Echocardiographic predictors of left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve after mitral valve reconstruction for myxomatous valve disease

A balanced mitral leaflet and large ring strategy avoids systolic anterior motion in Barlow's disease

OBJECTIVES

Mitral valve repair for Barlow's disease offers good outcomes but excessive and myxomatous valvular tissue is associated with systolic anterior motion. Although valvular disease might progress after repair and cause long-term systolic anterior motion, few reports focus on this aspect. Herein, we will review our 16-year experience with mitral valve repair for Barlow's disease and systolic anterior motion incidence.

METHODS

We retrospectively reviewed surgical outcomes of 92 cases of mitral valve repair using a balanced leaflet/large ring strategy plus median sternotomy for Barlow's disease (median age 45.1 ± 12.7 years old [19-72], 37 females) from 2004 to 2019. Concomitant surgeries, except for tricuspid valve or anti-arrhythmic surgeries, were excluded.

RESULTS

The follow-up period was 5.8 ± 4.4 years with no deaths. Patients had mitral regurgitation of grade 3/4 (15 cases) or 4/4 (77 cases) due to anterior leaflet (3 cases), posterior leaflet (75 cases), or bileaflet (14 cases) prolapse, with chord elongation (39 cases), chord rupture (22 cases), or a combination of both (14 cases). All cases required ring annuloplasty (median size of 33.0 ± 5.4 mm) combined with leaflet resection (91 cases), chord intervention (12 cases), or indentation closure (2 cases). No case had short- or long-term SAM. The freedom-from-mitral-regurgitation (of greater than grade 2/4) rate was 94.1% over 5 years and 76.0% over 10 years without reoperation.

CONCLUSIONS

Our two-pronged strategy for mitral valve repair in Barlow's disease avoids systolic anterior motion over the long-term, with good outcomes.

Mitral Valve Repair for Mitral Regurgitation in Patients With Marfan Syndrome

BACKGROUND

There is concern about the durability of mitral valve repair (MVr) for mitral regurgitation (MR) in Marfan patients due to limited long-term data. Furthermore, a detailed time course of changes in cardiac function after MVr in Marfan patients has not been reported. We examined repair techniques, postoperative cardiac function, and outcomes of MVr in Marfan patients.

METHODS AND RESULTS

We retrospectively reviewed 29 Marfan patients (mean [±SD] age 27.4±14.8 years) who underwent MVr at The University of Tokyo Hospital from 2010 to 2022. The mean follow-up period was 5.2±3.2 years. The causes of MR were isolated anterior leaflet prolapse in 25% of patients, isolated posterior leaflet prolapse in 11%, and bileaflet prolapse in 64%. Echocardiographic findings showed significant decreases in left ventricular (LV) diastolic and left atrial diameters 1 week after MVr. LV systolic diameter was significantly decreased 3 years after MVr, and LV ejection fraction initially declined before subsequently increasing. The in-hospital and 30-day mortality rates were 0%. At 5 years, the overall survival rate was 94% and the rate of freedom from MR was 84%.

CONCLUSIONS

The mid- to long-term outcomes after MVr in Marfan patients were satisfactory, supporting the durability of MVr in these patients. Postoperative cardiac reverse remodeling occurred in a phased manner in Marfan patients, similar to that in patients with degenerative MR.

Three-dimensional anatomic features of the mitral valve that predict systolic anterior motion occurring during dobutamine stress echocardiography

BACKGROUND/AIM

Left ventricular outflow tract obstruction related to systolic anterior motion (SAM) of the mitral valve is a common complication of dobutamine stress echocardiography (DSE). However, the mechanisms underlying SAM have not been fully characterized. The objective of the present study was to use three-dimensional echocardiography to identify anatomic features of the mitral valve that predispose to SAM during DSE.

METHODS

We retrospectively evaluated consecutive patients included prospectively in our database and who had undergone 3D echocardiography (including an assessment of the mitral valve) before DSE. Patients who had developed SAM during DSE (the SAM+ group) were matched 2:3 with patients who did not (the SAM- group).

