Impact of intracoronary aspiration thrombectomy during primary angioplasty on left ventricular remodelling in patients with anterior ST elevation myocardial infarction

Cardiac death and reinfarction after 1 year in the Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS): a 1-year follow-up study

BACKGROUND

Percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction can be complicated by spontaneous or angioplasty-induced embolisation of atherothrombotic material. Distal blockage induces microvascular obstruction and can result in less than optimum reperfusion of viable myocardium. The Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS) found that thrombus aspiration resulted in improved myocardial reperfusion compared with conventional PCI, but whether this benefit improves clinical outcome is unknown. We aimed to investigate whether the early efficacy of thrombus aspiration seen in TAPAS translated into clinical benefit after 1 year.

METHODS

Patients with ST-elevation myocardial infarction enrolled at the University Medical Centre Groningen were randomly assigned in a 1:1 ratio to either thrombus aspiration or conventional treatment, before undergoing initial coronary angiography. Exclusion criteria were rescue PCI after thrombolysis and known existence of a concomitant disease with life expectancy less than 6 months. Of the 1071 patients enrolled between January, 2005, and December, 2006, vital status at or beyond 1 year after randomisation was available for 1060 (99%). The primary endpoint was cardiac death or non-fatal reinfarction after 1 year, and analysis was by intention to treat. The TAPAS trial is registered with Current Controlled Trials number ISRCTN16716833.

FINDINGS

Cardiac death at 1 year was 3.6% (19 of 535 patients) in the thrombus aspiration group and 6.7% (36 of 536) in the conventional PCI group (hazard ratio [HR] 1.93; 95% CI 1.11-3.37; p=0.020). 1-year cardiac death or non-fatal reinfarction occurred in 5.6% (30 of 535) of patients in the thrombus aspiration group and 9.9% (53 of 536) of patients in the conventional PCI group (HR 1.81; 95% CI 1.16-2.84; p=0.009).

INTERPRETATION

Compared with conventional PCI, thrombus aspiration before stenting of the infarcted artery seems to improve the 1-year clinical outcome after PCI for ST-elevation myocardial infarction.

Percutaneous coronary intervention and the no-reflow phenomenon

No-reflow during percutaneous coronary intervention (PCI) is observed most commonly during saphenous vein graft intervention, rotational atherectomy and primary PCI for acute ST-elevation myocardial infarction. The contributions of distal embolization and ischemia/reperfusion injury to the pathogenesis of no-reflow vary in these settings, as does prevention and management. Prevention of no-reflow in these high-risk groups is the best treatment strategy, employing antiplatelet agents, vasodilators and/or mechanical devices to prevent distal embolization. Once mechanical factors are excluded as a cause for reduced epicardial flow, the treatment of established no-reflow is mainly pharmacologic, since the obstruction occurs at the level of the microvasculature. Compared with patients in whom no-reflow is transient, refractory no-reflow is associated with a markedly increased risk of 30-day mortality.

Angiographic stent thrombosis after routine use of drug-eluting stents in ST-segment elevation myocardial infarction: the importance of thrombus burden

OBJECTIVES

This study sought to investigate the impact of thrombus burden on the clinical outcome and angiographic infarct-related artery stent thrombosis (IRA-ST) in patients routinely treated with drug-eluting stent (DES) implantation for ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

There are limited data for the safety and effectiveness of DES in STEMI.

METHODS

We retrospectively analyzed 812 consecutive patients treated with DES implantation for STEMI. Intracoronary thrombus burden was angiographically estimated and categorized as large thrombus burden (LTB), defined as thrombus burden > or =2 vessel diameters, and small thrombus burden (STB) to predict clinical outcomes. Major adverse cardiac events (MACE) were defined as death, repeat myocardial infarction, and IRA reintervention.

RESULTS

Mean duration of follow-up was 18.2 +/- 7.8 months. Large thrombus burden was an independent predictor of mortality (hazard ratio [HR] 1.76, p = 0.023) and MACE (HR 1.88, p = 0.001). The cumulative angiographic IRA-ST was 1.1% at 30 days and 3.2% at 2 years, and continued to augment beyond 2 years. It was significantly higher in the LTB compared with the STB group (8.2% vs. 1.3% at 2 years, respectively, p < 0.001). Significant independent predictors for IRA-ST were LTB (HR 8.73, p < 0.001), stent thrombosis at presentation (HR 6.24, p = 0.001), bifurcation stenting (HR 4.06, p = 0.002), age (HR 0.55, p = 0.003), and rheolytic thrombectomy (HR 0.11, p = 0.03).

CONCLUSIONS

Large thrombus burden is an independent predictor of MACE and IRA-ST in patients treated with DES for STEMI.

Adjunctive devices in primary or rescue PCI: a meta-analysis of randomized trials

OBJECTIVES

To overview and summarize the results emerging from the studies on adjunctive devices (AD) with theoretical anti-embolic properties in patients with ST-elevation acute myocardial infarction (STEMI) undergoing percutaneous coronary interventions (PCI).

BACKGROUND

A series of small-to-medium size randomized studies have compared different AD with standard PCI (SP) in the setting of STEMI. The reported results are conflicting.

METHODS

Eighteen prospective randomized studies on 3180 STEMI patients comparing AD with SP were identified and entered the meta-analysis. Pre-specified angiographic, electrocardiographic (absence of ST-segment resolution, STR) and early (up to 30 days) clinical end-points were assessed.

