Regional geometric differences between regurgitant and non-regurgitant mitral valves in patients with coronary artery disease

Objective: Demonstrate that regional geometric differences exist between regurgitant and non-regurgitant mitral valves (MV's) in patients with coronary artery disease and due to the heterogenous and regional nature of ischemic remodeling in patients with coronary artery disease (CAD), that the available anatomical reserve and likelihood of developing mitral regurgitation (MR) is variable in non-regurgitant MV's in patients with CAD. Methods: In this retrospective, observational study intraoperative three-dimensional transesophageal echocardiographic data was analyzed in patients undergoing coronary revascularization with MR (IMR group) and without MR (NMR group). Regional geometric differences between both groups were assessed and MV reserve which was defined as the increase in antero-posterior (AP) annular diameter from baseline that would lead to coaptation failure was calculated in three zones of the MV from antero-lateral (zone 1), middle (zone 2), and posteromedial (zone 3). Measurements and Main Results: There were 31 patients in the IMR group and 93 patients in the NMR group. Multiple regional geometric differences existed between both groups. Most significantly patients in the NMR group had significantly larger coaptation length and MV reserve than the IMR group in zones 1 (p-value =.005,.049) and 2 (p-value =.00,.00), comparable between the two groups in zone 3 (p-value =.436,.513). Depletion of the MV reserve was associated with posterior displacement of the coaptation point in zones 2 and 3. Conclusions: There are significant regional geometric differences between regurgitant and non-regurgitant MV's in patients with coronary artery disease. Due to regional variations in available anatomical reserve and the risk of coaptation failure in patients with CAD, absence of MR is not synonymous with normal MV function.</p

Mechanical Discordance between Left Atrium and Left Atrial Appendage

During standard transesophageal echocardiographic examinations in sinus rhythm (SR) patients, the left atrial appendage (LAA) is not routinely assessed with Doppler. Despite having a SR, it is still possible to have irregular activity in the LAA. This situation is even more important for SR patients where assessment of the left atrium is often foregone. We describe a case where we encountered this situation and briefly review how to assess the left atrium and its appendage in such a case scenario

Mitral Valve Coaptation Reserve Index:A Model to Localize Individual Resistance to Mitral Regurgitation Caused by Annular Dilation

Objectives: The objective of this study was to develop a mathematical model for mitral annular dilatation simulation and determine its effects on the individualized mitral valve (MV) coaptation reserve index (CRI). Design: A retrospective analysis of intraoperative transesophageal 3-dimensionalechocardiographic MV datasets was performed. A mathematical model was created to assess the mitral CRI for each leaflet segment (A1-P1, A2-P2, A3-P3). Mitral CRI was defined as the ratio between the coaptation reserve (measured coaptation length along the closure line) and an individualized correction factor. Indexing was chosen to correct for MV sphericity and area of largest valve opening. Mathematical models were created to simulate progressive mitral annular dilatation and to predict the effect on the individual mitral CRI. Setting: At a single-center academic hospital. Participants: Twenty-five patients with normally functioning MVs undergoing cardiac surgery. Interventions: None. Measurements and Main Results: Direct measurement of leaflet coaptation along the closure line showed the lowest amount of coaptation (reserve) near the commissures (A1-P1 0.21 ± 0.05 cm and A3-P3 0.22 ± 0.06 cm), and the highest amount of coaptation (reserve) at region A2 to P2 0.25 ± 0.06 cm. After indexing, the A2-to-P2 region was the area with the lowest CRI in the majority of patients, and also the area with the least resistance to mitral regurgitation (MR) occurrence after simulation of progressive annular dilation. Conclusions: Quantification and indexing of mitral coaptation reserve along the closure line are feasible. Indexing and mathematical simulation of progressive annular dilatation consistently showed that indexed coaptation reserve was lowest in the A2-to-P2 region. These results may explain why this area is prone to lose coaptation and is often affected in MR

Cardiac Angiogenic Imbalance Leads to Peripartum Cardiomyopathy

Peripartum cardiomyopathy (PPCM) is an often fatal disease that affects pregnant women who are near delivery, and it occurs more frequently in women with pre-eclampsia and/or multiple gestation. The aetiology of PPCM, and why it is associated with pre-eclampsia, remain unknown. Here we show that PPCM is associated with a systemic angiogenic imbalance, accentuated by pre-eclampsia. Mice that lack cardiac PGC-$1\alpha$, a powerful regulator of angiogenesis, develop profound PPCM. Importantly, the PPCM is entirely rescued by pro-angiogenic therapies. In humans, the placenta in late gestation secretes VEGF inhibitors like soluble FLT1 (sFLT1), and this is accentuated by multiple gestation and pre-eclampsia. This anti-angiogenic environment is accompanied by subclinical cardiac dysfunction, the extent of which correlates with circulating levels of sFLT1. Exogenous sFLT1 alone caused diastolic dysfunction in wild-type mice, and profound systolic dysfunction in mice lacking cardiac PGC-$1\alpha$. Finally, plasma samples from women with PPCM contained abnormally high levels of sFLT1. These data indicate that PPCM is mainly a vascular disease, caused by excess anti-angiogenic signalling in the peripartum period. The data also explain how late pregnancy poses a threat to cardiac homeostasis, and why pre-eclampsia and multiple gestation are important risk factors for the development of PPCM

A Practical Approach to Echocardiographic Assessment of Perioperative Diastolic Dysfunction

The Doppler assessment of diastolic dysfunction (DD) is not part of a standard comprehensive intraoperative echocardiographic examination. Although the reasons may be many, the lack of a simplified algorithm for the assessment of DD specific to the perioperative arena, the implications of this diagnosis on clinical care, and the absence of therapeutic options are some of the commonly cited reasons. In this article, the authors address these possible reasons for the lack of routine application of Doppler indices to assess perioperative DD. The authors have chosen to highlight some of the most common conceptual questions, which often have been raised by anesthesiologists, and attempted to suggest answers. Drawing from their experience and data, the authors propose a simplified algorithm for the application of Doppler to assess and diagnose DD with an individualized and a mechanistic approach. The proposed algorithm is from within the premise of the published guidelines and attempts to simplify the perioperative approach. The authors hope this approach will be simple enough for routine application to affect therapy and a tangible change in outcome. The authors suggest that knowledge of left atrial size is valuable as a marker for persistently increased left ventricular end-diastolic pressure and its possible role in risk stratification. (C) 2012 Elsevier Inc. All rights reserved