Culprit lesion thrombus burden after manual thrombectomy or percutaneous coronary intervention-alone in ST-segment elevation myocardial infarction: the optical coherence tomography sub-study of the TOTAL (ThrOmbecTomy versus PCI ALone) trial

Treatment and Care of Patients with ST-Segment Elevation Myocardial Infarction-What Challenges Remain after Three Decades of Primary Percutaneous Coronary Intervention?

Primary percutaneous coronary intervention (pPCI) has revolutionized the prognosis of ST-segment elevation myocardial infarction (STEMI) and is the gold standard treatment. As a result of its success, the number of pPCI centres has expanded worldwide. Despite decades of advancements, clinical outcomes in STEMI patients have plateaued. Out-of-hospital cardiac arrest and cardiogenic shock remain a major cause of high in-hospital mortality, whilst the growing burden of heart failure in long-term STEMI survivors presents a growing problem. Many elements aiming to optimize STEMI treatment are still subject to debate or lack sufficient evidence. This review provides an overview of the most contentious current issues in pPCI in STEMI patients, with an emphasis on unresolved questions and persistent challenges.

The Use of Thrombectomy during Primary Percutaneous Coronary Intervention: Resurrecting an Old Concept in Contemporary Practice

Optimal myocardial reperfusion during primary percutaneous coronary intervention (pPCI) is increasingly recognized to be beyond restoring epicardial coronary flow. Both invasive and non-invasive tools have highlighted the limitation of using this metric, and more efforts are focused towards achieving optimal reperfusion at the level of the microcirculation. Recent data highlighted the close relationship between thrombus burden and impaired microcirculation in patients presenting with ST-segment elevation myocardial infarction (STEMI). Moreover, distal embolization was an independent predictor of mortality in patients with STEMI. Likewise, the development of no-reflow phenomenon has been directly linked with worse clinical outcomes. Adjunctive thrombus aspiration during pPCI is intuitively intended to remove atherothrombotic material to mitigate the risk of distal embolization and the no-reflow phenomenon (NRP). However, prior trials on the use of thrombectomy during pPCI did not support its routine use, with comparable clinical endpoints to patients who underwent PCI alone. This article aims to review the existing literature highlighting the limitation on the use of thrombectomy and provide future insights into trials investigating the role of thrombectomy in contemporary pPCI.

Effect of optimized thrombus aspiration on myocardial perfusion and prognosis in acute ST-segment elevation myocardial infarction patients with primary percutaneous coronary intervention

Objective

To investigate the impact of optimized thrombus aspiration on myocardial perfusion, prognosis, and safety in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention(primary PCI).

Methods

A total of 129 patients with STEMI were randomly allocated into control group (Subgroup A and B) and experimental group(Subgroup C and D). Control group received percutaneous transluminal coronary angioplasty (PTCA),thrombus aspiration and primary PCI. Experimental group received optimized thrombus aspiration and primary PCI. The number of thrombus aspiration was less than 4 times in Subgroup A and C. The number of thrombus aspiration was performed more than 4 times in Subgroups B and D. The classification of thrombi extracted, the TIMI flow grade, the incidence of no-reflow and slow flow, cTFC, TPI and CK-MB at 12 h and 24 h after stenting, ST segment resolution of ECG after stenting, NT-proBNP, LVEFat 24 h, 30 days and 180 days after stenting were compared between groups. The incidence of intraoperative and postoperative bleeding complications, stroke events and major cardiovascular events (MACE) were recorded and compared between groups.

Results

The classification of thrombi extracted in the experimental group was higher than that in the control group. The TIMI flow grade of the experimental group was better than the control group after thrombus aspiration. After stenting, the advantage still existed, but the difference was not statistically significant. On cTFC, the experimental group was lower than the control group, but the difference was not statistically significant; After stenting the experimental group was significantly lower than the control group. The CK-MB at 12 h and 24 h of the experimental group was lower than the control group. After thrombus aspiration the incidence of no-reflow in the experimental group was significantly lower than that in the control group; after stenting the incidence of no-reflow in the experimental group was still lower than the control group, but no statistically difference. After thrombus aspiration and stenting the incidence of slow flow in the experimental group were lower than that in the control group. After stenting, NT-proBNP at 24 h was lower in the experimental group than that in the control group, However, there was no statistical difference; after stenting, The NT-proBNP in the experimental group was lower than that in the control group at 30 days and 180 days. After stenting, LVEF of the experimental group was significantly higher than the control group at 24 h and 30 days; superiority remained after 180 days but no statistical difference. There was no statistical difference between two groups for intraoperative and postoperative bleeding complications, stroke events, and MACE events. In Subgroup analysis,there was no significant difference in the classification of thrombi extracted, TIMI flow grade, cTFC, CK-MB,NT-proBNP and LVEF between group C and D, but group A was better than group B. Analysis of variance showed that the optimal number of suction was 4-5 times.

Conclusions

Optimized thrombus aspiration can significantly improve myocardial perfusion and short-term and medium-term prognosis of STEMI patients after PCI, and reduce the incidence of slow flow and no-reflow. The optimal suction times were 4-5 times. Traditional aspiration method with more aspiration times is harmful to cardiac prognosis. Thrombus aspiration does not increase the incidence of stroke events and is safe.Clinical Trial Registration: identifier, ChiCTR2300073410.

Subacute right coronary artery thrombosis treated by using Excimer Laser Coronary Angioplasty: a case report

Background

Managing high thrombotic burden in the context of myocardial infarction remains a challenging scenario.

Case summary

A 51-year-old male was admitted for a subacute inferior myocardial infarction with persistent chest pain. Emergent coronary angiography showed an ostial-proximal thrombotic occlusion of a large ectatic right coronary artery. Several balloon inflations were performed that were not able to improve distal TIMI flow beyond II. With the intent of vaporizing the remaining thrombus, Excimer Laser Coronary Angioplasty was performed with a favourable outcome.

Discussion

The present case constitutes an opportunity to revisit percutaneous and non-percutaneous strategies to tackle persistent coronary thrombus showing a contemporary approach to niche technologies such as laser angioplasty.

Rationale and Design of a Randomized Controlled Pilot Trial to Assess Stent Retriever Thrombectomy for Thrombus Burden Reduction in Patients with Acute Myocardial Infarction: The RETRIEVE-AMI Study

BACKGROUND

ST-elevation myocardial infarction (STEMI) is typically caused by thrombotic occlusion of a coronary artery with subsequent hypoperfusion and myocardial necrosis. In approximately half of patients with STEMI, despite successful restoration of epicardial coronary patency, downstream myocardium perfusion remains impeded. Coronary microvascular injury is one of the key mechanisms behind suboptimal myocardial perfusion and it is primarily, yet not exclusively, related to distal embolization of atherothrombotic material following recanalization of the culprit artery. Routine manual thrombus-aspiration has failed to show clinical efficacy in this scenario. This could be related with limitations in technology adopted as well as patients' selection. To this end, we set out to explore the efficacy and safety of stent retriever-assisted thrombectomy based on clot-removal device routinely used in stroke intervention.

STUDY DESIGN AND OBJECTIVES

The stent RETRIEVEr thrombectomy for thrombus burden reduction in patients with Acute Myocardial Infarction (RETRIEVE-AMI) study has been designed to establish whether stent retriever-based thrombectomy is safe and more efficacious in thrombus modification than the current standard of care: manual thrombus aspiration or stenting. The RETRIEVE-AMI trial will enrol 81 participants admitted for primary PCI for inferior STEMI. Participants will be 1:1:1 randomised to receive either standalone PCI, thrombus aspiration and PCI, or retriever-based thrombectomy and PCI. Change in thrombus burden will be assessed via optical coherence tomography imaging. A telephone follow-up at 6 months will be arranged.

CONCLUSIONS

It is anticipated by the investigators that stent retriever thrombectomy will more effectively reduce the thrombotic burden compared to current standard of care whilst being clinically safe.

In Vitro Comparison of Several Thrombus Removal Tools

BACKGROUND

Although the routine use of thrombus aspiration is not recommended, the thrombectomy technique still might be considered for a selected population of patients. Therefore, the assessment of the effectiveness of commercially available thrombectomy devices is still clinically relevant.

AIM

Here, we present an in vitro comparison of several different types of catheters that can be used for thrombus aspiration or removal.

