Enhanced spontaneous thrombolysis: A new therapeutic challenge

Myocardial infarction with non-obstructive coronary arteries: Etiology, diagnosis, treatment and prognosis

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is responsible for 10% of myocardial infarctions. Previously, patients were thought to have good prognosis, but evidence-based management and treatment strategies were scarce. Today, researchers and physicians recognize MINOCA as a condition with non-trivial mortality and morbidity. Therapeutic strategies are highly dependent on the underlying disease mechanism in each patient. However, to reach a diagnosis of MINOCA, a multimodal approach is required and, even with an optimal work-up, the cause remains unknown in 8-25% of patients. Research has been growing and position papers from the European Society of Cardiology (ESC) and the American Heart Association/American College of Cardiology have been published, and MINOCA has been included in the more recent ESC guidelines on myocardial infarction. Nonetheless, some clinicians still assume that the absence of coronary obstruction excludes the possibility of acute myocardial infarction. Therefore, in the present paper, we aim to compile and present the available data on the etiology, diagnosis, treatment, and prognosis of MINOCA.

A valuable cardiac magnetic resonance investigation after MINOCA/takotsubo Syndrome: a case report

Myocardial infarction with non-obstructive coronary arteries is a working diagnosis that includes takotsubo cardiomyopathy/syndrome (TTS). Cardiac magnetic resonance (CMR) is useful for establishing the underlying aetiology of myocardial infarction with non-obstructive coronary arteries during the acute phase, but its role in follow-up is less well established. A 35-year-old man with several cardiac risk factors presented 3 days after his sister's death with biochemical and clinical features of acute myocardial infarction without coronary artery obstruction on angiography but with diagnostic features of TTS on CMR, including oedema but no late gadolinium enhancement. Subsequent CMR 3 months later revealed left ventricular late gadolinium enhancement suggesting previous acute myocardial infarction. Although the initial diagnosis of TTS was robust according to established criteria, it remained uncertain whether the later ischaemic injury was related to an ischaemic event at presentation or occurred in the intervening period. Nevertheless, CMR may have an extended role in the follow-up of these patients and may reveal additional, actionable pathology.

Mechanisms of action of metformin with special reference to cardiovascular protection

Management guidelines continue to identify metformin as initial pharmacologic antidiabetic therapy of choice for people with type 2 diabetes without contraindications, despite recent randomized trials that have demonstrated significant improvements in cardiovascular outcomes with newer classes of antidiabetic therapies. The purpose of this review is to summarize the current state of knowledge of metformin's therapeutic actions on blood glucose and cardiovascular clinical evidence and to consider the mechanisms that underlie them. The effects of metformin on glycaemia occur mainly in the liver, but metformin-stimulated glucose disposal by the gut has emerged as an increasingly import site of action of metformin. Additionally, metformin induces increased secretion of GLP-1 from intestinal L-cells. Clinical cardiovascular protection with metformin is supported by three randomized outcomes trials (in newly diagnosed and late stage insulin-treated type 2 diabetes patients) and a wealth of observational data. Initial evidence suggests that cotreatment with metformin may enhance the impact of newer incretin-based therapies on cardiovascular outcomes, an important observation as metformin can be combined with any other antidiabetic agent. Multiple potential mechanisms support the concept of cardiovascular protection with metformin beyond those provided by reduced blood glucose, including weight loss, improvements in haemostatic function, reduced inflammation, and oxidative stress, and inhibition of key steps in the process of atherosclerosis. Accordingly, metformin remains well placed to support improvements in cardiovascular outcomes, from diagnosis and throughout the course of type 2 diabetes, even in this new age of improved outcomes in type 2 diabetes.

Enhanced pre-operative thrombolytic status is associated with the incidence of deep venous thrombosis in patients undergoing total knee arthroplasty

Background

Deep venous thrombosis (DVT), which is often associated with pulmonary embolism (PE), is a serious complication after total knee arthroplasty (TKA). In the present study, we examined the overall thrombotic and thrombolytic status using Global Thrombosis Test (GTT) in non-anticoagulated blood of patients undergoing TKA to develop the predictable marker for the incidence of DVT.

