Role of Aspiration and Mechanical Thrombectomy in Patients With Acute Myocardial Infarction Undergoing Primary Angioplasty

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.

Efficacy of thrombus aspiration in cardiogenic shock complicating acute myocardial infarction and high thrombus burden

INTRODUCTION AND OBJECTIVES

Current guidelines do not recommend routine thrombus aspiration in acute myocardial infarction (AMI) because no benefits were observed in previous randomized trials. However, there are limited data in cardiogenic shock (CS) complicating AMI.

METHODS

We included 575 patients with AMI complicated by CS. The participants were stratified into the TA and no-TA groups based on use of TA. The primary outcome was a composite of 6-month all-cause death or heart failure rehospitalization. The efficacy of TA was additionally assessed based on thrombus burden (grade I-IV vs V).

RESULTS

No significant difference was found in in-hospital death (28.9% vs 33.5%; P=.28), or 6-month death, or heart failure rehospitalization (32.4% vs 39.4%; HRadj: 0.80; 95%CI, 0.59-1.09; P=.16) between the TA and no-TA groups. However, in 368 patients with a higher thrombus burden (grade V), the TA group had a significantly lower risk of 6-month all-cause death or heart failure rehospitalization than the no-TA group (33.4% vs 46.3%; HRadj: 0.59; 95%CI, 0.41-0.85; P=.004), with significant interaction between thrombus burden and use of TA for primary outcome (adjusted Pint=.03).

CONCLUSIONS

Routine use of TA did not reduce short- and mid-term adverse clinical outcomes in patients with AMI complicated by CS. However, in select patients with a high thrombus burden, the use of TA might be associated with improved clinical outcomes. The study was registered at ClinicalTrials.gov (Identifier: NCT02985008).

Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy

Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.

Outcomes of thrombus aspiration during primary percutaneous coronary intervention for ST-elevation myocardial infarction

BACKGROUND

Previous large multi-centre randomised controlled trials have not provided clear benefit with routine intracoronary thrombus aspiration (TA) as an adjunct to primary percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI).

AIM

To determine whether there is a difference in outcomes with the use of manual TA prior to PCI, compared with PCI alone in a cohort of patients with STEMI.

METHODS

We analysed data from 6270 consecutive patients undergoing primary PCI for STEMI prospectively enrolled in the Melbourne Interventional Group registry between 2007 and 2018. Multivariable analysis was performed to determine predictors of 30-day major adverse cardiovascular and cerebrovascular events (MACCE) and long-term mortality.

RESULTS

We compared 1621 (26%) patients undergoing primary PCI with TA to 4649 (74%) patients undergoing PCI alone. Male gender (81% vs 78%; P < 0.01), younger age (61 vs 63 years; P = 0.03), GP-IIb/IIIa use (76% vs 58%, P < 0.01), and current smoking (40% vs 36%; P < 0.01) were more common in the TA group. TA was more likely to be used in patients with complex lesions (83% vs 66%; P < 0.01) with TIMI 0 flow (77% vs 56%; P < 0.01). No significant difference in post-procedural TIMI flow, stroke, 30-day mortality, or long-term mortality were identified. Multivariable analysis demonstrated a reduction in 30-day MACCE (hazard ratio (HR) 0.75; confidence interval (CI) 0.63-0.89; P < 0.01) in the TA group, but was not associated with long-term mortality (HR 0.98; CI 0.85-1.1; P = 0.73).

CONCLUSION

The use of TA in patients undergoing primary PCI for STEMI was not associated with improved short or long-term mortality when compared with PCI alone.

Novel Application of Large Bore Aspiration in the Treatment of COVID-19 Associated Acute Limb Ischemia Using the Penumbra CAT 12 Lightning Aspiration System

COVID-19 associated cardiovascular complications have been well documented throughout the pandemic and are associated with higher rates of morbidity and mortality. Hypercoagulable states resulting from systemic inflammation have been associated with increasing incidences of acute myocardial infarctions (AMI) and acute limb ischemia (ALI). Herein, we present a case of AMI complicated by ALI in a patient with COVID-19 in which aspiration thrombectomy using the Penumbra CAT 12 thrombectomy catheter was used in the management of acute popliteal artery occlusion.

Aspiration thrombectomy: safe removal of thrombi too big to aspirate

Aspiration thrombectomy has been associated with an increased risk of stroke, and its routine use is not recommended. Ill-defined procedural techniques for aspiration thrombectomy may provide an explanation for inconsistent outcomes and adverse event rates in trials. Large thrombi can plug the aspiration port of the aspiration catheter and then be dislodged into the central circulation when they are retracted into the guide catheter, or when the aspiration catheter is removed from the Tuohy connector. We report a case of thrombus aspiration where a large distal thrombus was aspirated into the mouth of the aspiration catheter, held there with suction as it was removed and delivered outside the body without being dislodged. We offer several tips for safe removal of coronary thrombi too big to aspirate.

