P148. Patients with Asymptomatic Severe Mitral Regurgitation Already Have Significantly Abnormal Left Ventricular Myocardial Ultrastructural Characteristics
Presented During: Adult Cardiac Poster Session II
Stanford University
Stanford, CA
United States - Contact Me
Dr. Yuanjia Zhu is a third year cardiothoracic surgery Integrated resident at Stanford University. During residency, she received a PhD degree in BioEngineering at Stanford University focusing on valvular biomechanics, surgical repair optimization, device innovation, and cardiovascular tissue engineering. Prior to coming to the bay area, she studied Biomedical Engineering at Northwestern University and received her MD degree from Cleveland Clinic Lerner College of Medicine.
Monday, May 4, 2026: 9:00 AM - 4:00 PM
McCormick Place Lakeside Center
Room: Exhibit Hall, Poster Area
Description
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.
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
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.
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
Presentation Duration
There is no formal presentation for posters. Your poster will be on display on your assigned day from 9:00AM - 4:00PM
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ADULT CARDIAC
Mitral and Tricuspid Valve