Aborted myocardial infarction in intracoronary compared with standard intravenous abciximab administration in patients undergoing primary percutaneous coronary intervention for ST-elevation myocardial infarction

Intracoronary Versus Intravenous Low-Dose Tirofiban in Patients With ST-Elevation Myocardial Infarction: A Meta-Analysis of Randomised Controlled Trials

BACKGROUND

This meta-analysis aimed to evaluate the effects of intracoronary (IC) low-dose tirofiban versus intravenous (IV) administration on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

All published randomised controlled trials (RCTs) comparing the effects of IC low-dose tirofiban (a bolus of ≤10 ug/kg) versus IV administration in patients with STEMI were identified by searching PubMed, EMBASE, Cochrane Library, and ISI Web of Science from inception to June 2023, with no language restriction. The risk ratio (RR) with 95% confidence intervals (CI) and the weighted mean difference (WMD) with 95% CI were calculated.

RESULTS

Eleven RCTs involving 1,802 patients were included. Compared with the IV group, IC low-dose tirofiban was associated with improved major adverse cardiac events rate (RR 0.595, 95% CI 0.442-0.802; p=0.001), left ventricular ejection fraction (WMD 1.982, 95% CI 0.565-3.398; p=0.006), thrombolysis in myocardial infarction (TIMI) flow grade (RR 1.065, 95% CI 1.004-1.131; p=0.037), and TIMI myocardial perfusion grade (RR 1.194, 95% CI 1.001-1.425; p=0.049). The two groups had no significant difference in bleeding events (RR 0.952, 95% CI 0.709-1.279; p=0.745).

CONCLUSIONS

Intracoronary low-dose tirofiban administration may be a safe and effective alternative to IV administration in STEMI patients.

Intracoronary compared with intravenous bolus tirofiban on the microvascular obstruction in patients with STEMI undergoing PCI: a cardiac MR study

To investigate the potential effect of intracoronary administration of the glycoprotein IIb/IIIa inhibitor tirofiban on the microvascular obstruction (MVO) assessed by cardiac magnetic resonance (CMR) imaging compared to the intravenous route in patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention (PCI). Two hundred eight patients were randomized into two groups (tirofiban i.v. and tirofiban i.c.). CMR was completed within 3-7 days after ST-segment-elevation myocardial infarction. One hundred thirty-two patients had a follow-up CMR at 6 months after discharge. The primary end point was the CMR measurements including myocardium strain, myocardial perfusion index, final infarct size, prevalence and extent of MVO, and the change of left ventricular end-diastolic volume (LVEDV) at six months follow-up. The second endpoint was major adverse cardiovascular events (composite of all-cause death, nonfatal reinfarction and congestive heart failure) in one year. The MVO prevalence and extent [56% versus 36%, p = 0.004; 2.08 (IQR: 1.18-5.07) g versus 1.68 (IQR: 0.30-3.28) g, p = 0.041] showed a significant difference between the intravenous and intracoronary groups. Global left ventricular peak longitudinal strain was significantly different in intracoronary groups compared to intravenous groups, - 12.5 [IQR: - 13.4 to - 10.9] versus - 12.3 [IQR: - 13.4 to - 10.4], respectively (P = 0.042). Infarcted myocardial perfusion index was significantly different in intracoronary groups compared to intravenous groups, 0.11 [IQR: 0.08 to 0.15] versus 0.09 [IQR: 0.07 to 0.14], respectively (P = 0.026). Intracoronary tirofiban was associated with a higher change in LVEDV compared with intravenous group (- 10.2% [IQR: - 13.7% to - 2.6%] versus 1.3% [IQR: - 5.6% to 6.1%], p < 0.001). Intracoronary tirofiban application showed no benefit on the occurrence of major adverse cardiovascular events during follow-up compared to intravenous administration. This CMR study in ST-segment-elevation myocardial infarction patients showed a benefit in MVO and left ventricular remodeling for intracoronary tirofiban administration compared to intravenous administration in patients undergoing PCI.

Intracoronary Bivalirudin Bolus in ST-Elevation Myocardial Infarction Patients Treated with Primary Angioplasty: Theoretical Bases, Clinical Experience, and Future Applications

