Assessment of the Safety and Efficacy of a New Treatment Strategy with Percutaneous Coronary Intervention (ASSENT-4 PCI) investigators. Primary versus tenecteplase-facilitated percutaneous coronary intervention in patients with ST-segment elevation acute myocardial infarction (ASSENT-4 PCI): randomised trial

Restoring microvascular circulation with diagnostic ultrasound and contrast agent: rationale and design of the REDUCE trial

OBJECTIVES

This study aims to evaluate the efficacy and cost-effectiveness of sonothrombolysis delivered pre and post primary percutaneous coronary intervention (pPCI) on infarct size assessed by cardiac MRI, in patients presenting with STEMI, when compared against sham procedure.

BACKGROUND

More than a half of patients with successful pPCI have significant microvascular obstruction and residual infarction. Sonothrombolysis is a therapeutic use of ultrasound with contrast enhancement that may improve microcirculation and infarct size. The benefits and real time physiological effects of sonothrombolysis in a multicentre setting are unclear.

METHODS

The REDUCE (Restoring microvascular circulation with diagnostic ultrasound and contrast agent) trial is a prospective, multicentre, patient and outcome blinded, sham-controlled trial. Patients presenting with STEMI will be randomized to one of 2 treatment arms, to receive either sonothrombolysis treatment or sham echocardiography before and after pPCI. This tailored design is based on preliminary pilot data from our centre, showing that sonothrombolysis can be safely delivered, without prolonging door to balloon time. Our primary endpoint will be infarct size assessed on day 4±2 on Cardiac Magnetic Resonance (CMR). Patients will be followed up for 6 months post pPCI to assess secondary endpoints. Sample size calculations indicate we will need 150 patients recruited in total.

CONCLUSIONS

This multicentre trial will test whether sonothrombolysis delivered pre and post primary PCI can improve patient outcomes and is cost-effective, when compared with sham ultrasound delivered with primary PCI. The results from this trial may provide evidence for the utilization of sonothrombolysis as an adjunct therapy to pPCI to improve cardiovascular outcomes in STEMI. ANZ Clinical Trial Registration number: ACTRN 12620000807954.

Emodin in-situ delivery with Pluronic F-127 hydrogel for myocardial infarction treatment: Enhancing efficacy and reducing hepatotoxicity

AIMS

This study evaluates the therapeutic potential of emodin in enhancing the anti-inflammatory phenotype of macrophages, proposing a novel treatment strategy for myocardial infarction (MI). Our objective is to overcome the challenge of myocardial repair post-MI by developing an innovative in-situ myocardial drug delivery system that reduces associated hepatotoxicity.

MATERIALS AND METHODS

Through network pharmacology, it was identified that emodin primarily treats MI through anti-inflammatory actions. We investigated the influence of emodin on macrophage polarization using cellular assays and examined its therapeutic impacts and hepatotoxicity in animal models across various doses. A novel in-situ drug delivery system was devised using Pluronic F-127, a thermosensitive hydrogel, to enhance solubility and enable localized delivery to the myocardium.

KEY FINDINGS

In vitro studies confirmed that emodin effectively induces macrophage polarization toward an anti-inflammatory phenotype. In vivo analyses demonstrated a dose-dependent therapeutic effect on the myocardium, although higher doses led to significant hepatotoxicity. The innovative drug delivery system increased emodin's solubility, facilitated precise myocardial targeting, and markedly reduced systemic exposure and liver toxicity.

SIGNIFICANCE

This study introduces an advanced approach to treating MI by leveraging the natural anti-inflammatory properties of emodin combined with drug delivery technology. This strategy not only enhances the clinical feasibility of emodin for MI treatment but also represents a significant advancement in therapeutic methods. It focuses on increasing the drug concentration in the myocardium while minimizing the systemic side effects of the drug.

Intracoronary thrombolysis in ST-elevation myocardial infarction: a systematic review and meta-analysis

BACKGROUND

Despite restoration of epicardial blood flow in acute ST-elevation myocardial infarction (STEMI), inadequate microcirculatory perfusion is common and portends a poor prognosis. Intracoronary (IC) thrombolytic therapy can reduce microvascular thrombotic burden; however, contemporary studies have produced conflicting outcomes.

OBJECTIVES

This meta-analysis aims to evaluate the efficacy and safety of adjunctive IC thrombolytic therapy at the time of primary percutaneous coronary intervention (PCI) among patients with STEMI.

METHODS

Comprehensive literature search of six electronic databases identified relevant randomised controlled trials. The primary outcome was major adverse cardiac events (MACE). The pooled risk ratio (RR) and weighted mean difference (WMD) with a 95% CI were calculated.

RESULTS

12 studies with 1915 patients were included. IC thrombolysis was associated with a significantly lower incidence of MACE (RR=0.65, 95% CI 0.51 to 0.82, I2=0%, p<0.0004) and improved left ventricular ejection fraction (WMD=1.87; 95% CI 1.07 to 2.67; I2=25%; p<0.0001). Subgroup analysis demonstrated a significant reduction in MACE for trials using non-fibrin (RR=0.39, 95% CI 0.20 to 0.78, I2=0%, p=0.007) and moderately fibrin-specific thrombolytic agents (RR=0.62, 95% CI 0.47 to 0.83, I2=0%, p=0.001). No significant reduction was observed in studies using highly fibrin-specific thrombolytic agents (RR=1.10, 95% CI 0.62 to 1.96, I2=0%, p=0.75). Furthermore, there were no significant differences in mortality (RR=0.91; 95% CI 0.48 to 1.71; I2=0%; p=0.77) or bleeding events (major bleeding, RR=1.24; 95% CI 0.47 to 3.28; I2=0%; p=0.67; minor bleeding, RR=1.47; 95% CI 0.90 to 2.40; I2=0%; p=0.12).

CONCLUSION

Adjunctive IC thrombolysis at the time of primary PCI in patients with STEMI improves clinical and myocardial perfusion parameters without an increased rate of bleeding. Further research is needed to optimise the selection of thrombolytic agents and treatment protocols.

Fibrinolytic Agents in Thromboembolic Diseases: Historical Perspectives and Approved Indications

Fibrinolytic agents catalyze the conversion of the inactive proenzyme plasminogen into the active protease plasmin, degrading fibrin within the thrombus and recanalizing occluded vessels. The history of these medications dates to the discovery of the first fibrinolytic compound, streptokinase, from bacterial cultures in 1933. Over time, researchers identified two other plasminogen activators in human samples, namely urokinase and tissue plasminogen activator (tPA). Subsequently, tPA was cloned using recombinant DNA methods to produce alteplase. Several additional derivatives of tPA, such as tenecteplase and reteplase, were developed to extend the plasma half-life of tPA. Over the past decades, fibrinolytic medications have been widely used to manage patients with venous and arterial thromboembolic events. Currently, alteplase is approved by the U.S. Food and Drug Administration (FDA) for use in patients with pulmonary embolism with hemodynamic compromise, ST-segment elevation myocardial infarction (STEMI), acute ischemic stroke, and central venous access device occlusion. Reteplase and tenecteplase have also received FDA approval for treating patients with STEMI. This review provides an overview of the historical background related to fibrinolytic agents and briefly summarizes their approved indications across various thromboembolic diseases.

