Surgical Management for Systolic Anterior Motion (SAM) of the Mitral Valve in Obstructive Hypertrophic Myopathy

In patients with obstructive hypertrophic cardiomyopathy, left ventricular outflow tract (LVOT) obstruction can be created by the hypertrophic interventricular septum (IVS) as well as systolic anterior motion (SAM) of the anterior mitral leaflet (AML). Sufficient septal myectomy is a fundamental surgical technique to treat LVOT obstruction, however, direct surgical management for SAM is another key aspect. Besides the hypertrophic IVS, mitral valve, subvalvular apparatus, and papillary muscle may play important role for SAM and several surgical techniques have been proposed to treat SAM in literature. In this review, each surgical technique is classified by the anatomical structure on which the surgical procedure is applied. The AML is the main surgical site and is applied with plication (vertical plication, resection–plication–release strategy), extension (the AML extension, transverse incision of the AML), sutured (edge-to-edge repair, anterior leaflet retention plasty), or traction (floating stitch, papillary muscle-to-anterior annulus stitches, paradoxical stitches, transposition of a directed chorda tendinea to the AML). Height reduction of the posterior mitral valve leaflet and papillary muscle reorientation are other techniques. We should understand theoretical aspects of each technique on correction of anatomical and functional abnormalities of the structure and should apply them under proper indication.

Outcomes of loop technique with ring annuloplasty: a > 10-year experience

OBJECTIVE

We assessed the long-term outcomes of the loop technique with ring annuloplasty for mitral regurgitation from our > 10-year experience.

METHODS

We retrospectively reviewed 362 patients who underwent the loop technique with ring annuloplasty via median sternotomy or right mini-thoracotomy for mitral regurgitation. The median follow-up duration was 4.1 years (interquartile range 2.3-5.8 years).

RESULTS

This study involved 147 women and 215 men (median age, 66.5 years). Mitral regurgitation was caused by Barlow's disease in 27 patients. Seven patients required reoperations (recurrent regurgitation caused by technical issues, n = 3; progression of degenerative disease, n = 4). The 5- and 10-year cumulative incidences of reoperation considering death as the competing event were 1.4% and 5.4%, respectively. The 5- and 10-year postoperative cumulative incidences of moderate-to-severe recurrent mitral regurgitation were 4.7% and 13.0%, respectively. Residual regurgitation ≥ mild (hazard ratio, 6.99; 95% confidence interval, 1.520-32.12; P = .012) was an independent risk factor for reoperation. The independent risk factors for moderate-to-severe recurrent regurgitation were residual regurgitation ≥ mild (hazard ratio, 9.60; 95% confidence interval, 3.042-30.31; P < .001) and the loop-in-loop technique (hazard ratio, 3.40; 95% confidence interval, 1.058-10.90; P = .040). The median mean pressure gradient was sustained at almost 3.5 mmHg for > 7 years.

CONCLUSIONS

The loop technique with ring annuloplasty provided excellent results with good hemodynamics beyond the mid-term. Residual regurgitation ≥ mild and the loop-in-loop technique may not be preferable for durable outcomes.

Repair of Mitral Valves with Severe Annular Dilatation and Abundant Leaflet Tissue Using a Prosthetic Ring with a Large Anterior-Posterior Diameter

Backround: Mitral valve (MV) repair in the case of a large anterior-posterior diameter and redundant valve tissue remains challenging and favors repair with a ring that exhibits a large anterior-posterior diameter. Compared to other available rings, the Medtronic Simulus annuloplasty ring shows the largest anterior-posterior diameter. This study reports for the first time mid-term results using this annuloplasty ring. Methods: Between 11/2015 and 12/2019, a total of 378 patients underwent MV repair for degenerative mitral regurgitation using the Medtronic Simulus ring, according to the following selection criteria: large MV annuli, abundant leaflet tissue (i.e., Barlow disease), and risk for SAM. Results: Overall survival after 5 years was 90.8 ± 4.6%. Five patients required valve-related reoperations because of ring dehiscence (n = 1), progression of native valve disease (n = 2), dehiscence of quadrangular resection suture (n = 1), and endocarditis (n = 1). The cumulative incidence of valve-related reoperation at 5 years was 1.3 ± 0.5%. At latest follow-up, echocardiography demonstrated excellent valve function with no/mild MR in 299 patients (94.6%). Two patients (0.6%) had more than moderate MR. No patient developed SAM after repair. Conclusion: Repair of MV with large annuli and abundant leaflet tissue with the Medtronic Simulus annuloplasty ring shows excellent mid-term results regarding reoperation rates and recurrent MR.

