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Xu D, McBride E, Kalra K, Wong K, Guyton RA, Sarin EL, Padala M. Undersizing mitral annuloplasty alters left ventricular mechanics in a swine model of ischemic mitral regurgitation. J Thorac Cardiovasc Surg 2022; 164:850-861.e8. [PMID: 33288234 PMCID: PMC8099928 DOI: 10.1016/j.jtcvs.2020.09.141] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/23/2020] [Accepted: 09/28/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Undersizing mitral annuloplasty (UMA) is a frequently used surgical repair technique to correct ischemic mitral regurgitation in patients with heart failure. In this study, we sought to test the hypothesis that downsizing the mitral annulus can adversely affect the shape and mechanics of the left ventricle inhibiting its functional recovery. METHODS Eighteen farm swine that underwent an inferolateral myocardial infarction and developed ischemic mitral regurgitation of >2+ severity after 2 months were assigned as follows: 9 swine received an undersized mitral annuloplasty, 6 received papillary muscle approximation (PMA), and 3 animals did not receive any other intervention. Animals lived another 3 months and cardiac magnetic resonance imaging was performed before termination to assess ventricle mechanics and function. RESULTS Ejection fraction was comparable between the 2 repair groups before surgery, but was significantly lower in UMA at 38.89% ± 7.91% versus 50.83% ± 9.04% in the PMA group (P = .0397). Animals receiving UMA had lower regional peak fractional shortening and reduced systolic and diastolic radial velocities compared with PMA and in some regions were lower than sham. Animals that underwent UMA had higher circumferential strain than sham, but lower than PMA. UMA animals have lower longitudinal strain compared to sham group and lower LV torsion than PMA. CONCLUSIONS Undersizing the mitral annulus with an annuloplasty ring can restore valvular competence, but unphysiologically impair ventricle mechanics. Mitral valve repair strategies should focus not only on restoring valve competence, but preserving ventricle mechanics.
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Affiliation(s)
- Dongyang Xu
- Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga
| | - Erin McBride
- Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga
| | - Kanika Kalra
- Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga
| | - Keawepono Wong
- Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga
| | - Robert A Guyton
- Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga; Division of Cardiothoracic Surgery, Department of Surgery, Emory University, Atlanta, Ga
| | - Eric L Sarin
- Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga; Department of Cardiothoracic Surgery, Inova Heart and Vascular Institute, Fairfax, Va
| | - Muralidhar Padala
- Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga; Division of Cardiothoracic Surgery, Department of Surgery, Emory University, Atlanta, Ga.
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Padala M. Invited Commentary. Ann Thorac Surg 2017; 103:827. [PMID: 28219548 DOI: 10.1016/j.athoracsur.2016.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 08/01/2016] [Accepted: 08/11/2016] [Indexed: 11/17/2022]
Affiliation(s)
- Muralidhar Padala
- Structural Heart Research & Innovation Lab, Carlyle Fraser Heart Center at Emory University, 380-B Northyards Blvd, Atlanta, GA 30313.
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Reyhan M, Wang Z, Li M, Kim HJ, Gupta H, Lloyd SG, Dell'Italia LJ, Denney T, Ennis DB. Left ventricular twist and shear in patients with primary mitral regurgitation. J Magn Reson Imaging 2014; 42:400-6. [PMID: 25408263 DOI: 10.1002/jmri.24811] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/30/2014] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To evaluate the relationship between left ventricular (LV) twist, shear, and twist-per-volume and the severity of mitral regurgitation (MR). Primary MR is a valvular disorder that induces LV dysfunction. There exist several measures of LV rotational mechanics, but it remains unclear which measure of LV dysfunction best accords with the severity of MR. We hypothesized that LV systolic twist-per-volume slope would decrease with increasing severity of MR because of both decreases in rotational mechanics and increases in stroke volumes. MATERIALS AND METHODS Normal subjects (n = 54), moderate MR patients (n = 29), and severe MR patients (n = 54) were studied. Magnetic resonance imaging (MRI) was performed on a 1.5T scanner and grid-tagged LV images were collected at the LV base and LV apex. Measures of LV rotational mechanics were derived from tagged images using Fourier Analysis of STimulated echoes (FAST). RESULTS Peak systolic twist-per-volume slope was significantly different for all pairwise comparisons (P < 0.0001) and compared to normal subjects (-0.14 ± 0.05°/mL) was decreased in moderate MR (-0.12 ± 0.04°/mL) and further decreased in severe MR (-0.07 ± 0.03°/mL). CONCLUSION Peak systolic twist-per-volume slope significantly decreased with increasing severity of MR and is therefore a suitable quantitative imaging biomarker for LV dysfunction in patients with MR.