RESULTS

One hundred patients were included (mean age: 67 ± 10). Compared with SAM- patients (n = 60), SAM+ patients (n = 40) had a lower mitral annular area, a smaller perimeter, and a smaller diameter (p < .01 for all, except the anteroposterior diameter). The SAM+ group had also a narrower mitral-aortic angle (126 ± 12° vs. 139 ± 11° in the SAM- group; p < .01) and a higher posterior mitral leaflet length (1.4 ± .27 cm vs. 1.25 ± .29, respectively; p < .01). Furthermore, the mitral annulus was more spherical, more flexible, and more dynamic in SAM+ patients than in SAM- patients (p < .05 for all). In a multivariate analysis of anatomic variables, the mitral-aortic angle, the mitral annular area, and posterior leaflet length were independent predictors of SAM (p ≤ .01 for all). In a multivariate analysis of standard echo and hemodynamic variables, the presence of wall motion abnormalities at rest (p < .01) was an independent predictor of SAM.

CONCLUSION

SAM during DSE is multifactorial. In addition to the pharmacologic effects of dobutamine on the myocardium, 3D echocardiographic features of the mitral valve (a smaller mitral annulus, a narrower mitral-aortic angle, and a longer posterior leaflet) appear to predispose to SAM.

Unmasking Severe Systolic Anterior Motion With Left Ventricular Outflow Tract Obstruction Following Mitral Valve Repair

A 38-year-old male with a history of myxomatous mitral valve disease post-repair presented with recurrent dyspnea during exertion. Initial evaluation showed mild systolic anterior motion and mitral regurgitation, but medical management was unsuccessful. The patient underwent reoperation; intraoperative transesophageal echocardiogram with provocation unmasked severe systolic anterior motion and torrential mitral regurgitation.

Preoperative evaluation of systolic murmur with point-of-care echocardiography before an elective thoracic surgery - A case report

BACKGROUND

Systolic murmur suggesting the association of aortic valve (AV) stenosis or obstructive pathology in the left ventricular outflow tract (LVOT) usually requires preoperative echocardiographic evaluation for elective surgery.

CASE

In a 63-year-old female patient undergoing elective thoracic surgery, the systolic murmur was auscultated on the right sternal border of the second intercostal space in the preoperative patient holding area. Point-of-care (POC) transthoracic echocardiography (TTE) demonstrated a systolic jet flow in the LVOT area. The peak systolic velocity of the continuous wave Doppler tracing, aligned to the LVOT and the AV, was approximately 1.5 m/s. The peak/mean pressure gradient was 11/6 mmHg for the AV and 9/5 mmHg for the LVOT. Anesthesia was induced under continuous TTE imaging. Intraoperative transesophageal echocardiography also confirmed the absence of any cardiac pathology.

CONCLUSIONS

POC echocardiography offered a thorough preoperative evaluation of an unexpectedly identified systolic murmur, avoiding a potential delay in the operation schedule for conventional preoperative echocardiographic evaluation.

Echocardiographic Evaluation of Successful Mitral Valve Repair or Need for a Second Pump Run in the Operating Room

Detailed preoperative and intraoperative echocardiographic assessment of the mitral valve apparatus is critical for a successful repair. The recent advent of 3-dimensional transesophageal echocardiography has added an extra pivotal role to transesophageal echocardiography in the assessment of mitral apparatus and mitral regurgitation. Because surgeons must rapidly decide whether cardiopulmonary bypass should be continued to be weaned off or a second pump run should be selected, the echocardiographer conducting intraoperative transesophageal echocardiography is required to be trained according to a certain algorithm. This review summarizes the current clinical role of intraoperative transesophageal echocardiography in mitral valve repair in the operating room.

Midterm Results of Mitral Valve Repair Using Loop Technique With Simple Height Reduction of the Large Posterior Leaflet

OBJECTIVE

Systolic anterior motion (SAM) is one of the most serious problems in mitral valve repair. Height reduction is a key procedure to solve SAM, and there are limited data on the surgical results of height reduction procedure. This study is to assess the effectiveness and midterm results of simple height reduction procedure for SAM in patients with severe mitral regurgitation (MR).

METHODS

From 2008 to 2022, 50 patients underwent loop technique with an additional simple height reduction procedure for prevention of SAM. We examined the midterm results of patients with simple height reduction regarding recurrent MR and reoperation. The follow-up period ranged from 171 to 3,816 days (median, 883 days).

RESULTS

There were 338 patients (87%) who underwent loop technique without height reduction and 50 patients (13%) who underwent loop technique with height reduction. After the height reduction procedure, SAM was prevented in 44 patients, and 6 patients needed volume loading to suppress SAM. Freedom from recurrence of moderate to severe or severe MR at 1, 3, and 5 years was 98%, 88%, and 88% in the height reduction group versus 98%, 96%, and 94% in the group with loop technique alone (P = 0.074). Receiver operating characteristic curves showed that a systolic dimension of 26 mm had a sensitivity of 75% and a specificity of 83% for predicting SAM after height reduction.

