Vascular Tissue Reaction to Acute Malapposition in Human Coronary Arteries

Impact of acute and persistent stent malapposition after percutaneous coronary intervention on adverse cardiovascular outcomes

INTRODUCTION

The association of coronary stent malapposition (SM) and adverse clinical outcomes after percutaneous coronary intervention (PCI) remains unclear. We aimed to perform a systematic review and meta-analysis of randomized and observational studies to assess the association between acute and persistent SM detected using intravascular ultrasound (IVUS) or optical coherence tomography (OCT) and adverse cardiovascular outcomes.

EVIDENCE ACQUISITION

Available studies were identified through a systematic search of PubMed, reference lists of relevant articles, and Medline. Main efficacy outcomes of interest were: device-oriented composite endpoint (DoCE, including cardiac death, myocardial infarction [MI], target lesion revascularization [TLR], and stent thrombosis [ST]), major safety events (MSE, including cardiac death, MI and ST), TLR, and ST. A sensitivity analysis regarding the impact of major malapposition was also performed.

EVIDENCE SYNTHESIS

A total of 9 studies enrolling 6497 patients were included in the meta-analysis. After a mean follow-up of 24±14 months, overall acute and/or persistent malapposition was not significantly associated with the occurrence of all the outcomes of interest, including DoCE (risk ratio [RR] 1.00, 95% confidence interval [CI, 0.79-1.26], P=0.99), MSE (RR 1.42, 95%CI [0.81-2.50], P=0.22), TLR (RR 0.84, 95%CI [0.59-1.19], P=0.33), and ST (RR 1.16, 95%CI [0.48-2.85], P=0.74). In the sensitivity analysis, we found a significant increase of MSE in patients with major malapposition (RR 2.97, 95%CI [1.51-5.87], P=0.001).

CONCLUSIONS

Acute and persistent SM were not overall associated with adverse cardiovascular clinical outcomes at follow-up. However, major malapposition was associated with an increased risk of major safety events, including cardiac death, MI and ST. These findings should be taken into account during stent implantation and PCI optimization.

Plaque burden is associated with minimal intimal coverage following drug-eluting stent implantation in an adult familial hypercholesterolemia swine model

Safety and efficacy of coronary drug-eluting stents (DES) are often preclinically tested using healthy or minimally diseased swine. These generally show significant fibrotic neointima at follow-up, while in patients, incomplete healing is often observed. The aim of this study was to investigate neointima responses to DES in swine with significant coronary atherosclerosis. Adult familial hypercholesterolemic swine (n = 6) received a high fat diet to develop atherosclerosis. Serial OCT was performed before, directly after, and 28 days after DES implantation (n = 14 stents). Lumen, stent and plaque area, uncovered struts, neointima thickness and neointima type were analyzed for each frame and averaged per stent. Histology was performed to show differences in coronary atherosclerosis. A range of plaque size and severity was found, from healthy segments to lipid-rich plaques. Accordingly, neointima responses ranged from uncovered struts, to minimal neointima, to fibrotic neointima. Lower plaque burden resulted in a fibrotic neointima at follow-up, reminiscent of minimally diseased swine coronary models. In contrast, higher plaque burden resulted in minimal neointima and more uncovered struts at follow-up, similarly to patients' responses. The presence of lipid-rich plaques resulted in more uncovered struts, which underscores the importance of advanced disease when performing safety and efficacy testing of DES.

Reciprocal assistance of intravascular imaging in three-dimensional stent reconstruction: Using cross-modal translation based on disentanglement representation

BACKGROUND

Accurate and efficient 3-dimension (3D) reconstruction of coronary stents in intravascular imaging of optical coherence tomography (OCT) or intravascular ultrasound (IVUS) is important for optimization of complex percutaneous coronary interventions (PCI). Deep learning has been used to address this technical challenge. However, manual annotation of stent is strenuous, especially for IVUS images. To this end, we aim to explore whether the OCT and IVUS images can assist each other in stent 3D reconstruction when one of them is lack of labeled dataset.

METHODS

We firstly performed cross-modal translation between OCT and IVUS images, where disentangled representation was employed to generate synthetic images with good stent consistency. The reciprocal assistance of OCT and IVUS in stent 3D reconstruction was then conducted by applying unsupervised and semi-supervised learning with the aid of synthetic images. Stent consistency in synthetic images and reciprocal effectiveness in stent 3D reconstruction were quantitatively assessed by F1-Score (FS) on two datasets: OCT-High Definition IVUS (HD IVUS) and OCT-Conventional IVUS (IVUS).

RESULTS

The employment of disentangled representation achieved higher stent consistency in synthetic images (OCT to HD IVUS: FS=0.789 vs 0.684; HD IVUS to OCT: FS=0.766 vs 0.682; OCT to IVUS: FS=0.806 vs 0.664; IVUS to OCT: FS=0.724 vs 0.673). For stent 3D reconstruction, the assistance from synthetic images significantly promoted unsupervised adaptation across modalities (OCT to HD IVUS: FS=0.776 vs 0.109; HD IVUS to OCT: FS=0.826 vs 0.125; OCT to IVUS: FS=0.782 vs 0.068; IVUS to OCT: FS=0.815 vs 0.123), and improved performance in semi-supervised learning, especially when only limited labeled data was available.

CONCLUSION

The intravascular images of OCT and IVUS can provide reciprocal assistance to each other in stent 3D reconstruction by cross-modal translation, where the stent consistency in synthetic images was maintained by disentangled representation.

Early healing after treatment of coronary lesions by thin strut everolimus, or thicker strut biolimus eluting bioabsorbable polymer stents: The SORT-OUT VIII OCT study

AIMS

Early healing after drug-eluting stent (DES) implantation may reduce the risk of stent thrombosis. The aim of this study was to compare patterns of early healing after implantation of the thin strut everolimus-eluting Synergy DES (Boston Scientific) or the biolimus-eluting Biomatix Neoflex DES (Biosensors).

