Therapeutic Approach to Calcified Coronary Lesions: Disruptive Technologies

Challenges and Advances in Interventional Cardiology for Coronary Artery Disease Management

The development of percutaneous coronary intervention (PCI) has been one of the greatest advances in cardiology and has changed clinical practice for patients with coronary artery disease (CAD). Despite continuous improvements in operators' experience, techniques, and the development of new-generation devices, significant challenges remain in improving the efficacy of PCI, including calcification, bifurcation, multivascular disease, stent restenosis, and stent thrombosis, among others. The present review aims to provide an overview of the current status of knowledge of endovascular revascularization in CAD, including relevant trials, therapeutic strategies, and new technologies addressing particular scenarios that can impact the prognosis of this vulnerable population.

Review of intravascular lithotripsy for treating coronary, peripheral artery, and valve calcifications

Management of intracoronary calcium (ICC) continues to be a challenge for interventional cardiologists. There have been significant advances in calcium treatment devices. However, there still exists a knowledge gap regarding which devices to choose for the treatment of ICC. The purpose of this manuscript is to review the principles of intravascular lithotripsy (IVL) and clinical data. The technique of IVL will then be compared to alternative calcium treatment devices. Clinical data will be reviewed concerning the treatment of coronary, peripheral artery and valvular calcifications. Controversies to be discussed include how to incorporate IVL into your practice, what is the best approach for treating calcium subtypes, how to approach under-expanded stents, what is the ideal technique for performing IVL, how safe is IVL, whether imaging adds value when performing IVL, and how IVL fits into a treatment program for peripheral arteries and calcified valves.

Intravascular Lithotripsy for Calcified Left Main Artery Disease

Left main coronary artery disease subtends a large area of potentially jeopardized myocardium. Percutaneous coronary intervention for severe left main coronary artery disease is a reasonable treatment option for select patients. Severe coronary artery calcium of the left main artery increases the complexity of percutaneous coronary intervention and is associated with increased risk of periprocedural complications and worse long-term clinical outcomes. Intravascular lithotripsy (IVL) utilizes sonic pressure waves to modify severe coronary artery calcium and has emerged as a safe and effective alternative to coronary atherectomy. However, left main lesions were excluded from regulatory approval clinical trials of IVL. Herein, we review all available data regarding the use of IVL treatment for severe left main coronary artery disease.

Impact of Calcium Eccentricity on the Safety and Effectiveness of Coronary Intravascular Lithotripsy: Pooled Analysis From the Disrupt CAD Studies

BACKGROUND

Coronary intravascular lithotripsy (IVL) safely facilitates successful stent implantation in severely calcified lesions. This analysis sought to determine the relative impact of lesion calcium eccentricity on the safety and effectiveness of IVL using high-resolution optical coherence tomography imaging.

METHODS

Individual patient-level data (n=262) were pooled from 4 distinct international prospective studies (Disrupt CAD I, II, III, and IV) and analyzed by an independent optical coherence tomography core laboratory. IVL performance in eccentric versus concentric calcification was analyzed by dividing calcified lesions into quartiles (≤180° [most eccentric], 181°-270°, 271°-359°, and 360° [concentric]) by maximum continuous calcium arc.

RESULTS

In the 230 patients with clear imaging field on optical coherence tomography, there were no differences in preprocedure minimum lumen area, diameter stenosis, or maximum calcium thickness. The calcium length and volume index increased progressively with increasing mean and maximum continuous calcium arc (ie, concentricity). Conversely, the minimum calcium thickness decreased progressively with increasing concentricity. Post-procedure, the number of calcium fractures, fracture depth, and fracture width increased with increasing concentricity, with a 4-fold increase in the number of fractures in lesions with 360° of calcium arc compared with ≤180°. This increase in IVL-induced calcium fracture with increasing calcium burden and concentricity facilitated stent expansion and luminal gain such that there were no significant differences across quartiles.

CONCLUSIONS

IVL induced calcium fractures proportional to the magnitude of coronary artery calcium, including in eccentric calcium, leading to consistent improvements in stent expansion and luminal gain in both eccentric and concentric calcified coronary lesions.

Safety and Efficacy of Orbital Atherectomy in the All-Comer Population: Mid-Term Results of the Lower Silesian Orbital Atherectomy Registry (LOAR)

BACKGROUND

Coronary calcifications represent a challenging subset for the interventional cardiologist performing percutaneous coronary intervention (PCI) and are well-established risk factors for adverse outcomes. Adequate plaque modification prior to stent implantation is critical to achieve an optimal outcome following PCI. Recently, a novel orbital atherectomy device has been introduced into clinical practice to modify calcified plaques. We evaluated the mid-term safety and efficacy of OA in a high-risk "all-comers" population.

METHODS

We evaluated 96 consecutive patients with severely calcified coronary lesions who underwent PCI facilitated by the orbital atherectomy device.

RESULTS

In-hospital MACCE was 5.2% without target lesion revascularization. At 6-month follow-up, the MACCE rate was 10.4% with a concomitant TLR rate of 1%.