Mechanisms of the "No-Reflow" Phenomenon After Acute Myocardial Infarction: Potential Role of Pericytes

Pericytes contract during myocardial ischemia resulting in capillary constriction and no reflow. Reversing pericyte contraction pharmacologically reduces no reflow and infarct size. These findings open up an entire new venue of research aimed at altering pericyte function in myocardial ischemia and infarction.

The effect of serum uric acid concentration on the severity of chronic congestive heart failure

This study aimed to investigate the adverse effects of serum uric acid concentration on the severity of chronic congestive heart failure. One hundred patients with chronic congestive heart failure (several risk factors include hypertension, smoking, and diabetes mellitus) were enrolled in this study (51 females and 49 males). Participants were admitted to Alsader Medical City in Al-Najaf from August 2018 to March 2019. Detailed medical history and complete clinical examination were performed for all patients. The patients' ages ranged from 13-90 years, with a mean of 62.1±15.8 years, and the median was 65 years. No statistically significant age difference was observed between males and females (P-value=0.687). Increased serum uric acid had a directly negative effect on the severity of chronic congestive heart failure and hypertension. High serum uric acid concentration was associated with increased severity of chronic congestive heart failure class NYHA III and NYHA IV and a decrement in ejection fraction of the left ventricle.

Mechanism and potential treatment of the "no reflow" phenomenon after acute myocardial infarction: role of pericytes and GPR39

The "no reflow" phenomenon, where the coronary artery is patent after treatment of acute myocardial infarction (AMI) but tissue perfusion is not restored, is associated with worse outcome. The mechanism of no reflow is unknown. We hypothesized that pericytes contraction, in an attempt to maintain a constant capillary hydrostatic pressure during reduced coronary perfusion pressure, causes capillary constriction leading to no reflow and that this effect is mediated through the orphan receptor, GPR39, present in pericytes. We created AMI (coronary occlusion followed by reperfusion) in GPR39 knock out mice and littermate controls. In a separate set of experiments, we treated wild-type mice undergoing coronary occlusion with vehicle or VC43, a specific inhibitor of GPR39, before reperfusion. We found that no reflow zones were significantly smaller in the GPR39 knockouts compared with controls. Both no reflow and infarct size were also markedly smaller in animals treated with VC43 compared with vehicle. Immunohistochemistry revealed greater capillary density and larger capillary diameter at pericyte locations in the GPR39-knockout and VC43-treated mice compared with controls. We conclude that GPR39-mediated pericyte contraction during reduced coronary perfusion pressure causes capillary constriction resulting in no reflow during AMI and that smaller no reflow zones in GPR39-knockout and VC43-treated animals are associated with smaller infarct sizes. These results elucidate the mechanism of no reflow in AMI, as well as providing a therapeutic pathway for the condition.NEW & NOTEWORTHY The mechanism of "no reflow" phenomenon, where the coronary artery is patent after treatment of acute myocardial infarction but tissue perfusion is not restored, is unknown. This condition is associated with worse outcome. Here, we show that GPR39-mediated pericyte contraction during reduced coronary perfusion pressure causes capillary constriction resulting in no reflow. Smaller no-reflow zones in GPR39-knockout animals and those treated with a GPR39 inhibitor are associated with smaller infarct size. These results could have important therapeutic implications.

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.

Thrombus aspiration during primary percutaneous coronary intervention improved outcome in patients with STEMI and a large thrombus burden

Background

The benefit of thrombus aspiration (TA) during primary percutaneous coronary intervention (PPCI) to patients with ST-segment elevation myocardial infarction (STEMI) remains controversial. This study aimed to assess TA's impact on the outcome and prognosis for patients with STEMI and a large thrombus burden during PPCI.

Methods

This retrospective study evaluated consecutive patients with STEMI and a large thrombus burden (thrombolysis in myocardial infraction [TIMI] thrombus grade ≥4) who underwent conventional PPCI (n = 126) or PPCI + TA (n = 208) between February 2017 and January 2019. The procedure outcome and clinical prognosis were compared.

Results

Postprocedural vessel diameter was larger, and corrected TIMI frame count (cTFC) was lower in the PPCI + TA compared with the PPCI group. The proportion of postprocedural TIMI 3 flow was 83.3% in the PPC group and 94.2% in the PPCI+TA group. During the 12-month follow-up, no significant differences existed in the incidence of cardiac death, reinfarction, stent thrombosis, target vessel revascularization, or stroke.

Conclusion

Application of TA in patients with STEMI and a large thrombus burden during PPCI may improve the procedural outcome, but it showed no benefit on the clinical prognosis in the 12-month follow-up. Longer follow-up studies are needed to confirm TA's clinical implications in patients with STEMI.

