rates and similar incidence of major adverse cardiac events (3.92% vs. 3.51%, p = 0.805). Laser use was associated with longer procedural (169 [109, 231] vs. 130 [87, 199], p < 0.0001) and fluoroscopy time (64 [40, 94] vs. 50 [31, 81], p = 0.003).

CONCLUSIONS

In a contemporary, multicenter registry balloon uncrossable and balloon undilatable lesions represented 15.5% of all CTO PCIs. Laser was used in approximately one-fifth of these cases and was associated with high technical and procedural success and similar major complication rates.

Efficacy and safety of balloon-assisted microdissection with Sapphire® II 1.0-mm balloon in balloon-uncrossable chronic total occlusion lesions

Objective

Earlier studies have shown that the balloon-assisted microdissection (BAM) technique is feasible using a 1.2- to 1.5-mm small balloon in balloon-uncrossable chronic total occlusion (CTO) lesions. This study was performed to assess the efficacy and safety of the BAM technique with a Sapphire® II 1.0-mm balloon.

Methods

In this retrospective study, patients undergoing percutaneous coronary intervention for CTO were consecutively screened for balloon-uncrossable CTO lesions using BAM with the Sapphire® II 1.0-mm balloon. The patients’ clinical and angiographic characteristics and procedural outcomes were collected for analyses.

Results

Twenty-four balloon-uncrossable CTO lesions were identified. Most of the CTO lesions were located in the right coronary artery, followed by the left anterior descending artery and left circumflex artery. The mean Japanese Multicenter CTO Registry (J-CTO) and Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS CTO) scores were 1.96 and 1.38, respectively. The total technical success rates were 91.6% (22/24) and 75.00% (18/24) for the lesions that were successfully treated with BAM. No patients developed major complications with the exception of one patient who developed a femoral hematoma.

Conclusion

BAM with the Sapphire® II 1.0-mm balloon may be an effective and safe technique for balloon-uncrossable CTO lesions.

Contemporary use of excimer laser in percutaneous coronary intervention with indications, procedural characteristics, complications and outcomes in a university teaching hospital

Background

Excimer laser coronary atherectomy (ELCA) can be used as an adjunctive percutaneous coronary intervention treatment for challenging, heavily calcified lesions. Although previous studies have documented high rates of complication and restenosis, these predate the introduction of the smaller 0.9 mm laser catheter. As the coronary complexity has increased, there has been a renewed interest in the ELCA. This study investigates the indications, procedural characteristics, complications and outcomes of ELCA in a contemporary coronary interventional practice.

Methods

This single-centre study retrospectively analysed 50 patients treated with ELCA between January 2013 and January 2019.

Results

Patients had a mean age of 67.9±11.4 years with a male predominance (65.3%). 25 (50%) cases were performed in patients with stable angina. Failure to deliver the smallest available balloon/microcatheter was the most frequent indication in 32 (64%) cases for ELCA use. 30 (60%) of the procedures were performed via radial access. The 0.9 mm X-80 catheter was used in 41 (82%) of cases, delivering on average 9000±3929 pulses. ELCA-related complications included 2 coronary dissections and 1 perforation, all of which were covered with stents. No major complications could be directly attributed to the use of ELCA. There was one death and one case of stent thrombosis within 30 days of the procedure.

Conclusion

ELCA can be performed safely via the radial approach with a 0.9 mm catheter with a high success rate by suitably trained operators. The low procedure-related complications with contemporary techniques make this a very useful tool for complex coronary interventions, especially for difficult to dilate lesions and chronic total occlusion vessels.

Therapeutic Approach to Calcified Coronary Lesions: Disruptive Technologies

PURPOSE OF REVIEW

Moderate or severe calcification is present in approximately one third of coronary lesions in patients with stable ischemic heart disease and acute coronary syndromes and portends unfavorable procedural results and long-term outcomes. In this review, we provide an overview on the state-of-the-art in evaluation and treatment of calcified coronary lesions.

RECENT FINDINGS

Intravascular imaging (intravascular ultrasound or optical coherence tomography) can guide percutaneous coronary intervention of severely calcified lesions. New technologies such as orbital atherectomy and intravascular lithotripsy have significantly expanded the range of available techniques to effectively modify coronary calcium and facilitate stent expansion. Calcium fracture improves lesion compliance and is essential to optimize stent implantation. Intravascular imaging allows for detailed assessment of patterns and severity of coronary calcium that are integrated into scoring systems to predict stent expansion, identifying which lesions require atherectomy for lesion modification. Guided by intravascular imaging, older technologies such as rotational atherectomy and excimer laser can be incorporated with newer technologies such as orbital atherectomy and intravascular lithotripsy into an algorithmic approach for the safe and effective treatment of patients with heavily calcified coronary lesions.