METHODS

Through the removal of 6 h and 24 h human blood clots in an in vitro model, four catheters were compared: the Launcher, Pronto V4, Vasco+ and the stent-retriever Catchview. The aspiration efficacy was expressed as a percentage of the initial thrombus weight. The effectiveness of the patient's aspiration was dependent on the time of thrombus formation and was significantly higher for a thrombus formed over 24 h (58.5 ± 26.5%) than for one formed over 6 h (48.0 ± 22.5%; p < 0.001). In the presented in vitro model, Pronto V4 and Launcher showed the highest efficiency.

CONCLUSIONS

Large-bore aspiration catheters were found to be more effective than narrow-bore catheters or stent-retrievers in an in vitro model of thrombus removal. The thrombus aspiration efficacy increases with longer thrombus formation times.

Machine learning assisted reflectance spectral characterisation of coronary thrombi correlates with microvascular injury in patients with ST-segment elevation acute coronary syndrome

Aims

We set out to further develop reflectance spectroscopy for the characterisation and quantification of coronary thrombi. Additionally, we explore the potential of our approach for use as a risk stratification tool by exploring the relation of reflectance spectra to indices of coronary microvascular injury.

Methods and results

We performed hyperspectral imaging of coronary thrombi aspirated from 306 patients presenting with ST-segment elevation acute coronary syndrome (STEACS). Spatially resolved reflected light spectra were analysed using unsupervised machine learning approaches. Invasive [index of coronary microvascular resistance (IMR)] and non-invasive [microvascular obstruction (MVO) at cardiac magnetic resonance imaging] indices of coronary microvascular injury were measured in a sub-cohort of 36 patients. The derived spectral signatures of coronary thrombi were correlated with both invasive and non-invasive indices of coronary microvascular injury. Successful machine-learning-based classification of the various thrombus image components, including differentiation between blood and thrombus, was achieved when classifying the pixel spectra into 11 groups. Fitting of the spectra to basis spectra recorded for separated blood components confirmed excellent correlation with visually inspected thrombi. In the 36 patients who underwent successful thrombectomy, spectral signatures were found to correlate well with the index of microcirculatory resistance and microvascular obstruction; R²: 0.80, p < 0.0001, n = 21 and R²: 0.64, p = 0.02, n = 17, respectively.

Conclusion

Machine learning assisted reflectance spectral analysis can provide a measure of thrombus composition and evaluate coronary microvascular injury in patients with STEACS. Future work will further validate its deployment as a point-of-care diagnostic and risk stratification tool for STEACS care.

Successful visible thrombus aspiration in ST-segment elevation myocardial infarction: associated factors and the clinical impact

BACKGROUND

Thrombus aspiration (TA) has been considered a procedure for controlling distal emboli and improving microvascular perfusion. However, current guidelines classify routine TA as class III recommendation, and it has been reported that the efficacy of TA is limited because of the relatively high incidence of failure in retrieval of thrombotic material. The aim of this study was to explore patient characteristics and procedural factors associated with successful TA in ST-elevation myocardial infarction (STEMI) and to assess the clinical impact of successful TA.

METHODS

This single-center retrospective study enrolled 158 STEMI patients who underwent TA as initial recanalization. Factors associated with successful TA, which was defined as retrieving any visible material by aspiration catheter, were explored, and angiographical and short-term outcomes were assessed.

RESULTS

In 146 cases (92.4%), the aspiration catheter reached the culprit lesion. Successful TA was achieved in 72 cases (45.6%). The single angiographical characteristic of successful TA was a higher Thrombolysis in Myocardial Infarction grade before TA. Among the procedural characteristics, the rate of successful TA was higher with a 7-French aspiration catheter compared with the rate with a 6-French catheter (57.1% vs. 29.9%, P  = 0.01). Thrombolysis in Myocardial Infarction grade 3 flow was more frequent in patients with successful TA immediately after TA (36.1% vs. 16.3%, P  = 0.006) and at final angiography (91.7% vs 79.1%, P  = 0.04) compared with the grade in patients without successful TA, respectively.

CONCLUSIONS

The use of a larger aspiration catheter may be effective in retrieving visible thrombus material, and successful TA led to better angiographical results.

Neuropeptide-Y Levels in ST-Segment-Elevation Myocardial Infarction: Relationship With Coronary Microvascular Function, Heart Failure, and Mortality

Background

The sympathetic cotransmitter, neuropeptide Y (NPY), is released into the coronary sinus during ST‐segment–elevation myocardial infarction and can constrict the coronary microvasculature. We sought to establish whether peripheral venous (PV) NPY levels, which are easy to obtain and measure, are associated with microvascular obstruction, myocardial recovery, and prognosis.

Methods and Results

NPY levels were measured immediately after primary percutaneous coronary intervention and compared with angiographic and cardiovascular magnetic resonance indexes of microvascular function. Patients were prospectively followed up for 6.4 (interquartile range, 4.1–8.0) years. PV (n=163) and coronary sinus (n=68) NPY levels were significantly correlated (r=0.92; P<0.001) and associated with multiple coronary and imaging parameters of microvascular function and infarct size (such as coronary flow reserve, acute myocardial edema, left ventricular ejection fraction, and late gadolinium enhancement 6 months later). We therefore assessed the prognostic value of PV NPY during follow‐up, where 34 patients (20.7%) developed heart failure or died. Kaplan‐Meier survival analysis demonstrated that high PV NPY levels (>21.4 pg/mL by binary recursive partitioning) were associated with increased incidence of heart failure and mortality (hazard ratio, 3.49 [95% CI, 1.65–7.4]; P<0.001). This relationship was maintained after adjustment for age, cardiovascular risk factors, and previous myocardial infarction.

Conclusions

Both PV and coronary sinus NPY levels correlate with microvascular function and infarct size after ST‐segment–elevation myocardial infarction. PV NPY levels are associated with the subsequent development of heart failure or mortality and may therefore be a useful prognostic marker. Further research is required to validate these findings.

Prognostic Role of Residual Thrombus Burden Following Thrombectomy: Insights From the TOTAL Trial

BACKGROUND

It is unclear whether more effective forms of thrombus removal than current aspiration catheters would lead to improved outcomes. We sought to evaluate the prognostic role of residual thrombus burden (rTB), after manual thrombectomy, in patients undergoing primary percutaneous coronary intervention with routine manual thrombectomy in the TOTAL trial (Thrombectomy Versus PCI Alone).

METHODS

This is a single-arm analysis of patients from the TOTAL trial who underwent routine manual aspiration thrombectomy. The rTB was quantified by an angiographic core laboratory using the Thrombolysis in Myocardial Infarction criteria and validated using existing optical coherent tomography data. Large rTB was defined as grade ≥3. The primary outcome was death from cardiovascular causes, recurrent myocardial infarction, cardiogenic shock, or new or worsening heart failure within 180 days.

RESULTS

Of 5033 patients randomized to routine thrombectomy, 2869 patients had quantifiable rTB (1014 [35%] had large rTB). Patients with large rTB were more likely to have hypertension, previous percutaneous coronary intervention, myocardial infarction, or Killip class III on presentation but less likely to have Killip class I. The primary outcome occurred more frequently in patients with large rTB, even after adjustment for known risk predictors (8.6% versus 4.6%; adjusted hazard ratio, 1.83 [95% CI, 1.34-2.48]). These patients also had a higher risk of cardiovascular death (adjusted hazard ratio, 1.83 [95% CI, 1.13-2.95]), cardiogenic shock (adjusted hazard ratio, 2.02 [95% CI, 1.08-3.76]), and heart failure (adjusted hazard ratio, 1.74 [95% CI, 1.02-2.96]) but not myocardial infarction or stroke.

CONCLUSIONS

Large rTB is a common finding in primary percutaneous coronary intervention and is associated with increased risk of adverse cardiovascular outcomes, including cardiovascular death. Future technologies offering better thrombus removal than current devices may decrease or even eliminate the risk associated with rTB. This, potentially, can turn into a strategic option to be studied in clinical trials.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01149044.

Impact of residual thrombus burden on ventricular deformation after acute myocardial infarction: A sub-analysis from an intravascular optical coherence tomography study

BACKGROUND

Coronary residual thrombus before stenting in ST-segment elevation myocardial infarction (STEMI) has been linked to microvascular injury but its impact on ventricular deformation and cardiac dysfunction in longer term remains unclear.