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 in Patients with Acute Myocardial Infarction-5-Year Analysis Based on a Large National Registry (ORPKI)

Blood flow restoration after primary percutaneous coronary intervention (pPCI) in patients with acute myocardial infarction (AMI) may not always be achieved and could be complicated by the no-reflow phenomenon (NRP). The aim of the current study was to assess the frequency of thrombus aspirations (TAs) and NRPs in patients with AMI and treated with pPCI based on the data collected during a 5-year period in the national ORPKI registry, as well as the frequency of periprocedural strokes and predictors of TA and NRP. This retrospective analysis was performed on prospectively collected data gathered in the Polish National Registry of Percutaneous Coronary Interventions (ORPKI), which covered the period between January 2014 and December 2018, and included 200,991 patients treated due to AMI out of 535,857 patients treated using PCI. Among them, 16,777 patients underwent TA. TA was mainly used in the STEMI subgroup of 14,207 patients (84.8%). The frequency of NRP among AMI patients in the thrombectomy group was 2.75% and in the non-thrombectomy group 0.82%. Predictors of TA and NRP were also assessed using multivariate analysis. The percentage of patients treated with pPCI and with PCI alone increased significantly in all of the three selected groups of patients from 88.7% to 94.3% in the AMI group (p < 0.001), from 82.3% to 90.3% in the STEMI subgroup (p < 0.001), and from 96.3% to 98.2% in the NSTEMI subgroup (p < 0.001) during the analysed period. NRP occurred more often in the thrombectomy group for the NSTEMI (0.58% vs. 3.07%, p < 0.05) and STEMI (1.06% vs. 2.69%, p < 0.05) subgroups. Periprocedural stroke occurred more often in the thrombectomy group in comparison to the non-thrombectomy group with AMI (0.03% vs. 0.01%, p < 0.05) and the NSTEMI (0.16% vs. 0.02%, p < 0.05). In conclusion, the frequency of TA has been experiencing a steady decline in recent years, regardless of AMI type, among patients treated with pPCI.

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.

Phospholipid-Coated Hydrophobic Mesoporous Silica Nanoparticles Enhance Thrombectomy by High-Intensity Focused Ultrasound with Low Production of Embolism-Inducing Clot Debris

Here we report the efficacy of a nanoparticle-assisted high-intensity focused ultrasound (HIFU) treatment that selectively destroys blood clots while minimizing generation of microparticles, or microemboli, that can cause further complications postsurgery. Treatment of malignant blood clots (thrombi) and the resulting emboli are critical problems for numerous patients, and treatments addressing these conditions would benefit from advancements in noninvasive procedures such as HIFU. While recanalization of occlusive blood clots is currently addressed with surgical intervention that seeks to minimize formation of large emboli, there is a danger of microemboli (micrometer-size particles) that have been theorized to be responsible for the poor correlation between apparent surgical success and patient outcome. Here, the addition of phospholipid-coated hydrophobically modified silica nanoparticles (P@hMSNs) improved the efficacy of HIFU treatment by serving as cavitation nuclei for mechanical disruption of thrombi. This treatment was evaluated for the ability to clear the HIFU focal area of a thick and dense thrombus within 10 min. Moreover, it was found that the use of P@hMSN+HIFU treatment generated a significantly smaller microembolic load as compared to comparison techniques, including a HIFU + microbubble contrast agent, HIFU alone, and direct mechanical disruption. This reduction in the microembolic load can occur either with primary removal of the clot by P@hMSN+HIFU or by insonation of the clot fragments after mechanical thrombectomy. Lastly, this method was evaluated in a flow model, where nonocclusive model thrombi and model emboli were mechanically ablated within the focal area within 15 s. Together, these results represent a combination therapy capable of resolving thrombi and microembolisms resulting from thrombectomy through localized destruction of clotted material.

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.

Impact of total ischemic time on manual thrombus aspiration benefit during primary percutaneous coronary intervention

BACKGROUND

The benefits of manual thrombus aspiration (TA) during primary percutaneous coronary intervention (pPCI) for ST-elevation myocardial infarction (STEMI) remain uncertain. We assessed the influence of total ischemic time (TIT) on clinical outcomes among STEMI patients undergoing manual TA during pPCI.

METHODS AND RESULTS

We conducted a retrospective study of patients enrolled in the Acute Myocardial Infarction in Switzerland Plus registry. STEMI patients undergoing pPCI with (TA group) or without (PCI-alone group) manual TA were stratified based on short (<3 hours), intermediate (3-6 hours), and long (>6 hours) TIT. The primary endpoint was in-hospital all-cause mortality. The secondary endpoint was in-hospital major adverse cardiac events (MACE), a composite of all-cause death, myocardial reinfarction and stroke. Between 2008 and 2014, 4'154 patients (TA 48%) were included. Risk-adjusted in-hospital all-cause mortality was not different between TA and PCI-alone groups (OR 1.29; 95%CI 0.83-1.98; p=0.26), whereas there was significantly increased risk of MACE (OR 1.52; 95%CI 1.05-2.19; p=0.03) in patients treated with manual TA compared with PCI-alone. There was no significant difference between manual TA and PCI-alone with respect to risk-adjusted all-cause mortality according to TIT groups, but risk-adjusted MACE rates were significantly higher in the group of patients with long TIT treated with manual TA compared with PCI-alone (OR 2.42; 95%CI 1.16-5.04; p=0.02).

