Comparison of Intracoronary Epinephrine and Adenosine for No-Reflow in Normotensive Patients With Acute Coronary Syndrome (COAR Trial)

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.

Effect of preinitiated glucose-insulin-potassium strategy for patients with undergoing planned percutaneous coronary intervention: a systematic review and meta-analysis

OBJECTIVES

Whether the glucose-insulin-potassium (GIK) should be used as an adjuvant therapy for ischaemic myocardial disease remains controversial nowadays reperfusion era. This meta-analysis aimed to assess the effects of preinitiated GIK for patients undergoing planned percutaneous coronary intervention (PCI).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Web of science, MEDLINE, Embase, Cochrane Library and ClinicalTrials.gov were searched through 27 November 2022.

ELIGIBILITY CRITERIA

Only randomised controlled trials involving participants preinitiated with GIK or placebo before planned PCI were included.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers used standardised methods to search, screen and code included trials. Risk of bias was assessed with the Cochrane tool. Pooled analysis was conducted using random or effects models according to the heterogeneity. Subgroup analyses were carried out for dosage of GIK and if with ongoing myocardial ischaemia.

RESULTS

13 randomised controlled trials (RCTs) including 3754 participants were evaluated. We found patients preconditioned with GIK before PCI showed a significant increase in Thrombolysis in Myocardial Infarction 3 flow events after angioplasty (OR 1.59, 95% CI 1.03 to 2.46, p=0.04), also revealed improved in-hospital left ventricular ejection fraction (weighed mean difference, WMD 1.62, 95% CI 0.21 to 3.03, p=0.02) and myocardial salvage index (WMD 0.09, 95% CI 0.01 to 0.16, p=0.03). Nevertheless, no benefit was observed in all-cause mortality neither on 30-day (OR 0.81, 95% CI 0.59 to 1.11, p=0.18) nor 6 months (OR 1.02, 95% CI 0.42 to 2.46, p=0.97). Furthermore, GIK intervention was associated with higher occurrences of complications such as phlebitis (OR 10.13, 95% CI 1.74 to 59.00, p=0.01) and hypoglycaemia (OR 10.43, 95% CI 1.32 to 82.29, p=0.03), but not hyperkalaemia (OR 9.36, 95% CI 0.50 to 175.27, p=0.13), liquid overload (OR 1.02, 95% CI 0.25 to 4.13, p=0.98) or in-hospital heart failure (OR 0.42, 95% CI 0.06 to 2.96, p=0.39).

CONCLUSIONS

Our study shows preconditioning GIK exhibits myocardial reperfusion and cardiac function benefits for patients planning to receive PCI intervention, while also some complications such as phlebitis and hypoglycaemia accompany.

PROSPERO REGISTRATION NUMBER

CRD42022326334.

Tongmai Yangxin pill alleviates myocardial no-reflow by activating GPER to regulate HIF-1α signaling and downstream potassium channels

CONTEXT

The Tongmai Yangxin pill (TMYX) has potential clinical effects on no-reflow (NR); however, the effective substances and mechanisms remain unclear.

OBJECTIVE

This study evaluates the cardioprotective effects and molecular mechanisms of TMYX against NR.

MATERIALS AND METHODS

We used a myocardial NR rat model to confirm the effect and mechanism of action of TMYX in alleviating NR. Sprague-Dawley (SD) rats were divided into Control (Con), sham, NR, TMYX (4.0 g/kg), and sodium nitroprusside (SNP, 5.0 mg/kg), and received their treatments once a day for one week. In vitro studies in isolated coronary microvasculature of NR rats and in silico network pharmacology analyses were performed to reveal the underlying mechanisms of TMYX and determine the main components, targets, and pathways of TMYX, respectively.

RESULTS

TMYX (4.0 g/kg) showed therapeutic effects on NR by improving the cardiac structure and function, reducing NR, ischemic areas, and cardiomyocyte injury, and decreasing the expression of cardiac troponin I (cTnI). Moreover, the mechanism of TMYX predicted by network pharmacology is related to the HIF-1, NF-κB, and TNF signaling pathways. In vivo, TMYX decreased the expression of MPO, NF-κB, and TNF-α and increased the expression of GPER, p-ERK, and HIF-1α. In vitro, TMYX enhanced the diastolic function of coronary microvascular cells; however, this effect was inhibited by G-15, H-89, L-NAME, ODQ and four K⁺ channel inhibitors.