METHODS AND RESULTS

A total of 160 patients with the chronic or acute coronary syndrome were randomized 1:1 to Synergy or Biomatrix DES. Optical coherence tomography (OCT) was performed at baseline and at either 1- or 3-month follow-up. The primary endpoint was a coronary stent healing index (CSHI), a weighted index of strut coverage, neointimal hyperplasia, malapposition, and extrastent lumen. A total of 133 cases had OCT follow-up and 119 qualified for matched OCT analysis. The median CSHI score did neither differ significantly between the groups at 1 month: Synergy 8.0 (interquartile range [IQR]: 3.0; 14.0) versus Biomatrix 8.5 (IQR: 4.0; 15.0) (p = 0.47) nor at 3 months: Synergy 6.5 (IQR: 2.0; 13.0) versus Biomatrix 6.0 (IQR: 4.0; 11.0) (p = 0.83). Strut coverage was 84.6% (IQR: 72.0; 97.9) for Synergy versus 77.6% (IQR: 70.1; 90.3) for Biomatrix (p = 0.15) at 1 month and 90.3% (IQR 79.0; 98.8) (Synergy) versus 83.9% (IQR: 77.5; 92.6) (Biomatrix) (p = 0.068) at 3 months. Pooled 1- and 3-month coverage was 88.6% (IQR: 74.4; 98.4) for Synergy compared with 80.7% (IQR: 73.2; 90.8) for Biomatrix (p = 0.02).

CONCLUSIONS

The early healing response after treatment with the Synergy or Biomatrix DES did not differ significantly as determined by a healing index. The Synergy DES showed overall better early stent strut coverage.

Six-months clinical and intracoronary imaging follow-up after reverse T and protrusion or double-kissing and crush stenting for the treatment of complex left main bifurcation lesions

Background

There is a debate regarding the best stent strategy for unprotected distal left main (LM) bifurcation disease. Among two-stent techniques, double-kissing and crush (DKC) is favored in current guidelines but is complex and requires expertise. Reverse T and Protrusion (rTAP) was shown to be a comparable strategy regarding short-term efficacy and safety, but with reduced procedural complexity.

Aim

To compare rTAP vs. DKC by optical coherence tomography (OCT) on the intermediate term.

Methods

52 consecutive patients with complex unprotected LM stenoses (Medina 0,1,1 or 1,1,1) were randomized to either DKC or rTAP and followed-up for a median of 189[180-263] days for clinical and OCT outcomes.

Results

At follow-up OCT showed similar change in the side branch (SB) ostial area (primary endpoint). The confluence polygon showed a higher percentage of malapposed stent struts in the rTAP group that did not reach statistical significance (rTAP: 9.7[4.4-18.3] % vs. DKC: 3[0.07-10.9] %; p = 0.064). It also showed a trend towards larger neointimal area relative to the stent area (DKC: 8.8 [6.9 to 13.4] % vs. rTAP: 6.5 [3.9 to 8.9] %; p = 0.07), and smaller luminal area (DKC: 9.54[8.09-11.07] mm² vs. rTAP: 11.21[9.53-12.42] mm²; p = 0.09) in the DKC group. The minimum luminal area in the parent vessel distal to the bifurcation was significantly smaller in the DKC group (DKC: 4.64 [3.64 to 5.34] mm² vs. rTAP: 6.76 [5.20 to 7.29] mm²; p = 0.03). This segment also showed a trend for smaller stent areas (p = 0.05 to 0.09), and a bigger neointimal area relative to the stent area (DKC: 8.94 [5.43 to 10.5]% vs. rTAP: 4.75 [0.08 to 8.5]%; p = 0.06) in the DKC patients. The incidence of clinical events was comparably low in both groups.

Conclusion

At 6-months, OCT showed a similar change in the SB ostial area (primary endpoint) in rTAP compared to DKC. There was also a trend for smaller luminal areas in the confluence polygon and the distal parent vessel, and a larger neointimal area relative to the stent area, in DKC, along with a tendency for more malapposed stent struts in rTAP.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT03714750, identifier: NCT03714750.

Identification of post-procedural optical coherence tomography findings associated with the 1-year vascular response evaluated by coronary angioscopy

Optical coherence tomography (OCT) provides higher resolution intravascular imaging and allows detailed evaluations of stent implantation sites post-percutaneous coronary intervention (PCI). Coronary angioscopy (CAS) can evaluate the vascular response after drug-eluting stent (DES) implantation. The post-PCI OCT findings that are associated with the CAS 1-year vascular response have not been known. We enrolled 168 lesions from 119 patients who underwent OCT-guided PCI using DES and follow-up CAS observation at 1 ± 0.5 year from August 2012 to December 2019. Outcome measures were sufficient neointimal coverage (NIC) defined as stent struts embedded in the neointima, subclinical intrastent thrombus, and vulnerable stented segments defined as those with angioscopic yellow or intensive yellow color 1 year after PCI. We identified the post-PCI OCT findings associated with these CAS findings. Sufficient NIC, subclinical intrastent thrombus, and vulnerable stented segment were detected in 85 lesions (51%), 47 lesions (28%), and 54 lesions (32%), respectively. A multivariate analysis demonstrated that malapposed struts were negatively associated with sufficient NIC (odds ratio 0.87; 95% CI 0.76-0.99; p = 0.029). However, no specific OCT findings immediately after PCI were associated with subclinical intrastent thrombus or vulnerable stented segment. Malapposition immediately after PCI was negatively associated with sufficient NIC at 1 year even without associations between post-PCI OCT findings and subclinical intrastent thrombus or vulnerable stented segment.

Evaluation of the apposition in unruptured aneurysms treated with flow diverters by optical coherence tomography: Preliminary clinical experience

Background

The risk of perioperative stroke and the rate of occlusion of long-term aneurysms in the treatment of unruptured aneurysms with flow diverters (FDs) are affected by stent apposition. Optical coherence tomography (OCT) may be an optional technique in evaluating apposition.

Purpose

To explore the feasibility of the OCT imaging technique in evaluating stent apposition in the clinical application of the FD for unruptured aneurysms.

Methods

OCT and Vaso CT were used in patients with indications for surgery to treat unruptured aneurysms with the FDs, to evaluate the apposition of the FDs after fully released, and to analyze OCT images for FDs apposition and compare with corresponding Vaso CT images.

Results

A total of four patients were enrolled, and OCT found malapposition after FDs placement in all four patients, and the maximum gap between the stent and vascular wall ranged from 0.68 to 1.95 mm and the length of malapposition ranged from 1.80 to 7.40 mm. However, Vaso CT found malapposition only in two of the four patients and missed malapposition near aneurysm in all three patients treated by the FD combined with coiling and could not accurately evaluate the maximum gap and the length of the malapposition.

Conclusion

The optical coherence tomography technique is a possible approach to evaluate apposition after the treatment of unruptured aneurysms by the FDs.