METHODS

This was a post-hoc sub-analysis from an optical coherence tomography registry. Residual thrombus before stenting was measured geometrically and maximal thrombus-to-lumen area ratio (MTR) was reported. Cardiovascular magnetic resonance (CMR) follow-ups were performed at 30 days post STEMI. The primary outcomes were CMR-derived parameters including left ventricular ejection fraction (LVEF), infarct size, microvascular obstruction (MVO), and left ventricular global strains in radial (GRS), circumferential (GCS), longitudinal (GLS) directions.

FINDINGS

From March 2017 to March 2019, forty-two patients with first-ever anterior STEMI were included. Average CMR follow-up time was 33 (IQR 30-37) days. In multivariable analysis, MTR was significantly associated with LVEF (per 10%, adjusted β = -1·96, 95%CI -3·66 to -0·26), MVO (per 10%, adjusted β = 0·07, 95%CI 0·01 to 0·13), GRS (per 10%, adjusted β = -1·26, 95%CI -2·28 to -0·23), and GCS (per 10%, adjusted β = 0·53, 95%CI 0·01 to 1·06). However, it was not related to GLS (per 10%, adjusted β = 0·29, 95%CI -0·85 to 1·43) or infarct size (per 10%, adjusted β = 0·07, 95%CI -0·40 to 0·55).

INTERPRETATION

Larger residual thrombus burden was associated with worse GRS and GCS but not GLS after a first anterior myocardial infarction.

FUNDING

This work was supported by Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (2016-I2M-1-009), National Natural Science Foundation of China (81,970,308, 81,930,044, and 81,620,108,015), Sanming Project of Medicine in Shenzhen (SZSM201911017), and Shenzhen Key Medical Discipline Construction Fund (No. SZXK001).

Micro-CT for Biological and Biomedical Studies: A Comparison of Imaging Techniques

Several imaging techniques are used in biological and biomedical studies. Micro-computed tomography (micro-CT) is a non-destructive imaging technique that allows the rapid digitisation of internal and external structures of a sample in three dimensions and with great resolution. In this review, the strengths and weaknesses of some common imaging techniques applied in biological and biomedical fields, such as optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy, are presented and compared with the micro-CT technique through five use cases. Finally, the ability of micro-CT to create non-destructively 3D anatomical and morphological data in sub-micron resolution and the necessity to develop complementary methods with other imaging techniques, in order to overcome limitations caused by each technique, is emphasised.

Laser Vaporization of Intracoronary Thrombus and Identifying Plaque Morphology in ST-Segment Elevation Myocardial Infarction as Assessed by Optical Coherence Tomography

Objectives

We evaluated the thrombus-vaporizing effect of excimer laser coronary angioplasty (ELCA) in patients with ST-segment elevation myocardial infarction (STEMI) by optical coherence tomography (OCT).

Background

Larger intracoronary thrombus elevates the risk of interventional treatment and mortality in patients with STEMI.

Methods

A total of 92 patients with STEMI who presented within 24 hours from the onset and underwent ELCA following manual aspiration thrombectomy (MT) were analyzed.

Results

The mean baseline thrombolysis in myocardial infarction flow grade was 0.4 ± 0.6, which subsequently improved to 2.3 ± 0.7 after MT (p < 0.0001) and 2.7 ± 0.5 after ELCA (p=0.0001). The median residual thrombus volume after MT was 65.7 mm³, which significantly reduced to 47.5 mm³ after ELCA (p < 0.0001). Plaque rupture was identified by OCT in only 22 cases (23.9%) after MT, but was distinguishable in 36 additional cases after ELCA (total: 58 cases; 63.0%). Ruptured lesions contained a higher proportion of red thrombus than nonruptured lesions (75.9% vs. 43.3%, p=0.001). Significantly larger thrombus burden after MT (69.6 mm³ vs. 56.3 mm³, p < 0.05) and greater thrombus reduction by ELCA (21.2 mm³ vs. 11.8 mm³, p < 0.01) were observed in ruptured lesions than nonruptured lesions.

Conclusions

ELCA effectively vaporized intracoronary thrombus in patients with STEMI even after MT. Lesions with plaque rupture contained larger thrombus burden that was frequently characterized by red thrombus and more effectively reduced by ELCA.

Myocardial salvage after ST-segment-elevation myocardial infarction: comparison between prasugrel and clopidogrel in the presence or absence of high-residual platelet reactivity

BACKGROUND

The effect of prasugrel over clopidogrel on myocardial salvage in ST-segment-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (p-PCI) is not fully elucidated.

METHODS

Among 854 consecutive STEMI patients who underwent p-PCI, 446 patients were evaluated by two-phase (7 days and 3 months) single-photo emission computed tomography (SPECT). Patients were divided into two groups based on the loading P2Y12 inhibitor. The clopidogrel group was further divided based on the result of platelet function testing. Thus, the prasugrel group included 227 patients; the clopidogrel without high-residual platelet reactivity (HRPR) group, 109 patients; and the clopidogrel with HRPR group, 107 patients. The primary endpoint was the Myocardial Salvage Index (MSI), determined by SPECT.

RESULTS

The incidence of final TIMI 0/1 and TIMI myocardial perfusion grade 0/1 was higher in the clopidogrel with HRPR group (0.9%, 1.8%, and 7.5%, P =  .002; 19.8%, 29.4%, and 41.1%, P = .0002, in the prasugrel, clopidogrel without HRPR, and clopidogrel with HRPR groups, respectively). The MSI was significantly lower in the clopidogrel with HRPR group (48% [27-66], 44% [30-72], and 36% [15-55], P =  .006, respectively).

CONCLUSIONS

Prasugrel in STEMI patients was associated with an increased MSI compared with clopidogrel in the presence of HRPR.

Aspiration Thrombectomy

Distal embolization of thrombus can lead to impairment of microvascular perfusion, and measures of abnormal microvascular perfusion have been associated with increased mortality and worsened clinical outcomes. Large multicenter randomized controlled trials and multiple meta-analyses have failed to demonstrate an improvement in clinical outcomes with the routine use of manual aspiration thrombectomy, with some studies suggesting an increased incidence of stroke, likely owing to thrombus dislodgement during retrieval leading to cerebral vessel embolization. In patients with high thrombus burden who do not respond to balloon predilation, the use of manual aspiration thrombectomy as a bailout treatment strategy can be considered.

Micro-CT-Based Quantification of Extracted Thrombus Burden Characteristics and Association With Angiographic Outcomes in Patients With ST-Elevation Myocardial Infarction: The QUEST-STEMI Study

Background: Angiographic detection of thrombus in STEMI is associated with adverse outcomes. However, routine thrombus aspiration failed to demonstrate the anticipated benefit. Hence, management of high coronary thrombus burden remains challenging. We sought to assess for the first time extracted thrombotic material characteristics utilizing micro-computed tomography (micro-CT). Methods: One hundred thirteen STEMI patients undergoing thrombus aspiration were enrolled. Micro-CT was undertaken to quantify retrieved thrombus volume, surface, and density. Correlation of these indices with angiographic and electrocardiographic outcomes was performed. Results: Mean aspirated thrombus volume, surface, and density (±standard deviation) were 15.71 ± 20.10 mm³, 302.89 ± 692.54 mm², and 3139.04 ± 901.88 Hounsfield units, respectively. Aspirated volume and surface were significantly higher (p < 0.001) in patients with higher angiographic thrombus burden. After multivariable analysis, independent predictors for thrombus volume were reference vessel diameter (RVD) (p = 0.011), right coronary artery (RCA) (p = 0.039), and smoking (p = 0.027), whereas RVD (p = 0.018) and RCA (p = 0.019) were predictive for thrombus surface. Thrombus volume and surface were independently associated with distal embolization (p = 0.007 and p = 0.028, respectively), no-reflow phenomenon (p = 0.002 and p = 0.006, respectively), and angiographically evident residual thrombus (p = 0.007 and p = 0.002, respectively). Higher thrombus density was correlated with worse pre-procedural TIMI flow (p < 0.001). Patients with higher aspirated volume and surface developed less ST resolution (p = 0.042 and p = 0.023, respectively). Conclusions: Angiographic outcomes linked with worse prognosis were more frequent among patients with larger extracted thrombus. Despite retrieving larger thrombus load in these patients, current thrombectomy devices fail to deal with thrombotic material adequately. Further studies of novel thrombus aspiration technologies are warranted to improve patient outcomes. Clinical Trial Registration: QUEST-STEMI trial ClinicalTrials.gov number: NCT03429608 Date of registration: February 12, 2018. The study was prospectively registered.

