A Comparison of 2 Thrombus Aspiration Devices With Histopathological Analysis of Retrieved Material in Patients Presenting With ST-Segment Elevation Myocardial Infarction

Dual Role of Guide Extension Catheters for the Management of High Thrombus Burden in STEMI: Case Report and Mini Review

High thrombus burden in ST segment elevation myocardial infarction (STEMI) patients increases the risk of adverse events. In this report, we review current strategies for high thrombus burden and present a case report with the combination of two different techniques: aspiration through a guide extension catheter followed by local intracoronary thrombolysis with 'marinade' technique.

Intracoronary thrombolysis and stentless primary percutaneous coronary intervention in an ectatic right coronary artery with large thrombus burden

A 58-year-old man was admitted to our center with an inferior ST-segment elevation myocardial infarction. A coronary angiogram showed an ectatic right coronary artery (RCA) occluded at mid vessel by a significant clot burden quantified by micro-computed tomography. Guide catheter-directed intracoronary thrombolysis with low-dose tenekteplase resulted in regaining RCA flow, when numerous efforts of manual and 'mother-child' thrombectomy had failed to achieve. A stentless strategy was followed with final thrombolysis in myocardial infarction 3 flow and angiographically insignificant stenosis remaining in the RCA. The combination of intracoronary thrombolysis and a stentless strategy is a safe and effective treatment in ST-segment elevation myocardial infarction patients with ectatic arteries and large thrombus burden when repeat manual aspiration thrombectomy fails.

Effect of intracoronary tirofiban following aspiration thrombectomy on infarct size, in patients with large anterior ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Myocardial recovery following primary percutaneous coronary intervention is often suboptimal despite of restoration of thrombolysis in myocardial infarction (TIMI) 3 flow, in part due to thrombus embolization which results in impairing microvascular reperfusion besides increasing infarct size. The purpose of the present study was to estimate the effect of aspiration thrombectomy followed by intracoronary delivery of tirofiban on decreasing the infarct size utilizing cardiac MRI (cMR) in large anterior ST-segment elevation myocardial infarction (STEMI) patients.

PATIENTS

A prospective randomized controlled study of 100 patients with large anterior STEMI were randomized to (Study group) using intracoronary tirofiban (intracoronary) and (control group) without intocoronary tirofiban. A 6 F thrombus aspiration catheter was used in all patients. Tirofiban was injected locally at the place of the highly thrombus burden through the aspiration device after flushing the aspiration device well.

RESULTS

Patients of intracoronary tirofiban group compared with control group had a significant difference in decreasing the infarct size at 30 days [median, 15.451 g - interquartile range (IQR), 17.404 gm - n = 50] vs (median, 43.828 g - IQR, 49.599 g - n = 50) P value = 0.002.

CONCLUSION

In patients early presented with large anterior STEMI, infarct size at 30 days was significantly decreased by intracoronary tirofiban delivered to the infarct lesion site followed aspiration thrombectomy.

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.

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.

The role of diabetes mellitus in the composition of coronary thrombi in patients presenting with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Although diabetes mellitus (DM) is a predictor of poor outcomes in patients with ST-segment elevation myocardial infarction (STEMI), few studies have analyzed the impact of DM on the constituency of coronary thrombi.

OBJECTIVES

Comparing morphologic and histopathologic aspects of coronary thrombi in STEMI patients with and without DM who underwent primary percutaneous coronary intervention.

METHODS

All consecutive patients with STEMI admitted to our institution between April 2010 and December 2012 (n = 1,548) were considered for inclusion. Thrombus material was obtained by aspiration thrombectomy; morphologic and histopathologic aspects were assessed by 3 independent pathologists blinded to clinical characteristics and outcomes. Patients with DM were compared with those without DM. A sensitivity analysis was performed using a propensity score.

RESULTS

During the study period, coronary thrombi material from 259 patients was obtained, of whom 19% (n = 49) had diabetes. Diabetic patients were older (P = .10), had a higher frequency of hypertension (P < .01) and dyslipidemia (P = .03), and had a trend to a longer time from the onset of chest pain to hospital arrival (P = .08). The number of retrieved fragments, the size of the thrombi and its composition (leukocytes, fibrin, and erythrocytes percent), and thrombus age and color were similar between patients with or without DM. There were also no statistically significant differences in thrombus constituency of the propensity score-matched patients (n = 92).

CONCLUSIONS

In this study, morphologic and histopathologic constituency of coronary thrombi in the setting of a ST-elevation myocardial infarction was not significantly different between patients with or without DM. This finding was intriguing and deserves further investigation.