Effect of different reperfusion strategies on recovery of ventricular function after ST-segment elevation myocardial infarction: A longitudinal single-center study

Background and Aims

Although the clinical benefit of percutaneous coronary intervention (PCI) on cardiovascular outcomes has been widely investigated, the impact of this revascularization strategy compared to other alternatives on the degree of left ventricular function recovery is poorly demonstrated. In this regard, we investigated whether time delays between the presentation of ST-segment elevation myocardial infarction (STEMI) and PCI in reperfusion strategies have different impacts on left ventricular function recovery.

Methods

In this single-center study, all the patients who presented with STEMI and a reduced left ventricular ejection fraction (LVEF ≤ 40%) were enrolled. Included patients were subjected to four different treatment groups of primary, rescue (immediate transfer for angioplasty due to failed fibrinolytic therapy), facilitated (fibrinolytic therapy followed by angioplasty within 24 h), and deferred (successful fibrinolytic therapy and PCI after 24 h) PCI based on hospital facilities. Echocardiography was performed for all the patients at the time of hospitalization and 6 months later.

Results

A total of 128 patients were included in this study. The LVEF improved by 15.3 ± 6.3%, 11.5 ± 3.61%, 4.0 ± 1.0%, and -1.3 ± 7.0% in primary, rescue, facilitated, and deferred PCI groups, respectively (p < 0.001). Patients undergoing deferred PCI experienced a significantly lower improvement in LVEF compared with primary and rescue PCI (p < 0.001).

Conclusion

Primary PCI demonstrated the most promising recovery in left ventricular function following STEMI compared to other alternative strategies. Performing PCI as soon as possible provides better recovery of LVEF.

Coronary microvascular obstruction and dysfunction in patients with acute myocardial infarction

Despite prompt epicardial recanalization in patients presenting with ST-segment elevation myocardial infarction (STEMI), coronary microvascular obstruction and dysfunction (CMVO) is still fairly common and is associated with poor prognosis. Various pharmacological and mechanical strategies to treat CMVO have been proposed, but the positive results reported in preclinical and small proof-of-concept studies have not translated into benefits in large clinical trials conducted in the modern treatment setting of patients with STEMI. Therefore, the optimal management of these patients remains a topic of debate. In this Review, we appraise the pathophysiological mechanisms of CMVO, explore the evidence and provide future perspectives on strategies to be implemented to reduce the incidence of CMVO and improve prognosis in patients with STEMI.

Impact of capacity building and tele ECG based decision support on change in thrombolysis rate and inhospital and one year mortality in patients with STEMI, using hub and spoke model; multi-phasic intervention trial

BACKGROUND

We report the impact of capacity building and teleconsultation on change in the thrombolysis rates and one-year mortality in patients with STEMI using a hub and the spoke model of STEMI care.

METHODS

Twenty secondary care public hospitals were linked with a teaching hospital as a hub centre and the impact of the intervention on change in ischemic time, thrombolysis rates and all-cause in-hospital and one-year mortality was compared.

RESULTS

29 patients with STEMI were treated during pre-intervention from April 2020 to June 2020 and 255 patients during the post-intervention period from July 2020 to Oct 2021 in spoke centres. 245 patients were reported to a hub centre during the study period. The thrombolysis rate was significantly higher in the spoke centres after intervention (65.5%vs. 27.5 % p < 0.001) and was also significantly higher than in patients treated in a hub centre (65.5 % vs. 45.7 % p < 0.01). The in-hospital mortality was significantly lower in patients treated at spoke centres compared to those treated at the hub centre (7.8 % vs. 15.5 % < 0.003). The significant difference in mortality rate continued at one year (11.0 % vs.18.4 % p < 0.01). The median time from symptoms to thrombolytic therapy was significantly lower in STEMI patients treated in spoke centres compared to a hub centre (230 min vs. 356 min p < 0.001).

CONCLUSION

The hub and spoke model of STEMI care is effective in increasing thrombolysis rate, and decreasing in-hospital and one-year mortality rate.

Outcome of STEMI Patients With Reperfusion Delay of 120 Minutes or More Treated With the Pharmacoinvasive Approach vs PPCI: A Retrospective Study

Background

Primary percutaneous coronary intervention (PPCI) and fibrinolysis have proved to be major discoveries regarding treatment of ST-segment elevation myocardial infarction (STEMI). The threshold at which PPCI becomes less favourable than fibrinolysis remains unclear and controversial. Trials have studied the impact of delayed reperfusion in relation to symptom onset, but to our knowledge, none have focused on the outcome of patients past the expected 120-minute window regarding first medical contact (FMC) in the concomitant era of PPCI and fibrinolysis.

Methods

STEMI patients who presented to a single PPCI-capable hospital, in the period from 2016 to 2020, and were treated with PPCI within 120 -240 minutes after FMC, and those who received fibrinolysis, were included. Outcomes of patients treated with delayed PPCI were compared to those of patients treated with fibrinolysis. The primary endpoint was a net adverse clinical event composite of all-cause mortality, myocardial re-infarction, ischemia-driven target-vessel revascularization, disabling stroke, and major bleeding at discharge.

Results

Inclusion criteria were met for 536 STEMI patients, 429 treated with PPCI and 107 treated with fibrinolysis. The primary endpoint (net adverse clinical events) was not significantly different between the 2 groups (2.8% vs 3.7%, P = 0.61). However, intracranial hemorrhage (0% vs 2.8%, P = 0.008) and bleeding (BARC 3 or 5) (0.9% vs 3.7%, P = 0.048) significantly favoured the PPCI group.

Conclusions

This retrospective study suggests that delayed PPCI may be a safer approach than fibrinolysis in patients with an FMC-to-balloon time of > 120 minutes, owing to reduction in the risk of intracranial and severe bleeding. These retrospective observations should be validated in larger randomized trials.

Single Bolus r-SAK Before Primary PCI for ST-Segment-Elevation Myocardial Infarction

BACKGROUND

It is uncertain whether adjunctive thrombolysis is beneficial for patients with ST-segment-elevation myocardial infarction undergoing percutaneous coronary intervention (PCI) within 120 minutes of presentation. This study was to determine whether in patients presenting with ST-segment-elevation myocardial infarction a single bolus recombinant staphylokinase (r-SAK) before timely PCI leads to improved patency of the infarct-related artery and reduces the infarct size.

METHODS

This is an open-label, prospective, multicenter, randomized study. We enrolled patients aged 18 to 75 years who were within 12 hours of symptom onset of ST-segment-elevation myocardial infarction and expected to undergo PCI within 120 minutes. Patients were administered loading doses of aspirin and ticagrelor and intravenous heparin and were randomized to receive 5 mg bolus of r-SAK or normal saline intravenously before PCI. The primary end point was Thrombolysis in Myocardial Infarction flow grade 2 to 3 or grade 3 in the infarct-related artery 60 minutes after thrombolysis. The infarct size was detected by cardiac magnetic resonance 5 days after randomization. The safety end point was major bleeding (Bleeding Academic Research Consortium ≥3) during 30-day follow-up.

RESULTS

A total of 283 patients were screened from 8 centers and 200 were randomized (median age, 58.5 years; 14% female). The median symptom to thrombolysis time was 252.5 (interquartile range, 142.8-423.8) minutes and thrombolysis to coronary arteriography was 50.0 (interquartile range, 37.0-66.0) minutes. Patients randomized to r-SAK compared with normal saline more often had Thrombolysis in Myocardial Infarction flow grade 2 to 3 (69.0% versus 29.0%; P<0.001) and Thrombolysis in Myocardial Infarction flow grade 3 (51.0% versus 18.0%; P<0.001) and had smaller infarct size (21.91±10.84% versus 26.85±12.37%; P=0.016). There was no increase in major bleeding (r-SAK, 1.0% versus control, 3.0%; P=0.616).

