Assessment of optimum stent deployment by stent boost imaging: comparison with intravascular ultrasound

Value of stent boost imaging in decision making after coronary stenting

BACKGROUND

Several studies reported the comparability of digital stent enhancement techniques (including stent boost imaging) in detecting suboptimal results of coronary stenting with Intra Vascular Ultrasound and optical coherence tomography.

AIMS

to assess results of stent deployment and determine the incidence of suboptimal results requiring changing final decision using stent boost imaging.

METHODS

This cross-sectional study included 120 patients eligible for PCI were recruited during a period of one year (January 2021 to 2022) using DES.

RESULTS

Suboptimal results were found in 38% of the PCI cases with stents (angiography guided). Importantly it was found that improper lesion preparation in our practice could not help improving stent optimization. Also, angiography guided PCI has significant incidence of suboptimal results. Digital stent enhancement techniques like stent boost have significant and important value in better decision making. After adjusting for age and sex, six factors were identified as independent predictors for final decision change (stent length, LAD/RCA affection, proximal segment affection, calcification, and optical coherence tomography.

CONCLUSION

This study has confirmed the utility of stent boost for the optimization of PCI in daily practice. Stent Boost is a simple and costless technique that provides an accurate assessment of a deployed stent without extending the procedure time and without more risk. It appears to be useful for the immediate evaluation of stent expansion and optimization of PCI by additional post-dilatation, when appropriate. Future studies are needed to determine whether Stent Boost data will correlate with adverse long-term clinical outcomes in patients undergoing PCI.

Clinical Characteristics and Outcomes following Percutaneous Coronary Intervention in Unprotected Left Main Disease: A Single-Center Study

Background: Hemodynamically significant unprotected left main (LM) coronary artery disease is a high-risk clinical condition because of the large area of myocardium at risk, and it requires prompt revascularization. Percutaneous coronary intervention (PCI) is an appropriate alternative to coronary artery bypass grafting (CABG) for revascularization of unprotected LM disease in patients with low-to-intermediate anatomic complexity or when the patient refuses CABG after adequate counseling by the heart team. Methods: We retrospectively evaluated 201 patients receiving left main (LM) provisional one-stent or two-stent procedures, and we assessed the clinical characteristics and outcomes of patients undergoing unprotected LM PCI. Results: The mean age was 66.5 ± 9.9 years, and 72% were male. The majority of the subjects presented several cardiovascular risk factors, among which arterial hypertension (179 patients, 89.5%) and dyslipidemia (173 patients, 86.5%) were the most frequent. Out of all patients, 162 (81.8%) underwent revascularization by using the one-stent technique, while the two-stent technique was used in 36 patients (18.2%). The median value of fractional flow reserve (FFR) of the side branch was 0.9 [0.85–0.95], and 135 patients (67.1%) showed a value of FFR > 0.8. One hundred nine patients (54.2%) had a stent enhancement side branch length (SESBL) > 2, with median values of 2.5 mm2 [2.1–3]. Regarding angiographic parameters, the LM area as assessed by intravascular ultrasound (IVUS) or optical coherence tomography (OCT) and the grade of stenosis as assessed by quantitative coronary angiography (QCA) were similar between groups. However, patients who required revascularization by using the two-stent technique presented more frequently with intermediate rather than low SYNTAX scores (69.4% vs. 28.4%, p < 0.0001). Also, the same group required kissing balloon inflation (KBI) more frequently (69.4% vs. 30%, p < 0.001). There were no differences regarding the success of revascularization between the use of the one-stent or two-stent technique. FFR was able to predict a SESBL > 2 mm. The cut-off value for FFR to afford the highest degree of sensitivity (74.5%) and specificity (47%) for a SESBL > 2 was >0.86, indicating a moderate accuracy (AUC = 0.61, 95% CI 0.525–0.690, p = 0.036). Conclusions: Unprotected left main PCI is a safe and effective revascularization option amongst a complex and morbid population. There were no differences regarding the success of revascularization between the use of the one-stent or two-stent technique, and there was no significant impact of KBI on side branch FFR measurements but lower side branch FFR values were correlated with angiographic side branch compromise.

