Objective: To investigate the cardiovascular magnetic resonance (CMR) imaging characteristics and influence factors of aortic insufficiency (AI) patients with myocardial fibrosis. Method: This retrospective study included 59 AI patients who received CMR and transthoracic echocardiography (TTE) examinations from June 2011 to February 2015. AI patients were divided into 2 groups: bicuspid aortic valve (BAV) group (n=30) and non-BAV group (n=29). Patients were also divided into late gadolinium enhancement (LGE) group (n=27) and non-LGE group (n=32). The baseline clinical characteristics were collected through electronic medical records. Hemodynamic parameters such as grade of AI, cardiac functional parameters and LGE mass fraction (LGE%) were measured by CMR post-processing analysis. Kappa test was used to assess the consistency of AI severity between CMR and TTE, and the multivariate logistic regression analysis was performed to evaluate influence factors of myocardial fibrosis in AI patients. Results: (1) 56 (94.9%) patients were male, and the mean age was (44.2±11.0) years old. There was no significant difference in age and gender, hypertension, hyperlipidemia, alcoholic consumption between BAV and non-BAV group (all P>0.05). There were a higher proportion of smoking history (P=0.008), a lower body mass index (BMI) (P=0.020) in the LGE group than in the non-LGE group. (2) The accuracy of CMR in diagnosis of BAV was 96.7% (29/30) compared to the gold standard. In the BAV group, 20 patients (66.7%) were with fusion of left and right cusp (L-R), 5 patients (16.7%) were with fusion of right and noncoronary cusp (R-N), 5 patients (16.7%) were with fusion of left and noncoronary cusp (L-N); patients with BAV had larger left ventricular end diastolic volume index (LVEDVi), left ventricular end systolic volume index (LVESVi), higher proportion of LGE and lower left ventricular ejection fraction (LVEF) than those in non-BAV group (all P<0.05). There were 19 patients with BAV in the LGE group, the cases of L-R, R-N, L-N were 10 (52.6%), 5 (26.3%), and 4 (21.1%), respectively. In the non-LGE group, patients with BAV of L-R, R-N, L-N were 10 (90.9%), 0, and 1 (9.1%), respectively. Patients with LGE had lower body surface area (BSA), LVEF and larger LVEDVi, LVESVi, left ventricular mass index (LVMi) and higher proportion of BAV compared patients without LGE. In addition, the proportion of moderate and severe AI patients was significantly higher in BAV group than in non-BAV group (P=0.009). (3) The consistency of CMR and TTE in evaluating the severity of AI patients: the agreement between TTE and CMR regarding AI severity was satisfactory (kappa value was 0.624, 95%CI 0.402-0.831, P<0.001). (4) The linear regression analysis demonstrated a negative correlation between LVEF and LGE% in BAV and non-BAV group (P<0.001). The multivariate logistic regression analysis showed that the presence of BAV was an independent risk factor of left ventricucar fibrosis (OR=5.050, 95%CI 1.220-20.908, P=0.025) after adjustment for LVEF, hypertension, LVEDVi and LVMi. Conclusion: Multi-parametric CMR provides a satisfactory noninvasive tool for estimation of myocardial fibrosis and ventricular remodeling in patients with AI, and BAV is an independent risk factor for myocardial fibrosis in patients with AI.
目的： 探讨主动脉瓣关闭不全（AI）患者心肌纤维化的磁共振成像（CMR）特征，并分析AI患者发生心肌纤维化的影响因素。 方法： 回顾性分析2011年6月至2015年2月在阜外医院经影像资料确诊为慢性AI患者59例，入选者均接受了心脏磁共振（CMR）和经胸超声心动图检查（TTE）。根据是否合并主动脉二瓣化畸形（BAV）将入选者分为BAV组（n=30）和非BAV组（n=29），以病理或食管超声心动图（TEE）为金标准判断患者是否合并BAV；根据是否出现钆对比剂延迟强化（LGE）将入选者分为强化组（n=27）和非强化组（n=32）。通过临床门诊及住院电子资料收集入选者的一般临床资料。CMR图像经后处理分析，计算左心室常规心功能参数、反流严重程度分级等血流动力学参数及LGE质量分数（LGE%）。采用Kappa检验评估TTE和CMR检测AI反流程度的一致性；多因素logistic回归分析评估AI患者发生心肌纤维化的影响因素。 结果： （1）入选者的一般临床资料：研究共纳入AI患者59例，年龄（44.2±11.0）岁，其中男性56例（94.9%）。BAV组与非BAV组患者的年龄、性别构成差异均无统计学意义（P均>0.05），心血管疾病危险因素如高血压、高脂血症及饮酒史等占比差异均无统计学意义（P均>0.05），具有可比性。强化组患者有吸烟史者占比较非强化组高（P=0.008），体重指数较非强化组低（P=0.020），其他项目两组间差异均无统计学意义（P均>0.05）。（2）按不同标准分组患者CMR检测的左心功能及血流动力学参数：与金标准对比CMR诊断BAV的准确率为96.7%（29/30）。BAV组30例患者中左冠窦和右冠窦融合型（L-R型）20例（66.7%）、右冠窦和无冠窦融合型（R-N型）5例（16.7%）、左冠窦和无冠窦融合型（L-N型）5例（16.7%），BAV组患者左心室射血分数（LVEF）低于非BAV组，而左心室舒张末期容积指数（LVEDVi）、左心室收缩末期容积指数（LVESVi）和LGE比例均高于非BAV组（P均<0.05）。强化组患者合并BAV共19例，其中L-R型10例（52.6%）、R-N型5例（26.3%）、L-N型4例（21.1%）；非强化组患者合并BAV共11例，其中L-R型10例（90.9%）、R-N型0例、L-N型1例（9.1%），强化组患者LVEF和体表面积（BSA）均低于非强化组，而LVEDVi、LVESVi和左心室质量指数（LVMi）均高于非强化组，合并BAV的比例高于非强化组（P均<0.05）。BAV组患者中AI反流程度Ⅱ级及以上者占比明显高于非BAV组（P=0.009）。（3）CMR与TTE评估AI严重程度的一致性：CMR与TTE对AI严重程度分级评价的符合率为81.4%（48/59），Kappa值为0.624（95%CI 0.402~0.831，P<0.001）提示二者一致性较好。（4）线性与多因素logistic回归分析结果：线性回归分析结果显示BAV组和非BAV组患者的LVEF均与LGE%呈线性负相关（P均<0.001）。多因素logistic回归分析结果显示，在调整了年龄、LVEF、高血压、LVEDVi和LVMi等因素后，合并BAV仍是AI患者发生心肌纤维化的影响因素（OR=5.050，95%CI 1.220~20.908，P=0.025）。 结论： AI心肌纤维化患者CMR检测的左心功能和血流动力学参数均有明显改变，而合并BAV是AI患者发生心肌纤维化的影响因素。.
Keywords: Aortic valve insufficiency; Magnetic resonance; Myocardial fibrosis.