A novel model for evaluating thrombolytic therapy in dogs with ST-elevation myocardial infarction

Background

There is still no standard large animal model for evaluating the effectiveness of potential thrombolytic therapies. Here, we aimed to develop a new beagle model with ST-elevation myocardial infarction (STEMI) by injecting autologous emboli with similar components of coronary thrombus.

Methods

18 male beagles were included and divided into three groups: red embolus group (n = 6), white embolus group (n = 6) or white embolus + rt-PA group (n = 6). Autologous emboli were infused into the mid-distal region of the left anterior descending coronary artery. The composition of embolus was examined by scanning electron microscope (SEM). Coronary angiography was performed to verify the status of embolism. Myocardial infarct size was measured by 2, 3, 5- triphenyltetrazolium chloride (TTC) staining.

Results

Red thrombus was characteristic of loose reticular structure of erythrocytes under SEM, while the white embolus had compacted structure that mainly consisted of a dense mass of fibrin. Coronary angiography showed the recanalization rate was 2/6 in the red embolus group versus 0/6 in the white embolus group in three hours after occlusion. Arrhythmia, resolution of ST-segment elevation and lower T wave on the electrocardiogram appeared in the red embolus group but not in the white embolus group. Another six dogs with white thrombi were treated with rt-PA. Five out of six dogs exhibited coronary recanalization after two hours of therapy, compared to zero dogs without rt-PA treatment. The size of myocardial infarction in rt-PA group reduced significantly compared with white embolus group using TTC staining method.

Conclusions

The white embolism model was more convenient experimentally and had a higher uniformity, stability and success rate. The major innovation of our study is that we applied fibrin-rich white thrombi to establish beagle model possessing features of clinically observed coronary thrombi in time window of intravenous thrombolysis of STEMI. This model can be used to evaluate new thrombolytic drugs for the treatment of STEMI.

Thrombus Aspiration in STEMI

OPINION STATEMENT

ST-segment elevation myocardial infarction (STEMI) remains an important cause of morbidity and mortality. In the USA, the development of an organized STEMI network has allowed STEMI patients greater access to primary PCI. The most important goal in the management of STEMI is timely reperfusion and establishment of normal coronary flow. However, periprocedural thrombus embolization, which can obstruct the distal microvasculature and impair tissue perfusion, is associated with unfavorable outcomes. Over the last years, aspiration thrombectomy has emerged as a novel technique to prevent distal coronary thromboembolism during primary PCI. The initial excitement after the publication of the TAPAS trial changed the practice paradigm among interventional community worldwide. Aspiration thrombectomy was recommended by several society guidelines and became the "standard of care" during primary PCI. However, recent data and publication of two large randomized controlled trials questioned the effectiveness (TASTE trial) and the safety (TOTAL trial) of this technique. Therefore, the recent ACC/AHA/SCAI-focused update document recommended against the routine use of manual thrombectomy during primary PCI. This review will summarize recent data and trials regarding thrombus aspiration in STEMI.

ST-elevation myocardial infarction, thrombus aspiration, and different invasive strategies. A TASTE trial substudy

BACKGROUND

The clinical effect of thrombus aspiration in ST-elevation myocardial infarction may depend on the type of aspiration catheter and stenting technique.

METHODS AND RESULTS

The multicenter, prospective, randomized, open-label trial Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia (TASTE) did not demonstrate a clinical benefit of thrombus aspiration compared to percutaneous coronary intervention alone. We assessed the effect of type of aspiration device, stent type, direct stenting, and postdilatation on outcomes at 1 year. There was no difference in all-cause mortality, between the 3 most frequently used aspiration catheters (Eliminate [Terumo] 5.4%, Export [Medtronic] 5.0%, Pronto [Vascular Solutions] 4.5%) in patients randomized to thrombus aspiration. There was no difference in mortality between directly stented patients randomized to thrombus aspiration compared to patients randomized to percutaneous coronary intervention only (risk ratio 1.08, 95% CI 0.70 to 1.67, P=0.73). Similarly, there was no difference in mortality between the 2 randomized groups for patients receiving drug-eluting stents (risk ratio 0.89, 95% CI 0.63 to 1.26, P=0.50) or for those treated with postdilation (risk ratio 0.72, 95% CI 0.49 to 1.07, P=0.11). Furthermore, there was no difference in rehospitalization for myocardial infarction or stent thrombosis between the randomized arms in any of the subgroups.

CONCLUSIONS

In patients with ST-elevation myocardial infarction randomized to thrombus aspiration, the type of aspiration catheter did not affect outcome. Stent type, direct stenting, or postdilation did not affect outcome irrespective of treatment with thrombus aspiration and percutaneous coronary intervention or percutaneous coronary intervention alone.

