Interventional Cardiology Review最新文献

筛选
英文 中文
Late Coronary-cameral Fistula Formation Between Circumflex Coronary Artery and Left Atrial Appendage Following Implantation of an Amulet Closure Device. 植入护身符封闭装置后,旋冠动脉与左房耳间晚期冠状-摄膜瘘形成。
IF 0.2
Interventional Cardiology Review Pub Date : 2025-02-28 eCollection Date: 2025-01-01 DOI: 10.15420/icr.2024.36
Timothy John Bagnall, Christopher James Broyd, David Hildick-Smith
{"title":"Late Coronary-cameral Fistula Formation Between Circumflex Coronary Artery and Left Atrial Appendage Following Implantation of an Amulet Closure Device.","authors":"Timothy John Bagnall, Christopher James Broyd, David Hildick-Smith","doi":"10.15420/icr.2024.36","DOIUrl":"10.15420/icr.2024.36","url":null,"abstract":"<p><p>An 80-year-old patient presented with a rare complication: a late coronary-cameral fistula following implantation of an Amulet (Abbott) left atrial appendage occlusion device. Microperforations from the device's anchoring tines have previously been suggested as a possible mechanism of fistula formation, a complication reported in two other cases. We propose an alternative theory of potential collateralisation of the threatened appendage from the nearby circumflex artery.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"20 ","pages":"e05"},"PeriodicalIF":0.2,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11934119/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143711510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Incidence and Pathology of Aortic Regurgitation. 主动脉反流的发生率和病理。
IF 0.2
Interventional Cardiology Review Pub Date : 2025-02-28 eCollection Date: 2025-01-01 DOI: 10.15420/icr.2024.37
Lucas Uchoa de Assis, Giulio M Mondellini, Mark Mp van den Dorpel, Jenna van Niekerk, Nicolas M Van Mieghem
{"title":"Incidence and Pathology of Aortic Regurgitation.","authors":"Lucas Uchoa de Assis, Giulio M Mondellini, Mark Mp van den Dorpel, Jenna van Niekerk, Nicolas M Van Mieghem","doi":"10.15420/icr.2024.37","DOIUrl":"10.15420/icr.2024.37","url":null,"abstract":"<p><p>Aortic regurgitation (AR) is the third most common valvular heart disease, with its prevalence and severity increasing with age. AR can arise from degenerative, congenital, inflammatory and infectious aetiologies, manifesting as primary AR with intrinsic leaflet disease, secondary AR due to aortopathy or annular dilatation, or a combination. Furthermore, AR can be acute, as observed in endocarditis and aortic dissection, or chronic, as seen in calcific aortic valve disease, connective tissue disorders, or bicuspid valve phenotypes. This review discusses the aetiopathology of these various AR manifestations (primary, secondary, acute and chronic AR), highlighting diagnostic challenges and implications for aortic valve replacement and transcatheter aortic valve implantation.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"20 ","pages":"e07"},"PeriodicalIF":0.2,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11934125/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143711504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Patent Foramen Ovale Closure: British Cardiovascular Intervention Society Position Statement. 卵圆孔未闭闭合:英国心血管介入学会立场声明。
IF 0.2
Interventional Cardiology Review Pub Date : 2025-02-19 eCollection Date: 2025-01-01 DOI: 10.15420/icr.2024.18
Mark Turner, Suneil K Aggarwal, Michael J Mullen, Iqbal Malik, Philip MacCarthy, David Northridge, Mark S Spence, Bushra Rana, David Hildick-Smith
{"title":"Patent Foramen Ovale Closure: British Cardiovascular Intervention Society Position Statement.","authors":"Mark Turner, Suneil K Aggarwal, Michael J Mullen, Iqbal Malik, Philip MacCarthy, David Northridge, Mark S Spence, Bushra Rana, David Hildick-Smith","doi":"10.15420/icr.2024.18","DOIUrl":"https://doi.org/10.15420/icr.2024.18","url":null,"abstract":"<p><p>The foramen ovale is a flap in the atrial septum that is open in the fetus to allow oxygenated blood returning from the placenta to pass to the systemic circulation. In early life, the primum septal flap should close, but in 25% of people the flap does not seal fully. Most patent foramen ovale (PFO) are small and open only following Valsalva. Resting right-to-left shunts are less common, occurring in 5% of individuals. This British Cardiovascular Intervention Society position statement describes the diagnosis, indications and procedure for PFO closure.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"20 ","pages":"e04"},"PeriodicalIF":0.2,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11904416/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143626377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Gadolinium-guided Transcatheter Aortic Valve Implantation in a Patient with Renal Impairment and a History of Severe Allergic Reaction to Iodinated Contrast Media. 钆引导下经导管主动脉瓣植入术治疗肾功能不全且对碘造影剂有严重过敏反应的患者。