CONCLUSIONS

A single bolus r-SAK before primary PCI for ST-segment-elevation myocardial infarction improves infarct-related artery patency and reduces infarct size without increasing major bleeding.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05023681.

A bibliometric analysis of tenecteplase research utilizing a commonly used citation index

BACKGROUND AND PURPOSE

Tenecteplase is increasingly being used as a first-line treatment for acute ischemic stroke after several randomized studies demonstrated its safety and efficacy, resulting in a massive increase in the number of published studies on this topic. Our aim was to investigate the most impactful authors and relevant journals that have been instrumental in validating this treatment, in hopes of identifying objective research trends that may assist scientists, health organizations, and funding agencies to collaborate and plan future avenues of research.

METHODS

Using the search terms "Tenecteplase" and "Tenecteplase" AND "Stroke," 2683 and 1150 references were queried, respectively, using the abstract and citation database, Scopus. Scopus Citation Analysis was used to categorize the countries and authors who produced the most research. Metadata was retrieved and transferred to bibliographic visualization software, VOSviewer, for co-authorship and co-occurrence analyses to identify trends in tenecteplase research.

RESULTS

Data visualization software identified three tenecteplase research clusters - myocardial infarction, pulmonary embolism, and acute ischemic stroke. Our bibliographic analysis graphically identified that ischemic stroke currently leads both myocardial infarction and pulmonary embolism in annual publications pertaining to tenecteplase therapy, and further pinpointed perfusion imaging and wake-up strokes as the most relevant areas of study. The United States led all countries in tenecteplase publications, including exclusively stroke studies. The European Heart Journal led all journals in overall publications, while Stroke led all journals in stroke-related studies.

CONCLUSIONS

Through the use of bibliographic analysis and data visualization, we identified major articles and journals that reflected and shaped the current landscape of tenecteplase; recognized authors who engaged in tenecteplase research as it progressed from cardiopulmonary disease to stroke; and postulated future avenues of research.

Efficacy and safety of a bolus of half-dose r-SAK prior to primary PCI in ST-elevation myocardial infarction: Rationale and design of the OPTIMA-6 trial

BACKGROUND

Time to reperfusion is the key to the treatment of patients with ST-elevation myocardial infarction (STEMI). It is uncertain whether adjunctive thrombolytic therapy combined with contemporary antiplatelet agent ticagrelor improves outcomes as administered prior to primary percutaneous coronary intervention (PCI) expected to be performed within 120 minutes.

METHODS

OPTIMA-6 is a multicenter, randomized, double-blind, placebo-controlled, and superiority trial to evaluate the efficacy of a bolus of half-dose recombinant staphylokinase (r-SAK) vs placebo prior to timely primary PCI in patients with STEMI. Enrollment began in April 2023 and is expected to enroll 2,260 patients at approximately 50 centers. Patients with acute STEMI presenting ≤12 hours of symptom onset and expected to undergo primary PCI within 120 minutes but more than 30 minutes are to be randomized to a bolus of half-dose r-SAK or placebo. All recruited patients will be mandatory to take aspirin and ticagrelor and receive a bolus of loading dose heparin before the thrombolytic therapy. The primary efficacy endpoint is major adverse cardiovascular events (MACE) within 90 days, and the MACE is defined as a composite of all-cause death, reinfarction, unplanned target vessel revascularization, heart failure or cardiogenic shock, and major ventricular arrhythmia. The primary safety endpoints are major bleeding events (BARC 3, 5) within 90 days.

CONCLUSIONS

OPTIMA-6 will reveal the efficacy and safety of a contemporary facilitated PCI with a bolus of half-dose r-SAK in combination with ticagrelor in patients with STEMI.

STREAM-2: Half-Dose Tenecteplase or Primary Percutaneous Coronary Intervention in Older Patients With ST-Segment-Elevation Myocardial Infarction: A Randomized, Open-Label Trial

BACKGROUND

ST-segment-elevation myocardial infarction (STEMI) guidelines recommend pharmaco-invasive treatment if timely primary percutaneous coronary intervention (PCI) is unavailable. Full-dose tenecteplase is associated with an increased risk of intracranial hemorrhage in older patients. Whether pharmaco-invasive treatment with half-dose tenecteplase is effective and safe in older patients with STEMI is unknown.

METHODS

STREAM-2 (Strategic Reperfusion in Elderly Patients Early After Myocardial Infarction) was an investigator-initiated, open-label, randomized, multicenter study. Patients ≥60 years of age with ≥2 mm ST-segment elevation in 2 contiguous leads, unable to undergo primary PCI within 1 hour, were randomly assigned (2:1) to half-dose tenecteplase followed by coronary angiography and PCI (if indicated) 6 to 24 hours after randomization, or to primary PCI. Efficacy end points of primary interest were ST resolution and the 30-day composite of death, shock, heart failure, or reinfarction. Safety assessments included stroke and nonintracranial bleeding.

RESULTS

Patients were assigned to pharmaco-invasive treatment (n=401) or primary PCI (n=203). Median times from randomization to tenecteplase or sheath insertion were 10 and 81 minutes, respectively. After last angiography, 85.2% of patients undergoing pharmaco-invasive treatment and 78.4% of patients undergoing primary PCI had ≥50% resolution of ST-segment elevation; their residual median sums of ST deviations were 4.5 versus 5.5 mm, respectively. Thrombolysis In Myocardial Infarction flow grade 3 at last angiography was ≈87% in both groups. The composite clinical end point occurred in 12.8% (51/400) of patients undergoing pharmaco-invasive treatment and 13.3% (27/203) of patients undergoing primary PCI (relative risk, 0.96 [95% CI, 0.62-1.48]). Six intracranial hemorrhages occurred in the pharmaco-invasive arm (1.5%): 3 were protocol violations (excess anticoagulation in 2 and uncontrolled hypertension in 1). No intracranial bleeding occurred in the primary PCI arm. The incidence of major nonintracranial bleeding was low in both groups (<1.5%).

CONCLUSIONS

Halving the dose of tenecteplase in a pharmaco-invasive strategy in this early-presenting, older STEMI population was associated with electrocardiographic changes that were at least comparable to those after primary PCI. Similar clinical efficacy and angiographic end points occurred in both treatment groups. The risk of intracranial hemorrhage was higher with half-dose tenecteplase than with primary PCI. If timely PCI is unavailable, this pharmaco-invasive strategy is a reasonable alternative, provided that contraindications to fibrinolysis are observed and excess anticoagulation is avoided.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02777580.

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.

Primary Percutaneous Coronary Intervention and Application of the Pharmacoinvasive Approach Within ST-Elevation Myocardial Infarction Care Networks

The management of acute ST-elevation myocardial infarction (STEMI) has transitioned from observation and reactive treatment of hemodynamic and arrhythmic complications to accelerated reperfusion and application of evidence-based treatment to minimize morbidity and mortality. International research established the importance of timely reperfusion therapy and the application of fibrinolysis, primary percutaneous coronary intervention (PCI), and subsequent development of the pharmacoinvasive approach. Clinician thought leaders developed and investigated comprehensive systems of care to optimize the outcomes of patients with STEMI, with a key focus in Canada being the integration of prehospital paramedics in diagnosis, triage, and treatment. This article will review highlights of these interventions and identify future challenges and opportunities in STEMI patient care.