Aspiration thrombectomy in ST-Elevation myocardial infarction: Further insights from a network meta-analysis of randomized trials

Background

The initial enthusiasm for thrombectomy during percutaneous coronary intervention (PCI) of ST-elevation myocardial infarction (STEMI) patients has given way to restraint. There has been some limited interest whether it is beneficial in a few selected subgroups. Hence, we performed a network meta-analysis to compare conventional PCI (cPCI), Aspiration or manual thrombectomy (AT) and Mechanical thrombectomy (McT) for clarification.

Methods

Electronic databases were searched for randomized studies that compared AT, McT, or cPCI. A network meta-analysis was performed and odd’s ratio (OR) with 95% confidence intervals was generated for major adverse cardiac events (MACE), mortality, myocardial infarction (MI), target vessel revascularization (TVR), stent thrombosis (ST), stroke, left ventricular ejection fraction (LVEF), myocardial blush grade (MBG) and ST segment resolution (STR).

Results

A total of 43 randomized trials (n = 26,682) were included. The risk of MACE (OR 0.86 95% CI 0.73–1.00), Mortality (OR 0.85 95% CI 0.73–0.99), MI (OR 0.65, 95% CI: 0.44–0.95) and TVR (OR 0.86, 95% CI: 0.74–1.00) were lower with AT compared to cPCI. The risk of ST and stroke was no different with the use of adjunctive AT. MBG, STR, and LVEF improved with the use of AT while the infarct size was no different in the two groups.

Conclusions

Our comprehensive network meta-analysis suggests conflicting outcomes with AT. While Mortality, MACE, MI seem better, there is a suggestion that, Stroke and ST might be worse. Whether AT can still be pursued in any select cases should be further scrutinized.

Aspiration Thrombectomy for Acute ST-Elevation Myocardial Infarction: Literature Review

Over the years, aspiration thrombectomy for management of acute coronary syndrome was the center of discussion however due to multiple randomized control trials which did not provide sufficient evidence supporting use of this approach, this method is not routinely used. The benefit of this approach remains unknown, however, it is important to acknowledge the evolution of aspiration catheters and their potential in minimizing complications which were previously the set back of this approach. We provide a comprehensive review of the previous trials and how those catheters have since evolved significantly.

Residual atherothrombotic burden after primary percutaneous coronary intervention and myocardial reperfusion-An optical frequency domain imaging study

OBJECTIVES

We aimed to assess the relationship between residual in-stent atherothrombotic burden (ATB) after primary percutaneous coronary intervention (PCI) measured by optical frequency domain imaging (OFDI) using different measurement methods and myocardial blush grade (MBG).

BACKGROUND

The impact of residual ATB after primary PCI on myocardial reperfusion remains unclear.

METHODS

We prospectively included 60 ST-elevation myocardial infarction patients pretreated with aspirin and ticagrelor. OFDI volumetric quantification using planimetry (with intervals every frame or every millimeter) and semiquantitative score were used to determine ATB. Patients were divided into two groups according to final MBG 3 or <3.

RESULTS

The mean ATB was 10.08 ± 5.21%. ATB was lower in patients with final MBG 3 compared to those with impaired MBG, regardless of the measurement method (8.15 ± 5.58 vs. 11.77 ± 4.28%; p = .007 for quantification per frame; 7.8 ± 5.19 vs. 11.07 ± 4.07%; p = .009 for quantification per mm and 11.21 ± 11.75 vs. 22.91 ± 17.35; p = .003 for the semiquantitative thrombus score, respectively).

CONCLUSION

Residual post-stenting ATB remains substantial after primary PCI in STEMI patients, even when pretreated with ticagrelor and aspirin. ATB appears as a significant correlate of suboptimal myocardial reperfusion, a known surrogate of clinical outcome.

To Whom Thrombus Aspiration May Concern?

BACKGROUND

Thrombus aspiration for ST-segment elevation myocardial infarction (STEMI) may improve myocardial perfusion. However, these favourable results called into a question by data indicating not only a lack of efficacy but a risk of potentially deleterious complications.

AIM

To assess the effect of thrombus aspiration during the primary percutaneous coronary intervention (PPCI) on procedural angiographic results, stent characteristics, and major adverse cardiac and cerebrovascular events (MACCE).

METHODS

All consecutive STEMI patients candidate for PPCI and admitted to Critical Care Department, Cairo University hospitals, managed either by thrombectomy before primary PCI (if thrombus score ≥ 3) or conventional PPCI, Six hundred seven subjects were enrolled in the study divided into Group with thrombectomy before PPCI (107 subjects, 18%), and group with Conventional PCI (500 subjects, 82%). ST-segment resolution, peak CK-MB, TIMI score, thrombus score, and MBG were assessed; stent number, diameter, length and stented segment were reported and follow up MACCE was reported (in hospital and 1-year post-intervention).

RESULTS

Mean values for peak CKMB were less in thrombectomy group (228 ± 174 I/U vs 269 ± 186 I/U, p = 0.04), ST segment resolution ≥ 70% occurred in {63 subjects (58.9%) vs 233 (46.6%), p = 0.001} in thrombectomy vs conventional group respectively. TIMI score pre procedure was zero in (102 subjects (95%) vs 402 (80.4%), p = 0.001), while TIMI III post procedure was reported in (100 subjects (93.4%) vs 437 (87%), p = 0.06), MBG mean values were (2.4 ± 0.6 vs 2.0 ± 1, p = 0.001), thrombus score was higher in thrombectomy group (4.6 ± 0.4 vs 0.8 ± 1.7, p = 0.001) in thrombectomy vs conventional group respectively. Direct stenting was { 34 patients (31%) vs 102 patients (20%), p = 0.05}, mean stent diameter (2.7 ± 1.3 mm vs 3.5 ± 1.3 mm, p = 0.3), mean stent length was (19.9 mm ± 10 versus 22.7 mm ± 8 in p 0.01). mean stent number was (1.0 ± 0.5 vs 1.2 ± 0.6, p = 0.001), mean stented segment was (22.5 ± 13.5 vs 28.5 ± 15.2 mm, p = 0.001) in thrombectomy vs conventional group respectively. MACCE in hospital were reported in {9 subjects (8.4%) vs 70 (14%), p = 0.07)}. Follow up MACCE after 1 year reported in {6 subjects (5.6 %) vs 80 (16 %), p 0.= 4} in thrombectomy vs conventional group respectively.

CONCLUSION

Thrombus aspiration before primary PCI (in a selected group with thrombus score ≥ 3) improves myocardial perfusion, suggested by better ST-segment resolution, TIMI flow, less peak CKMB and MBG, associated with a higher rate of direct stenting, shorter stent length, stented segments and less number of stents. Although thrombus aspiration was done in more risky patients (higher thrombus score) MACCE (in hospital and 1 year follow up) showed no statistical difference.

Intracoronary Optical Coherence Tomography 2018: Current Status and Future Directions

The advent of intravascular imaging has been a significant advancement in visualization of coronary arteries, particularly with optical coherence tomography (OCT) that allows for high-resolution imaging of intraluminal and transmural coronary structures. Accumulating data support a clinical role for OCT in a multitude of clinical scenarios, including assessing the natural history of atherosclerosis and modulating effects of therapies, mechanisms of acute coronary syndromes, mechanistic insights into the effects of novel interventional devices, and optimization of percutaneous coronary intervention. In this state-of-the-art review, we provide an overview of the published data on the clinical utility of OCT, highlighting the areas that need further investigation and the current barriers for further adoption of OCT in interventional cardiology practice.

Comparison of visual assessment and computer image analysis of intracoronary thrombus type by optical coherence tomography

Background

Analysis of intracoronary thrombus type by optical coherence tomography (OCT) imaging is highly subjective. We aimed to compare a newly developed image analysis method to subjective visual classification of thrombus type identified by OCT.

Methods

Thirty patients with acute ST elevation myocardial infarction were included. Thrombus type visually classified by two independent readers was compared with analysis using QCU-CMS software.

Results

Repeatability of the computer-based measurements was good. By using a ROC, area under curve values for discrimination of white and red thrombi were 0.92 (95% confidence intervals (CI) 0.83–1.00) for median attenuation, 0.96 (95% CI 0.89–1.00) for mean backscatter and 0.96 (95% CI 0.89–1.00) for mean grayscale intensity. Median attenuation of 0.57 mm^-1 (sensitivity 100%, specificity 71%), mean backscatter of 5.35 (sensitivity 92%, specificity 94%) and mean grayscale intensity of 120.1 (sensitivity 85%, specificity 100%) were identified as the best cut-off values to differentiate between red and white thrombi.