CONCLUSIONS

Our mid-term data showed good safety and efficacy of orbital atherectomy as a plaque-modifying tool in an all-comers cohort with severely calcified coronary lesions.

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.

Intravascular Ultrasound Guided Intervention in Calcified Coronary Lesions Showed Good Clinical Outcomes during One Year Follow-Up

BACKGROUND

Calcified coronary lesions can cause stent under-expansion, malapposition, and polymer degradation, hence increasing the risk of adverse clinical outcomes. Percutaneous coronary intervention (PCI) guided by intravascular ultrasound (IVUS) has been used regularly to improve outcomes. Our primary aim was to evaluate the clinical efficacy of IVUS-guided PCI in calcified coronary lesions.

METHODS

From August 2018 to December 2021, we prospectively included 300 patients in the CAPIRO study (CAlcified plaque in patients receiving Resolute Onyx®) at three educational hospitals in Jeonbuk Province. We studied 243 patients (265 lesions) who were followed up for over a year. Based on coronary calcification by IVUS analysis, the patient population was categorized into two groups (Group I: non/mild calcification; Group II: moderate/severe calcification (maximum calcium arc >180° and calcium length > 5 mm)). One-to-one Propensity Score Matching was used to match the baseline characteristics. The stent expansion rate was analyzed by recent criteria. The primary clinical outcome was Major Adverse Cardiac Events (MACE), which included Cardiac death, Myocardial Infarction (MI), and Target Lesion Revascularization (TLR).

RESULTS

After follow-up time, the MACE rate in Group I was 1.99%, comparable to Group II's 1.09% (p = 0.594). The components of MACE did not significantly differ between the two groups. Based on absolute MSA or MSA/MVA at MSA site criteria, the stent expansion rate in Group II was lower than that of Group I. Nevertheless, based on recent relative criteria, the stent expansion rate in both groups was comparable.

CONCLUSIONS

After more than a year of follow-up, IVUS-guided PCI in moderate/severe calcification lesions was associated with good clinical outcomes, which was comparable with non/mild calcification lesions. Future studies with a larger sample size and a more extended follow-up period are required to clarify our findings.

Comparison of Orbital Atherectomy and Rotational Atherectomy in Calcified Left Main Disease: Short-Term Outcomes

BACKGROUND

Coronary calcifications, particularly in left main disease (LMD), are independently associated with adverse outcomes of percutaneous coronary intervention (PCI). Adequate lesion preparation is pivotal to achieve favorable short- and long-term outcomes. Rotational atherectomy devices have been used in contemporary practice to obtain adequate preparation of the calcified lesions. Recently, novel orbital atherectomy (OA) devices have been introduced to clinical practice to facilitate the preparation of the lesion. The objective of this study is to compare the short-term safety and efficacy of orbital and rotational atherectomy for LMD.

METHODS

we retrospectively evaluated a total of 55 consecutive patients who underwent the LM PCI supported by either OA or RA.

RESULTS

The OA group consisted of 25 patients with a median SYNTAX Score of 28 (26-36). The Rota group consisted of 30 patients with a median SYNTAX Score of 28 (26-33.1) There were no statistical differences in MACCE between the RA and OA subpopulations when recorded in-hospital (6.7% vs. 10.3% p = 0.619) as well as in a 1-month follow-up after the procedure (12% vs. 16.6% p = 0.261).

CONCLUSION

OA and RA seem to be similarly safe and effective strategies for preparating the lesion in the high-risk population with calcified LMD.

Can Most Calcified Coronary Stenosis Be Optimized With Coronary Intravascular Lithotripsy?

Intravascular lithotripsy can be used as an effective therapy for lesion preparation in severely calcified lesions. The mechanism, as shown by optical coherence tomography, is calcium fractures. The aforementioned modification is performed with minimal risk of perforation, no-reflow and a low incidence of flow-limiting dissection and myocardial infarctions. Other techniques, such as cutting or scoring balloons and rotational atherectomy have also been shown to increase luminal diameter, but other complications, such as distal embolization, induced by these treatment modalities, are a source of concern. This review describes a single-center study of all-comer patients, including those with complex characteristics. This therapy is very effective, with a very low risk of complications. In this article, we characterize the mechanism of action of the intravascular lithotripsy catheter, its optical coherence tomography validation, clinical applications, and comparison with other calcium-modifying technologies, as well as future directions, which can be used to improve the technology.

Pulsatile intravascular lithotripsy: A novel mechanism for peripheral artery calcium fragmentation and luminal expansion

OBJECTIVE

To assess the feasibility and treatment effect of pulsatile intravascular lithotripsy (PIVL) on calcified lesions in a cadaveric model of peripheral artery disease.

BACKGROUND

PIVL represents a novel potential approach to intravascular lithotripsy for the treatment of vascular calcification.

METHODS

In this preclinical device-feasibility study, technical success, calcium morphology and luminal expansion before and after PIVL treatment were evaluated in surgically isolated, perfused atherosclerotic lower-leg arteries and in perfused whole cadaveric lower legs. Analytical methods included micro-computed tomography (μCT), intravascular optical coherence tomography, digital subtraction angiography, and quantitative coronary analysis.