CONCLUSION

In a large registry of STEMI patients, manual TA was not associated with lower risk-adjusted in-hospital all-cause mortality compared with PCI-alone regardless of TIT but was associated with significantly greater risk of MACE. In patients with prolonged TIT, manual TA was associated with higher risk-adjusted MACE rates compared with PCI-alone.

Efficacy and safety of thrombus aspiration in ST-segment elevation myocardial infarction: an updated systematic review and meta-analysis of randomised clinical trials

BACKGROUND:

The role of thrombus aspiration plus primary percutaneous coronary intervention in ST-segment elevation myocardial infarction remains controversial.

METHODS:

We performed a meta-analysis of 25 randomised controlled trials in which 21,740 ST-segment elevation myocardial infarction patients were randomly assigned to thrombus aspiration plus primary percutaneous coronary intervention or primary percutaneous coronary intervention. Study endpoints were: death, myocardial infarction, stent thrombosis and stroke.

RESULTS:

On pooled analysis, the risk of death (4.3% vs. 4.8%, odds ratio (OR) 0.90, 95% confidence interval (CI) 0.79-1.03; P=0.123), myocardial infarction (2.4% vs. 2.5%, OR 0.95, 95% CI 0.80-1.13; P=0.57) and stent thrombosis (1.3% vs. 1.6%, OR 0.80, 95% CI 0.63-1.01; P=0.066) was similar between thrombus aspiration plus primary percutaneous coronary intervention and primary percutaneous coronary intervention. The risk of stroke was higher in the thrombus aspiration plus primary percutaneous coronary intervention than the primary percutaneous coronary intervention group (0.84% vs. 0.59%, OR 1.401, 95% CI 1.004-1.954; P=0.047). However, on sensitivity analysis after removing the TOTAL trial, thrombus aspiration plus primary percutaneous coronary intervention was not associated with an increased risk of stroke (OR 1.01, 95% CI 0.58-1.78). The weak association between thrombus aspiration and stroke was also confirmed by the fact that the lower bound of the 95% CI was slightly below unity after removing either the study by Kaltoft or the ITTI trial. There was no interaction between the main study results and follow-up, evidence of coronary thrombus, or study sample size.

CONCLUSIONS:

In patients with ST-segment elevation myocardial infarction, thrombus aspiration plus primary percutaneous coronary intervention does not reduce the risk of death, myocardial infarction or stent thrombosis. Thrombus aspiration plus primary percutaneous coronary intervention is associated with an increased risk of stroke; however, this latter finding appears weak.

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.

Thrombus aspiration in patients with ST-elevation myocardial infarction: results of a national registry of interventional cardiology

Background

We aimed to evaluate the impact of thrombus aspiration (TA) during primary percutaneous coronary intervention (P-PCI) in ‘real-world’ settings.

Methods

We performed a retrospective study, using data from the National Registry of Interventional Cardiology (RNCI 2006–2012, Portugal) with ST-elevation myocardial infarction (STEMI) patients treated with P-PCI. The primary outcome, in-hospital mortality, was analysed through adjusted odds ratio (aOR) and 95% confidence intervals (95%CI).

Results

We assessed data for 9458 STEMI patients that undergone P-PCI (35% treated with TA). The risk of in-hospital mortality with TA (aOR 0.93, 95%CI:0.54–1.60) was not significantly decreased. After matching patients through the propensity score, TA reduced significantly the risk of in-hospital mortality (OR 0.58, 95%CI:0.35–0.98; 3500 patients).

Conclusions

The whole cohort data does not support the routine use of TA in P-PCI, but the results of the propensity-score matched cohort suggests that the use of selective TA may improve the short-term risks of STEMI.

The pathophysiology of acute myocardial infarction and strategies of protection beyond reperfusion: a continual challenge

The incidence of ST segment elevation myocardial infarction (STEMI) has decreased over the last two decades in developed countries, but mortality from STEMI despite widespread access to reperfusion therapy is still substantial as is the development of heart failure, particularly among an expanding older population. In developing countries, the incidence of STEMI is increasing and interventional reperfusion is often not available. We here review the pathophysiology of acute myocardial infarction and reperfusion, notably the temporal and spatial evolution of ischaemic and reperfusion injury, the different modes of cell death, and the resulting coronary microvascular dysfunction. We then go on to briefly characterize the cardioprotective phenomena of ischaemic preconditioning, ischaemic postconditioning, and remote ischaemic conditioning and their underlying signal transduction pathways. We discuss in detail the attempts to translate conditioning strategies and drug therapy into the clinical setting. Most attempts have failed so far to reduce infarct size and improve clinical outcomes in STEMI patients, and we discuss potential reasons for such failure. Currently, it appears that remote ischaemic conditioning and a few drugs (atrial natriuretic peptide, exenatide, metoprolol, and esmolol) reduce infarct size, but studies with clinical outcome as primary endpoint are still underway.