Intravascular imaging in coronary stent restenosis: Prevention, characterization, and management

Despite the introduction of drug-eluting stents to combat the neointimal hyperplasia that occurred after BMS implantation, in-stent restenosis is still encountered in a significant number of patients, particularly as increasingly complex lesions are tackled by percutaneous coronary intervention. Many biological and mechanical factors interplay to produce restenosis, some of which are avoidable. Intravascular imaging provided unique insights into various forms of stent-related mechanical issues that contribute to this phenomenon. From a practical perspective, intravascular imaging can therefore help to optimize the stenting procedure to avert these issues. Moreover, once the problem of restenosis eventuates, imaging can guide the management by tackling the underlying identified mechanism. Finally, it can be used to evaluate the re-intervention results. Nevertheless, with the emergence of different treatment options, more evidence is needed to define patient/lesion-specific characteristics that may help to tailor treatment selection in a way that improves clinical outcomes.

Towards a Deep-Learning Approach for Prediction of Fractional Flow Reserve from Optical Coherence Tomography

Cardiovascular disease (CVD) is the number one cause of death worldwide, and coronary artery disease (CAD) is the most prevalent CVD, accounting for 42% of these deaths. In view of the limitations of the anatomical evaluation of CAD, Fractional Flow Reserve (FFR) has been introduced as a functional diagnostic index. Herein, we evaluate the feasibility of using deep neural networks (DNN) in an ensemble approach to predict the invasively measured FFR from raw anatomical information that is extracted from optical coherence tomography (OCT). We evaluate the performance of various DNN architectures under different formulations: regression, classification—standard, and few-shot learning (FSL) on a dataset containing 102 intermediate lesions from 80 patients. The FSL approach that is based on a convolutional neural network leads to slightly better results compared to the standard classification: the per-lesion accuracy, sensitivity, and specificity were 77.5%, 72.9%, and 81.5%, respectively. However, since the 95% confidence intervals overlap, the differences are statistically not significant. The main findings of this study can be summarized as follows: (1) Deep-learning (DL)-based FFR prediction from reduced-order raw anatomical data is feasible in intermediate coronary artery lesions; (2) DL-based FFR prediction provides superior diagnostic performance compared to baseline approaches that are based on minimal lumen diameter and percentage diameter stenosis; and (3) the FFR prediction performance increases quasi-linearly with the dataset size, indicating that a larger train dataset will likely lead to superior diagnostic performance.

Incidence and characteristics of incomplete stent apposition in calcified lesions: An optical coherence tomography study

BACKGROUND

Persistent or late acquired incomplete stent apposition (ISA) may be associated with late or very late stent thrombosis following drug-eluting stent implantation. Presence of calcium at the target lesion may increase the risk of ISA even after rotational atherectomy (RA) followed by stenting with high pressure balloon inflation. The aim of this study is to examine the incidence and characteristics of ISA in heavily calcified lesions.

METHODS

A total of 52 heavily calcified coronary artery lesions requiring RA plus stenting were selected and studied. After successful ablation followed by stent implantation, optical coherence tomography (OCT) was performed to assess stent expansion and apposition. Presence or absence of ISA was examined and maximal stent strut to vessel wall distance (max SV distance) was measured. In lesions with repeated OCT at follow-up, serial changes in ISA were investigated.

RESULTS

ISA was documented in 51 of 52 (98%) lesions. Mean max SV distance was 713 ± 371 μm. In lesions with serial OCT images (n = 11), max SV distance decreased significantly (692.1 ± 420.2 to 462.5 ± 387.0 μm, P < 0.01) but persisted in all but 2 lesions (82%).

CONCLUSIONS

ISA is frequently documented in heavily calcified lesions requiring RA. Significant ISA still persisted with minimal improvement in SV distance at follow-up. Prognostic impact of the persistent ISA in such calcified lesions needs further investigations.

Incidence and natural history of coronary evagination after implanted biodegradable polymer sirolimus-eluting stent

Aims

The incidence and temporal change in coronary evagination (CE) after first-generation drug-eluting stent implantation is well established, whereas that after biodegradable polymer sirolimus-eluting stent (BP-SES) implantation has not yet been evaluated. The aim of this study is to assess the incidence and natural history of CE after BP-SES implantation.

Methods and results

In this multicenter registry, stable coronary lesions treated by Ultimaster BP-SES were evaluated by serial optical frequency domain imaging (OFDI) (at 0-1-12 or 0-3-12 months) and the incidence of CE was assessed. Coronary evagination was defined as the presence of an outward bulge in luminal vessel contour between apposed struts according to the following criteria: (i) evagination depth ≥10% of nominal stent diameter and (ii) evagination length ≥3.0 mm. Optical frequency domain imaging was obtained in 98, 47, 49, and 87 lesions at 0, 1, 3, and 12 months, respectively. Coronary evagination was observed in 20 (42.6%) and 12 (24.5%) lesions at 1 and 3 months, respectively, and all but one CE had resolved at 12 months. At 12 months, the mean CE area was almost zero and the mean malapposed stent area was also decreased. Comparison of the serial OFDI images indicated that CEs originated mostly from acute stent malapposition or coronary dissection behind the implanted stent.

Conclusions

In stable lesions, CE was occasionally observed with Ultimaster BP-SES at 1-3 months but mostly resolved within 12 months, without late-acquired stent malapposition. These findings suggest the safety and feasibility of biodegradable polymer coating on DES.

Vascular Injury After Stenting - Insights of Systemic Mechanisms of Vascular Repair

BACKGROUND

The role of circulating progenitor cells (CPC) in vascular repair following everolimus-eluting stent (EES) implantation is largely unknown. The aim of the study was to investigate the relationship between temporal variation in CPC levels following EES implantation and the degree of peri-procedural vascular damage, and stent healing, as measured by optical coherence tomography (OCT).Methods and Results:CPC populations (CD133+/KDR+/CD45low) included patients with stable coronary artery disease undergoing stent implantation, and were evaluated using a flow cytometry technique both at baseline and at 1 week. OCT evaluation was performed immediately post-implantation to quantify the stent-related injury and at a 9-month follow up to assess the mid-term vascular response. Twenty patients (mean age 66±9 years; 80% male) with EES-treated stenoses (n=24) were included in this study. Vascular injury score was associated with the 1-week increase of CD133+/KDR+/CD45low (β 0.28 [95% CI 0.15; 0.41]; P<0.001) and with maximum neointimal thickness at a 9-month follow up (β 0.008 [95% CI 0.0004; 0.002]; P=0.04). Inverse relationships between numbers of uncoated and apposed struts for the 9-month and the 1-week delta values of CD133+/KDR+/CD45low (β -12.53 [95% CI -22.17; -2.90]; P=0.011), were also found.

CONCLUSIONS

The extent of vessel wall injury influences early changes in the levels of CPC and had an effect on mid-term vascular healing after EES implantation. Early CPC mobilisation was associated with mid-term strut coverage.

