Contemporary imaging of normal mitral valve anatomy and function

Cardiovascular multimodality imaging in women: a scientific statement of the European Association of Cardiovascular Imaging of the European Society of Cardiology

Cardiovascular diseases (CVD) represent an important cause of mortality and morbidity in women. It is now recognized that there are sex differences regarding the prevalence and the clinical significance of the traditional cardiovascular (CV) risk factors as well as the pathology underlying a range of CVDs. Unfortunately, women have been under-represented in most CVD imaging studies and trials regarding diagnosis, prognosis, and therapeutics. There is therefore a clear need for further investigation of how CVD affects women along their life span. Multimodality CV imaging plays a key role in the diagnosis of CVD in women as well as in prognosis, decision-making, and monitoring of therapeutics and interventions. However, multimodality imaging in women requires specific consideration given the differences in CVD between the sexes. These differences relate to physiological changes that only women experience (e.g. pregnancy and menopause) as well as variation in the underlying pathophysiology of CVD and also differences in the prevalence of certain conditions such as connective tissue disorders, Takotsubo, and spontaneous coronary artery dissection, which are all more common in women. This scientific statement on CV multimodality in women, an initiative of the European Association of Cardiovascular Imaging of the European Society of Cardiology, reviews the role of multimodality CV imaging in the diagnosis, management, and risk stratification of CVD, as well as highlights important gaps in our knowledge that require further investigation.

Degenerative mitral regurgitation

Degenerative mitral regurgitation is a major threat to public health and affects at least 24 million people worldwide, with an estimated 0.88 million disability-adjusted life years and 34,000 deaths in 2019. Improving access to diagnostic testing and to timely curative therapies such as surgical mitral valve repair will improve the outcomes of many individuals. Imaging such as echocardiography and cardiac magnetic resonance allow accurate diagnosis and have provided new insights for a better definition of the most appropriate timing for intervention. Advances in surgical techniques allow minimally invasive treatment with durable results that last for ≥20 years. Transcatheter therapies can provide good results in select patients who are considered high risk for surgery and have a suitable anatomy; the durability of such repairs is up to 5 years. Translational science has provided new knowledge on the pathophysiology of degenerative mitral regurgitation and may pave the road to the development of medical therapies that could be used to halt the progression of the disease.

Surgical Restoration of Antero-Apical Left Ventricular Aneurysms: Cardiac Computed Tomography for Therapy Planning

Background

Surgical ventricular restoration (SVR) leads to functional improvement by volume reduction and restoration of left ventricular (LV) geometry. Our purpose was to refine the planning for SVR using cardiac computed tomography (CCT).

Methods

The possibility to anticipate the postoperative residual LV volume was assessed using CCT in 205 patients undergoing SVR combined with coronary artery bypass grafting (77%), mitral valve repair/replacement (19%) and LV thrombectomy (19%). The potential of CCT to guide the procedure was evaluated. Additionally, the predictive value of CCT characteristics on survival was addressed.

Results

30-day, 1- and 5-year survival was 92.6, 82.7, and 72.1%, respectively, with a marked reduction of NYHA class III-IV quota after surgery (95.1% vs. 20.5% in the follow-up). Both pre- and postoperative LV end-systolic volume index (LVESVI) were predictive of all defined endpoints according to the following tertiles: preoperative: <74 ml/m², 74–114 ml/m² and >114 ml/m²; postoperative: <58 ml/m², 58–82 ml/m² and >82 ml/m². On average, a 50 ml/m² increase of preoperative LVESVI was associated with a 35% higher hazard of death (p = 0.043). Aneurysms limited to seven antero-apical segments (1–7) were associated with a lower death risk (n = 60, HR 0.52, CI 0.28–0.96, p = 0.038). LVESVI predicted by CCT was found to correlate significantly with effectively achieved LVESVI (r = 0.87 and r = 0.88, respectively, p < 0.0001).