Emergency coronary angioplasty with stenting using Cordis® diagnostic coronary catheters when there is difficulty in engaging guide catheters and bench evaluation of diagnostic and guide catheters

INTRODUCTION AND AIMS

Difficulty in engaging with guide catheters is not uncommon in acute emergencies. We aimed to evaluate the use of Cordis^® INFINITI diagnostic catheters to perform angioplasty in patients in whom the coronaries cannot be engaged using standard guide catheters.

METHODS

In 34 cases of acute coronary syndrome, when difficulty in engagement with two standard guide catheters was encountered with reasonable manipulations, angioplasty was performed using diagnostic catheters. In total, 40 stents were placed by this technique. Pushability and trackability, distal tip flexion and three-point bending tests were performed to evaluate the performance of the guide and diagnostic catheters.

RESULTS

Angioplasty was performed easily in a setting where it would have been very difficult to perform. Coronary dissection occurred in one patient, treated by a stent. The stent and dilatation balloons were easily passed through the diagnostic catheters. Pressure tracings were clearly preserved with certain stent delivery systems, and at angioplasty, although there was slightly reduced opacification of the respective artery, the coronary anatomy was sufficiently visualized to perform angioplasty. No periprocedural target lesion complications were seen in any cases. Pushability and trackability tests showed good force transmission along a tortuous path with diagnostic catheters, and balanced force-displacement curves from three-point bending tests and distal tip softness tests.

CONCLUSION

Angioplasty with stenting can be performed safely through 6F Cordis^® infiniti diagnostic catheters when difficulty in engaging guide catheters is encountered.

[Management of high thrombus burden in primary PCI]

A large thrombus burden is not uncommon in primary percutaneous coronary intervention, and is associated with more frequent complications. The role of intracoronary thrombolysis and glycoprotein IIb/IIIa inhibitors in the management of a large thrombus burden is discussed. The use of thromboaspiration must follow a particular logic and used with rigorous manipulations; the capacities of the protective filters are often exceeded. Stents dedicated to thrombus management can be used. Interest and limits of these stents are developed. Direct stenting should be encouraged, and delayed stenting probably considered for the most important thrombotic burden despite "negative" results in studies.

Can thrombectomy and catheters used increase angiographically visible distal embolization in ST elevation myocardial infarction?

INTRODUCTION

Primary percutaneous coronary intervention (PPCI) is the preferred treatment of ST segment elevation myocardial infarction (STEMI). Manual thrombectomy catheters developed to prevent distant embolization are theoretically attractive; however, their clinical efficacy remains controversial. The effects of manual thrombectomy catheters on angiographically visible distal embolisation (AVDE) have not been studied so far. The aim of this study was to evaluate the effects of manual thrombectomy during PPCI on AVDE and to investigate whether there are differences in the incidence of AVDE according to the catheters used.

MATERIAL AND METHODS

Six hundred thirty-six consecutive patients undergoing primary PCI were included in the study between January 2010 and December 2012. Patients were divided into two groups: the PCI only group (465 patients) and the PCI plus manual thrombectomy group (171 patients).

RESULTS

Thrombus aspiration was associated with higher AVDE (13.55% vs. 26.9%, p = 0.0001), lower thrombolysis in myocardial infarction frame rate (2.49 ±0.86 vs. 2.79 ±0.57, p = 0.0001), lower myocardial blush grade (2.31 ±0.87 vs. 2.47 ±0.7, p = 0.016), lower ejection fraction (EF) (49.9 ±8.5 vs. 46.1 ±9.6, p = 0.0001) and higher maximal troponin release (15.7 ±16 vs. 9.4 ±11, p = 0.0001). No difference was observed in terms of mortality between the groups in follow-up (5.2% vs. 9.03%, p = 0.12). Angiographically visible distal embolisation was observed more frequently with Invatec catheters (p = 0.0001).

CONCLUSIONS

Angiographically visible distal embolisation during primary PCI occurs in a significant number of patients treated with manual thrombectomy. The results indicated that the incidence of AVDE may be different depending on the thrombectomy catheters used.

