Department of Cardiovascular Medicine Mayo Clinic Rochester MN.
Department of Cardiovascular Medicine Simone Veil Hospital Cannes France.
J Am Heart Assoc. 2022 May 3;11(9):e024814. doi: 10.1161/JAHA.121.024814. Epub 2022 Apr 26.
Background Emerging data suggest important prognostic value to left atrial (LA) characteristics, but the independent impact of LA function on outcome remains unsubstantiated. Thus, we aimed to define the incremental prognostic value of LA coupling index (LACI), coupling volumetric and mechanical LA characteristics and calculated as the ratio of left atrial volume index to tissue Doppler imaging a', in a large cohort of patients with isolated floppy mitral valve. Methods and Results All consecutive 4792 patients (61±16 years, 48% women) with isolated floppy mitral valve in sinus rhythm diagnosed at Mayo Clinic from 2003 to 2011, comprehensively characterized and with prospectively measured left atrial volume index and tissue Doppler imaging a' in routine practice, were enrolled, and their long-term survival analyzed. Overall, LACI was 5.8±3.7 and was <5 in 2422 versus ≥5 in 2370 patients. LACI was independently higher with older age, more mitral regurgitation (no 3.8±2.3, mild 5.1±3.0, moderate 6.5±3.8, and severe 7.8±4.3), and with diastolic (higher E/e') and systolic (higher end-systolic dimension) left ventricular dysfunction (all ≤0.0001). At diagnosis, higher LACI was associated with more severe presentation (more dyspnea, more severe functional tricuspid regurgitation, and elevated pulmonary artery pressure, all ≤0.0001) independently of age, sex, comorbidity index, ventricular function, and mitral regurgitation severity. During 7.0±3.0 years follow-up, 1146 patients underwent mitral valve surgery (94% repair, 6% replacement), and 880 died, 780 under medical management. In spline curve analysis, LACI ≥5 was identified as the threshold for excess mortality, with much reduced 10-year survival under medical management (60±2% versus 85±1% for LACI <5, <0.0001), even after comprehensive adjustment (adjusted hazard ratio, 1.30 [95% CI, 1.10-1.53] for LACI ≥5; =0.002). Association of LACI ≥5 with higher mortality persisted, stratifying by mitral regurgitation severity of LA enlargement grade (all <0.001) and after propensity-score matching (=0.02). Multiple statistical methods confirmed the significant incremental predictive power of LACI over left atrial volume index (all <0.0001). Conclusions LA functional assessment by LACI in routine practice is achievable in a large number of patients with floppy mitral valve using conventional Doppler echocardiographic measurements. Higher LACI is associated with worse clinical presentation, but irrespective of baseline characteristics, LACI is strongly, independently, and incrementally determinant of outcome, demonstrating the crucial importance of LA functional response to mitral valve disease.
新兴数据表明，左心房（LA）特征具有重要的预后价值，但 LA 功能对预后的独立影响仍未得到证实。因此，我们旨在确定 LA 耦联指数（LACI）、耦联容积和机械 LA 特征的增量预后价值，并将其定义为左心房容积指数与组织多普勒成像 a'的比值，在一大群孤立性二尖瓣脱垂患者中进行定义。
我们纳入了 2003 年至 2011 年在梅奥诊所诊断为孤立性二尖瓣脱垂且窦性节律的所有 4792 例患者（61±16 岁，48%为女性），这些患者接受了全面特征描述，并在常规实践中前瞻性测量了左心房容积指数和组织多普勒成像 a'，并对其长期生存情况进行了分析。
总体而言，LACI 为 5.8±3.7，<5 的患者有 2422 例，≥5 的患者有 2370 例。LACI 与年龄较大、更严重的二尖瓣反流（无 3.8±2.3、轻度 5.1±3.0、中度 6.5±3.8、重度 7.8±4.3）和舒张（更高的 E/e'）和收缩（更高的收缩末期内径）左心室功能障碍（均 ≤0.0001）独立相关。在诊断时，更高的 LACI 与更严重的临床表现（更多呼吸困难、更严重的功能性三尖瓣反流和肺动脉压升高，均 ≤0.0001）相关，而与年龄、性别、合并症指数、心室功能和二尖瓣反流严重程度无关。在 7.0±3.0 年的随访期间，1146 例患者接受了二尖瓣手术（94%为修复，6%为置换），880 例死亡，780 例接受药物治疗。在样条曲线分析中，LACI≥5 被确定为死亡率过高的阈值，即使在全面调整后（LACI≥5 的 10 年生存率调整后危险比为 1.30 [95%CI，1.10-1.53]；=0.002），药物治疗下的 10 年生存率也明显降低（LACI<5 为 60±2%，LACI≥5 为 85±1%，<0.0001）。LACI≥5 与更高死亡率之间的相关性，在 LA 扩大程度分级的二尖瓣反流严重程度分层（均 <0.001）和倾向评分匹配后（=0.02）仍然存在。多种统计方法证实，LACI 比左心房容积指数具有更强的增量预测能力（均 <0.0001）。
在使用常规多普勒超声测量的大量二尖瓣脱垂患者中，可以通过 LACI 进行 LA 功能评估。更高的 LACI 与更差的临床表现相关，但无论基线特征如何，LACI 都是预后的重要且独立的决定因素，这表明 LA 对二尖瓣疾病的功能反应至关重要。