Improving PCI Outcomes Using Postprocedural Physiology and Intravascular Imaging

Although clinical outcomes after percutaneous coronary intervention (PCI) are improving, the long-term risk for target vessel failure remains concerning. Although the application of intravascular imaging and physiological indexes significantly improves outcomes, their routine use in practice remains limited. Nevertheless, merely using these modalities is not enough, and to truly improve patient outcomes, optimal intravascular dimensions with minimal vascular injury should be targeted. When assessing post-PCI results using either type of physiological or imaging technology, a broad spectrum of stent- and vessel-related anomalies can be expected. As not all of these issues warrant treatment, a profound knowledge of what to expect and how to recognize and when to treat these intraluminal problems is needed. Additionally, promising new modalities such as angiography-derived coronary physiology and hybrid imaging catheters are becoming available. The authors provide an overview of the currently available tools and techniques to define suboptimal PCI and when to apply these technologies to improve outcomes.

Diagnostic Performance of High-Resolution Intravascular Ultrasound for Abnormal Post-Stent Findings After Stent Implantation - A Comparison Study Between High-Resolution Intravascular Ultrasound and Optical Coherence Tomography

BACKGROUND

High-resolution intravascular ultrasound (HR-IVUS) is the most recently developed IVUS technology, which allows the detailed assessment of intravascular structures. The aim of this study was to evaluate the diagnostic performance of HR-IVUS in the detection of abnormal post-stent findings.Methods and Results:Patients with acute coronary syndrome underwent both HR-IVUS and optical coherence tomography (OCT) for post-stent evaluations. Quantitative measurements for stented segments and qualitative assessments for abnormal post-stent findings (stent edge dissection, intrastent tissue protrusion, and incomplete stent apposition [ISA]) were performed. Forty-seven patients underwent both HR-IVUS and OCT after stent implantation. HR-IVUS identified a larger minimal lumen area and a larger minimal lumen diameter than OCT (6.66±1.98 mm²vs. 5.61±1.79 mm²and 2.87±0.42 mm vs. 2.63±0.43 mm, respectively; both P<0.001). The sensitivity of HR-IVUS for the identification of stent edge dissection, intrastent tissue protrusion, and ISA were 20.0%, 48.9%, and 27.2%, respectively.

CONCLUSIONS

In terms of post-stent evaluation, the diagnostic performance of HR-IVUS remains insufficient. Abnormal post-stent findings might be underestimated when performing HR-IVUS due to its low sensitivity.

Clinical Implications of Post-Stent Optical Coherence Tomographic Findings: Severe Malapposition and Cardiac Events

OBJECTIVES

This study sought to evaluate the impact of post-stent optical coherence tomography (OCT) findings, including severe malapposition, on long-term clinical outcomes.

BACKGROUND

Suboptimal OCT findings following percutaneous coronary intervention (PCI) are highly prevalent; however, their clinical implications remain controversial.

METHODS

Of the patients registered in the Yonsei OCT registry, a total of 1,290 patients with 1,348 lesions, who underwent OCT immediately post-stenting, were consecutively enrolled for this study. All patients underwent implantation of drug-eluting stents. Post-stent OCT findings were assessed to identify predictors of device-oriented clinical endpoints (DoCE), including cardiac death, target vessel-related myocardial infarction (MI) or stent thrombosis, and target lesion revascularization (TLR). Significant malapposition criteria associated with major safety events (MSE) were also investigated, such as cardiac death, target vessel-related MI, or stent thrombosis.

RESULTS

The median follow-up period was 43.0 months (interquartile range [IQR] 21.4 to 56.0 months). The incidence rates of stent edge dissection, tissue prolapse, thrombus, and malapposition after intervention were not associated with occurrence of DoCE. However, patients with significant malapposition (total malapposition volume [TMV] ≥7.0 mm³] exhibited more frequent MSE. A smaller minimal stent area (MSA) was identified as an independent predictor for DoCE (hazard ratio [HR]: 1.20 [95% confidence interval [CI]: 1.00 to 1.43]; p = 0.045). Malapposition with TMV ≥7.0 mm³ was found to be an independent predictor of MSE (HR: 6.12 [95% CI: 1.88 to 19.95]; p = 0.003). Follow-up OCT at 3, 6, or 9 months after PCI showed that post-stent TMV ≥7.0 mm³ was related to a greater occurrence of late malapposition and uncovered struts.

CONCLUSIONS

Although most suboptimal OCT findings were not associated with clinical outcomes, a smaller MSA was associated with DoCE, driven mainly by TLR, and significant malapposition with TMV ≥7.0 mm³ was associated with more MSE after PCI. (Yonsei OCT [Optical Coherence Tomography] Registry for Evaluation of Efficacy and Safety of Coronary Stenting; Yonsei OCT registry; NCT02099162).

STENTYS coronary system: current status and future direction

Stentys self-apposing stent was designed to face complex lesions in the precincts of percutaneous coronary interventions. Nitinol platform and disconnectable struts were designed to provide a complete apposition on the vessel wall in challenging lesions such as significant tapering, primary angioplasty in ST segment elevation myocardial infarction and bifurcation. Stentys X-position S is a sirolimus eluting stent with a novel delivery system aiming to improve positioning. Clinical trials showed good results in terms of procedural success rate, clinical outcome and short-term strut apposition. Nevertheless, Stentys stent did not show superiority over the conventional balloon-expandable stents in the clinical outcomes. Authors underlined the importance of a learning curve and an adequate training period to get familiar with the device's features. Future trials in an all-comer population using the novel X-Position S stent will confirm the preliminary findings and strengthen evidence in clinical practice.

Temporal changes of incomplete stent apposition during early phase after everolimus-eluting stent implantation: serial optical coherence tomography analyses at 2-week and 4-month

The healing process of acute incomplete stent apposition (ISA) in the early phase after stent implantation has not been well understood. We evaluated the temporal changes of ISA during the early phase after everolimus-eluting stent (EES) implantation using serial optical coherence tomography (OCT) analyses. Serial OCT examinations were performed immediately post-stenting and 2-week and 4-month after EES implantation for patients with ST-segment elevation myocardial infarction. At the most proximal cross-section of the implanted stent, the prevalence of ISA and maximum ISA distance were serially evaluated. In 45 patients with ST-segment elevation myocardial infarction, serial OCT analyses at 2-week and 4-month were performed. The prevalence of ISA gradually decreased over time, being 53.3% at baseline, 37.8% at 2-week follow-up, and 11.1% at 4-month follow-up (P < 0.001). The maximum ISA distance also decreased over time (P < 0.001). A receiver-operating curve analysis found that the optimal cut-off values of the baseline ISA distance for predicting persistent ISA at 2-week follow-up and 4-month follow-up were > 140 µm and > 215 µm, respectively. The baseline ISA distance was closely associated with the healing of ISA in the early phase after EES implantation. Maintaining the minimum ISA distance at post-stenting facilitates early phase healing of acute ISA.