Mechanical strategies to enhance myocardial salvage during primary percutaneous coronary intervention in patients with STEMI

Primary percutaneous coronary intervention (PPCI) has become the mainstay of reperfusion therapy in patients with ST-segment elevation myocardial infarction (STEMI). Despite timely reperfusion by PPCI and restoration of epicardial blood flow in up to 95% of patients, tissue reperfusion remains suboptimal in a sizeable proportion of patients with STEMI. Over the years mechanical and pharmacological strategies to enhance myocardial salvage during PPCI have been developed and used in patients with STEMI. The most common mechanical strategies used in the setting of PPCI include: coronary stenting, direct stenting, mesh-covered stents, self-expanding stents, deferred stenting, thrombectomy, distal protection devices, intra-aortic balloon pumping, left ventricular assist devices and ischaemic conditioning. These strategies are thought to enhance myocardial salvage via improving acute procedural success, attenuation of distal embolisation, microvascular obstruction and reperfusion injury, and providing haemodynamic support. Coronary (direct) stenting is almost the default approach of reperfusion during PPCI procedures. Evidence on the use of mesh-covered stents, self-expanding stents, deferred stenting or left ventricular assist devices is scant and their use in the setting of PPCI remains limited. Mechanical thrombectomy, distal protection devices or routine intra-aortic balloon counterpulsation seem to offer no clinical benefit when used in the setting of PPCI. Although manual aspiration may improve indices of tissue reperfusion, recent research showed no clinical benefit of routine use of this strategy in patients with STEMI undergoing PPCI. Ischaemic conditioning, although promising, remains at an investigational stage and needs further research.

Variable methodological quality and use found in systematic reviews referenced in STEMI clinical practice guidelines

BACKGROUND

The objective of this study was to assess the methodological quality and clarity of reporting of the systematic reviews (SRs) supporting clinical practice guideline (CPG) recommendations in the management of ST-elevation myocardial infarction (STEMI) across international CPGs.

METHODS

We searched 13 guideline clearinghouses including the National Guideline Clearinghouse and Guidelines International Network (GIN). To meet inclusion criteria CPGs must be pertinent to the management of STEMI, endorsed by a governing body or national organization, and written in English. We retrieved SRs from the reference sections using a combination of keywords and hand searching. Two investigators scored eligible SRs using AMSTAR and PRISMA.

RESULTS

We included four CPGs. We extracted 71 unique SRs. These SRs received AMSTAR scores ranging from 1 (low) to 9 (high) on an 11-point scale. All CPGs consistently underperformed in areas including disclosure of funding sources, risk of bias, and publication bias according to AMSTAR. PRISMA checklist completeness ranged from 44% to 96%. The PRISMA scores indicated that SRs did not provide a full search strategy, study protocol and registration, assessment of publication bias or report funding sources. Only one SR was referenced in all four CPGs. All CPGs omitted a large subset of available SRs cited by other guidelines.

CONCLUSIONS

Our study demonstrates the variable quality of SRs used to establish recommendations within guidelines included in our sample. Although guideline developers have acknowledged this variability, it remains a significant finding that needs to be addressed further.

FUNDING

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Long-term outcomes with aspiration thrombectomy for patients undergoing primary percutaneous coronary intervention: A meta-analysis of randomized trials

Randomized clinical trials that examined long-term clinical outcomes of routine aspiration thrombectomy prior to primary percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction have yielded different results. We hypothesized that the routine use of manual thrombus aspiration prior to primary PCI lacks long-term clinical benefits. Electronic databases were searched for randomized trials comparing routine aspiration thrombectomy and conventional PCI. We included only trials that reported clinical outcomes beyond 6 months. The primary outcome was all-cause mortality, and the secondary outcomes included major adverse cardiovascular events, re-infarction, cardiovascular mortality, and stent thrombosis (ST). A DerSimonian-Laird model was used to construct the summary estimates risk ratio (RR). We retrieved 18 trials with 20 641 ST-segment elevation myocardial infarction patients, of whom 10 331 patients underwent routine aspiration thrombectomy prior to primary PCI. At a mean follow-up of 12 months, there was no significant decrease in the risk of all-cause mortality (RR: 0.93, 95% confidence interval [CI]: 0.82-1.05, P = 0.22), major adverse cardiac events (RR: 0.95, 95% CI: 0.87-1.03, P = 0.18), re-infarction (RR: 0.95, 95% CI: 0.80-1.13, P = 0.59), cardiovascular mortality (RR: 0.80, 95% CI: 0.47-1.36, P = 0.40), or ST (RR: 0.80, 95% CI: 0.63-1.01, P = 0.06) with routine aspiration thrombectomy. Routine aspiration thrombectomy prior to primary PCI was not associated with a reduction in long-term mortality or clinical outcomes. Future randomized trials are warranted to further evaluate the role of aspiration thrombectomy in select patients and coronary lesions.