Breaking the deadlock of calcified coronary artery lesions: A contemporary review

Percutaneous coronary intervention (PCI) of severely calcified lesions is known to result in lower procedural success rates, higher complication rates, and worse long-term clinical outcomes compared to noncalcified lesions. Adequate lesion preparation through calcium modification is crucial in ensuring procedural success and reducing adverse cardiovascular outcomes. There are numerous calcium modification devices currently available whose usefulness depends on the nature of the calcific disease and its anatomical distribution. It can be challenging for the interventionists to decide which device is best suited for their patient. There is also emerging evidence for intravascular imaging in guiding selection of calcium modification devices using parameters such as calcium distribution and depth that directly impact on procedural success and clinical outcomes. In this review we aim to discuss the pathophysiology of coronary calcification, evaluate strategies and technologies of calcium modification and propose an A-M-A-S-A algorithm in managing calcified coronary lesions.

Excimer Laser Atherectomy in Percutaneous Coronary Intervention: A Contemporary Review

Excimer laser coronary atherectomy (ELCA) during percutaneous coronary intervention (PCI) has been in use for more than twenty years. While early experiences were not favorable over balloon angioplasty alone, with improvement in operator technique, patient selection and technology, ELCA has established its own niche in contemporary PCI as a safe and effective atherectomy strategy. With growing experience in complex coronary interventions worldwide, ELCA has become one of the essential atherectomy tools offering unique advantages over other atherectomy devices. In the modern era, ELCA is commonly used for patients with in-stent restenosis, stent under expansion, balloon uncrossable lesions and chronic total occlusions. Technical success rates are reported to be >80% in most situations while procedural complication rates such as vessel dissection and perforation among others are reported to average 9% over the past 25 years with improvement over time. In this review, we provide a comprehensive systematic review of the ELCA system, its practical use, indications, and procedural techniques in the contemporary PCI era.

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.

Treatment of In-Stent Restenosis Using Excimer Laser Coronary Atherectomy and Bioresorbable Vascular Scaffold Guided by Optical Coherence Tomography

The rate of in-stent restenosis (ISR) has become increasingly prevalent with the exponential growth in stent implantation due to an aging population and a higher life expectancy, in addition to the high rates of obesity and diabetes. In this prospective, single operator, all-comer study, we sought to analyze the performance of ELCA followed by bioresorbable vascular scaffold (BVS) placement in patients undergoing percutaneous coronary intervention (PCI) for ISR. A total of 13 patients had ISR treated with a combination of ELCA and BVS, with 9 patients having matched OCT pre, post ELCA and post BVS. Mean age was 65 ± 11.22 and 83% of the patients were male. Hypertension and dyslipidemia were present in 100% of the patients and smoking and diabetes in 50%. After the procedure, we did not detect residual stenosis over 10% in any patient, resulting in a technical success of 100%. No patients had MACE during their hospital stay or within the next six months, resulting in a procedure success of 100%. The mean lumen area increased 0.35 mm² from pre procedure to post ELCA and 3.58 mm² from post ELCA to post BVS. The final difference, from pre procedure to post BVS, was a 3.93 mm² lumen area gain. The mean lumen diameter increased 0.11 mm from baseline to ELCA, 0.95 mm from post laser to BVS implantation and 1.06 mm from pre procedure to post BVS. The NIH area reduced 0.48 mm² from pre to post ELCA, 1.13mm² from post ELCA to BVS implantation and 1.61 mm² from baseline to post BVS implantation. We conclude that ELCA is a safe and feasible debulking method to approach ISR, with high rates of post-procedural BVS success, within six months follow-up.

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.

Clinical outcomes of rotational atherectomy in severely calcified in-stent restenosis: a single-center, retrospective study

Neointimal calcification after stent implantation has been reported as one of the forms of neoatherosclerosis. There are a few patients with in-stent restenosis (ISR) and an undilatable calcified neointima who require rotational atherectomy to achieve sufficient acute gain in lumen diameter. However, the clinical outcomes of rotational atherectomy for undilatable calcified ISR have not been fully elucidated. Therefore, we investigated the safety and efficacy of rotational atherectomy for treating calcified ISR. This retrospective study included 17 patients (20 lesions) who had undergone percutaneous coronary intervention including rotational atherectomy to treat ISR with severely calcified neointima. Kaplan-Meier analysis was used to analyze the data. The mean age of the enrolled patients was 67±18 years, and 71% were men. The patients had highly atherogenic characteristics: 65% had diabetes mellitus and 53% were receiving hemodialysis. Procedural success was obtained in 19 (95%) patients, and the acute gain in lumen diameter was acceptable (1.7±0.6 mm). However, during a median follow-up of 571 days, the incidences of major adverse cardiac and cerebrovascular events per patient and clinical-driven target lesion revascularizations per lesion were relatively high. There were no differences in clinical outcomes according to the baseline characteristics, type of restenotic stents, and therapeutic strategy. In conclusion, clinical outcomes of rotational atherectomy for severely calcified ISR were unfavorable despite a high success rate and acceptable acute gain in lumen diameter.

