Monographic Research·Clinical Application of Cardiac MR
Exploring the hemodynamic changes of the ascending aorta before and after interventricular septal myocardial resection in obstructive hypertrophic cardiomyopathy by CMR 4D Flow technology
Luo Xinyi, Lu Guanyu, Ou Jiehao, Yang Yuelong, Cao Liqi, Wu Zhigang, Li Jinglei, Liu Hui
Published 2024-01-20
Cite as J Chin Physician, 2024, 26(1): 25-30. DOI: 10.3760/cma.j.cn431274-20231031-00479
Abstract
ObjectiveTo investigate the hemodynamic changes in the ascending aorta (AAo) before and after interventricular septal myocardial resection in obstructive hypertrophic cardiomyopathy (HOCM) using cardiac magnetic resonance four-dimensional blood flow (CMR 4D Flow) technology.
MethodsHOCM patients who underwent interventricular septal myocardial resection at Guangdong Provincial People′s Hospital from May 2021 to September 2022 were prospectively included. Age and gender matched healthy volunteers (control group) were included during the same period. Both the control group and HOCM patients underwent CMR examination (including cine sequence and 4D Flow sequence) before and 6 months after surgery. CMR 4D flow technology was used to evaluate changes in AAo preoperative and postoperative blood flow patterns (eddy currents, spiral flow), maximum energy loss (ELmax), and average energy loss (ELavg). HOCM patients underwent laboratory tests, including N-terminal pro-brain natriuretic peptide (N-pro BNP) and high-sensitivity troponin T (hsTnT). At the same time, the correlation between postoperative energy loss in HOCM patients and the degree of improvement in laboratory biomarkers was explored.
ResultsA total of 15 HOCM patients and 15 healthy volunteers were included. (1) In terms of blood flow patterns, the preoperative spiral flow degree of HOCM patients was significantly higher than that of the control group (P=0.001), but the postoperative difference was not statistically significant (P=0.059). The degree of eddy currents in HOCM patients before and after surgery was higher than that in the control group (all P<0.05). (2) In terms of energy loss, the preoperative ELmax [21.17(14.30-28.10)mW vs 10.17(7.66-13.07)mW, P<0.001] and ELavg [4.87(3.46-5.77)mW vs 2.27(2.19-2.27)mW, P=0.023] of HOCM patients were higher than those of the control group, but there was no statistically significant difference between the postoperative and control groups (all P>0.05). Compared with preoperative, the postoperative ELmax [12.33(8.70-17.41)mW] and ELavg [3.10(2.25-4.40)mW] of AAo in HOCM patients were significantly reduced (mean P=0.001). (3) Correlation analysis showed that there was a positive correlation (r=0.587, P=0.021) between the ELmax of AAo and the degree of improvement in hsTNT after interventricular septum myocardial resection, but no significant correlation (r=0.229, P=0.413) with the degree of improvement in NT-pro BNP.
ConclusionsThe degree of postoperative AAo blood flow disorder in HOCM patients is reduced, and ELmax and ELavg are significantly reduced. The ELmax of postoperative AAo is positively correlated with the degree of improvement in hsTNT, suggesting that ELmax may be applicable for prognostic evaluation of patients.
Key words:
Cardiac imaging techniques; Magnetic resonance imaging; Cardiomyopathy, hypertrophic; Septal myectomy; Ascending aorta
Contributor Information
Luo Xinyi
School of Medicine, South China University of Technology, Guangzhou 510006, China
Department of Radiology, Guangdong Provincial People′s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
Lu Guanyu
Department of Radiology, Guangdong Provincial People′s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
Ou Jiehao
Department of Radiology, Guangdong Provincial People′s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
Yang Yuelong
Department of Radiology, Guangdong Provincial People′s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
Cao Liqi
Department of Radiology, Guangdong Provincial People′s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
Wu Zhigang
Philips Healthcare China, Shenzhen 518000, China
Li Jinglei
Department of Radiology, Guangdong Provincial People′s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
Liu Hui
School of Medicine, South China University of Technology, Guangzhou 510006, China
Department of Radiology, Guangdong Provincial People′s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
