Department of Internal Medicine, Mayo Clinic and Foundation for Education and Research, Rochester, MN 55905, USA.
Arterioscler Thromb Vasc Biol. 2011 Nov;31(11):2760-6. doi: 10.1161/ATVBAHA.111.232991.
Left atrial blood stasis is associated with increased risk for left atrial appendage thrombus (LAAT) and stroke in atrial fibrillation (AF). Von Willebrand factor (VWF) is associated with thromboembolism in AF. VWF thrombogenic activity is proportional to multimer size, which is regulated by VWF-cleaving protease (ADAMTS13).
To assess the association between left atrial blood stasis and VWF-ADAMTS13 system, plasma VWF antigen (VWF:Ag), VWF activity (VWF:Act), and ADAMTS13 activity were measured in 414 consecutive patients with nonvalvular AF (age 63±13 years; 25% women) and in 100 patients (age 64±14 years; 39% women) with normal sinus rhythm. Spontaneous echocardiographic contrast (SEC), left atrial appendage emptying velocity, and LAAT were assessed by transesophageal echocardiography. Presence and intensity of SEC varied directly with VWF:Ag and VWF:Act but not with ADAMTS13 activity. AF patients with LAAT had higher VWF:Ag (200±61 versus 155±52, P=0.0006) and VWF:Act (179±57 versus 141±51 P=0.0026) compared with those without LAAT. VWF:Ag and VWF:Act were independent predictors of LAAT after adjustment for CHADS2 score (P=0.0179 and P=0.0497, respectively).
The association between VWF and SEC may explain the thrombotic propensity in AF. Elevated VWF:Ag may help identify AF patients at risk for LAAT.
左心房淤血与心房颤动（AF）中的左心耳血栓（LAAT）和中风风险增加有关。血管性血友病因子（VWF）与 AF 中的血栓栓塞相关。VWF 的血栓形成活性与多聚体大小成正比，而多聚体大小受 VWF 切割蛋白酶（ADAMTS13）调节。
为了评估左心房淤血与 VWF-ADAMTS13 系统之间的关系，在 414 例连续的非瓣膜性 AF 患者（年龄 63±13 岁；25%为女性）和 100 例窦性节律正常的患者（年龄 64±14 岁；39%为女性）中测量了血浆 VWF 抗原（VWF：Ag）、VWF 活性（VWF：Act）和 ADAMTS13 活性。通过经食管超声心动图评估自发性超声对比（SEC）、左心耳排空速度和 LAAT。SEC 的存在和强度与 VWF：Ag 和 VWF：Act 呈直接相关，但与 ADAMTS13 活性无关。与无 LAAT 的 AF 患者相比，LAAT 患者的 VWF：Ag（200±61 与 155±52，P=0.0006）和 VWF：Act（179±57 与 141±51，P=0.0026）更高。在调整 CHADS2 评分后，VWF：Ag 和 VWF：Act 是 LAAT 的独立预测因子（分别为 P=0.0179 和 P=0.0497）。
VWF 与 SEC 之间的关联可能解释了 AF 中的血栓形成倾向。VWF：Ag 升高可能有助于识别有 LAAT 风险的 AF 患者。