Conclusions

Attenuation, backscatter and grayscale intensity of thrombi in OCT images differentiated red and white thrombi with high sensitivity and specificity. Measurement of these continuous parameters can be used as a less user-dependent method to characterize in vivo thrombi. The clinical significance of these findings needs to be tested in further studies.

Plaque erosion versus rupture characterization by optical frequency domain imaging before and after coronary stenting following successful fibrinolysis for ST-segment elevation myocardial infarction

Intracoronary thrombus burden affects the quality of myocardial reperfusion in the setting of ST-elevation myocardial infarction (STEMI). We aimed to study the characteristics of the plaque and thrombus assessed by intracoronary optical frequency domain imaging (OFDI) according to the presence of plaque rupture or erosion in STEMI patients treated with successful fibrinolysis. Pre-stenting thrombus and post-stenting atherothrombotic burden were compared between plaque rupture and erosion. Twenty-seven consecutive patients were included: 17 (63%) had OFDI-plaque rupture and 10 (37%) had OFDI-erosion. Thrombus volume and burden were significantly higher in case of rupture compared to erosion at baseline (13.4 ± 18.4 vs 2.8 ± 2.3 mm³; p = 0.03 and 33.8 ± 17.5 vs 17.5 ± 9.9%; p = 0.007, respectively). In the rupture group, the core of the thrombus consisted dominantly of red thrombus evenly distributed along the entire culprit plaque. In the erosion group, it consisted dominantly of white thrombus with a focal distribution near the minimal lumen area zone. After stenting, the atherothrombotic volume, burden and its distribution, as well as angiographic estimators of myocardial reperfusion were similar between groups. Our study showed that pre-PCI thrombus amount, typesetting and distribution are mainly linked to the underlying mechanism of STEMI. After stenting, the atherothrombotic burden and its distribution were similar between the groups.

Thrombus Aspiration for ST-Segment-Elevation Myocardial Infarction in Modern Era: Still an Issue of Debate?

The role of manual thrombus aspiration (TA) during primary percutaneous coronary intervention (PPCI) for acute ST-segment-elevation myocardial infarction has been a matter of intense research and debate now. Although recent randomized controlled clinical trials (notably TASTE [Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia] and TOTAL [Trial of Routine Aspiration Thrombectomy With PCI Versus PCI Alone in Patients With STEMI]) do not supply evidence supporting the routine use of TA in patients with ST-segment-elevation myocardial infarction, manual TA remains a therapeutic option for interventional cardiologists when treating patients with substantial thrombus burden during PPCI. It remains unknown whether patients might actually benefit from TA applied in a more selective manner depending on the thrombus burden during PPCI, instead of routine application. In this review, we summarize current knowledge on the instruments used in the TA procedure, positive as well as negative clinical effects of TA during PPCI, and analyze the potential reasons for observed effects, in an effort to help the clinical decision making by physicians for the use of TA in individual ST-segment-elevation myocardial infarction patients during PPCI.

Potent effect of prasugrel on acute phase resolution of intra-stent athero-thrombotic burden after percutaneous intervention to acute coronary syndrome

BACKGROUND

Recent studies suggested protruding thrombus and atheroma after stent placement could be a substrate for subsequent adverse ischemic events. Although protruded atherothrombotic burden can be assessed as intra-stent tissue (IST) by optical coherence tomography (OCT), the effects of potent antiplatelet therapy on the acute phase resolution of IST in patients with acute coronary syndrome (ACS) was unknown.

METHODS

Ninety-six consecutive ACS patients with multi-vessel disease were enrolled in this prospective registry. In combination with aspirin, either clopidogrel or prasugrel was selected according to the date of enrolment. OCT examination was done immediately after percutaneous coronary intervention (post-PCI) and 10 days after index PCI (follow-up acute phase) to calculate averaged IST score as semi-quantitative measures of IST. High residual platelet reactivity (HRPR) was defined as platelet reactivity units (PRU)≥240 by VerifyNow P2Y12 assay (Accumetrics Inc., San Diego, CA, USA).

RESULTS

Thirty two patients (38 stents) were enrolled in the prasugrel group and sixty four patients (72 stents) in the clopidogrel group. Averaged IST scores post-PCI were similar between the two groups (0.68±0.41 vs. 0.68±0.40, p=0.99), which decreased in all of the prasugrel group and in 87.5% of the clopidogrel group (p=0.02). Consequently, changes in averaged IST score (delta averaged IST score) were significantly greater in the prasugrel group compared to those in the clopidogrel group (-0.411±0.288 vs. -0.299±0.270, p=0.045). The frequency of HRPR was significantly lower in the prasugrel group (10.0% vs 32.4%, p=0.028).

CONCLUSIONS

Prasugrel plus aspirin achieved greater acute phase reduction of IST than clopidogrel plus aspirin, which might underlie the clinical benefit of potent antiplatelet therapy in ACS. (UMIN000018751).

[Deferred versus immediate stenting in patients with ST - segment elevation myocardial infarction and residual large thrombus burden reclassified in the culprit lesion]

BACKGROUND

Reclassification of a large thrombus burden is an independent predictor of major adverse cardiac events and no-reflow in patients with ST- segment elevation myocardial infarction (STEMI). Patients with a greater residual thrombus burden have worse microvascular dysfunction and greater myocardial damage.

METHODS

A retrospective analysis was performed on 833 STEMI patients who underwent primary percutaneous coronary intervention. The final residual thrombus burden was reclassified after the lesion was wired, and a thrombus aspiration or balloon dilatation was performed to restore and stabilise a thrombolysis in myocardial infarction (TIMI) 2-3 flow. Deferred stenting (DEI) was compared with immediate stenting (ISI) group, and the primary outcome was the incidence of no-/slow-reflow (TIMI ≤ 2, or TIMI 3 with myocardial blush grade < 2).

RESULTS

Overall, 47 patients (6.8%) had a residual large thrombus burden reclassified. The right coronary artery was the culprit vessel in 34 cases. More patients had coronary ectasia in the DSI group (P=.005). Fewer patients in the DSI had no-/slow-reflow (36% vs. 58%), and the myocardial blush grade 3 was more frequent in the DSI group (P=.005). After repeat coronary angiography in the DSI group, stenting was not performed in 56%, and oral anticoagulation was more frequent in the follow-up (P=.031). Major cardiac adverse events were similar between groups. There was a tendency to better left ventricular function in the DSI group (P=.056).

CONCLUSIONS

Deferred stenting may be an efficient option in STEMI patients with a residual large thrombus burden reclassified after achieving a stable TIMI 2-3 flow.

Effective anti-thrombotic therapy without stenting: intravascular optical coherence tomography-based management in plaque erosion (the EROSION study)

Aims

Plaque erosion, compared with plaque rupture, has distinctly different underlying pathology and therefore may merit tailored therapy. In this study, we aimed to assess whether patients with acute coronary syndrome (ACS) caused by plaque erosion might be stabilized by anti-thrombotic therapy without stent implantation.

Methods and results

This was a single-centre, uncontrolled, prospective, proof-of concept study. Patients with ACS including ST-segment elevation myocardial infarction were prospectively enrolled. If needed, aspiration thrombectomy was performed. Patients diagnosed with plaque erosion by optical coherence tomography (OCT) and residual diameter stenosis <70% on coronary angiogram were treated with anti-thrombotic therapy without stenting. OCT was repeated at 1 month and thrombus volume was measured. The primary endpoint was >50% reduction of thrombus volume at 1 month compared with baseline. The secondary endpoint was a composite of cardiac death, recurrent ischaemia requiring revascularization, stroke, and major bleeding. Among 405 ACS patients with analysable OCT images, plaque erosion was identified in 103 (25.4%) patients. Sixty patients enrolled and 55 patients completed the 1-month follow-up. Forty-seven patients (47/60, 78.3%; 95% confidence interval: 65.8-87.9%) met the primary endpoint, and 22 patients had no visible thrombus at 1 month. Thrombus volume decreased from 3.7 (1.3, 10.9) mm3 to 0.2 (0.0, 2.0) mm3. Minimal flow area increased from 1.7 (1.4, 2.4) mm2 to 2.1 (1.5, 3.8) mm2. One patient died of gastrointestinal bleeding, and another patient required repeat percutaneous coronary intervention. The rest of the patients remained asymptomatic.

