Coronary microvascular dysfunction (CMD) is among pathophysiological states of significance in hypertrophic cardiomyopathy (HCM). The index of microcirculatory resistance (IMR) has been recognized as an indicator of CMD and considered of important prognostic value in various conditions. The angiography-derived index of microcirculatory resistance (angio-IMR) is a novel guidewire-free method to assess IMR and proved to have favourable correlation with it. This study was designed to assess prognostic impact of CMD in HCM patients, using angio-IMR as a novel non-invasive assessment tool.

Coronary microvascular dysfunction (CMD) is among pathophysiological states of significance in hypertrophic cardiomyopathy (HCM). The index of microcirculatory resistance (IMR) has been recognized as an indicator of CMD and considered of important prognostic value in various conditions. The angiography-derived index of microcirculatory resistance (angio-IMR) is a novel guidewire-free method to assess IMR and proved to have favourable correlation with it. In this study, patients who met the inclusion criteria were collected from two centers, and the angio-IMR of three coronary arteries was measured to monitor their microcirculation. Then, explore the prognostic value of the angio-IMR of the left anterior descending artery (LAD). At the same time combined with the sum of three coronary arteries' angio-IMR, analysis of its prognostic value. In conclusion, this study was designed to assess prognostic impact of CMD in HCM patients, using angio-IMR as a novel non-invasive assessment tool.

Inclusion Criteria:

1. diagnosed with hypertrophic cardiomyopathy(HCM) based on clinical guidelines
2. have qualified image for analysis of angio-IMR

Exclusion Criteria:

1）referred to hospital due to ST-segment elevation myocardial infarction(STEMI), heart failure and cardiopulmonary arrest; 2) Implantation of any DES or DCB; 3）severe valve dysfunction; 4）history of implantation of implantable cardioverter-defibrillator or pacemaker, septal myectomy or septal myocardial ablation; 5）meet the criteria of implantation of implantable cardioverter-defibrillator or pacemaker, septal myectomy or septal myocardial ablation; 6）impaired life-span expectancy due to cancer or other clinical conditions；

We retrospectively enrolled patients who were diagnosed with hypertrophic cardiomyopathy(HCM) and underwent invasive coronary angiography between 2017 and 2024 at two sites (The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China; Ningbo Medical Center Lihuili Hospital, Ningbo, China) .The diagnosis of HCM was based on current clinical guidelines.