Procedural Software Toolkit in the Armamentarium of Interventional Therapies: A Review of Additive Usefulness and Current Evidence

Interventional radiology is a fast-paced specialty that uses many advanced and emerging technological solutions. Several procedural hardware and software products are available commercially. Image-guided procedural software helps save time and effort in interventionist practice and adds precision to the intraoperative decisions made by the end user. Interventional radiologists, including interventional oncologists, have access to a wide range of commercially available procedural software that can be integrated into their workflow. However, the resources and real-world evidence related to such software are limited. Thus, we performed a detailed review of the current resources available, such as software-related publications, vendors' multimedia materials (e.g., user guides), and each software's functions and features, to compile a resource for interventional therapies. We also reviewed previous studies that have verified the use of such software in angiographic suites. Procedural software products will continue to increase in number and usage; these will likely be advanced further with deep learning, artificial intelligence, and new add-ins. Therefore, classifying procedural product software can improve our understanding of these entities. This review significantly contributes to the existing literature because it highlights the lack of studies on procedural product software.

Optical coherence tomography: evaluating the effects of stent boost subtract imaging on stent underexpansion in STEMI patients

Background

To evaluate the effect of stent boost subtract (SBS) imaging on stent underexpansion during percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction (STEMI) by optical coherence tomography (OCT).

Methods

One hundred thirty-eight STEMI patients who underwent drug-eluting stent (DES) implantation were prospectively recruited and divided into the SBS group (69 cases) and the CAG group (69 cases) according to whether SBS was used to guide PCI. Finally, OCT was performed on all enrolled patients, and the OCT results were used as the gold standard to evaluate the impact of standard SBS technology on stent underexpansion immediately after DES implantation.

Results

SBS identified 51 patients (24%) with stent underexpansion while OCT identified 56 patients (27.2%). SBS has a sensitivity of 80%, a specificity of 96%, a positive predictive value of 88%, and a negative predictive value of 93% for identifying stent underexpansion.

Conclusion

Compared with OCT, SBS technology is a rapid stent imaging evaluation method that can accurately quantify the stent expansion level and is time-saving and economical.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02498-9.

Computerized technologies informing cardiac catheterization and guiding coronary intervention

Advances in image processing and computer hardware have enabled the development of user-friendly software which operate in real-time and can be used in the catheterization laboratory to facilitate percutaneous coronary intervention (PCI). The two dimensional-(2D) quantitative coronary angiography (QCA) systems that have traditionally been used to assess lesion severity have been replaced by 3D-QCA systems, enabling more reliable evaluation of vessel geometry and lesion dimensions. This also allows 3D reconstruction of coronary bifurcation anatomy and generation of models that can be processed by computational fluid dynamic techniques to reliably detect flow-limiting lesions. More recently, software has been introduced that has the capability of generating a digital silhouette of the coronary arteries superimposed onto X-ray angiography to facilitate wire crossing and stent placement, and potentially reduce contrast use. In parallel, methodologies have been developed that operate with an accessible interface and can process intravascular imaging data, reliably quantify lesion severity and co-register intravascular and X-ray angiographic data to comprehensively assess plaque distribution and guide PCI. The above advances are used in daily practice to improve procedural results and outcomes. This review aims to provide an overview of the developments in the field - it presents the computer-based technologies that have been designed to accurately assess lesion severity, summarizes the advantages and limitations of the systems introduced to co-register imaging data and discusses the potential value of the existing and emerging software in the catheterization laboratory.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency

Evaluation of acute percutaneous coronary intervention (PCI) results and long-term follow-up remains challenging with ongoing stent designs. Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion, improving overall PCI results and reducing adverse cardiac events. Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results. Digital stent enhancement methods have been well validated and improved stent strut visualization. Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure. With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results. We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

Use of Stent Enhancement Technique During Percutaneous Coronary Intervention - A Case Series

Stent enhancement allows clear visualisation of implanted stents. This method, originally intended to assess stent under-expansion, can prove extremely valuable in several other situations. We present three cases illustrating its potential uses in assessment of stent failure, intraprocedural stent disruption and treatment of aorto-ostial and bifurcation lesions. Whilst stent enhancement cannot replace intravascular imaging, compared to simple angiography it can significantly improve percutaneous coronary intervention outcomes with no additional cost and with minimal procedural time.

