Patients with Asymptomatic Severe Mitral Regurgitation Already Have Significantly Abnormal Left Ventricular Myocardial Ultrastructural Characteristics
Presented During:
Monday, May 4, 2026: 9:00AM - 4:00PM
McCormick Place Lakeside Center
Posted Room Name:
Exhibit Hall, Poster Area
Abstract No:
P0148
Submission Type:
Abstract Submission
Authors:
Yuanjia Zhu (1), Avi Gupta (1), Seung Hyun Lee (1), Catherine Wu (1), Jinsuh Jung (1), Akshay Venkatesh (1), Sidarth Ethiraj (1), Charles Stark (1), Chris Huynh (1), Shin Yajima (2), Y. Joseph Woo (1)
Institutions:
(1) Stanford University, Stanford, CA, (2) Osaka University Graduate of Medicine, Ikeda, NA
Submitting Author:
Yuanjia Zhu
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Stanford University
Stanford University
Co-Author(s):
Avi Gupta
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Stanford University
Stanford University
Lisa Lee
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Stanford University
Stanford University
Catherine Wu
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Stanford University
Stanford University
Jinsuh Jung
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Stanford University
Stanford University
Akshay Venkatesh
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Stanford University
Stanford University
Sidarth Ethiraj
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Stanford University
Stanford University
Charles Stark
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Stanford University
Stanford University
Chris Huynh
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Stanford University
Stanford University
Shin Yajima
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Osaka University Graduate of Medicine
Osaka University Graduate of Medicine
*Joseph Woo
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Stanford University
Stanford University
Presenting Author:
Yuanjia Zhu
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Stanford University
Stanford University
Abstract:
Objective
Mitral valve (MV) surgery remains a class I recommendation for patients with symptomatic severe primary mitral regurgitation (MR). For asymptomatic patients with severe primary MR and preserved left ventricular (LV) function, surgical treatment is currently a class II recommendation. However, the ultrastructural changes in the left ventricular myocardium of these asymptomatic patients remain unclear.
Methods
Thirteen patients with severe MR were enrolled in this study, eight of whom were symptomatic, and five asymptomatic. Three donor hearts were used as controls. LV biopsies were obtained and processed for transmission electron microscopy (TEM). TEM images were acquired at 10,000x and 20,000x magnification. Quantitative analysis was performed using the ImageJ software. Statistical comparisons were made using analysis of variance with post-hoc correction. Statistical significance was defined as p<0.05. This study was approved by the Institutional Review Board.
Results
Qualitatively, myofibrillar disarray, as well as Z-line thickening and disruption, was observed in patients with severe MR, regardless of symptoms, compared with controls. Quantitatively, the sarcomere length was greater in controls (1.63±0.26µm) compared with symptomatic (1.31±0.34µm, p=0.001) and asymptomatic patients (1.38±0.22µm, p=0.001). The mitochondria area was also larger in controls (0.34±0.21µm2) than in symptomatic patients (0.27±0.16µm2, p=0.01). The mitochondria cristae thickness was greater in controls (0.05±0.01µm) compared with symptomatic (0.02±0.003µm, p=0.001) and asymptomatic patients (0.02±0.005µm, p=0.001). Similarly, the mitochondrial major-to-minor axis ratio was higher in controls (1.86±0.97) than in symptomatic (1.63±0.51, p=0.01) and asymptomatic patients (1.54±0.56, p=0.001).
Conclusions
In patients with severe asymptomatic MR, ultrastructural changes in the LV myocardium have already occurred to a degree similar to those observed in patients with severe symptomatic MR. Early surgical intervention in asymptomatic patients with severe MR may be prudent to prevent further adverse remodeling.
Mitral valve (MV) surgery remains a class I recommendation for patients with symptomatic severe primary mitral regurgitation (MR). For asymptomatic patients with severe primary MR and preserved left ventricular (LV) function, surgical treatment is currently a class II recommendation. However, the ultrastructural changes in the left ventricular myocardium of these asymptomatic patients remain unclear.
Methods
Thirteen patients with severe MR were enrolled in this study, eight of whom were symptomatic, and five asymptomatic. Three donor hearts were used as controls. LV biopsies were obtained and processed for transmission electron microscopy (TEM). TEM images were acquired at 10,000x and 20,000x magnification. Quantitative analysis was performed using the ImageJ software. Statistical comparisons were made using analysis of variance with post-hoc correction. Statistical significance was defined as p<0.05. This study was approved by the Institutional Review Board.
Results
Qualitatively, myofibrillar disarray, as well as Z-line thickening and disruption, was observed in patients with severe MR, regardless of symptoms, compared with controls. Quantitatively, the sarcomere length was greater in controls (1.63±0.26µm) compared with symptomatic (1.31±0.34µm, p=0.001) and asymptomatic patients (1.38±0.22µm, p=0.001). The mitochondria area was also larger in controls (0.34±0.21µm2) than in symptomatic patients (0.27±0.16µm2, p=0.01). The mitochondria cristae thickness was greater in controls (0.05±0.01µm) compared with symptomatic (0.02±0.003µm, p=0.001) and asymptomatic patients (0.02±0.005µm, p=0.001). Similarly, the mitochondrial major-to-minor axis ratio was higher in controls (1.86±0.97) than in symptomatic (1.63±0.51, p=0.01) and asymptomatic patients (1.54±0.56, p=0.001).
Conclusions
In patients with severe asymptomatic MR, ultrastructural changes in the LV myocardium have already occurred to a degree similar to those observed in patients with severe symptomatic MR. Early surgical intervention in asymptomatic patients with severe MR may be prudent to prevent further adverse remodeling.
ADULT CARDIAC:
Mitral and Tricuspid Valve
Image or Table
