Edge-to-edge repair for prevention and treatment of mitral valve systolic anterior motion

Management of the mitral valve in thoracoscopic trans-mitral myectomy for hypertrophic obstructive cardiomyopathy

Objective

This study aimed to compare clinical outcomes of different mitral valve (MV) management methods in thoracoscopic transmitral myectomy (TTM) and guide surgeons' decision making for hypertrophic obstructive cardiomyopathy (HOCM).

Methods

Seventy-three consecutive patients (41 females; mean age, 53.7 ± 13.6 years) with HOCM who underwent TTM between January 2019 and October 2022 were enrolled and divided into 3 groups according to MV surgical strategy. Clinical outcomes were analyzed and compared among the groups.

Results

None of the patients experienced postoperative residual left ventricular outflow tract obstruction. Percentages of patients with mitral regurgitation (MR) grade ≥3+ (57.5% vs 1.4%) and systolic anterior motion (95.9% vs 2.7%) were significantly decreased postoperatively (P < .001 for both). The preoperative anterior mitral leaflet length was longer in patients in the anterior mitral leaflet direct reattachment group (median, 2.9 cm [interquartile range (IQR), 2.7-3.3 cm] vs 2.7 [IQR, 2.4-2.9 cm]; P = .018), but the postoperative coaptation length was shorter (mean, 8.3 ± 2.1 mm vs 11.1 ± 3.8 mm; P = .038). After a median echocardiography follow-up of 11.8 months, the left ventricular outflow tract gradient (LVOTG) and mitral regurgitation grades remained significantly improved in all 3 groups (P < .05 for all).

Conclusions

Total TTM in selected patients is safe and effective, and all 3 MV management strategies can significantly reduce the LVOTG while improving MR. Mitral valvuloplasty is the preferred initial management strategy over valve replacement except in the scenario of irreparable intrinsic MV disease and valvuloplasty failure.

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.

Transesophageal Echocardiography of Mitral Valve Repair in a Case of Sinus of Valsalva Aneurysm: 2D versus 3D

Mitral valve repair is a common and preferred technique over mitral valve replacement whenever it is feasible. Transesophageal echocardiography (TEE) not only reliably identify repairable mitral valve but also guide appropriate intervention. In addition to two-dimensional (2D) TEE, the three-dimensional (3D) technique clearly delineates size and shape of mitral valve apparatus, and determine the repairability and success of repair technique. We illustrate the 2D and 3D TEE techniques that guided the surgical intervention for Alfieri repair.

Percutaneous mitral valve edge-to-edge repair for late systolic anterior motion after surgical mitral valve repair: a case report

Background

Late post-operative systolic anterior motion (SAM) is a rare but challenging issue. The feasibility of percutaneous mitral valve edge-to-edge repair (PMVR) using the MitraClip to treat late refractory SAM after surgical mitral valve repair has rarely been reported in the literature.

Case summary

An 88-year-old woman with a history of mitral valve repair for a P2 prolapse 14 years before, presented with signs of congestive heart failure. Transoesophageal echocardiogram (TOE) demonstrated significant SAM of the anterior mitral leaflet, resulting in the detachment from the posterior mitral leaflet in mid-to-late systole and severe mitral regurgitation (MR). The heart team decided to perform PMVR using the MitraClip to simultaneously address the issues of SAM and MR, considering the patient's high surgical risk. TOE after the clip deployment at the medial edge of the mitral valve, where the most severe SAM was detected, confirmed resolution of SAM with marked reduction of MR. The patient was discharged home with good haemodynamic compensation.

Discussion

Post-operative SAM typically occurs immediately after the reparative surgery and resolves with conservative treatment; however, persistent SAM requiring repeat surgery remains a serious concern. As an alternative strategy, the MitraClip has some advantages, including low procedural risk, immediately observable results, and the ability to relocate the clip. Meanwhile, the greater risk of post-procedural mitral stenosis, particularly in patients undergoing mitral repair, should be taken into account. In our case, the clip deployment at the medial edge of the valve could minimize the progression of mitral stenosis with a satisfactory reduction of MR.

Resurgence of the edge-to-edge repair of the mitral valve

PURPOSE OF REVIEW

To provide a critical review of the application and outcomes of surgical edge-to-edge (E2E) or Alfieri repair for mitral valvulopathy.

RECENT FINDINGS

The E2E repair is a surgical technique to address mitral regurgitation, particularly suited when the responsible mechanism is bileaflet prolapse combined with enlarged annular area. It can also be used for a range of mitral valve pathologies. Surgically, the technique has been employed as a bailout for unsuccessful repair including residual mitral regurgitation because of systolic anterior motion (SAM). E2E repair should be accompanied by a ring annuloplasty for long-term repair durability. The simplicity of this approach makes it an ideal strategy during minimally-invasive mitral valve repair. It may also be performed via a transaortic approach at the time of aortic valve surgery to address less-than-severe mitral regurgitation or to address residual SAM following myectomy for hypertrophic obstructive cardiomyopathy. We review the surgical indication, potential complications including risk of mitral stenosis and the long-term outcomes of E2E repair.

SUMMARY

The E2E surgical repair is a simple and effective surgical strategy to address a wide range of mitral regurgitation. This is an important technique in the surgical armamentarium especially in cases of minimally-invasive mitral valve surgery.