Transesophageal Echocardiographic Assessment of the Repaired Mitral Valve: A Proposed Decision Pathway

The indications for mitral valve repair extend across the entire spectrum of degenerative mitral valve disease, ranging from fibroelastic degeneration to Barlow's disease. Collaboration between the surgeon and anesthesiologist is essential for ensuring optimal results. Echocardiographic assessment of the repair can be challenging but is essential to the success of the procedure, as even mild residual mitral regurgitation can portend poor patient outcomes. In addition to determining the severity of residual regurgitation, the anesthesiologist must elucidate the mechanism of disease in order to inform appropriate re-intervention measures. Finally, there are unique complications of mitral valve surgery for the anesthesiologist to understand and assess by echocardiography. This review describes a systematic pathway for a comprehensive intraoperative assessment of the mitral valve following surgical repair.

Mitral Valve Annuloplasty Failure and Percutaneous Treatment Options

PURPOSE OF REVIEW

Mitral valve repair is a common surgical procedure for both primary and secondary mitral regurgitation. With operations performed earlier in disease progression and increased patient longevity, the need for a repeat intervention is not infrequent. With the associated risks of reoperation and patient comorbidities, percutaneous techniques for acute or delayed failure after ring annuloplasty are emerging.

RECENT FINDINGS

Current commercially available devices, used in "off-label" ways, such as the MitraClip, may be effective in repairing recurrent mitral regurgitation after annuloplasty. Similarly, a valve-in-ring transcatheter mitral valve replacement can be considered in patients at high risk for surgical reoperation. These procedures are not without risk, for example, resultant mitral stenosis in the setting of edge-to-edge repair or left ventricular outflow tract (LVOT) obstruction with valve-in-ring transcatheter mitral valve replacement. Newer devices are emerging to permit more options for this subset of patients, which include transcatheter valves that are specifically designed for the mitral position. Undoubtedly, surgical reoperation has increased risk as compared to primary operation. Though percutaneous options are evolving, use in this patient population is currently limited to "off-label" use and is also associated with procedural complexities and risk. It is prudent for cardiologists, surgeons, and anesthesiologists to weigh risks, benefits, and limitations when considering patients for surgical reoperation, percutaneous repair, or transcatheter replacement after failed mitral annuloplasty.

Systolic anterior motion of the mitral valve associated with acute type A aortic dissection: a case report describing one-step surgery of ascending aortic replacement and interventricular septal myectomy

BACKGROUND

Systolic anterior motion of the mitral valve associated with acute type A aortic dissection is rare in daily clinical practice. The prevention of systolic anterior motion is important, because once it occurs, the hemodynamics may become unstable, leading to a critical situation. In the surgical procedure to treat systolic anterior motion, the prevention of new iatrogenic aortic intimal tears is important in the context of acute type A aortic dissection.

CASE PRESENTATION

We present a case of systolic anterior motion in a 68-year-old woman with an acute type A aortic dissection and suspected acute relative adrenal insufficiency. Preoperative transthoracic echocardiography revealed left ventricular outflow tract obstruction due to systolic anterior motion without left ventricular hypertrophy and interventricular septal bulging due to a narrow aorto-mitral angle. We successfully performed a one-step surgery for ascending aortic replacement and interventricular septal myectomy using the needle stick technique for the treatment of systolic anterior motion.