CLINICAL TRIAL REGISTRATION

URL: ClinicalTrials.gov. Unique identifier: NCT01093404, https://clinicaltrials.gov/ct2/show/NCT01093404.

Use of Thrombectomy Devices in Primary Percutaneous Interventions for ST-elevation Myocardial Infarction - An Update

Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion modality in patients with ST-elevation myocardial infarction (STEMI). While PPCI is highly effective in achieving epicardial coronary reperfusion, a significant proportion of patients fail to achieve adequate myocardial reperfusion. This is in part due to the distal microembolisation of thrombus and plaque debris during PCI. Recognition of this has led to the development of a number of devices with different mechanisms of action that aim to reduce such distal embolisation and therefore improve end myocardial perfusion. Study results of thrombectomy devices however have been largely inconsistent, especially about clinical outcome data, and several meta-analyses have been carried out as a result. This review aims to critically analyse the literature data on thrombectomy during PPCI, taking into account the most recent studies and the latest meta-analyses looking to see whether thrombectomy use is associated with improved outcomes.

Utility of Thrombectomy in Primary Percutaneous Coronary Intervention

Thrombectomy in the setting of primary percutaneous coronary intervention allows for improved macrovascular and microvascular perfusion, possible limitation of infarct size, and the preservation of left ventricular function and myocardial viability. The beneficial tissue level effects of thrombectomy have translated into an improvement in cardiovascular mortality. A variety of thrombectomy devices are currently available, including aspiration thrombectomy catheters and rheolytic catheters. A review of the various types of thrombectomy devices available, clinical evidence for their use, clinical pearls for use, and device troubleshooting are presented.

Bacterial signatures in thrombus aspirates of patients with myocardial infarction

BACKGROUND

Infectious agents, especially bacteria and their components originating from the oral cavity or respiratory tract, have been suggested to contribute to inflammation in the coronary plaque, leading to rupture and the subsequent development of coronary thrombus. We aimed to measure bacterial DNA in thrombus aspirates of patients with ST-segment-elevation myocardial infarction and to check for a possible association between bacteria findings and oral pathology in the same cohort.

METHODS AND RESULTS

Thrombus aspirates and arterial blood from patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention (n=101; 76% male; mean age, 63.3 years) were analyzed with real-time quantitative polymerase chain reaction with specific primers and probes to detect bacterial DNA from several oral species and Chlamydia pneumoniae. The median value for the total amount of bacterial DNA in thrombi was 16 times higher than that found in their blood samples. Bacterial DNA typical for endodontic infection, mainly oral viridans streptococci, was measured in 78.2% of thrombi, and periodontal pathogens were measured in 34.7%. Bacteria-like structures were detected by transmission electron microscopy in all 9 thrombus samples analyzed; whole bacteria were detected in 3 of 9 cases. Monocyte/macrophage markers for bacteria recognition (CD14) and inflammation (CD68) were detected in thrombi (8 of 8) by immunohistochemistry. Among the subgroup of 30 patients with myocardial infarction examined by panoramic tomography, a significant association between the presence of periapical abscesses and oral viridans streptococci DNA-positive thrombi was found (odds ratio, 13.2; 95% confidence interval, 2.11-82.5; P=0.004).

CONCLUSIONS

Dental infection and oral bacteria, especially viridans streptococci, may be associated with the development of acute coronary thrombosis.

Pathophysiology of coronary thrombus formation and adverse consequences of thrombus during PCI

Atherosclerosis is a systemic vascular pathology that is preceded by endothelial dysfunction. Vascular inflammation "fuels" atherosclerosis and creates the milieu for episodes of intravascular thromboses. Thrombotic events in the coronary vasculature may lead to asymptomatic progression of atherosclerosis or could manifest as acute coronary syndromes or even sudden cardiac death. Thrombus encountered in the setting of acute coronary syndromes has been correlated with acute complications during percutaneous coronary interventions such as no-reflow, acute coronary occlusion and long term complications such as stent thrombus. This article reviews the pathophysiology of coronary thrombogenesis and explores the complications associated with thrombus during coronary interventions.