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.

Minimally Invasive Surgery for Hypertrophic Obstructive Cardiomyopathy With Mitral Regurgitation

BACKGROUND

To summarize the safety and effect of minimally invasive surgery for hypertrophic obstructive cardiomyopathy (HOCM) with significant mitral regurgitation through a single transaortic approach via right minithoracotomy.

METHODS

From 2008 to 2017, 51 HOCM patients with significant mitral regurgitation underwent minimally invasive surgery via right minithoracotomy. Preoperative peak left ventricular outflow tract pressure gradient (LVOTPG) was 96.53 ± 28.72 mm Hg. Preoperative average interventricular septum thickness was 24.31 ± 3.52 mm. All patients had significant mitral regurgitation with systolic anterior motion phenomenon. An oblique incision was made on the anterior wall of ascending aorta or aortic root. Modified Morrow procedure and edge-to-edge mitral valvuloplasty were performed through the single transaortic approach via right minithoracotomy.

RESULTS

All patients successfully underwent the minimally invasive surgery through the single transaortic approach via right minithoracotomy. At discharge, postoperative peak LVOTPG (18.16 ± 6.41 mm Hg) and interventricular septum thickness (14.33 ± 1.99 mm) were significantly decreased compared with preoperative values (P < .05). All patients had no or trivial mitral regurgitation. The average peak mitral valve pressure gradient was 3.39 ± 1.82 mm Hg. Systolic anterior motion phenomenon disappeared in all patients. During follow-up, peak LVOTPG was 19.27 ± 6.10 mm Hg; average interventricular septum thickness was 14.67 ± 1.87 mm. All patients had no or trivial mitral regurgitation. Average peak mitral valve pressure gradient was 3.04 ± 1.52 mm Hg. No systolic anterior motion phenomenon occurred.

CONCLUSIONS

Minimally invasive surgery of modified Morrow procedure and edge-to-edge mitral valvuloplasty through a single transaortic approach via right minithoracotomy could be safely and effectively applied for patients with HOCM and significant mitral regurgitation, which could also effectively eliminate systolic anterior motion phenomenon and without mitral valve stenosis.

Management of systolic anterior motion of the mitral valve: a mechanism-based approach

Although the mechanism of systolic anterior motion (SAM) of the mitral valve is unknown, it is known to have a multifactorial pathophysiology. Echocardiographic analysis of the mitral leaflet revealed the step-wise progression of SAM, and intraventricular flow analysis revealed the contribution of drag force generated by the misled flow below the posterior leaflet. Although several diverse clinical features of SAM are already known, some key features need to be abstracted from among them to understand the regulation of SAM establishment. This paper reviews past articles that have investigated the mechanism of SAM and proposes a mechanism-based concept to provide insights for better comprehension of SAM recognition.

Mitral valve repair over five decades

It has become evident that mitral valve (MV) repair is the preferable treatment for the majority of patients presenting with severe mitral regurgitation (MR). This success clearly testifies that the surgical procedure is accessible, reproducible and is carrying excellent long-lasting results. From the pre-extracorporeal circulation's era to the last percutaneous approaches, a large variety of techniques have been proposed to address the different features of MV diseases. This article aimed at reviewing chronologically the development of these dedicated techniques through their origins and the debates that they generated in the literature.

Intraoperative evaluation of transmitral pressure gradients after edge-to-edge mitral valve repair

Objective

Edge-to-edge repair of the mitral valve (MV) has been described as a viable option used for the surgical management of mitral regurgitation (MR). Based on the significant changes in MV geometry associated with this technique, we hypothesized that edge-to-edge MV repairs are associated with higher intraoperative transmitral pressure gradients (TMPG) compared to conventional methods.

Methods

Patient records and intraoperative transesophageal echocardiography (TEE) examinations of 552 consecutive patients undergoing MV repair at a single institution over a three year period were assessed. After separation from cardiopulmonary bypass (CPB), peak and mean TMPG were recorded for each patient and subsequently analyzed.

Results

84 patients (15%) underwent edge-to-edge MV repair. Peak and mean TMPG were significantly higher compared to gradients in patients undergoing conventional repairs: 10.7±0.5 mmHg vs 7.1±0.2 mmHg; P<0.0001 and 4.3±0.2 mmHg vs 2.8±0.1 mmHg; P<0.0001. Only patients with mean TMPG ≥7 mmHg (n = 9) required prompt reoperation for iatrogenic mitral stenosis (MS). No differences in peak and mean TMPG were observed among edge-to-edge repairs performed in isolation, compared to those performed in combination with annuloplasty: 11.0±0.7 mmHg vs 10.3±0.6 mmHg and 4.4±0.3 mmHg vs 4.3±0.3 mmHg. There were no differences in TMPG between various types of annuloplasty techniques used in combination with the edge-to-edge repairs.

Conclusions

Edge-to-edge MV repairs are associated with higher intraoperative peak and mean TMPG after separation from CPB compared to conventional repair techniques. Unless gradients are severely elevated, these findings are not necessarily suggestive of iatrogenic MS. Thus, in the immediate postoperative period mildly elevated TMPG can be expected and tolerated after edge-to-edge mitral repairs.