CONCLUSIONS

Concomitant interventricular septal myectomy using the needle stick technique with thoracic aortic replacement is a safe and feasible technique. Interventricular septal myectomy may be effective in preventing postoperative unstable hemodynamics due to systolic anterior motion in the management of acute aortic dissection.

A Narrative Review of the 2020 Guidelines for Use of Transesophageal Echocardiography to Assist with Surgical Decision- Making by the Cardiac Anesthesiologist in the Operating Room

Transesophageal echocardiography (TEE) has become an integral part in helping to diagnose, manage, and assess interventions in the cardiac operating room. Multiple guidelines have been created by the American Society of Echocardiography for performing a TEE examination for different cardiac pathologies. The operating room can provide unique challenges when performing a TEE examination, which include hemodynamic instability, time constraints, and use of general anesthesia. The Guideline for the use of TEE to assist in surgical decision- making in the operating room recently was published to provide a starting protocol for conducting a TEE examination for different cardiac surgeries and for using the information obtained to interpret and to communicate findings to the surgical team. This present narrative review focuses and expands upon the relevant portions for the cardiac anesthesiologist.

Sutures on the Anterior Mitral Leaflet to Prevent Systolic Anterior Motion

Mitral valve systolic anterior motion and associated regurgitation remain a challenging problem in mitral valve plasty. A simple procedure to correct intraoperative systolic anterior motion using sutures applied between the tip of the anterior leaflet and the posterior annulus is presented. This technique reduces the movement of the anterior leaflet toward the septum while maintaining sufficient valve orifice area.

Acute Severe Functional Mitral Regurgitation After Non-Mitral Valve Cardiac Surgery-Left Ventricular Dyssynchrony as a Potential Mechanism

Functional mitral regurgitation (MR) describes valve leakage in the absence of disease or damage to the mitral leaflets or subvalvular apparatus. Significant, new functional MR after cardiopulmonary bypass (CPB) may result from a number of intraoperative processes, including left ventricular (LV) ischemia and enlargement, left atrial enlargement secondary to increased filling pressure, and systolic anterior motion of the mitral valve after mitral repair. Assessment of new MR after CPB is important because it may direct hemodynamic maneuvers or prompt reinitiation of CPB if surgical intervention is deemed necessary. Described extensively in the electrophysiology literature but underreported as a cause of MR after CPB, LV dyssynchrony represents another possible mechanism of functional MR, in which resynchronization of conduction via pacing maneuvers may prove beneficial. Herein, a series of 4 patients in whom new MR was found after non-mitral valve cardiac surgery in the setting of normal LV systolic function is presented, and LV dyssynchrony is proposed as a major contributing factor. The findings suggested that the concomitant observation of new or worsened functional MR, together with normal global and regional LV systolic function, should lead the clinician to consider ventricular dyssynchrony as a possible cause. Attempts to improve or alter ventricular conduction should be considered before contemplating a return to CPB for mitral valve intervention.

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.

A Floating Stitch on the Anterior Mitral Leaflet Can Eliminate Systolic Anterior Motion in Hypertrophic Obstructive Cardiomyopathy

Reducing the systolic anterior motion is a key way of resolving left ventricular outflow tract obstruction in surgery for hypertrophic obstructive cardiomyopathy. We developed a new technique using a floating stitch on the anterior mitral leaflet (AML). It is applied just to the middle of the tip of the AML and fixed to the annuloplasty ring at the middle of the posterior annulus. The AML is prevented from touching the interventricular septum and systolic anterior motion can theoretically be solved.

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.

