Thrombosis in ST-elevation myocardial infarction: Insights from thrombi retrieved by aspiration thrombectomy

Multilevel hybrid accurate handcrafted model for myocardial infarction classification using ECG signals

Myocardial infarction (MI) is detected using electrocardiography (ECG) signals. Machine learning (ML) models have been used for automated MI detection on ECG signals. Deep learning models generally yield high classification performance but are computationally intensive. We have developed a novel multilevel hybrid feature extraction-based classification model with low time complexity for MI classification. The study dataset comprising 12-lead ECGs belonging to one healthy and 10 MI classes were downloaded from a public ECG signal databank. The model architecture comprised multilevel hybrid feature extraction, iterative feature selection, classification, and iterative majority voting (IMV). In the hybrid handcrafted feature (HHF) generation phase, both textural and statistical feature extraction functions were used to extract features from ECG beats but only at a low level. A new pooling-based multilevel decomposition model was presented to enable them to create features at a high level. This model used average and maximum pooling to create decomposed signals. Using these pooling functions, an unbalanced tree was obtained. Therefore, this model was named multilevel unbalanced pooling tree transformation (MUPTT). On the feature extraction side, two extractors (functions) were used to generate both statistical and textural features. To generate statistical features, 20 commonly used moments were used. A new, improved symmetric binary pattern function was proposed to generate textural features. Both feature extractors were applied to the original MI signal and the decomposed signals generated by the MUPTT. The most valuable features from among the extracted feature vectors were selected using iterative neighborhood component analysis (INCA). In the classification phase, a one-dimensional nearest neighbor classifier with ten-fold cross-validation was used to obtain lead-wise results. The computed lead-wise results derived from all 12 leads of the same beat were input to the IMV algorithm to generate ten voted results. The most representative was chosen using a greedy technique to calculate the overall classification performance of the model. The HHF-MUPTT-based ECG beat classification model attained excellent performance, with the best lead-wise accuracy of 99.85% observed in Lead III and 99.94% classification accuracy using the IMV algorithm. The results confirmed the high MI classification ability of the presented computationally lightweight HHF-MUPTT-based model.

Successful visible thrombus aspiration in ST-segment elevation myocardial infarction: associated factors and the clinical impact

BACKGROUND

Thrombus aspiration (TA) has been considered a procedure for controlling distal emboli and improving microvascular perfusion. However, current guidelines classify routine TA as class III recommendation, and it has been reported that the efficacy of TA is limited because of the relatively high incidence of failure in retrieval of thrombotic material. The aim of this study was to explore patient characteristics and procedural factors associated with successful TA in ST-elevation myocardial infarction (STEMI) and to assess the clinical impact of successful TA.

METHODS

This single-center retrospective study enrolled 158 STEMI patients who underwent TA as initial recanalization. Factors associated with successful TA, which was defined as retrieving any visible material by aspiration catheter, were explored, and angiographical and short-term outcomes were assessed.

RESULTS

In 146 cases (92.4%), the aspiration catheter reached the culprit lesion. Successful TA was achieved in 72 cases (45.6%). The single angiographical characteristic of successful TA was a higher Thrombolysis in Myocardial Infarction grade before TA. Among the procedural characteristics, the rate of successful TA was higher with a 7-French aspiration catheter compared with the rate with a 6-French catheter (57.1% vs. 29.9%, P  = 0.01). Thrombolysis in Myocardial Infarction grade 3 flow was more frequent in patients with successful TA immediately after TA (36.1% vs. 16.3%, P  = 0.006) and at final angiography (91.7% vs 79.1%, P  = 0.04) compared with the grade in patients without successful TA, respectively.

CONCLUSIONS

The use of a larger aspiration catheter may be effective in retrieving visible thrombus material, and successful TA led to better angiographical results.

Aspiration Thrombectomy

Distal embolization of thrombus can lead to impairment of microvascular perfusion, and measures of abnormal microvascular perfusion have been associated with increased mortality and worsened clinical outcomes. Large multicenter randomized controlled trials and multiple meta-analyses have failed to demonstrate an improvement in clinical outcomes with the routine use of manual aspiration thrombectomy, with some studies suggesting an increased incidence of stroke, likely owing to thrombus dislodgement during retrieval leading to cerebral vessel embolization. In patients with high thrombus burden who do not respond to balloon predilation, the use of manual aspiration thrombectomy as a bailout treatment strategy can be considered.