Conclusion

For patients with ACS caused by plaque erosion, conservative treatment with anti-thrombotic therapy without stenting may be an option.

Cost assessment of treatment of acute myocardial infarction and angiographically visible coronary thrombus

AIM

Study was aimed to assess the real-world costs of manual thrombectomy (MT) in selected ST-segment elevation myocardial infarction patients with intracoronary thrombus (IT).

METHODS

Study group (IT+) comprised 51 patients with MT applied and control group (IT-) comprised 56 patients without IT who underwent angioplasty alone. Costs comprised hospital care and cost of disposable materials used during primary angioplasty.

RESULTS

Complex management of patients with IT is more expensive, though allows to achieve clinical outcomes comparable to low-risk ST-segment elevation myocardial infarction patients without IT.

CONCLUSION

A complex pharmaco-interventional strategy, with glycoprotein IIB/IIIA inhibitor and MT, though more expensive, may prove cost-effective.

A comparison of intracoronary treatment strategies for thrombus burden removal during primary percutaneous coronary intervention: a COCTAIL II substudy

BACKGROUND

Manual thrombus aspiration and local drug delivery of abciximab have been proposed as a strategy to reduce thrombus burden during percutaneous coronary intervention in patients with ST elevation myocardial infarction; however, the effectiveness of these approaches, is uncertain. In this COCTAIL II substudy, we compared the effect of these strategies on prestenting and poststenting thrombus burden assessed by optical coherence tomography.

PATIENTS AND METHODS

COCTAIL II trial enrolled patients with ST elevation myocardial infarction randomized to intralesion (IL, by the ClearWay catheter) versus intracoronary (IC, by the guide catheter) abciximab bolus with or without aspiration thrombectomy (AT). The following parameters were used to quantify atherothrombotic burden: thrombus volume (TVol), maximum thrombus area (TA), and thrombus burden (TB). Primary endpoint was the comparison of prestenting TVol after the use of local drug delivery (group IL+IL abciximab plus AT) versus nonlocal drug delivery (group IC abciximab plus AT+IC).

RESULTS

The final population consisted of 59 patients undergoing both prestenting and poststenting optical coherence tomography assessment. The amount of thrombus was not significantly different in the groups with local drug delivery of abciximab versus nonlocal drug delivery in both prestenting (TVol: 18.87±26.70 vs. 19.02±18.45; TB: 26.73±12.8 vs. 25.18±13.25; and maximum TA: 59.25±18.84 vs. 53.34±19.30) and poststenting (TVol: 8.46±9.15 vs. 8.05±6.81; TB: 6.68±3.54 vs. 6.24±3.66; and maximum TA: 15.47±7.61 vs. 16.52±11.55) evaluations. A good correlation between thrombus measurements after thrombus removal techniques and intrastent thrombus was observed.

CONCLUSION

Either local drug delivery of abciximab or manual thrombus aspiration showed comparable results in terms of prestenting and poststenting thrombus burden removal.

Synergistic ELCA-aspiration-DES thrombus removal strategy-embolus impact in high-risk plaque: A case report

RATIONALE

Thin-cap fibroatheroma (TCFA) and red thrombus are suggested as a high-risk of embolic complications during percutaneous coronary intervention (PCI). Intracoronary aspiration procedures occasionally result in either an insufficient thrombus removal or provide no significant effects on TCFA.

PATIENT CONCERNS

A 76-year-old male underwent coronary angiography for chest pain.

DIAGNOSES

Coronary angiography revealed a tight stenosis at the right coronary artery which resulted in treatment by PCI. Optical frequency domain imaging (OFDI) delineated a red thrombus with TCFA.

INTERVENTIONS

To avoid embolic complications, excimer laser coronary angioplasty (ELCA) was applied with intracoronary aspiration before drug-eluting stent (DES) implantation.

OUTCOMES

The red thrombus was vaporized by ELCA in an energy-intensity dependent manner and subsequently removed by intracoronary aspiration. The fibrous cap of TCFA was dissected with the material beneath the cap ablated by ELCA and extensively removed by intracoronary aspiration. DES implantation and postdilatation achieved an optimal result without flow compromise. This combined synergistic strategy of ELCA-aspiration-DES yielded a successful outcome.

LESSONS

A synergistic embolus removal strategy combining ELCA, aspiration and DES implantation is a promising option for the treatment of high-risk plaque with potential embolic complications.

Does Residual Thrombus After Aspiration Thrombectomy Affect the Outcome of Primary PCI in Patients With ST-Segment Elevation Myocardial Infarction?: An Optical Coherence Tomography Study

OBJECTIVES

The aim of this study was to evaluate if residual thrombus burden after aspiration thrombectomy affects the outcomes of primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Recent studies failed to show clinical benefit of aspiration thrombectomy in STEMI patients. This might be due to insufficient removal of thrombus at the culprit lesion.

METHODS

A total of 109 STEMI patients who underwent aspiration thrombectomy followed by stenting within 24 h from symptom onset were included. Optical coherence tomography was performed after thrombectomy to measure residual thrombus burden. Patients were divided into tertiles based on the amount of residual thrombus and the outcomes were compared.

RESULTS

Myocardial no reflow, defined as TIMI (Thrombolysis In Myocardial Infarction) flow grade of ≤2 and/or myocardial blush grade of ≤1 after stenting, was more observed frequently in patients in the highest tertile compared with those in the lowest tertile (44.4% vs. 16.7%; p = 0.001). Patients in the highest tertile also had greater myocardial damage measured by creatine kinase MB compared with those in the lowest tertile (p = 0.002).

CONCLUSIONS

STEMI patients with greater residual thrombus burden after aspiration thrombectomy had worse microvascular dysfunction and greater myocardial damage compared with those with smaller residual thrombus burden.

Culprit plaque morphology in STEMI - an optical coherence tomography study: insights from the TOTAL-OCT substudy

AIMS

Our aim was to compare stenosis severity and plaque content between STEMI culprit lesions with intact fibrous cap (IFC) and those with plaque rupture (PR) in a prospective study.

METHODS AND RESULTS

We evaluated 93 patients undergoing OCT and thrombectomy as part of a prospective substudy of the TOTAL (ThrOmbecTomy versus PCI ALone) trial. Culprit lesion morphology was assessable by OCT in 70/93 (75.3%). IFC was found in 31 (44.3%), PR in 34 (48.6%) and calcified nodule in five (7.1%) patients. Following thrombectomy, OCT demonstrated similar lumen area stenosis in IFC (79.3%) and PR (79.6%) (p=0.88). Lumen area stenosis <50% was observed in none of the patients with PR and in one patient with IFC. IFC had fewer quadrants with lipid plaque as compared to PR (28.16±15.02 vs. 39.12±14.23, p=0.004). However, in both lesion types, lipid was the predominant plaque type (83.9 vs. 63.7% of diseased quadrants).

CONCLUSIONS

In a prospective study of STEMI patients treated with thrombectomy, mild residual stenoses were uncommon in IFC lesions. Although lipid content was lower than in PR lesions, lipid composed the majority of the diseased segments in IFC.

The Role of Intracoronary Plaque Imaging with Intravascular Ultrasound, Optical Coherence Tomography, and Near-Infrared Spectroscopy in Patients with Coronary Artery Disease

The development of multiple diagnostic intracoronary imaging modalities has increased our understanding of coronary atherosclerotic disease. These imaging modalities, intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near-infrared spectroscopy (NIRS), have provided a method to study plaques and introduced the concept of plaque vulnerability. They are being increasingly used for percutaneous coronary intervention (PCI) optimization and are invaluable tools in research studying the pathophysiology of acute coronary syndrome (ACS), in-stent thrombosis and in-stent restenosis. IVUS has the ability to visualize the intracoronary lumen and the vessel wall and can be used to detect early atherosclerotic disease even in the setting of positive arterial remodeling. Studies supporting the use of IVUS to optimize stent deployment and apposition have shown a significant reduction in cardiovascular events. OCT provides even higher resolution imaging and near microscopic detail of plaques, restenoses, and thromboses; thus, it can identify the etiology of ACS. Ongoing trials are evaluating the role of OCT in PCI and using OCT to study stent endothelialization and neointimal proliferation. NIRS is a modality capable of localizing and quantifying lipid core burden. It is usually combined with IVUS and is used to characterize plaque composition. The benefits of NIRS in the setting of ACS have been limited to case reports and series. The utilization of all these intracoronary imaging modalities will continue to expand as their indications for clinical use and research grow. Studies to support their use for PCI optimization resulting in improved outcomes with potential to prevent downstream events are ongoing.

