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

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

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2023.1233004

DOI=10.3389/fcvm.2023.1233004

ISSN=2297-055X

ABSTRACT=<sec><title>Background</title><p>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.</p></sec><sec><title>Materials and methods</title><p>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<sub>max</sub>, Time<sub>max</sub>, and Sl<sub>max</sub>). Univariate and multivariate linear regression identified variables associated with the rate of Slope<sub>max</sub> change.</p></sec><sec><title>Results</title><p>Compared with the preoperative parameters, left ventricular function and myocardial perfusion were significantly improved after TA-BSM (all <italic>P</italic> &lt; 0.05), although still lower than in healthy controls. In the analysis of the myocardial perfusion parameter rate of change, the rate of Slope<sub>max</sub> change was the most significant (<italic>P</italic> = 0.002) in HOCM. In the multivariable regression analysis, age (adjusted <italic>β</italic> = 0.551), weight of the resected myocardium (adjusted <italic>β</italic> = 0.191), maximum wall thickness (adjusted <italic>β</italic> = −0.406), LGE (adjusted <italic>β</italic> = 0.260), and Δ left ventricular outflow tract (LVOT) pressure gradient (adjusted <italic>β</italic> = −0.123) were significantly associated with the rate of Slope<sub>max</sub> change in HOCM (<italic>P</italic> &lt; 0.05 for all).</p></sec><sec><title>Conclusion</title><p>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.</p></sec>