Association between left ventricular trabecular complexity and sarcomere mutation in patients with hypertrophic cardiomyopathy
S YangAbstract
Background
Prominent myocardial trabeculae and papillary muscles are characteristic features of hypertrophic cardiomyopathy (HCM). Emerging evidence suggests that certain sarcomere gene mutations may be associated with excessive left ventricular (LV) trabeculation. However, the relationship between LV trabecular complexity and specific genotypes in HCM has not been systematically investigated.
Methods
Consecutive HCM patients who underwent cardiac MRI and genetic testing of eight core sarcomere protein–encoding genes between September 2009 and March 2014 were included. Trabecular complexity was quantified by fractal analysis of cine images to calculate the fractal dimension (FD).
Results
A total of 223 HCM patients (46.5±12.8 years old，155 male) were retrospectively enrolled. There are 122 patients with sarcomere mutation and 101 patients without sarcomere mutation. Compared with healthy controls, patients with sarcomere mutation showed a higher mean apical FD value (P < 0.05 ). Among all the sarcomere mutation patients, patients with MYH7 positive mutation had the global, middle, apical, and max FD values of the MYBPC3 positive HCM patients, which were all significantly higher (all P < 0.05). Receiver-operating curves showed the predictive ability of mean apical FD for differentiating MYBPC3-positive patients (AUC: 0.705). Multivariate logistic regression analysis revealed that mean Apical-FD is independently correlated with MYBPC3 positivity (OR: 3.447 and 3.342 for the two models, respectively adjusted by Mayo II and Toronto score, all P = 0.001). Mean Apical FD showed incremental value for MYBPC3 positive mutation prediction added to Mayo II and Toronto score (AUC 0.726 vs 0.625, P = 0.03; AUC 0.721 vs 0.624, P = 0.024), respectively.
Conclusions
Mean apical FD was independently associated with MYBPC3 mutation. Mean apical FD showed incremental utility in the diagnosis of MYBPC3 mutation when combined with Mayo II and Toronto scores.Graphical abstractFractal Analysis