Automatic stent reconstruction in optical coherence tomography based on a deep convolutional model

Intravascular optical coherence tomography (IVOCT) can accurately assess stent apposition and expansion, thus enabling the optimisation of a stenting procedure to minimize the risk of device failure. This paper presents a deep convolutional based model for automatic detection and segmentation of stent struts. The input of pseudo-3D images aggregated the information from adjacent frames to refine the probability of strut detection. In addition, multi-scale shortcut connections were implemented to minimize the loss of spatial resolution and refine the segmentation of strut contours. After training, the model was independently tested in 21,363 cross-sectional images from 170 IVOCT image pullbacks. The proposed model obtained excellent segmentation (0.907 Dice and 0.838 Jaccard) and detection metrics (0.943 precision, 0.940 recall and 0.936 F1-score), significantly better than conventional features-based algorithms. This performance was robust and homogenous among IVOCT pullbacks with different sources of acquisition (clinical centres, imaging operators, type of stent, time of acquisition and challenging scenarios). In addition, excellent agreement between the model and a commercialized software was observed in the quantification of clinically relevant parameters. In conclusion, the deep-convolutional model can accurately detect stent struts in IVOCT images, thus enabling the fully-automatic quantification of stent parameters in an extremely short time. It might facilitate the application of quantitative IVOCT analysis in real-world clinical scenarios.

Diagnostic accuracy and reproducibility of optical flow ratio for functional evaluation of coronary stenosis in a prospective series

BACKGROUND

Evaluating prospectively the feasibility, accuracy and reproducibility of optical flow ratio (OFR), a novel method of computational physiology based on optical coherence tomography (OCT).

METHODS AND RESULTS

Sixty consecutive patients (76 vessels) underwent prospectively OCT, angiography- based quantitative flow ratio (QFR) and fractional flow ratio (FFR). OFR was computed offline in a central core-lab by analysts blinded to FFR. OFR was feasible in 98.7% of the lesions and showed excellent agreement with FFR (ICCa = 0.83, r = 0.83, slope = 0.80, intercept = 0.17, kappa = 0.84). The area under curve to predict an FFR ≤ 0.80 was 0.95, higher than for QFR (0.91, p = 0.115) and for minimal lumen area (0.64, p < 0.001). Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio were 93%, 92%, 93%, 88%, 96%, 13.8, 0.1, respectively. Median time to obtain OFR was 1.07 (IQR: 0.98-1.16) min, with excellent intraobserver and interobserver reproducibility (0.97 and 0.95, respectively). Pullback speed had negligible impact on OFR, provided the same coronary segment were imaged (ICCa = 0.90, kappa = 0.697).

CONCLUSIONS

The prospective computation of OFR is feasible and reproducible in a real-world series, resulting in excellent agreement with FFR, superior to other image-based methods.

In-stent Restenosis in an Anomalous Left Main Coronary Artery Arising from the Right Sinus of Valsalva After a Stenting Lesion with Acute Angle

We describe a 38-year-old male who underwent percutaneous coronary intervention (PCI) using a third-generation drug-eluting stent (DES) with a thin stent for an anomalous left main coronary artery (LMCA) originating from the right coronary sinus with a retro-aortic course. Six months later, in-stent restenosis (ISR) occurred due to stent implantation in angled lesions with significant hinge motion. An intravascular ultrasound (IVUS) revealed significant neointimal hyperplasia. The vessel wall of an angled coronary artery lesion is exposed to mechanical stress from the deployed stent. It has been reported before in the major coronary arteries but not in an anomalous LMCA.

Cut-off value of strut-vessel distance for the resolution of acute incomplete stent apposition in the early phase using serial optical coherence tomography after cobalt-chromium everolimus-eluting stent implantation

OBJECTIVE

The purpose of this study was to identify a cut-off value to predict the resolution of incomplete-stent-apposition (ISA) after cobalt-chromium everolimus-eluting stent (CoCr-EES) implantation at early follow-up.

BACKGROUND

To date, appropriate stent apposition at the acute period using intracoronary imaging has been recommended because persistent ISA is considered to be a risk factor for stent thrombosis. We examined the indices for resolving acute ISA. In particular, we determined the cut-off value for strut vessel distance (SV-distance) as visualized by optical coherence tomography (OCT) at 8 months after CoCr-EES implantation. However, the cut-off value of SV-distance for the earlier resolution of ISA is unclear.

METHODS

A total of 95 cases and 103 stents were registered in the MECHANISM Elective substudy. The SV-distance was measured at the deepest site of the target malapposition and every 1 mm from the proximal edge to the distal edge of the mal-apposed area using OCT. Cut-off values for ISA resolution at 1 and 3 months were estimated by SV-distance using receiver operating characteristic analysis.

RESULTS

The total number of analyzed struts was 14,418 at the 1-month follow-up and 11,986 at the 3-month follow-up. The optimal SV-distance cut-off values just after stent implantation to predict ISA resolution were 185 µm at the 1-month follow-up and 195 μm at the 3-month follow-up.

CONCLUSION

For resolution of ISA, SV-distance cut-off values of 185 µm at 1 month postimplantation and 195 μm at 3 months postimplantation can be used as the index of endpoint of the percutaneous coronary intervention.

Impact of lesion angle on optical coherence tomography findings and clinical outcomes after drug-eluting stent implantation in curved vessels

Tortuous coronary lesions are associated with adverse outcomes after implantation of bare metal or first-generation drug-eluting stents (DESs). We investigated the impact of lesion angle on vessel wall injuries and stent apposition as assessed by optical coherence tomography (OCT) after second- and newer-generation DES implantation. We investigated 95 de novo lesions treated with a single DES (62 platinum-chromium everolimus-eluting stents and 33 bioresorbable-polymer sirolimus-eluting stents). Post-intervention OCT findings were compared between angled lesions (≥ 45°; n = 33) and non-angled lesions (< 45°; n = 62). The 12-month clinical outcomes were also compared between the groups. Cross-sectional OCT analysis revealed that compared to non-angled lesions, angled ones had a significantly higher incidence of intra-stent dissection around the centre of the angle (19.7% vs. 10.8%, p = 0.01) and incomplete stent apposition (ISA) in the distal and proximal sub-segments (10.0% vs. 4.1%, p = 0.002; 15.3% vs. 7.9%, p < 0.001, respectively). Strut-based analysis also showed that angled lesions demonstrated a higher rate of malapposed strut in the distal and proximal sub-segments (3.0% vs. 0.9%, p < 0.001; 4.3% vs. 1.8%, p < 0.001, respectively). The 12 month clinical outcomes were comparable between the groups. Compared to non-angled lesions, angled coronary lesions were associated with a higher incidence of intra-stent dissection and ISA on post-intervention OCT after implantation of second- and newer-generation DESs.