Tenecteplase or Alteplase: What Is the Thrombolytic Agent of the Future?

Purpose of review

Alteplase has been the thrombolytic of choice for acute ischaemic stroke for more than two decades. A thrombolytic which is easier to administer and with improved or comparable safety and efficacy is desirable. Tenecteplase has emerged as a potential successor, and its off-license use in acute ischaemic stroke has increased in recent years. We aimed to examine the evidence base for each drug and discuss their use in varying patient populations in acute ischaemic stroke.

Recent findings

Several trials comparing tenecteplase and alteplase have reported very recently with the results of the ACT trial strengthening the argument in favour of non-inferiority of tenecteplase to alteplase. Ongoing trials such as ATTEST-2 are of interest, and trials such as TASTE and TEMPO-2 will shed further light on use of tenecteplase in specific populations.

Summary

A single thrombolytic agent for all indications for thrombolysis in acute ischaemic stroke is desirable in streamlining workflows. Based on recent and upcoming trials, guidelines may soon recommend tenecteplase as a suitable alternative to alteplase. The use of tenecteplase in specific subgroups will depend on further recruitment to ongoing clinical trials.

Adjunctive Catheter-Directed Thrombolysis during Primary PCI for ST-Segment Elevation Myocardial Infarction with High Thrombus Burden

BACKGROUND

High coronary thrombus burden has been associated with unfavorable outcomes in patients with ST-segment elevation myocardial infarction (STEMI), the optimal management of which has not yet been established.

METHODS

We assessed the adjunctive catheter-directed thrombolysis (CDT) during primary percutaneous coronary intervention (PCI) in patients with STEMI and high thrombus burden. CDT was defined as intracoronary infusion of tissue plasminogen activator (t-PA; monteplase).

RESULTS

Among the 1849 consecutive patients with STEMI, 263 had high thrombus burden. Moreover, 41 patients received t-PA (CDT group), whereas 222 did not receive it (non-CDT group). No significant differences in bleeding complications and in-hospital and long-term mortalities were observed (9.8% vs. 7.2%, p = 0.53; 7.3% vs. 2.3%, p = 0.11; and 12.6% vs. 17.5%, p = 0.84, CDT vs. non-CDT). In patients who underwent antecedent aspiration thrombectomy during PCI (75.6% CDT group and 87.4% non-CDT group), thrombolysis in myocardial infarction grade 2 or 3 flow rate after thrombectomy was significantly lower in the CDT group than in the non-CDT group (32.2% vs. 61.0%, p < 0.01). However, the final rates improved without significant difference (90.3% vs. 97.4%, p = 0.14).

CONCLUSIONS

Adjunctive CDT appears to be tolerated and feasible for high thrombus burden. Particularly, it may be an option in cases with failed aspiration thrombectomy.

Effects of Intracoronary Pro-urokinase or Tirofiban on Coronary Flow During Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction: A Multi-Center, Placebo-Controlled, Single-Blind, Randomized Clinical Trial

Background: To determine whether intracoronary pro-urokinase or tirofiban improves myocardial reperfusion during primary percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction (STEMI).

Methods: The study included patients with acute STEMI presenting within 12 h of symptoms at 11 hospitals in China between November 2015 and July 2017. Patients were randomized to receive selective intracoronary infusion of recombinant pro-urokinase (20 mg), tirofiban (10 μg/kg), or saline (20 mL) proximal to the infarct-related lesion over a 3-min period before stent implantation during primary PCI. The primary outcome was final corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) after PCI.

Results: This study included 345 patients. Initial angiography identified a high-grade thrombus (TIMI 4–5) in 80% of patients. Final CTFC after PCI was significantly lower in the pro-urokinase (P < 0.001) and tirofiban (P < 0.001) groups than in the saline group and similar between the pro-urokinase and tirofiban groups (P > 0.05). The pro-urokinase (P = 0.008) and tirofiban groups (P = 0.022) had more complete ST-segment resolution at 2 h and lower peak creatine kinase-MB levels after PCI than the saline group (P = 0.006 and P = 0.023). The 30-day incidence of major adverse cardiac events was 4.5% in the pro-urokinase group, 3.4% in the tirofiban group, and 2.6% in the saline group. The incidence of in-hospital TIMI major bleeding events was low and comparable between groups.

Conclusions: Adjunctive intracoronary pro-urokinase or tirofiban given before stent implantation during primary PCI improves myocardial reperfusion without increasing the incidence of major bleeding events.

Residual platelet reactivity, thrombus burden and myocardial reperfusion in patients treated by PCI after successful pre-hospital fibrinolysis compared to primary PCI

We compared residual platelet reactivity and post PCI atherothrombotic burden using OFDI in patients successfully treated by primary PCI versus pharmacoinvasive approach (PI) defined as PCI after successful pre-hospital fibrinolysis. Despite pre-hospital P2Y12-inhibitor loading dose, high rates of high on-treatment platelet reactivity were found at the time of PCI in both groups. Primary PCI patients had higher post stenting thrombus burden and lower rates of final normal myocardial blush grade compared to PI. These findings support the use of a pharmacoinvasive reperfusion strategy especially when primary PCI cannot be timely performed.

Fibrinolytic Therapy in Patients with Acute ST-elevation Myocardial Infarction

Fibrinolytic agents provide an important alternative therapeutic strategy in individuals presenting with ST-elevation myocardial infarction (STEMI). Ultimately, primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for most patients with STEMI, including elderly patients and patients with coronavirus disease 2019 (COVID-19) infection. Fibrinolytic therapy should always be considered when timely primary PCI cannot be delivered appropriately. Clinicians should promptly recognize the signs of fibrinolytic therapy failure and consider rescue PCI. When fibrinolytics are used, coronary angiography and revascularization should not be conducted within the initial 3 hours after fibrinolytic administration.

Adjunctive Intracoronary Fibrinolytic Therapy During Primary Percutaneous Coronary Intervention

Despite routinely restoring epicardial coronary patency, with primary percutaneous coronary intervention (PCI), microvascular obstruction affects approximately half of patients and confers an adverse prognosis. There are no evidence-based treatments for microvascular obstruction. A key contributor to microvascular obstruction is distal embolisation and microvascular thrombi. Adjunctive intracoronary fibrinolytic therapy may reduce thrombotic burden, potentially reducing distal embolisation of atherothrombotic debris to the microcirculation. In this review, the evidence from published randomised trials on the effects of adjunctive intracoronary fibrinolytic therapy during primary PCI is critically appraised, the ongoing randomised trials are described, and conclusions are made from the available evidence. Clinical uncertainties, to be addressed by future research, are highlighted.