The role of residual intrastent thrombus during primary angioplasty: insights from the COCTAIL II study

AIMS

Recent frequency-domain optical coherence tomography studies showed that a complete removal of thrombotic materials is rarely achieved after percutaneous coronary interventions for ST segment elevation myocardial infarction. Residual intrastent thrombus can embolize distally leading to microcirculatory injury. The aim was to find a possible correlation between residual intrastent thrombus and angiographic indexes of myocardial reperfusion.

METHODS

The population consisted of 128 ST segment elevation myocardial infarction patients enrolled in the COCTAIL II trial. Intrastent thrombus at optical coherence tomography was defined as the maximum percentage value of thrombus area (thrombus area/stent area × 100 in the cross-section with largest thrombus). A thrombus area of at least 16% (mean value) was considered indicative of high residual intrastent thrombus. The following angiographic indexes of myocardial reperfusion were evaluated: thrombolysis in myocardial infarction (TIMI) value, corrected TIMI frame count and myocardial blush grade.

RESULTS

Angiographic and optical coherence tomography results are available in 119 patients: 64 had a maximum percentage value of thrombus area less than 16%, whereas the remaining 55 had a residual intrastent thrombus at least 16%. No differences were found regarding the microcirculatory indexes at baseline angiogram. After intervention, patients with intrastent thrombus less than 16% showed a significant improvement in the final TIMI value (2.87 ± 0.33 vs 2.67 ± 0.54; P = 0.014), final TIMI frame count (11.71 ± 4.58 vs 18.04 ± 17.32; P = 0.012) and a nonsignificant improvement in the final myocardial blush grade value (2.58 ± 0.58 vs 2.43 ± 0.76; P = 0.255).

CONCLUSION

Data obtained from this ancillary study of the COCTAIL II suggest that the presence of high residual intrastent thrombus in patients undergoing primary angioplasty is associated with worsened final microcirculatory indexes.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention in ST-Segment-Elevation Myocardial Infarction: A Prospective Propensity-Matched Cohort of the Thrombectomy Versus Percutaneous Coronary Intervention Alone Trial

BACKGROUND

Patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction are at increased risk for adverse events. It is unclear if image guidance by optical coherence tomography (OCT) can improve outcomes in these patients. We compared OCT-guided versus angiography-guided primary PCI for ST-segment-elevation myocardial infarction among patients in the Thrombectomy Versus PCI Alone (TOTAL) trial.

METHODS AND RESULTS

Among 10 732 patients enrolled in the TOTAL trial, OCT was used for PCI guidance as a part of a prospective substudy in 214 patients. Using 2:1 propensity matching, we identified 428 patients in the trial who had PCI performed with angiography guidance alone. The primary outcome was a composite of cardiovascular death, myocardial infarction, stent thrombosis, and target-vessel revascularization at 1 year. Secondary outcomes included final in-stent angiographic minimum lumen diameter, procedure time, and contrast dose. The final in-stent angiographic minimum lumen diameter was 2.99±0.48 mm in the OCT-guided group versus 2.79±0.47 mm in the angiography-guided group (P<0.0001). OCT- and angiography-guided PCI had a median (interquartile range) procedure time of 58 (47, 71) minute versus 38 (28, 52) minute (P<0.0001) and total contrast dose of 239.7±81.1 mL versus 193.3±78.6 mL (P<0.0001). The primary outcome was observed in 7.5% of the OCT-guided group versus 9.8% of the angiography-guided group (hazard ratio, 0.76; 95% confidence interval, 0.43-1.34; P=0.34).

CONCLUSIONS

OCT-guided primary PCI for ST-segment-elevation myocardial infarction was associated with a larger final in-stent minimum lumen diameter. There was no significant difference in clinical outcomes at 1 year; however, the study was underpowered to detect a treatment effect.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01149044.

Thrombus Aspiration in ST-Segment-Elevation Myocardial Infarction: An Individual Patient Meta-Analysis: Thrombectomy Trialists Collaboration

BACKGROUND

Thrombus aspiration during percutaneous coronary intervention (PCI) for the treatment of ST-segment-elevation myocardial infarction (STEMI) has been widely used; however, recent trials have questioned its value and safety. In this meta-analysis, we, the trial investigators, aimed to pool the individual patient data from these trials to determine the benefits and risks of thrombus aspiration during PCI in patients with ST-segment-elevation myocardial infarction.

METHODS

Included were large (n≥1000), randomized, controlled trials comparing manual thrombectomy and PCI alone in patients with ST-segment-elevation myocardial infarction. Individual patient data were provided by the leadership of each trial. The prespecified primary efficacy outcome was cardiovascular mortality within 30 days, and the primary safety outcome was stroke or transient ischemic attack within 30 days.

RESULTS

The 3 eligible randomized trials (TAPAS [Thrombus Aspiration During Percutaneous Coronary Intervention in Acute Myocardial Infarction], TASTE [Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia], and TOTAL [Trial of Routine Aspiration Thrombectomy With PCI Versus PCI Alone in Patients With STEMI]) enrolled 19 047 patients, of whom 18 306 underwent PCI and were included in the primary analysis. Cardiovascular death at 30 days occurred in 221 of 9155 patients (2.4%) randomized to thrombus aspiration and 262 of 9151 (2.9%) randomized to PCI alone (hazard ratio, 0.84; 95% confidence interval, 0.70-1.01; P=0.06). Stroke or transient ischemic attack occurred in 66 (0.8%) randomized to thrombus aspiration and 46 (0.5%) randomized to PCI alone (odds ratio, 1.43; 95% confidence interval, 0.98-2.10; P=0.06). There were no significant differences in recurrent myocardial infarction, stent thrombosis, heart failure, or target vessel revascularization. In the subgroup with high thrombus burden (TIMI [Thrombolysis in Myocardial Infarction] thrombus grade ≥3), thrombus aspiration was associated with fewer cardiovascular deaths (170 [2.5%] versus 205 [3.1%]; hazard ratio, 0.80; 95% confidence interval, 0.65-0.98; P=0.03) and with more strokes or transient ischemic attacks (55 [0.9%] versus 34 [0.5%]; odds ratio, 1.56; 95% confidence interval, 1.02-2.42, P=0.04). However, the interaction P values were 0.32 and 0.34, respectively.

CONCLUSIONS

Routine thrombus aspiration during PCI for ST-segment-elevation myocardial infarction did not improve clinical outcomes. In the high thrombus burden group, the trends toward reduced cardiovascular death and increased stroke or transient ischemic attack provide a rationale for future trials of improved thrombus aspiration technologies in this high-risk subgroup.

CLINICAL TRIAL REGISTRATION

URLs: http://www.ClinicalTrials.gov http://www.crd.york.ac.uk/prospero/. Unique identifiers: NCT02552407 and CRD42015025936.

Clinical Impact of Suboptimal Stenting and Residual Intrastent Plaque/Thrombus Protrusion in Patients With Acute Coronary Syndrome

Background—

Clinical consequences of optical coherence tomographic (OCT) high-definition visualization of plaque/stent structures in acute patients remain undefined. In this retrospective substudy, we assessed the prognostic impact of postprocedural culprit lesion OCT findings in patients with acute coronary syndrome undergoing percutaneous coronary intervention.

Methods and Results—

In the CLI-OPCI (Centro per la Lotta Contro L’Infarto-Optimization of Percutaneous Coronary Intervention) database collecting cases from 5 independent OCT-experienced centers, we retrospectively analyzed postprocedural OCT findings in acute coronary syndrome patients and explored its possible impact (specifically that of residual intrastent plaque/thrombus protrusion) on outcome. From 2009 to 2013, 507 patients (588 lesions) were evaluated. Patients experiencing device-oriented cardiovascular events showed more frequently the features of suboptimal stent implantation defined as the presence of significant residual intrastent plaque/thrombus protrusion (hazard ratio [HR], 2.35; P <0.01), in-stent minimum lumen area (MLA) <4.5 mm 2 (HR, 2.72; P <0.01), dissection >200 µm at distal stent edge (HR, 3.84; P <0.01), and reference lumen area <4.5 mm 2 at either distal (HR, 6.07; P <0.001) or proximal (HR, 8.50; P <0.001) stent edges. Postprocedural OCT assessment of treated culprit lesion revealed at least one of these parameters in 55.2% of cases, with an associated increased risk of device-oriented cardiovascular events during follow-up (17.9% versus 4.8%; P <0.001). Both the presence of at least one of these parameters (HR, 3.69; P =0.002) and the residual intrastent plaque/thrombus protrusion (HR, 2.83; P =0.008) were confirmed as independent predictors of device-oriented cardiovascular events.