Cut-off value of mal-apposition volume and depth for resolution at early phase of acute incomplete stent apposition after CoCr-EES implantation

The purpose of this study was to clarify a cut-off value for acute incomplete stent apposition (ISA) volume and maximum-depth to predict ISA resolution at 1- and 3-month follow-up in patients treated with cobalt-chromium everolimus-eluting stents. In total, 95 cases and 103 stents were registered in the MECHANISM-Elective sub-study. Acute ISA-volume was measured by the trapezoid rule. ISA resolution of cut-off value at 1- and 3-month was estimated by ISA-volume and maximum-depth using receiver operatorating characteristic curve analysis. The total number of analysed acute ISAs was 202 in the 1-month group and 225 in the 3-month group. A total of 123 ISAs at 1-month and a total of 169 ISAs at 3-month had been resolved. The cut-off value of ISA resolution by ISA-volume was 0.169 mm³ at 1-month (AUC: 0.725, sensitivity: 72.2%, specificity: 61.0%) and 0.295 mm³ at 3-month (AUC: 0.757, sensitivity: 75.0%, specificity: 60.4%). The cut-off value of ISA resolution by ISA maximum-depth demonstrated was 0.285 mm at 1-month (area under curve (AUC): 0.789, sensitivity: 70.9%, specificity: 69.9%) and 0.305 mm at 3-month (AUC: 0.663, sensitivity: 60.7%, specificity: 66.9%). Incidence of ISA resolution was significantly lower in combination with cut-off values of ISA-volume and maximum-depth (33%, p < 0.001, at 1-month; 56%, p = 0.003, at 3-month). Combining the cut-off value of ISA-volume with the maximum-depth might be helpful to consider the endpoint of the PCI procedure.

Severe Acute Stent Malapposition After Drug-Eluting Stent Implantation: Effects on Long-Term Clinical Outcomes

Background

The effects of severe acute stent malapposition (ASM) after drug‐eluting stent implantation on long‐term clinical outcomes are not clearly understood. We evaluated long‐term clinical outcomes of severe ASM using optical coherence tomography.

Methods and Results

We pooled patient‐ and lesion‐level data from 6 randomized studies. Five studies investigated follow‐up drug‐eluting stent strut coverage and one investigated ASM. In this data set, a total of 436 patients with 444 lesions underwent postintervention optical coherence tomography examination and these data were included in the analysis. Severe ASM was defined as lesions with ≥400 μm of maximum malapposed distance or ≥1 mm of maximum malapposed length. Composite events (cardiac death, target lesion–related myocardial infarction, target lesion revascularization, and stent thrombosis) were compared between patients with and without severe ASM. The postintervention optical coherence tomography findings indicated that 62 (14.2%) patients had lesions with ≥400 μm of maximum malapposed distance and 186 (42.7%) patients had lesions with ≥1 mm of maximum malapposed length. The 5‐year clinical follow‐up was completed in 371 (86.1%) of the eligible 431 patients. The cumulative rate of composite events was similar among the patients in each group during 5‐year follow‐up: 3.3% in patients with ASM ≥400 μm of maximum malapposed distance versus 3.1% in those with no ASM or ASM <400 μm of maximum malapposed distance (P=0.89), and 1.2% in patients with ASM ≥1 mm of maximum malapposed length versus 4.6% in those with no ASM or ASM <1 mm of maximum malapposed length (P=0.06).

Conclusions

During the 5‐year follow‐up, ASM severity was not associated with long‐term clinical outcomes in patients treated with drug‐eluting stents.

Long-Term Clinical Outcomes of Late Stent Malapposition Detected by Optical Coherence Tomography After Drug-Eluting Stent Implantation

Background

The relationship between late stent malapposition (LSM) and adverse cardiovascular events is controversial. Studies are needed to evaluate long‐term (>5 years) clinical outcomes of LSM detected by optical coherence tomography (OCT) after drug‐eluting stent implantation.

Methods and Results

We investigated long‐term clinical outcomes of OCT‐detected LSM in 351 patients who received drug‐eluting stents and were examined by both poststent and follow‐up OCT (175±60 days after drug‐eluting stent implantation) from January 2009 to December 2011. LSM was observed in 99 patients (28%). We evaluated the cumulative rate of composite events (cardiovascular death, target‐vessel–related myocardial infarction, target‐vessel revascularization, and stent thrombosis). During 80.1±24.5 months of follow‐up, very late stent thrombosis did not occur in any patients with LSM. The cumulative 8‐year rate of composite events was 7.3% in patients with LSM and 10.5% in patients without LSM (P=0.822, log‐rank test). We further divided patients into the following 4 groups: patients with both late‐persistent and late‐acquired stent malapposition (n=23), patients with late‐persistent stent malapposition alone (n=45), patients with late‐acquired stent malapposition alone (n=31), and patients without LSM (n=252). The cumulative 8‐year rates of composite events were similar among these 4 groups (0%, 9.6%, 9.7%, and 10.5%, respectively; P=0.468 by log‐rank test).

Conclusions

During long‐term follow‐up (>5 years), very late stent thrombosis did not occur in patients with OCT‐detected LSM. The rates of adverse clinical events were similar between patients with LSM versus those without LSM. Presence of OCT‐detected LSM was not associated with unfavorable clinical outcomes.

See Editorial by Ali et al

The "Oculo-Appositional Reflex": Should Optical Coherence Tomography-Detected Stent Malapposition Be Corrected?

See Article by Im et al

Numerical study of incomplete stent apposition caused by deploying undersized stent in arteries with elliptical cross-sections

Incomplete stent apposition (ISA) is one of the causes leading to post-stent complications, which can be found when an undersized or under-expanded stent is deployed at lesions. Previous research efforts have focused on ISA in idealized coronary arterial geometry with circular cross-sections. However, arterial cross-section eccentricity plays an important role in both location and severity of ISA. Computational fluid dynamics (CFD) simulations are carried out to systematically study the effects of ISA in arteries with elliptical cross-sections, as such stents are partially embedded on the minor axis sides of the ellipse and malapposed elsewhere. Overall, ISA leads to high time-averaged WSS (TAWSS) at the proximal end of the stent and low TAWSS at the ISA transition region and the distal end. Shear rate depends on both malapposition distance and blood stream locations, which is found to be significantly higher at the inner stent surface than the outer surface. The proximal high shear rate signifies increasing possibility in platelet activation, when coupled with low TAWSS at the transition and distal region which may indicate a nidus for in-stent thrombosis.

