Advances in magnetic resonance imaging of the myocardial area at risk and salvage

No abstract available

Risk stratification in non-ST elevation acute coronary syndromes: risk scores, biomarkers and clinical judgment

Undifferentiated chest pain is one of the most common reasons for emergency department attendance and admission to hospitals. Non-ST elevation acute coronary syndrome (NSTE-ACS) is an important cause of chest pain, and accurate diagnosis and risk stratification in the emergency department must be a clinical priority. In the future, the incidence of NSTE-ACS will rise further as higher sensitivity troponin assays are implemented in clinical practice. In this article, we review contemporary approaches for the diagnosis and risk stratification of NSTE-ACS during emergency care. We consider the limitations of current practices and potential improvements. Clinical guidelines recommend an early invasive strategy in higher risk NSTE-ACS. The Global Registry of Acute Coronary Events (GRACE) risk score is a validated risk stratification tool which has incremental prognostic value for risk stratification compared with clinical assessment or troponin testing alone. In emergency medicine, there has been a limited adoption of the GRACE score in some countries (e.g. United Kingdom), in part related to a delay in obtaining timely blood biochemistry results. Age makes an exponential contribution to the GRACE score, and on an individual patient basis, the risk of younger patients with a flow-limiting culprit coronary artery lesion may be underestimated. The future incorporation of novel cardiac biomarkers into this diagnostic pathway may allow for earlier treatment stratification. The cost-effectiveness of the new diagnostic pathways based on high-sensitivity troponin and copeptin must also be established. Finally, diagnostic tests and risk scores may optimize patient care but they cannot replace patient-focused good clinical judgment

How to mend a broken heart?

No abstract available

Connectivity for bridge-addable monotone graph classes

A class A of labelled graphs is bridge-addable if for all graphs G in A and all vertices u and v in distinct connected components of G, the graph obtained by adding an edge between u and u is also in A; the class A is monotone if for all G in A and all subgraphs H of G, H is also in A. We show that for any bridge-addable, monotone class A whose elements have vertex set 1,...,n, the probability that a uniformly random element of A is connected is at least (1-o_n(1)) e^{-1/2}, where o_n(1) tends to zero as n tends to infinity. This establishes the special case of a conjecture of McDiarmid, Steger and Welsh when the condition of monotonicity is added. This result has also been obtained independently by Kang and Panagiotiou (2011).Comment: 11 page

Stable coronary syndromes: pathophysiology, diagnostic advances and therapeutic need

The diagnostic management of patients with angina pectoris typically centres on the detection of obstructive epicardial CAD, which aligns with evidence-based treatment options that include medical therapy and myocardial revascularisation. This clinical paradigm fails to account for the considerable proportion (approximately one-third) of patients with angina in whom obstructive CAD is excluded. This common scenario presents a diagnostic conundrum whereby angina occurs but there is no obstructive CAD (ischaemia and no obstructive coronary artery disease—INOCA). We review new insights into the pathophysiology of angina whereby myocardial ischaemia results from a deficient supply of oxygenated blood to the myocardium, due to various combinations of focal or diffuse epicardial disease (macrovascular), microvascular dysfunction or both. Macrovascular disease may be due to the presence of obstructive CAD secondary to atherosclerosis, or may be dynamic due to a functional disorder (eg, coronary artery spasm, myocardial bridging). Pathophysiology of coronary microvascular disease may involve anatomical abnormalities resulting in increased coronary resistance, or functional abnormalities resulting in abnormal vasomotor tone. We consider novel clinical diagnostic techniques enabling new insights into the causes of angina and appraise the need for improved therapeutic options for patients with INOCA. We conclude that the taxonomy of stable CAD could improve to better reflect the heterogeneous pathophysiology of the coronary circulation. We propose the term ‘stable coronary syndromes’ (SCS), which aligns with the well-established terminology for ‘acute coronary syndromes’. SCS subtends a clinically relevant classification that more fully encompasses the different diseases of the epicardial and microvascular coronary circulation

Reference invasive tests of microvascular injury in myocardial infarction

No abstract available

An investigation into the polyethylene extrudates produced by simultaneous orientation and high temperature quenching

An apparatus was designed and constructed to allow a molten polymer extrudate under tension - or draw-down - to pass through a volume of liquid metal alloy in order that the extrudate would rapidly reach the temperature of the metal and be fully quenched on leaving the medium. The temperature of the medium could be controlled to an accuracy of +/- 0.5°C and the molten extrudates could be subjected to a wide range of draw-downs whilst maintaining a continuous production of extrudate. High density polyethylene (HOPE) extrudates were prepared from three dies - circular, strip and flat-film - at a range of liquid metal alloy temperatures (111 - 123°C) and over a wide range of draw-downs. The effect of processing on the HOPE extrudates was analysed by tensile testing, cyclic strain recovery, shrinkage testing, density measurements and annealing in air and liquid metal at 117°C. It was found that the level of draw-down and the temperature of the quenching medium had a profound effect upon the resultant properties of the extrudate. Extrudates prepared using a low level of orientation and low bath temperature are similar to those quenched in air, i.e. having a pronounced yield point, whereas those prepared using a high level of orientation and a high bath temperature exhibited properties similar to those of amorphous samples, i.e. high modulus and low extension at break. However, if the extrudate remains in the bath longer than is necessary to quench it, this effect is reversed. A possible mechanism was proposed to explain the relationship between the values of the processing parameters used, the morphology of the resultant HDPE extrudates and their properties

Stable coronary syndromes: the case for consolidating the nomenclature of stable ischemic heart disease

No abstract available

Meta-analysis of death and myocardial infarction in the DEFINE-FLAIR and iFR-SWEDEHEART trials: a hypothesis generating note of caution

In patients with coronary heart disease, revascularization can improve symptoms and in certain high-risk subgroups may improve prognosis. Coronary angiography provides anatomical information and the physiological significance of a stenosis can be determined using fractional flow reserve (FFR). Decisions on the need for and mode of revascularization can be optimized using FFR, however this involves administering adenosine to induce hyperemia. Generally, this test is well tolerated, but in some healthcare systems adenosine is either not licensed, unavailable, or expensive, limiting the use of FFR-guided management