CONCLUSIONS

Loop technique with simple height reduction was a simple, secure, and effective procedure to prevent SAM and recurrent significant MR in the midterm periods.

Acute iatrogenic complications after mitral valve repair

BACKGROUND AND AIM OF THE STUDY

Mitral valve repair is the procedure of choice to correct mitral regurgitation. However, some dangerous iatrogenic complications can occur at the end of the procedure. Therefore, we sought to review the most frequent and clinically relevant acute iatrogenic complication following mitral valve repair.

METHODS

A thorough review of the literature has been performed. Criteria for considering studies for this non-systematic review were as follows: observational and interventional studies investigating the acute iatrogenic complications following mitral valve repair, and essential review studies pertinent to the topic.

RESULTS

The most frequent is the systolic anterior motion. Due to a systolic dislocation of the anterior leaflet toward the outflow tract, it causes both obstruction of the outflow tract and mitral regurgitation. Often it is due to excess of catecholamines or to reduced filling of the left ventricle but sometimes needs further surgical maneuvers, focused on moving posteriorly the coaptation line. It can be obtained by shortening the posterior leaflet or increasing the size of the ring or applying an Alfieri stitch to limit the movements of the anterior leaflet. Another complication, often underdiagnosed and potentially lethal, is the injury of the circumflex artery that happens at the level of the anterolateral commissure or P1 zone. Two mechanisms are involved. The first one is the direct injury of the artery by a stitch (roughly 25% of the patients present a distance artery-annulus <3 mm. The second one is the distortion of the artery, attracted toward the annulus by a misplaced stitch. The attraction causes kinking with stenosis of different degrees till functional occlusion. However, the artery has to be far from the annulus and the atrial tissue has to be stiff and resistant, as after an infective process, to move the circumflex artery toward the annulus without tearing. Positioning the stitches very close to the mitral leaflets in the dangerous area is the only prevention to the complication. The treatment in the operating theater is partial or total removal/reimplantation of the annular sutures or coronary artery bypass grafting to the circumflex area. If the injury is demonstrated only after coronary angiography, percutaneous revascularization can be attempted before further surgical treatment.

CONCLUSIONS

Acute iatrogenic complication after mitral repair exists and may compromize patient outcome. Raising awareness about these issues, the precautions to prevent them, and the manners of resolution is therefore mandatory.

A multiparameter algorithm to guide repair of degenerative mitral regurgitation

PURPOSE

Degenerative mitral regurgitation repair using a measured algorithm could increase the precision and reproducibility of repair outcomes.

METHODS

Direct and echocardiographic measurements guide the repair to achieve a coaptation length of 5 to 10 mm and minimize the risk of systolic anterior motion. Leaflet reconstruction restored the normal 2 to 1 ratio of anterior to posterior leaflet length without residual prolapse or restriction. The choice of ring size was based on anterior leaflet length, the distance from the leaflet coaptation point to the septum, and the anterior-posterior ring dimension. Freedom from reoperation and mitral regurgitation recurrence were based on multistate models.

RESULTS

One thousand fifty-one patients had mitral surgery and 1026 (97.6%) were repaired. A2 length was 27.2 ± 4.5 mm; and the reconstructed posterior leaflet was 13.9 ± 2.3 mm. Median ring size was 34 mm and strongly correlated to A2 length (R = 0.76; P < .001). The coaptation length at P2 after repair was 6.4 ± 1.7 mm and 87% of measurements were between 5 and 10 mm. Results at predischarge and 10 years, respectively, included mild regurgitation (7.5% and 26.1%), moderate (0.7% and 15.6%), moderate to severe (0% and 1.4%), and severe (0% and 0%), with mean mitral gradient values 3.5 ± 1.5 and 2.9 ± 1.2 mm Hg, respectively. Systolic anterior motion at discharge and last follow-up were 0.2% and 1.1%, respectively. Ten-year freedom from mitral valve reoperation was 99.7%.

CONCLUSIONS

A simple, reproducible, measured algorithm for degenerative mitral valve repair provides excellent early and late results and is a useful adjunct to established surgical techniques.