A mechanism for stroke complicating thrombus aspiration

We propose a mechanism of how stroke may be caused by thrombus aspiration during primary percutaneous coronary intervention (PPCI), and how it may be technique-dependent. Two recent meta-analyses report increased risk of stroke in patients undergoing routine thrombus aspiration during STEMI and the value of this technique has been controversial. The mechanism of stroke has not been fully explained. This case demonstrates 2 mechanisms by which aspiration might cause thrombus embolization. We recommend that if thrombus aspiration is performed during PPCI for STEMI, it should be done selectively and carefully. It is prudent to make sure the guide catheter tip is not free in the aorta when the aspiration catheter is withdrawn, to maintain suction on the aspiration catheter as it is withdrawn (particularly if the aspiration port seems to be obstructed), and to aspirate the guide catheter after the aspiration catheter is removed to capture any fragments of thrombus that remain in the guide catheter. © 2016 Wiley Periodicals, Inc.

Meta-Analysis of the Long-Term Effect of Routine Aspiration Thrombectomy in Patients Undergoing Primary Percutaneous Coronary Intervention

American College of Cardiology Foundation/American Heart Association guidelines no longer recommend the use of routine aspiration thrombectomy during primary percutaneous coronary intervention (PCI). This is based on evidence from recent randomized controlled trials (RCTs) that suggests that the long-term benefits of aspiration thrombectomy were previously overestimated. We conducted a systematic review and meta-analysis of RCTs to examine the effect of routine aspiration thrombectomy during primary PCI versus primary PCI alone on markers of reperfusion immediately after PCI and on clinical outcomes at ≥6 months. We systematically searched Medline, EMBASE, and the Cochrane Library of Clinical trials for RCTs published in English or French with follow-up ≥6 months. Data were pooled using random-effects models. Eighteen publications (containing data from 14 RCTs, n = 20,285) met our inclusion criteria. Aspiration thrombectomy was associated with higher rates of ST-segment resolution (relative risk [RR] 1.22, 95% CI 1.07 to 1.40) and myocardial blush grade 3 (RR 1.30, 95% CI 1.01 to 1.67) and a reduced risk of no reflow immediately after PCI (RR 0.63, 95% CI 0.40 to 0.98). However, thrombectomy was not associated with our primary outcome of all-cause mortality at longest available follow-up (RR 0.92, 95% CI 0.81 to 1.04). Similar results were obtained for myocardial infarction and target vessel/lesion revascularization. Thrombectomy also increased the risk of stroke (RR 1.59, 95% CI 1.07 to 2.35). In conclusion, routine aspiration thrombectomy during primary PCI has some short-term clinical benefits but does not improve outcomes ≥6 months and increases the risk of stroke.

No reflow phenomenon in percutaneous coronary interventions in ST-segment elevation myocardial infarction

Percutaneous coronary intervention (PCI) is effective in opening the infarct related artery and restoring thrombolysis in myocardial infarction flow 3 (TIMI-flow 3) in large majority of ST-elevation myocardial infarction (STEMI). However there remain a small but significant proportion of patients, who continue to manifest diminished myocardial reperfusion despite successful opening of the obstructed epicardial artery. This phenomenon is called no-reflow. Clinically it manifests with recurrence of chest pain and dyspnea and may progress to cardiogenic shock, cardiac arrest, serious arrhythmias and acute heart failure. No reflow is regarded as independent predictor of death or recurrent myocardial infarction. No reflow is a multi-factorial phenomenon. However micro embolization of atherothrombotic debris during PCI remains the principal mechanism responsible for microvascular obstruction. This review summarizes the pathogenesis, diagnostic methods and the results of various recent randomized trials and studies on the prevention and management of no-reflow.

Aspiration thrombectomy prior to percutaneous coronary intervention in ST-elevation myocardial infarction: a systematic review and meta-analysis

BACKGROUND

Trials of aspiration thrombectomy (AT) prior to primary percutaneous intervention (PCI) in patients with ST-segment elevation MI (STEMI) have shown apparently inconsistent results and therefore generated uncertainty and controversy. To summarize the effects of AT prior to PCI versus conventional PCI in STEMI patients.

METHODS

Searches of MEDLINE, EMBASE and CENTRAL to June 2015 and review of reference lists of previous reviews. We included randomized controlled trials (RCTs) comparing AT prior to PCI with conventional PCI alone. Pairs of reviewers independently screened eligible articles; extracted data; and assessed risk of bias. We used the GRADE approach to rate overall certainty of the evidence.

RESULTS

Among 73 potential articles identified, 20 trials including 21,660 patients were eligible; data were complete for 20,866 patients. Moderate-certainty evidence suggested a non statistically significant decrease in overall mortality (risk ratio (RR) 0.89, 95 % confidence interval, 0.78 to 1.01, risk difference (RD) 4/1,000 over 6 months), no impact on recurrent MI (RR 0.94, 95 % CI, 0.79 to 1.12) or major bleeding (RR 1.02, 95 % CI, 0.78 to 1.35), and an increase in stroke (RR 1.56, 95 % CI, 1.09 to 2.24, RD 3/1,000 over 6 months).

