Intracoronary Thrombolysis in Patients With ST-Segment Elevation Myocardial Infarction: A Meta-Analysis of Randomized Controlled Trials

Intracoronary Thrombolysis in ST-Segment Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention: an Updated Meta-analysis of Randomized Controlled Trials

BACKGROUND

Primary percutaneous coronary intervention (PPCI) is the standard reperfusion treatment in ST-segment elevation myocardial infarction (STEMI). Intracoronary thrombolysis (ICT) may reduce thrombotic burden in the infarct-related artery, which is often responsible for microvascular obstruction and no-reflow.

METHODS

We conducted, according to the PRISMA statement, the largest meta-analysis to date of ICT as adjuvant therapy to PPCI. All relevant studies were identified by searching the PubMed, Scopus, Cochrane Library, and Web of Science.

RESULTS

Thirteen randomized controlled trials (RCTs) involving a total of 1876 patients were included. Compared to the control group, STEMI ICT-treated patients had fewer major adverse cardiac events (MACE) (OR 0.65, 95% CI, 0.48-0.86, P = 0.003) and an improved 6-month left ventricular ejection fraction (MD 3.78, 95% CI, 1.53-6.02, P = 0.0010). Indices of enhanced myocardial microcirculation were better with ICT (Post-PCI corrected thrombolysis in myocardial infarction (TIMI) frame count (MD - 3.57; 95% CI, - 5.00 to - 2.14, P < 0.00001); myocardial blush grade (MBG) 2/3 (OR 1.76; 95% CI, 1.16-2.69, P = 0.008), and complete ST-segment resolution (OR 1.97; 95% CI, 1.33-2.91, P = 0.0007)). The odds for major bleeding were comparable between the 2 groups (OR 1.27; 95% CI, 0.61-2.63, P = 0.53).

CONCLUSIONS

The present meta-analysis suggests that ICT was associated with improved MACE and myocardial microcirculation in STEMI patients undergoing PPCI, without significant increase in major bleeding. However, these findings necessitate confirmation in a contemporary large RCT.

Intracoronary antithrombotic therapy during primary percutaneous coronary intervention in patients with STEMI: A systematic review and network meta-analysis

INTRODUCTION

The efficacy of intracoronary (IC) antithrombotic therapy, which may best prevent the no-reflow phenomenon during percutaneous coronary intervention (PCI), remains unclear. Therefore, we compared the efficacy and safety of different IC antithrombotic agents.

MATERIALS AND METHODS

This systematic review and network meta-analysis of randomized controlled trials (RCTs) compared IC fibrinolytic agents (recombinant tissue plasminogen activators [rtPAs] and non-rtPAs) or glycoprotein IIb/IIIa inhibitors (small molecules and monoclonal antibodies) with placebo by searching the relevant studies published before September 21, 2022. Bayesian network meta-analyses were performed using random-effects models.

RESULTS

Twenty-five RCTs with 4546 patients were included. Non-rtPAs and small molecules were significantly more effective in achieving thrombolysis in myocardial infarction (TIMI) grade 3 flow than placebo (odds ratio [OR] 2.28, 95 % credible intervals [CrI] 1.24-4.13; OR 2.06, 95 % CrI 1.17-3.46). Moreover, these agents' efficacy was observed in other microcirculation-related outcomes, including TIMI myocardial perfusion grade 3, complete ST-segment resolution, and corrected TIMI frame counts. Within 6 months, small molecules were associated with both an improved left ventricular ejection fraction (MD 3.90, 95 % CrI 0.48-7.46) and major adverse cardiac events (MACE) reduction (OR 0.36, 95 % CrI 0.20-0.61). Non-rtPAs demonstrated a reduced MACE incidence within 6 months (OR 0.51, 95 % CrI 0.31-0.81). The results were consistent in the subgroup with a total ischemic time > 6 h. No significant differences in mortality or bleeding events were observed.

CONCLUSIONS

IC non-rtPAs and small molecules may be effective for adjunctive therapy to PCI, particularly in patients with longer ischemia periods.

Safety and efficacy of intracoronary thrombolytic agents during primary percutaneous coronary intervention for STEMI

INTRODUCTION

Large thrombus burden in patients with ST elevation myocardial infarction (STEMI) is associated with higher rates of distal embolization, no-reflow phenomenon, abrupt closure, stent thrombosis, major adverse cardiovascular events (MACE), and mortality. Intracoronary (IC) thrombolytic agents are theoretically attractive as an adjunct to primary percutaneous coronary intervention (PPCI) as they activate endogenous fibrinolysis which results in degradation of the cross-linked fibrin matrix in coronary thrombus.

AREAS COVERED

We reviewed published studies reporting on intraprocedural anti-thrombus strategies used during PPCI including randomized controlled trials and observational studies.

EXPERT OPINION

Published studies are limited by small sample size and heterogeneity due to variation in indication, inclusion criteria, thrombolytic agent, dose, delivery mechanisms, antiplatelet and anticoagulant regimen, timing in regard to reperfusion, PCI techniques, and endpoints. Despite these limitations, data are consistent that IC administration of thrombolytic agents at low doses is associated with low rates of bleeding and vascular complications. While there is currently no compelling data demonstrating a benefit to the routine use of IC thrombolytic therapy in patients with STEMI, there is suggestive data that IC thrombolysis may have benefit in selected patients.

Coronary microvascular dysfunction: A review of recent progress and clinical implications

The coronary microcirculation plays a cardinal role in regulating coronary blood flow to meet the changing metabolic demands of the myocardium. Coronary microvascular dysfunction (CMD) refers to structural and functional remodeling of the coronary microcirculation. CMD plays a role in the pathogenesis of obstructive and non-obstructive coronary syndromes as well as myocardial diseases, including heart failure with preserved ejection fraction (HFpEF). Despite recent diagnostic advancements, CMD is often under-appreciated in clinical practice, and may allow for the development of novel therapeutic targets. This review explores the diagnosis and pathogenic role of CMD across a range of cardiovascular diseases, its prognostic significance, and the current therapeutic landscape.

Has low-dose intracoronary thrombolysis gained ground in primary percutaneous intervention?

Reducing thrombus burden would improve patient's outcomes. Low-dose intracoronary thrombolytic agent administration has been considered to improve myocardial microcirculation, cardiac function, and major adverse cardiovascular events in patients presenting with ST-segment elevation myocardial infarction and high thrombus burden. This paper discusses published meta-analyses on intracoronary thrombolysis in primary percutaneous intervention.

“No-Reflow” Phenomenon: A Contemporary Review

Primary percutaneous angioplasty (pPCI), represents the reperfusion strategy of choice for patients with STEMI according to current international guidelines of the European Society of Cardiology. Coronary no-reflow is characterized by angiographic evidence of slow or no anterograde epicardial flow, resulting in inadequate myocardial perfusion in the absence of evidence of mechanical vessel obstruction. No reflow (NR) is related to a functional and structural alteration of the coronary microcirculation and we can list four main pathophysiological mechanisms: distal atherothrombotic embolization, ischemic damage, reperfusion injury, and individual susceptibility to microvascular damage. This review will provide a contemporary overview of the pathogenesis, diagnosis, and treatment of NR.