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JTCVS Open Mar 2021The exact geometric pathogenesis of leaflet tethering in ischemic mitral regurgitation (IMR) and the relative contribution of each component of the mitral valve complex...
BACKGROUND
The exact geometric pathogenesis of leaflet tethering in ischemic mitral regurgitation (IMR) and the relative contribution of each component of the mitral valve complex (MVC) remain largely unknown. In this study, we sought to further elucidate mitral valve (MV) leaflet remodeling and papillary muscle dynamics in an ovine model of IMR with magnetic resonance imaging (MRI) and 3-dimensional echocardiography (3DE).
METHODS
Multimodal imaging combining 3DE and MRI was used to analyze the MVC at baseline, 30 minutes post-myocardial infarction (MI), and 12 weeks post-MI in ovine IMR models. Advanced 3D imaging software was used to trace the MVC from each modality, and the tracings were verified against resected specimens.
RESULTS
3DE MV remodeling was regionally heterogenous and observed primarily in the anterior leaflet, with significant increases in surface area, especially in A2 and A3. The posterior leaflet was significantly shortened in P2 and P3. Mean posteromedial papillary muscle (PMPM) volume was decreased from 1.9 ± 0.2 cm at baseline to 0.9 ± 0.3 cm at 12 weeks post-MI ( < .05). At 12 weeks post-MI, the PMPM was predominately displaced horizontally and outward along the intercommissural axis with minor apical displacement. The subvalvular contribution to tethering is a combination of unilateral movement, outward displacement, and degeneration of the PMPM. These findings have led to a proposed new framework for characterizing PMPM dynamics in IMR.
CONCLUSIONS
This study provides new insights into the complex interrelated and regionally heterogenous valvular and subvalvular mechanisms involved in the geometric pathogenesis of IMR tethering.
PubMed: 36003177
DOI: 10.1016/j.xjon.2020.10.007 -
European Journal of Cardio-thoracic... Jan 2022Papillary muscle rupture (PMR) is a rare but potentially fatal complication of acute myocardial infarction. The aim of this study was to analyse the patient...
OBJECTIVES
Papillary muscle rupture (PMR) is a rare but potentially fatal complication of acute myocardial infarction. The aim of this study was to analyse the patient characteristics and early outcomes of the surgical management of post-infarction PMR from an international multicentre registry.
METHODS
Patients underwent surgery for post-infarction PMR between 2001 through 2019 were retrieved from database of the CAUTION study. The primary end point was in-hospital mortality.
RESULTS
A total of 214 patients were included with a mean age of 66.9 (standard deviation: 10.5) years. The posteromedial papillary muscle was the most frequent rupture location (71.9%); the rupture was complete in 67.3% of patients. Mitral valve replacement was performed in 82.7% of cases. One hundred twenty-two patients (57%) had concomitant coronary artery bypass grafting. In-hospital mortality was 24.8%. Temporal trends revealed no apparent improvement in in-hospital mortality during the study period. Multivariable analysis showed that preoperative chronic kidney disfunction [odds ratio (OR): 2.62, 95% confidence interval (CI): 1.07-6.45, P = 0.036], cardiac arrest (OR: 3.99, 95% CI: 1.02-15.61, P = 0.046) and cardiopulmonary bypass duration (OR: 1.01, 95% CI: 1.00-1.02, P = 0.04) were independently associated with an increased risk of in-hospital death, whereas concomitant coronary artery bypass grafting was identified as an independent predictor of early survival (OR: 0.38, 95% CI: 0.16-0.92, P = 0.031).
CONCLUSIONS
Surgical treatment for post-infarction PMR carries a high in-hospital mortality rate, which did not improve during the study period. Because concomitant coronary artery bypass grafting confers a survival benefit, this additional procedure should be performed, whenever possible, in an attempt to improve the outcome.
CLINICAL TRIAL REGISTRATION
clinicaltrials.gov: NCT03848429.
Topics: Aged; Coronary Artery Bypass; Hospital Mortality; Humans; Mitral Valve Insufficiency; Myocardial Infarction; Papillary Muscles
PubMed: 34718501
DOI: 10.1093/ejcts/ezab469 -
Methods in Molecular Biology (Clifton,... 2021Isolated cardiac tissue allows investigators to study mechanisms underlying normal and pathological conditions, which would otherwise be difficult or impossible to...