Methods

DVT was diagnosed using doppler ultrasonography a day after the surgery in 31 patients with osteoarthritis (n = 24), rheumatoid arthritis (n = 6) and ankylosing spondylitis (n = 1) by the well-trained operator. We measured overall thrombotic and thrombolytic status using GTT and other biomarkers, which is associated with blood coagulation and fibrinolysis, before and immediately after the surgery.

Results

Newly-generated DVT during the operation was detected in 11 of 31 patients (35.4%) 1 day after TKA. There were no differences in markers of coagulation (PT and APTT), platelet activity (platelet aggregation-induced by ADP and collagen) and fibrinolysis (FDP and D-dimer) between non-DVT and DVT group both before and after the surgery. Both Pre- and Post-operative GTT-occlusion times (OT), an index of platelet reactivity, were tended to be shorter, but not significant, in DVT group compared with non-DVT group. Pre-operative GTT-lysis time (LT), an index of thrombolytic activity, was significantly shorter in DVT group compared with non-DVT group, while there were no differences in post-operative value of this index between DVT group and non-DVT group, suggesting overall thrombolytic activity was enhanced in DVT group before surgery.

Conclusions

Our data suggest that enhancement of pre-operative thrombolytic activity assessed by GTT may be a predictable marker for the incidence of DVT after TKA.

Juxtacortical spots on fluid-attenuated inversion recovery images in cryptogenic transient ischemic attack

Background and Purpose

Juxtacortical spots are detected frequently on fluid-attenuated inversion recovery (FLAIR) images, but have not been extensively researched in patients with transient ischemic attack (TIA). We hypothesized that juxtacortical spots on FLAIR images are partly associated with right-to-left shunt (RLS) in TIA without clear etiology. The possibility of an association between the presence of RLS and juxtacortical spots on FLAIR images in patients with TIA without clear etiology was investigated, and the imaging findings of patients with and without RLS were compared.

Methods

This was a retrospective study of TIA patients who visited our tertiary stroke center consecutively within 72 hours of TIA onset. Cryptogenic TIA was defined as no clear etiology despite a routine diagnostic workup. The presence of RLS was examined by transcranial Doppler with an agitated saline test or transesophageal echocardiography. Juxtacortical spots were defined as small and round hyperintensities in the juxtacortex on FLAIR images, excluding white-matter hyperintensities.

Results

Of the 132 patients with cryptogenic TIA examined for this study, 70 (53.0%) had RLS. Juxtacortical spots on FLAIR images were detected more frequently in patients with RLS than in those without. The independent factors for the presence of juxtacortical spots were RLS [odds ratio (OR)=3.802, 95% confidence interval (95% CI)=1.74-8.2; p=0.001] and age (OR=1.058, 95% CI=1.01-1.10; p=0.004) by multivariate analysis. The number of juxtacortical spots was significantly higher among patients with a moderate-to-large RLS than in those with a small or no RLS.

Conclusions

The findings of the present study demonstrate a significant association between the presence of RLS and the occurrence of juxtacortical spots on FLAIR images in patients with cryptogenic TIA.

Mechanism of the experimental antithrombotic effect of some apple varieties involves enhanced endogenous thrombolytic activity