Conclusions—

In this retrospective study of acute coronary syndrome patients undergoing percutaneous coronary intervention, a composite of OCT-defined suboptimal stent implantation characteristics at the culprit lesion and residual intrastent plaque/thrombus protrusion was associated with adverse outcome.

Outcome of 1051 Octogenarian Patients With ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention: Observational Cohort From the London Heart Attack Group

BACKGROUND

ST-segment elevation myocardial infarction is increasingly common in octogenarians, and optimal management in this cohort is uncertain. This study aimed to describe the outcomes of octogenarians with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention.

METHODS AND RESULTS

We analyzed 10 249 consecutive patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention between 2005 and 2011 at 8 tertiary cardiac centers across London, United Kingdom. The primary end point was all-cause mortality at a median follow-up of 3 years. In total, 1051 patients (10.3%) were octogenarians, with an average age of 84.2 years, and the proportion increased over the study period (P=0.04). In-hospital mortality (7.7% vs 2.4%, P<0.0001) and long-term mortality (51.6% vs 12.8%, P<0.0001) were increased in octogenarians compared with patients aged <80 years, and age was an independent predictor of mortality in a fully adjusted model (hazard ratio 1.07, 95% CI 1.07-1.09, P<0.0001). Time-stratified analysis revealed an increasingly elderly and more complex cohort over time. Nonetheless, long-term mortality rates among octogenarians remained static over time, and this may be attributable to improved percutaneous coronary intervention techniques, including significantly higher rates of radial access and lower bleeding complications. Variables associated with bleeding complications were similar between octogenarian and younger cohorts.

CONCLUSIONS

In this large registry, octogenarians undergoing primary percutaneous coronary intervention had a higher rate of complications and mortality compared with a younger population. Over time, octogenarians undergoing primary percutaneous coronary intervention increased in number, age, and complexity. Nevertheless, in-hospital outcomes were reasonable, and long-term mortality rates were static.

Thrombosis in ST-elevation myocardial infarction: Insights from thrombi retrieved by aspiration thrombectomy

In patients with ST-elevation myocardial infarction, recurrent cardiovascular events still remain the main cause of morbidity and mortality, despite significant improvements in antithrombotic therapy. We sought to review data regarding coronary thrombus analysis provided by studies using manual aspiration thrombectomy (AT), and to discuss how insights from this line of investigation could further improve management of acute coronary disease. Several studies investigated the fresh specimens retrieved by AT using techniques such as traditional morphological evaluation, optical microscopy, scanning electron microscopy, magnetic resonance imaging, and immunohistochemistry. These approaches have provided a better understanding of the composition and dynamics of the human coronary thrombosis process, as well as its relationship with some clinical outcomes. Recent data signaling to new antithrombotic therapeutic targets are still emerging.

Acute Myocardial Infarction/Thrombectomy

This article focuses on specialized techniques and devices used in the most challenging cases of acute myocardial infarction. Areas where high-quality evidence is either clear or absent are avoided. Controversies in the use of support or thrombectomy devices, the addition of adjunct pharmacology, and the decision to treat nonculprit lesions are discussed. Recent years have seen a shift in guidelines to downgrading the use of assist devices in cardiogenic shock and aspiration thrombectomy, whereas consideration of nonculprit coronary intervention has been revived. These changes come in the wake of a series of large, practice-changing clinical trials.

Manual aspiration thrombectomy devices use in coronary interventions in 2016

Percutaneous coronary intervention is a highly effective therapy of acute myocardial infarction. Restoration of microcirculation is however often sub-optimal with negative impact on patient outcome. Distal thrombus embolization may contribute to this issue. Simple manual aspiration thrombectomy catheters were developed with aim of thrombus extraction. There are several of these devices with very similar design. Thrombotic or atheromatous tissue is successfully retrieved in over 70% of patients. The initial results of small, often single center studies have provided encouraging results. Unfortunately, three further studies clearly demonstrated lack of any clinical benefit and routine use of manual aspiration thrombectomy cannot be recommended. Small but statistically significant increase in stroke rate is the major safety issue. Selective use in patients with large thrombus burden or suboptimal flow or perfusion is likely to continue and needs to be scientifically studied.

Thrombus aspiration in acute myocardial infarction: concepts, clinical trials, and current guidelines

The pathogenesis that underlies acute myocardial infarction is complex and multifactorial. One of the most important components, however, is the role of thrombus formation following atherosclerotic plaque rupture, leading to sudden coronary occlusion and subsequent ischemia and infarction. Thrombus aspiration provides the opportunity of intracoronary clot extraction with the aim to improve coronary and myocardial perfusion, by reducing the risk of no-reflow secondary to distal embolization of thrombus. The utility of thrombus aspiration during primary percutaneous coronary intervention has been assessed in an increasing number of observational and randomized studies. This article reviews the contemporary data and provides insights into the validity of thrombus aspiration in the setting of acute myocardial infarction.

Outcomes after thrombus aspiration for ST elevation myocardial infarction: 1-year follow-up of the prospective randomised TOTAL trial

BACKGROUND

Two large trials have reported contradictory results at 1 year after thrombus aspiration in ST elevation myocardial infarction (STEMI). In a 1-year follow-up of the largest randomised trial of thrombus aspiration, we aimed to clarify the longer-term benefits, to help guide clinical practice.

METHODS

The trial of routine aspiration ThrOmbecTomy with PCI versus PCI ALone in Patients with STEMI (TOTAL) was a prospective, randomised, investigator-initiated trial of routine manual thrombectomy versus percutaneous coronary intervention (PCI) alone in 10,732 patients with STEMI. Eligible adult patients (aged ≥18 years) from 87 hospitals in 20 countries were enrolled and randomly assigned (1:1) within 12 h of symptom onset to receive routine manual thrombectomy with PCI or PCI alone. Permuted block randomisation (with variable block size) was done by a 24 h computerised central system, and was stratified by centre. Participants and investigators were not masked to treatment assignment. The trial did not show a difference at 180 days in the primary outcome of cardiovascular death, myocardial infarction, cardiogenic shock, or heart failure. However, the results showed improvements in the surrogate outcomes of ST segment resolution and distal embolisation, but whether or not this finding would translate into a longer term benefit remained unclear. In this longer-term follow-up of the TOTAL study, we report the results on the primary outcome (cardiovascular death, myocardial infarction, cardiogenic shock, or heart failure) and secondary outcomes at 1 year. Analyses of the primary outcome were by modified intention to treat and only included patients who underwent index PCI. This trial is registered with ClinicalTrials.gov, number NCT01149044.

FINDINGS

Between Aug 5, 2010, and July 25, 2014, 10,732 eligible patients were enrolled and randomly assigned to thrombectomy followed by PCI (n=5372) or to PCI alone (n=5360). After exclusions of patients who did not undergo PCI in each group (337 in the PCI and thrombectomy group and 331 in the PCI alone group), the final study population comprised 10,064 patients (5035 thrombectomy and 5029 PCI alone). The primary outcome at 1 year occurred in 395 (8%) of 5035 patients in the thrombectomy group compared with 394 (8%) of 5029 in the PCI alone group (hazard ratio [HR] 1·00 [95% CI 0·87-1·15], p=0·99). Cardiovascular death within 1 year occurred in 179 (4%) of the thrombectomy group and in 192 (4%) of 5029 in the PCI alone group (HR 0·93 [95% CI 0·76-1·14], p=0·48). The key safety outcome, stroke within 1 year, occurred in 60 patients (1·2%) in the thrombectomy group compared with 36 (0·7%) in the PCI alone group (HR 1·66 [95% CI 1·10-2·51], p=0·015).

INTERPRETATION

Routine thrombus aspiration during PCI for STEMI did not reduce longer-term clinical outcomes and might be associated with an increase in stroke. As a result, thrombus aspiration can no longer be recommended as a routine strategy in STEMI.

FUNDING

Canadian Institutes of Health Research, Canadian Network and Centre for Trials Internationally, and Medtronic Inc.