Clinical Policy: Emergency Department Management of Patients Needing Reperfusion Therapy for Acute ST-Segment Elevation Myocardial Infarction

Morphine timing-dependent modulation of TRPV1 phosphorylation correlates with differential morphine effects on myocardial ischemia/reperfusion injury

Opioids are used for pain relief in patients suffering from acute myocardial ischemia or infarction. Clinical and laboratory studies demonstrate that morphine treated patients or the experimental animal model suffering acute myocardial ischemia and reperfusion, may worsen myocardial viability. As transient receptor potential vanilloid 1 (TRPV1) plays important roles in pain sensation and cardio-protection, we query whether opioids may exacerbate myocardial viability via interaction with TRPV1 activity in the pain relief. We found the co-expressions of TRPV1 and opioid μ, δ and κ receptors in adult rat cardiomyocytes. Intravenous injection of morphine (0.3 mg/kg) at 20 min after induction of myocardial ischemia, in the rat model of acute myocardial ischemia and reperfusion, induced significant reduction of phosphorylated TRPV1 (p-TRPV1) in the ventricular myocardium and increase in serum cardiac troponin I (cTnI), compared with the ischemia/reperfusion controls (all P < 0.05). The effects of morphine were completely reversed by selective opioid μ, δ and κ receptor antagonists. While significant upregulation of p-TRPV1 (P < 0.05) and improvement of ±dP/dt max (all P < 0.05) were detected in the animals giving the same dose of morphine before induction of myocardial ischemia. The changes in p-TRPV1 correlate with the alterations of cTnI (r = -0.5840, P = 0.0283) and ±dP/dt max (r = 0.8084, P = 0.0005 and r = -0.8133, P = 0.0004, respectively). The findings of this study may indicate that potentiation and attenuation of TRPV1 sensitivity correlate with the improvement of the cardiac performance and the aggravation of myocardial viability, respectively, by giving morphine before and during myocardial ischemia and reperfusion.

FRET cascade miRNA addition probe from non-crosstalk DNA photonic wire assisted with clustering algorithm for early diagnosis of acute myocardial infarction

Early and accurate diagnosis of acute myocardial infarction (AMI) can significantly reduce patient mortality. A variety of miRNAs are found to dysregulate in AMI patients, but the up- or down-regulation of a specific miRNA may not be evident in the early stage, making it difficult to achieve accurate diagnosis. Here, proposing the design that DNA photonic wire (PW) with no spectral crosstalk would make an excellent template for miRNA conjoint analysis, we report the construction of a miRNA addition probe for the additive analysis of two up-regulated miRNAs (miR-133a and miR-208a) for early diagnosis of AMI in clinical serum samples. A three-dye non-crosstalk DNA PW is built to form the two-step fluorescence resonance energy transfer (FRET) cascade system, in which three paths can blocking the FRET cascade for separate or additive analysis of the two miRNAs. K-Means clustering algorithm is further utilized to classify the output signals of the miRNA addition probe, achieving a 100% accurate diagnosis of early AMI in both the training (n = 40) and validation (n = 19) cohorts of clinical serum samples.

Impact of timing of morphine treatment on infarct size in experimental animal model of acute myocardial ischemia and reperfusion

Morphine is generally used in clinical treatment for the patients who have not been effectively alleviated for chest pain after the treatment with nitrites or who contraindicate nitrite drugs. However, it was reported that the treatment with morphine in acute myocardial infarction or acute coronary artery syndromes induced increase in myocardial injury even increase of the mortality of the patients. After comparing the reported laboratory studies showing the cardioprotective effects and the clinical observations presenting the harmful consequences, we query whether the timing of the morphine treatment makes the difference in the prognosis of the ischemic/infarct myocardium. We found that intravenous injections of morphine (0.3 mg/kg) at 15 min before the acute myocardial ischemia, at 5 min and 20 min or 60 min after ligation of the coronary artery in separate groups of rats scheduled for acute myocardial ischemia, for 30 min or 90 min followed by reperfusion for 120 min, induced different results, reduction in the size of infarction, no effect and increases of the infarct sizes, respectively. The opioid μ- and kappa-receptors mediated the detrimental effect of morphine on the myocardial injury. The findings of this study suggest that administration of morphine may cause different consequences when used at different time in the pathology of acute myocardial ischemia and reperfusion. The underlying mechanisms in the pathology of acute myocardial ischemia warrant further study.

Three Cases of Emergency Department Medical Malpractice Involving "Consultations": How Is Liability Legally Determined?

This article presents three successfully litigated medical malpractice cases involving emergency physicians and consultants. We discuss the respective case medical diagnoses, as well as established legal principles that determine in a court proceeding which provider will be liable. Specifically, we explain the legal principles of “patient physician relationship” and “affirmative act.”

Critical appraisal of guidelines for coronary artery disease on dual antiplatelet therapy: More consensus than controversies

BACKGROUND

Dual antiplatelet therapy (DAPT) in the form of aspirin plus a P2 Y12 inhibitor, when indicated, is one of the key treatments in coronary artery disease (CAD). Many recommendations on DAPT in patients with CAD based on current guidelines are largely inconsistent. In our current study, we aimed at systematically reviewing DAPT-relevant clinical practice guidelines, and highlighting their commonalities and differences for better informed decision-making.

METHODS

Contemporary guidelines in English were searched in MEDLINE, Embase and websites of guideline organizations and professional societies. Guidelines with recommendations on DAPT for CAD patients were included. Guideline quality was appraised with the 6-domain Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument. The reporting of conflicts of interest (COI) was assessed individually with supplementary items from the RIGHT (Reporting Item for Practice Guidelines in Healthcare) checklist. Meanwhile, extraction of recommendations was performed.

RESULTS

A total of 18 guidelines fulfilled our inclusion criteria. Most of them were graded with relatively good scores averaging from 42% to 74%. Domains for lower scores were in "stakeholder involvement" and "application." The reporting of COI was satisfactory. For the recommendations on DAPT, most guidelines with high AGREE II scores included consistent recommendations on the timing and P2 Y12 inhibitor selection. Nonetheless, conflicts still exist on the duration of DAPT.

CONCLUSIONS

Quality of guidelines for DAPT in CAD was relatively high, though defects existed in "Applicability" and "Stakeholder Involvement." As these guidelines developed, DAPT recommendations gradually converged on a consensus. Clinical decision should be made on an individual basis.