RESULTS

AD were associated with lower rates of angiographically evident distal embolization: OR (95% CI): 0.54 (0.37-0.81). Analyses of angiographic and electrocardiographic reperfusion showed striking heterogeneity among studies and an overall trend toward better results with AD: OR (95% CI) 0.76 (95% CI 0.51-1.12) for TIMI<3, 0.53 (0.37-0.76) for myocardial blush grade (MBG)<3, 0.60 (0.45-0.78) for absence of STR. Subgroup analysis according to the type of AD for the end-point of no STR showed concordant absence of benefit in studies testing distal protection devices, positive results being confined to the studies using thrombectomy devices (OR 0.46, 95% CI 0.32-0.66). However, the possibility of a "small study" bias within thrombectomy studies cannot be discharged (significant heterogeneity and positive Egger's test). Early major adverse cardiac events were not different between AD and SP.

CONCLUSIONS

AD use may be associated with reduced rate of angiographic distal embolization, and improved MBG 3 and STR rates. However, efficacy might vary with the type of device employed. Moreover, early clinical outcome is not modified suggesting that further, larger, studies are needed to assess the clinical impact of AD.

CONDENSED ABSTRACT

We conducted a meta-analysis of 18 prospective randomized trials comparing adjunctive devices (AD) with standard PCI in the setting of STEMI. The use of AD was associated with lower rates of (angiographically evident) distal embolization. Analyses of angiographic and electrocardiographic reperfusion showed striking heterogeneity and an overall trend toward better results with AD. Subgroup analysis suggested that different types of device may have different effects. Early major adverse cardiac events were similar between AD and SP.

Adjunctive mechanical devices to prevent distal embolization in patients undergoing mechanical revascularization for acute myocardial infarction: a meta-analysis of randomized trials

BACKGROUND

The benefits of adjunctive mechanical devices to prevent distal embolization in patients with acute myocardial infarction (AMI) are still a matter of debate. The aim of this meta-analysis was to combine data from all randomized trials conducted with adjunctive mechanical devices to prevent distal embolization in AMI.

METHODS

The literature was scanned by formal searches of electronic databases (MEDLINE and Central) from January 1990 to October 2006, scientific session abstracts (from January 1990 to October 2006), and oral presentation and/or expert slide presentations (from January 2002 to October 2006) (on the Transcatheter Cardiovascular Therapeutics, American Heart Association, European Society of Cardiology, American College of Cardiology, and European Percutaneous Revascularization Web sites). We examined all randomized trials on adjunctive mechanical devices to prevent distal embolization in AMI. The following key words were used: randomized trial, myocardial infarction, reperfusion, primary angioplasty, rescue angioplasty, thrombectomy, thrombus aspiration, proximal or distal protection device, X-sizer, Diver, Export Catheter, Angiojet, Rescue catheter, Pronto catheter, PercuSurge, GuardWire, FilterWire, and SpideRX. Disagreements were resolved by consensus.

RESULTS

A total of 21 trials with 3721 patients were included (1877 patients [50.4%] in the adjunctive mechanical device group and 1844 [49.6%] in the control group); 1502 patients (40.3%) were randomized in trials with distal protection devices, and 2219 patients (59.7%) were randomized in trials with thrombectomy devices. Adjunctive mechanical devices were associated with a higher rate of postprocedural TIMI 3 flow (89.4% vs 87.1%, P = .03), a significantly higher rate of postprocedural myocardial blush grade 3 (48.8% vs 36.5%, P < .0001), and less distal embolization (6.0% vs 9.3%, P = .008), without any benefit in terms of 30-day mortality (2.5% vs 2.6%, P = .88). No difference was observed in terms of coronary perforations (0.27% vs 0.07%, P = .24).

CONCLUSIONS

This meta-analysis demonstrates that, among patients with AMI treated with percutaneous coronary intervention, the use of adjunctive mechanical devices to prevent distal embolization is associated with better myocardial perfusion and less distal embolization, but without an apparent improvement in survival.

Thrombus Aspiration Reduces Microvascular Obstruction After Primary Coronary Intervention

OBJECTIVES

The aim of this study was to clarify the role of microembolization in the genesis of microvascular obstruction (MO) after percutaneous coronary intervention (PCI).

BACKGROUND

Fifty consecutive patients entered the myocardial contrast echocardiography (MCE) substudy of the REMEDIA (Randomized Evaluation of the Effect of Mechanical Reduction of Distal Embolization by Thrombus Aspiration in Primary and Rescue Angioplasty) trial, which defined the role of a new thrombus-aspirating device in preventing distal microembolization after PCI.

METHODS

A total of 25 patients were randomized to be pretreated with thrombus aspiration before PCI of the culprit lesion and 25 received standard PCI. At 24 h, 1 week, and 6 months after PCI, MCE was performed by Sonovue, and real-time imaging was performed by contrast pulse sequencing technology. Regional wall motion score index (WMSI), contrast score index (CSI), endocardial length of wall motion abnormality (WML) and contrast defect (CDL), end-diastolic and end-systolic left ventricular (LV) volumes, and ejection fraction were calculated.

RESULTS

At each time point, in patients treated with a thrombus-aspiration filter device, WMSI, CSI, WML, and CDL were significantly lower and ejection fraction higher (p < 0.05 vs. control patients), whereas LV volumes were slightly but not significantly smaller compared with control patients. In the overall study population, the extent of MO significantly correlated with temporal changes in LV volumes.

CONCLUSIONS

Thrombus aspiration used at the time of PCI significantly reduces the extent of MO and myocardial dysfunction, although it does not have a significant favorable effect in preventing LV remodeling. Thus, the beneficial effect of thrombus aspiration occurs at the microvascular level, but additional mechanisms may play a role in influencing the final extent of MO, which strictly correlates with post-infarct LV remodeling.

Aspiration thrombectomy and primary percutaneous coronary intervention

How beneficial is the adjunctive use of thrombectomy devices in STEMI patients undergoing primary angioplasty?