Impact of thrombus aspiration during primary percutaneous coronary intervention in cardiogenic shock complicating ST-segment elevation myocardial infarction

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).

The REFLO-STEMI trial comparing intracoronary adenosine, sodium nitroprusside and standard therapy for the attenuation of infarct size and microvascular obstruction during primary percutaneous coronary intervention: study protocol for a randomised controlled trial

BACKGROUND

Microvascular obstruction (MVO) secondary to ischaemic-reperfusion injury is an important but underappreciated determinant of short- and longer-term outcome following percutaneous coronary intervention (PCI) treatment of ST-elevation myocardial infarction (STEMI). Several small studies have demonstrated a reduction in the degree of MVO utilising a variety of vasoactive agents, with adenosine and sodium nitroprusside (SNP) being most evaluated. However, the evidence base remains weak as the trials have had variable endpoints, differing drug doses and delivery. As such, the results regarding benefit are conflicting.

METHODS

The REperfusion Facilitated by LOcal adjunctive therapy in STEMI (REFLO-STEMI) trial is a multicentre, prospective, randomised, controlled, open label, study with blinded endpoint analysis: Patients presenting within 6 h of onset of STEMI and undergoing planned primary PCI (P-PCI) with TIMI 0/1 flow in the infarct-related artery (IRA) and no significant bystander coronary artery disease on angiography, are randomised into one of three groups: PCI with adjunctive pharmacotherapy (intracoronary adenosine or SNP) or control (standard PCI). All receive Bivalirudin anticoagulation and thrombus aspiration. The primary outcome is infarct size (IS) (determined as a percentage of total left ventricular mass) measured by cardiac magnetic resonance imaging (CMRI) undertaken at 48 to 72 h post P-PCI. Secondary outcome measures include MVO (hypoenhancement within infarct core) on CMRI, angiographic markers of microvascular perfusion and MACE during 1-month follow-up. The study aims to recruit 240 patients (powered at 80% to detect a 5% absolute reduction in IS).

DISCUSSION

The REFLO-STEMI study has been designed to address the weaknesses of previous trials, which have collectively failed to demonstrate whether adjunctive pharmacotherapy with adenosine and/or SNP can reduce measures of myocardial injury (infarct size and MVO) and improve clinical outcome, despite good basic evidence that they have the potential to attenuate this process. The REFLO-STEMI study will be the most scientifically robust trial to date evaluating whether adjunctive therapy (intracoronary adenosine or SNP following thrombus aspiration) reduces CMRI measured IS and MVO in patients undergoing P-PCI within 6 h of onset of STEMI.

TRIAL REGISTRATION

Trial registered 20th November 2012: ClinicalTrials.gov Identifier NCT01747174.