Relation of ruptured plaque culprit lesion phenotype and outcomes in patients with ST elevation acute myocardial infarction

We used virtual histology intravascular ultrasound (VH-IVUS) to assess culprit plaque rupture in 172 patients with ST-segment elevation acute myocardial infarction. VH-IVUS-defined thin-capped fibroatheroma (VH-TCFA) had necrotic core (NC) > 10% of plaque area, plaque burden > 40%, and NC in contact with the lumen for ≥ 3 image slices. Ruptured plaques were present in 72 patients, 61% of which were located in the proximal 30 mm of a coronary artery. Thirty-five were classified as VH-TCFA and 37 as non-VH-TCFA. Vessel size, lesion length, plaque burden, minimal lumen area, and frequency of positive remodeling were similar in VH-TCFA and non-VH-TCFA. However, the NC areas within the rupture sites of VH-TCFAs were larger compared to non-VH-TCFAs (p = 0.002), while fibrofatty plaque areas were larger in non-VH-TCFAs (p < 0.0001). Ruptured plaque cavity size was correlated with distal reference lumen area (r = 0.521, p = 0.00002), minimum lumen area (r = 0.595, p < 0.0001), and plaque area (r = 0.267, p = 0.033). Sensitivity and specificity curve analysis showed that a minimum lumen area of 3.5 mm2, a distal reference lumen area of 7.5 mm2, and a maximum NC area of 35% best predicted plaque rupture. Although VH-TCFA (35 of 72) was the most frequent phenotype of plaque rupture in ST-segment elevation myocardial infarction, plaque rupture also occurred in non-VH-TCFA: pathologic intimal thickening (8 of 72), thick-capped fibroatheroma (1 of 72), and fibrotic (14 of 72) and fibrocalcified (14 of 72) plaque. In conclusion, not all culprit plaque ruptures in patients with ST-segment elevation myocardial infarction occur as a result of TCFA rupture; a prominent fibrofatty plaque, especially in a proximal vessel, may be another form of vulnerable plaque. Further study should identify additional factors causing plaque rupture.

Lessons from human coronary aspirate

The interventional implantation of a stent into an atherosclerotic coronary artery is a unique and paradigmatic scenario of plaque rupture in humans. The use of protection devices not only prevents the released plaque particles and the superimposed thrombotic material from being washed and embolized into the coronary microcirculation of the individual patient, but permits also the retrieval and ex vivo analysis of particulate plaque debris and soluble substances. The particulate debris comprises typical cholesterol crystals, foam cells, hyalin material and calcium deposits from the atheroma as well as platelets and coagulation material; soluble substances include vasoconstrictors, such as serotonin and thromboxane, as well as inflammatory mediators, such as TNFα which amplifies vasoconstriction by inducing endothelial dysfunction. The vasoconstriction observed in a bioassay ex vivo correlates to clinical symptoms, angiographic stenosis and plaque burden, as assessed by intravascular ultrasound. The release of TNFα into the aspirate correlates to restenosis. Detailed analysis of the human coronary aspirate may promote a better understanding of the pathophysiology of the vulnerable atherosclerotic plaque and help to better antagonize the microvascular consequences of coronary microembolization, including the no reflow phenomenon. This article is part of a Special Issue entitled "Coronary Blood Flow."

[Impact of the angles and the age of the thrombus on efficacity of thromboaspiration device. A bench study]

INTRODUCTION

Coronary thrombectomy is usually used to treat acute coronary syndrome. Many studies evaluated its benefit in this context however, it is still unknown if coronary characteristics are predictive of success or failure. The aim of our laboratory bench study was to evaluate the impact of angiographic characteristics on the thromboaspiration efficiency.

METHODS

Glass tubes of 150 mm in the length were used, with five diameters: 2; 2.6; 3; 3.6 and 4 mm; and for each diameter, three angulations: no angulation; 90° and 120°. Blood sample were taken from healthy subject and thrombi of 3 and 6 hours old were performed, with a constant volume for each test. Thromboaspirations were performed with an Export(®) catheter (Medtronic). The primary endpoint was total thrombectomy. A total of 240 thromboaspirations were performed.

RESULTS

A total thrombectomy was obtained for 71.2% of the tests. It was achieved more frequently with the smaller diameter, respectively: 100% for 2 mm, 81.3% for 2.6 mm, 89.6% for 3 mm vs 54.2% for 3.6 mm and 31.3% for 4 mm (P<0.001). No differences were observed between the 2 thrombi ages (73.3% for the 3 hours old thrombi and 69.2% for the 6 hours old thrombi, P = 0.476), nor between the three tube's angulations (77.5% for no angle, 66.3% for 90° and 70.0% for 120°, P = 0.278).

RESULTS AND CONCLUSION

This study shows an impact of the coronary diameters on the rate of thromboaspiration success with an Export(®) catheter. Beyond 3 mm of diameter, the rate of success is divided by 2: for diameters less or equal to 3 mm, 90.3% of success vs 42.7% for diameters greater than 3 mm (P<0.001). There is no difference of efficiency between the 3 and 6 hours old thrombi, neither between the tube's angulations. However, this is a preliminary and further works are needed to clarify how to optimize the aspiration and the impact of other catheters.