CONCLUSIONS

Moderate certainty evidence suggests aspiration thrombectomy is associated with a possible small decrease in mortality (4 less deaths/1000 over 6 months) and a small increase in stroke (3 more strokes/1000 over 6 months). Because absolute effects are very small and closely balanced, thrombectomy prior to primary PCI should not be used as a routine strategy.

Mechanical thrombectomy using the Solitaire stent in a left main coronary artery: A novel approach to coronary thrombus retrieval

The Solitaire stent is a self-expanding nitinol, fully retrievable stent that was originally designed for applications in cerebral circulation. Expanded indications for its use in mechanical embolectomy during acute ischemic stroke have proven safe and effective. Herein, we describe a novel use of this stent to perform a mechanical thrombectomy of a large left main coronary artery thrombus. © 2016 Wiley Periodicals, Inc.

Is Aspiration Thrombectomy Beneficial in Patients Undergoing Primary Percutaneous Coronary Intervention? Meta-Analysis of Randomized Trials

BACKGROUND

It is unclear whether intravenous glycoprotein IIb/IIIa inhibitors or ischemic time might modify any clinical benefits observed with aspiration thrombectomy before primary percutaneous coronary intervention (PCI) in patients with ST-segment-elevation myocardial infarction.

METHODS AND RESULTS

Electronic databases were searched for trials that randomized ST-segment-elevation myocardial infarction patients to aspiration thrombectomy before PCI versus conventional PCI. Summary estimates were constructed using a DerSimonian-Laird model. Seventeen trials with 20 960 patients were available for analysis. When compared with conventional PCI, aspiration thrombectomy was not associated with a significant reduction in the risk of mortality 2.8% versus 3.2% (risk ratio [RR], 0.89; 95% confidence interval [CI], 0.76-1.04; P=0.13), reinfarction 1.3% versus 1.4% (RR, 0.93; 95% CI, 0.73-1.17; P=0.52), the combined outcome of mortality or reinfarction 4.1% versus 4.6% (RR, 0.90; 95% CI, 0.79-1.02; P=0.11), or stent thrombosis 0.9% versus 1.2% (RR, 0.82; 95% CI, 0.62-1.08; P=0.15). Aspiration thrombectomy was associated with a nonsignificant increase in the risk of stroke 0.6% versus 0.4% (RR, 1.45; 95% CI, 0.96-2.21; P=0.08). Meta-regression analysis did not identify a difference for the log RR of mortality, reinfarction, and the combined outcome of mortality or reinfarction with intravenous glycoprotein IIb/IIIa inhibitors (P=0.17, 0.70, and 0.50, respectively) or with ischemic time (P=0.29, 0.66, and 0.58, respectively).

CONCLUSIONS

Aspiration thrombectomy before primary PCI is not associated with any benefit on clinical end points and might increase the risk of stroke. Concomitant administration of intravenous glycoprotein IIb/IIIa inhibitors and ischemic time did not seem to influence any potential benefits observed with aspiration thrombectomy.

Impact of thrombus aspiration during ST-Elevation Myocardial Infarction: a six month composite endpoint and risk of stroke analyses of the TASTE trial

BACKGROUND

Routine thrombus aspiration during primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI) did not reduce the primary composite endpoint in the "A Randomised Trial of Routine Aspiration ThrOmbecTomy With PCI Versus PCI ALone in Patients With STEMI Undergoing Primary PCI" (TOTAL) trial. We aimed to analyse a similar endpoint in "The Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia" (TASTE) trial up to 180 days.

METHODS

In TASTE, 7244 patients with STEMI were randomised to thrombus aspiration followed by PCI or to PCI alone. We analysed the quadruple composite endpoint of cardiovascular death, cardiogenic shock, rehospitalisation for myocardial infarction, or new hospitalisation for heart failure. Furthermore, an extended net-benefit composite endpoint including stent thrombosis, target vessel revascularization or stroke within 180 days was analysed.

RESULTS

The primary quadruple composite endpoint occurred in 8.7 % (316 of 3621) in the thrombus aspiration group compared to 9.3 % (338 of 3623) in the PCI alone group (hazard ratio (HR), 0.93; 95 % confidence interval (CI); 0.80 - 1.09, P = 0.36) and the extended net-benefit composite endpoint in 12.0 % (436) vs. 13.2 % (479) (HR, 0.90; 95 % CI; 0.79 - 1.03, P = 0.12). Stroke within 30 days occurred in 0.7 % (27) vs. 0.7 % (24) (HR, 0.89; 95 % CI; 0.51-1.54, P = 0.68).

CONCLUSIONS

A large and an extended composite endpoint analysis from the TASTE trial did not demonstrate any clinical benefit of routine thrombus aspiration during PCI in patients with STEMI. There was no evidence of an increased risk of stroke with thrombus aspiration.