IF 0.2
Interventional Cardiology Review Pub Date : 2025-02-18 eCollection Date: 2025-01-01 DOI: 10.15420/icr.2024.15
Bandar Alshehri, Hussein Alamri, Naif Alghasab, Jamal Ahmed, Fahad Alshehri, Sondos Samargandy, Abdulrahman M Almoghairi
{"title":"Gadolinium-guided Transcatheter Aortic Valve Implantation in a Patient with Renal Impairment and a History of Severe Allergic Reaction to Iodinated Contrast Media.","authors":"Bandar Alshehri, Hussein Alamri, Naif Alghasab, Jamal Ahmed, Fahad Alshehri, Sondos Samargandy, Abdulrahman M Almoghairi","doi":"10.15420/icr.2024.15","DOIUrl":"https://doi.org/10.15420/icr.2024.15","url":null,"abstract":"<p><p>Iodinated contrast media is integral to the evaluation for transcatheter aortic valve implantation; however, some patients may have contraindications to the use of iodinated contrast media. The study reports successful use of a gadolinium-based contrast agent in a patient with severe symptomatic aortic stenosis, contrast allergy and post-contrast acute kidney injury.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"20 ","pages":"e03"},"PeriodicalIF":0.2,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11865668/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Calcified Coronary Artery Disease: Pathology, Prevalence, Predictors and Impact on Outcomes. 钙化冠状动脉疾病:病理学、患病率、预测因素和对结果的影响
IF 0.2
Interventional Cardiology Review Pub Date : 2025-02-14 eCollection Date: 2025-01-01 DOI: 10.15420/icr.2024.20
Angela McInerney, Seán O Hynes, Nieves Gonzalo
{"title":"Calcified Coronary Artery Disease: Pathology, Prevalence, Predictors and Impact on Outcomes.","authors":"Angela McInerney, Seán O Hynes, Nieves Gonzalo","doi":"10.15420/icr.2024.20","DOIUrl":"https://doi.org/10.15420/icr.2024.20","url":null,"abstract":"<p><p>Calcified coronary artery disease is a common clinical finding and is visible angiographically in 25-30% of patients presenting for percutaneous coronary intervention. The presence of coronary calcium, even without coronary artery obstruction, confers an adverse clinical prognosis. Coronary calcium score on CT is additive in predicting risk of cardiovascular events beyond traditional scoring systems. Deposition of calcium in coronary arteries is initiated by the formation of an atherosclerotic plaque. Thereafter, multiple processes and pathways are involved, resulting in initial microcalcifications that coalesce into calcium sheets. Calcified nodules are thought to occur from rupture of these sheets. Calcified coronary stenoses requiring revascularisation result in greater target lesion failure and overall major adverse cardiovascular events than noncalcified lesions, regardless of the mode of revascularisation. Modifying calcium prior to stenting to optimise stent expansion is required and intracoronary imaging can greatly facilitate not only the detection of coronary calcium, but also the confirmation of adequate modification and stent optimisation. In this review, the authors examine the pathophysiology, prevalence, predictors and impact on outcomes of coronary calcium.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"20 ","pages":"e02"},"PeriodicalIF":0.2,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11865672/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Percutaneous Coronary Intervention in the UK: Recommendations of the British Cardiovascular Intervention Society. 英国经皮冠状动脉介入治疗:英国心血管介入协会的建议。
IF 0.2
Interventional Cardiology Review Pub Date : 2025-01-23 eCollection Date: 2025-01-01 DOI: 10.15420/icr.2024.43
Nick Curzen, Helen Routledge, Samuel McGrath, Mohamed Abouelasaad, Mamas Mamas, Tim Kinnaird, Rasha Al-Lamee, Peter O'Kane, Gerald Clesham, Dan McKenzie, James Nolan, Shrilla Banerjee, Clare Appleby, Adrian Banning, Douglas F Muir, James Spratt, Ellie Gudde, Sarah Carson, Suneil Aggarwal, John Irving, Vinoda Sharma, Ian Purcell, Azfar Zaman, David Hildick-Smith
