The role of cleft and/or indentation in mitral regurgitation etiology detected by three-dimensional echocardiography in patients with hypertrophic cardiomyopathy
Authors: Yildirim C , Guler A , Tanboga İH , Birant A , Sancar K M , Uygur B , Zencirkiran Agus H , Tukenmez Karakurt S , Turkvatan Cansever A , Erturk M , Babur Guler G 
Published: June 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Aim
The pathophysiology of hypertrophic cardiomyopathy (HCM) consists of dynamic left ventricular outflow tract obstruction, myocardial ischemia, diastolic dysfunction and mitral regurgitation. Mitral regurgitation may be secondary to left ventricular outflow tract obstruction (LVOTO) or related to primary mitral valve pathologies. Three-dimensional (3D) echocardiography has revolutionized imaging of the mitral valve by allowing real-time direct visualization of the mitral valve leaflets in HCM. 3D echocardiography has been using increasingly to evaluate mitral valve clefts and indentations. The aim of this study is to define the frequency of clefts and indentations, and to determine their contribution to mitral regurgitation in patients who are diagnosed HCM and moderate or severe mitral regurgitation by imaging with 3D echocardiography.

Methodology
A total of 74 patients who were diagnosed with HCM in accordance with current guidelines and moderate or severe mitral regurgitation who underwent 3D transesophageal echocardiography (TEE) between Aug 2018 and May 2022 were retrospectively enrolled. In the control group, 200 patients with moderate or severe mitral regurgitation without diagnosis of HCM were selected. Two groups were compared with each other by demographical, echocardiographical features and cardiac magnetic resonance images.

Results
Our final patient population was a total of 50 patients after exclusion criteria. The number of 24 (48%) was female and the number of 26 (52%) was male. There was 89 female patient (44,5%) and 111 male patient (55,5%) in the control group. Patients who are diagnosed HCM were younger compared with the control group (mean age 54,5 ±14 year for HCM patients versus 61±14 year for control patients). Cleft/indentation was present in 14 (28%) HCM patients versus 31 (15,6%) in control patients. It was determined that cleft/indentation was more prevelant in HCM patients (p = 0,041). When we evaluate the direction of mitral regurgitation jet with the presence of celft/indentation, there was a significant association between anteriorly directed mitral regürgitation jet and the presence of cleft (p = 0,003).

Conclusion
In this study, the frequency of cleft/indentations in HCM patients was 28%, it means that cleft/indentation is more often in HCM patients according to the patients who have moderate or severe mitral regurgitation without HCM. When the cleft exists, it affects on the direction of mitral regurgitation and leads to anteriorly directed jet. On the other hand, the indentations have no effect on the direction of mitral regurgitation jet. As a result, 3D mitral valve modeling can be helpful to make a differential diagnosis in HCM patients with anteriorly directed mitral regurgitation jet. Morover, there is no significant efficacy in management of mitral regurgitation by using 3D mitral valve modeling to describe indentations solely.