Conclusions

CCT-guided SVR can be performed with good mid-term survival and significant improvement in HF severity. CCT-based assessment of achievable postoperative LV volume helps estimate the probability of therapeutic success in individual patients.

Echocardiographic characteristics of non-resectional ring-only valve repair in mitral valve prolapse

BACKGROUND

Simple mitral valve repair (MVR) using a ring-only approach (ROA) was recently proposed for some complex forms of bileaflet myxomatous mitral valve prolapse (MVP). Nevertheless, few data are available concerning the characteristics of MVP patients that may benefit from this simple repair technique.

METHODS

Based on 39 consecutive patients (28 men; mean age 57 ± 15) with severe primary Mitral regurgitation (MR) caused by bileaflet MVP referred for MVR, we sought to identify the preoperative echocardiographic parameters associated with successful ROA repair.

RESULTS

Twenty-three patients (59%) underwent standard resectional MVR (SMVR) while 16 (41%) underwent ROA. Cardiopulmonary bypass and cross clamp times were lower in ROA than in SMVR (74 ± 27 min vs 99 ± 42 min and 49 ± 19 min vs 70 ± 25 min, respectively, p = 0.03 and p = 0.005). ROA patients were more frequently women (50% vs 13%, p = 0.027). Echocardiographic characteristics of successful ROA were mid-late systolic MR, a paradoxical systolic papillary muscle displacement, and paradoxical systolic annulus expansion (PAE). A prolapsing depth <10 mm, the absence of flail leaflet and ruptured chordae, the presence of multiple jets, more often in the central part of the valve were also associated with ROA. Non hemodynamic systolic anterior motion and residual trivial MR tended to be more frequent in ROA than in SMVR.

CONCLUSION

Simple and fast MVR using a ROA is feasible in 4/10 patients with complex forms of bileaflet MVP. Successful ROA patients were more frequently women, with mid-late systolic central multiple jet, low prolapse depth, absence of chordal rupture or flail leaflet and PAE.

Influence of Prolapse Volume in Mitral Valve Prolapse

Mitral valve prolapse (MVP) is characterized by excessive leaflet tissue leading to a wide spectrum of mitral regurgitation (MR) ranging from trivial to severe. The prolapse volume (PV) below the prolapsing leaflets in end-systole was suspected to impact both chamber remodeling and MR grading in MVP. Based on 157 consecutive patients (45 women; mean age 62±15) referred for CMR assessment of MR, either from MVP (n = 91; 58%) or fibroelastic disease (FED) (n = 66; 42%), we sought to study (i) the interaction between PV and cardiac chamber geometry (ii) to study the impact of PV on MR quantification in MVP. Despite similar left ventricular (LV) size, PV was larger in MVP (11±9ml) than in FED (2±2ml). PV progressively increased with the severity of MR in MVP but not in FED. Despite a low regurgitant volume (32±18ml), some MVP patients with less than moderate MR exhibit significant cardiac chambers remodeling compared to 52 age and sex-matched controls. PV correlated significantly (r = 0.52) with the LV dilatation in severe MR but also in less than moderate MR. In MVP, PV>14ml was associated with a significant underestimation (Bias=-26±32ml) of regurgitant volume by PISA compared to CMR. In conclusion, in MVP, PV may play a role in left cardiac chambers remodeling, even in patients without severe MR, and in discordant grading of MR between echocardiography and CMR.