How Should We Treat Heavily Calcified Coronary Artery Disease in Contemporary Practice? From Atherectomy to Intravascular Lithotripsy

Heavily calcified and densely fibrotic coronary lesions continue to represent a challenge for percutaneous coronary intervention (PCI), as they are difficult to dilate, and it is difficult to deliver and implant drug-eluting stents (DES) properly. Poor stent deployment is associated with high rates of periprocedural complications and suboptimal long-term clinical outcomes. Thanks to the introduction of several adjunctive PCI tools, like cutting and scoring balloons, atherectomy devices, and to the novel intravascular lithotripsy technology, the treatment of such lesions has become increasingly feasible, predictable and safe. A step-wise progression of strategies is described for coronary plaque modification, from well-recognised techniques to techniques that should only be considered when standard manoeuvres have proven unsuccessful. We highlight these techniques in the setting of clinical examples how best to apply them through better patient and lesion selection, with the main objective of optimising DES delivery and implantation, and subsequent improved outcomes.

Chronic Total Occlusion Interventions: Update on Current Tips and Tricks

PURPOSE OF REVIEW

To summarize novel techniques and developments in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

RECENT FINDINGS

Using an algorithmic, step-by-step approach can help overcome several complex CTO lesions subsets, such as proximal cap ambiguity, ostial location, in-stent occlusion, bifurcations, balloon uncrossable and undilatable lesions. Similarly, an algorithmic approach can help prevent and optimally treat CTO PCI-related complication, such as perforation, radiation, and contrast-induced nephropathy. Continual update and reassessment of each operator's algorithm for performing CTO PCI can lead to improved outcomes.

Prevalence, Presentation and Treatment of 'Balloon Undilatable' Chronic Total Occlusions: Insights from a Multicenter US Registry

BACKGROUND

The prevalence, treatment and outcomes of balloon undilatable chronic total occlusions (CTOs) have received limited study.

METHODS

We examined the prevalence, clinical and angiographic characteristics, and procedural outcomes of percutaneous coronary interventions (PCIs) for balloon undilatable CTOs in a contemporary multicenter US registry.

RESULTS

Between 2012 and 2017 data on balloon undilatable lesions were available for 425 consecutive CTO PCIs in 415 patients in whom guidewire crossing was successful: 52 of 425 CTOs were balloon undilatable (12%). Mean patient age was 65 ± 10 years and most patients were men (84%). Patients with balloon undilatable CTOs were more likely to be diabetic (67 vs. 41%, P < 0.001) and have heart failure (44 vs. 28%, P = 0.027). Balloon undilatable CTOs were longer (40 mm [interquartile range, IQR 20-50] vs. 30 [IQR 15-40], P = 0.016), more likely to have moderate/severe calcification (87 vs. 54%, P < 0.001), and had higher J-CTO score (3.2 ± 1.1 vs. 2.5 ± 1.3, P < 0.001) and PROGRESS-CTO complications score (3.9 ± 1.7 vs. 3.1 ± 2.0, P < 0.005). They were associated with lower technical and procedural success (92 vs. 98%, P = 0.024; and 88 vs. 96%, P = 0.034, respectively) and higher risk for in-hospital major adverse events (8 vs. 2%, P = 0.008) due to higher perforation rates. The most frequent treatments for balloon undilatable CTOs were high pressure balloon inflations (64%), rotational atherectomy (31%), laser (21%), and cutting balloons (15%).

CONCLUSIONS

Balloon undilatable CTOs are common and are associated with lower success and higher complication rates.

Utility of adjunctive modalities in Coronary chronic total occlusion intervention

Coronary chronic total occlusion (CTO) intervention remains one of the most challenging domains in interventional cardiology. Due to the technical challenges involved and potential procedural complications, CTO percutaneous coronary intervention (PCI) attempt and success rates remain less than standard PCI. However, the use of several adjunctive tools such as intravascular ultrasound, optical coherence tomography, rotational atherectomy, orbital atherectomy, excimer laser coronary atherectomy and percutaneous left ventricular assist device may contribute to improved CTO PCI success rates or provide better hemodynamic assessment of CTO lesion (i.e., using fractional flow reserve). In this review we present the current literature describing the utility and efficacy of these adjunctive modalities in CTO intervention.