Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, CA (T.N., W.F.F.).
Department of Cardiovascular Medicine, Chiba University Graduate School Medicine, Japan (T.N.).
Circ Cardiovasc Interv. 2024 Jun;17(6):e013728. doi: 10.1161/CIRCINTERVENTIONS.123.013728. Epub 2024 May 10.
Microvascular resistance reserve (MRR) has been proposed as a specific metric to quantify coronary microvascular function. The long-term prognostic value of MRR measured in stable patients immediately after percutaneous coronary intervention (PCI) is unknown. This study sought to determine the prognostic value of MRR measured immediately after PCI in patients with stable coronary artery disease.
This study included 502 patients with stable coronary artery disease who underwent elective PCI and coronary physiological measurements, including pressure and flow estimation using a bolus thermodilution method after PCI. MRR was calculated as coronary flow reserve divided by fractional flow reserve times the ratio of mean aortic pressure at rest to that at maximal hyperemia induced by hyperemic agents. An abnormal MRR was defined as ≤2.5. Major adverse cardiac events (MACEs) were defined as a composite of all-cause mortality, any myocardial infarction, and target-vessel revascularization.
During a median follow-up of 3.4 years, the cumulative MACE rate was significantly higher in the abnormal MRR group (12.5 versus 8.3 per 100 patient-years; hazard ratio 1.53 [95% CI, 1.10-2.11]; <0.001). A higher all-cause mortality rate primarily drove this difference. On multivariable analysis, a higher MRR value was independently associated with lower MACE and lower mortality. When comparing 4 subgroups according to MRR and the index of microcirculatory resistance, patients with both abnormal MRR and index of microcirculatory resistance (≥25) had the highest MACE rate.
An abnormal MRR measured immediately after PCI in patients with stable coronary artery disease is an independent predictor of MACE, particularly all-cause mortality.
微血管阻力储备（MRR）已被提出作为量化冠状动脉微血管功能的特定指标。在经皮冠状动脉介入治疗（PCI）后稳定的患者中即刻测量的 MRR 的长期预后价值尚不清楚。本研究旨在确定稳定型冠心病患者 PCI 后即刻测量的 MRR 的预后价值。
本研究纳入了 502 例接受选择性 PCI 和冠状动脉生理测量的稳定型冠心病患者，包括 PCI 后使用热稀释法测量压力和流量。MRR 定义为冠状动脉血流储备除以分数血流储备乘以静息时平均主动脉压与最大充血时的比值。异常 MRR 定义为≤2.5。主要不良心脏事件（MACE）定义为全因死亡率、任何心肌梗死和靶血管血运重建的复合终点。
在中位随访 3.4 年期间，异常 MRR 组的累积 MACE 发生率显著较高（12.5 比 8.3 例/100 患者年；风险比 1.53 [95%CI，1.10-2.11]；<0.001）。较高的全因死亡率主要导致了这种差异。多变量分析显示，较高的 MRR 值与较低的 MACE 和死亡率独立相关。根据 MRR 和微血管阻力指数将 4 个亚组进行比较，MRR 和微血管阻力指数均异常（≥25）的患者 MACE 发生率最高。
在稳定型冠心病患者中，PCI 后即刻测量的异常 MRR 是 MACE 的独立预测因素，尤其是全因死亡率。
