BACKGROUND Patients with aortic valve stenosis have been postulated to have coronary microvascular dysfunction (CMD) contributing to the clinical symptoms and adverse outcomes. The coronary angiography (CAG)-derived index of microcirculatory resistance (caIMR) is proposed as a novel, less invasive and pressure-wire-free index to assess CMD. This study aimed to quantify CMD assessed by caIMR and investigate its prognostic impact in patients with aortic valve stenosis. METHODS This study included 77 moderate or severe aortic valve stenosis patients with no obstructive coronary disease (defined as having no stenosis more than 50% in diameter) who underwent caIMR measurement. CMD was defined by caIMR at least 25. Major adverse cardiovascular events (MACE) were the clinical outcomes during the median 40 months of follow-up. RESULTS The incidence of CMD was 47.7%. Seventeen MACE occurred during the follow-up duration. CMD was associated with an increased risk of MACE (log-rank P < 0.001) and an independent predictor of clinical outcomes [hazard ratio 5.467, 95% confidence interval (CI) 1.393-21.458; P = 0.015]. The receiver-operating characteristic (ROC) curve analysis demonstrated that caIMR could provide a significant predictive value for MACE in aortic valve stenosis patients (AUC 0.785, 95% CI 0.609-0.961, P < 0.001). In addition, the risk of MACE was higher in CMD patients with severe aortic valve stenosis (log-rank P < 0.001) and no aortic valve replacement (log-rank P = 0.003) than in other groups. CONCLUSION Aortic valve stenosis patients demonstrated markedly impaired caIMR. CMD assessed by caIMR increases the risk of MACE and is an independent predictor of adverse outcomes in aortic valve stenosis patients. This finding suggests that using caIMR in the clinical assessment may help identify high-risk groups and stimulate earlier intervention.

中文翻译：

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主动脉瓣狭窄和冠状动脉无阻塞患者冠状动脉微血管功能障碍的预后价值。

背景 主动脉瓣狭窄患者被认为患有冠状动脉微血管功能障碍（CMD），导致临床症状和不良后果。冠状动脉造影 (CAG) 衍生的微循环阻力指数 (caIMR) 被提议作为一种新颖的、微创且无压力线的指数来评估 CMD。本研究旨在量化 caIMR 评估的 CMD 并研究其对主动脉瓣狭窄患者预后的影响。方法 本研究纳入了 77 名没有阻塞性冠状动脉疾病（定义为直径不超过 50% 的狭窄）的中度或重度主动脉瓣狭窄患者，他们接受了 caIMR 测量。CMD 的定义是 caIMR 至少为 25。主要不良心血管事件 (MACE) 是中位 40 个月随访期间的临床结果。结果CMD的发生率为47.7%。随访期间发生了 17 例 MACE。CMD 与 MACE 风险增加相关（对数秩 P < 0.001），并且是临床结果的独立预测因子 [风险比 5.467，95% 置信区间 (CI) 1.393-21.458；P = 0.015]。受试者工作特征（ROC）曲线分析表明，caIMR 可以对主动脉瓣狭窄患者的 MACE 提供显着的预测价值（AUC 0.785，95% CI 0.609-0.961，P < 0.001）。此外，重度主动脉瓣狭窄（对数秩 P < 0.001）和未行主动脉瓣置换术（对数秩 P = 0.003）的 CMD 患者发生 MACE 的风险高于其他组。结论 主动脉瓣狭窄患者的 caIMR 明显受损。通过 caIMR 评估的 CMD 会增加 MACE 的风险，并且是主动脉瓣狭窄患者不良结果的独立预测因子。这一发现表明，在临床评估中使用 caIMR 可能有助于识别高危人群并促进早期干预。