Recommendations for Multimodality Cardiovascular Imaging of Patients with Hypertrophic Cardiomyopathy: An Update from the American Society of Echocardiography, in Collaboration with the American Society of Nuclear Cardiology, the Society for Cardiovascular Magnetic Resonance, and the Society of Cardiovascular Computed Tomography

Hypertrophic cardiomyopathy (HCM) is defined by the presence of left ventricular hypertrophy in the absence of other potentially causative cardiac, systemic, syndromic, or metabolic diseases. Symptoms can be related to a range of pathophysiologic mechanisms including left ventricular outflow tract obstruction with or without significant mitral regurgitation, diastolic dysfunction with heart failure with preserved and heart failure with reduced ejection fraction, autonomic dysfunction, ischemia, and arrhythmias. Appropriate understanding and utilization of multimodality imaging is fundamental to accurate diagnosis as well as longitudinal care of patients with HCM. Resting and stress imaging provide comprehensive and complementary information to help clarify mechanism(s) responsible for symptoms such that appropriate and timely treatment strategies may be implemented. Advanced imaging is relied upon to guide certain treatment options including septal reduction therapy and mitral valve repair. Using both clinical and imaging parameters, enhanced algorithms for sudden cardiac death risk stratification facilitate selection of HCM patients most likely to benefit from implantable cardioverter-defibrillators.

Left ventricular basal muscle bundle in hypertrophic cardiomyopathy: insights into the mechanism of left ventricular outflow tract obstruction

AIMS 

Many factors cause left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM). Previous studies reported that left ventricular basal muscle bundle (BMB) may be associated with LVOTO. We aimed to evaluate the role of BMB in LVOTO by echocardiography.

METHODS AND RESULTS 

Two hundred fifty-six patients diagnosed with HCM were recruited. The morphologic characteristics of left ventricular outflow tract (LVOT) were analysed. BMB was detected in 178 (69.5%) patients by echocardiography. Patients were separated by a resting or provocative LVOT gradient ≥30 mmHg or not. Compared to patients without LVOTO, patients with LVOTO had a significantly thicker basal septum, elongated anterior mitral leaflet (AML), shorter distance between the AML-free margin and the septum or BMB (M-sept/bundle), larger angle between the plane of the mitral valvular orifice and the ascending aorta (MV-AO angle), and higher prevalence of BMB (P < 0.05). According to multivariate analysis, the independent predictors of LVOTO were the presence of BMB, a large basal septum thickness, a short M-sept/bundle, a large MV-AO angle, and a large AML [odds ratio (95% confidence interval): 5.207 (1.381-19.633), 1.386(1.141-1.683), 0.615(0.499-0.756), 1.113(1.054-1.176), and 1.343(1.076-1.677), respectively, P < 0.05]. Of the 256 included patients, 139 underwent surgical myectomy. The transthoracic echocardiography, compared with surgical specimen, showed: sensitivity 98.3%, specificity 82.3%, positive predictive value 97.6%, negative predictive value 87.5%, and accuracy 96.4% to detect BMB.

CONCLUSIONS

BMB is common in HCM. BMB is a risk factor for LVOTO.

Echocardiographic Assessment of the Mitral Valve for Suitability of Repair: An Intraoperative Approach From a Mitral Center

Intraoperative echocardiography of the mitral valve in the precardiopulmonary bypass period is an integral part of the surgical decision-making process for assessment of suitability for repair. Although there are comprehensive reviews in the literature regarding echocardiographic examination of the mitral valve, the authors present a practical stepwise algorithmic workflow to make objective recommendations. Advances in echocardiography allow for quantitative geometric analyses of the mitral valve, along with precise assessment of the valvular apparatus with three-dimensional echocardiography. In the precardiopulmonary bypass period, echocardiographers are required to diagnose and quantify valvular dysfunction, assess suitability for repair, assist in annuloplasty ring sizing, and determine the success or failure of the surgical procedure. In this manuscript the authors outline an algorithmic approach to intraoperative echocardiography examination using two-dimensional and three-dimensional modalities to objectively analyze mitral valve function and assist in surgical decision-making.

Left ventricular outflow tract area after percutaneous transseptal transcatheter mitral valve implantation: A three-dimensional transesophageal echocardiography study

BACKGROUND

Left ventricular (LV) outflow tract (LVOT) obstruction increases mortality in patients undergoing transcatheter mitral valve implantation (TMVI) in degenerated bioprostheses, annuloplasty rings, and native mitral valves. We aimed to evaluate the LVOT area after TMVI using 3-dimensional (3D) transesophageal echocardiography (TEE) and to investigate the preprocedural cardiac geometry that affects the LVOT area after TMVI.

