Department of Cardiovascular Medicine, Mayo Clinic Hospital, Rochester, Minnesota.
Center for Structural Heart Disease, Henry Ford Hospital, Detroit, Michigan.
JACC Cardiovasc Imaging. 2020 Sep;13(9):1945-1957. doi: 10.1016/j.jcmg.2020.03.013. Epub 2020 May 13.
This study aims to establish a computed tomography (CT)-based scoring system for grading mitral annular calcification (MAC) severity and potentially aid in predicting valve embolization during transcatheter mitral valve (MV) replacement using balloon-expandable aortic transcatheter heart valves.
Transcatheter MV replacement is emerging as an alternative treatment for patients with severe MAC who are not surgical candidates. Although cardiac CT is the imaging modality of choice in the evaluation of candidates for valve-in-MAC (ViMAC), a standardized grading system to quantify MAC severity has not been established.
We performed a multicenter retrospective review of cardiac CT and clinical outcomes of patients undergoing ViMAC. A CT-based MAC score was created using the following features: average calcium thickness (mm), degrees of annulus circumference involved, calcification at one or both fibrous trigones, and calcification of one or both leaflets. Features were assigned points according to severity (total maximum score = 10) and severity grade was assigned based on total points (mild ≤3, moderate 4 to 6, and severe ≥7 points). The association between MAC score and device migration/embolization was evaluated.
Of 117 patients in the TMVR in MAC registry, 87 had baseline cardiac CT of adequate quality. Of these, 15 were treated with transatrial access and were not included. The total cohort included 72 (trans-septal = 37, transapical = 35). Mean patient age was 74 ± 12 years, 66.7% were female, and the mean Society of Thoracic Surgery risk score was 15.4 ± 10.5%. The mean MAC score was 7.7 ± 1.4. Embolization/migration rates were lower in higher scores: Patients with a MAC score of 7 had valve embolization/migration rate of 12.5%, MAC score ≥8 had a rate of 8.7%, and a MAC score of ≥9 had zero (p = 0.023). Patients with a MAC score of ≤6 had 60% embolization/migration rate versus 9.7% in patients with a MAC score ≥7 (p < 0.001). In multivariable analysis, a MAC score ≤6 was in independent predictor of valve embolization/migration (odds ratio [OR]: 5.86 [95% CI: 1.00 to 34.26]; p = 0.049).
This cardiac CT-based score provides a systematic method to grade MAC severity which may assist in predicting valve embolization/migration during trans-septal or transapical ViMAC procedures.
本研究旨在建立一种基于计算机断层扫描（CT）的二尖瓣环钙化（MAC）严重程度评分系统，有望帮助预测经导管二尖瓣（MV）置换术（TAVR）中使用球囊扩张主动脉经导管心脏瓣膜时瓣膜栓塞的风险。
TAVR 作为一种替代治疗方法，正在为不适合手术的严重 MAC 患者提供新的选择。虽然心脏 CT 是评估 ViMAC 候选者的首选成像方式，但尚未建立用于量化 MAC 严重程度的标准化分级系统。
我们对接受 ViMAC 的患者进行了多中心回顾性心脏 CT 和临床结局研究。使用以下特征创建了基于 CT 的 MAC 评分：平均钙厚度（mm）、环形周长受累程度、一个或两个纤维三角的钙化以及一个或两个瓣叶的钙化。根据严重程度（总最高分=10 分）为特征赋值，并根据总分（轻度评分≤3 分，中度评分 4-6 分，重度评分≥7 分）确定严重程度等级。评估 MAC 评分与设备迁移/栓塞之间的关联。
在 MAC 注册中心的 117 名 TAVR 患者中，87 名患者具有足够质量的基线心脏 CT。其中，15 名经心房入路治疗，未纳入本研究。总队列包括 72 名患者（经房间隔=37 名，经心尖=35 名）。患者平均年龄为 74±12 岁，66.7%为女性，平均胸外科协会风险评分 15.4±10.5%。平均 MAC 评分为 7.7±1.4。分数较高的患者发生栓塞/迁移的比率较低：MAC 评分为 7 的患者瓣膜栓塞/迁移率为 12.5%，MAC 评分≥8 的患者为 8.7%，MAC 评分≥9 的患者为 0（p=0.023）。MAC 评分为≤6 的患者栓塞/迁移率为 60%，而 MAC 评分≥7 的患者为 9.7%（p<0.001）。多变量分析显示，MAC 评分为≤6 是瓣膜栓塞/迁移的独立预测因子（比值比[OR]：5.86[95%可信区间：1.00 至 34.26]；p=0.049）。
该基于心脏 CT 的评分系统提供了一种系统的方法来分级 MAC 严重程度，这可能有助于预测经房间隔或经心尖 ViMAC 手术期间瓣膜栓塞/迁移的风险。