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Affiliation(s)
- Meral Reyhan
- Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.,Department of Bioengineering, University of California, Los Angeles, California, USA
| | - Zhe Wang
- Department of Bioengineering, University of California, Los Angeles, California, USA.,Department of Radiological Sciences, University of California, Los Angeles, California, USA
| | - Ming Li
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
| | - Hyun J Kim
- Department of Radiological Sciences, University of California, Los Angeles, California, USA
| | - Himanshu Gupta
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Birmingham VA Medical Center, Birmingham, Alabama, USA
| | - Steven G Lloyd
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Birmingham VA Medical Center, Birmingham, Alabama, USA
| | - Louis J Dell'Italia
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Birmingham VA Medical Center, Birmingham, Alabama, USA
| | - Thomas Denney
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
| | - Daniel B Ennis
- Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.,Department of Bioengineering, University of California, Los Angeles, California, USA.,Department of Radiological Sciences, University of California, Los Angeles, California, USA
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Reyhan M, Kim HJ, Brown MS, Ennis DB. Intra- and interscan reproducibility using Fourier Analysis of STimulated Echoes (FAST) for the rapid and robust quantification of left ventricular twist. J Magn Reson Imaging 2013; 39:463-8. [PMID: 23633244 DOI: 10.1002/jmri.24162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 03/12/2013] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To assess the intra- and interscan reproducibility of LV twist using FAST. Assessing the reproducibility of the measurement of new MRI biomarkers is an important part of validation. Fourier Analysis of STimulated Echoes (FAST) is a new MRI tissue tagging method that has recently been shown to compare favorably with conventional estimates of left ventricular (LV) twist from cardiac tagged images, but with significantly reduced user interaction time. MATERIALS AND METHODS Healthy volunteers (N = 10) were scanned twice using FAST over 1 week. On day 1, two measurements of LV twist were collected for intrascan comparisons. Measurements for LV twist were again collected on day 8 for interscan assessment. LV short-axis tagged images were acquired on a 3 Tesla (T) scanner to ensure detectability of tags during early and mid-diastole. Peak LV twist is reported as mean ± SD. Reproducibility was assessed using the concordance correlation coefficient (CCC) and the repeatability coefficient (RC) (95% confidence interval [CI] range). RESULTS Mean peak twist measurements were 13.4 ± 4.3° (day 1, scan 1), 13.6 ± 3.7° (day 1, scan 2), and 13.0 ± 2.7° (day 8). Bland-Altman analysis resulted in intra- and interscan bias and 95% CI of -0.6° [-1.0°, 1.6°] and 1.4° (-1.0°, 3.0°), respectively. The Bland-Altman RC for peak LV twist was 2.6° and 4.0° for intra- and interscan, respectively. The CCC was 0.9 and 0.6 for peak LV twist for intra- and interscan, respectively. CONCLUSION FAST is a semi-automated method that provides a quick and quantitative assessment of LV systolic and diastolic twist that demonstrates high intrascan and moderate interscan reproducibility in preliminary studies.
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Affiliation(s)
- Meral Reyhan
- Biomedical Physics Interdepartmental Program University of California, Los Angeles, California, USA; Department of Radiological Sciences, University of California, Los Angeles, California, USA
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