Angioplasty of unprotected left main coronary stenosis: Real world experience of a single-operator group from eastern India

Background

Coronary artery bypass graft surgery is the standard treatment of unprotected left main coronary stenosis (ULMCA). However, in the real world scenario, many of these patients are unfit for CABG or prefer angioplasty as an alternative when offered the choice.

Methods

A total of 86 clinically stable patients with ULMCA stenosis who were unfit or unwilling for CABG underwent PCI with DES at two tertiary care centers in Kolkata. Patients were followed up prospectively for a median of 34.6 months for major adverse cardiovascular events. Angiographic follow-up was done after 1 year of index procedure or earlier, if indicated.

Results

Fifty-five patients (64%) had distal left main stenosis. Two-stent technique was used in 19 patients (22%) and single-stent technique in 36 patients (42%) with distal left main lesion. Thirteen patients (15.1%) had left ventricular ejection fraction (LVEF) of ≤45%. There was no in-hospital death, MI, or stent thrombosis. During follow-up, major adverse cardiac event (MACE) occurred in 9 patients (10.5%). Our study revealed significantly greater MACE in patients with distal left main lesion with LVEF ≤45% (50% vs 6.38%, p = 0.0002), high SYNTAX score (36.36% vs 6.82%, p = 0.008), and diabetes (17.95% vs 0.00%, p = 0.07). Overall, also patients with Diabetes, LVEF ≤ 45%, and SYNTAX score >32 had significantly higher MACE. Use of IC Stent, IVUS, or procedural strategy in distal lesion did not affect MACE.

Conclusion

In selective patients with low-intermediate SYNTAX score and without diabetes and LV dysfunction, ULMCA PCI with DES is feasible.

Repression of wall shear stress inside cerebral aneurysm at bifurcation of anterior cerebral artery by stents

The effect of a simple bare metal stent on repression of wall shear stress inside a model cerebral aneurysm was experimentally investigated by two-dimensional particle image velocimetry in vitro. The flow model simulated a cerebral aneurysm induced at the apex of bifurcation between the anterior cerebral artery and the anterior communicating artery. Wall shear stress was investigated using both stented and non-stented models to assess the simple stent characteristics. The flow behavior inside the stented aneurysm sac was unusual and wall shear stress was much smaller inside the aneurysm sac. Stent placement effectively repressed the temporal and spatial variations and the magnitude of wall shear stress. Hence, there is an effective possibility that would retard the progress of cerebral aneurysms by even simple stent.

Stent boost subtract imaging for the assessment of optimal stent deployment in coronary ostial lesion intervention: comparison with intravascular ultrasound

Percutaneous coronary intervention (PCI) of ostial lesions is complex and is technically very demanding. Intravascular ultrasound (IVUS) is considered the gold standard method to guide PCI but has several limitations. Stent boost subtract (SBS) imaging is an enhancement of the radiologic edge of the stent by digital management of regular X-ray images. The purpose of this study was to determine the availability of stent enhancement with SBS during ostial PCI by comparison with IVUS.We investigated SBS and IVUS after stent implantation in 58 ostial lesions in 55 patients. SBS and IVUS were performed in all patients to obtain improved stent location and to detect optimal release and deployment. We defined the SBS and IVUS criteria for accuracy of stent location and adequate stent deployment. IVUS findings showed that stent location was generally good. The location was accurate in 48 (82.8%) and inadequate stent deployment was observed in 10 of 58 (17.2%). Eight SBS images showed inadequate stent expansion. SBS predicted inadequate findings of IVUS with 100% specificity and 80% sensitivity, while a significant positive correlation was observed between SBS-MSA and MSA by IVUS with a regression coefficient of 0.95.Imaging techniques have a primary role during ostial PCI. SBS is a simple and quick method that offers several advantages, enabling improved stent location, adequate stent expansion, and optimal apposition of the struts to the wall. SBS imaging could be conventionally used during ostial PCI, especially in centers where IVUS is not used routinely.

