Pulmonary arterial hypertension (PAH) still remains a life-threatening disorder with poor prognosis. The right ventricle (RV) adapts to the increased afterload by a series of prognostically significant morphological and functional changes, the adaptive nature should also be understood in the context of ventricular interdependence. We hypothesized that left ventricle (LV) underfilling could serve as an important imaging marker for identifying maladaptive changes and predicting clinical outcomes in PAH patients. We prospectively enrolled patients with PAH who underwent both cardiac magnetic resonance and right heart catheterization between October 2013 and December 2020. Patients were categorized into four groups based on their LV and RV mass/volume ratio (M/V). LV M/V was stratified using the normal value (0.7 g/mL for males and 0.6 g/mL for females) to identify patients with LV underfilling (M/V ≥ normal value), while RV M/V was stratified based on the median value. The primary endpoint was all-cause mortality, and the composite endpoints included all-cause mortality and heart failure-related readmissions. A total of 190 PAH patients (53 male, mean age 37 years) were included in this study. Patients with LV underfilling exhibited higher NT-proBNP levels, increased RV mass, larger RV but smaller LV, lower right ventricular ejection fraction, and shorter 6-min walking distance. Patients with LV underfilling had a 2.7-fold higher risk of mortality than those without and LV M/V (hazard ratio [per 0.1 g/mL increase]: 1.271, 95% confidence interval: 1.082–1.494, p = 0.004) was also independent predictors of all-cause mortality. Moreover, patients with low LV M/V had a better prognosis regardless of the level of RV M/V. Thus, LV underfilling is an independent predictor of adverse clinical outcomes in patients with PAH, and it could be an important imaging marker for identifying maladaptive changes in these patients.

中文翻译：

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PAH 左心室充盈不足：适应性向适应不良转变的潜在指标

肺动脉高压（PAH）仍然是一种危及生命的疾病，预后不良。右心室（RV）通过一系列具有预后意义的形态和功能变化来适应后负荷的增加，这种适应性的本质也应该在心室相互依赖性的背景下理解。我们假设左心室 (LV) 充盈不足可以作为识别 PAH 患者适应不良变化和预测临床结果的重要影像学标志物。我们前瞻性地招募了 2013 年 10 月至 2020 年 12 月期间接受心脏磁共振和右心导管检查的 PAH 患者。根据左心室和右心室质量/体积比 (M/V) 将患者分为四组。使用正常值（男性 0.7 g/mL，女性 0.6 g/mL）对 LV M/V 进行分层，以识别 LV 充盈不足的患者（M/V ≥ 正常值），而 RV M/V 根据正常值（男性 0.7 g/mL，女性 0.6 g/mL）进行分层。中值。主要终点是全因死亡率，复合终点包括全因死亡率和心力衰竭相关的再入院。本研究共纳入 190 名 PAH 患者（53 名男性，平均年龄 37 岁）。左心室充盈不足的患者表现出较高的 NT-proBNP 水平、增加的右心室质量、较大的右心室但较小的左心室、较低的右心室射血分数以及较短的 6 分钟步行距离。左心室充盈不足的患者的死亡风险比无左心室充盈不足的患者高 2.7 倍，并且左心室 M/V（风险比[每增加 0.1 g/mL]：1.271，95% 置信区间：1.082–1.494，p  = 0.004）也全因死亡率的独立预测因子。此外，无论 RV M/V 水平如何，LV M/V 较低的患者预后较好。因此，左心室充盈不足是 PAH 患者不良临床结果的独立预测因子，并且可能是识别这些患者适应不良变化的重要影像学标志物。