{"title":"Percutaneous Coronary Intervention in the UK: Recommendations of the British Cardiovascular Intervention Society.","authors":"Nick Curzen, Helen Routledge, Samuel McGrath, Mohamed Abouelasaad, Mamas Mamas, Tim Kinnaird, Rasha Al-Lamee, Peter O'Kane, Gerald Clesham, Dan McKenzie, James Nolan, Shrilla Banerjee, Clare Appleby, Adrian Banning, Douglas F Muir, James Spratt, Ellie Gudde, Sarah Carson, Suneil Aggarwal, John Irving, Vinoda Sharma, Ian Purcell, Azfar Zaman, David Hildick-Smith","doi":"10.15420/icr.2024.43","DOIUrl":"10.15420/icr.2024.43","url":null,"abstract":"<p><p>Percutaneous techniques to treat obstructive coronary artery disease continue to evolve and the evidence base informing our practice is shared and summarised in international guidelines. In the UK, the British Cardiovascular Intervention Society represents and supports interventional cardiologists undertaking both coronary and structural interventions. Procedural data are collected in a national registry and these inform our understanding of UK practice and outcomes. These recommendations, pertaining to coronary intervention alone, are an update of those published in 2015 and describe the provision of percutaneous coronary intervention in the UK intended to provide optimal patient care.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"20 ","pages":"e01"},"PeriodicalIF":0.2,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11904421/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143626384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Management of Stent Underexpansion and Aorto-ostial Lesions. 支架扩张不足和主动脉-口病变的处理。
IF 0.2
Interventional Cardiology Review Pub Date : 2024-12-23 eCollection Date: 2024-01-01 DOI: 10.15420/icr.2024.10
Luca Paolucci, Asad Shabbir, Marco Lombardi, Adrián Jerónimo, Javier Escaned, Nieves Gonzalo
{"title":"Management of Stent Underexpansion and Aorto-ostial Lesions.","authors":"Luca Paolucci, Asad Shabbir, Marco Lombardi, Adrián Jerónimo, Javier Escaned, Nieves Gonzalo","doi":"10.15420/icr.2024.10","DOIUrl":"10.15420/icr.2024.10","url":null,"abstract":"<p><p>Stent underexpansion (SU) and aorto-ostial lesions (AOL) are challenging conditions commonly faced during clinical practice in the setting of percutaneous coronary interventions. Compared to other interventional settings, both SU and AOL are associated with an increased risk of immediate and late events following percutaneous coronary intervention. Several specific strategies including the systematic use of intracoronary imaging and dedicated techniques for lesions' preparation and calcium debulking have been described. This narrative review summarises the currently available options for the diagnosis and treatment of both SU and AOL, highlighting the potential benefits and limits of each technique in these specific settings.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"19 ","pages":"e26"},"PeriodicalIF":0.2,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11770534/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143053756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Coronary Artery Ectasia in Acute Coronary Syndrome: The Role of Non-vitamin K Antagonist Oral Anticoagulants in Management. 急性冠脉综合征冠状动脉扩张:非维生素K拮抗剂口服抗凝剂在治疗中的作用。
IF 0.2
Interventional Cardiology Review Pub Date : 2024-11-27 eCollection Date: 2024-01-01 DOI: 10.15420/icr.2024.25
Mahmoud Izraiq, Nail Alshoubaki, Omran A Abu-Dhaim, Raed Aqel
{"title":"Coronary Artery Ectasia in Acute Coronary Syndrome: The Role of Non-vitamin K Antagonist Oral Anticoagulants in Management.","authors":"Mahmoud Izraiq, Nail Alshoubaki, Omran A Abu-Dhaim, Raed Aqel","doi":"10.15420/icr.2024.25","DOIUrl":"https://doi.org/10.15420/icr.2024.25","url":null,"abstract":"<p><p>Coronary artery ectasia (CAE) is an abnormal dilatation of coronary artery segments, often linked with atherosclerosis. This report discusses two cases of CAE presenting as acute coronary syndrome. A 36-year-old man had proximal blockage in the left circumflex artery (LCx) and ectasia in the obtuse marginal artery and left anterior descending artery (LAD), while a 53-year-old male smoker had an ectatic LAD with a substantial thrombus. Both were treated with dual antiplatelet therapy (aspirin and clopidogrel) and non-vitamin K antagonist oral anticoagulants (NOACs), specifically apixaban, along with atorvastatin. The first patient had complete resolution of LCx occlusion after 1 year, and the second patient had complete thrombus dissolution in the LAD in 2 months. These cases highlight the potential benefits of NOACs in managing CAE in acute coronary syndrome, suggesting that triple therapy can significantly improve clinical outcomes.