Rationale and design of the OPTIMAL-REPERFUSION trial: A prospective randomized multi-center clinical trial comparing different fibrinolysis-transfer percutaneous coronary intervention strategies in acute ST-segment elevation myocardial infarction

Primary percutaneous coronary intervention (PPCI), the preferred reperfusion strategy for all acute ST‐segment elevation myocardial infarction (STEMI) patients, is not universally available in clinical practice. Pharmacoinvasive strategy has been proposed as a therapeutic option in patients with STEMI when timely PPCI is not feasible. However, pharmacoinvasive strategy has potential delay between clinical patency and complete myocardial perfusion. The optimal reperfusion strategy for STEMI patients with anticipated PPCI delay according to current practice is uncertain. OPTIMAL‐REPERFUSION is an investigator‐initiated, prospective, multicenter, randomized, open‐label, superiority trial with blinded evaluation of outcomes. A total of 632 STEMI patients presenting within 6 hours after symptom onset and with an expected time of first medical contact to percutaneous coronary intervention (PCI) ≥120 minute will be randomized to a reduced‐dose facilitated PCI strategy (reduced‐dose fibrinolysis combined with simultaneous transfer for immediate invasive therapy with a time interval between fibrinolysis to PCI < 3 hours) or to standard pharmacoinvasive treatment. The primary endpoint is the composite of death, reinfarction, refractory ischemia, congestive heart failure, or cardiogenic shock at 30‐days. Enrollment of the first patient is planned in March 2021. The recruitment is anticipated to last for 12 to 18 months and to complete in September 2023 with 1 year follow‐up. The OPTIMAL‐REPERFUSION trial will help determine whether reduced‐dose facilitated PCI strategy improves clinical outcomes in patients with STEMI and anticipated PPCI delay. This study is registered with the ClinicalTrials.gov (NCT04752345).

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

BACKGROUND

The effects of intracoronary (IC) thrombolysis therapy in patients with ST-segment elevation myocardial infarction (STEMI) receiving primary percutaneous coronary intervention (PPCI) remain unclear.

METHODS

The meta-analysis was conducted according to the PRISMA statement. All relevant studies were identified by searching the PubMed, EMBASE, Cochrane Library, and Web of Science, with no time or language limitation. The pooled risk ratio (RR) and weighted mean difference (WMD) with a 95% CI were calculated.

RESULTS

Nine randomized controlled trials involving a total of 1341 patients were included. Compared with the control group, IC thrombolysis in patients with STEMI could reduce the incidence of major adverse cardiac events (MACE; RR 0.632, 95% CI, 0.474-0.843, P = .002) and improve left ventricular ejection fraction (RR 0.343, 95% CI, 0.178-0.509, P < .001) and myocardial microcirculation. However, there was no difference noted in the mortality (RR 0.759, 95% CI, 0.347-1.661, P = .490). The incidence rate of major bleeding and minor bleeding was comparable between the 2 groups.

CONCLUSIONS

Intracoronary thrombolysis was associated with improved MACE and myocardial microcirculation in patients with STEMI having PPCI, though it failed to improve mortality.

Index of microvascular resistance and outcomes following intra-coronary thrombolysis with percutaneous intervention in STEMI: a meta-analysis of randomized control trials

Microvascular obstruction following percutaneous coronary intervention (PCI) is highly prevalent and independently associated with adverse clinical outcomes. Microvascular obstruction is determined by index of the microvascular resistance. We performed a systematic review with meta-analysis of all published randomized clinical trials (RCTs) studying the effect of intra-coronary thrombolysis with PCI as compared to standard treatment among patients with ST-segment elevated myocardial infarction. We included 6 RCTs summing up to 947 patients in the final analysis. Intra-coronary thrombolysis resulted in significantly lower index of microvascular resistance [standardized mean difference: - 13.74, 95% confidence interval (CI): - 16.74 to - 10.73, P value < 0.001, I² = 0%]. There was no difference noted in the occurrence of major adverse cardiac events with intra-coronary thrombolysis as compared to standard treatment [Odds ratio:  0.71, 95% CI: 0.46-1.08, P value = 0.11,  I² = 0%]. The absence of heterogeneity deferred us from using dose-response analysis to account for altering dose used across studies. The results of the present meta-analysis highlights the role of intra-coronary thrombolysis in reducing microvascular obstruction. No effect of intra-coronary thrombolysis was noted on the occurrence of major adverse cardiac events.

Sonothrombolysis in the ambulance for ST-elevation myocardial infarction: rationale and protocol

Background

Treatment of ST-elevation myocardial infarction (STEMI) has improved over the years. Current challenges in the management of STEMI are achievement of early reperfusion and the prevention of microvascular injury. Sonothrombolysis has emerged as a potential treatment for acute myocardial infarction, both for epicardial recanalisation as well as improving microvascular perfusion. This study aims to determine safety and feasibility of sonothrombolysis application in STEMI patients in the ambulance.

Methods

Ten patients with STEMI will be included and treated with sonothrombolysis in the ambulance during transfer to the PCI centre. Safety will be assessed by the occurrence of ventricular arrhythmias and shock during sonothrombolysis intervention. Feasibility will be assessed by the extent of protocol completion and myocardial visibility. Efficacy will be determined by angiographic patency rate, ST-elevation resolution, infarct size and left ventricular volumes, and function measured with cardiovascular magnetic resonance imaging, and contrast and strain echocardiography. A comparison will be made with matched controls using an existing STEMI database.

Discussion

Sonothrombolysis is a novel technique for the treatment of cardiovascular thromboembolic disease. The first clinical trials on its use for STEMI have demonstrated promising results. This study will be the first to examine the feasibility of in-ambulance sonothrombolysis for STEMI.

Trial registration

EU Clinical Trials Register (identifier: 2019-001883-31), registered 2020-02-25.

Influence of Clinical Trials of Acute Coronary Syndrome Beyond the Primary Hypothesis: A Systematic Review

Importance

Conducting a clinical trial involves significant risks, time, and resources. The return on investment for these trials, measured by advancing health care and contributions to the scientific literature, is often uncertain.

Objective

To assess the long-term effects of major clinical trials of acute coronary syndromes contemporary to the Assessment of Pexelizumab in Acute Myocardial Infarction (APEX-AMI) trial, which did not achieve its primary objective.

Evidence Review

The Cochrane Central Register of Controlled Trials database was screened for clinical trials of acute coronary syndromes (including unstable angina, ST-elevation myocardial infarction, and non-ST-elevation myocardial infarction) with more than 1000 participants and primary results published between January 1, 2005, and December 31, 2009, in Circulation, European Heart Journal, JAMA, Journal of the American College of Cardiology, The Lancet, and The New England Journal of Medicine. For identified trials, bibliographic information, citations, trial name, registration, inclusion diagnosis, intervention type, sample size, primary outcome result, sponsor information, and academic involvement were extracted. To identify secondary analyses, bibliographic information for citing articles, their citations, and their abstracts were extracted. Clinical practice guideline bibliographies for citations of trial publications were reviewed, and the class and level of evidence of resulting recommendations were extracted.

Findings

Of 784 records screened, 30 were primary publications of 25 clinical trials. Through December 31, 2018, these trials were cited a median of 497 times (interquartile range [IQR], 424-931 citations). Trials that did not achieve their primary objective had fewer primary citations (the number of times that each published journal article with the primary [main] results of a trial was cited) (median, 443 [IQR, 396-468] vs 868 [IQR, 645-1774] citations, P = .006). The frequency of secondary analyses peaked within 5 years of the primary trial at 643. Trials that did not achieve the primary objective had fewer secondary analyses (median, 15 [IQR, 5-31] vs 18 [IQR, 10-43] analyses, P = .44) that were not cited significantly less often (median, 484 [IQR, 191-1299] vs 1124 [IQR, 410-4283] citations, P = .16). All trials were cited by at least 1 clinical practice guideline.

Conclusions and Relevance

This review found that trials that achieved the primary objective were frequently cited. Secondary research activity did not differ by primary result, and the primary trials and secondary analyses contributed to clinical practice recommendations. These data show the long-term importance of clinical trials regardless of primary outcome result.