METHODS

We retrospectively reviewed echocardiography data in 43 patients who had TMVI. A change in pressure gradient across LVOT from before to after TMVI (∆PG) and postprocedure 3D LVOT cross-sectional area at the level of the most distal portion of the mitral valve stent that was closest to the LV apex were assessed as evidence of LVOT narrowing.

RESULTS

Transcatheter mitral valve implantation with the use of balloon-expandable valve system was performed for 24 bioprostheses, 7 annuloplasty rings, and 12 native valves. Compared to patients without increase in LVOT gradient (∆PG <10 mm Hg; n = 33), patients with increase in LVOT gradient (∆PG ≥10 mm Hg; n = 10) had smaller LV end-systolic volume (LVESV), greater LV ejection fraction (LVEF), and smaller aorto-mitral (AM) angle. The LVOT area at the valve stent distal edge showed strong association with ∆PG (r = -.68, P < .0001). Only a small AM angle was associated with a small LVOT area at the valve stent distal edge on multivariable analysis, independent of LVESV and LVEF.

CONCLUSION

Small LV size, preserved LVEF, and small AM angle were associated with LVOT narrowing. 3D-derived AM angle might be independently associated with LVOT narrowing in patients undergoing transcatheter mitral valve-in-valve, valve-in-ring, and valve-in-native valve implantation, independent of LVESV and LVEF.

Echocardiographic Evaluation of Successful Mitral Valve Repair or Need for a Second Pump Run in the Operating Room

Detailed preoperative and intraoperative echocardiographic assessment of the mitral valve apparatus is critical for a successful repair. The recent advent of 3-dimensional transesophageal echocardiography has added an extra pivotal role to transesophageal echocardiography in the assessment of mitral apparatus and mitral regurgitation. Because surgeons must rapidly decide whether cardiopulmonary bypass should be continued to be weaned off or a second pump run should be selected, the echocardiographer conducting intraoperative transesophageal echocardiography is required to be trained according to a certain algorithm. This review summarizes the current clinical role of intraoperative transesophageal echocardiography in mitral valve repair in the operating room.

Hemodynamic testing using three-dimensional printing and computational fluid dynamics preoperatively may provide more information in mitral repair than traditional image dataset

Background

Mitral valve repair (MVR) has been considered superior to mitral replacement for degenerative MV disease and even rheumatic diseases. However, the repair rate varies widely depending on the medical center and the surgeons’ experience. The aim of our study was to apply three-dimensional printing (3DP) and computational fluid dynamics (CFD) in surgical simulation to provide reference for surgical decision-making, especially for inexperienced surgeons.

Methods

Our study included retrospective and prospective cohorts. We first enrolled the retrospective cohort of 35 patients who were prepared to have MVR, aiming at exploring the feasibility of surgical simulation using 3DP and CFD. Three-dimensional transesophageal echocardiography (3D-TEE) and computed tomography angiography (CTA) were performed for all patients, and imaging data were fused to construct a 3D digital model. Next, the model was used to make the 3DP dynamic model and for CFD analysis. Mitral repair was simulated in both the 3DP dynamic model and CFD to predict surgical outcomes (grade of regurgitation and vena contracta width) and possible complications (systolic anterior motion, left ventricular outflow tract obstruction). Second, a prospective cohort of 20 patients was studied with 10 patients placed in a 3DP-guided group and 10 in an image-guided group. Rate of transformation to mitral replacement, surgery time, surgical outcomes, and surgical complications were compared between groups.

Results

Of the 35 patients retrospectively enrolled, 14 underwent MVR and 21 were transferred to mitral replacement. Surgical simulation for the 14 MVR patients showed high consistency with in vivo results. The result of surgical simulation for the 21 patients transferred to mitral replacement showed that 7 might have benefited from MVR. In the prospective cohort, the rate of transformation to mitral replacement and surgery time in the 3DP-guided group were significantly lower than those in the image-guided group.

Conclusions

3DP and CFD models based on image data can be used for in vitro surgical simulation. These emerging technologies are now changing traditional models of diagnosis and treatment, and the role of imaging data will no longer be limited to diagnosis but will contribute more to assisting surgeons in choosing treatment strategies.