Implications of the local hemodynamic forces on the formation and destabilization of neoatherosclerotic lesions

OBJECTIVE

To examine the implications of endothelial shear stress (ESS) distribution in the formation of neoatherosclerotic lesions.

METHODS

Thirty six patients with neoatherosclerotic lesions on optical coherence tomography (OCT) were included in this study. The OCT data were used to reconstruct coronary anatomy. Blood flow simulation was performed in the models reconstructed from the stent borders which it was assumed that represented the lumen surface at baseline, immediate after stent implantation, and the estimated ESS was associated with the neointima burden, neoatherosclerotic burden and neointima characteristics. In segments with neointima rupture blood flow simulation was also performed in the model representing the lumen surface before rupture and the ESS was estimated at the ruptured site.

RESULTS

An inverse association was noted between baseline ESS and the incidence and the burden of neoatherosclerotic (β = -0.60, P < 0.001, and β = -4.05, P < 0.001, respectively) and lipid-rich neoatherosclerotic tissue (β = -0.54, P < 0.001, and β = -3.60, P < 0.001, respectively). Segments exposed to low ESS (<1 Pa) were more likely to exhibit macrophages accumulation (28.2% vs 10.9%, P < 0.001), thrombus (11.0% vs 2.6%, P < 0.001) and evidence of neointima discontinuities (8.1% vs 0.9%, P < 0.001) compared to those exposed to normal or high ESS. In segments with neointima rupture the ESS was high at the rupture site compared to the average ESS over the culprit lesion (4.00 ± 3.65 Pa vs 3.14 ± 2.90 Pa, P < 0.001).

CONCLUSIONS

Local EES is associated with neoatherosclerotic lesion characteristics, which suggests involvement of ESS in the formation of vulnerable plaques in stented segments.

Quantification of thrombus formation in malapposed coronary stents deployed in vitro through imaging analysis

Stent thrombosis is a major complication of coronary stent and scaffold intervention. While often unanticipated and lethal, its incidence is low making mechanistic examination difficult through clinical investigation alone. Thus, throughout the technological advancement of these devices, experimental models have been indispensable in furthering our understanding of device safety and efficacy. As we refine model systems to gain deeper insight into adverse events, it is equally important that we continue to refine our measurement methods. We used digital signal processing in an established flow loop model to investigate local flow effects due to geometric stent features and ultimately its relationship to thrombus formation. A new metric of clot distribution on each microCT slice termed normalized clot ratio was defined to quantify this distribution. Three under expanded coronary bare-metal stents were run in a flow loop model to induce clotting. Samples were then scanned in a MicroCT machine and digital signal processing methods applied to analyze geometric stent conformation and spatial clot formation. Results indicated that geometric stent features play a significant role in clotting patterns, specifically at a frequency of 0.6225 Hz corresponding to a geometric distance of 1.606 mm. The magnitude-squared coherence between geometric features and clot distribution was greater than 0.4 in all samples. In stents with poor wall apposition, ranging from 0.27 mm to 0.64 mm maximum malapposition (model of real-world heterogeneity), clots were found to have formed in between stent struts rather than directly adjacent to struts. This early work shows how the combination of tools in the areas of image processing and signal analysis can advance the resolution at which we are able to define thrombotic mechanisms in in vitro models, and ultimately, gain further insight into clinical performance.

Optical coherence tomography follow-up 18 months after titanium-nitride-oxide-coated versus everolimus-eluting stent implantation in patients with acute coronary syndrome

Background Inadequate neointimal coverage of stent struts is associated with late stent thrombosis. Purpose To demonstrate the extent of neointimal coverage and strut malapposition in titanium-nitride-oxide-coated bioactive stents (BAS) versus everolimus-eluting stents (EES) by optical coherence tomography (OCT) performed at 18-month follow-up. Material and Methods In the BASE-ACS trial, 827 patients presenting with acute coronary syndrome were randomized to receive either BAS or EES. Forty patients (20 BAS, 20 EES) underwent OCT at 18-month follow-up for evaluation of stent strut coverage, malapposition, and neointimal hyperplasia (NIH). Primary endpoint was binary stent strut coverage (ratio of covered struts to all analyzed struts multiplied by 100). Co-primary endpoint was the percentage of malapposed struts. Results We analyzed 3465 struts in 330 cross-sections of BAS and 3327 struts in 316 cross-sections of EES. Binary stent strut coverage, based on strut-level analysis, was higher with BAS versus EES (99.5% versus 94.2%, respectively; P < 0.001), the strut-level percentage of malapposed struts was lower with BAS (0.6% versus 2.5%, respectively; P < 0.001). Yet, the mean NIH thickness was greater with BAS (237 ± 125 versus 108 ± 62 µm, respectively; P < 0.001). Conclusion In the current post-hoc analysis with OCT performed at 18 months, binary strut coverage, based on strut-level analysis, was higher with BAS versus EES; strut-level malapposed struts were fewer with BAS; yet, BAS induced thicker NIH.

Application of an enhanced device to transluminal retrieval of malappositioned coronary stents: An experimental study

OBJECTIVES

This study investigated the application of a novel enhanced device to retrieval of deployed stents in a porcine coronary model.

BACKGROUND

Recurrence of in-stent restenosis and stent thrombosis still remains to be resolved. Under these conditions, it is sometimes necessary to retrieve malfunctional stents responsible for thrombosis. However, few data exist regarding the feasibility and safety of retrieval device use in previously deployed coronary stents.

METHODS

We have developed an enhanced device consisting of an asymmetric forceps, conducting shaft (1.6 mm diameter, 150 cm length), and control handle. Bare-metal stents (3 mm diameter) were implanted in four pigs to create a malapposition model. Coronary artery injury was evaluated by intravascular ultrasound (IVUS) and histological imaging on the first and 14th days.

RESULTS

The device was delivered to the coronary artery using the existing catheter (7 Fr). After opening the forceps, the blade was forced into the space between the vessel wall and the stent, and the stent struts were then grasped with the forceps. This was then pulled back into the catheter, still grasping the stent struts with the forceps. All stents were successfully retrieved by this method (n = 4). On the first day, no apparent vessel wall injury was detectable by IVUS, although histological findings revealed damage to endothelial monolayer on retrieval of deployed stent. On the 14th day, mild intimal thickening was observed by IVUS and histology.