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"19 ","pages":"e25"},"PeriodicalIF":0.2,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11702008/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144048725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Wire Escalation And De-escalation Techniques in Antegrade and Retrograde Approaches to Chronic Total Occlusion Percutaneous Coronary Interventions. 慢性全闭塞经皮冠状动脉介入治疗的顺、逆行入路中的钢丝升高和降低技术。
IF 0.2
Interventional Cardiology Review Pub Date : 2024-11-12 eCollection Date: 2024-01-01 DOI: 10.15420/icr.2024.14
Laura Novelli, Jorge Sanz-Sanchez, Gabriele Gasparini
{"title":"Wire Escalation And De-escalation Techniques in Antegrade and Retrograde Approaches to Chronic Total Occlusion Percutaneous Coronary Interventions.","authors":"Laura Novelli, Jorge Sanz-Sanchez, Gabriele Gasparini","doi":"10.15420/icr.2024.14","DOIUrl":"10.15420/icr.2024.14","url":null,"abstract":"<p><p>Coronary chronic total occlusions (CTO) are frequently identified during coronary angiography and remain the most challenging subset of coronary artery lesions to treat; however, advancements in techniques and materials have greatly improved success rates. Various crossing algorithms have been developed to standardise the approach to CTO interventions based on angiographic criteria. Antegrade wiring is typically the initial strategy of choice, particularly in cases of short and straight CTOs with tapered proximal cap. Similarly, retrograde crossing can be achieved through retrograde wiring, although this approach has a very low success rate. This review aims to outline how to perform a CTO analysis, clarify the fundamental features of guidewires and provide insights into both antegrade and retrograde wire-based approaches.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"19 ","pages":"e23"},"PeriodicalIF":0.2,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11622219/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142802458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
British Cardiovascular Intervention Society Training Culture Focus Group Position Statement: Bringing Trainees and Trainers Together. 英国心血管介入学会培训文化焦点小组立场声明:让受训者和培训师走到一起。
IF 0.2
Interventional Cardiology Review Pub Date : 2024-11-04 eCollection Date: 2024-01-01 DOI: 10.15420/icr.2024.07
Thomas R Gilpin, Holly Morgan, Christian Fielder Camm, Alexandra Moss, James Cotton, Raghav T Bhatia, Dan McKenzie, Rasha Al-Lamee, Simon Ray, Nick Curzen
{"title":"British Cardiovascular Intervention Society Training Culture Focus Group Position Statement: Bringing Trainees and Trainers Together.","authors":"Thomas R Gilpin, Holly Morgan, Christian Fielder Camm, Alexandra Moss, James Cotton, Raghav T Bhatia, Dan McKenzie, Rasha Al-Lamee, Simon Ray, Nick Curzen","doi":"10.15420/icr.2024.07","DOIUrl":"10.15420/icr.2024.07","url":null,"abstract":"<p><p>Unprofessional behaviour within cardiology has been well documented and commonly occurs within the cardiac catheterisation laboratory, with higher rates in interventional subspecialities. While most trainees have positive experiences and encounters within the catheterisation laboratory, around one in five report experiencing bullying. This not only has a significant negative impact on the individuals directly involved, but also on the wider multidisciplinary team; importantly, it will have a deleterious effect on patient safety. The British Cardiovascular Intervention Society established the Training Culture Focus Group in 2022 to analyse and offer potential solutions to this pressing issue. We recommend that a cohesive approach between trainers and trainees is the most effective way to reduce unprofessional behaviour incidents, thus improving departmental workplace culture and a subsequent reduction in adverse patient safety events.</p>","PeriodicalId":38586,"journal":{"name":"Interventional Cardiology Review","volume":"19 ","pages":"e22"},"PeriodicalIF":0.2,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11577867/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142683015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信