Prevention of arterial thrombotic diseases has high priority in developed countries. As inappropriate diet is known to enhance the risk for acute thrombotic events, a regular diet with experimentally proven antithrombotic effect might be a beneficial way of prevention. The present study is part of a series of investigations testing fruits and vegetables for antithrombotic activity. The Global Thrombosis Test was used to screen sixteen different apple varieties for antiplatelet and thrombolytic activities. The in vitro effective varieties were further investigated using the laser-induced thrombosis model in mice. In order to investigate the mechanism, hemostatometry and flow-mediated vasodilation test (FMV) were performed. Apple varieties were grouped into subclasses according to their antithrombotic activity. AP-2, AP-13, AP-14 and AP-15 showed significant antithrombotic effect both in vitro and in vivo. AP-8 was antithrombotic in vitro but could not determine in vivo because of the shortage of the sample. The antithrombotic effect was mainly due to activation of endogenous thrombolytic mechanism. The mechanism of such enhanced thrombolysis was investigated using a synthetic inhibitor highly specific to plasmin, polyclonal IgG to t-PA and u-PA, and testing the antithrombotic effect in t-PA knockout mice. Antithrombotic activity was prevented by the synthetic plasmin inhibitor and IgG against t-PA but not against u-PA. There was no antithrombotic activity in t-PA knockout mice. Intake of antithrombotic apple filtrate did not affect FMV and platelet reactivity. The antithrombotic effect was heat stable at 100 °C for 10 min. These results suggest that the mechanism of antithrombotic activity involves an increased t-PA release from the vascular endothelium and an inhibition of plasminogen activator inhibitor (PAI-1) release from activated platelets. The present findings justify including antithrombotic apple varieties in an antithrombotic diet.

Migraine aura pathophysiology: the role of blood vessels and microembolisation

Migraine attacks with auras are sometimes associated with underlying hereditary or acquired cerebrovascular disorders. A unifying pathophysiological explanation linking migraine to these conditions has been difficult to identify. On the basis of genetic and epidemiological evidence, we suggest that changes in blood vessels, hypoperfusion disorders, and microembolisation can cause neurovascular dysfunction and evoke cortical spreading depression, an event that is widely thought to underlie aura symptoms. In fact, recent experimental data have indicated that focal, mild, and transient ischaemia can trigger cortical spreading depression without an enduring tissue signature. Although migraine with aura has many causes (eg, neuronal network excitability), it seems that migraine and stroke might both be triggered by hypoperfusion and could therefore exist on a continuum of vascular complications in a subset of patients who have these hereditary or acquired comorbid vascular conditions.

Coronary thrombosis: In vivo, ex vivo and in vitro

Acute stent thrombosis remains one of the most important concerns in clinical cardiology. The mechanism is not fully understood but a prothrombotic state is a key component. We describe a case of acute stent thrombosis, within an hour of rescue angioplasty, despite use of full dose fibrinolytic (reteplase) and antiplatelet therapy (aspirin and clopidogrel). Risk of acute stent thrombosis was predicted an hour earlier, when the patient was clinically well, by a novel near-patient test of thrombotic and thrombolytic status (in vitro). Subsequent stent thrombosis was visualised angiographically (in vivo) and confirmed by extraction of the thrombus (ex vivo). The near-patient test sensitively detected reversal of the prothrombotic state after abciximab treatment. We believe this is the first description of the clinical use of a near-patient test within the cardiac catheterisation laboratory to predict risk of imminent stent thrombosis.

The antithrombotic effect of borneol related to its anticoagulant property

Borneol is consumed excessively in China and Southeast Asian countries particularly in combined formula for preventing cardiovascular disease, but few studies were conducted on its effects on thrombosis. In this study, the antithrombotic and antiplatelet activities of borneol were investigated on thrombosis in vivo and on platelet aggregation ex-vivo. In addition, the coagulation parameters and influence on fibrinolytic activity were also assessed. The results showed that borneol had concentration dependent inhibitory effects on arterio-venous shunt and venous thrombosis but no effect on ADP and AA-induced platelet aggregation. Meanwhile, borneol prolonged the coagulation parameters for prothrombin time (PT) and thrombin time (TT), but did not show any fibrinolytic activity. It suggested that the antithrombotic activity of borneol and its action in combined formula for preventing cardiovascular diseases might be due to anticoagulant activity rather than antiplatelet activity.