Usefulness of 3-Tesla Cardiac Magnetic Resonance to Detect Mitral Annular Disjunction in Patients With Mitral Valve Prolapse

Mitral annulus disjunction (MAD) is characterized by a separation between the atrial wall mitral junction and the left ventricular (LV) free wall. Little is known regarding cardiac magnetic resonance (CMR) performance to detect MAD and its prevalence in mitral valve prolapse (MVP). Based on 89 MVP patients (63 women; mean age 64 ± 13) referred for CMR assessment of MR, either from myxomatous mitral valve disease (MMVP) (n = 40; 45%) or fibroelastic disease (n = 49; 55%), we sought to assess the frequency of MAD and its consequences on LV morphology. Patients were classified in 2 groups according to MAD presence (MAD+) or absence (MAD-). MAD (measuring 8 ± 4 mm) was diagnosed in 35% (31 of 89) of MVP patients, more frequently in MMVP than fibroelastic disease (60% vs 14%). MAD+ was associated with MMVP; bileaflet MVP and nonsustain ventricular tachycardia but not with the severity of MR. Diagnostic accuracy of transthoracic echocardiography for the detection of MAD was fair (65% sensitivity, 96% specificity) with CMR as reference. MAD+ showed significantly enlarged basal and mid LV diameters and enlarged mitral-annulus diameter. In patients with late gadolinium enhancement, presence of LV fibrosis at level of papillary muscle was more frequent in MAD+. After adjustment on age and MR severity, MMVP, and enlarged end-systolic mitral annulus diameter were independently associated with MAD+. In conclusion, MAD was present in about 1/3 of MVP patients, mostly in MMVP and independent of MR severity. Enlarged mitral-annulus and basal LV diameters, nonsustain ventricular tachycardia and papillary muscle fibrosis were associated with MAD presence.

Preprocedural Computed Tomography Evaluation for Minimally Invasive Mitral Valve Surgery: What the Surgeon Needs to Know

The proven success of endoscopic and videoscopic surgery combined with recent advancements in telemanipulation has made the performance of minimally invasive cardiac surgery a clinical reality during the past decade. A complete understanding of the basic concepts of minimally invasive surgery and the recent advancements in peripheral cardiopulmonary bypass techniques help the cardiac imager to provide a clinically meaningful interpretation for the surgical team. In this article we present an overview of minimally invasive mitral valve surgery and the fundamentals of preprocedural computed tomography angiography imaging and highlight the usefulness of cardiac computed tomography as a supplementary tool to echocardiography.

Transcatheter mitral valve interventions: pathophysiological considerations in choosing reconstruction versus transcatheter valve implantation

Over the last few years, several surgical procedures to treat mitral regurgitation (MR) in high-risk or inoperable patients have inspired percutaneous devices, including valve repair and valve replacement technologies. As the field of transcatheter mitral valve intervention is rapidly developing, the interventional community is wondering whether valve implantation should become the leading percutaneous mitral valve therapy, and whether the introduction of reliable replacement technology will reduce the clinical value of repair approaches. Since clinical experience with transcatheter mitral valve implantation (TMVI) is at a preliminary stage and all the patients treated with this approach so far are really sick candidates with prohibitive risk, it is difficult to define properly which patients could benefit more from TMVI versus transcatheter mitral valve repair (TMVR). The specific aim of this report is to state few important clinical and pathophysiological considerations in order to clarify when and why a repair strategy should be preferred over replacement.

Multislice computed tomography-guided surgical repair of acquired posterior left ventricular aneurysms: demonstration of mitral valve and left ventricular reverse remodelling

OBJECTIVES

Involvement of the mitral valve (MV) apparatus represents a challenge in surgical ventricular repair (SVR) of posterior left ventricular (LV) aneurysms. This study sought to investigate whether multislice computed tomography (MSCT) assessment can be used to optimize the surgical procedure for posterior LV aneurysms.

METHODS

Thirty patients (m : w = 24 : 6, age 38-78, median 66 years; mean New York Heart Association class 2.98) with posterior LV aneurysm were operated upon. MSCT was performed in 24 patients before and after surgery. End-diastolic and end-systolic volumes of LV and aneurysm were indexed to body surface area (LVEDVI/LVESVI, AEDVI/AESVI). The MV apparatus was characterized by coaptation distance (CD), tenting area (TA), MV closure angle (MVCA), MV annulus area (MVAA) and interpapillary muscle distance (IMD).

