Improvement in coronary microvascular dysfunction evaluated by cardiac magnetic resonance in patients with hypertrophic obstructive cardiomyopathy after transapical beating-heart septal myectomy

Yun Zhao; Lu Huang; Chenhe Li; Dazhong Tang; Yi Luo; Chunlin Xiang; Xiaoyue Zhou; Jing Fang; Xiang Wei; Liming Xia

doi:10.3389/fcvm.2023.1233004

Improvement in coronary microvascular dysfunction evaluated by cardiac magnetic resonance in patients with hypertrophic obstructive cardiomyopathy after transapical beating-heart septal myectomy

Front Cardiovasc Med. 2023 Oct 24:10:1233004. doi: 10.3389/fcvm.2023.1233004. eCollection 2023.

Authors

Yun Zhao¹, Lu Huang¹, Chenhe Li², Dazhong Tang¹, Yi Luo¹, Chunlin Xiang¹, Xiaoyue Zhou³, Jing Fang², Xiang Wei², Liming Xia¹

Affiliations

¹ Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
² Department of Cardiovascular Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
³ MR Collaboration, Siemens Healthineers Ltd., Shanghai, China.

Abstract

Background: Coronary microvascular dysfunction (CMD) is a pathophysiological mechanism underlying hypertrophic obstructive cardiomyopathy (HOCM). However, few studies have investigated the potential effect of transapical beating-heart septal myectomy (TA-BSM) on coronary microvascular function. This study aimed to evaluate coronary microvascular function in HOCM after TA-BSM using cardiac magnetic resonance (CMR) and to investigate the determinants of improvement in coronary microvascular dysfunction.

Materials and methods: 28 patients with HOCM who underwent TA-BSM were prospectively enrolled in this study from March 2022 to April 2023. All patients received CMR before and after TA-BSM. CMR-derived parameters were compared, including the maximum wall thickness, native T1 value, T2 value, late gadolinium enhancement (LGE), and perfusion indexes (Slope_max, Time_max, and Sl_max). Univariate and multivariate linear regression identified variables associated with the rate of Slope_max change.

Results: Compared with the preoperative parameters, left ventricular function and myocardial perfusion were significantly improved after TA-BSM (all P < 0.05), although still lower than in healthy controls. In the analysis of the myocardial perfusion parameter rate of change, the rate of Slope_max change was the most significant (P = 0.002) in HOCM. In the multivariable regression analysis, age (adjusted β = 0.551), weight of the resected myocardium (adjusted β = 0.191), maximum wall thickness (adjusted β = -0.406), LGE (adjusted β = 0.260), and Δ left ventricular outflow tract (LVOT) pressure gradient (adjusted β = -0.123) were significantly associated with the rate of Slope_max change in HOCM (P < 0.05 for all).

Conclusion: Coronary microvascular dysfunction in both hypertrophic and non-hypertrophic myocardial segments was improved in patients after TA-BSM. Microcirculatory perfusion evaluated by CMR can be a potential tool to evaluate the improvement of CMD in HOCM.

Keywords: Coronary microvascular dysfunction; cardiac magnetic resonance; myocardial perfusion; obstructive hypertrophic cardiomyopathy; transapical beating-heart septal myectomy.