Acute myocardial infarction in adolescents: reappraisal of underlying mechanisms

Worldwide, a myocardial infarction (MI) is an important cause of death. Acute MI occurs most commonly at an older age. However, the incidence of acute MI in adolescents is increasing. This is partly due to an increase in cardiovascular risk factors (e.g. smoking, unhealthy diet), which might lead to premature atherosclerosis. However, several non-atherosclerotic causes of MI in adolescents are also described in the literature, such as vascular spasm due to the use of cocaine. We may assume that acute MI is not considered to be the most likely cause of chest pain in adolescents. Therefore, the risk of a dramatic outcome in this patient category may be significant. This point of view article addresses the pathophysiological process and subsequent diagnostic approach in adolescents with MI resulting from either premature atherosclerosis or of non-atherosclerotic causes. Insight into the potential operational mechanisms of the coronary artery incident may have a major impact on the clinical course following admission. We would like to underline that a personalised clinical approach remains of utmost importance in each patient treated by protocolised medicine. This is particularly true when acute MI occurs at a young age, since the underlying cause more frequently differs from the conventional atherosclerotic process in this patient category.

Thrombogenesis and thrombotic disorders based on 'two-path unifying theory of hemostasis': philosophical, physiological, and phenotypical interpretation

: Hemostasis, endowed to human to protect lives, is a process of logical blood clotting system to prevent blood loss in vascular injury. However, the notion that deadly thrombosis occurs as a result of normal hemostasis in intravascular injury could encounter with conceptual skepticism because the term 'thrombosis' automatically conjures up as serious disease. According to 'two-path unifying theory', normal hemostasis is initiated only by vascular injury through activated unusually large von Willebrand factor (ULVWF) path and/or activated tissue factor (TF) path. When these two equally important paths are unified in normal hemostasis, clotting at external bodily injury site is initiated for wound healing, but in intravascular injury 'blood clots' is formed to produce a disease called 'thrombosis'. As microthrombi from ULVWF path and fibrin clots from TF path become unified, macrothrombus would be formed via thrombogenesis. However, if ULVWF path and TF path cannot be unified due to lone ULVWF path activation, partial hemostasis produces only microthrombi seen in endotheliopathy-associated vascular microthrombotic disease. In real life, in-vivo fibrin clot cannot be formed alone via normal hemostasis because bleeding vascular injury always activates both ULVWF and TF paths. Without vascular injury, microthrombi due to activated ULVWF path occur in ADAMTS13 deficiency in thrombotic thrombocytopenic purpura, and fibrin clots due to activated TF path occur in acute promyelocytic leukemia. These two conditions can be called pathologic hemostasis. Three thrombogenic pathways produce three thrombotic disorders, which include macrothrombosis, microthrombosis and true DIC through macrothrombogenesis, microthrombogenesis and fibrinogenesis in both physiologic and pathological hemostasis.

New non-invasive indexes of arterial stiffness are significantly correlated with severity and complexity of coronary atherosclerosis

BACKGROUND

Endothelial dysfunction and increased arterial stiffness gradually develop before the manifestation of catastrophic cardiovascular events. Therefore, detection and assessment of vascular function are required to address pre-existing pathological conditions. However, the currently available diagnostic devices and methods are insufficient due to variability among investigators and the time-consuming nature of manual procedures.

METHODS

Recently, novel devices were developed for the detection of both arterial stiffness and endothelial dysfunction in a single blood pressure measurement using a cuff-oscillometric technique (AVE-1500, Shisei Datum, Japan). API (arterial pressure volume index) is defined as the reciprocal of the slope of the tangent of the brachial artery pressure-volume curve, and AVI (arterial velocity pulse index) is defined as the ratio of the difference between the ejection and reflection waves. In the present study, we performed retrospective, cross-sectional analyses of subjects (n = 102; mean age = 70.5 ± 10.4 years) with detailed coronary angiographic examinations and clinical background parameters.

RESULTS

After adjusting for various variables using multiple linear regression analyses, we found that API, but not AVI, was significantly correlated with coronary artery severity and complexity scores.

CONCLUSIONS

We propose that API may be a new vascular index useful for monitoring and assessing the severity and complexity of atherosclerosis in subjects with coronary artery disease and for evaluating atherosclerotic diseases.

Inhibitory effects of ASP6537, a selective cyclooxygenase-1 inhibitor, on thrombosis and neointima formation in rats

INTRODUCTION

Percutaneous coronary interventions (PCIs), such as balloon angioplasty and stent placement, are effective in the treatment of coronary artery disease. PCI has drawbacks, however, including acute thrombosis after the procedure and restenosis of the vascular lumen due to abnormal neointimal hyperplasia. ASP6537 is a selective COX-1 inhibitor that has been investigated as a possible candidate for clinical development as an antiplatelet agent. In the present study, we evaluated the in vivo antithrombotic effect of ASP6537 and its effect on neointima formation after balloon angioplasty.

MATERIAL AND METHODS

The antithrombotic effect of ASP6537 was examined using an arteriovenous shunt thrombosis model in rats while the effect of ASP6537 on neointima formation was evaluated in a rat carotid arterial balloon angioplasty model.

RESULTS

In the thrombosis study, ASP6537 dose-dependently decreased the protein content of the thrombus, while no prolongation of template bleeding time was observed. In the neointima study, ASP6537 reduced neointima formation.

CONCLUSIONS

ASP6537 may be a promising agent for the prevention of acute thrombosis and restenosis after PCI in place of aspirin.