CONCLUSIONS

TMYX exerts its pharmacological effects in the treatment of NR via multiple targets. However, the contribution of each pathway was not detected, and the mechanisms should be further investigated.

Microvascular Obstruction in Acute Myocardial Infarction, a Potential Therapeutic Target

Microvascular obstruction (MVO) is a recognised phenomenon following mechanical reperfusion in patients presenting with ST-segment elevation myocardial infarction (STEMI). Invasive and non-invasive modalities to detect and measure the extent of MVO vary in their accuracy, suggesting that this phenomenon may reflect a spectrum of pathophysiological changes at the level of coronary microcirculation. The importance of detecting MVO lies in the observation that its presence adds incremental risk to patients following STEMI treatment. This increased risk is associated with adverse cardiac remodelling seen on cardiac imaging, increased infarct size, and worse patient outcomes. This review provides an outline of the pathophysiology, clinical implications, and prognosis of MVO in STEMI. It describes historic and novel pharmacological and non-pharmacological therapies to address this phenomenon in conjunction with primary PCI.

Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy

Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.

Techniques to Treat Slow-Flow/No-Reflow During Primary Percutaneous Coronary Intervention

OBJECTIVE

The aim of this study was to compare TIMI flow after administering intracoronary (IC) medications through various routes for the treatment of slow flow/no-reflow during primary PCI.

METHODS

Two independent parallel cohorts of the patients who underwent primary PCI for STEMI and developed slow/no-reflow were recruited. Selection of cohort was based on the route of administration of IC medications as proximal or distal. Post administration TIMI follow was compared between the two cohorts.

RESULTS

A total of 100 patients were included in both, proximal and distal, cohort. Distribution of angiographic, clinical and demographic characteristics was not significant between the two cohorts except prevalence of hypertension, and diabetes mellitus. Frequency of hypertension, and diabetes mellitus were 45 % vs.70 %; p < 0.001 and 28 % vs. 44 %; p = 0.018 among patients in distal and proximal cohort respectively. Final TIMI III flow was achieved in significantly higher number of patients in distal cohort with the frequency of 88 % vs. 76 %; p = 0.027 as compared to proximal cohort.

CONCLUSION

Administration of IC medication via distal route is observed to be more effective for the treatment of slow flow/no-reflow during primary PCI. Distal route via export catheter or perforated balloon technique should be preferred wherever feasible.

Intracoronary Administration of Drugs in Clinical Practice

Intracoronary administration of drugs allows to achieve the fastest possible effect in interventional cardiology. This allows to avoid all the biological filters of the body and achieve the required concentration of the active substance at the injection site. Also, given the local action, systemic side effects are nearly absent. The aim. To study the literature data of the leading countries of the world in the field of intracoronary drug administration. To analyze the experience of different centers on the use of various medications in the treatment of the phenomenon of distal microembolization. Results. One of the first drugs administered intracoronary was streptokinase for the treatment of acute myocardial infarction. After that, it became clear that this method of delivering drugs is possible and can be used. With the beginning of the treatment of acute coronary syndromes by stenting, one of the possible complications arose in the form of no-reflow. At the same time, realizing that this is a local problem, they began to use the possibility of intracoronary administration of drugs to treat this phenomenon. The main advantage of this method is quick response to drug administration. Today, the drugs of choice in the treatment of no-reflow are verapamil, adenosine, nitroprusside, adrenaline. On the other hand, probably the most common drug that is administered intracoronary is nitroglycerin. It is used as a vasodilator in the event of spasm of the coronary arteries. Subsequently, it has been recommended to deliver drugs via a microcatheter or aspiration catheter to achieve even more selective effect in the area of the affected vessel, and this also minimizes drug loss due to coronary reflux into the aortic sinuses while usinga guiding catheter. Work is also underway on the use of intracoronary insulin in acute coronary syndrome in order to reduce the area of damage in myocardial infarction. It is also very promising to study the introduction of stem cells directlyinto the myocardium through a microcatheter in order to regenerate the myocardium after a heart attack. Conclusions. Intracoronary administration of drugs allows to achieve the maximum effect in the shortest possible time. Today, many drugs can be used in this way, starting from the treatment of the phenomenon of distal microembolization and ending with myocardial regeneration after myocardial infarction.

“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.