Tenecteplase Thrombolysis for Acute Ischemic Stroke

Tenecteplase is a fibrinolytic drug with higher fibrin specificity and longer half-life than the standard stroke thrombolytic, alteplase, permitting the convenience of single bolus administration. Tenecteplase, at 0.5 mg/kg, has regulatory approval to treat ST-segment-elevation myocardial infarction, for which it has equivalent 30-day mortality and fewer systemic hemorrhages. Investigated as a thrombolytic for ischemic stroke over the past 15 years, tenecteplase is currently being studied in several phase 3 trials. Based on a systematic literature search, we provide a qualitative synthesis of published stroke clinical trials of tenecteplase that (1) performed randomized comparisons with alteplase, (2) compared different doses of tenecteplase, or (3) provided unique quantitative meta-analyses. Four phase 2 and one phase 3 study performed randomized comparisons with alteplase. These and other phase 2 studies compared different tenecteplase doses and effects on early outcomes of recanalization, reperfusion, and substantial neurological improvement, as well as symptomatic intracranial hemorrhage and 3-month disability on the modified Rankin Scale. Although no single trial prospectively demonstrated superiority or noninferiority of tenecteplase on clinical outcome, meta-analyses of these trials (1585 patients randomized) point to tenecteplase superiority in recanalization of large vessel occlusions and noninferiority in disability-free 3-month outcome, without increases in symptomatic intracranial hemorrhage or mortality. Doses of 0.25 and 0.4 mg/kg have been tested, but no advantage of the higher dose has been suggested by the results. Current clinical practice guidelines for stroke include intravenous tenecteplase at either dose as a second-tier option, with the 0.25 mg/kg dose recommended for large vessel occlusions, based on a phase 2 trial that demonstrated superior recanalization and improved 3-month outcome relative to alteplase. Ongoing randomized phase 3 trials may better define the comparative risks and benefits of tenecteplase and alteplase for stroke thrombolysis and answer questions of tenecteplase efficacy in the >4.5-hour time window, in wake-up stroke, and in combination with endovascular thrombectomy.

Fibrinolytic Strategy for ST-Segment–Elevation Myocardial Infarction

The ongoing coronavirus disease 2019 pandemic has resulted in additional challenges for systems designed to perform expeditious primary percutaneous coronary intervention for patients presenting with ST-segment–elevation myocardial infarction. There are 2 important considerations: the guideline-recommended time goals were difficult to achieve for many patients in high-income countries even before the pandemic, and there is a steep increase in mortality when primary percutaneous coronary intervention cannot be delivered in a timely fashion. Although the use of fibrinolytic therapy has progressively decreased over the last several decades in high-income countries, in circumstances when delays in timely delivery of primary percutaneous coronary intervention are expected, a modern fibrinolytic-based pharmacoinvasive strategy may need to be considered. The purpose of this review is to systematically discuss the contemporary role of an evidence-based fibrinolytic reperfusion strategy as part of a pharmacoinvasive approach, in the context of the emerging coronavirus disease 2019 pandemic.

Management and outcomes of uncomplicated ST-segment elevation myocardial infarction patients transferred after fibrinolytic therapy

BACKGROUND

This study sought to assess the contemporary outcomes of patients transferred after receiving fibrinolytic therapy ('drip-and-ship') for ST-segment elevation myocardial infarction (STEMI) in the United States.

METHODS

During 2009-2016, adults (>18 years) with STEMI (>18 years) without cardiac arrest and cardiogenic shock that received fibrinolytic therapy and were subsequently transferred were identified using the National Inpatient Sample (NIS). These admissions were divided into those undergoing fibrinolysis alone, subsequent coronary angiography (CA) without revascularization and subsequent CA with revascularization. Outcomes of interest included in-hospital mortality, resource utilization, and discharge disposition.

RESULTS

A total of 27,454 STEMI admissions receiving a 'drip-and-ship strategy', 96.3% and 85.8% received subsequent coronary angiography and revascularization Admissions receiving CA and revascularization were younger, male, and with lower comorbidity. The fibrinolysis alone cohort had higher rates of organ failure, hemorrhagic sequelae, and intracranial hemorrhage. Compared to the fibrinolysis cohort, CA with revascularization (adjusted odds ratio [aOR] 0.17 [95% confidence interval {CI} 0.11-0.27]; p < .001) but not CA without revascularization (OR 0.72 [95% CI 0.42-1.21]; p = .21) was associated with lower in-hospital mortality. The fibrinolysis alone cohort had higher use of do-not-resuscitate status (12.8%) and fewer discharges to home (56.6%) compared to cohorts undergoing CA without (1.7%; 86.9%) and with (0.3% and 91.2%) revascularization, respectively. Presence of complications, do-not-resuscitate status, and higher comorbidity were predictive of lower CA and revascularization use.

CONCLUSION

Fibrinolysis with subsequent revascularization is associated with excellent outcomes in STEMI. Admissions receiving fibrinolysis alone were systematically different, sicker and had poorer outcomes.

The Second Strategic Reperfusion Early After Myocardial Infarction (STREAM-2) study optimizing pharmacoinvasive reperfusion strategy in older ST-elevation myocardial infarction patients

BACKGROUND

The STREAM study demonstrated that a pharmaco-invasive strategy was at least as effective as primary PCI (pPCI) in patients presenting early with ST-elevation myocardial infarction (STEMI). The current trial is a response to the finding that reduced intracranial hemorrhage (ICH) in patients ≥75 years occurred after halving the dose of tenecteplase. Additionally, a subsequent analysis of full dose tenecteplase or alteplase in the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT) trials demonstrated a steep increase in bleeding events beginning around the age of 60 years.

METHODS

STREAM-2 will compare the efficacy and safety of a novel pharmaco-invasive strategy as compared to routine pPCI in STEMI patients ≥60 years presenting within 3 hours from symptom onset. In the pharmaco-invasive arm patients will receive half-dose tenecteplase, as soon as possible before transport to a PCI center. In the pPCI arm, patients will be treated according to optimal standard of care defined by local practice. The key criteria for efficacy will be the number of patients achieving ≥50% ST-segment resolution before and after PCI in lead with maximal ST elevation at baseline and the clinical endpoints of death, congestive heart failure, shock or re-infarction, rescue PCI and aborted myocardial infarction, both singularly and as a composite at 30 days. Key safety criteria are total stroke, ICH and major non-intracranial bleeds. Approximately 600 patients will be randomized (400 to pharmaco-invasive treatment and 200 to pPCI). An interim analysis is planned after 300 patients are enrolled to consider adapting the trial to include a larger sample size aimed at undertaking a formal confirmatory trial.

DISCUSSION

The study will provide new insights aimed at establishing an effective and safer pharmaco-invasive treatment for the growing population of older STEMI patients who cannot undergo timely pPCI.

