Yanagawa Bobby, Mazine Amine, Bhatt Deepak L, Clavel Marie-Annick, Côté Nancy, Cheema Asim N, Pibarot Philippe, Verma Subodh
aDivision of Cardiac Surgery bDivision of Cardiology, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada cQuébec Heart and Lung Institute, Université Laval, Quebec City, Quebec dBrigham and Women's Hospital Heart and Vascular Center, Harvard Medical School, Boston, Massachusetts, USA.
Curr Opin Cardiol. 2017 Mar;32(2):137-146. doi: 10.1097/HCO.0000000000000373.
A recently published study has alerted the cardiovascular community to the existence of a significant and previously unrecognized risk of subclinical valve thrombosis following implantation of surgical and catheter-based bioprosthetic valves. The purpose of this article is to review our current understanding of this new clinical entity and to identify unanswered questions and areas for future research.
Subclinical bioprosthetic valve thrombosis (BPVT) is a more common phenomenon than previously appreciated. It appears that the incidence of BPVT is higher following transcatheter aortic valve replacement compared with surgical aortic valve replacement. Four-dimensional computed tomography (CT) is the most sensitive imaging modality for detection of leaflet immobility and subclinical BPVT. Certain echocardiographic findings, such as increasing transaortic gradients, increased cusp thickness and abnormal cusp mobility, predict the presence of BPVT on four-dimensional CT. There is a growing body of evidence linking subclinical BPVT with premature valvular hemodynamic deterioration and structural valve degeneration. Furthermore, subclinical leaflet thrombosis may constitute a nidus for unrecognized subacute cerebral or other thromboembolic events. Oral anticoagulation seems effective in both the prevention and treatment of BPVT.
Subclinical valve thrombosis is an important and underappreciated cause of early bioprosthetic valve failure. Although several recent studies have improved our understanding of this newly recognized clinical entity, a number of questions remain unanswered. Further studies are warranted to elucidate the true incidence of subclinical BPVT, its clinical consequences, as well as the optimal antithrombotic regimen following bioprosthetic valve implantation. The subgroups of patients at highest risk of BPVT will need to be identified for risk stratification purposes. Several ongoing clinical trials will shed some light on these important issues.
最近发表的一项研究提醒心血管领域注意，在植入外科生物瓣膜和经导管生物瓣膜后，存在一种重大且此前未被认识到的亚临床瓣膜血栓形成风险。本文的目的是回顾我们目前对这一新临床实体的认识，并确定未解决的问题和未来研究的领域。
亚临床生物瓣膜血栓形成（BPVT）是一种比之前认识到的更为常见的现象。与外科主动脉瓣置换相比，经导管主动脉瓣置换术后BPVT的发生率似乎更高。四维计算机断层扫描（CT）是检测瓣叶活动度和亚临床BPVT最敏感的成像方式。某些超声心动图表现，如经主动脉梯度增加、瓣叶厚度增加和瓣叶活动异常，可预测四维CT上BPVT的存在。越来越多的证据表明亚临床BPVT与瓣膜血流动力学过早恶化和瓣膜结构退变有关。此外，亚临床瓣叶血栓可能是未被认识到的亚急性脑或其他血栓栓塞事件的病灶。口服抗凝似乎对BPVT的预防和治疗都有效。
亚临床瓣膜血栓形成是早期生物瓣膜失效的一个重要但未得到充分认识的原因。尽管最近的几项研究增进了我们对这一新认识的临床实体的理解，但仍有一些问题未得到解答。有必要进行进一步研究，以阐明亚临床BPVT的真实发生率、其临床后果，以及生物瓣膜植入后的最佳抗血栓治疗方案。为了进行风险分层，需要确定BPVT风险最高的患者亚组。正在进行的几项临床试验将为这些重要问题提供一些线索。