RESULTS

Thirty-day mortality was 10% and 5-year survival rate was 83%. After surgery, LVEDVI decreased from 151.2 ± 84.1 to 85.7 ± 28.3 ml/m(2) (P = 0.001) and LVESVI from 110.6 ± 88.8 to 50.2 ± 22.9 ml/m(2) (P = 0.001). LV ejection fraction increased from 31.5 ± 15.1 to 43.4 ± 9.9% (P = 0.001). Preoperative MSCT showed significantly higher values of MVAA, CD and TA in patients who needed MV repair or replacement. Postoperative reduction of mitral regurgitation in patients without MV surgery corresponded with significant reduction in intercommissural diameter, anteroposterior diameter, MVAA, TA, CD, MVCA and IMD.

CONCLUSIONS

MSCT represents an excellent diagnostic tool for the assessment of MV and LV geometry. MSCT-guided SVR of submitral LV aneurysms leads to excellent mid-term results. On the basis of the MSCT assessment, we propose an algorithm for surgical planning in posterior LV aneurysms.

Reproducibility of a novel echocardiographic 3D automated software for the assessment of mitral valve anatomy

Background

3D transesophageal echocardiography (TEE) is superior to 2D TEE in quantitative anatomic evaluation of the mitral valve (MV) but it shows limitations regarding automatic quantification. Here, we tested the inter-/intra-observer reproducibility of a novel full-automated software in the evaluation of MV anatomy compared to manual 3D assessment.

Methods

Thirty-six out of 61 screened patients referred to our Cardiac Imaging Unit for TEE were retrospectively included. 3D TEE analysis was performed both manually and with the automated software by two independent operators. Mitral annular area, intercommissural distance, anterior leaflet length and posterior leaflet length were assessed.

Results

A significant correlation between both methods was found for all variables: intercommissural diameter (r = 0.84, p < 0.01), mitral annular area (r = 0.94, p > 0, 01), anterior leaflet length (r = 0.83, p < 0.01) and posterior leaflet length (r = 0.67, p < 0.01). Interobserver variability assessed by the intraclass correlation coefficient was superior for the automatic software: intercommisural distance 0.997 vs. 0.76; mitral annular area 0.957 vs. 0.858; anterior leaflet length 0.963 vs. 0.734 and posterior leaflet length 0.936 vs. 0.838. Intraobserver variability was good for both methods with a better level of agreement with the automatic software.

Conclusions

The novel 3D automated software is reproducible in MV anatomy assessment. The incorporation of this new tool in clinical MV assessment may improve patient selection and outcomes for MV interventions as well as patient diagnosis and prognosis stratification. Yet, high-quality 3D images are indispensable.

New concepts for mitral valve imaging

The high complexity of the mitral valve (MV) anatomy and function is not yet fully understood. Studying especially the dynamic movement and interaction of MV components to describe MV physiology during the cardiac cycle remains a challenge. Imaging is the key to assessing details of MV disease and to studying the lesion and dysfunction of MV according to Carpentier. With the advances of computational geometrical and biomechanical MV models, improved quantification and characterization of the MV has been realized. Geometrical models can be divided into rigid and dynamic models. Both models are based on reconstruction techniques of echocardiographic or computed tomographic data sets. They allow detailed analysis of MV morphology and dynamics throughout the cardiac cycle. Biomechanical models aim to simulate the biomechanics of MV to allow for examination and analysis of the MV structure with blood flow. Two categories of biomechanical MV models can be distinguished: structural models and fluid-structure interaction (FSI) models. The complex structure and dynamics of MV apparatus throughout the cardiac cycle can be analyzed with different types of computational models. These represent substantial progress in the diagnosis of structural heart disease since MV morphology and dynamics can be studied in unprecedented detail. It is conceivable that MV modeling will contribute significantly to the understanding of the MV.