Comparison of Reperfusion Strategies for ST-Segment-Elevation Myocardial Infarction: A Multivariate Network Meta-analysis

Background We systematically reviewed trials comparing different reperfusion strategies for ST-segment-elevation myocardial infarction and used multivariate network meta-analysis to compare outcomes across these strategies. Methods and Results We identified 31 contemporary trials in which patients with ST-segment-elevation myocardial infarction were randomized to ≥2 of the following strategies: fibrinolytic therapy (n=4212), primary percutaneous coronary intervention (PCI) (n=6139), or fibrinolysis followed by routine early PCI (n=5006). We categorized the last approach as "facilitated PCI" when the median time interval between fibrinolysis to PCI was <2 hours (n=2259) and as a "pharmacoinvasive approach" when this interval was ≥2 hours (n=2747). We evaluated outcomes of death, nonfatal reinfarction, stroke, and major bleeding using a multivariate network meta-analysis and a Bayesian analysis. Among the strategies evaluated, primary PCI was associated with the lowest risk of mortality, nonfatal reinfarction, and stroke. For mortality, primary PCI had an odds ratio of 0.73 (95% CI, 0.61-0.89) when compared with fibrinolytic therapy. Of the remaining strategies, the pharmacoinvasive approach was the next most favorable with an odds ratio for death of 0.79 (95% CI, 0.59-1.08) compared with fibrinolytic therapy. The Bayesian model indicated that when the 2 strategies examining routine early invasive therapy following fibrinolysis were directly compared, the probability of adverse outcomes was lower for the pharmacoinvasive approach relative to facilitated PCI. Conclusions A pharmacoinvasive approach is safer and more effective than facilitated PCI and fibrinolytic therapy alone. This has significant implications for ST-segment-elevation myocardial infarction care in settings where timely access to primary PCI, the preferred treatment for ST-segment-elevation myocardial infarction, is not available.

Management of ST-segment-elevation myocardial infarction during the coronavirus disease 2019 (COVID-19) outbreak: Iranian"247" National Committee's position paper on primary percutaneous coronary intervention

World Health Organization has designated coronavirus disease 2019 (COVID‐19) as a pandemic. During the past several weeks, a considerable burden has been imposed on the Iranian's healthcare system. The present document reviewed the latest evidence and expert opinion regarding the management of ST‐segment‐elevation myocardial infarction during the outbreak of COVID‐19 and outlines a practical algorithm for it.

Sonothrombolysis Improves Myocardial Dynamics and Microvascular Obstruction Preventing Left Ventricular Remodeling in Patients With ST Elevation Myocardial Infarction

Background:

It has recently been demonstrated that high-energy diagnostic transthoracic ultrasound and intravenous microbubbles dissolve thrombi (sonothrombolysis) and increase angiographic recanalization rates in patients with ST-segment–elevation myocardial infarction. We aimed to study the effect of sonothrombolysis on the myocardial dynamics and infarct size obtained by real-time myocardial perfusion echocardiography and their value in preventing left ventricular remodeling.

Methods:

One hundred patients with ST-segment–elevation myocardial infarction were randomized to therapy (50 patients treated with sonothrombolysis and percutaneous coronary intervention) or control (50 patients treated with percutaneous coronary intervention only). Left ventricular volumes, ejection fraction, risk area (before treatment), myocardial perfusion defect over time (infarct size), and global longitudinal strain were determined by quantitative real-time myocardial perfusion echocardiography and speckle tracking echocardiography imaging.

Results:

Risk area was similar in the control and therapy groups (19.2±10.1% versus 20.7±8.9%; P =0.56) before treatment. The therapy group presented a behavior significantly different than control group over time ( P <0.001). The perfusion defect was smaller in the therapy at 48 to 72 hours even in the subgroup of patients with no recanalization at first angiography (12.9±6.5% therapy versus 18.8±9.9% control; P =0.015). The left ventricular global longitudinal strain was higher in the therapy than control immediately after percutaneous coronary intervention (14.1±4.1% versus 12.0±3.3%; P =0.012), and this difference was maintained until 6 months (17.1±3.5% versus 13.6±3.6%; P <0.001). The only predictor of left ventricular remodeling was treatment with sonothrombolysis: the control group was more likely to exhibit left ventricular remodeling with an odds ratio of 2.79 ([95% CI, 0.13–6.86]; P =0.026).

Conclusions:

Sonothrombolysis reduces microvascular obstruction and improves myocardial dynamics in patients with ST-segment–elevation myocardial infarction and is an independent predictor of left ventricular remodeling over time.

Low-Dose Alteplase During Primary Percutaneous Coronary Intervention According to Ischemic Time

BACKGROUND

Microvascular obstruction affects one-half of patients with ST-segment elevation myocardial infarction and confers an adverse prognosis.

OBJECTIVES

This study aimed to determine whether the efficacy and safety of a therapeutic strategy involving low-dose intracoronary alteplase infused early after coronary reperfusion associates with ischemic time.

METHODS

This study was conducted in a prospective, multicenter, parallel group, 1:1:1 randomized, dose-ranging trial in patients undergoing primary percutaneous coronary intervention. Ischemic time, defined as the time from symptom onset to coronary reperfusion, was a pre-specified subgroup of interest. Between March 17, 2016, and December 21, 2017, 440 patients, presenting with ST-segment elevation myocardial infarction within 6 h of symptom onset (<2 h, n = 107; ≥2 h but <4 h, n = 235; ≥4 h to 6 h, n = 98), were enrolled at 11 U.K. hospitals. Participants were randomly assigned to treatment with placebo (n = 151), alteplase 10 mg (n = 144), or alteplase 20 mg (n = 145). The primary outcome was the amount of microvascular obstruction (MVO) (percentage of left ventricular mass) quantified by cardiac magnetic resonance imaging at 2 to 7 days (available for 396 of 440).

RESULTS

Overall, there was no association between alteplase dose and the extent of MVO (p for trend = 0.128). However, in patients with an ischemic time ≥4 to 6 h, alteplase increased the mean extent of MVO compared with placebo: 1.14% (placebo) versus 3.11% (10 mg) versus 5.20% (20 mg); p = 0.009 for the trend. The interaction between ischemic time and alteplase dose was statistically significant (p = 0.018).

CONCLUSION

In patients presenting with ST-segment elevation myocardial infarction and an ischemic time ≥4 to 6 h, adjunctive treatment with low-dose intracoronary alteplase during primary percutaneous coronary intervention was associated with increased MVO. Intracoronary alteplase may be harmful for this subgroup. (A Trial of Low-Dose Adjunctive Alteplase During Primary PCI [T-TIME]; NCT02257294).

Feasibility and Safety of Low-Dose Intra-Coronary Tenecteplase During Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction (ICE T-TIMI 49)

Following primary percutaneous coronary intervention (PPCI) for ST segment elevation myocardial infarction, microvascular perfusion is often impaired secondary to thrombotic embolization. Intracoronary (IC) fibrinolytic administration may reduce thrombotic burden and distal embolization. The ICE-T-TIMI-49 study evaluated the feasibility and safety of low-dose IC tenecteplase (TNK) during PPCI. The study randomized 40 PPCI patients to a volume matched bolus of IC TNK (4 mg) (n = 20) or IC saline placebo (n = 20) before and following PPCI. The primary end point was percent diameter stenosis of the culprit lesion following first bolus. The primary end point did not differ between IC placebo (median 100%, interquartile range [IQR] 83.0,100.0) and IC TNK (median 100% stenosis, IQR 91.0,100.0; p = 0.522). However, the proportion of patients with reduction in thrombus following first bolus tended to be greater with IC TNK (placebo: 12.5% vs IC TNK: 40.0%, p = 0.133). Following PPCI, the corrected Thrombolysis In Myocardial Infarction (TIMI) frame count (cTFC) was lower (faster) with placebo (16.0 frames [IQR 12.0,24.0] vs 24.0 frames [22.0,32.0], p = 0.045) due to a trend towards greater frequency of hyperemia (cTFC <14), a marker of distal embolization (50.0% vs 8.3%, p = 0.056). There was no difference in TIMI major bleeds and no intracranial hemorrhage. In conclusion, treatment with low-dose IC TNK appears safe and well tolerated during PPCI. Although IC TNK administration did not improve percent stenosis, a trend towards reduced thrombus burden was demonstrated with less hyperemia (a marker of distal embolization). Our findings provide support for a large randomized study.