Techniques for Mitral Valve Re-repair

The emergence of mitral valve repair as the preferred treatment for severe mitral regurgitation (MR) caused by degenerative disease has been accompanied by an increasing number of valve repair failures seen by surgeons. Consequently, the feasibility of valve re-repair vs valve replacement at the time of reoperation has become a valid clinical consideration. In this report we explore the mechanisms of mitral valve repair failure as well as factors that meaningfully influence the likelihood of a successful re-repair. We provide illustrations of techniques for re-repair that we have used with reliable success, informed by the mechanism of repair failure. Lastly, we share our outcomes for mitral valve re-repair over the last 5 years and discuss our experience using the techniques illustrated in this report.

Transcatheter mitral valve in ring, hazards of long anterior mitral leaflet and 3-dimensional rings

OBJECTIVES

The purpose of this study was to define anterior mitral leaflet (AML) length and mitral ring characteristics associated with LVOT obstruction and PVL following MViR.

BACKGROUND

Transcatheter Mitral Valve in Ring (MViR) procedural complications including parvalvular leak (PVL) and left ventricular outflow tract (LVOT) obstruction are frequent.

METHODS

Clinical records, computer tomographic scans (CTs) and echocardiograms of consecutive MViR patients were retrospectively reviewed for anterior mitral leaflet length, CT-simulated neoLVOT, and aortomitral angle among patients with and without MViR-induced LVOT obstruction. Acute and 1-year outcomes are described.

RESULTS

Twenty-two patients underwent MViR. Technical success was achieved in 13/22 (57.1%) patients, limited by paravalvular regurgitation requiring second transcatheter heart valves (THVs) in seven patients. Second valves were needed in 6/11 (54.5%) patients with 3-dimensional rings but 1/11 (9.1%, p = .06) of patients with planar rings. Procedure success at 30 days was achieved in 20/22 (90.9%) patients. There were no procedural, in-hospital, or 30-day deaths. Two patients developed significant LVOT obstruction, one managed with urgent surgery and one with elective alcohol septal ablation. Anterior mitral leaflets were longer among the two patients with LVOT obstruction than the 20 patients who did not develop LVOT obstruction when measured by TEE (30 mm vs. 21 mm, p = .009) or by CT (29 mm vs. 22 mm, p = .026).

CONCLUSIONS

AML >25 mm increases the risk of MViR induced LVOT obstruction. PVL is common, particularly in 3-dimensional rings which can be managed with a second THV.

Alcohol Septal Ablation to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement: First-in-Man Study

OBJECTIVES

This study evaluates outcomes of pre-emptive alcohol septal ablation (ASA) to prevent iatrogenic left ventricular outflow tract (LVOT) obstruction after transcatheter mitral valve replacement (TMVR).

BACKGROUND

LVOT obstruction is a life-threatening complication of TMVR. Bail-out ASA has been described as a therapeutic option for patients with outflow obstruction during TMVR, but little is known about pre-emptive ASA.

METHODS

Multicenter registry of patients with severe mitral valve disease who underwent pre-emptive ASA to mitigate LVOT obstruction risk after TMVR. High risk of LVOT obstruction was predicted in all patients by pre-procedural computed tomographic imaging.

RESULTS

Thirty patients (age 76.1 ± 7.7 years; women 76.7%) with severe mitral valve disease underwent pre-emptive ASA to mitigate TMVR-induced LVOT obstruction risk. Twenty patients underwent mitral valve replacement (14 transseptal, 3 transatrial, 1 transapical, 1 transseptal with percutaneous laceration of anterior mitral leaflet, 1 treated with surgical mitral valve replacement). Eight patients experienced clinical improvement post-ASA. Two patients died before TMVR. Median increase in neo-LVOT surface area post-ASA was 111.2 mm² (interquartile range: 71.4 to 193.1 mm²). Five patients (16.7%) required pacemaker implantation post-ASA. In-hospital and 30-day mortality post-ASA was 6.7% (2/30 patients). After ASA, TMVR was performed successfully in 100% of attempted cases. In-hospital and 30-day mortality post-TMVR was 5.3% (1/19). Mortality of entire cohort was 10% (3/30 patients: 2 post-ASA before TMVR, 1 died 30 days post-TMVR).

CONCLUSIONS

Pre-emptive ASA is associated with a significant increase in predicted neo-LVOT area before TMVR and may enable safe TMVR in patients usually excluded secondary to prohibitive risk of LVOT obstruction.

The Mitral Coaptation to Ventricular Septal Space: Two- and Three-Dimensional Transesophageal Echocardiographic Assessment

OBJECTIVES

To assess the dimensions and changes in the CSEPT (space between the ventricular septum and mitral coaptation point) before and after cardiopulmonary bypass (CPB) and to compare patients with and without aortic valve stenosis (AS) undergoing cardiac surgery.

