Length of second-order chordae as a predictor of systolic anterior motion of the mitral valve

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.

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.