RESULTS

Treatment delivery was successful in all whole-leg specimens (N = 6; mean age 74.2, 66 % female) and in the 8 excised vessels with diameter appropriate to the PIVL balloon (2 vessels exceeding diameter specifications were excluded). There were no vessel perforations. After PIVL, excised vessels showed extensive evidence of new, full-thickness fractures in lesions with calcium arc exceeding 152° and with calcium wall thickness between 0.24 mm and 1.42 mm. PIVL fractures were observed in intimal nodules, sheets, shingles, and medial plates. Vessels within whole-leg specimens also showed full-thickness fracturing and a mean of 1.9 ± 0.9 mm in acute luminal gain, 101.6 ± 99.5 % gain in total minimum cross-sectional area, and a 31.7 ± 13.4 % relative reduction in stenosis (P < 0.001 for all analyses).

CONCLUSIONS

In a cadaveric model, PIVL treatment was technically feasible, fractured both circumferential and eccentric calcium lesions, and resulted in acute luminal gain. A clinical feasibility study of PIVL is currently enrolling.

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.

Intravascular optical coherence elastography

Optical coherence elastography (OCE), a functional extension of optical coherence tomography (OCT), visualizes tissue strain to deduce the tissue's biomechanical properties. In this study, we demonstrate intravascular OCE using a 1.1 mm motorized catheter and a 1.6 MHz Fourier domain mode-locked OCT system. We induced an intraluminal pressure change by varying the infusion rate from the proximal end of the catheter. We analysed the pixel-matched phase change between two different frames to yield the radial strain. Imaging experiments were carried out in a phantom and in human coronary arteries in vitro. At an imaging speed of 3019 frames/s, we were able to capture the dynamic strain. Stiff inclusions in the phantom and calcification in atherosclerotic plaques are associated with low strain values and can be distinguished from the surrounding soft material, which exhibits elevated strain. For the first time, circumferential intravascular OCE images are provided side by side with conventional OCT images, simultaneously mapping both the tissue structure and stiffness.

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.

Calcific Plaque Modification by Acoustic Shockwaves: Intravascular Lithotripsy in Cardiovascular Interventions

PURPOSE OF REVIEW

To provide a review of recent literature on the treatment of moderate-to-severe calcification in coronary and peripheral vasculature with intravascular lithotripsy (Shockwave Medical, Santa Clara, CA).

RECENT FINDINGS

Moderate-to-severe calcific plaques constitute a significant proportion of lesions treated with transcatheter interventions in the coronary and peripheral vascular beds and portend lower procedural success rates, increased periprocedural major adverse events, and unfavorable long-term clinical outcomes compared to non-calcific plaques. Intravascular lithotripsy (IVL) is a new technique that uses acoustic shock waves in a balloon-based system to induce fracture in the calcium deposits to facilitate luminal gain and stent expansion. IVL demonstrated high procedural success and low complication rates in the management of moderate-to-severe calcification in coronary and peripheral vascular beds and led to large luminal gain by modification of calcific plaque as assessed by optical coherence tomography. Further studies will determine the role of IVL in an integrated, protocolized approach to the treatment of severely calcified plaques in the coronary and peripheral vascular beds.

Use of Coronary Intravascular Lithotripsy: A Comprehensive Review of Literature

Severe coronary artery calcification (CAC) is associated with high rate of procedural complications. The current techniques that facilitate PCI in moderate to severe CAC have significant risk of complications, including periprocedural myocardial infarction (MI), dissection, perforation and transient atrioventricular block. Coronary Intravascular lithotripsy (IVL) is a novel technology for the treatment of moderate to severe calcified lesions. IVL uses sonic pressure waves to break down the calcium deposits with no to minimal impact on the blood vessel tissues, which makes IVL a safe option with high procedural success and minimal complications. Here, we discuss coronary IVL as a treatment option for CAC and summarize the major clinical trials performed evaluating the safety and outcome of IVL.

Synergies between therapeutic ultrasound, gene therapy and immunotherapy in cancer treatment

Due to the ease of use and excellent safety profile, ultrasound is a promising technique for both diagnosis and site-specific therapy. Ultrasound-based techniques have been developed to enhance the pharmacokinetics and efficacy of therapeutic agents in cancer treatment. In particular, transfection with exogenous nucleic acids has the potential to stimulate an immune response in the tumor microenvironment. Ultrasound-mediated gene transfection is a growing field, and recent work has incorporated this technique into cancer immunotherapy. Compared with other gene transfection methods, ultrasound-mediated gene transfection has a unique opportunity to augment the intracellular uptake of nucleic acids while safely and stably modulating the expression of immunostimulatory cytokines. The development and commercialization of therapeutic ultrasound systems further enhance the potential translation. In this Review, we introduce the underlying mechanisms and ongoing preclinical studies of ultrasound-based techniques in gene transfection for cancer immunotherapy. Furthermore, we expand on aspects of therapeutic ultrasound that impact gene therapy and immunotherapy, including tumor debulking, enhancing cytokines and chemokines and altering nanoparticle pharmacokinetics as these effects of ultrasound cannot be fully dissected from targeted gene therapy. We finally explore the outlook for this rapidly developing field.