DESIGN

Retrospective review of intraoperative transesophageal echocardiographic examinations.

SETTING

Single academic medical center.

PARTICIPANTS

The study comprised 91 elective cardiac surgical patients-30 with AS scheduled for aortic valve replacement and 61 without AS (non-AS).

INTERVENTIONS

Two- and 3-dimensional (2D and 3D) analysis of the CSEPT before and after CPB.

MEASUREMENTS AND MAIN RESULTS

Assessment of the CSEPT distances and areas was performed using 2D and 3D imaging before and after CPB. Two-dimensional measures of CSEPT distances were performed using midesophageal 5-chamber and long-axis windows. Three-dimensional measures were performed offline using multiplanar reconstruction. The CSEPT space was smaller after CPB (p < 0.01). Before and after CPB, the midesophageal 5-chamber and long-axis windows were similar to each other, and both were larger than the pre-CPB 3D CSEPT distance. Patients with AS had smaller before and after CPB distances and areas compared with non-AS patients (p < 0.05). The change in CSEPT area in AS patients was 24%.

CONCLUSIONS

The CSEPT space is smaller after CPB and more so for patients with AS undergoing aortic valve replacement. Two-dimensional CEPT distances vary compared with 3D CSEPT distances. Additional study using Doppler analysis will elucidate the added value of 3D assessment of the CSEPT space.

Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making in the Operating Room: A Surgery-Based Approach: From the American Society of Echocardiography in Collaboration with the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons

Intraoperative transesophageal echocardiography is a standard diagnostic and monitoring tool employed in the management of patients undergoing an entire spectrum of cardiac surgical procedures, ranging from "routine" surgical coronary revascularization to complex valve repair, combined procedures, and organ transplantation. Utilizing a protocol as a starting point for imaging in all procedures and all patients enables standardization of image acquisition, reduction in variability in quality of imaging and reporting, and ultimately better patient care. Clear communication of the echocardiographic findings to the surgical team, as well as understanding the impact of new findings on the surgical plan, are paramount. Equally important is the need for complete understanding of the technical steps of the surgical procedures being performed and the complications that may occur, in order to direct the postprocedure evaluation toward aspects directly related to the surgical procedure and to provide pertinent echocardiographic information. The rationale for this document is to outline a systematic approach describing how to apply the existing guidelines to questions on cardiac structure and function specific to the intraoperative environment in open, minimally invasive, or hybrid cardiac surgery procedures.

The Use of a Preoperative Mitral Valve Model to Guide Mitral Valve Repair

BACKGROUND

Mitral valve repair is commonly used to address degenerative or functional changes to the mitral valve apparatus and surrounding ventricular anatomy. Preoperative transoesophageal echocardiogram (TOE) is routinely used to evaluate and identify the precise anatomic location of mitral valve pathology in order to guide repair. However, surgeons currently lack specific guidance regarding the approximate dimensions of the mitral valve they should aim for in order to achieve optimal valve function and avoid adverse outcomes. Therefore, through an observational study, we aimed to develop and test the accuracy of a preliminary mathematical model which represents the geometric relationship between various clinically relevant components of the mitral valve and its surrounding structures.

METHODS

Using established trigonometric principles, the geometric relationship shared between several mitral valve components was represented in a two-dimensional (2D) model and described in a mathematical equation. The output variable of the model is the anteroposterior diameter of the mitral valve. To assess the accuracy of the mathematical model, we compared the model-predicted anteroposterior (AP) diameter against AP diameter measured by postoperative TOE in 42 cases.

RESULTS

The root mean squared error (RMSE) of model predicted AP diameter compared to measured AP diameter was 0.43 cm. The mean absolute percentage error (MAPE) of the model was 17.7%. In 34 out of 42 cases, model-predicted AP diameters were within 25% of AP diameters measured by postoperative TOE.

CONCLUSIONS

Preliminary testing of a simple mathematical model has shown its relative accuracy in representing the geometric relationship between several mitral valve variables. Further research and refinement of the model is required in order to improve its accuracy. We are encouraged that, with further improvement, the model has the potential for clinical application.

