| Objective:Pathological features of hypertrophic cardiomyopathy(HCM)are characterized by cardiomyocyte hypertrophy,myocardial fibrosis,and microvascular abnormalities.Among them,coronary microvascular dysfunction(CMD)is an important indicator of adverse events such as sudden cardiac death(SCD),therefore accurate assessment of CMD is of great significance for the risk stratification,treatment strategies and long-term prognosis for HCM patients.The purpose of this study is to investigate the parameter characteristics and prognostic value of the cardiac magnetic resonance(CMR)intravoxel incoherent motion(IVIM)imaging for non-invasive and quantitative evaluation of CMD in HCM patients.Method:Consecutive HCM patients(n=66)and normal volunteers(n=33)underwent CMR examinations from December 2016 to December 2019 were enrolled,and clinical baseline characteristics as well as main imaging characteristics were recorded.The average follow-up time was 29.09±10.34 months.The combined endpoint events included readmission,ventricular tachycardia or ventricular fibrillation,implantable cardioverter defibrillator discharge and sudden cardiac death.All data were analyzed by SPSS 22.0,the intra-observer consistency of parameters was presented by Bland-Altman graph and ICC test,the differences of clinical baseline characteristics and imaging parameters between groups were checked by t test orχ~2 test,the potential relationship between the IVIM parameters and the LGE degrees was analyzed by Pearson or Spearman’s rank correlation coefficient test,the risk factors of the combined endpoint events were evaluated by the log-rank test,and the Kaplan-Meier survival curve was drawn to confirm the prognostic value of the IVIM parameters.Results:IVIM parameters of each group had good reproducibility(ICC>0.9).The D*value and f value of the HCM group were significantly decreased than the normal group(D*:54.92±10.46μm~2/ms vs 70.35±10.36μm~2/ms,p<0.01;f:12.94±1.13%vs 15.12±1.06%,p<0.01).Compared with the non-obstructive HCM group,the D*value and f value of the obstructive HCM group were also decreased(D*:49.55±10.96μm~2/ms vs 55.45±11.30μm~2/ms,p<0.05;f:11.93±1.78%vs13.18±1.63%,p<0.01).The D*value and f value of the LGE group were significantly lower than the non-LGE group(D*:50.22±10.33μm~2/ms vs 66.64±9.73μm~2/ms,p<0.01;f:12.16±1.62%vs 14.79±1.80%,p<0.01).The D,D*and f value between different degrees of LGE had obvious statistic difference(p<0.01).Correlation analysis showed that D*value and f value were negatively correlated with LGE degree respectively(r=-0.515,p<0.01;r=-0.578,p<0.01),that is,D*value and f value decreased with LGE degree increased gradually.The follow-up results showed that 26 HCM patients(39.40%)had combined endpoint events.The occurrence of adverse cardiac events increased with the D*value and f value decreased(r=-0.447,p<0.01;r=-0.325,p<0.01),and the reduction of D*value had significant correlation of the adverse cardiac events(Log-rankχ~2=11.90,p<0.01),that is,the reduction of D*value was a potential risk factor for poor prognosis in HCM patients.Conclusion:CMR-IVIM imaging can non-invasively and quantitatively assess the myocardial microcirculation disorders in HCM patients.The D*and f parameters can sensitively detect abnormal perfusion status in myocardial segments without delayed enhancement,and the D*value has the potential to provide prognostic information for HCM patients. |
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