Isolated cardiac tissue allows investigators to study mechanisms underlying normal and pathological conditions, which would otherwise be difficult or impossible to perform in vivo. In contrast to ventricular muscle strip preparations, papillary muscles can be prepared without severely damaging the muscle tissue. In this preparation, the isolated papillary muscle is fixed in an environmentally controlled organ bath chamber and electrically stimulated. The evoked twitch force is recorded using a pressure transducer, and parameters such as twitch force amplitude and twitch kinetics are analyzed. A variety of experimental protocols can be performed to investigate the calcium- and frequency-dependent contractility as well as dose-response curves of contractile agents, as well as simulation of pathologic conditions such as acute cardiac ischemia. Mouse papillary muscle preparations have long been the mainstay for studying interactions between intracellular calcium regulation and contractile responses under a number of simulated pathophysiological conditions. These studies are often used to complement in vitro studies performed using isolated neonatal rat cardiac myocytes. In this procedure, we describe how neonatal rat papillary muscles can also be prepared for use in contractile studies.
Topics: Animals; Animals, Newborn; Electric Stimulation; Myocardial Contraction; Myocytes, Cardiac; Papillary Muscles; Rats; Surgical Equipment
PubMed: 34331240
DOI: 10.1007/978-1-0716-1480-8_4 -
Journal of Clinical Medicine Feb 2023Papillary muscle (PPM) involvement in myocardial infarction (MI) increases the risk of secondary mitral valve regurgitation or PPM rupture and may be diagnosed using...
Papillary Muscle Involvement during Acute Myocardial Infarction: Detection by Cardiovascular Magnetic Resonance Using T1 Mapping Technique and Papillary Longitudinal Strain.
Papillary muscle (PPM) involvement in myocardial infarction (MI) increases the risk of secondary mitral valve regurgitation or PPM rupture and may be diagnosed using late gadolinium enhancement (LGE) imaging. The native T1-mapping (nT1) technique and PPM longitudinal strain (PPM-ls) have been used to identify PPM infarction (iPPM) without the use of the contrast agent. This study aimed to assess the diagnostic performance of nT1 and PPM-ls in the identification of iPPM. Forty-six patients, who performed CMR within 14-30 days after MI, were retrospectively enrolled: sixteen showed signs of iPPM on LGE images. nT1 values were measured within the infarcted area (IA), remote myocardium (RM), blood pool (BP), and anterolateral and posteromedial PPMs and compared using ANOVA. PPM-ls values have been assessed on cineMR images as the percentage of shortening between end-diastolic and end-systolic phases. Higher nT1 values and lower PPM-ls were found in infarcted compared to non-infarcted PPMs (nT1: 1219.3 ± 102.5 ms vs. 1052.2 ± 80.5 ms and 17.6 ± 6.3% vs. 21.6 ± 4.3%; -value < 0.001 for both), with no significant differences between the nT1 of infarcted PPMs and IA and between the non-infarcted PPMs and RM. ROC analysis demonstrated an excellent discriminatory power for nT1 in detecting the iPPM (AUC = 0.874; 95% CI: 0.784-0.963; < 0.001). nT1 and PPM-ls are valid tools in assessing iPPM with the advantage of avoiding contrast media administration.
PubMed: 36836032
DOI: 10.3390/jcm12041497 -
European Journal of Cardio-thoracic... Jun 2022
Topics: Humans; Mitral Valve; Mitral Valve Annuloplasty; Mitral Valve Insufficiency; Papillary Muscles
PubMed: 35678572
DOI: 10.1093/ejcts/ezac339 -
Diagnostics (Basel, Switzerland) Apr 2023(1) Background: With the conventional contour surface method (KfM) for the evaluation of cardiac function parameters, the papillary muscle is considered to be part of...