Left ventricular outflow tract obstruction following aortic valve replacement: A review of risk factors, mechanism, and management

The presence of dynamic left ventricular outflow tract obstruction (LVOTO) can complicate the postoperative course of patients undergoing surgical aortic valve replacement (AVR). The phenomenon of LVOTO is a consequence of an interplay of various pathoanatomic mechanisms. The prevailing cardiovascular milieu dictates the hemodynamic significance of the resultant LVOTO in addition to the anatomical risk factors. A thorough understanding of the predisposing factors, mechanism, and hemodynamic sequel of the obstruction is pivotal in managing these cases. A comprehensive echocardiographic examination aids in risk prediction, diagnosis, severity characterization, and follow-up of management efficacy in the setting of postoperative LVOTO. The armamentarium of management modalities includes conservative (medical) and surgical options. A stepwise approach should be formulated based on the physiological and anatomical substrates predisposing to LVOTO. The index phenomenon occurs more frequently than appreciated and should be considered when the post-AVR patients exhibit hemodynamic instability unresponsive to conventional supportive measures. The present article provides an overview of various peculiarities of this under-recognized phenomenon in the context of the perioperative management of patients undergoing AVR.

Focused cardiac echocardiography in beach-chair position surgery: A case study

The haemodynamic response to the beach-chair position may be affected by the presence of left ventricular hypertrophy where remodelling of cardiac chambers can potentially lead to left ventricular outflow tract obstruction. We present a case report of severe hypotension in the beach-chair position, where focused cardiac ultrasound identified left ventricular hypertrophy and geometric features that contributed to the hypotensive response. This case illustrates that focused cardiac ultrasound has the potential to alert the clinician preoperatively to left ventricular outflow tract obstruction susceptibility during surgery in the beach-chair position, and intraoperatively to direct management should sudden decreases in blood pressure occur.

Left Ventricular Outflow Tract Obstruction: A Potential Obstacle for Transcatheter Mitral Valve Therapy

Transcatheter mitral valve replacement is the focus of much enthusiasm as the future of therapy for mitral valve disease. Despite technological advances, left ventricular outflow tract (LVOT) obstruction from the valve prosthesis remains an important issue. In this review the authors discuss the pathophysiology of LVOT obstruction in both the surgical and transcatheter experience, imaging evaluation preprocedure, outcomes to date, and therapeutic options.

Mechanical properties of a new thermally deformable mitral valve annuloplasty ring and its effects on the mitral valve

Ideally, an annuloplasty ring's shape should be changed intraoperatively if mitral valve repair is unsuccessful because of a short coaptation length or systolic anterior motion. Several post-implantation adjustable rings have been developed, but they are not freely deformable and are unsuitable for asymmetric repair of the valvular annulus. We developed a novel thermally deformable mitral annuloplasty ring to address these problems and assessed the ring's mechanical properties and its effect on the mitral valve anatomy. This ring was made of polycaprolactone. Tensile and bending tests were performed to evaluate the ring's mechanical properties. The ratio of the transverse and septal-lateral length was determined as 4:3. Using 10 pig hearts, we measured the post-deformation coaptation length and minimum distance from the coaptation to the ventricular septum, which is a factor of abnormal systolic anterior motion of the mitral valve. In the mechanical tests, the ring's yield point was greater than the deformation force of the annulus in humans. In pigs with deformation from "4:3" to "4:2", the coaptation length was significantly increased in each mitral valve part. In pigs with deformation from "4:3" to "4:4", the minimum distance from the coaptation to the ventricular septum was significantly increased. Asymmetrical ring deformation increased the coaptation length only at the deformed area. In conclusion, this new thermally deformable mitral annuloplasty ring could be "order-made" to effectively change the coaptation length in all parts of the mitral valve and the distance from the coaptation to septum post-deformation via intraoperative heating.

Transient systolic anterior motion with junctional rhythm after mitral valve repair in the intensive care unit

Systolic anterior motion (SAM) after mitral valve repair (MVR) can adversely affect hemodynamics due to exacerbation of left ventricular outflow tract obstruction and mitral regurgitation. Intraoperative transient SAM after MVR can usually be managed with hemodynamic maneuvers under continuous monitoring by transesophageal echocardiography (TEE). However, during postoperative intensive care management, transient SAM is seldom diagnosed and the start of treatment may be delayed. We present a case of transient SAM after MVR with abrupt deterioration due to junctional rhythm in the intensive care unit (ICU). TEE revealed that conversion from normal sinus rhythm into junctional rhythm induced the exacerbation of SAM. TEE was useful for identifying the etiology of unstable hemodynamics after cardiac surgery in the ICU, similar to its use in the operating room.