CONCLUSIONS

These results demonstrate that the present device can be applied to transluminal retrieval of acquired malappositioned coronary stents.

The fate of incomplete scaffold apposition of everolimus-eluting bioresorble scaffolds: A serial optical coherence tomography analysis

BACKGROUND

Incomplete stent apposition (ISA) can be divided into acute and late forms. Late ISA may be due to persistent ISA or late-acquired ISA (LAISA). This study evaluated the natural course of ISA after bioresorbable vascular scaffold (BRS) implantation using optical coherence tomography (OCT).

METHODS

Thirty-two patients (45 BRS) were assessed immediately after BRS implantation and 1 year thereafter using OCT. Acute ISA identified after BRS implantation but absent at follow-up was defined as resolved; otherwise, it was considered persistent. LAISA was defined as newly developed ISA that was identified at follow-up despite complete apposition immediately after BRS implantation. Intra-BRS fibrin-like material (IBF) was identified as an irregular intraluminal mass. ISA percentage was expressed as follows: (number of ISA/total number of BRS struts)×100.

RESULTS

Among 45 BRS and 15,894 analyzed BRS struts, 34 and 882 had acute ISA post-procedure, respectively. At follow-up, 92 of 15,364 analyzed struts exhibited late ISA (64 persistent ISA and 28 LAISA). In 15 of 28 struts with LAISA, LAISA occurred at the sites adjacent to post-interventional dissection. Uncovered struts were more frequently observed in late ISA compared to apposed struts (3.7±4.8 vs. 0.58±2.2%, p=0.09). IBF was significantly more common in BRS with late ISA (62.5 vs. 8.1%, p=0.02). Receiver-operating characteristic curve analysis identified a cut-off value of 280μm for acute ISA distance predicting persistent ISA.

CONCLUSION

Resolution of acute ISA after BRS is common. The occurrence of LAISA may be infrequent and may be a nidus of stent thrombosis.

Neointimal Healing Evaluated by Optical Coherence Tomography after Drug-Eluting Absorbable Metal Scaffold Implantation in de novo Native Coronary Lesions: Rationale and Design of the Magmaris-OCT Study

Objectives: We sought to explore neointimal healing assessed by optical coherence tomography (OCT) following implantation of the Magmaris sirolimus-eluting absorbable metal scaffold. Methods: The Magmaris-OCT is a prospective, multicenter, single-arm observational clinical study, intended to enrol 60 consecutive patients with up to 2 de novo native coronary lesions, each located in different major epicardial vessels, with a reference vessel diameter of 2.5-3.5 mm, and a maximum lesion length of 20 mm. Patients will undergo Magmaris scaffold implantation in the target lesion, according to the standard practice. Clinical follow-up will take place at 30 days, and at 3, 6, 9, and 12 months. For invasive-imaging follow-up, patients will be classified into 3 groups: cohort A will be scheduled for follow-up at 3 months, cohort B at 6 months, and cohort C at 12 months. Invasive imaging will include quantitative coronary angiography, OCT evaluation, and coronary flow reserve measurement. The primary end point will be the percentage of uncovered scaffold struts assessed by OCT at the prespecified follow-up. Conclusions: This study will provide insight into the short- and mid-term healing properties following Magmaris scaffold implantation, with special emphasis on the neointimal coverage of scaffold struts.

Classification of mechanisms of strut malapposition after angiographically optimized stent implantation: An optical coherence tomography study

AIMS

To elucidate causes and extent of strut malapposition in angiographically optimized stenting.

METHODS AND RESULTS

Using a new classification system for strut malapposition, the mechanisms of stent strut malapposition were classified as localized lumen enlargement, vessel asymmetry, stent undersizing, strut underexpansion and stent deployment issue. Stent implantations (n = 110) in 100 consecutive patients undergoing optical coherence tomography (OCT) after the operator considered the stent as optimally deployed angiographically were reviewed to determine if strut apposition was complete. 127,894 stent struts in 110 stents were analyzed. There were 6,644 struts malapposed (5.2% ±7.3%), with strut malapposition found in 82 of 110 stents (74.5%). Localized lumen enlargement was the most common cause of malapposition (74.4% of malapposition clusters). Stent undersizing was the second most common cause (46.3%) followed by strut under-expansion in 29.3%, stent deployment issue in 18.2%, and vessel asymmetry in 9.7%.

CONCLUSION

Malapposition of any degree is common after angiographic stent optimization, occurring in up to three-quarters of stents. The most frequent mechanism was localized lumen enlargement. The second most common cause of strut malapposition was stent undersizing, which was angiographically invisible. Whether performing OCT after angiographic optimization improves short- and long-term outcomes requires further study. © 2017 Wiley Periodicals, Inc.

Usefulness of Post-coronary Dilation to Prevent Recurrent Myocardial Infarction in Patients Treated With Percutaneous Coronary Intervention for Acute Coronary Syndrome (from the BASE ACS Trial)

Stent underexpansion is associated with worse outcome after stent implantation. Whether post-dilation (PD) improves outcome in patients with acute coronary syndrome (ACS) remains unclear. We performed post hoc analysis of outcome in patients from the BASE ACS (A prospective randomized comparison of titanium-nitride-oxide-coated bioactive stents with everolimus-eluting stents in acute coronary syndrome) trial who underwent PD versus those who did not. The BASE ACS trial randomized 827 patients (1:1) with ACS to receive either titanium-nitride-oxide-coated bioactive stents or everolimus-eluting stents. The primary end point was major adverse cardiac events (MACE): a composite of cardiac death, nonfatal myocardial infarction (MI), or ischemia-driven target lesion revascularization. Follow-up was planned at 12 months and yearly thereafter for up to 7 years. Of 827 patients enrolled in the BASE ACS trial, 357 (43.2%) underwent PD. Median follow-up duration was 5 years. Patients who underwent PD had less frequent nonfatal MI events at long-term follow-up, compared with those who did not (4.5% vs 8.5%, respectively, p = 0.02). The rates of MACE (15.7% vs 15.1%, respectively, p = 0.81), and the other endpoints, were not significantly different (p >0.5 for all). The results were consistent in propensity score-matched analysis (270 pairs). In patients treated with bioactive stents, those who underwent PD had a trend for a fewer nonfatal MI events (p = 0.076). Comparably, in patients treated with everolimus-eluting stents, MACE and all the individual end points were comparable (p >0.5 for all). In conclusion, patients treated with early percutaneous coronary intervention for ACS who underwent PD had less frequent nonfatal MI events at long-term follow-up, compared with those who did not; MACE rates were not significantly different.