Efficacy and Safety of Pharmacoinvasive Strategy Compared to Primary Percutaneous Coronary Intervention in the Management of ST-Segment Elevation Myocardial Infarction: A Prospective Country-Wide Registry

Background:

A pharmacoinvasive reperfusion strategy is recommended for ST-elevation myocardial infarction (STEMI) patients when primary percutaneous coronary intervention (PCI) cannot be achieved in a timely fashion. This is based on a limited number of trials. The effectiveness of this strategy in the real-world is unclear.

Objectives:

To compare the effectiveness of pharmacoinvasive strategy versus primary PCI using a nationwide prospective registry of STEMI patients.

Methods:

We examined 936 STEMI patients from the reperfusion in ST-elevation myocardial infarction in Kuwait (REPERFUSE Kuwait) registry who underwent either primary PCI or pharmacoinvasive reperfusion. A composite outcome was measured based on death, congestive heart failure, reinfarction or stroke prospectively ascertained during hospital stay and up to one-year follow-up. The association between reperfusion strategy and the composite outcome was assessed using multivariate regression and Poisson proportional hazard model.

Results:

Compared to the pharmacoinvasive group, those undergoing primary PCI had higher Killip class on presentation and required more blood transfusions during hospitalization. There was no significant difference between primary PCI and pharmacoinvasive strategy with regards to the incidence of the composite outcome during the in-hospital period (RR = 1.0; 95% CI 0.98–1.02; p = 0.96) after adjustment for possible confounders. Over one-year follow-up, the survival of the two groups was not different (p = 0.66). The incidence of major bleeding was similar in both groups.

Conclusion:

STEMI patients treated with a pharmacoinvasive strategy have comparable outcomes to those treated with primary PCI with no increased risk of major bleeding. These real-world data support the use of a pharmacoinvasive strategy when primary PCI cannot be achieved in a timely fashion.

High-throughput targeted proteomics discovery approach and spontaneous reperfusion in ST-segment elevation myocardial infarction

BACKGROUND

Although spontaneous reperfusion (SR) prior to primary percutaneous coronary intervention (pPCI) is associated with improved outcomes, its pathophysiology remains unclear. The objective of the study was to explore associations between SR in ST-segment elevation myocardial infarction (STEMI) using a multimarker cardiovascular proteins strategy METHODS: We evaluated STEMI patients from the Assessment of Pexelizumab in Acute Myocardial Infarction trial treated with pPCI within 6 hours from symptom onset. SR was core laboratory-defined as pre-PCI Thrombolysis in Myocardial Infarction flow 2 or 3. Ninety-one cardiovascular disease-related serum biomarkers drawn prior to PCI were analyzed using a high-throughput "targeted discovery" panel. Expression levels for individual biomarkers were compared between patients with/without SR. A hierarchical clustering method of biomarkers identified clusters of biomarkers that differentiated the 2 groups. Associations between individual biomarkers and clusters with SR were further evaluated by multivariable logistic regression.

RESULTS

Of 683 patients studied, 290 had spontaneous reperfusion; those with compared to without SR were more likely noninferior STEMI and had lower clinical acuity and lower baseline levels of troponin and creatine kinase. SR was associated with a lower occurrence of 90-day composite of death, heart failure, or cardiogenic shock. Fifty-two of 91 individual biomarkers were significantly univariably associated with SR. Forty-five remained significant with adjustment for false discovery rate. Using cluster analysis, 26 biomarkers clusters were identified, explaining 72% of total covariance, and 13 biomarker clusters were significantly associated with SR after multivariable adjustment. SR was associated with higher mean expression levels of proteins in all 13 clusters. The cluster most strongly associated with SR consisted of novel proteins across various distinct, yet interlinked, pathobiological processes (kallikrein-6, matrix extracellular phosphoglycoprotein, matrix mettaloproteinaise-3, and elafin).

CONCLUSIONS

Spontaneous reperfusion prior to pPCI in STEMI was associated with a lower risk of adverse clinical events. These exploratory data from a targeted discovery proteomics platform identifies novel proteins across diverse, yet complementary, pathobiological axes that show promise in providing mechanistic insights into spontaneous reperfusion in STEMI.

CONDENSED ABSTRACT

Spontaneous reperfusion has been established with improved STEMI outcomes, yet its pathobiology is unclear and appears to involve diverse physiological processes. Using a 91-biomarker high-throughput proteomics platform, we studied 683 STEMI patients in the APEX AMI trial (290 had core laboratory-adjudicated pre-PCI TIMI 2/3 flow) and identified 52 proteins that univariably associate with spontaneous reperfusion. Cluster analysis identified 26 biomarker clusters (explaining 72% of total variance), 13 of which, after multivariable adjustment, were significantly associated with spontaneous reperfusion. Four proteins (kallikrein-6, matrix extracellular phosphoglycoprotein, matrix mettaloproteinaise-3, and elafin) across diverse, yet complementary, pathways appear to be associated most strongly with spontaneous reperfusion.

Effects of Intracoronary Alteplase on Microvascular Function in Acute Myocardial Infarction

Background

Impaired microcirculatory reperfusion worsens prognosis following acute ST‐segment–elevation myocardial infarction. In the T‐TIME (A Trial of Low‐Dose Adjunctive Alteplase During Primary PCI) trial, microvascular obstruction on cardiovascular magnetic resonance imaging did not differ with adjunctive, low‐dose, intracoronary alteplase (10 or 20 mg) versus placebo during primary percutaneous coronary intervention. We evaluated the effects of intracoronary alteplase, during primary percutaneous coronary intervention, on the index of microcirculatory resistance, coronary flow reserve, and resistive reserve ratio.

Methods and Results

A prespecified physiology substudy of the T‐TIME trial. From 2016 to 2017, patients with ST‐segment–elevation myocardial infarction ≤6 hours from symptom onset were randomized in a double‐blind study to receive alteplase 20 mg, alteplase 10 mg, or placebo infused into the culprit artery postreperfusion, but prestenting. Index of microcirculatory resistance, coronary flow reserve, and resistive reserve ratio were measured after percutaneous coronary intervention. Cardiovascular magnetic resonance was performed at 2 to 7 days and 3 months. Analyses in relation to ischemic time (<2, 2–4, and ≥4 hours) were prespecified. One hundred forty‐four patients (mean age, 59±11 years; 80% male) were prospectively enrolled, representing 33% of the overall population (n=440). Overall, index of microcirculatory resistance (median, 29.5; interquartile range, 17.0–55.0), coronary flow reserve(1.4 [1.1–2.0]), and resistive reserve ratio (1.7 [1.3–2.3]) at the end of percutaneous coronary intervention did not differ between treatment groups. Interactions were observed between ischemic time and alteplase for coronary flow reserve (P=0.013), resistive reserve ratio (P=0.026), and microvascular obstruction (P=0.022), but not index of microcirculatory resistance.

Conclusions

In ST‐segment–elevation myocardial infarction with ischemic time ≤6 hours, there was overall no difference in microvascular function with alteplase versus placebo.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02257294.