First reported revascularization of complex occlusion of the right coronary artery using the IVUS-guided reverse CART technique via a gastroepiploic artery graft

When patients who have previously undergone coronary artery bypass graft surgery develop ischemia symptoms that cannot be controlled by optimal medical therapy, repeat revascularization is indicated. The revascularization strategy should be based on individual clinical and anatomical characteristics. We report here a challenging patient who presented with recurrent stable angina due to worsening of a proximal right coronary artery (RCA) stenosis to chronic total occlusion (CTO) after anastomosis of the right gastroepiploic artery (GEA) to the posterior descending artery. A soft guidewire was advanced through the right GEA collateral channel to the distal end of the CTO, but the dedicated CTO guidewires could not be advanced across the severely calcified CTO using the retrograde wire crossing or kissing wire techniques. The RCA was eventually revascularized by implantation of drug-eluting stents using the intravascular ultrasound-guided reverse controlled antegrade and retrograde subintimal tracking technique.

Efficacy of non-compliant balloon post-dilation in optimization of contemporary stents: A digital stent enhancement study

Background

There is no evidence from randomized trials for the benefit of routine non-compliant balloon (NCB) post-dilation after stent deployment. Despite being the gold standard, intravascular ultrasound is infrequently performed due to time and cost constraints and a suitable alternative technology is required for routine assessment of stent expansion. The purpose of this study was to assess the contribution of NCB post-dilation in optimizing contemporary stents by using digital stent enhancement (DSE).

Methods

We treated 120 patients with stent insertion and assessed the stents with DSE before and after NCB use. Optimal expansion was defined as the minimum stent diameter (MSD) ≥ 90% of the nominal stent diameter, an adaptation of the MUSIC and POSTIT trial criteria. Stent deployment was performed at 12 atm pressure followed by routine NCB post-dilation at ≥ 14 atm.

Results

The mean reference diameter on QCA was 2.75 mm (SD 0.63) and mean stent diameter was 3.15 mm (SD 0.46). At a mean stent deployment pressure of 11.7 atm (SD 2.4), only 21% of stents were optimally expanded. After NCB inflation at a mean of 16.9 atm (SD 2.8), MSD increased by 0.26 mm (SD 0.24), optimal stent expansion increased from 21% to 58% and mean stent symmetry ratio increased from 0.83 to 0.87 (p < 0.0001).

Conclusions

Contemporary stents are sub-optimally expanded in the majority of cases after standard deployment compared with nominal sizes. Adjunctive NCB post-dilation optimized an additional 37% of stents. DSE analysis can assist in qualitative and quantitative stent assessments and can potentially facilitate a selective NCB post-dilation strategy to achieve optimal stent expansion.

[Optical coherence tomography. Bases and applications of a new intravascular imaging technique]

Coronary angiography is the reference technique for the diagnosis of coronary disease. However, the majority of acute coronary syndromes involve angiographically non-significant lesions. It is also the technique of choice for guiding the implantation of endovascular prostheses and their later monitoring. Optical coherence tomography is an interferometric imaging technique that penetrates tissue approximately 2-3mm and provides axial and lateral resolution. It is able to distinguish different tissue types, such as fibrous, lipid-rich, necrotic, or calcified tissue. Optical coherence tomography is able to recognize a variety of features of atherosclerotic plaques that have been associated with rapid lesion progression and clinical events, such as thin cap fibroatheroma, fibrous cap thickness, dense macrophage infiltration, and thrombus formation. Currently, there is growing interest in the value of optical coherence tomography in the area of coronary intervention, where the technique offers significant advantages over more widespread intravascular diagnostic techniques such as intravascular ultrasound. Its higher resolution permits to recognize periprocedural complications, such as microdissection of the coronary artery, stent malapposition, and neointimal hyperplasia, making this tool one of the most promising techniques in the intravascular diagnosis.

Effect of myocardial contractility on hemodynamic end points under concomitant microvascular disease in a porcine model

