Aguiar Rosa Sílvia, Mota Carmo Miguel, Rocha Lopes Luís, Oliveira Eunice, Thomas Boban, Baquero Luis, Cruz Ferreira Rui, Fiarresga António
Department of Cardiology, Hospital de Santa Marta, Lisbon, Portugal; Nova Medical School, Lisbon, Portugal; Heart Center, Hospital da Cruz Vermelha Portuguesa, Lisbon, Portugal.
Nova Medical School, Lisbon, Portugal.
Rev Port Cardiol. 2022 Sep;41(9):761-767. doi: 10.1016/j.repc.2021.07.013. Epub 2022 Jul 20.
Coronary microvascular dysfunction (CMD) is one of the most important pathophysiological features in hypertrophic cardiomyopathy (HCM). The index of microcirculatory resistance (IMR) is an invasive method to assess the coronary microcirculation. The aim was to assess CMD in patients with HCM by IMR.
Adult patients with HCM without epicardial coronary artery disease underwent cardiac catheterization for the assessment of CMD by IMR (normal cut-off value ≤22.0) and coronary flow reserve (CFR) (normal cut-off value ≥2). Cardiovascular magnetic resonance (CMR) was performed to assess the ischemic burden by perfusion imaging during regadenoson-induced hyperemia, and the extent of myocardial fibrosis was assessed by late gadolinium enhancement (LGE), native T1 mapping and extracellular volume (ECV).
Fourteen patients were enrolled with a mean age of 62.8±6.2years, 8 (57.1%) males, of whom 9 (64.3%) had obstructive HCM. Using IMR, CMD was detected in 4 (29%) patients. Among four patients with an IMR>22.0, all had non-obstructive HCM and two had angina. CFR<2 was reported in eight patients (57%). Concordance between IMR and CFR (both normal or both abnormal) was verified in 6 patients (43%). Among four patients with IMR>22.0, perfusion defects were found in two of the three patients who underwent stress CMR. Increased ECV (>28%) was documented in two of the patients with IMR>22 and in three of the patients with IMR≤22.0. LGE was >15% in 2 of the patients with IMR>22 and in 4 with IMR≤22.0.
IMR assessment in HCM is feasible and safe. Patients with abnormal IMR seemed to have more significant tissue abnormalities on CMR.
冠状动脉微血管功能障碍（CMD）是肥厚型心肌病（HCM）最重要的病理生理特征之一。微循环阻力指数（IMR）是评估冠状动脉微循环的一种有创方法。本研究旨在通过IMR评估HCM患者的CMD。
无冠状动脉疾病的成年HCM患者接受心脏导管检查，通过IMR（正常临界值≤22.0）和冠状动脉血流储备（CFR）（正常临界值≥2）评估CMD。采用心血管磁共振成像（CMR），通过瑞加诺生诱发充血期间的灌注成像评估缺血负荷，并通过延迟钆增强（LGE）、固有T1映射和细胞外容积（ECV）评估心肌纤维化程度。
共纳入14例患者，平均年龄62.8±6.2岁，男性8例（57.1%），其中9例（64.3%）为梗阻性HCM。使用IMR检测到4例（29%）患者存在CMD。在IMR>22.0的4例患者中，均为非梗阻性HCM，2例有胸痛症状。8例（57%）患者报告CFR<2。6例（43%）患者IMR和CFR结果一致（均正常或均异常）。在IMR>22.0的4例患者中，3例接受负荷CMR检查的患者中有2例发现灌注缺损。IMR>22的2例患者和IMR≤22.0的3例患者记录到ECV增加（>28%）。IMR>22的2例患者和IMR≤22.0的4例患者LGE>15%。
HCM患者进行IMR评估是可行且安全的。IMR异常的患者在CMR上似乎有更明显的组织异常。
