Department of Cardiovascular Medicine Mayo Clinic Rochester MN.
Division of Cardiovascular Medicine Tsuchiura Kyodo General Hospital Ibaraki Japan.
J Am Heart Assoc. 2024 Aug 6;13(15):e035000. doi: 10.1161/JAHA.124.035000. Epub 2024 Jul 31.
Myocardial bridging (MB) is accompanied by the dynamic extravascular compression of epicardial coronary arteries, leading to intracoronary hemodynamic disturbance with abnormal coronary flow profiles. We aimed to evaluate the prognostic implications of resistive reserve ratio (RRR), a composite measure of flow and pressure parameters that represents the vasodilatory capacity of the coronary arteries, in patients with angina with nonobstructive coronary artery disease (ANOCA) and MB, in comparison with coronary flow reserve (CFR).
In this retrospective cohort study, we included patients with ANOCA who underwent coronary reactivity testing, where MB was identified by transient constriction in coronary artery segments between systole and diastole. Abnormal CFR and RRR were defined as <2.5 and <2.62, respectively. Major adverse cardiac events, including cardiovascular death, stroke, myocardial infarction, heart failure, and late revascularization, served as outcomes. Among 1251 patients with ANOCA, 191 (15.3%) had MB. The prevalence of abnormal CFR or RRR was not significantly different between patients with and without MB (=0.144 and =0.398, respectively). Over a median follow-up time of 6.9 years, abnormal RRR predicted major adverse cardiac events in patients with MB (hazard ratio [HR], 4.38 [95% CI, 1.71-11.21]; =0.002) and without MB (HR, 1.91 [95% CI, 1.38-2.64]; <0.001). Abnormal CFR predicted major adverse cardiac events in patients without MB (HR, 2.15 [95% CI, 1.54-3.00]; <0.001), whereas it was not predictive of major adverse cardiac events in patients with MB (HR, 2.29 [95% CI, 0.93-5.65]; =0.073).
In patients with ANOCA and MB, impaired RRR was superior to impaired CFR in distinguishing patients at a higher risk of future adverse events, suggesting that RRR may serve as a risk stratification tool in patients with MB and ANOCA.
心肌桥（MB）伴有心外膜冠状动脉的动态血管外压迫，导致冠状动脉内血流动力学紊乱，出现异常的冠状动脉血流轮廓。我们旨在评估阻力储备比（RRR）的预后意义，RRR 是一种代表冠状动脉血管舒张能力的血流和压力参数的综合指标，与冠状动脉血流储备（CFR）相比，在伴有非阻塞性冠状动脉疾病（ANOCA）和 MB 的心绞痛患者中的作用。
在这项回顾性队列研究中，我们纳入了接受冠状动脉反应性测试的 ANOCA 患者，其中 MB 通过冠状动脉节段在收缩期和舒张期之间的短暂收缩来确定。异常 CFR 和 RRR 的定义分别为 <2.5 和 <2.62。主要不良心脏事件，包括心血管死亡、卒中和心肌梗死、心力衰竭和晚期血运重建，作为结局。在 1251 例 ANOCA 患者中，有 191 例（15.3%）有 MB。伴有和不伴有 MB 的患者 CFR 或 RRR 异常的患病率无显著差异（=0.144 和 =0.398，分别）。在中位随访时间 6.9 年期间，异常 RRR 预测伴有 MB（危险比 [HR]，4.38 [95%置信区间，1.71-11.21]；=0.002）和不伴有 MB（HR，1.91 [95%置信区间，1.38-2.64]；<0.001）患者的主要不良心脏事件。异常 CFR 预测不伴有 MB（HR，2.15 [95%置信区间，1.54-3.00]；<0.001）的主要不良心脏事件，但对伴有 MB（HR，2.29 [95%置信区间，0.93-5.65]；=0.073）患者的主要不良心脏事件不具有预测价值。
在伴有 ANOCA 和 MB 的患者中，RRR 受损比 CFR 受损更能区分未来不良事件风险较高的患者，这表明 RRR 可能成为伴有 MB 和 ANOCA 的患者的风险分层工具。