Assessment of Mitral Valve Repair With Exercise Echocardiography: Artificial Chordae vs Leaflet Resection

Mitral valve (MV) repair with artificial chordae (AC) or leaflet resection (LR) is associated with good hemodynamics at rest. The aim of this study was to compare these techniques in terms of exercise capacity and echocardiographic parameters of hemodynamics at rest and peak exercise. We conducted a study in 2015 of 56 patients, who had undergone surgery for degenerative posterior mitral leaflet prolapse between 2005 and 2014 using either AC (n = 24) or LR (n = 32). Clinical data were collected, exercise capacity was measured, and resting echocardiography and peak exercise echocardiography were performed. No significant differences were detected among groups regarding exercise duration or peak exercise workload measured in Watts (W) (AC: 136 ± 43 W and LR: 131 ± 40 W; P = 0.65). The mean mitral gradient at rest was 3.0 ± 1.3 mm Hg in the AC group and 3.0 ± 1.0 mm Hg in the LR group (P = 0.90). The mean MV gradients at peak exercise did not differ significantly between groups (AC: 8.3 ± 3.4 and LR: 11.3 ± 8.7; P = 0.19). Four patients (17%) in the AC group and 1 (3%) in the LR group had systolic anterior motion, P = 0.15. We conclude that both methods of posterior MV leaflet repair were associated with good hemodynamics at rest and peak exercise. The groups had comparable exercise capacity. MV pressure gradients at rest and peak exercise were similar in both groups.

Mastering Mitral Leaflets Coaptation After Valve Repair with Adjustable Mitral Annuloplasty Ring: Proof of Concept in Mock Loop Study

This investigation sought to determine the feasibility of a novel mitral ring designed to reshape mitral annulus on beating heart, after surgery. The mitral ring is intended to improve mitral leaflets coaptation to correct residual and recurrent mitral regurgitations. It could also provide progressive correction of mitral regurgitation. The device was tested in ex vivo beating heart model. The novel mitral ring is selectively deformable in P1, P2, and P3 segments using a dedicated angioplasty-type balloon. The deformation should increase leaflets coaptation, reducing distance between the two leaflets. It was implanted using standard surgical techniques. The mock loop is based on passive beating heart. Mitral valve (MV) functioning was evaluated in terms of leaflets coaptation height at P2 level using epicardial echocardiography. The test has been completed on eight swine hearts. Ring size was 30 mm. The balloons were inserted in the connecting line. Each segment of the posterior annulus was independently activated over three progressive positions. Balloon inflation pressures were between 15 and 21 bar. Maximum coaptation height increase was 7 mm. Mean pressure gradient across the MV was 1.7 ± 0.3 mm Hg after complete activation of the device. The device allowed significant increase in coaptation height at P2 level after adjustments at P1, P2, and P3. Results were consistent and reproducible. This feasibility study demonstrates the possibility to reshape the mitral annulus on beating heart to precisely increase MV leaflets coaptation height.

Medical Management (β Blocker ± Disopyramide) of Left Ventricular Outflow Gradient Secondary to Systolic Anterior Motion of the Mitral Valve After Repair

Systolic anterior motion of the mitral valve (SAM) occurs intraoperatively after mitral valve repair (MVRr) in up to 14% of cases and typically resolves in the operating room with conservative measures. Less commonly SAM may also occur in the early or late postoperative period. The clinical course and optimal management of such cases is poorly defined, but reoperation is common. We describe our experience using disopyramide to successfully treat postoperative SAM refractory to beta blockade. Seven patients were retrospectively identified with mitral valve prolapse who underwent MVRr from 2003 to 2015 and were found during follow-up to have severe SAM with a left ventricular outflow tract (LVOT) gradient not observed intraoperatively. All 7 patients were successfully managed medically. In 5 cases, SAM persisted even after maximization of beta blockade, and the addition of disopyramide led to significant improvement or resolution of SAM, the LVOT gradient, and mitral regurgitation. The postoperative LVOT gradient initially exceeded 30 mm Hg in 6 of 7 patients. In 2 patients, the LVOT gradient exceeded 100 mm Hg, and both were managed medically with disopyramide with complete resolution of SAM. In conclusion, SAM after MVRr typically follows a benign clinical course and can be managed medically in most cases. When an initial treatment strategy of beta blockade is insufficient, the addition of disopyramide can effectively alleviate and terminate this condition and should be considered before reoperation.