Intracoronary thrombus is a common finding in acute coronary syndromes and often correlates with adverse prognosis and complications during percutaneous coronary interventions (PCIs). Bivalirudin, a direct thrombin inhibitor, is one of the recommended antithrombotic treatments for PCI in ST-elevation myocardial infarction (STEMI). The intracoronary administration of a bivalirudin loading dose, even if off-label, offers theoretical advantages over the standard intravenous route, providing a very high drug concentration in the infarct-related artery without increasing the total dose of the drug administered. After the description in case reports of such an approach, a larger scale experience was recently reported in a large cohort of patients with STEMI treated during primary PCI with a bivalirudin intracoronary loading dose followed by the standard intravenous maintenance infusion. As a control group, a propensity score-matched cohort of patients undergoing primary PCI treated with intravenous bivalirudin in the same institution was selected. Compared with the intravenous bolus, the intracoronary administration of bivalirudin was associated with improved ST-segment resolution, lower post-procedural peak CK-MB levels, and better Thrombolysis in Myocardial Infarction (TIMI) frame count values, without difference in bleeding rates. Thus, this new promising antithrombotic strategy, based on the intracoronary administration of a bivalirudin loading dose during primary PCI, appeared safe, improved myocardial reperfusion, and mitigated enzymatic myocardial infarct size compared with the standard intravenous protocol. Randomized trials are warranted to confirm these results and evaluate the possible long-term clinical benefits.

Pharmacologic Therapy for Reducing Myocardial Infarct Size in Clinical Trials

In patients with acute ST-segment elevation myocardial infarction, early, successful, and durable reperfusion therapy optimizes the likelihood of favorable outcomes. Fibrinolysis and primary percutaneous coronary intervention improve survival compared to no reperfusion therapy in large part by reducing infarct size (IS) and preserving left ventricular ejection fraction. There is direct correlation between IS and clinical outcomes. In this article, we will review some of the more promising pharmacological agents geared toward reduction in IS, discuss the major pathways that can lead to this desirable outcome, and evaluate the results of clinical trials performed with these and other compounds.

Current state of clinical translation of cardioprotective agents for acute myocardial infarction

There is continued interest in the concept of limiting myocardial infarct size with adjunctive agents administered along with reperfusion injury; however, there remains considerable controversy in the literature. The purpose of this article is to review the medical literature on clinical trials performed during the past 3 years that have attempted to reduce myocardial infarct size by administration of adjunctive therapies along with reperfusion therapy. A PubMed-driven literature search revealed a host of clinical trials focusing on the following prominent types of therapies: endogenous conditioning (postconditioning and remote ischemic conditioning); rapid cooling; pharmacological therapy (cyclosporine, abciximab, clopidogrel, tirofiban, erythropoietin, thrombus aspiration, adenosine, glucose-insulin-potassium, statins, antidiabetic agents, FX06, iron chelation, and ranolazine). Although there remains some controversy, quite a few of these studies showed that adjunctive therapy further reduced myocardial infarct size when coupled with reperfusion. Antiplatelet agents are emerging as some of the newest agents that seem to have cardioprotective capabilities. Postconditioning has become a bit more controversial in the clinical literature; remote conditioning, early and rapid cooling, adenosine, and ranolazine are intriguing therapies deserving of larger studies. Certain agents and maneuvers, such as erythropoietin, protein kinase C δ inhibitors, iron chelation, and intra-aortic balloon counterpulsation, perhaps should be retired. The correct adjunctive therapy administered along with reperfusion has the capability of further reducing myocardial injury during ST-segment-elevation myocardial infarction.

Myocardial oedema as the sole marker of acute injury in Takotsubo cardiomyopathy: a cardiovascular magnetic resonance (CMR) study

PURPOSE

The main hallmark of Takotsubo cardiomyopathy (TT-CMP) is transient ischaemia, with completely reversible regional contractile dysfunction, which involves the mid-apical segments and shows no angiographic signs of coronary artery disease (CAD). The acute and reversible myocardial injury suggests that tissue oedema may be an important marker of disease.

MATERIALS AND METHODS

Seventeen patients with a clinical and angiographic diagnosis of TT-CMP underwent cardiovascular magnetic resonance (CMR) imaging in the acute phase and at follow-up after 4 months. A standard acquisition protocol including turbo spin echo (TSE) T2-weighted short-tau inversion-recovery (T2 STIR), steady-state free-precession cine (SSFP cine) and lateenhancement (LE) imaging after gadolinium benzyloxypropionic tetraacetic acid (Gd-BOPTA) administration was performed. All images were analysed, and data on oedema and LE were correlated with regional dysfunction and histological findings from endomyocardial biopsy (EMB) where available.

RESULTS

In all patients, T2 STIR images showed a diffuse homogeneous hyperintensity that extended to all mid-apical segments and perfectly matched the area of regional dysfunction, reflecting tissue oedema. In the five patients who underwent EMB, histology confirmed the massive interstitial oedema associated with typical contraction-band necrosis. No cases of LE were observed. At follow-up, complete regression of oedema was observed in all cases, with significant recovery of regional and global left ventricular (LV) function (ejection fraction from 48.7% to 59.8%).

CONCLUSIONS

Myocardial oedema on CMR is a characteristic feature of acute TT-CMP, which reflects acute inflammation and acute myocardial injury. It could therefore be used as a specific marker of disease severity.