In this study, coronary diagnostic parameters, pressure drop coefficient (CDP: ratio of trans-stenotic pressure drop to distal dynamic pressure), and lesion flow coefficient (LFC: ratio of % area stenosis (%AS) to the CDP at throat region), were evaluated to distinguish levels of %AS under varying contractility conditions, in the presence of microvascular disease (MVD). In 10 pigs, %AS and MVD were created using angioplasty balloons and 90-μm microspheres, respectively. Simultaneous measurements of pressure drop, left ventricular pressure (p), and velocity were obtained. Contractility was calculated as (dp/dt)max, categorized into low contractility <900 mmHg/s and high contractility >900 mmHg/s, and in each group, compared between %AS <50 and >50 using analysis of variance. In the presence of MVD, between the %AS <50 and >50 groups, values of CDP (71 ± 1.4 and 121 ± 1.3) and LFC (0.10 ± 0.04 and 0.19 ± 0.04) were significantly different (P < 0.05), under low-contractility conditions. A similar %AS trend was observed under high-contractility conditions (CDP: 18 ± 1.4 and 91 ± 1.4; LFC: 0.08 ± 0.04 and 0.25 ± 0.04). Under MVD conditions, similar to fractional flow reserve, CDP and LFC were not influenced by contractility.

Impact of StentBoost subtract imaging on patient radiation exposure during percutaneous coronary intervention

The purpose of this study was to assess the impact of StentBoost Subtract (SBS) imaging on patient radiation dose during percutaneous coronary intervention. Data were prospectively collected between February 2010 and November 2012 at a tertiary cardiac catheterization. All patients who had scheduled for coronary stent implantation performed by one expert interventional cardiologist with sufficient experience in SBS imaging and radiation protection, were included. The patients were divided into groups with or without SBS. A multiple linear regression analysis was used to determine the impact of SBS imaging on patient radiation dose. Of 712 patients screened, 414 patients were enrolled in the study (with SBS: n = 177, without SBS: n = 237). Although the DAP, fluoroscopy time and cine frames used in the group with SBS were significantly increased when compared with those used in the group without SBS (P < 0.05), multiple linear regression shows SBS imaging has no significant impact on patient radiation dose (P > 0.05). Multivariate predictors of patient radiation dose were the patients' BMI, B2/C lesions, number of stents placed and bifurcation stenting (P < 0.05). In selected patients, SBS imaging can be performed with comparable patient radiation dose, compared with plain fluoroscopic imaging. This may attribute to the operator's sufficient experience in SBS imaging and radiation protection.

Effect of StentBoost imaging guided percutaneous coronary intervention on mid-term angiographic and clinical outcomes

INTRODUCTION

The gold standard for evaluating stent expansion after percutaneous coronary intervention (PCI) is intravascular ultrasound (IVUS). However, the routine use of this modality is costly and time consuming. StentBoost is a new imaging technique that improves fluoroscopy-based assessments of stent expansion. The purpose of this study was to evaluate the effect of StentBoost imaging-guided PCI on mid-term angiographic and clinical outcomes.

METHODS AND RESULTS

A total of 870 consecutive patients were recruited (mean age: 64.34 ± 11.61; men: 64.5%), all of whom underwent PCI with drug-eluting stents (DESs). The subjects were divided into a no StentBoost group (n=569 patients) and a StentBoost group (n=301 patients). The 6-month angiographic and 12-month clinical outcomes were compared between the two groups. At 1 month, clinical outcomes were similar between the two groups. At 6 months, the StentBoost group had significantly lower rates of late loss (0.32 ± 0.40 vs. 0.48 ± 0.59; p=0.005) and binary restenosis (1.2% vs. 8.3%; p=0.029) compared with the no-StentBoost group. At 12 months, StentBoost group had significantly lower the incidence of target lesion revascularization (TLR) (1.7% vs. 7%; p=0.034) and TLR-major adverse cardiac events (6% vs. 13.2%; p=0.037) compared with the no-StentBoost group.

CONCLUSION

We conclude that the routine clinical use of StentBoost during PCI can be useful, and results in better medium-term angiographic and clinical outcomes.

Dislodged and mechanically distorted stent stuck within a previously implanted drug-eluting stent

Coronary stent loss during percutaneous coronary intervention is rare and is often associated with significant morbidity. Several retrieval techniques, overlying stent deployment and crushing, and surgical removal can be used to deal with a stent lost in the coronary system. We successfully treated a dislodged and mechanically distorted coil stent stuck within a previously implanted drug-eluting stent (DES) by stent-crush technique. This case might provide insight into the mechanisms responsible for the longitudinal fragility of cobalt alloy and coil-structure stents and stent fracture of DES. In the DES era, careful attention should be paid to such complications when attempting to deliver a stent to a distal vessel through a pre-existing DES.