New Repair Technique of Systolic Anterior Motion (SAM) of Mitral Valve in Patient with Hypertrophic Obstructive Cardiomyopathy (HOCM): A Case Report

Introductions: The predominant cause of left ventricular outflow tract (LVOT) obstruction in patients (pts) with hypertrophic obstructive cardiomyopathy (HOCM) is a systolic anterior motion (SAM) of the mitral valve (MV), which interacts with hypertrophic septum. SAM of the MV can additionally cause a gap in coaptation of anterior (AML) and posterior (PML) MV leaflets, and mitral regurgitation (MR) of varying degrees could occur. In pts with HOCM and severe MR, surgical myectomy is the gold standard of treatment and resolves MR and LVOT obstruction in 90%. However, LVOT obstruction and MR may persist even after extensive myectomy. In this case report we describe a modified Alfieri technique by additional fixation of the edge of AML to the annulus of corresponding portion of PML (edge-to-annulus repair) in patient with HOCM and severe MR due to SAM.

Case report: A 58-year-old man suffered from HOCM for more than 25 years. Recently, he complained about dyspnea and dizziness. Echocardiographic examination confirmed severe LVOT obstruction with a mean resting LVOT gradient of 60 mm Hg, a maximum LVOT gradient of 110 mm Hg under exertion, and additional severe MR due to SAM. Thus, the patient was scheduled for elective cardiac surgery.

After extended myectomy the intraoperative transesophageal echocardiographic (TEE) evaluation showed a residual increased LVOT gradient and further MR due to SAM. The cardiopulmonary bypass (CPB) was resumed and the exposure of MV revealed dilated annulus and elongated AML. A double-armed 4 × 0 Prolene U-stich suture was inserted to the edge of A2-segment of the AML. This suture was then tied to the corresponding portion of the posterior mitral annulus in the P2 region, to address the long AML high predisposing to SAM. Thereafter, MV annuloplasty was performed with a 38 mm Physio II ring (Edward Life Science, Irvine, California, United States). The weaning from CPB after 116 minutes of cross-clamp time was uneventful. The reexamination in TEE revealed competent MV and normal LVOT gradient (peak gradient 14 mm Hg). The postoperative course was uneventful and the patient was discharged home on postoperative day 8. Six months after surgery, he presented in excellent clinical condition with negligible LVOT gradient (7 mm Hg), no SAM, and mild regurgitation of MV with no stenosis.

Conclusions: Myectomy with additional edge-to-annulus repair and annuloplasty of MV might eliminate MR and increased LVOT gradient in pts with HOCM due to SAM.