Impact of thrombus aspiration use and direct stenting on final myocardial blush score in patients presenting with ST-elevation myocardial infarction

BACKGROUND

Many studies have reported that low final thrombolysis in myocardial infarction (TIMI) flow and/or myocardial blush grade (MBG) are independent predictors of mortality in patients with ST-elevation myocardial infarction (STEMI). In addition, distal coronary embolization is a major pitfall of conventional percutaneous coronary intervention (PCI) in such a context.

AIM

This study aimed to assess the impact of thrombus aspiration (TA) use before primary PCI on final myocardial reperfusion in patients presenting with STEMI.

METHODS

From January to December 2006, 100 patients presenting with STEMI in our catheterization laboratory were considered for the present study. During this time period, 50 patients underwent TA before primary PCI for treatment of STEMI and were then matched 1:1 to 50 controls who underwent conventional primary PCI for treatment of STEMI without TA. Patients of the control group were chosen after matching on age+/-3 years, sex, history of diabetes, and distribution of the infarct related coronary artery during the same period.

RESULTS

Baseline clinical characteristics, initial TIMI flow and initial MBG of both groups were similar. There was a trend for a better final TIMI flow in the group with TA and the final MBG was significantly improved in the group with TA compared to the group without TA: final MBG of two or three in 70% versus 30% of the cases (P=.001). In addition, direct stenting was significantly more often used in the TA group (92% versus 64%, P=.001). There were four patients with evident distal embolizations in the group without TA and none in the group with TA.

CONCLUSION

TA use before primary PCI for STEMI treatment resulted in improved final myocardial reperfusion. Of importance, TA use may have led to a better choice of the stent size and more frequent direct stenting. This benefit may directly improve patient outcomes.

Is the myocardial blush grade scored by the operator during primary percutaneous coronary intervention of prognostic value in patients with ST-elevation myocardial infarction in routine clinical practice?

BACKGROUND

Multiple trials have documented that myocardial blush grade (MBG) after primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) has prognostic value for long-term clinical outcome. However, to the best of our knowledge, no study has determined the clinical use of MBG in routine clinical practice. We determined the prognostic value of MBG scored by the operator during primary PCI in consecutive patients with STEMI.

METHODS AND RESULTS

The prognostic value of MBG scored by the operator in relation to 1-year all cause mortality was evaluated in all patients with STEMI who underwent primary PCI between January 2004 and July 2008 in our hospital. The incidence of MBG 0, 1, 2, and 3 was 12%, 14%, 36%, and 38%, respectively, in 2118 consecutive patients with STEMI. Follow-up of all 2118 patients showed a 1-year all cause mortality rate of 8% (168 of 2118): 24%, 10%, 6%, and 4%, respectively, among patients with MBG 0, 1, 2, and 3 (P<0.001). In the 1763 patients with Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 after PCI, these mortality rates were 17%, 10%, 6%, and 4%, respectively (P<0.001). MBG scored by the operator was a strong independent predictor of 1-year all cause mortality corrected for other well-known predictive variables, including TIMI flow grade.

CONCLUSIONS

MBG scored by the operator during primary PCI has prognostic value for 1-year all cause mortality in patients with STEMI in routine clinical practice. Therefore, the MBG should be documented, in addition to the TIMI flow grade, during primary PCI in patients with STEMI in standard PCI reports in routine clinical practice.

Coronary microembolization: from bedside to bench and back to bedside

Coronary microembolization from the erosion or rupture of a vulnerable atherosclerotic plaque occurs spontaneously in acute coronary syndromes and iatrogenically during percutaneous coronary interventions. Typical consequences of coronary microembolization are microinfarcts with an inflammatory response, contractile dysfunction, and reduced coronary reserve. Apart from transient elevations of creatine kinase and troponin, microemboli can be visualized by intracoronary Doppler and the resulting microinfarcts by late-enhancement nuclear magnetic resonance. Statins, antiplatelet agents, and coronary vasodilators protect against microembolization and microinfarction when started before percutaneous coronary interventions. Distal protection devices can retrieve atherothrombotic debris and prevent its embolization into the microcirculation, but their effect on clinical outcome has been disappointing so far, except for saphenous vein bypass grafts. Devices for aspiration of thrombi and thrombus-derived vasoconstrictor, thrombogenic, and inflammatory substances, however, reduce thrombus burden, improve perfusion, and provide protection in patients with acute myocardial infarction.