(1) Background: With the conventional contour surface method (KfM) for the evaluation of cardiac function parameters, the papillary muscle is considered to be part of the left ventricular volume. This systematic error can be avoided with a relatively easy-to-implement pixel-based evaluation method (PbM). The objective of this thesis is to compare the KfM and the PbM with regard to their difference due to papillary muscle volume exclusion. (2) Material and Methods: In the retrospective study, 191 cardiac-MR image data sets (126 male, 65 female; median age 51 years; age distribution 20-75 years) were analysed. The left ventricular function parameters: end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined using classical KfW (syngo.via and cvi42 = gold standard) and PbM. Papillary muscle volume was calculated and segmented automatically via cvi42. The time required for evaluation with the PbM was collected. (3) Results: The size of EDV was 177 mL (69-444.5 mL) [average, [minimum-maximum]], ESV was 87 mL (20-361.4 mL), SV was 88 mL and EF was 50% (13-80%) in the pixel-based evaluation. The corresponding values with cvi42 were EDV 193 mL (89-476 mL), ESV 101 mL (34-411 mL), SV 90 mL and EF 45% (12-73%) and syngo.via: EDV 188 mL (74-447 mL), ESV 99 mL (29-358 mL), SV 89 mL (27-176 mL) and EF 47% (13-84%). The comparison between the PbM and KfM showed a negative difference for end-diastolic volume, a negative difference for end-systolic volume and a positive difference for ejection fraction. No difference was seen in stroke volume. The mean papillary muscle volume was calculated to be 14.2 mL. The evaluation with PbM took an average of 2:02 min. (4) Conclusion: PbM is easy and fast to perform for the determination of left ventricular cardiac function. It provides comparable results to the established disc/contour area method in terms of stroke volume and measures "true" left ventricular cardiac function while omitting the papillary muscles. This results in an average 6% higher ejection fraction, which can have a significant influence on therapy decisions.
PubMed: 37189538
DOI: 10.3390/diagnostics13081437 -
Autopsy & Case Reports May 2020
PubMed: 33344286
DOI: 10.4322/acr.2020.169 -
Circulation Journal : Official Journal... Jul 2022
Topics: Abscess; Heart Rupture, Post-Infarction; Humans; Mitral Valve Insufficiency; Papillary Muscles
PubMed: 35228470
DOI: 10.1253/circj.CJ-22-0038 -
JTCVS Techniques Dec 2021
PubMed: 34977710
DOI: 10.1016/j.xjtc.2021.09.019 -
Journal of Cardiac Surgery Dec 2022Mitral valve regurgitation (MR) is a common valvular disorder occurring in up to 10% of the general population. Mitral valve reconstructive strategies may address any of... (Review)
Review
Mitral valve regurgitation (MR) is a common valvular disorder occurring in up to 10% of the general population. Mitral valve reconstructive strategies may address any of the components, annulus, leaflets, and chords, involved in the valvular competence. The classical repair technique involves the resection of the prolapsing tissue. Chordal replacement was introduced already in the '60, but in the mid '80, some surgeons started to use expanded polytetrafluoroethylene (ePTFE) Gore-Tex sutures. In the last years, artificial chords have been used also using transcatheter approach such as NeoChord DS 1000 (Neochord) and Harpoon TSD-5. The first step is to achieve a good exposure of the papillary muscles that before approaching the implant of the artificial chords. Then, the chords are attached to the papillary muscle, with or without the use of supportive pledgets. The techniques to correctly implant artificial chords are many and might vary considerably from one center to another, but they can be summarized into three big families of suturing techniques: single, running or loop. Regardless of how to anchor to the mitral leaflet, the real challenge that many surgeons have taken on, giving rise to some very creative solutions, has been to establish an adequate length of the chords. It can be established based on anatomically healthy chords, but it is important to bear in mind that surgeons work on the mitral valve when the heart is arrested in diastole, so this length could fail to replicate the required length in the full, beating heart. Hence, some surgeons suggested techniques to overcome this problem. Herein, we aimed to describe the current use of artificial chords in real-world surgery, summarizing all the tips and tricks.
Topics: Humans; Mitral Valve; Chordae Tendineae; Mitral Valve Insufficiency; Cardiac Surgical Procedures; Prostheses and Implants; Polytetrafluoroethylene; Treatment Outcome
PubMed: 36321669
DOI: 10.1111/jocs.17076